WO2010076838A1

WO2010076838A1 - Catheter for the embolization with transcaval approach of a type i and type il endoleak subsequent to the treatment by means of the application of an endovascular stent graft of an aneurysm of the abdominal aorta

Info

Publication number: WO2010076838A1
Application number: PCT/IT2009/000586
Authority: WO
Inventors: Roberto Gandini
Original assignee: Roberto Gandini
Priority date: 2008-12-30
Filing date: 2009-12-29
Publication date: 2010-07-08
Also published as: ITRM20080697A1

Abstract

The present invention refers to a catheter (14, 17) for the treatment by means of embolization with transcaval approach of type I and type Il endoleak subsequent to the application of endovascular stent graft (11 ) for the endovascular treatment of an abdominal aorta (10) aneurysm (12), comprising an exit hole (20, 21) for a cannula (15, 19) with a 40° to 90° variable angle with respect to the body of the catheter.

Description

CATHETER FOR THE EMBOLIZATION WITH TRANSCAVAL APPROACH OF A TYPE I AND TYPE Il ENDOLEAK SUBSEQUENT TO THE TREATMENT BY MEANS OF THE APPLICATION OF AN ENDOVASCULAR STENT GRAFT OF AN ANEURYSM OF THE ABDOMINAL AORTA

The present invention concerns a catheter for the embolization with transcaval approach of type I and type Il endoleak subsequent to the endovascular treatment of abdominal aorta aneurysm.

The invention refers to the field of endovascular treatment devices. The aneurysm of abdominal aorta (AAA) consists of a dilation of the arterial wall which tends to increase over the time and, due to intrinsic fragility thereof, is subjected to highest rupture risk, often leading to lethal consequences.

Given the inefficiency of the medical therapy in preventing the rupture risk, the traditional treatment of abdominal aorta aneurysms is of surgical type, and consists of resection of the involved aortic segment in combination with prosthetic replacement.

According to perspective for an increasing use of mini-invasive type techniques, already since the ^'90 beginning endovascular type techniques, initially limited for patients having particular co-morbidity or too elevated anesthesiologic risk, were provided.

During the last few years, the endovascular treatment of abdominal aorta aneurysms became an increasing use alternative, because it allows a rapid treatment not requiring a general anesthesia with remarkably reduced hospitalization and convalescence times.

This approach consists of the exclusion of the aneurysm by means of modular or not modular, self-expandable endovascular stent graft which is possibly bifurcated depending on the extension of iliac artery aneurysm. The endovascular stent graft is inserted directly inside of the abdominal aorta using put ting devices which are inserted by means of mono or bilateral femoral arteriotomy, said endovascular stent graft by expansion adheres to the walls of the aorta and the iliac arteries, excluding the aneurysm feeding.

The exact positioning of endovascular stent graft involves the exclusion of the aneurysmal sac from any direct blood feeding resulting in detention and pulsatility loss

In a first step, the aneurysmal sac is subjected to a complete thrombosis and successively, in absence of a blood feeding, resorption and re-adaptation phenomena occur.

The possible complications from the endovascular stent graft treatment can result from stent graft directly inherent factors, surgery operator error and patient anatomy relatable factors. More frequent complications are: migration, stent graft failure, separation of various segments in modular prostheses, i.e. so-called endoleak, so-called endotension, prosthesis occlusion.

Particularly, using the English term endoleak the feeding persistence between the systemic circulation and aneurysmal sac is defined.

Endoleaks are classified according to five types.

Type I endoleak is correlated to the failure of the prosthesis anchoring to the native artery proximally (Ia) or distally (Ib). This complication occurs where the neck diameter is under-estimated resulting in an inadequate choice of the prosthesis which does not adhere effectively to the vessel walls and consequently it is not suitable to exclude the aneurysmal bag. This type of endoleak makes the endovascular stent graft ineffective and it is to be corrected.

The treatment involves the positioning of a new prosthesis or possibly the use of proximal or distal cuffs or conversion to traditional surgery resulting in endovascular stent graft removal.

Type Il endoleak results from the feeding inversion of an artery from the aneurysmal bag (lumbar arteries and lower mesenteric artery) which supplies the aneurysm. This endoleak type is the most frequent and is detected only in later TC scanning. In high percentage of cases the aneurysmal bag remains stable, however only the presence of a type Il endoleak needs a continuous monitoring with semi-annual angio-TC controls resulting in the exposition of the patient to ionizing radiations and administration of organo-iodinated contrast media. In case of volumetric increase (>1 cm) an operation is necessary.

The endovascular approach generally is carried out by means of embolization of the supplying branch using coils or injection of thrombogenic substances, or by endoscopic application of clips.

