Protective device and method against embolization in carotid angioplasty

IS 2 340 559 T3

DESCRIPTION

Protective device for embolization in carotid angioplasty.

Technical field

The present invention relates to a protective device against embolization in vascular angioplasty, preferably of the carotid one. The device comprises a guide catheter that can be placed in a vascular conduit, a tube, that can be inserted through the catheter, and an occluder at the distal end of the tube. The occluder is expandable against the vascular conduit to occlude antegrade blood flow. The occluder has a port for drainage of antegrade blood flow, which allows the retrograde blood flow with any plunger to drain through the internal passageway of the occluder and through the tube to be discharged outside the patient's body. The present invention allows the temporary reversal of antegrade blood flow to prevent emboli from reaching the brain, and allows the emboli to drain out of the patient's body.

An anti-embolization procedure, which is not part of the present invention, may comprise the use of the device in conjunction with vacuum suction to allow reversal of blood flow to prevent emboli from reaching the brain and to allow emboli to pass. drained from the body, cleansed, and blood re-infused into the patient's bloodstream.

Background of the invention

Although conventional open surgery has traditionally been used to treat vascular diseases, such as carotid artery stenosis, endovascular treatments are now gaining acceptance. Endovascular treatments are carried out in the lumen of the vascular duct and have the advantage of being less aggressive than open surgery, posing a lower risk to the patient, because it can be carried out with limited local anesthesia.

When there is stenosis of an artery, such as the common carotid artery, the internal carotid artery, or the external carotid artery, the vascular wall of the artery is affected by a pathological narrowing that prevents the blood stream from flowing normally. A common treatment is endovascular angioplasty, in which an angioplasty balloon ( 6) is inserted into the lumen of the vessel and the angioplasty balloon (6) is expanded to expand the area with the stenosis. If necessary, a stent (8) is placed to cover the affected area.

The problem with this treatment is that emboli can form during the procedure that can quickly reach the brain and cause injury and death. Emboli are especially prone to form when instruments pass into or through the stenosis and / or the angioplasty balloon expands or while the stent is being placed and expanded.

With reference to the prior art, US 5,011,488 (Ginsburg) discloses a vascular catheter system in which a flexible tube member (18) with a end portion (16) extending radially. Flexible member (18) may extend from within tube (12) to a position beyond a clot or thrombus located within a blood vessel (VS), with flexible end portion (16) extending radially to conform to the inner wall of the vessel (VS). Subsequently, the radially extended flexible member (16) is withdrawn, dislodging and absorbing the clot material into the outer tube (12). Suction or aspiration is applied via a junction box (44) to aid in the removal of clot material from the vein and through the catheter. An inner tube (14) located within the outer tube (12) also comprises an extensible portion (30), generally conical, which is used to collect the clot material while the flexible member (18) removes the material.

Procedures for monitoring blood flow and thus indicating the existence of emboli are known in the art. One such system, called a transcranial Doppler monitoring system, measures the direction and speed of blood flow in an artery in the brain, such as the middle cerebral artery. Surgical and endovascular procedures on the carotid artery can be performed while the transcranial Doppler system measures the speed of blood flow in an artery.

Under normal conditions, the bloodstream has an antegrade flow, that is, it goes forward, so that in the carotid artery it goes from the common carotid artery to the external and internal branches. In conventional surgery, the artery is first occluded and blood flow is cut off distal to the occlusion, before treating the stenosis. However, this surgery has some risk, since the occlusion of the blood flow can cause cerebral ischemia. Therefore, in conventional surgery, after the vessel has been occluded, some surgeons use a shunt, which is placed to allow temporary conduction of blood flow to areas distal to the occlusion. Dissection of the artery and bypass instrumentation could lead to the passage of emboli to the brain and consequent injury to the patient, or even death. During carotid angioplasty and stenting, particles are often produced by the procedure itself. Passing a guidewire through the stenosis, vigorously dilating the stenosis with a balloon, and deploying and expanding stents can precipitate embolization of the brain.

