Observations on the failure of stent-grafts in the aortic arch.

INTRODUCTION: The results of endovascular stent-grafts in the abdominal aorta and descending thoracic aorta have been encouraging. Expanding the use of thoracic stent-grafts in to the aortic arch has been associated with increasing numbers of complications. Recently isolated cases of stent-graft collapse have been reported. METHODS: This was a multi-centre European case series. Data was collected retrospectively on seven patients from five experienced endovascular centres with thoracic stent-graft collapse. RESULTS: Of the seven patients four were treated for traumatic aortic rupture. Six were male, median age 33 (range 17-54) years. During the ensuing 2 months all patients suffered stent-graft collapse. This was symptomatic in 3 patients and the rest were identified on CT. Endovascular management was possible in 6/7 patients using either a balloon expandable stent (n=6) or further stent-graft (n=1). Two patients had persistent type I endoleak despite treatment. Two of the 7 patients died, both of which presented with symptomatic thoracic stent-graft occlusion. Both deaths were a direct result of stent-graft collapse. CONCLUSIONS: Thoracic stent-graft collapse may be asymptomatic underscoring the importance of stent-graft surveillance. Endovascular management of collapse is possible in most cases using a large balloon expandable stent. Symptomatic collapse is associated with high morbidity and mortality.

First-generation aortic endografts: analysis of explanted Stentor devices from the EUROSTAR Registry.

PURPOSE: To examine the structure and healing characteristics of chronically implanted Stentor endografts that were explanted due to migration, endoleak, thrombosis, or aneurysm expansion. METHODS: The devices were harvested following reoperation (n = 5) or autopsy (n = 1) with implantation times ranging from 13 to 53 months. Structural modifications to the metal components were examined using radiography, endoscopy, and magnetic resonance imaging (MRI). Specimens taken from components of the modular stent-grafts were examined histologically and with scanning electron microscopy (SEM) to assess healing behavior. Physical and chemical stability of the nitinol wires and woven polyester graft material was evaluated using SEM and electron spectroscopy for chemical analysis. RESULTS: Although the endografts were retrieved for a variety of reasons, they exhibited similar healing and structural modifications. The woven polyester sleeve showed evidence of yarn shifting and distortion, yarn damage, and filament breakage leading to the formation of openings in the fabric. The luminal surface endografts showed incomplete healing characterized by a poorly organized, nonadherent thrombotic matrix of variable thickness. Radiographic and endoscopic observations indicated that structural failure of the grafts, particularly in the main aortic component, was related to severe compaction and dislocation of the metallic frame due to suture breaks. Corrosion marks were observed on some nitinol wires in all devices. Chemical analysis and ion bombardment of the nitinol wires revealed that the surface concentrations of titanium and nickel were not homogenous. The first layer was composed of carbon or organic elements, followed by a stratum of highly oxidized titanium with a low nickel concentration; the titanium-nickel alloy lay beneath these layers. CONCLUSIONS: Although the materials selected for construction of endovascular grafts appears judicious, the assembly of these biomaterials into various interrelated structures within the device requires further improvement.

[Endovascular treatment of abdominal aorta aneurysms using bifurcated endoprosthesis]. / Tratamiento endovascular de los aneurismas de aorta abdominal con endoprótesis bifurcadas.

OBJECTIVE: To obtain an initial assessment of the implantation technique of bifurcated vascular endoprothesis in the treatment of abdominal aorta aneurysms (AAA). METHODS: Eleven Vanguard type endoprostheses were implanted in eleven patients with infra-renal aortic aneurysm. The technique was performed with surgical approach in one femoral artery, and percutaneously in the other. The procedure was performed with epidural anesthesia. RESULTS: A technical success--i.e., the exclusion of the aneurysm--was obtained in all cases. No technical complications occurred during the procedure. Three patients had low degree contrast leak in the angiographic control immediately after the procedure. Eight patients had low grade fever in the immediate follow-up which resolved with medical therapy, two patients had hematomas in the approach sites, one renal infarction, one ileus for two days, another one for five days, and three patients had lymphatic effusion. During follow-up the patients with leak had to undergo co-axial endoprosthesis implantation. CONCLUSIONS: It is our view that bifurcated vascular endoprostheses offer a valid alternative in the treatment of AAA. The procedure can be performed with epidural anesthesia and sedation, with a low rate of complications. The long term follow-up and the perfecting of the approach and resection systems will ultimately dictate their usefulness in this and other vascular conditions.

[Arteriovenous malformation of the superior mesenteric artery with secondary portal hypertension]. / Malformación arteriovenosa de la mesentérica superior con hiperaflujo e hipertensión portal secundaria.

The case of a 60-year-old patient who was repeatedly admitted for ascitic decompensation secondary to hyperflow portal hypertension provoked by congenital arteriovenous malformation of the superior mesenteric artery is presented. Diagnosis was performed by arteriography. Surgical treatment was conducted with total resection of the malformation thereby achieving complete resolution and normalization of portal pressure. The literature is reviewed and the pathophysiologic mechanism as well as the clinical manifestations, diagnosis and treatment are discussed.

Popliteal artery and venous aneurysm as a complication of arthroscopic meniscectomy.

A 29-year-old man presented a 2-week history of right popliteal fossa and leg swelling following an arthroscopic meniscectomy. Roentgenographic evaluation showed an arterial and venous aneurysm at the popliteal level, with an associated arteriovenous fistula. Popliteal aneurysm in young men is very rare and generally related to open surgical techniques; incidence with arthroscopic techniques is extremely infrequent.