WO2007010391A1

WO2007010391A1 - Apparatus for operations of arterial hemostasis

Info

Publication number: WO2007010391A1
Application number: PCT/IB2006/002127
Authority: WO
Inventors: Luciano Alcidi; Marzia Nardiello; Gino Grassi; Franco Papa
Original assignee: Luciano Alcidi; Marzia Nardiello; Gino Grassi; Franco Papa
Priority date: 2005-07-22
Filing date: 2006-07-20
Publication date: 2007-01-25
Also published as: ITFI20050163A1

Abstract

Apparatus for arterial hemostasis, comprising a cannula (2) for the insertion, through a portion of the dermis (3), of a probe or catheter (6) sliding within said cannula and provided with means (7, 8) able to make a hemostasis of a hole (5) in the wall of an artery (4), and with at least a flow sensor (7) disposed in proximity of said hemostasis means.

Description

DESCRIPTION

APPARATUS FOR OPERATIONS OF ARTERIAL HEMOSTASIS Technical Field

The present invention relates to an apparatus and instrumentation capable of detecting with accuracy the perforation of a vascular wall and performing the hemostasis thereof.

State of the Art

It is known that in surgery operations which include the perforation of a vessel, for example in coronary diagnostic tests or in angioplasty procedures, a problem arises, at the end of the operation, of occluding the hole in the artery made by the introduction of the catheters used for the operation. At present, several procedures exist to obtain such occlusion, for example by means of biodegradable collgens that are deposited through suitable mechanical devices.

These materials, however, occlude the arterial hole only in a precariuous way, thereby rendering the procedure hardly reliable.

Alternatively, it is known to resort to the traditional suture which, however, implies an invasive and relatively complex operation.

Description of the Invention The object of the invention is to overcome the drawbacks of the prior art .

This object is achieved by providing an apparatus and instrumentation according to the attached claims.

A first advantage is given by the accuracy with which it is possible to locate the region of perforation to be occluded.

A further advantage, related to the possibility of directing cauterizing electrodes to the exact point, is given by the rapidity and efficacy with which the cauterization operates the occlusion. Moreover, according to the invention, the cauterization procedure can be rendered automatic and, therefore, immediate, by using, as a control element of RF energy activation, the variation of temperature that occurs when the electrode 7 leaves the arterial bed.

The immediacy of the cauterization allows minimizing possible hematic effusions.

The characteristics and advantages of the present invention will be more evident from the indicative, and thus non- limitative, description of one preferred, but nonexclusive, embodiment of invention, as illustrated in the accompanying drawings, wherein:

- Fig. 1 shows schematically an apparatus, according to the invention applied for the hemostasis of an arterial wall; and

- Fig. 2 illustrates a detail of the active electrode of the apparatus of Fig. 1.

- Fig. 3 is a graph showing an example of temperature detection and RF-emission performed by the apparatus of the invention.

With reference to the attached figures, an apparatus 1 according to the invention comprises a hemostasis probe 6 sliding within an introducer or cannula 2 already inserted into the vessel for the test in progress. The cannulla 2 allows introducing the probe 6 thereinside in such a way as to project from the distal end of the body 2, the probe being provided with a temperature sensor 7 located at its distal end and with RF-emitters electrodes 7, 8 disposed at a known distance from the temperature sensor 7.

The electrode 8, which represents the reference electrode of RF-energy delivery, may be replaced by a surgery plate disposed on the back of the patient. In this case, the probe 6 consists of only the temperature-sensing and RF- emitting sensor electrode 7. Preferably, the same temperature sensor 7 is made up of a thermocouple acting also as an electrode for the local delivery of radio frequency energy able to carry out the cauterization of the perforation 5. To control and activate the electrodes 7 and 8, provision is made for connections 9 and 10 to an external control unit including a radio frequency generator for controlling the power emitted by the electrode 7 and measuring the local temperature induced by the RF-generated heating. According to the invention, the thermocouple 7 is made up of metal connections 11, 12, preferably of copper- constantan combination, welded to the head of the distal electrode and connected to the instrumentation to function also as RF energy-emitting electrode for the local heating of the blood and the cauterizing operation.