IS 2 340 559 T3

Therefore, there is a need in the art for a device that allows removal of emboli during endovascular angioplasty.

The present invention recognizes that, typically, blood flow does not stop completely distal to surgical occlusion of a carotid vessel, because there are anastomoses or intercommunications between arterial vessels through the connection of crossed branches, allowing the blood flows distal to the occlusion. For example, there is such collateral flow between the internal carotid artery and the branches of the external carotid artery. In addition, the connections within the Circle of Willis (900) also allow collateral blood flow. Previously, retrograde perfusion on the venous side has been used to provide blood flow to the brain. Reversal of blood flow in the heart has also been used, such as when veins are used to bypass the arteries of the heart, or when the left ventricle of the heart is connected to a vein to treat end-stage heart disease.

The present invention allows blood flow to be reversed under control, thus emptying the emboli generated by angioplasty out of the patient's body, and utilizes naturally occurring anastomoses to allow blood flow to areas distal to the occlusion. during the relatively short times when blood flow is reversed during the operative procedure.

The present invention recognizes that a funnel-shaped balloon or occluder will direct all blood flow and all emboli within the tube within the catheter to be discharged outside the patient's body, where blood can be flushed from the emboli. and then be returned to the patient intravenously.

Summary of the invention

The invention comprises a tube positioned within a guide catheter and movable in an axial direction. The tube is provided with a distal end, a proximal end, a tubular body, and an internal passageway. At the distal end of the tube is an occluder, which is expandable against the vascular conduit to occlude antegrade blood flow. The occluder has a port for the drainage of retrograde blood flow from its distal end, through its internal passageway, through the tube, to exit the patient through an inlet at the proximal end of the tube. Preferably, the occluder comprises a structure which is funnel-shaped with non-collapsible edges, or which may be in the form of a funnel-shaped balloon to direct all flow and particles within the tube. At its proximal end, the tube may be provided with a plurality of branched connections. One of the branches is connected to an outlet that is equipped with a hemostatic valve and a pump, which can be used to apply vacuum pressure, to establish a retrograde blood flow, and to remove the emboli by suction. Another of the branches connects with an entrance and provides an access route to its internal passageway. The tube can be provided with a plurality of branches, each of which has an inlet. The branches are located on the tube in such a way that, when the tube is inserted into the catheter, the branches remain outside the catheter.

When used, the distal end of the tube, with the attached occluder, is positioned at the proximal end of the catheter, extends through the catheter, and then exits the distal end of the catheter. The occluder is then expanded against the vascular walls. When a balloon is used as an occluder, expansion can be accomplished by means known in the art, such as injecting a saline solution or radiopaque material into the balloon. When a funnel other than a balloon is used as the occluder, expansion can be achieved by means known in the art, such as passage of the occluder beyond the distal end of the catheter, where, in the absence of tensioning pressure from the catheter walls, the funnel other than a balloon can expand spontaneously. Alternatively, when a funnel other than a balloon is used as the occluder, the occluder can be placed within a sheath and expansion can be achieved by retracting the sheath in a proximal direction, allowing the occluder to expand. Once expansion is achieved, the occluder is shaped like a calyx or funnel, and occludes the antegrade flow of the bloodstream in which it is situated, and allows the retrograde flow of blood through its drainage port. and then through the tube exits the patient's body.

When the hemostatic valve is opened and vacuum suction is applied, retrograde blood flow occurs that carries the emboli through the mouth of the occluder, and then through the tube, to the exterior of the body, to a manifold, like a bottle, or to a cleaning system. The branch of the tube connected to the outlet may be provided with means, known in the art, to clean the blood from emboli. The emboli blood cleaning means may include a filter known in the art, such as the Baxter filter or the Therumo filter. The hemostatic valve may be connected to a vacuum system known in the art, which comprises a pump to create a negative pressure in the tube connected to the hemostatic valve. Once the blood has been cleared of emboli, the blood can be reintroduced into the patient intravenously. In this way, emboli are prevented from reaching the brain and are removed from the blood collected outside the body before the blood is injected back into the patient.

