Late aortic remodeling persists in the stented segment after endovascular repair of acute complicated type B aortic dissection

Abstract

Thoracic endovascular aortic repair (TEVAR) for acute complicated type B aortic dissection (AD) promotes early positive aortic remodeling. However, little is known about the long-term effect of TEVAR on the dissected aorta, which is the goal of this study. Between August 2005 and August 2009, 31 patients with complicated type B AD were treated with TEVAR and had >1-year follow-up imaging. Computed tomography angiograms obtained at 1 month, 1 year, and long term (average, 42 months) were compared with baseline scans. The largest diameters of the stented thoracic aorta, stented true lumen, and stented false lumen were recorded at each time point, as were the values in the unstented distal thoracic aorta and the abdominal aorta. Changes over time were evaluated by a mixed effect analysis of variance model of repeated measures. The average age of the cohort was 56 years, and 74% were male. Indications for TEVAR were as follows: 61% malperfusion, 32% refractory hypertension, 45% impending rupture, and 32% persistent pain; 58% had more than one indication. All patients were treated in the acute phase within 7 days of the initial presentation. The average length of aorta covered was 19 cm. Observation of the stented segment over time showed that the maximum diameter of the stented thoracic aorta was stable (P = NS), the diameter of the stented true lumen increased (P < .001), and the diameter of the stented false lumen decreased (P < .001); 84% had complete false lumen obliteration across the stented aortic segment. Observation of the uncovered thoracic aorta over time showed that the maximum diameter increased (P = .014), as did the visceral segment of the aorta (P < .001). The average growth of the visceral segment was 31% in patients with a patent false lumen vs 3% in those with a thrombosed false lumen (P = .004). One patient had aneurysmal degeneration of the false lumen and required an additional endograft at 18 months. TEVAR of acute AD promotes long-term remodeling across the stented segment, with false lumen obliteration in 84% of patients. However, false lumen obliteration beyond the stented segment appears necessary to prevent late aneurysmal degeneration of the distal aorta.