A FENESTRATED ENDOPROSTHESIS FOR THE CORRECTION OF AORTIC ANEURYSMS

Abstract

A fenestrated endoprosthesis for the correction of aortic arch aneurysms comprising: a stent (20) having a first oblong lateral hole (23) having an area equal to the total area occupied by the innominate artery (11) and by the carotid artery (12); said stent (20) comprises a metal skeleton (21) covered with a fabric (22); characterized by comprising a flexible sac (30) that covers said stent (20) covered with fabric (22); said sac (30) comprises a second lateral hole (32) having an area larger than said first hole (23), so that the edges (26) of said stent (20) covered with fabric (22) that delimit said first hole (23) are visible; the edges (33) of said sac (30) that delimit the hole (32) are welded to said stent (20) covered with fabric (22); a volume (31) is created between said stent (20) covered with fabric (22) and said sac (30); said volume (31) is filled with a polymer.

Claims

1. A fenestrated endoprosthesis for the correction of aortic arch aneurysms comprising: a stent (20) having a first oblong lateral hole (23) having an area equal to the total area occupied by the innominate artery (11) and by the carotid artery (12); said stent (20) comprises a metal skeleton (21) covered with a fabric (22); characterized by comprising a flexible sac (30) that covers said stent (20) covered with fabric (22); said sac (30) comprises a second lateral hole (32) having an area larger than said first hole (23), so that the edges (26) of said stent (20), covered with fabric (22) that delimit said first hole (23), are visible; the edges (33) of said sac (30) that delimit the hole (32) are welded to said stent (20) covered with fabric (22); between said stent (20) covered with fabric (22) and said sac (30) a volume (31) is created; said volume (31) is filled with a polymer.

2. The endoprosthesis in accordance with claim 1, characterized in that said stent (20) covered with fabric (22) comprises two radiopaque orientation markers (24) and (25) positioned at the end edges of said first oblong hole (23).

3. The endoprosthesis in accordance with claim 1, characterized in that said polymer is a thermosetting polymer composed of a biocompatible and biostable blend based on polyethylene glycol (PEG).

4. The endoprosthesis in accordance with claim 1, characterized in that said sac (30) is made of polyurethane.

5. The endoprosthesis in accordance with claim 1, characterized in that the edges of said sac (30) are welded at proximal level (35) and at distal level (34) to said stent (20) covered with fabric (22).

6. The endoprosthesis in accordance with claim 5, characterized in that the edges (33) of said sac (30) are welded to said stent (20) covered with fabric (22) by means of a polyethylene suture.

7. The endoprosthesis in accordance with claim 1, characterized in that said fabric (22) is made of expanded polytetrafluoroethylene (PTFE).

8. A method for producing a fenestrated endoprosthesis for the correction of aortic arch aneurysms comprising the steps of: providing a stent (20) comprising a metal skeleton (21) made of nitinol covered in a fabric (22); making a first oblong lateral hole (23) in said stent (20) covered with fabric (22) having an area equal to the total area occupied by the innominate artery (11) and by the carotid artery (12); covering said stent (20) covered with fabric (22) with a flexible sac (30); making a second lateral hole (32) in said sac (30) having an area larger than said first hole (23), so that the edges (26) of said stent (20), covered with fabric (22) that delimit said first hole (23), are visible; welding the edges (33) of said sac (30) that delimit the hole (32) to said stent (20) covered with fabric (22); welding the edges of said sac (30) at distal level (34) of said stent (20) covered with fabric (22); filling a volume (31) that is created between said stent (20) covered with fabric (22) and said sac (30) with a polymer; welding the edges of said sac (30) at proximal level (35) of said stent (20) covered with fabric (22).

Description

[0014] The features and advantages of the present invention will be apparent from the following detailed description of a practical embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein:

[0015] FIG. 1 schematically shows a normal supra-aortic trunk;

[0016] FIG. 2 schematically shows a covered stent in accordance with the present invention;

[0017] FIGS. 3a and 3b schematically show a covered stent inclusive of an external sac, in a lateral and sectional view, in accordance with the present invention;

[0018] FIG. 4 schematically shows a supra-aortic trunk with an aneurysm;

[0019] FIG. 5 schematically shows a covered stent inclusive of an external sac placed in situ in accordance with the present invention.

[0020] The endoprosthesis comprises a covered stent 20 that has a metal skeleton 21, for example made of nitinol covered in a fabric 22, for example expanded polytetrafluoroethylene (PTFE).

[0021] The covered stent 20 has, in addition to the terminal holes, an oblong lateral hole 23 having an area equal to the total area of the aortic segment 10 occupied by the innominate artery 11 and by the left common carotid artery 12.

[0022] Two radiopaque orientation markers 24 and 25 placed at the end edges of said first oblong hole 23 must be defined on the covered stent 20, so that at the time of its positioning they are at the external origins of the innominate artery 11 and of the left common carotid artery 12.

[0023] The covered stent 20 is further covered externally by a sac 30, to form an endoprosthesis 40 in accordance with the present invention.

[0024] The sac 30 is substantially a flexible tube made of polyurethane, with inner sleeve made of polyester included.

[0025] An internal tubular volume 31 is created between the covered stent 20 and the sac 30, which are placed coaxially.

[0026] The sac 30 also has a lateral hole 32 coaxial to the hole 23 of the covered stent 20, having an area slightly larger than the total area occupied by the innominate artery 11 and by the carotid artery 12, so that they project from under the edges 26 of the covered stent 20 that delimit the hole 23.

[0027] The edges 33 of the sac 30 that delimit the hole 32 are welded to the covered stent 20 with a polyethylene suture.

[0028] The edges 34 of one end of the sac 30 are also welded to the covered stent 20, so as to have only one inlet 35 in the volume 31 that is created between the covered stent 20 and the sac 30.

[0029] If an aneurysm 41 is present, the endoprosthesis 40 is inserted into the aorta 41 by means of conventional methods, such as a release catheter.

[0030] The endoprosthesis 40 is positioned, checking its correct positioning, so that the two markers 24 and 25 are at the external origins of the innominate artery 11 and of the left common carotid artery 12.

[0031] Now, in accordance with the present invention, the volume 31 included between the covered stent 20 and the sac 30 must be filled with an amorphous material, such as for example a polymer that maintains a plastic state, such as the polymer used in breast implants, for example composed of a biocompatible and biostable blend based on polyethylene glycol (PEG).

[0032] Before inserting the polymer, it is preferable to measure the volume of polymer that is to be inserted, which is calculated on the basis of the difference between the overall volume of the aneurysm arch and the volume of the endoprosthesis 40 (i.e., the free space between endoprosthesis and aortic walls) with a transducer in the circuit that also allows the filling pressure to be measured as further verification.

[0033] In order to take the measurement a saline solution can be inserted and the volume inserted is calculated. In fact, the sac 30 is completely closed also around the fenestration, with the exception of a small inlet 35 (the edges can be sutured partially to leave this inlet).

[0034] Subsequently, a volume of polymer equal to the volume of saline solution, previously measured, will be inserted.

[0035] The polymer is inserted and the inlet 35 is then sutured completely by means of polyethylene.

[0036] The endoprosthesis thus conceived is susceptible to numerous modifications and variants, all falling within the scope of the inventive concept; moreover, all details can be replaced by technically equivalent elements.