An anti-embolization procedure, which is not part of the invention, may comprise the use of the device in conjunction with vacuum suction, preferably in four phases of carotid angioplasty, 1) during the advancement of the guidewire through the stenosis , 2) during balloon dilation, 3) during stent deployment, 4) during stent expansion, to allow reversal of blood flow to prevent emboli from reaching the brain and to allow blood to drain out of the body, clear of emboli, and reinfuse into the patient's bloodstream.

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Brief description of the drawings

Figure 1a is a longitudinal perspective view of the protective device with the occluder in its contracted inoperative position.

Figure 1b is a longitudinal perspective view of the protective device showing the occluder beginning to emerge from the distal end of the catheter and expanding against the walls of the blood vessel (not shown).

Figure 2 is a longitudinal view of the carotid artery, in which an angioplasty balloon expands the stenosis and causes the undesirable formation of emboli, as in the prior art, which can then advance distally to the brain, carried by antegrade flow from the bloodstream.

Figure 3 is a longitudinal view of the carotid artery, in which the placement of an expander or a stent, as in the prior art, also generates dangerous emboli, carried distally by the blood to the brain.

Figure 4 is a partial longitudinal view of the protective device of one embodiment of the present invention (not showing the tube) being inserted into the carotid artery, in which the occluder begins to exit the guide catheter and expand.

Figure 5 is a partial longitudinal view of the protective device of one embodiment of the present invention (the tube not shown) in the carotid artery in which expansion of the occluder against the vascular walls has been completed. It can be seen how the outer edges of the occluder occlude the antegrade flow of blood and prevent clumping or stagnation of blood between the occluder and the walls of the blood vessel, while the blood begins to flow retrograde through the mouth of occluder and tube drainage.

Figure 6 is a longitudinal view of one embodiment of the protective device in the carotid artery with the distal end of the occluder expanded in the shape of a funnel or calyx and in which the blood flow is reversed (as shown by the arrows) and is then retrograde when the hemostatic valve is opened.

Figure 7 is a longitudinal view of one embodiment of the protective device in the carotid artery and an angioplasty balloon catheter in the internal carotid artery. Shows retrograde blood flow leading emboli to the occluder drainage port.

Figure 8 is a longitudinal view of one embodiment of a portion of the protective device (catheter not shown) showing an occluder and the side inlet of the tube for blood drainage.

Figure 9 is a schematic view of the prior art showing a spherical balloon and arrows indicating where emboli can get trapped in the balloon.

Figure 10A is a schematic view of the collateral circulation commonly found after occlusion of the internal carotid artery.

Figure 10B is a schematic view of reduced collateral circulation after occlusion of the internal carotid artery, in which there is an abnormal insufficiency of segments of the cerebral arterial circle of Willis.

Figure 11 is a schematic picture illustrating the steps of one embodiment of a procedure, not part of the invention, against embolization in carotid angioplasty.

Figure 12 is a partial longitudinal perspective view of one embodiment of the protective device of the present invention (catheter not shown) showing an embodiment in which the occluder is within a retractable sheath.

Figure 13 is a partial longitudinal perspective view of one embodiment of the protective device of the present invention (catheter not shown) showing an embodiment in which the occluder is expanded after the sheath has been retracted.

Figure 14 is a partial perspective view of a balloon occluder in its expanded position (catheter not shown).

Figure 15A is an example of a partial longitudinal section of the protective device (catheter not shown) showing an embodiment of an occluder other than a balloon in its contracted configuration.

Figure 15B is a horizontal section of the protective device (catheter not shown), as shown in Figure 15A, with the non-balloon occluder in its contracted configuration.

Figure 16A is an example of a partial longitudinal section of the protective device (catheter not shown) showing an embodiment of an occluder other than a balloon in its expanded configuration.

