Evaluation of the Valiant Mona LSA Thoracic Stent Graft System in Thoracic Aortic Aneurysms and Chronic Dissections

To ensure adequate seal of currently available stent grafts, a proximal 20 mm of healthy aorta is recommended. Extending the proximal landing zone into the arch by intentional covering of the left subclavian artery (LSA) without revascularization expose to serious neurologic complications. Serious risks are also known to accompany subclavian revascularization. The Valiant Mona LSA Thoracic Stent Graft System (Medtronic,Santa Rosa, Calif) consists of a main stent graft and a branch stent graft designed to maintain LSA patency. The purpose of this study is to characterize the safety and effectiveness of this device for the treatment of Aneurysms and chronic Type B dissections of the arch.

Stent graft coverage of the left subclavian artery (LSA) may be required to achieve an adequate landing zone in up to 40% of descending thoracic aneurysms (DTAs). To ensure adequate seal of currently available off-the-shelf stent grafts, 20 mm of healthy aorta is recommended between the proximal neck of the aneurysm and the leading edge of the stent graft. Stent graft placement can be facilitated by extending the proximal landing zone into the arch and covering the LSA; however, there may be a higher risk of serious neurologic outcomes (cerebral and paraplegia), although this is still a matter of debate. Serious risks are also known to accompany subclavian revascularization, which may involve bypass or transposition. The Valiant Mona LSA Thoracic Stent Graft System (Medtronic,Santa Rosa, Calif) consists of a main stent graft and a branch stent graft designed to maintain LSA patency while diverting circulation through the encroaching aneurysm.

The purpose of the feasibility study is to characterize the safety of the Valiant Mona LSA Thoracic Stent Graft System, including an assessment of the safety and effectiveness of the device acutely and at the 1-month visit in the identified subject population (Aneurysms and chronic, Type B dissections). A follow up of this population will be annually during 5 years.

This pilot, non-randomized, single-arm prospective study will concern 20 patients. Inclusion criteria required patients with a thoracic aortic aneurysm (TAA) or dissection with an indication of a stent-Graft insertion. Primary end points will be aneurysm-related mortality, stroke, paraplegia, left arm/hand ischemia, and treatment success. Technical success will be assessed by imaging at 1 month, 6 months then annually during 5 years.

Eligibility Criteria:
Inclusion Criteria:

* Subject is at least 18 years of age.
* Subject understands and has signed an Informed Consent
* Subject must be considered a candidate for revascularization of the LSA.
* Subject must be able to tolerate a surgical revascularization of the LSA.
* Subject has a descending thoracic aneurysm (DTA) which will require coverage of the LSA
* Subject has a healthy, non-diseased aortic proximal seal zone of at least 10 mm from the left carotid to the LSA and at least 5 mm landing zone distal to the LSA and proximal to the start of the aneurysm/ulcer/or the proximal entry tear for dissection.
* Subject has a non-diseased aortic diameter between 25 mm and 42 mm (fusiform/saccular aneurysms or penetrating ulcers) or 28 mm to 44 mm (chronic type B dissections),
* Subject has a LSA with a diameter between 8 mm and 13 mm.
* Subject has sufficient landing zone within the LSA to accommodate the BSG without occlusion of any significant vessels
* Subject has patent brachial arteries, iliac or femoral arteries (without circumferential calcifications and a diameter of ≥ 10mm), or can tolerate a conduit that will allow endovascular access to the aneurysmal site with the delivery system of the appropriate sized device chosen for treatment.
* Subject has a condition requiring prospective revascularization of the LSA

Exclusion Criteria:

* Subject has an aneurysmal, tortuous, or atherosclerotic LSA, conflicting the branch graft insertion.
* Subject has an aortic atheroma classified as grade IV or grade V.
* Subject has prohibitive calcification, occlusive disease, or tortuosity of intended fixation sites.
* Treatment with the Valiant Mona LSA Thoracic Stent Graft system would require intentional coverage of the left common carotid artery with the stent graft fabric.
* Subject has significant and/or circumferential aortic mural thrombus at either the proximal or distal attachment sites that would compromise fixation and seal of the device.
* Subject is a pregnant or breastfeeding female.
* Subject has a known allergy or intolerance to the device components.
* Subject is in acute renal failure or has renal insufficiency with a serum creatinine ≥ 2.0 mg/dL or is on dialysis.
* Subject has coronary artery disease with unstable angina and has not received treatment.
* Subject has a connective tissue disease (e.g. Marfan's syndrome, medial degeneration).
* Subject has active systemic infection and/or a mycotic aneurysm.
* Subject is currently participating in an investigational drug or device clinical trial that would interfere with the observations of this study.
* Subject has other medical, social, or psychological problems that, in the opinion of the investigator, will interfere with treatment and follow-up procedures.
* Subject has a life expectancy of less than 1 year.
* Subject has a history of bleeding diathesis, coagulopathy, or refuses blood transfusion.
* Subject has a known hypersensitivity or contraindication to anticoagulants or contrast media, which is not amenable to pre-treatment.