US 20050245866 A1
The present invention provides a method for exchanging catheters while containing emboli within a blood vessel such as a saphenous vein graft, coronary artery, carotid artery, or other similar vessels. A guidewire is inserted through the vasculature of a patient until it reaches a desired treatment site. A therapy catheter is then inserted over the guidewire until the distal end of the therapy catheter reaches the treatment site. The guidewire has a distally mounted balloon which is inflated to occlude the blood vessel. Then, the therapy catheter provides means for treating the vessel at the treatment site. After treatment, the therapy catheter is removed from the guidewire and exchanged with an aspiration catheter which rides over the guidewire until the distal end of the aspiration catheter reaches the treatment site. The aspiration catheter applies negative pressure to remove any emboli formed by the treatment procedure.
29. A catheter system for emboli containment, comprising:
a guidewire having a proximal end and a distal end;
an occlusive device connected to the distal end of the guidewire, the occlusive device being actuatable between an expanded state in which the occlusive device engages at least a portion of the walls of a blood vessel, and a nonexpanded state in which the occlusive device does not engage the walls of the blood vessel;
a first treatment catheter having a proximal end and a distal end and a lumen extending therethrough; and
a second treatment catheter having a proximal end and a distal end and a lumen extending therethrough;
wherein the first treatment catheter is adapted to be delivered over and then removed from the guidewire, and the second treatment catheter is adapted to be delivered over and then removed from the guidewire following removal of the first treatment catheter, and wherein the occlusive device is capable of maintaining its expanded state while the first treatment catheter is removed from the guidewire and while the second treatment catheter is delivered over the guidewire.
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39. A catheter system for emboli containment, comprising:
a guidewire having a proximal end and a distal end;
an occlusive device connected to the distal end of the guidewire, the occlusive device being actuatable between an expanded state in which the occlusive device engages at least a portion of the walls of a blood vessel, and a nonexpanded state in which the occlusive device does not engage the walls of the blood vessel; and
a catheter having a proximal end and a distal end and a lumen extending therethrough, the catheter being adapted to be delivered over and removed from the guidewire;
wherein the occlusive device is capable of maintaining its expanded state while the catheter is either advanced over or removed from the guidewire.
40. The catheter system of
41. The catheter system of
42. The catheter system of
43. The catheter system of
44. The catheter system of
45. The catheter system of
46. The catheter system of
This application is a continuation-in-part of application Ser. No. ______, entitled LOW PROFILE CATHETER VALVE AND INFLATION ADAPTOR, filed Nov. 20, 1997 (Attorney Docket No. PERCUS.006CP1), the entirety of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to medical catheters used in treating saphenous vein grafts, coronary arteries, and other blood vessels, and more particularly, to a method for exchanging catheters during emboli containment in such vessels.
2. Description of the Related Art
Guidewires are conventionally used to guide the insertion of various medical instruments, such as catheters, to a desired treatment location within a patient's vasculature. In a typical procedure, the clinician forms an access point for the guidewire by creating an opening in a peripheral blood vessel, such as the femoral artery. The highly flexible guidewire is then introduced through the opening into the peripheral blood vessel, and is then advanced by the clinician through the patient's blood vessels until the guidewire extends across the vessel segment to be treated. Various treatment catheters, such as a balloon dilatation catheter for a percutaneous transluminal coronary angioplasty, may then be inserted over the guidewire and similarly advanced through vasculature until they reach the treatment site.
In certain treatment procedures, it is desirable to successively introduce and then remove a number of different treatment catheters over a guidewire that has been placed in a particular location. In other words, one treatment catheter is “exchanged” for another over a single guidewire. Such an exchange typically involves withdrawing the treatment catheter over the guidewire until the treatment catheter is fully removed from the patient and the portion of the guidewire which extends from the patient. The guidewire is then available to act as a guide for a different treatment catheter.
As can be readily appreciated, the withdrawal of treatment catheters over a placed guidewire may result in the guidewire being displaced from its position. To overcome this difficulty, the prior art has developed “anchorable” guidewires, which generally feature some structure on their distal ends to releasably secure the guidewire at a particular location in the patient for the duration of the medical procedure. One such anchorable guidewire is disclosed in U.S. Pat. No. 5,167,239 to Cohen et al., which discloses a hollow guidewire with an inflation, lumen and an expandable balloon on its end. The Cohen device includes a removable inflation manifold, and a check valve to maintain the balloon in the inflated state when the manifold is removed. The check valve apparatus used by the Cohen device is relatively bulky, and is described as having an outer diameter in its preferred embodiment of 0.0355 inches. Consequently, any treatment catheter intended to be inserted over the Cohen device must have an interior guidewire lumen larger than the outer diameter of the Cohen valve, which for the preferred embodiment, requires an interior lumen with a diameter of more than 0.0355 inches. Cohen also does not address the problem of emboli containment.
As is readily appreciated by those of skill in the art, increasing the interior lumen size of a treatment catheter results in an increase in the outer diameter of the treatment catheter. However, many blood vessels where it is desirable to apply catheter treatment are quite narrow. For example, the left coronary arteries are blood vessels having diameters ranging from 2 to 4 mm, and are susceptible to plaque. Similarly, saphenous vein grafts (SVG) and the carotid arteries are also quite small and susceptible to plaque, and could not practically be treated by larger diameter devices.
Human blood vessels often become occluded or completely blocked by plaque, thrombi, other deposits, emboli or other substances, which reduce the blood carrying capacity of the vessel. Should the blockage occur at a critical place in the circulatory system, serious and permanent injury, or even death, can occur. To prevent this, some form of medical intervention is usually performed when significant occlusion is detected.
Coronary heart disease is an extremely common disorder in developed countries, and is the leading cause of death in the U.S. Damage to or malfunction of the heart is caused by narrowing or blockage of the coronary arteries (atherosclerosis) that supply blood to the heart. The coronary arteries are first narrowed and may eventually be completely blocked by plaque, and may further be complicated by the formation of thrombi (blood clots) on the roughened surfaces of the plaques. Myocardial infarction can result from atherosclerosis, especially from an occlusive or near occlusive thrombi overlying or adjacent to the atherosclerotic plaque, leading to death of portions of the heart muscle. Thrombi and emboli also often result from myocardial infarction, and these clots can block the coronary arteries, or can migrate further downstream, causing additional complications.
Various types of intervention techniques have been developed which facilitate the reduction or removal of the blockage in the blood vessel, allowing increased blood flow through the vessel. One technique for treating stenosis or occlusion of a blood vessel is balloon angioplasty. A balloon catheter is inserted into the narrowed or blocked area, and the balloon is inflated to expand the constricted area. In many cases, near normal blood flow is restored. It can be difficult, however, to treat plaque deposits and thrombi in the coronary arteries, because the coronary arteries are small, which makes accessing them with commonly used catheters difficult.
Other types of intervention include atherectomy, deployment of stents, introduction of specific medication by infusion, and bypass surgery. Each of these methods are not without the risk of embolism caused by the dislodgement of the blocking material which then moves downstream. In addition, the size of the blocked vessel may limit percutaneous access to the vessel.
In coronary bypass surgery, a more costly and invasive form of intervention, a section of a vein, usually the saphenous vein taken from the leg, is used to form a connection between the aorta and the coronary artery distal to the obstruction. Over time, however, the saphenous vein graft may itself become diseased, stenosed, or occluded, similar to the bypassed vessel. Atherosclerotic plaque in saphenous vein grafts tends to be more friable and less fibrocalcific than its counterpart in native coronary arteries.
Diffusely diseased old saphenous vein grafts with friable atherosclerotic lesions and thrombi have therefore been associated with iatrogenic distal embolic debris. Balloon dilatation of saphenous vein grafts is more likely to produce symptomatic embolization than dilatation of the coronary arteries, not only because of the difference in the plaque but also because vein grafts and their atheromatous plaques are generally larger than the coronary arteries to which they are anastomosed. Once the plaque and thrombi are dislodged from the vein, they can move downstream, completely blocking another portion of the coronary artery and causing myocardial infarction. In fact, coronary embolization as a complication of balloon angioplasty of saphenous vein grafts is higher than that in balloon angioplasty of native coronary arteries. Therefore, balloon angioplasty of vein grafts is performed with the realization that involvement by friable atherosclerosis is likely and that atheroembolization represents a significant risk.