IS 2 340 559 T3

Figure 16B is a horizontal section of the protective device (catheter not shown), as shown in Figure 16A, with the non-balloon occluder in its expanded configuration.

Description of the preferred embodiments

The protective device against embolization (b) in carotid angioplasty illustrated in Fig. 1b comprises a tube (12), inserted through a guide catheter (9), and an occluder (14) at the distal end ( 13) from the tube (12). The occluder can either be integral with the tube, or be attached to it. The tube (12) moves in an axial direction, that is, longitudinally with respect to the guide catheter (9). The tube (12) comprises a cylinder having a distal end (13), a proximal end (120) and a body, within which there is a cavity that forms an internal passage (90).

The occluder (14) is forced to be inoperative within the guide catheter (9) in a configuration in which the occluder has a reduced diameter distal edge (802). The occluder (14) then passes out the distal end of the guide catheter (9) and expands against the vascular conduit to occlude antegrade blood flow (4).

The occluder (14) has a mouth (15) for the drainage of emboli (3) into the internal passage of the occluder. The occluder has a first reduced size configuration and a second expanded size configuration, the occluder being expandable from its first configuration to its second configuration. As with funnels in general, the occluder has a proximal edge (801) that forms a first proximal opening (800) within the occluder at its proximal end, which is narrower than the mouth (15) of the distal end, when the occluder is in its expanded configuration. In its expanded configuration, the occluder has a funnel-shaped body, the body comprising a funnel-shaped wall that forms an internal passageway having a distal mouth and a first proximal opening (800). The first opening (800) forms a seal with the tube opening (12) at the distal end (13) of the tube. Preferably, the first opening (800) of the occluder (14) is near the center of the body (26) of the occluder. Blood and emboli drain through the mouth (15) of the occluder (14), the first opening (800) of the occluder and pass through the distal end (13) of the tube (12) through its internal passage ( 90) to the proximal end (120) of the tube (12) to exit the patient's body through the outlet (16). The occluder (14) is expandable and, as is known in the art, is made of an expandable and impermeable material. Materials with similar properties to known expanders can be used, such as the CORVTTA ™ stent, although this material should not be combined with an impermeable material, since the occluder (14), as described herein, must be capable of to function to occlude the passage of blood. In one embodiment, the occluder is made of a shape memory metal (eg, NITINOL ™), which will shape between its austenitic and martensitic states upon application and removal of temperature (eg, body heat) or tension. Alternatively, other elastic materials can be used. As a further example, an occluder balloon can be made of metal braided polyurethane, or other biocompatible material.

Preferably, the occluder (14) has a funnel-shaped body (26). In one embodiment, the occluder can be as described above, but constructed from an inflatable balloon (500). Inflatable angioplasty balloons are known in the art. However, in accordance with the present invention, the occluder balloon is funnel-shaped, as shown in Fig. 14. In an alternative embodiment, the occluder may have a shape other than a balloon, having a funnel shape with a central drainage mouth (15) and a non-collapsible distal edge (24) that meets the walls (2) of the conduit. vascular to avoid and occlude the antegrade passage of blood and the direct retrograde flow of blood and emboli through its drainage mouth (15), as shown in Fig. 1b.

Furthermore, in the operative position of the occluder, in which it projects outside the guide catheter, it undergoes a radial expansion by means of which it reaches a diameter greater than that of the guide catheter (9). Thus, in one embodiment, the guide catheter (9) has a diameter of approximately 9 French or 3.0303 mm, the tube has a diameter of approximately 8 French or 2.72727 mm, and the expanded occluder (14) is capable of reaching a diameter of 12 millimeters. As shown in Fig. 5, in its expanded position against the walls (2) of the vascular conduit, the occluder (14) acquires a shape similar to that of a funnel or a calyx.

