Aortic Anatomy and Complications of the Proximal Sealing Zone after Endovascular Treatment of the Thoracic Aorta.

BACKGROUND: Technical and clinical success of thoracic aortic endovascular procedures relies mainly on the choice of the proximal sealing zone (PSZ). The latter can be affected by multiple complications, all of them having a potential gravity and a direct link with the quality of the PSZ. The objective of this study was to analyze the risk factors of PSZ complications occurrence. METHODS: Between 2007 and 2015, all the patients treated by a thoracic stent graft in zones 2, 3, or 4 were retrospectively reviewed, with analysis of the preoperative and postoperative angio-computed tomography. Proximal sealing zone complications are type Ia endoleaks, bird beak ≥20 mm, malposition ≥11 mm, migration ≥10 mm, and retrograde dissection. Three types of potential risk factors were analyzed: (1) related to the patients (age, gender, pathology, urgency, hybrid surgery); (2) related to the stent graft (bare or covered proximal stent, degree of oversizing, number of stents, generation); (3) related to the morphology (radius of curvature, diameter, degree of conicity, calcifications and thrombus of the neck, depth of the arch, angulation of the proximal sealing zone, and tortuosity index of the arch and the thoracic aorta. RESULTS: Seventy-six patients (mean age: 54 years, 17-93 years) were treated for traumatic aortic rupture (n = 27, 35.5%), aortic dissection (n = 26, 34%), aneurysm (n = 15, 20%), and other diseases (floating thrombus, aortoesophageal fistula) (n = 8, 10.5%). A hybrid surgery was carried out in 18 patients (24%). Primary technical success was 93.5% (n = 71). With a mean follow-up of 29 months, 30 PSZ complications were observed in 21 patients (28%): type Ia endoleaks (n = 3, 4%), bird beak (n = 7, 9%), malposition (n = 3, 4%), migration (n = 1, 1.5%), retrograde dissection (n = 1, 1.5%), or several complications (n = 6, 7.8%). Among the morphological factors, 2 parameters were significantly associated with the occurrence of complications: tortuosity index (group without PSZ complications 1.62 ± 0.2 vs. group with PSZ complications 1.72 ± 0.2, P = 0.042), and the diameter of the proximal neck (group without PSZ complications 25.7 ± 5 vs. group with PSZ complications 31 ± 6.0, P = 0.001). Neither the demographic factors nor those related to the stent graft presented a statistically significant relation with the occurrence of complications. CONCLUSIONS: This work clearly highlights the relation between PSZ complications, independently of their type, and the local and global aortic morphology. A wide proximal neck, > 34 mm, and an important aortic tortuosity, > 1.8, are situations at risk.

Atheromatous occlusive lesions of the popliteal artery treated with stent grafts: predictive factors of midterm patency.

BACKGROUND: Because of its location, the popliteal artery is exposed to important biomechanical constraints, inducing a specific risk of thrombosis of stents, little studied in the literature. The objective of this monocentric retrospective study was to evaluate the patency of stents implanted in the popliteal artery to treat atheromatous lesions and the risk factors predisposing to thrombosis. METHODS: Between January 2009 and July 2013, all the patients receiving stents for a residual stenosis or a complication of angioplasty in the popliteal artery or the distal anastomosis of a femoropopliteal bypass were included retrospectively and in an intention to treat. Forty-six patients (17 women), with a 71.5 years median age (range, 45-90 years), including 17 diabetic patients (37%) and 7 hemodialysis patients (15%), were operated in 51 limbs for claudication (n = 25, 49%), critical ischemia (n = 18, 35%), or acute ischemia (n = 8, 16%). Thirty stenoses >70% (59%) and 21 thromboses (41%) were treated with 56 autoexpandable stents, with an average diameter of 6 mm (range, 5-8 mm) and an average length of 5 cm (range, 4-15 cm), including 39 lesions in P1 (above the patella), 8 in P2 (articular), and 4 in P3 (distal popliteal artery). The following factors were analyzed according to univariate and multivariate models: age, gender, Society for Vascular Surgery score, symptomatology, type and location of lesion, number of stents deployed, and dimension of stents. RESULTS: Technical success was of 98% (n = 50), including 1 insufficient result of the endovascular treatment. At 30 days, one patient treated for critical ischemia died (2%) and one residual popliteal stenosis was treated by bypass (2%). After a 27.6 ± 10.07 month follow-up, restenosis (>50%) was detected in 5 cases including 4 asymptomatic and a popliteal thrombosis occurred in 9 cases, including 3 asymptomatic cases. Eight secondary interventions were necessary, including 4 endovascular procedures, 3 bypasses, and only 1 major amputation (thigh). The primary and secondary patencies at 12 months and 24 months were 80% and 65%, and 90% and 74%, respectively. The multivariate analysis showed that the type of lesion (stenosis versus occlusion; odds ratio [OR], 5.1; 95% confidence interval [CI], 1.2-22.9, P = 0.032) and the number of stents implanted (1 vs. 2 stents; OR [95% CI], 12.7 [1.8-88.5]; P = 0.011) were independent predictive factors of secondary thrombosis. CONCLUSIONS: The endovascular treatment of the atheromatous popliteal lesions appears to be a satisfactory alternative. The implantation of 1 stent in the popliteal artery is recommended in the event of popliteal occlusion, whereas for a stenosis, it must be reserved for patients with residual stenosis or in the event of complications of angioplasty, such as dissection or elastic recoil. Stent must be single, with deployment of a long stent in the event of long lesion.