Because of these complications and high recurrence rates, old diffusely diseased saphenous vein grafts have been considered contraindications for angioplasty and atherectomy, severely limiting the options for minimally invasive treatment. However, some diffusely diseased or occluded saphenous vein grafts may be associated with acute ischemic syndromes, necessitating some form of intervention.
Furthermore, attempts heretofore have been made to treat occlusions in the carotid arteries leading to the brain. However, such arteries have been very difficult to treat because of the possibility of dislodging plaque which can enter various arterial vessels of the brain and cause permanent brain damage. Attempts to treat such occlusions with balloon angioplasty have been very limited because of such dangers. In surgical treatments, such as endarterectomy, the carotid artery is slit and plaque is removed from the vessel in the slit area. Such surgical procedures have substantial risk associated with them which can lead to morbidity and mortality.
In other procedures, such as in angioplasty and in the treatment of peripheral arteries and veins, there is the possibility that the guide wires and catheters used in such procedures during deployment of the same may cause dislodgement of debris or emboli which can flow downstream and cause serious damage, such as stroke, if they occlude blood flow in smaller vessels. Moreover, when treating aneurysms, coils or other objects deployed to fill the aneurysm may break free and become lost downstream. Thus, in summary, embolization and migration of micro-emboli downstream to an end organ is a major concern of cardiologists during catheterizations.
Accordingly, what is needed is an exchange method for use during treatment of narrow blood vessels such as the carotid arteries, coronary arteries and saphenous vein grafts. Specifically, what is needed is a method which allows an exchange of catheters while a distal occluding device is deployed to perform treatment within the vessel and to contain emboli produced, created, or used during the treatment procedure. Furthermore, because a distal occluding device may block the flow of blood to vital organs, it is desirable that the exchange be performed quickly and easily in order to minimize the time that the blood vessel is occluded.
The present invention satisfies the above needs by providing a method for exchanging catheters during an emboli containment procedure. As described herein, the term “emboli” may refer to any debris, particles, or other objects found, created or placed in a blood vessel. “Emboli containment” may refer to emboli removal, neutralization, disintegration, minimization, or simply to preventing emboli from moving downstream. In essence, “containment” refers to any procedure which reduces the deleterious effects that emboli may have on the patient. The preferred exchange method is particularly useful in angioplasty and similar procedures in smaller blood vessels such as the coronary or carotid arteries or in saphenous vein grafts. The exchange method described herein can be accomplished rapidly to minimize the time that a treated blood vessel is occluded for treatment.
For example, in most angioplasty procedures, a guidewire is first introduced into the vasculature of a patient until the distal end of the guidewire is near the occlusion or stenosis. The guidewire preferably bears a distal occlusion device, such as a balloon, filter, coil, or combination of these elements. The occlusive device is preferably activated prior to performing therapy to remove or reduce an occlusion or stenosis, to provide a working area and to prevent particles and debris produced during therapy from migrating downstream. The occlusive device may completely or partially occlude the vessel.
In order to perform an exchange over the guidewire catheter, the catheter must be made such that the occlusive device remains activated in order to minimize particles from going downstream. Furthermore, the proximal end of the guidewire must have a low profile to accommodate other catheters which are to be advanced over the guidewire. In one preferred method, a therapy catheter is advanced over a proximal end of the guidewire to the site of the plaque or lesion. After deploying the occlusive device on the end of the guidewire, therapy is performed on the lesion by the therapy device. One preferred therapy device is a dilatation catheter which compresses the lesion against the walls of the vasculature. In addition to dilatation balloon catheters, other forms of therapy may be used to dislodge, disintegrate, or neutralize the plaque. One method is to provide an ultrasonic catheter which targets the plaque and destroys it using shock waves. Another method is to use a vibration delivery catheter, which causes the plaque to break up due to a vibrating wire. Another method uses a drug delivery catheter provided over the guidewire, which provides fluids to dissolve the plaque. Other types of therapy include radiation therapy.
After treatment of the plaque by an appropriate therapy method, emboli often remain in the working area. The therapy catheter can then be removed and exchanged with an emboli removal catheter, such as an aspiration catheter for aspirating the emboli from the working area. The aspiration catheter can then be exchanged with another therapy catheter, such as a catheter bearing a stent which is deployed onto the lesion for maintaining the opening of the blood vessel.
The present invention in a preferred embodiment allows for the rapid and easy exchange of catheters by deploying the occlusive device in stages. For instance, when a guidewire with a distal occlusion balloon is used, the balloon is inflated only when there is danger of emboli moving downstream. Thus, if treatment of the stenosis consists of a dilatation procedure and deployment of a stent, the occlusion balloon will be inflated for a first inflation period during which the dilatation balloon works on the plaque, the dilatation catheter is exchanged with an aspiration catheter, and the aspiration catheter removes emboli from the vessel. After aspiration, the occlusion balloon can safely be deflated to allow blood flow for a period to organs downstream. An exchange can then be performed with another therapy catheter, such as a stent deploying catheter, and the occlusion balloon is reinflated for a second inflation period to deploy a stent to the location of the stenosis. By employing an exchange method with vessel occlusion occurring in stages, the time that blood flow is occluded in the vessel decreases, thereby minimizing the risks to the patient and presenting significant advantages over known technology. The speed of exchange is also improved by using an adaptor which allows for easy and quick handling of the guidewire for inflation and deflation.
I. Exchange Method During Emboli Containment
The method discussed herein allows for the rapid exchange of catheters during angioplasty and similar procedures. In particular, the preferred method of the present invention is adapted for use in the treatment and removal of an occlusion in a blood vessel in which the occlusion has a length and a width or thickness which at least partially occludes the vessel's lumen. Thus, the catheters of a preferred aspect of the present invention are effective in treating both partial and complete occlusions of the blood vessels. As used herein, “occlusion” includes both partial and complete occlusions, stenoses, emboli, thrombi, plaque and any other substance which at least partially occludes the vessel's lumen.
The method and apparatus of the present invention preferably can be used in any vessel of the body where the pressure is at least 0.2 psi at any stage of the heart pumping cycle, and more preferably, is about 1.2 psi, with a flow rate of at least 10 cc per minute. The method and apparatus are particularly suited for use in removal of occlusions from saphenous vein grafts, coronary and carotid arteries, and in other non-branching vessels having similar pressures and flow where a suitable working area can be created. Although the present invention will be described in connection with a saphenous vein graft, it should be understood that this application is merely exemplary, and the method can be used in other blood vessels as well. For example, it will be appreciated that the described method can also be applied to coronary arteries, carotid arteries, or any other arteries or veins where treatment and containment of emboli is desired.
A. The Preferred Treatment Method
In one preferred aspect of the present invention, a catheter or guidewire 10 is inserted into the human body 1 through a groin insertion site 3, as shown in
The catheter 10 used for the preferred method is shown in
1. Insertion of the Guidewire
The guidewire 10 should be sized so as to be slidable with respect to the therapy, aspiration or other catheters to be inserted over the guidewire. When the guidewire is properly positioned inside the vessel, the occlusive device at the distal end of the guidewire is actuated to occlude the vessel distal to the existing lesion to create a working area. With the occlusive device effectively blocking the flow of emboli downstream, various catheters may be exchanged over the guidewire 10 to treat the vessel without the risk of emboli flowing downstream and cutting off blood flow to vital organs.
In non-bifurcated areas of the blood vessels, it has been discovered that fluid from the proximal portion of the same vessel acts as an infusion source. One therefore need only occlude the distal portion of the vessel to create a working area surrounding the occlusion and allow blood to flow from the proximal portion of the vessel into the working area. It should be noted that, as used herein, “proximal” refers to the portion of the apparatus closest to the end which remains outside the patient's body, and “distal” refers to the portion closest to the end inserted into the patient's body. Thus, the embodiment described above only provides an occlusive device distal to the working area.
However, an embodiment is also contemplated wherein the working area is defined by occlusive devices located both proximal and distal to the lesion 42. In this embodiment, a guide catheter having a single lumen is first introduced into the patient's vasculature through an incision made in the femoral artery or vein in the groin and used to guide the insertion of other catheters and devices to the desired site. This guide catheter carries an occlusion balloon or other occlusive device to occlude the vessel proximal to the lesion 42. Following insertion of the guide catheter, a second catheter is inserted through the guide catheter and past the site of the occlusion. This second catheter serves as the exchange catheter or guidewire over which various catheters may be advanced and removed.