In an embodiment where the occluder (14) is a funnel other than a balloon, the occluder (14) can be positioned, in its contracted position, within a sheath (700). The sheath (700) is a cylinder that has a cavity and is known in the art. As is known in the art, the sheath can be composed of plastic, plastic combined with metal, or any other suitable material (preferably biocompatible). Preferably, the sheath is dimensioned so that its width is slightly greater than the width of the occluder in its contracted position, so that the pressure of the inner walls of the sheath on the occluder maintains the occluder (14) in its contracted position. In the preferred embodiment, the sheath is dimensioned such that its length is long enough that, when the occluder is inserted into the sheath and the occluder is properly positioned on the patient at the level of contemplated use, the distal end of the the sheath extends beyond the distal end of the occluder and the proximal end of the sheath extends outside the patient's body. In an alternative embodiment, the sheath partially covers the occluder, with the sheath sufficiently covering the occluder so that the occluder is forced to remain in its contracted, reduced diameter position. Thus, the retractable sheath can be retracted by the operator pulling the portion of the sheath outside the body to pull the sheath back, exposing the occluder. In another embodiment, the sheath is attached to an extension means, such as thread, plastic filament, rope, etc. (706), by adhesive, glue, fusion, or other conventional means known in the art. The operator can manually pull the extension device to retract the occluder sheath to allow the occluder to expand.

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In such an embodiment, the sheath may be dimensioned such that its length, in combination with the length of the extension device, together form a length that the extension means extends out of the patient's body and the occluder in position. contracted within the sheath is positioned on the patient at the level of intended use.

The proximal end (120) of the tube (12) may be provided with a plurality of branch connections (16) (17). One of the branches is an outlet (16) that is provided with a hemostatic valve (160) and a vacuum pump mechanism (240). The vacuum pump mechanism is known in the art and, by way of example, vacuum pump systems used in blood donations can be used here. One or more of the branches is an inlet (17) that provides an access path to the internal passage (90) of the tube (12). The branches are located in the tube (12) in such a way that, when the tube (12) is inserted into the guide catheter (9), the branches remain outside the guide catheter (9). The tube can be made of a material known in the art.

Guide catheter (9) is known in the art. The guide catheter (9) comprises a cylinder provided with a proximal end (10) and a distal end (11) and having a flexible body within which there is a cavity. For example, the elements of the intervention, such as, for example, a guide wire (7), an angioplasty balloon (6) (6) and a stent (8) can pass through the guide catheter (9) and can be passed through the tube (12) into the guide catheter (9).

The protective device against embolization (b) is used in carotid angioplasty or any other suitable procedure to form a system that allows drainage of the emboli (3) of a patient undergoing carotid angioplasty. Angioplasty is a surgical procedure to reduce or eliminate the stenosis (22) of the wall (2) of a vascular conduit.

The protective device against embolization (b) works as follows. A guide catheter (9) is introduced into the lumen (18) of an arterial blood vessel that has a bloodstream that normally has antegrade flow (4). Typically, in carotid angioplasty, the guiding catheter is inserted through the femoral artery of the patient. Being connected to the tube (12), the occluder (14) is inserted into the proximal end (10) of the guide catheter (9) and, at that moment, the occluder (14) is inoperative inside the guide catheter (9 ), that is, it is required to have a small configuration in the guide catheter. By exerting pressure on the tube (12), the occluder (14) passes directly through the cavity of the guide catheter (9) and exits the guide catheter (9) through its distal end (11). The occluder (14) is then expanded or caused to expand against the walls (2) of the vascular conduit.

If a balloon occluder is deployed, the balloon can be expanded by introducing a saline solution, radiopaque material, or in other ways known in the art.

An occluder other than a balloon, which is funnel-shaped, can expand naturally as it passes the distal end of the guide catheter and is therefore released from the tensioning pressure of the guide catheter walls. Likewise, a shape memory metal occluder can be expanded by applying temperature to the occluder (i.e., heating it, due to exposure to body heat) and / or by removal of stress (i.e. passage of the occluder beyond the restrictive tubular walls). Thus, the non-balloon occluder moves from its restricted position within the guide catheter (9) to an external projection position beyond the distal end (11) of the guide catheter (9).