Type III endoleak results from a prosthesis fault that can be related to a disjunction of the modular prosthesis members or graft breach. This occurrence is not very frequent and can be treated by means of positioning of another prosthesis excluding the bag supply.

Type IV endoleak results from the porosity of the prosthesis and generally occurs within 30 days from the positioning. Currently described cases of type IV endoleak when last generation prostheses are used, are very rare. The treatment is conservative.

Finally, type V endoleak results from an increase of the pressure inside of the bag resulting in enlargement thereof without evidence of blood feeding. This phenomenon is very debated not being clear the effective incidence thereof and how much it can be related to follow-up carried out with inadequate imaging techniques.

According to recently provided treatment procedure (G. Mansueto et al., "Treatment of Type Il Endoleaks After Endovascular Repair of Abdominal Aortic Aneurysms: Transcaval Approach", Cardiovasc Intervent Radiol (2005) 28:641-645) type Il endoleaks can be treated by means of a femoral venous approach and transcaval puncture under fluoroscopic control.

This radiological technique consists of the insertion of a guidewire in the femoral vein and advancement therein of a10 Fr inserting device inside of which successively a 40° angled metallic cannula at distal end thereof is inserted which is normally used in order to provide a porto- sistemic trans-jugular shunt. This is carried out under fluoroscopic guide allowing the system guideline with respect to the aneurysm to be verified by opportune projections.

At this time inside of metallic cannula a flexible cannula is advanced which, following the direction of the metallic cannula, pricks the caval and, by contiguity, aortic wall.

Once inside of the aortic lumen, the metallic needle is removed and using the cannula a guide is advanced distally through not thrombus affected zones of the aortic aneurysm and then on this guide the cannula suitable to carry out the embolization treatment is moved.

In case of type I endoleak, the guide is advanced into the zone wherein the endovascular stent graft does not adhere correctly. Through the guide is moved the cannula which will be localised at the level of the peri-prosthesis zone and used for the release of metallic coils. During the procedure the abdominal wall is continuously monitored.

At the end of the procedure, before the system removal, the possible presence of lesions in correspondence of the caval wall is monitored by means of cavography,

The above described operation methodology proves to be particularly effective (due to the excellent results and very low complication percentage) but actually is rarely applied. One of the reasons for this insufficient application results from the fact that a specific instrument suitable to carry out this type of operations is not available. Currently, in fact, the technique is carried out using a TIPS (Transjugular Intrahepatic Portosystemic Shunt) kit, which has been opportunely adapted for this purpose.

Moreover, the availability of said kit is unknown to the majority of the specialised medical workers involved in endovascular procedures (for example vascular surgeons and cardiologists), with the exclusion of the radiologists. The insufficient tendency of these professional workers to the use of adapted instruments and anyway outside of specific use designed to, is to be added to above.

In this context the solution according to the present invention is presented aiming to provide for a dedicated catheter suitable to allow in a standardized and reliable way the aneurysmal bag of the abdominal aorta to be pricked directly from the inferior vena cava and a wireguide to be advanced on the needle in the aneurysm, allowing therefore a second catheter to be advanced on the same wireguide for the embolization treatment. Thanks to the commercial availability of the described system exclusively dedicated to the embolization with transcaval approach, the possibility this technique for endovascular treatment to be used also by specialist workers who currently do not use the same, is suggested.

Therefore it is the object of the present invention to provide for a catheter allowing to overcome the limits resulting from the complexity of other currently used approaches in order to resolve the problem of the endoleak and obtain previously described technical results.

A further object of the invention is that said catheter can be produced at substantially reduced costs, both the production and operating costs.

Not last object of the invention is the production of a substantially simple, safe and reliably usable catheter.

It is therefore a specific object of the present invention a catheter for the treatment through embolization with transcaval approach of a type I and type Il endoleak after the application of an endovascular stent graft for endovascular treatment of an abdominal aorta aneurysm comprising an exit hole for a cannula having a 40° to 60° variable angle with respect to catheter body .

Preferably, according to the invention, said catheter further comprises a distal probe for endoluminal ecography using intravascular ultrasound technique (IVUS).

According to a preferred embodiment of the invention, the advancement of said cannula outside of the catheter is adjustable using the external handle of said catheter and said catheter further comprises a stabilizing balloon 180° angled with respect to the exit hole of said cannula.

Alternatively, again according to the invention, said catheter comprises a folded portion having a 40° to 90°, preferably 40° to 60° angle with respect to the catheter body at the distal end of said folded portion, said cannula being provided with an exit hole and a flexible stylet too. The present invention now will be described, by an illustrative, but not limitative way according to preferred embodiments thereof, with particular reference to enclosed drawings, wherein:

- figure 1 shows a schematic view of transcaval embolization operation area with a catheter according to the present invention, - figure 2 shows a schematic view of the end portion of a first catheter according to the present invention, and

- figure 3 shows a schematic view of the end portion of a second catheter according to the present invention.