2. Therapy Catheter/Aspiration Catheter Exchange
As shown in
The therapy catheter 50 of the preferred embodiment includes a dilatation balloon 52 located on the distal end of an elongate tubular body 54. The tubular body 54 has a lumen 56 extending from a proximal end to the distal end of the tubular body which is sized to override the guidewire 10 until the dilatation balloon 52 reaches the point of the lesion 42. Once balloon 52 is in place, the occlusion balloon 20 on guidewire 10 is inflated to at least partially block blood flow. Then, the dilatation balloon 52 is inflated to compress the plaque 42 against the walls of the blood vessel. This inflation has the effect of dislodging some plaque and creating emboli 48 (shown, in
In the preferred method, after treatment by the therapy catheter 50 is completed, the therapy catheter is completely removed from the body by sliding the therapy catheter over the guidewire 10 in a proximal direction away from the lesion and out of the body, leaving only the guidewire 10 as shown in
Preferably, the procedure described above is perform twice using a predilatation catheter and a dilatation catheter. The predilatation catheter is a first therapy catheter which is advanced over the proximal end of the guidewire 10 to the point of the lesion 42. The balloon on the distal end of the predilatation catheter has a first inflation diameter designed to perform a first treatment to the lesion 42. The predilatation catheter is then exchanged with an aspiration catheter to aspirate emboli formed by the first treatment, while the occlusion balloon remains inflated. After aspiration, the occlusion balloon 20 is deflated to allow blood to flow to organs downstream, and then reinflated after exchange of the aspiration catheter for the dilatation catheter. This second therapy catheter has a dilatation balloon with a larger inflation diameter than the first dilatation balloon so as to further compress the plaque 42 against the vessel walls. Once this treatment is completed, the second therapy catheter is exchanged with the aspiration catheter for removing emboli from the blood system.
Further exchanges of therapy catheters having successively larger dilatation balloons with aspiration catheters are also contemplated by the present invention, with each exchange occurring while the distal occlusion balloon is inflated. Moreover, it is not always necessary to follow treatment with a therapy catheter with an exchange for an aspiration catheter. Therapy catheters can be exchanged with other therapy catheters to perform further treatment in the blood vessel before an exchange with an aspiration catheter is made.
3. Stent Catheter Exchange
In the preferred method of the present invention, following treatment of the lesion and aspiration by one or more sequences as described above, the occlusion balloon 20 is deflated to resume blood flow to the vessel. Another catheter exchange is performed whereby the aspiration catheter is removed from the guidewire 10 and exchanged with a deployment catheter carrying a stent. As shown in
B. Alternative Exchange Methods
The method described above is merely exemplary, and it should be recognized that the catheter exchange method may utilize a variety of exchanges of different types of catheters while emboli are being contained. The term “therapy catheter” is meant to include any of a number of known devices used to treat an occluded vessel. For example, a catheter carrying an inflatable balloon for use in balloon angioplasty can be delivered to dilate the occlusion. Thermal balloon angioplasty includes the use of heat to “mold” the vessel to the size and shape of the angioplasty balloon. Similarly, an intravascular stent can be delivered via a balloon catheter and deployed at the site of the occlusion to keep the vessel open. Cutting, shaving, scraping or pulverizing devices can be delivered to excise the occlusion in a procedure known as atherectomy. A laser or ultrasound device can also be delivered and used to ablate plaque in the vessel. Various thrombolytic or other types of drugs can be delivered locally in high concentrations to the site of the occlusion. It is also possible to deliver various chemical substances or enzymes via a catheter to the site of the stenosis to dissolve the obstruction. The term “therapy catheter” encompasses these and similar devices.
After treatment of the plaque by the shock wave generator, an aspiration catheter 60 as described in
The exchange method as described in a preferred aspect of the present invention is not applicable solely to procedures dislodging emboli. Rather, the present exchange method also applies to any situation wherein a distally occluding device prevents the migration of undesired particles downstream. For instance, as shown in
C. Exchange Methods Over Alternative Occlusive Devices
Although the embodiments described above refer to a distally occluding balloon to prevent emboli from migrating downstream, other methods for occluding the blood vessel may be used while performing the exchange method described in a preferred aspect of the present invention. With respect to all of these methods, the, proximal ends of the expansion members are sized to allow an exchange of catheters over the catheter or guidewire bearing the expansion member. These methods as briefly discussed herein are described in further detail below in the section entitled “Expansion Members.”
The preferred exchange method of the present invention may also be performed over catheters or guidewires employing non-self-expanding or mechanically deployed sealing mechanisms. As shown in
D. Speed of Exchange
The method described by a preferred aspect of the present invention is particularly advantageous in that it allows for a rapid exchange of catheters to reduce the time that a blood vessel is occluded by a balloon or other occlusive device.
Second and third inflation durations as indicated in
Thus, the inflation durations as shown in
The preferred method also reduces the treatment time by providing the catheter 10 with a side-access inflation port 22, as shown in
Furthermore, use of an adaptor makes the catheter much easier to handle. Because the guidewire 10 is so small, it may difficult to handle by clinicians. By using an adaptor, however, the clinician need only insert the wire into the adaptor, close the adaptor, and actuate the adaptor, as described in further detail below.
Additionally, as shown in
Moreover, by providing an access port on the side of the tubular body 18, the port 22 can be made with a large cross-section to increase the amount of fluid passing through the port. This in turn decreases the time necessary for inflating or deflating balloon 20. In addition, as described in more detail below, the use of a side-access port allows for more efficient opening and closing of the port 22. Preferably, a sealing member 30 moves slidably within tubular body 18 to plug and unplug port 22. Because member 30 remains attached to the catheter 10 even when the port 22 is open, the operator never has to remove the sealing member. Accordingly, the sealing member is always in place, thereby reducing the time that it takes to open or close inflation port 22.
The speed of exchange is also increased by using an aspiration catheter with a high volume syringe. As shown in
E. Diagnostic Methods
The preferred exchange method of the present invention is also applicable to diagnostic methods. In one preferred aspect of the present invention, a method is provided wherein emboli found or created in the body are removed from the body for diagnostic testing. A guidewire with a distal occlusive device is inserted into the body to a point distal of plaque. A therapy catheter is advanced over the guidewire to the location of the plaque. After the distal occlusion device is deployed, a therapy treatment, such as inflation of a dilatation balloon or any other means as described above, is performed to break up the plaque and produce emboli. The therapy catheter is then exchanged with an aspiration catheter while the occlusion device remains deployed, and the aspiration catheter removes the particulate matter for analysis.
In the procedures conducted on the 24 patients described above in
Vein graft aspirate was collected in tubes containing EDTA-citrate buffer and treated with 1% saporin to lyse interfering red blood cells. The remaining material was fixed in 10% neutral buffered formalin or glutaraldehyde and processed for light microscopy and scanning electron microscopy, respectively. Immunohistochemical staining was performed in some cases to confirm the presence of foam cells, smooth muscle cells and endothelial cells. A semiquantitative analysis of particulate bulk was performed. Particulate matter examined by scanning electron microscopy was measured in its major and minor access and the resultant two dimensional area, calculated. This suspended particulate matter may play a role in the pathogenesis of distal emoblization, no-reflow, infarction, and morbidity and mortality following vein graft intervention.
Tables 1 and 2 below show the results of quantitative analyses performed on vein graft aspirates. Table 1 shows the frequency of acellular plaque material in vein graft aspirates. Table 2 shows the frequency of cellular plaque material in vein graft aspirates. Values are expressed as the frequency of positive samples per case. Numbers in parentheses represent the percentage of positive samples.
One preferred embodiment for a catheter for use in the preferred method is shown in
Catheter 10 generally comprises an elongate flexible tubular body 18 extending between a proximal control end 12 and a distal functional end 14. Tubular body 18 has a central lumen 40 which extends between ends 12 and 14. Lumen 40 has an opening 23 at proximal end 12, and is sealed fluid tight at distal end 14. The length of tubular body 18 may be varied considerably depending upon the desired application. For example, where catheter 10 is to be used as a guidewire for other catheters in a conventional percutaneous transluminal coronary angioplasty procedure involving femoral artery access, lengths of tubular body 18 in the range of from about 120 to about 300 centimeters are preferred, with a length of about 180 centimeters often being used. Alternately, for a different treatment procedure, not requiring as long a length of tubular body 18, shorter lengths of tubular body 18 may be provided.
