US 20050049696 A1
For the treatment of an insufficient cardiac valve or a cardiac valve with a stenosis, a device is provided that comprises a micro axial pump (40). The pump portion (14) of the micro axial pump carries a dilating device (18) suitable for pushing open a stenosis in a valve. The dilating device is designed as a high-pressure balloon. During dilation, the micro axial pump (40) operates so that the heart is relieved. With insufficient cardiac valves, a stent (21) is fastened to the dilating device (17), the stent surrounding a flexible cardiac valve prosthesis (20). By dilation, the stent (21) is pressed against the insufficient cardiac valve and the same is passivated. The cardiac valve of the cardiac valve prosthesis is unfolded to assume the function of the natural cardiac valve.
5. A device for intravascular cardiac valve surgery comprising a micro axial pump fastened to a catheter and having a tubular pump portion, a dilating device for expanding a stent, and a stent carrying a folded flexible cardiac valve prosthesis and being adapted to be expanded by the dilating device.
6. The device of
7. The device of
8. The device of
The invention refers to a device for intravascular cardiac surgery comprising a micro axial pump fastened to a catheter.
In WO 98/43688, an intra-cardiac blood pump is described that has a motor portion and a pump portion and can be introduced into the heart through the vascular system. Such a blood pump can be positioned in the aortal valve through the aorta, for example, to pump blood from the left ventricle into the aorta. Such blood pumps are adapted to support or replace the pumping effect of the heart. They can be positioned in the heart without requiring the heart to be opened.
From WO 97/37697, an intravascular blood pump is known that also has a motor portion and a pump portion, which are connected to a catheter. The blood pump can be pushed through the vascular system of the patient. It is a micro axial pump with a diameter of about 7 mm at most. The pump portion is surrounded by an expandable blocking device blocking the flow path outside the pump housing. Thereby, it is made sure that all blood drawn in is conveyed past the motor portion in the flow direction and short circuits caused by the flow around the pump portion are avoided. The blocking device may be an annular balloon affixed to the pump housing or an intake hose connected to the pump housing. This blood pump is intended for use in blood vessels, the blocking device only serving the purpose of blocking the vessel lumen around the pump portion, but not of deforming the vessel wall. Therefore, the balloon of the blocking device is a low pressure balloon inflated with low pressure so as to seal against the vessel wall in an non-traumatic manner.
Also known are dilating catheters having a balloon with which a vascular stenosis can be removed by pushing it open. Such dilating catheters can also be used to insert an annular stent consisting of an expandable metal structure and forming a supporting device, so as to form a permanent widening support for the stenosis. Such a dilating catheter is designed as a perfusion catheter with a pump portion for conveying blood through the inflated balloon. For cardiac valve surgery, this dilating catheter is not suitable if only for its small diameter of 2 mm at most.
The most frequent defects of cardiac valves are valvular incompetence and valves with stenoses. In case of incompetence, the valve is unable to close fully. This causes a return flow. In general, such valves have to be replaced with artificial valves. Valves with stenoses have valve leaflets grown together at the edges, whereby the valve will not open completely and does not allow the full blood flow to pass therethrough.
There are two forms of surgery on the cardiac valves: In cardiac valve replacement, the natural cardiac valve is removed and surgically replaced with a bio-prosthesis or a mechanical cardiac valve. For this type of surgery, it is necessary to keep the operating area free from blood, i.e. to divert the natural blood flow. In case of a repair of the natural cardiac valve, a minimally invasive intervention can be performed using a balloon introduced into the valve. Such operations, e.g., at the aortal valve, the cardiac surgeon or the cardiologist needs great skill. Among others, the reason for this is that the blood flow through the aorta has to be blocked during the breaking process so that the operation has to be made in very short time for the supply to the vessel system to be restored. Further, the pressure inside the heart rises extremely when blocking the aortal flow while its blood supply via the coronal vessels is halted.
It is the object of the present invention to provide a device for intravascular cardiac valve surgery with which minimally invasive valve operations can be done relatively simple and without being pressed for time.
The object is solved, according to the invention, with the features of claim 1.
In the present device, an intravascular micro axial pump is provided, i.e., a pump that can be pushed through the vascular system of a patient and has an correspondingly small outer diameter that does not exceed 8 mm. The pump portion of the micro axial pump bears a dilating device which is adapted to break up a stenosis in a cardiac valve if placed in the cardiac valve. This dilating device preferably comprises a high-pressure balloon whose expanded diameter is at least 15 mm and which is inflatable with at least 1.0 bar. The high-pressure balloon is positioned in the cardiac valve and expanded using a liquid so that it breaks or blows open a stenosis in the cardiac valve. The dilating device thus forms an active element for breaking up a stenosis in a cardiac valve, in particular a stenosis in an aortal valve or a bicuspid valve.
The lumen of the pump portion or of the cannula adjoining the pump portion is at least 8 mm so as to avoid a too strong local blood flow with large physiological volume flows of up to 7 I/min. Further, the carrier of the dilating device should have an outer diameter of at least 8 mm so that a sufficiently large support for the dilating device is formed and the extent of the diameter increase does not become excessive.
Further, the invention refers to a device for intravascularly placing a cardiac valve prosthesis according to the features of claim 5. This device is also provided with a micro axial pump bearing a dilating device. Moreover, a stent is provided carrying a flexible cardiac valve prosthesis on its inner side. The stent containing the cardiac valve prosthesis can be introduced into the pathogenic cardiac valve and can be expanded by the dilating device so that it presses the valve leaflets of the natural cardiac valve apart. This cardiac valve prosthesis includes a single- or multi-wing cardiac valve that automatically becomes functional and replaces the natural cardiac valve.
As the cardiac valve prosthesis, a jugular valve taken from calves or cows can be used. This would be a bio-prosthesis of natural tissue.
The following is a detailed description of embodiments of the invention with reference to the drawing.
In the figures:
To push open an aortal valve AK with a stenosis, the device illustrated in
An annular balloon 17 is provided on the pump portion 14 and is illustrated in
The pump device is introduced into the aorta by first placing a guiding wire (not illustrated) in the aorta and the left ventricle. Then the device is advanced along the guiding wire and positioned in the aortal valve AK such that the intake portion 16 a is within the left ventricle LV, whereas the outlet portion 19 is within the aorta. The pump portion 15 is thus enclosed by the aortal valve AK. The pump device conveys backward, i.e., it draws axially and ejects laterally in the outlet portion 19.
After the pump device has been positioned in the way illustrated in
FIGS. 3 to 7 refer to a device with which an insufficient valve is replaced with a valve prosthesis. To this end, generally the same device as described with reference to
The flexible cardiac valve prosthesis 20 is illustrated in
To avoid displacement of the cardiac valve prosthesis, the stent 21 or the cardiac valve prosthesis 20 can be fixed in the annulus 26 surrounding the natural cardiac valve. This is a strong ring of cartilage suitable for use as a holder of a cardiac valve prosthesis.