Stent Grafting Acute Aortic Dissection: Comparison of DeBakey Extent IIIA Versus IIIB

Background. Thoracic endovascular aortic repair (TEVAR) with stent grafting is effective for acute dissection in selected patients, but most remain at risk for reintervention. The effect of the extent of dissection on outcome is unclear. Objectives of this study were to compare characteristics, outcomes, and aortic remodeling after TEVAR between patients with DeBakey extent IIIA and IIIB dissection. Methods. From 2005 to 2013, 520 patients presented with acute aortic syndrome. TEVAR was performed in 108 (41 IIIA, 67 IIIB) during the acute phase. Detailed three-dimensional computed tomography imaging analysis was performed in all patients. Results. Patients with IIIA dissection were older (69.9 +/- 10 vs 59.5 +/- 13 years; p < 0.001) and more likely to have had prior cardiovascular operations (p = 0.01) than IIIB. The most common indication for TEVAR was ischemia in IIIB (66%), and pain (34%) in IIIA. Rupture was more common in IIIA (24.3% vs 1.5%; p < 0.001). Aortic diameters were similar between groups, but IIIB patients had smaller true/false lumen ratio (0.89 +/- 1.08 vs 1.76 +/- 1.27; p = 0.003). Stent graft coverage was 152 +/- 42 mm for IIIA vs 212 +/- 85 mm for IIIB (p < 0.001). Additional branch stents were used in 20 IIIB patients (30%), and 7 had infrarenal stenting. Early mortality and complications were similar between groups, except for renal failure (4.4% IIIB vs 0% IIIA; p = 0.04). Mean follow-up was 30 +/- 28 months. Estimated survival at 1, 3 and 5 years was 84%, 65%, and 38% for IIIA, and 70%, 66%, and 59% for IIIB, respectively, with no significant difference. Significant expansion of the true lumen occurred in both groups after stenting, and the aortic and false lumen diameter increased only at the level of the abdominal aorta in IIIB patients. The false lumen was thrombosed in 91% of IIIA vs 62% of IIIB patients at the mid-descending aorta. Intervention was required in 15% (6 of 39) of IIIA and in 26% (15 of 58) of IIIB patients. Conclusions. In patients requiring TEVAR for acute dissection, patient factors and aortic morphology differ by the extent of the dissection. Aortic remodeling after TEVAR was better in patients with limited extent (IIIA) dissection than in than patients with extensive (IIIB) dissection. Despite these differences, very little difference was noted in early and late outcomes, which may be explained by differences in patient characteristics. (C) 2016 by The Society of Thoracic Surgeons