Typically, tubular body 18 will have a generally circular cross-sectional configuration with an outer diameter within the range of from about 0.010 inches to 0.044 inches. Optimally, in most applications where catheter 10 is to be used as a guidewire for other catheters, the outer diameter of tubular body 18 ranges from 0.010 inches to 0.038 inches, and preferably is 0.020 inches in diameter or smaller, more preferably 0.014 inches in outer diameter or smaller. The diameter of lumen 40 will be dictated, in part, by the outside diameter of tubular body 18. For example, where tubular body 18 has an outer diameter of 0.014 inches, central lumen 40 may have an inner diameter of from about 0.008 inches to about 0.010 inches. The diameter of lumen 40 should be large enough to incorporate the low profile valve described below, and large enough to permit sufficient fluid passage for balloon inflation.
Noncircular cross-sectional configurations of lumen 40 can also be adapted for use with the low profile valve described in a preferred embodiment of the present invention. For example, triangular rectangular, oval, and other noncircular cross-sectional configurations are also easily incorporated for use with present invention, as will be appreciated by those of skill in the art. The manner of adapting the valve of the present invention will become readily apparent in view of the description which follows.
In the preferred embodiment, the tubular body 18 functions as a guidewire, and thus, tubular body 18 must have sufficient structural integrity, or “pushability,” to permit catheter 10 to be advanced through vasculature to distal arterial locations without buckling or undesirable bending of tubular body 18. It is also desirable for tubular body 18 to have the ability to transmit torque, such as in those embodiments where it may be desirable to rotate tubular body 18 after insertion into a patient. A variety of biocompatible materials, known by those of skill in the art to possess these properties and to be suitable for catheter manufacture, may be used to fashion tubular body 18. For example, tubular body 18 may be made of stainless steel, or may be made of polymeric materials such as nylon, polyamide, polyimide, polyethylenes, or combinations thereof. In one preferred embodiment, the desired properties of structural integrity and torque transmission are achieved by forming tubular body 18 out of an alloy of titanium and nickel, commonly referred to as nitinol. In a more preferred embodiment, the nitinol alloy used to form tubular body 18 is comprised of about 50.8% nickel and the balance titanium, which is sold under the trade name Tinel (TM) by Memry Corp. It has been found that a catheter tubular body having this composition of nickel and titanium exhibits great flexibility and improved kink resistance in comparison to other materials. One preferred embodiment of tubular body 18 is disclosed in our copending application entitled HOLLOW MEDICAL WIRES AND METHODS OF CONSTRUCTING SAME, application Ser. No. 08/812,876, filed on Mar. 6, 1997, the entirety of which is incorporated herein by reference.
The distal end 14 of catheter 10 is provided with an atraumatic distal tip 16, and an inflatable balloon 20, as illustrated in
As shown in
The low profile valve may be used with catheters such as that described above, all well as with different catheters having different structures. In one preferred embodiment, the low profile valve comprises a sealing member which is movably positioned within the inner lumen of a catheter. The catheter has an inflation port, which, in some embodiments, is also an opening to the inner lumen at the proximal end of the catheter. An inflatable balloon is positioned on the distal end of the catheter, which is in fluid communication with the lumen and inflation port. The sealing member is inserted through the proximal opening into the lumen, with a portion of the sealing member extending outwardly from the proximal end of the catheter. The portion of the sealing member inserted into the lumen has a sealer portion which forms a fluid tight seal with the inner lumen to prevent fluid from passing past the sealer portion.
By application of a pushing or pulling force on the extending sealing member portion, the sealing member may be partially advanced within or withdrawn from the lumen, thereby moving the sealer portion within the lumen. In this manner, the sealer portion may be positioned within the lumen either proximally or distally of the inflation port. When the sealer portion is positioned proximally of the port, the valve is in the “open” position. When the valve is open, an unrestricted fluid pathway is established between the inflation port and the balloon, such that an external pressurized fluid source may be connected to the inflation port to inflate the balloon, or if the balloon is already inflated, the balloon may be deflated by application of a vacuum to the inflation port to withdraw fluid from the balloon. When the sealer portion is positioned distally of the inflation port, the valve is in the closed position, as the fluid tight seal between the lumen and the sealer portion prevents fluid from passing either to or from the balloon through the inflation port. Furthermore, when the valve is closed after balloon inflation, the fluid tight seal created by the sealer portion maintains the balloon in the inflated state in the absence of an external fluid source, by preventing the pressurized fluid within the balloon from escaping.
Sealing member 30 comprises a main shaft 33, a tapering region 31, and a wire 32. Sealing member 30 may be formed as solid piece out of suitable metals, such as stainless steel, nitinol and the like. For example, sealing member 30 may be formed as a solid cylindrical piece, and then be coined down at points along its length to form tapering region 31 and wire 32. Alternately, one or more of the main shaft 33, tapering region 31, or wire 32 may be formed separately, and then attached to the other piece(s) by conventional means, such as soldering, to form sealing member 30. Polymeric materials, such as Delron™, nylon, and the like, may also be used to form sealing member 30, either as a solid piece, or as separate pieces which are later joined to form the sealing member.
Although not required, in one preferred embodiment, main shaft 33 has an outer diameter no larger than the outer diameter of the catheter tubular body 18. Thus, if the outer diameter of tubular body 18 is 0.014 inches, the diameter of main shaft 33, and thus the largest diameter of sealing member 30, is no larger than 0.014 inches. Furthermore, it is also preferred that main shaft 33 extend proximally from opening 23 by a distance of at least several centimeters to facilitate the application of longitudinal forces on main shaft 33 to manipulate the position of wire 32 in lumen 40. Moreover, after catheter 10 has been fully inserted into a patient, an extending main shaft 33 advantageously functions much like a conventional guidewire extension, providing a starting point for the clinician to insert other catheters over main shaft 33 and catheter 10.
The combined length of catheter 10 and extending main shaft 33 may be varied considerably at the point of manufacture, and may be adapted to the requirements of the other catheters which are to be used with catheter 10 and main shaft 33. For example, where catheter 10 is to be used as a guidewire for other catheters in an “over-the-wire” embodiment, it is preferred that the total length of catheter 10 with extending main shaft 33 be about 300 centimeters. Alternately, when catheter 10 is to be used as a guidewire for other catheters in a single operator embodiment, or “RAPID-EXCHANGE” embodiment, it is preferred that the total length of catheter 10 with extending main shaft 33 be about 180 centimeters. As can be readily appreciated, the individual lengths of catheter 10 and extending main shaft 33 can be varied considerably and yet still achieve the overall desired combined length. For example, a catheter 10 having a length of 180 centimeters can be provided with an extending main shaft 33 having a length of 120 centimeters, to achieve the 300 centimeter total desired length for over-the-wire embodiments.
In another embodiment, where it is undesirable to have a long main shaft extending proximally from catheter 10, a main shaft extending proximally only several centimeters may be provided. The shorter main shaft may be provided with an attachment (not shown), which is adapted to releasably secure longer extensions to the main shaft, such that it can also be used to facilitate the use of catheter 10 as a guidewire for other catheters.
It is preferred that main shaft 33 have a larger diameter than the other portions of sealing member 30, to make it easier to apply moving forces to sealing member 30. Thus, a tapering region 31 may be disposed between main shaft 33 and wire 32, to transition the outer diameter of sealing member 30 from the larger diameter of main shaft 33 to the smaller diameter of wire 32. For the embodiment illustrated in
In a preferred embodiment, wire 32 and catheter 10 are provided with positive stops to prevent the withdrawal of wire 32 from the proximal end of catheter 10. For the embodiment depicted in
Rings 34 and 35 may be formed of any material which may be attached to wire 32 and lumen 40, respectively, and which possesses sufficient structural rigidity to act as a stop. Examples of suitable materials are metals and various hard polymers, such as stainless steel and Teflon™. In one preferred embodiment, where wire 32 and tubular body 18 are both formed of nitinol, rings 34 and 35 are also formed of nitinol and are soldered to wire 32 and the inner surface of lumen 40, respectively.
As will be appreciated by those of skill in the art, cooperating stopping structures other than those described herein may also be used to prevent full withdrawal of wire 32 from catheter 10. For example, annular ring 34 may be replaced by one or more protrusions extending radially outwardly from wire 32, which are also adapted to cooperate with ring 35 to prevent withdrawal of wire 32. Alternately, annular ring 35 might be replaced by crimping tubular body 18 slightly to restrict movement of ring 34 to points proximal of the crimp.