In an alternative embodiment, an occluder (14) other than a balloon, in its contracted position, being connected to tube (12), may be placed within a sheath (700) before the occluder (14) and tube ( 12) are introduced into the patient through the catheter (9). In this embodiment, the occluder (14) other than a balloon within the sheath (700) and tube (12) can then be inserted into the proximal end (10) of the guide catheter (9) and the occluder can be passed distally. through the cavity of the guide catheter and out of the guide catheter at its distal end, and yet the sheath (700) will continue to force the occluder (14) to remain in the contracted position of the occluder. The sheath can be of such a length that it extends outside the patient's body, or the sheath can be attached to an extension device that extends outside the patient's body. Respectively, either the end of the sheath that extends out of the patient's body or the end of the extension device that extends out of the patient's body can be pulled, thus retracting the sheath from around the occluder and allowing the occluder to expand against the walls (2) of the vascular conduit.

Once expansion is complete (preferably to the shape of a funnel or calyx), the non-collapsible distal edge of the occluder other than a balloon or the inflated balloon will press against the vessel wall, blocking the antegrade flow of the bloodstream. . The funnel shape further eliminates the creation of pockets in which emboli can accumulate, which is a problem in the prior art.

Following expansion of the occluder, endovascular procedures, such as carotid angioplasty, can be performed. For example, a guidewire, angioplasty balloon, stent, or any other suitable device or instrument may be passed through the cavity within the tube and the mouth of the occluder to reach the area of ​​the vascular walls affected by the stenosis for a appropriate treatment.

After expansion of the occluder and at appropriate times when the operator wishes to drain the emboli, the surgeon can open the hemostatic valve (160) and a retrograde flow (5) occurs, carrying the emboli (3) generated by the operation through the mouth of the occluder (15), through the internal passage (90) of the tube (12) and

ES 2 340 559 T3 through the outlet (16) to exit the patient's body. This retrograde flow is directly opposite to the normal direction of blood flow and directs blood away from the brain. Once the blood and emboli leave the patient's body, the blood can be cleared of emboli (e.g., as is known in the art, using a blood filtering device) and the blood can be reintroduced into the patient by intravenously. Thus, the protective device against embolization prevents the emboli (3) from reaching the brain.

The occluder can be returned to its contracted position when the expanded configuration of the occluder is not needed to drain blood or emboli. In one embodiment of an occluder other than a balloon, the tube attached to the occluder can be moved proximally until the occluder returns to its contracted configuration within the catheter. In another embodiment of an embolization protective device comprising an occluder other than a balloon, connected to a tube, the sheath (700) may be pushed distally to return the occluder to its contracted configuration within the sheath. A balloon occluder can be returned to its contracted position by removal of saline, radiopaque material, or in other ways known in the art.

In particular, as described below, a new anti-embolization procedure in carotid angioplasty, which is not part of the present invention, can make use of the protective device.

The protective device against embolization (b) can be used in angioplasty, and particularly in carotid angioplasty, according to the following procedural procedure, which is schematically illustrated in Fig. 11 and does not form part of the invention . At the beginning of the procedure, preferably, a Doppler monitor (200) or a transducer is applied according to conventional means to monitor blood flow distal to the occlusion. For example, in carotid angioplasty, a transcranial Doppler monitor is placed over the temporal bone or a transducer is applied to the neck according to conventional procedures to monitor blood flow in the patient from the common carotid artery (180), the artery external carotid (100), internal carotid artery (101) or middle cerebral artery. The transcranial Doppler monitor will allow the physician to monitor the direction of blood flow in subsequent stages.