The same control unit, therefore, controls the emitting power of electrode 7 during the cauterization of the hole 5 in the artery 4. Once the catheter used for the test under way has been extracted, the probe 6 is introduced into the cannula 2 so that the electrodes 7, 8 result in the arterial bed. Upon starting the generator of the control unit, the electrodes 7, 8 emit a power of 2-3 W and, as a consequence of the thermal flush within the arterial bed, the sensor 7 measures a temperature very close to the basal one. By withdrawing the cannula 2 and probe 6 as one piece, when the sensor 7 reaches the arterial hole, that is, the region 12 around the perforation 5 in which there is a condition of blood' s stagnation, the thermal flush due to the arterial flow is missing, and the measured temperature raises abruptly.

With reference to Fig. 3, the graph in this figure shows how the apparatus position can be detected and, in particular, it shows both the temperature variation measured by the sensor 7 between a region inside the axtery and the corresponding wall region outside the artery, and the relevant delivered power as a function of time upon the positioning stage.

It should be noted that the produced temperature variation can be advantageously utilized to automatically activate the delivery of power upon the cauterization procedure, preferably but not limitatively, a radio frequency delivery, to obtain the cauterization of the artery hole. It is stressed that the energy delivery for the cauterization is automatically controlled according to the cauterization temperature programmed beforehand (for example at 80/90°) .

Should the delivered power induce excessive temperature, the generator would modulate the delivered power to make it fall within the preset temeperature limits.

In this way there is obtained both an optimal discrimination of the temperature variations, as ensured by the controlled local heating, and a prompt delivery of energy necessary for closing the hole. By way of example, it has been found that a temperature increase ΔT in the absence of flow is about 8-10 degrees above the basal temperature measured in the artery and, therefore, able to be positively detected by the sensor (Fig. 3) . In this position, the sensor 7 measures therefore an abrupt increase of temperature due to the missed action of "thermal flush".

According to the invention, the extent of the temperature' s sudden rise allows the operator to know that the distal end of probe 6 carrying the cauterizing electrode is at that moment in the region 12 around the hole to be occluded. In the present description, reference has been made to a flow sensor consisting of a temperature sensor that "reads" the temperature difference between a stagnating blood and a flowing blood. Again according to the invention, it is anyway possible to use different solutions to discriminate the conditions of flow in proximity of the perforation to be occluded. Similarly, the electrodes for the local heating of the blood, and the electrodes for the cauterization of the artery wall, may be replaced by a variety of means, and the same thermal sensor - herein indicated as a thermocouple - could be of a different nature. In particular, the chemical-phisical characteristics of the active electrode are intended to ease the hemostasis process during the delivery of RF energy.

A first characteristic is the choice of a rounded or ellipsoid frusto-conical shape for the distal end of the catheter, in order not to causes traumas to the inner wall of the vessel upon inserting the catheter.

Moreover, in the construction of the active electrodes, it has been found important using materials the composition and working of which are able to minimizing both mechanical and chemical-phisical adhesion of the biological material to the electrode. Among these, electrodes of mechanically polished stainless steel, or of more inert materials, for example ^' noble metals such as platinum and others, may be used. Finally, provision may be made for depositing antifriction substances on the electrode surface which improve the adhesion repellency of the biological material. The invention thus conceived may also be subjected to several modifications and variants, all of them falling within the inventive scope; moreover, all the parts can be replaced by technically equivalent elements.

Claims

1. Apparatus for hemostasis of the vascular hematic effusion, comprising a probe or catheter (6) sliding within a cannula (2) for the insertion through a portion of the dermis (3), and provided with means (7, 8) able to make a hemostasis of a hole (5) of the wall of a vessel (4), and with at least a flow sensor (7) disposed in proximity of a distal end of the probe (6), wherein said flow sensor is a thermocouple (7) able to discriminate between the temperature in a region (11) of blood flowing within the vessel and the temperature of the blood stagnating in a region (12) around the hole of the vessel (4)'s wall, said thermocouple (7) making up at the same time the active electrode for the cauterization of the hole (5) by the emission of radio frequency.