A lumen sealer portion 36 is coaxially and fixedly mounted on wire 32. Sealer portion 36 is positioned on wire 32 at a point distal to ring 34, such that by partial withdrawal of wire 32 from catheter 10, as depicted in
It is preferred that sealer portion 36 form a fluid tight seal with the outer diameter of wire 32 and the inner diameter of lumen 40, such that fluid in lumen 40 is prevented from flowing past sealer portion 36. In the embodiment illustrated in
Sealer portion 36 must also be capable of maintaining a seal at fluid pressures conventionally used to inflate catheter balloons, and should be capable of maintaining a seal at pressures which exceed conventional inflation pressures. Preferably, sealer portion 36 is capable of maintaining a seal at pressures up to about 10 atmospheres, more preferably pressures up to about 30 atmospheres, and most preferably at pressures up to about 60 atmospheres. Sealer portion 36 is also preferably capable of undergoing multiple valve-opening and valve-closing cycles without losing the structural integrity required to form seals capable of withstanding pressures of from about 10 atmospheres to about 60 atmospheres. Optimally, sealer portion 36 is capable of undergoing at least 10, and preferably at least 20, valve-opening and closing events and still be capable of maintaining a fluid tight seal at a pressure of 10 atmospheres.
In one embodiment, the desired properties of sealer portion 36 are attained by forming sealer portion 36 out of an extruded polymeric tubing. Pebax™ tubing having an inner diameter of 0.008 inches and an outer diameter of 0.017 inches, and a hardness of 40 durometers, is first necked by heating the extruded tubing to a temperature of between 210 and 250 degrees Fahrenheit. Tube pieces of about 0.5 mm in length are then cut from the larger tubing. The cut Pebax™ tubes are then placed on a nitinol wire having an outer diameter of about 0.006 inches, and are heated and shaped to recover a tube that has an outer diameter of between 0.010-0.011 inches. The adhesive Loctite 4014™ may then be used to bond the heat-shaped Pebax™ tubing to the nitinol wire. When the adhesive dries, the leading and trailing edges of the bound Pebax™ seal may be trimmed, leaving an annular lumen contact length of about 0.010 inches (0.25 mm). The wire bearing the Pebax™ sealer portion may then be inserted into the opening of a nitinol catheter having a lumen with an inner diameter of about 0.0096 inches. Sealer portions of this type have been observed to hold pressures of up to 30 atmospheres, and are capable of undergoing multiple valve-opening and closing events without significantly diminishing the seal strength.
As will be appreciated by those of skill in the art, different forms of Pebax™ starting materials may be used to form sealer portion 36. For example, in another preferred embodiment, similar steps were used with a Pebax™ tube having similar dimensions but a hardness of 70 durometers, to create a sealer portion.
It is contemplated by the present inventors that methods and materials other than those described above may be used to make a lumen sealer portion having the desired properties. For example, materials other than Pebax™, silicone, latex rubber, C-Flex™, Nusil™ and gels, which are known to possess adequate surface properties to function as a sealer portion, and also be lubricous enough to be moved within lumen 40, may also be used to form sealer portion 36. In addition, sealer portion 36 may be attached to wire 32 by alternate means, such as by integrally molding sealer portion 36 to wire 32, dip forming sealer portion 36 to wire 32, as well as other means of attaching a polymeric material to a wire known to those of skill in the art.
Other embodiments of sealer portion may not create a completely fluid tight seal between the sealer portion and the inner lumen at balloon inflation pressures. In these embodiments, however, the sealer portion creates a seal which prevents substantially all inflation fluid flow past the sealer portion, such that the inflatable occlusive device is maintained in an almost fully expanded state for extended periods of at least one minute, preferably 2 or more minutes, more preferably at least 10 minutes, and optimally at least 20 minutes or longer, and still be capable of providing clinically effective occlusion of any emboli particles in the blood vessel during this time period.
In a preferred embodiment, there is provided movement-force increasing structure, to increase the force required to move sealer portion 36 from the valve-closed to the valve-open position. Structure of this type advantageously minimizes the risk of an accidental opening of the valve, and subsequent balloon deflation, during a medical procedure. In the embodiment illustrated in
A sealing member 130 is inserted into lumen 140 through opening 123, as described previously. Sealing member 130 comprises a sealer portion 136, a wire 132, annular rings 134 and 135, and support member 150. Sealing member 130 may be formed out of materials and by methods as described previously.
As illustrated in
Cooperating positive stops, consisting of hollow cylinders 134 and 135 are provided to prevent withdrawal of sealing member 130 from lumen 140. Hollow cylinder 135 is attached to the inner surface of lumen 140 by adhesives, soldering, crimping, or by other means known to those of skill in the art, such that the proximal portion of hollow cylinder 135 extends within lumen 140, and is secured therein, and the distal portion of cylinder 135 extends from proximal end 112. Cylinder 135 has a lumen (not shown) extending therethrough. The diameter of the cylinder lumen is larger than the outer diameter of wire 132, so that movement of wire 132 is not restricted. A second hollow cylinder 134, preferably of shorter length, is placed over wire 132 and is fixedly mounted to wire 132, by soldering, or other means, at a point distal to cylinder 135. The outer diameter of cylinder 134 is less than the inner diameter of lumen 140, so as not to restrict the movement of wire 132 within lumen 140. However, the outer diameter of cylinder 134 is greater than the inner lumen diameter of cylinder 135, so that cylinders 134 and 135 act as cooperating stops, to prevent wire 132 from being withdrawn from lumen 140. Cylinders 134 and 135 may be formed of any material which may be attached to wire 132 and lumen 140, respectively, and which possesses sufficient structural rigidity to act as a stop. Examples of suitable materials are metals and various hard polymers, such as stainless steel, Teflon™, and the like. In one preferred embodiment, where wire 132 and tubular body 118 are both formed of nitinol, cylinders 134 and 135 are also formed of nitinol, and are soldered to wire 132 and the inner surface of lumen 140, respectively.
The distal portion of cylinder 135 extending from proximal end 112 is inserted into support member 150. Support member 150 comprises a tubular body 158 having an outer diameter and inner lumen diameter which are approximately the same as tubular body 118. Consequently, because the outer diameter of cylinder 135 is less than the inner lumen diameter of support member 150, the extending portion of cylinder 135 is slidably disposed within the support member 150 inner lumen.
Wire 132 extends proximally from cylinder 135 within support member 150, as shown in
As illustrated in
Catheter 400 has a proximal end 412, and a distal end (not shown) to which is mounted an inflatable balloon. A central lumen 440 extends within tubular body 418 between the proximal and distal ends. An opening 423 to lumen 440 is present at the proximal end 412 of catheter 400.
A sealing member 430 is inserted into lumen 440 through opening 423. Sealing member 430 has a main shaft 433, a tapering region 431, and a wire 432. Sealing member 430 may be formed of materials and by methods as described previously. As illustrated in
As illustrated in
A lumen sealer portion 436 is coaxially and fixedly mounted on wire 432. Sealer portion 436 forms a fluid tight seal with the outer diameter of wire 432 and the inner diameter of lumen 440, such that fluid introduced into lumen 440 through opening 423 is prevented from flowing past sealer portion 436 when sealer portion 436 is inserted into lumen 440. Sealer portion 436 forms the fluid tight seal by firmly contacting the entire inner circumference of a section of lumen 440 along a substantial portion of the length of sealer portion 436, and may be formed of materials and by methods as previously described.
In some removable sealing member embodiments, the sealing member is not provided with a separate sealing portion, as described above. In these embodiments, the sealing member itself functions as a sealing portion which is inserted into the proximal opening to restrict fluid flow, and which may be partially or wholly removed to provide for a fluid pathway between the proximal opening and an expandable member on the distal end of the catheter. Preferably, the sealing members of these embodiments comprise a tapering rod, which at its distal end, has an outer diameter smaller than the inner lumen diameter of the catheter in which it is inserted as a plug, such that the distal end of the rod may be easily inserted into the catheter lumen through the proximal opening. The tapering rod increases in outside diameter at points proximal to the distal end. Consequently, one or more points of the rod have an outside diameter greater than the inner lumen diameter of the catheter in which it is inserted as a plug, such that by forcing the rod into proximal opening, the larger outer diameter of the rod forms a relatively fluid tight seal with the catheter lumen at the proximal opening of the catheter. An O-ring, or other polymeric structure, may be mounted in the inner lumen of the catheter at or near the proximal opening, to cooperate with the tapering rod in the creation of the seal. Thus, in this embodiment, the point where the seal is created does not move with respect to the catheter, but is instead stationary at or near the proximal opening of the catheter.