With reference preliminarily to figure 1 , the abdominal aorta 10 is shown, wherein an endovascular stent graft 11 is implanted and which presents an aneurysmal bag 12 and the flanking vena cava 13, inside of which the terminal end of a catheter 14 according to the present invention is shown.

Particularly, with reference to figure 2, the catheter 14 can have a length variable from 60 to 100 cm with diameter from 9 to 12 Fr (from

3 to 4 mm) and an exit hole 20 of a 16-18 gauge cannula 15 that allows the passage of a 0,035 inch (0,889 mm) guide. This cannula 15 must have a variable angle (from 40° to 60° and up to 90°) and an advancement outside of catheter 14 adjustable using the external handle.

With reference to not negligible diameter of the inferior vena cava, the presence of a stabilizing balloon positioned at 180° with respect to the cannula 15 exit hole 20, which, by blowing up, contacts the vena cava and pushes the catheter 14, and particularly the cannula 15 exit hole 20 up to touch the caval wall in correspondence of aneurysmal bag 12. Moreover, the catheter 14 can be used in combination with a distal probe 16 for intravascular endoluminal echography by ultrasound technology (IVUS), in order to facilitate the detection of the catheter 14 position inside of the vena cava 13 and particularly the position of the cannula 15 exit hole 20.

With reference to figure 3, an alternative solution is provided consisting of a guide catheter 17 with a rigid (metallic) distal IVUS probe 18 having a portion 22 folded with respect to the catheter body 23 with a 40°-60° (up to 90°) angle α, at the distal end of this portion being present an exit hole of a 5 Fr (1 ,67 mm) cannula 19 provided with a flexible stylet allowing the aneurysmal bag 12 to be pricked following the direction of refolded portion 22, angled for an angle α with respect to the body 23 of guide catheter17. Finally guide catheter 17 comprises a distal portion 24, parallel to the body 23 of catheter 17, whereon said probe IVUS 18 is localised. The length of folded portion 22 is such that, considering the angle α, the body 23 and the distal portion 24 of catheter 17 are based on the opposite sides of the vena cava 13, the exit hole 21 of cannula 19 being in contact with the caval wall.

After the pricking of the caval wall and aortic aneurysm, the stylet can be removed and, by advancing a 0,035 inch (0,889 mm) guide, the cannula can be used to perform the embolization.

According to this second hypothesis the rigid catheter, leaning on the walls of the inferior vena cava, offers greater stability during the pricking and embolization and approaches more the needle tip to the caval wall and therefore to the aneurysm, thus eliminating the need of a stabilizing balloon resulting in the fact that the system gauge is not to be increased in order to allow the passage of stabilizing balloon feeding ducts.

The present invention has been described by an illustrative but not limitative way, according to preferred embodiments thereof, but it is to be understood that variations and/or modifications can be made by those skilled in the art without departing from the scope thereof as defined according to appended claims.

Claims

1) Catheter (14, 17) for the treatment through embolization with transcaval approach of a type I and type Il endoleak after the application of an endovascular stent graft (11) for endovascular treatment of an aneurysm (12) of the abdominal aorta (10) characterised in that it comprises an exit hole (20, 21) for a cannula having a 40° to 90° variable angle with respect to catheter body.

2) Catheter (14, 17) according to claim 1 , characterized in that said exit hole (20, 21) has a 40° to 60° variable angle with respect to the catheter body.

3) Catheter (14, 17) according to claim 1 or 2, characterized in that it further comprises a distal probe (16, 18) for intravascular endoluminal echography by ultrasound technology (IVUS).

4) Catheter (14, 17) according to any of preceding claims, characterized in that the advancement of said cannula (15, 19) outside of the catheter (14, 17) is adjustable using the external handle of said catheter (14, 17).

5) Catheter (14) according to any of preceding claims, characterized in that it further comprises a stabilizing balloon localised at 180° with respect to the exit hole (20) of said cannula (15).

6) Catheter (17) according to any of preceding claims, characterized in that it has a folded portion (22) having a 40° to 90° angle with respect to the body (23) of catheter (17) and a subsequent distal portion (24), parallel to the body (23) of catheter (17), at the distal end of said folded portion (22) being present an exit hole (21) of said cannula (19), in turn provided with a flexible stylet.

7) Catheter (17) according to claim 6, characterized in that said portion (22) is folded with an angle from 40° to 60° with respect to the body (23) of catheter (17)