Once the Doppler monitor (200) is set up, a guiding catheter (9) is inserted into the patient and passed to the appropriate artery, which, in the case of carotid angioplasty, is preferably the common carotid artery (180). Preferably, to minimize the formation of potentially dangerous emboli, the catheter does not pass into or through the stenosis. Next, the occluder (14), attached to the tube (12), is passed through the guide catheter and positioned proximal to the stenosis, also, preferably, without passing into or through the stenosis. The occluder (14) is then expanded until the edge of the distal edges of the occluder is flush with the walls of the blood vessel. Most patients will tolerate this temporary common carotid occlusion, some will not; in this second group of patients, this procedure should be abandoned. The operator then applies vacuum suction to drain the emboli and determines when there is reversal of blood flow distal to the occlusion (for example, using the transcranial Doppler monitor, or some other suitable device or procedure, such as a transducer, etc.) . When flow reversal is achieved, the surgeon can pass an instrument such as a guide wire and balloon catheter for angioplasty through the tube (12) and pass it through the mouth (15) of the occluder (14) plus beyond the stenosis. Since the flow reversal has been established prior to the passage of any instrument beyond the stenosis that could dislodge emboli, the emboli will flow in a retrograde direction, into the mouth of the occluder, and will flow through the protective device to exit the occluder. patient's body. The vacuum pressure is released after the instrument has passed the stenosis and the emboli have drained. In this way, the risk of the prior art of creating emboli targeting the brain is reduced or eliminated.

More particularly, in carotid angioplasty, the procedure can be categorized into four phases and in each of the four phases a negative pressure can be applied at appropriate times by using the embolization protective device (b) to drain emboli .

In a first phase, a Doppler monitor (200) is configured. Next, a guide catheter (9) is inserted into the patient and passed into the common carotid artery (180) using a guide wire system (wire system), taking care not to cross the stenosis with the end of the wire guide; Typically, the end of the guidewire should be positioned in the external carotid artery (without insertion into or through the stenosis). The tube (12), with the occluder (14) attached, is then passed through the guide catheter and the occluder is positioned proximal to the stenosis. The occluder (14) is then expanded. In phase 1, before passing an instrument, such as a guide wire (7) through the stenosis, vacuum suction is applied by means of a vacuum pump mechanism (240) attached to the outlet (16). Such vacuum suction is applied until brain flow distal to the stenosis is reversed (5), and continues until the maneuver of passing the instrument, like a guide wire, through the stenosis is completed. Typically in this phase 1 vacuum suction is applied for about 10 seconds. Vacuum suction will drain any plungers that may have been dislodged by the instruments passing through the stenosis. Use of the Doppler monitor (or other suitable monitoring device, for example a transducer) will indicate when reverse flow is achieved in the brain distal to the stenosis.

In the second phase, an angioplasty catheter with an angioplasty balloon with a guide catheter (9) can then be introduced into the tube (12) through the inlet (17). In phase 2, in the pre-dilation state, the angioplasty catheter with the angioplasty balloon is placed at the level of the stenosis. In phase 2, at the time the angioplasty catheter with the angioplasty balloon is placed near the level of the stenosis and before dilation of the

ES 2 340 559 T3 angioplasty balloon, the vacuum is applied again until the blood flow is reversed distal to the stenosis by means of the pump mechanism attached to the outlet (16) and it is continued until the balloon angioplasty is properly placed at the level of the stenosis, the angioplasty balloon is inflated by introducing a saline solution, radiopaque material or other ways practiced in the technique, and the balloon is removed proximal to the stricture. Typically, in this phase, vacuum suction is applied for about 15-20 seconds. Inflation of the angioplasty balloon disintegrates the stricture and allows emboli to be released into the bloodstream. The vacuum suction will then drain any plungers that may have dislodged. Use of the Doppler monitor or a suitable device will indicate when reverse flow is achieved in the brain distal to the stenosis. After the angioplasty balloon is deflated, the angioplasty balloon is removed from the patient's body.

In phase 3, a stent is introduced through an entrance (17) in the tube (12) within the guide catheter (9). As the stent approaches the stricture, vacuum suction is applied until flow is reversed distal to the stricture and the stent is positioned in the stricture. Typically, in this phase, vacuum pressure is applied for about 30 seconds. The vacuum will drain any plungers that may have dislodged. Use of the Doppler monitor or similar will indicate when reverse flow is achieved in the brain distal to the stenosis.