A sealing member 550 is positioned within lumen 540 near proximal opening 523 and side-access port 522. Sealing member 550 is formed from a short tubular body 568, having a lumen 590, which is sealed at end 562, but open at the other end. Sealing member 550 has, an outer diameter slightly larger that the inner diameter of lumen 540, but smaller than the outer diameter of tubular body 518, such that sealing member 550 may be tightly fit within lumen 540 through opening 523, to form a fluid tight seal over catheter proximal opening 523. Cooperating stopping structures (not shown) may be provided to sealing member 550 and catheter 500 to prevent removal of sealing member 550 from lumen 540 at elevated pressures. Sealing member 550 may be formed out of the same materials as tubular body 518.
Tubular body 568 is provided with an opening 572 extending therethrough. Opening 572 is positioned on tubular body 568 such that opening 572 is capable of aligning with side-access port 522 when sealing member 550 is rotated within lumen 540, or is moved proximally or distally within lumen 540. A rotation element 595, such as a perpendicular attachment, may be provided facilitate rotation of sealing member 550 within lumen 540. Other rotation elements, such as notches or grooves, may be used in place of the perpendicular attachment, as will be appreciated by those of skill in the art.
Sealing member 550 functions as a valve within catheter 500, controlling fluid flow through side-access port 522. When sealing member 550 is rotated so that port 522 and opening 572 are aligned, fluid may flow through port 522 through lumen 540 to inflate the occlusive device. Upon the desired inflation, sealing member 550 may be rotated, as for example by ninety degrees, or moved proximally or distally within lumen 540, such that opening 572 is no longer aligned with port 522, and tubular body 568 blocks fluid flow through port 522.
In certain embodiments, it may be desirable for sealing members 550 and 650 to have a longer length, such that they may function as an extension for other catheters to be inserted over catheters 500 and 600. In these embodiments, sealing members 550 and 650 may be formed with longer tubular bodies, or be provided with attachments so that extension members may be releasably secured thereto.
A wire 732 is inserted into opening 723, and is slidably disposed within lumen 740. Accordingly, the outer diameter of the wire 732 must be less than the inner diameter of lumen 740, so that wire 732 may be slidably accommodated therein. A sealer portion 736 is coaxially mounted on wire 732. Sealer portion 736 is of similar type and construction to the sealer portion described in connection with
In the embodiment depicted in
In a preferred embodiment, tubular body 718 is made out of nitinol, and has at least 8% elasticity when longitudinal slits 711 are introduced at the proximal end. As can be observed in
A groove 240 separates first half 202 from second half 204 when the halves are closed and clip 230 is secured. Groove 240 is of sufficient width to accept the proximal end of a catheter having the low profile valve, as described in detail above. A fitting 210 is positioned on half 202, to create an inflation passageway 212 which terminates in opening 285 on the interior surface of first half 202. Fitting 210 is preferably a standard luer connector which may be attached to a variety of existing external pressurized fluid sources, although other types of fittings, such as tubings, quick connects, and Y-site connections, may be easily substituted for a luer fitting.
A seal comprising a pair of gaskets 280 is positioned around opening 285 on the interior surfaces of halves 202 and 204. Gaskets 280 are in alignment, such that when halves 202 and 204 are brought together and secured by locking clip 230, a fluid tight inflation chamber is created within the interior region defined by gaskets 280. The fluid tight inflation chamber is in fluid communication with fitting 210 via inflation passageway 212, so that a pressurized inflation fluid may be introduced into the fluid tight inflation chamber by attaching an external pressurized fluid source to fitting 210. Moreover, gaskets 280 are preferably formed of resilient materials, such as silicone, C-Flex™ and Pebax™, so that gaskets 280 may form-fit over a catheter tubular body which extends across the lateral edges of gaskets 280, to create the fluid tight chamber.
An actuator 220 is positioned on the external surface of half 202. In the embodiment illustrated in
Panels 283 and 284 each have a roughened surface 290, to facilitate the frictional engagement of panels 283 and 284 with the main shaft portion of the low profile valve. In a preferred embodiment, panels 283 and 284 are both made of silicone, and roughened surface 290 comprises teeth 291 and grooves 292 formed on each of panels 283 and 284. The teeth 291 and grooves 292 cooperate, to permit the teeth of one panel to fit into the grooves of the opposite panel when the adaptor is closed.
For ease of understanding, the operation of inflation adaptor 200 to inflate the balloon of the catheter of
As shown in
Indicia solely on the catheter tubular body may also be used to facilitate correct alignment. For example, two visible markings may be place on the catheter on either side of the catheter inflation access port. By inserting the catheter into lower half 204 so that both of these markings are place within lower half gasket 280, the catheter inflation access port will be within the fluid tight inflation chamber created by gaskets 280 when halves 202 and 204 are secured to one another.
Once main shaft 33 and inflation port 22 are properly aligned within adaptor 200, locking clip 230 is secured. Inflation port 22 now lies within the fluid tight inflation chamber created by gaskets 280, and main shaft 33 rests between sliding panels 283 and 284. The clinician may then attach an external pressurized fluid source to fitting 210.
To inflate balloon 20, the clinician moves actuator 220 from the first position to the second position, thereby causing sliding panels 283 and 284 to move away from opening 285. Because main shaft 33 is firmly secured between panels 283 and 284, a longitudinal force directed away from proximal end 12 is applied to main shaft 33. The longitudinal force on main shaft 33 results in wire 32 being partially withdrawn from lumen 40, which causes sealer portion 36 on wire 32 to be moved to a position within lumen 40 which is proximal of inflation port 22. The movement of sealer portion 36 proximally of inflation port 22 opens the low profile valve, by establishing an unrestricted fluid pathway between inflation port 22 and balloon 20.
The external pressurized fluid source may then be activated, as for example by pushing the plunger on a syringe, such that pressurized fluid passes through passageway 212 and opening 285 into the fluid tight inflation chamber. The pressurized fluid then passes through inflation port 22 and lumen 40, to inflate balloon 20.
Inflated balloon 20 may be maintained in the inflated state, in the absence of the pressurized fluid source, by closing the low profile valve. This is accomplished by moving actuator 220 back to the first position, thereby causing sliding panels 283 and 284 to move toward opening 285. The moving panels apply a longitudinal force, directed toward proximal end 12 to main shaft 33, causing wire 32 to be further inserted into lumen 40. Consequently, sealer portion 36 is moved from a position, within lumen 40 which is proximal to inflation port 22 to a position in lumen 40 which is distal to inflation port 22. The fluid tight seal created by sealer portion 36 traps the pressurized fluid within lumen 40 and balloon 20, thereby maintaining balloon 20 in the inflated state. The external pressurized fluid source may then be deactivated and removed. Once the low profile valve is closed, inflation adaptor 200 may be removed by unlocking clip 230, and removing catheter 10 and main shaft 33 from groove 240.
Adaptor 300 comprises an outer sleeve 320 formed of metal, medical grade polycarbonate, or similar such materials. Outer sleeve 300 defines a tapering inner lumen 350. Lumen 350 tapers from large diameter 352 which is significantly greater than the outer diameter of the catheter tubular bodies inserted into lumen 350, to a smaller diameter 355, which is slightly larger the outer diameter of the catheter tubular body. Lumen 350 is in fluid communication with an inflation passageway 312 formed by fitting 310, so that a pressurized inflation fluid may be introduced into lumen 350. Releasable seals 315 are positioned at each end of lumen 350, such as to create a fluid tight inflation chamber within lumen 350 when a pressurized fluid source is attached. Releasable seals 350 may comprise any type of seal known to those of skill in the are, such as Toughy Borst connectors, hemostatic valves, and the like. Releasable seals 350 may also act to secure any catheters and sealing members inserted within the releasable seal openings 325
In use, a catheter and sealing member, such as that described in connection with
Halves 802 and 804 are attached to one another by hinges 806 positioned on one of the lateral edges of each half, through which a joining pin 805 is inserted, such that halves 802 and 804 may be opened or closed in a clam shell manner as depicted in
As shown in
Cam latch 830 is designed to secure halves 802 and 804 together when adaptor 800 is in use, to assist in the creation of an the inflation seal as described above. Advantageously, by placing cam latch on half 804 as shown, the adaptor interior is more accessible to the clinician during a procedure, and it is easier for the clinician to insert catheters into adaptor 800. Cam latch 830 also serves the important function of preventing accidental opening of the adaptor 800 during use. An important feature of cam latch 830 is the manner in which it cooperates with housing half 802 to create a releasable locking mechanism which applies great force to halves 802 and 804 upon closing, while at the same time using the principles of mechanical advantage to minimize the force the user must exert to close cam latch 830. This is achieved by providing latch 830 with a cammed surface 838 and also providing the front edge of housing half 802 with a rounded lip 837 to accept cammed surface 838, as shown in cross-sectional schematic form in
Cam latch 830 is also preferably provided with a shelf 835 to secure halves 802 and 804 together. Shelf 835 is positioned on latch 830 at a point such that when latch 830 is in its closed position, shelf 835 firmly contacts housing half 802 along the side bearing hinges 806. Preferably, shelf 835 has an angled leading edge to facilitate closing of latch 830.