2. Apparatus according to claim 1, wherein said means for the hemostasis comprise a second reference electrode (8).

3. Apparatus according to any of claims 1-2, wherein said probe (6) is provided with means (7, 8) disposed at the distal end of the probe (6) and able to induce a controlled local heating.

4. Apparatus according to any of claims 1-3, wherein said heating means consist of said radio frequency-emitting electrodes (7, 8). 5. Apparatus according to any of claims 1-4, wherein said thermocouple (7) is of copper-constantan type, β. Apparatus according to any of claims 1-5, wherein said reference electrode (8) of RF energy-delivery is made up of a surgery plate located on the back of the patient. 7. Apparatus according to claim 6, wherein said probe (6) consists of the single electrode (7) acting as a temperature and RF energy-delivery sensor.

8. Apparatus according to any of the preceding claims, wherein said active electrode (7) has a lead-in shape for the introduction and extraction into/out of the vessel (4).

9. Apparatus according to any of the preceding claims, wherein said active electrode (7) is made from a material which is adhesion-repellent to the biological material of the vessel (4) . 10. Instrumentation for operations of vascular flow hemostasis, comprising an apparatus according to any of claims 1-4, further comprising an external control unit that can be connected at least with said thermocouple (7) for continually measuring and controlling the sensed flow. 11. Instrumentation according to claim 10, wherein said control unit comprises means for controlling the blood's local heating induced by said electrodes (7, 8) .

12. Instrumentation according to claim 11, wherein said means for controlling the blood' s local heating are made up of an RF generator connected to said electrodes (7, 8) for the emission of radio frequency energy as a function of the sensed temperature and of a desired temperature.

13. Instrumentation according to any of claims 10-12, comprising means for controlling the Rf emission from said electrodes for the cauterization of a vascular perforation (5) .

14. Instrumentation according to claim 13, wherein said control means are automatic, as they are activated by the variation of temperature sensed by the temperature sensor (7) when exiting from the arterial bed.

15. Method for the hemostasis of hematic effusion of a vascular perforation (5), comprising the following steps:

- inserting, through a perforation (5) of the wall of a vessel (4), the distal end of a catheter (6) provided with hemostasis means (7, 8) for closing the perforation (5), and with at least a flow sensor (7) disposed at a known distance from the hemostasis means (7, 8), for moving said sensor (7) up to a region of hematic flow (11) of vessel (4); - detecting the presence of hematic flow (11) in said region by said sensor (7);

- progressivelly withdrawing the catheter (6) to move the sensor (7) out of the region of hematic flow (11) while performing repeated measurements of flow in order to detect the position of the sensor (7) corresponding to a region (12) surrounding the perforation (5) in the absence of hematic flow;

- detecting a first position of the hemostasis means (7, 8) corresponding to a position of the catheter (6) in which the absence of flow has been detected;

- positioning the catheter (6) on the basis of the detected first position to dispose said hemostasis means (7, 8) at an operating position close to the perforation (5) ; .

- activating said hemostasis means (7, 8) in said operating position to close said perforation (5) .

16. Method according to claim 15, wherein said flow sensor (7) is a temperature sensor responsive to the thermal flush induced by the hematic flow.

17. Method according to claim 16, further comprising the steps of:

- detecting the temperature in said region (11) of hematic flow (11) by said sensor (7);

- progressivelly withdrawing the catheter (6) to move the sensor (7) ^■ out of the region of hematic flow (11) while performing repeated measurements of temperature in order to detect the position of the sensor (7) corresponding to a region (12) around the perforation (5) where there is absence of hematic flow; detecting repeatedly a difference between successive measures of temperature and comparing the detected differences with a preset value (ΔT) ;

- identifying the first position of the hemostasis means (7, 8) as the position at which a difference has been detected between successive readings of temeperature higher than or equal to the (ΔT) value.

18. Method according to claim 17, wherein said temperature sensor (7) is a thermocouple.

19. Method according to claim 18, wherein said sensor (7) makes up, at the same time, an active electrode for the cauterization of the perforation (5) through the emission of radio frequency.

20. Method according to claim 19, wherein said electrode (7) is operated to emit radio-frequency energy to induce a controlled local heating within the vessel (4) .