In phase 4, a stent balloon, also called an inflation balloon (ie, a balloon used to inflate a stent), is inserted into the inlet (17) in the tube (12) within the guide catheter (9). As the stent balloon approaches the stricture, vacuum suction is applied until flow is reversed distal to the stricture, and vacuum pressure continues to be applied until the balloon is inflated to expand the stent into the stricture, the balloon is deflated and removed proximally to the stricture. Typically, in this phase, vacuum suction is applied for about 15-20 seconds. The vacuum will drain any plungers that may have dislodged. Use of the Doppler monitor or similar will indicate when reverse flow is achieved in the brain distal to the stenosis.

Preferably, reverse blood flow is established only intermittently during the procedure, for short periods. Although it is possible to maintain a continuous reverse flow throughout the procedure, such sustained reverse flow is not preferred due to the inconvenience of depriving the brain of oxygen for prolonged periods. In the preferred embodiment, during each phase of a procedure that could result in emboli detachment, reverse flow is initiated only as long as necessary to ensure that all potential emboli are drained and completely removed from the bloodstream. Accordingly, the vacuum suction periods provided are representative of periods believed to be useful in practice, but slightly shorter or longer periods may be necessary or useful in a particular procedure or type of procedure or for a specific procedure. particular patient.

Typically, use of the present method, which is not part of the invention, results in the drainage of approximately 300 cc of blood, but the amount of blood drained can vary. The blood that is drained can be passed through a filter system (220) and can be cleaned out of the patient's body by means well known in the art. After the blood has been cleaned, the blood can be put back into the patient intravenously.

Thus, as described above, the non-inventive procedure against embolization reverses blood flow in the brain distal to the four-stage stenosis during the carotid angioplasty procedure. Alternatively, the procedure, not according to the invention, against embolization may comprise any one of the four phases or any combination of the four phases. The total period of reversal of blood flow in the brain distal to the stenosis is approximately one minute. In a typical patient, blood flow may reverse for up to approximately three minutes before any danger of ischemia is likely to occur. Fig. 10A illustrates a schematic drawing of the circulation, as typically occurs in the segments of the cerebral arterial Circle of Willis.

However, less than five percent of patients are likely to have abnormal cerebral arterial Circle of Willis segment failure. Anomalous insufficiency of segments of the cerebral arterial Circle of Willis is known to reduce collateral flow and can result in ischemia when blood flow is reversed even for a relatively brief period of three minutes or less. Fig. 10B illustrates a schematic drawing of abnormal cerebral arterial Circle of Willis segment failure.

It is significant to recognize that suction or vacuum can also be applied without achieving the purpose of reversing flow in the internal carotid artery distal to the stenosis. The reversal of flow is related to the amount of blood drained per unit of time and to the suction time. Therefore, it is important to use the Doppler monitor (200) or the like to ensure that reversal of the blood has occurred when the surgeon is attempting to remove the emboli by applying suction.

This protective device (b) is applicable in angioplasties aimed at treating arterial stenosis (22) that affects walls (2) of vascular conduits. In particular, the protective device (b) is applicable in carotid angioplasties in which there is a stenosis (22) in the carotid artery. The carotid artery is made up of the common carotid artery (180) and its leads into the external carotid artery (100) and the internal carotid artery (101). Within the vascular conduit, the bloodstream normally has an antegrade flow (4), that is, from the common carotid artery (1) to the branches (100) and (101).

IS 2 340 559 T3

In alternative embodiments of the present invention, the apparatus may be used in other anatomy procedures and repairs where there is a risk of forming dangerous emboli.

Having described the present invention with respect to its preferred embodiments, it should be understood that the description should not be construed as a limitation, as additional variations or modifications may be obvious or suggest themselves by themselves to those skilled in the art. The present application is intended to cover such variations and modifications that fall within the scope of the appended claims.