A gap 840 separates first half 802 from second half 804 when the halves are closed and latch 830 is secured. Gap 840 is of sufficient width to accept the proximal end of a catheter having the low profile valve, as described in detail above, without crimping the catheter to impair its function. A fitting 810 is positioned on half 802, to create an inflation passageway 812 which terminates in opening 885 on the interior surface of first half 802. Fitting 810 is preferably a standard luer connector which may be attached to a variety of existing external pressurized fluid sources, although other types of fittings, such as tubings, quick connects, and Y-site connections, may be easily substituted for a luer fitting.
A seal comprising a pair of gaskets 880 is positioned around opening 885 on the interior surfaces of halves 802 and 804. Gaskets 880 are in alignment, such that when halves 802 and 804 are brought together and secured by cam latch 830, a fluid tight inflation chamber is created within the interior region defined by gaskets 880. The fluid tight inflation chamber is in fluid communication with fitting 810 via inflation passageway 812, so that a pressurized inflation fluid may be introduced into the fluid tight inflation chamber by attaching an external pressurized fluid source to fitting 810. Gaskets 880 are preferably formed of resilient materials, such as silicone, C-Flex™ and Pebax™ or Kraton™, silicone, and other elastomeric materials, so that gaskets 880 may form-fit over a catheter tubular body which extends across the lateral edges of gaskets 880, to create the fluid tight chamber.
An actuator 820 is positioned on the external surface of half 802. In the embodiment illustrated in
Sliding panel 883 moves back and forth along a line which bisects opening 885. When actuator 820 is moved to a first position, shown in
In actual clinical practice, the movement of panels 883 and 884 results in the opening and closing of a catheter valve placed within adaptor 800. When actuator 820 is moved to the position shown in
Adaptor 800 is also preferably provided with a safety lock, to prevent accidental opening when the adaptor is being used and the catheter valve is open. As shown in
Panels 883 and 884 each have a roughened surface 890, to facilitate the frictional engagement of panels 883 and 884 and their coordinated travel with the moving portions of the low profile valve. Panels 883 and 884 may be made from any of a variety of polymeric or metallic materials, but must possess sufficient frictional force to engage and move the catheter sealing member without slippage. Consequently, depending on the type of catheter used, those of skill in the art may desire to select different materials for panels 883 and 884 to maximize the frictional forces between the panels and their intended use catheter. In a preferred embodiment, in which panels 883 and 884 are to engage a catheter sealing member made from stainless steel, panels 883 and 884 are both made of Kraton 90A™, and roughened surface 890 comprises teeth 891 and grooves 892 formed on each of panels 883 and 884. The teeth 891 and grooves 892 cooperate, to permit the teeth of one panel to fit into the grooves of the opposite panel when the adaptor is closed. Furthermore, alternative cooperating structure, such as dimples and ridges, may also be used to coordinate travel of panels 883 and 884.
One problem that has been recognized with low profile valves is the phenomenon of plug walk-out. That is, after the valve has been placed in its closed position, with the sealer portion of the sealing member distal to the inflation access port, and the adaptor removed, the internal forces on the sealing member tend to cause very small portions of the sealing member to be pushed out of the catheter proximal end. Plug walk out is undesirable as it has an adverse impact on the ability of the sealed catheter to act as a guidewire for other devices. It has been found, however, the plug walk out can be minimized or eliminated if the sealing member is initially “overdriven”, or forced slightly further in the catheter, during the sealing step.
Advantageously, adaptor 800 is provided with an overdrive system to overdrive a sealing member into a catheter. Referring to
When a catheter with a valve in a closed position is loaded into half 804, and halves 802 and 804 are closed and latched, the teeth 891 of panel 883 contact the grooves of panel 884. The superior spring force of spring 888 then forces spring 809 to compress a small amount, such that panel 884 no longer is forced against the recess wall, and now has an overdrive gap (not shown) approximately equal to overdrive gap 886. The actuator may then be engaged to drive panels 883 and 884 away from opening 885 toward recess walls 893 a and 894 a, respectively, thereby opening the valve mechanism. The inflatable balloon on the catheter may then be inflated as described above.
Upon closure of the valve, by rotating actuator 820 in the opposite direction, panels 883 and 884 are moved toward opening 885 until the sealer portion of the sealing member is distal to the catheter inflation access port. Overdrive of the sealing member is then achieved when actuator 820 is adjusted so that panels 883 and 884 are forced against recess walls 893 b and 894 b, as shown for panel 883 in
Alternative overdrive mechanisms may be used for other adaptor embodiments. For example, rather than mounting spring 888 on panel 883, the spring might be mounted in a slot wall 893 b, with a plunger (not shown) attached to panel 883 and aligned with the spring. In its unforced state, the spring would exert force on the plunger, pushing panel 883 away from wall 893 a to create overdrive gap 896. However, as before, the actuator mechanism 820 could be used to overcome the spring force in the valve closing cycle, thereby creating the overdrive. Numerous other overdrive mechanisms may also be employed, as will be appreciated by those of skill in the art.
As illustrated in
It is also preferred that half 804 be provided with guiding means to facilitate correct positioning of the catheter into the adaptor. For the embodiment illustrated in
Alternately, other guiding means may be used as well. For example, clips 896 may comprise one or more magnetic elements which cooperate with gold-plated stainless steel rings (or other plated ferromagnetic substances) incorporated into the catheter tubular body to guide the catheter into the correct alignment position.
In one preferred embodiment, as shown in
In clinical practice, there is a direct correlation between the distance that panel 884 moves and the distance moved by the sealer portion of a catheter valve when adaptor 800 is used. Consequently, a controlled and known movement of panel 884 over a set direction and distance results in a movement of the valve sealer portion in the same direction and for substantially the same distance. Thus, with a controlled movement adaptor such as adaptor 800, there is no need to require a catheter having positive cooperating stops to prevent removal of the sealer portion from the catheter, as was described for the catheter of
Accordingly, in one preferred embodiment, adaptor 800 is used with catheter 900, which lacks positive cooperating stops, and is depicted in
Catheter 900 has a proximal end 912, and a distal end (not shown) to which is mounted an inflatable balloon. A central lumen 940 extends within tubular body 918 between the proximal and distal ends. An opening 923 to lumen 940 is present at the proximal end 912 of catheter 900. A side-access port 922 in fluid communication with lumen 940 is provided on tubular body 918.
A sealing member 930 is inserted into lumen 940 through central lumen opening 923. Sealing member 930 has a first region 935 which has an outer diameter substantially the same as the outer diameter of the proximal end 912 of catheter tubular body. Region 935 has a taper 934, reducing in diameter to a second region 933 which has an outer diameter less than the inner diameter of lumen 940. Region 933 tapers over length 931 to form a plug mandrel wire 932. As a consequence, region 933 and plug mandrel wire 932 are slidably insertable into the proximal opening 923 of catheter 900 and may freely move within lumen 940. In one preferred embodiment, region 935 has an outer diameter of about 0.013 inches, region 933 has an outer diameter of about 0.0086 inches, and plug mandrel wire has a diameter of about 0.005 inches, with region 933 and plug mandrel wire 932 being inserted into a catheter having a central lumen 940 with an inner diameter of about 0.009 inches.
The length of sealing member region 935 extending proximally of catheter 900 may vary in length depending upon the intended use environment. For example, where catheter 900 is to be used as a guide for other catheters in an “over-the-wire” embodiment, it is preferred that the total length of catheter 900 and sealing member region 935 be about 300 centimeters. Alternately, where catheter 900 is to be used in a single operator or rapid exchange embodiment, it is preferred that the total length of catheter 900 and region 935 be about 180 centimeters. Accordingly, with a known catheter length and use environment, an appropriate length for region 935 may be chosen.
The elements of sealing member 930 may be formed of materials and by methods as described previously. For example, regions 935 and 933 and plug mandrel wire 932 may all be made out of metals such a stainless steel. Alternately, combinations of materials may be used as well. For example, in some applications it may be desirable to manufacture regions 935 and 933 out of stainless steel, while manufacturing plug mandrel wire 932 out nitinol. Furthermore, the various sealing member regions may be made from a single metal wire strand coined at various points to achieve the desired dimensional tolerances, or multiple segments may be joined together to form sealing member 930.
Where multiple segments are joined, region 935, region 933, and plug mandrel wire 932 are attached to one another by any suitable means of bonding metal to metal, such as soldering, brazing, adhesives and the like. In one preferred embodiment, cyanoacrylate adhesives are used to adhere these various parts of sealing member 930 to one another.
As illustrated in
As illustrated in
A lumen sealer portion 936 is coaxially and fixedly mounted on wire 932. Sealer portion 936 forms a fluid tight seal with the outer diameter of wire 932 and the inner diameter of lumen 940, such that fluid introduced into lumen 940 through side-access port 922 is prevented from flowing past sealer portion 936 when sealer portion 936 is inserted into lumen 940 distally of side-access port 922. Sealer portion 936 forms the fluid tight seal by firmly contacting the entire inner circumference of a section of lumen 940 along a substantial portion of the length of sealer portion 936, and may be formed of materials and by methods as previously described.
As shown in
Catheter 900 is changed from the valve open position to the valve closed position by the movement of sealing member 930 and its various components. Preferably, the exact length of movement needed to change catheter 900 from the valve closed to the valve open position is built into the movement function of the adaptor used to manipulate sealing member 930 thereby opening and closing the catheter valve. In this regard, it is preferred that catheter 900 be used with an adaptor such as adaptor 800, which provides for such controlled precise movement.
The “stroke-length”, or overall movement in one dimension, of sealing member 930 required to open or close the valve may be varied depending upon the catheter requirements. When relying upon the inflation adaptor to control movement, however, it is important that the movement of the controlling elements of the adaptor be coordinated with those of sealing member 930. With respect to adaptor 800, this is accomplished by selecting a recess 893 dimension which precisely defines the distance that sealing member 930 is to travel to achieve the valve open and valve closed positions, without accidentally removing sealing member 930 from opening 923. In one embodiment, where access port 922 is positioned 36 mm from opening 923, a stroke length of 5.5 mm was found to be suitable.
III. Expansion Members
The expansion members discussed herein include braids, coils, ribs, ribbon-like structures, slotted tubes, and filter-like meshes. These expansion members may be partially covered or completely surrounded by a membrane or other covering to provide occlusion or sealing of the vessel. As used herein, “occlusion” or “sealing”, and the like, mean partial or complete blockage of fluid flow in a vascular segment, as it is sometimes preferable to allow perfusion. Moreover, such expansion members may be deployed by various mechanical means, electrical means or thermomechanical means, etc., as described herein. Expansion members that are deployed mechanically are preferably “spring-like” in nature, i.e. they are preferably resilient to facilitate their deployment or retraction.
A. Catheter Apparatuses and Self-Expanding Braids
One embodiment of a catheter apparatus incorporating the present invention for treating occluded vessels is shown in
Self-expanding sealing mechanism 1666 is mounted on the distal extremity 1654. This self-expanding sealing mechanism 1666 can take any suitable form. For example, as shown it can consist of a braided structure 1667 formed of a suitable shape memory material such as a nickel titanium alloy that will attempt to expand to a predetermined shape memory. Other than shape memory materials, other materials such as stainless steel, Elgiloy™, titanium or other materials can be utilized in the braid 1667 as long as they have the capability of expanding when the self-expanding seal mechanism is released. Also it should be appreciated that the self-expanding seal mechanism 1666 can be comprised of an absorbent material which when it absorbs saline or blood expands to form a seal. Such seals can be readily accomplished because it is only necessary to form a seal of approximately 1.5 psi to prevent small particles from moving downstream.
In order to prevent abrasion of a vessel, it is desirable to cover the braided structure 1667 with a covering 1668 of a suitable material such as a polymer or a biocompatible coating which extends over the braided structure 1667 and which moves with the braided structure 1667 as it expands and contracts. The polymer can be of a suitable material such as silicone, C-flex, polyethylene or PET which would form a good sealing engagement with the wall of the artery. The covering 1668 may be perforated to allow perfusion.
A mechanism is provided for compressing the self-expanding sealing mechanism 1666 so that the apparatus can be inserted into the vessel 1481 and consists of an elongate sleeve 1771 having proximal and distal extremities 1772 and 1773 and a bore 1774 extending from the proximal extremity 1772 to the distal extremity 1773. A collar 1776 is mounted on the proximal extremity 1772 of the sleeve 1771 and is positioned near the adaptor 1656. The collar 1776 serves as a mechanism for retracting the sleeve as shown in
Another embodiment of a catheter apparatus for treating occluded vessels incorporating the present invention is shown in
In accordance with the hereinbefore described descriptions, it is apparent that the apparatus can be readily deployed and serve the same function as the main catheter. To accomplish this, the assembly 1781 can be introduced into the femoral artery and the distal extremity advanced into the desired location in the arterial vessel. After it has been properly positioned, the physician can retract the sleeve 1796 to permit the self-expanding seal mechanism 1791 to expand and to form a seal with the wall of the arterial vessel to occlude the arterial vessel and interrupt the flow of blood in the vessel to provide a working space distal of the occlusion formed. This prevents small particles which may thereafter be dislodged from moving downstream. Since a central lumen is available, the therapeutic procedures hereinbefore described can be employed with the catheter apparatus shown in
Although the self-expanding sealing mechanism 1666 (1791) can be deployed by retracting the sleeve 1771 (1796) as previously described, the sealing mechanism can also be deployed by pushing the flexible elongate member 1652 (guiding catheter 1782) through the sleeve so that the sealing mechanism can expand. This may be the preferred way of deploying the sealing mechanism 1666 (1791), if there is little clearance between the apparatus 1651 (1781) and the vessel within which the apparatus resides, to reduce the risk of damaging the patient's vessel. As discussed below in connection with subsequent figures, the sealing mechanism 1666 (1791) may alternatively comprise members such as a coil, a ribbon-like structure, a slotted tube, or a filter-like mesh. In each case, the sealing mechanism expands to partially or completely occlude the vessel in question, or alternatively, to anchor an intravascular device to the vessel.
Furthermore, although the embodiments described in
B. Alternative Self-Expanding Members
Another embodiment using a braided structure is shown schematically in
Although the embodiment of
The membrane 1036 is preferably impervious to the flow of blood (
Alternative self-expanding media are shown in
An embodiment similar to that shown in
Another embodiment that employs a self-expanding medium is shown in
As in the other self-expanding embodiments, the self-expanding mechanism 1100 (1120) is in an unexpanded state when enclosed by the second elongate member 1108 (1126), and expands when pushed or pulled beyond the second elongate member 1108 (1126).
C. Non-Self-Expanding Embodiments
1. Heat Activated Embodiments
2. Mechanically Deployed Embodiments
Other non-self-expanding sealing mechanisms that can be used for occluding a vessel are described below. In the embodiment of
To assemble the device, the first and second ring members 1148 and 1152, the ribbons 1156, and the membrane 1160 are placed as a unit around a second elongate member 1166, which has a pair of oppositely facing holes 1170 and 1172. The brace member 1144 is inserted through the holes 1170 and 1172 and secured to both the pull wire 1140 and the first ring member 1148. Further, the second ring member 1152 is secured to the second elongate member 1166. This Assembled configuration, with the ribbons 1156 in their longitudinal orientation, is illustrated in
A preferred way of retracting the pull wire 1140 is shown in
An alternative to the deployment apparatus illustrated in
Both pull wire mechanisms shown in
Although the principle of using a non-self-expanding mechanism has been illustrated in
Other non-self-expanding mechanisms such as a filter-like mesh 1208, a slotted tube 1212, and coils 1216 can be used to form units 1220, 1230, and 1240 analogous to the braided structure unit 1204 as shown in
It should be understood that the scope of the present invention is not be limited by the illustrations or the foregoing description thereof, but rather by the appended claims, and certain variations and modifications of this invention will suggest themselves to one of ordinary skill in the art.