Aortic remodeling after endovascular repair with stainless steel-based stent graft in acute and chronic type B aortic dissection

Abstract

This study analyzes the experience of a single center using hybrid stainless steel-based endovascular stent graft repair of acute complicated and chronic type B aortic dissection aneurysm, and assesses the proximal and distal aortic morphologic changes of the midterm results. Between November 2006 and March 2011, 61 patients with type B aortic dissection underwent stainless steel-based stent graft repair and were divided into an acute complicated dissection group (AD; n = 33) and a chronic dissection aneurysm group (CD; n = 28). Serial computed tomography (CT) images were obtained to evaluate the changes of true and false lumen diameter at four levels during the postoperative period. The stent graft was successfully implanted in all patients (100%), with two surgical mortalities in the AD group and low perioperative morbidity (3.6%) of stroke and paraplegia. The cumulative survival rates of the two groups were similar (77.6% and 89.0%; P = .585) in a mean follow-up period of 24.1 ± 15.6 months. Complete thrombosis of the thoracic false lumen down to the diaphragm level was achieved in 80.6% of the patients in the AD group and 88.5% in the CD group without significant difference (P = .221), but the complete regression rate of the thoracic false lumen down to the diaphragm level showed a tendency of propitious remodeling in the AD group (54.8% vs 30.8%; P = .068). During follow-up, despite the proximal changes of stented true and adjacent false lumen diameter being significantly increased and decreased, respectively, in both acute and chronic settings (P < .05), they were less prominent at the distal aorta in the CD aneurysm group. Intimomedial erosion of the distal end of the stent graft occurred in both acute (n = 6; 18.9%) and chronic (n = 10; 35.7%; P = .121) dissection settings after mean follow-up of 14.0 ± 4.8 months in the AD group and 24.8 ± 5.9 months in the CD group. Three patients with chronic dissection developed either pseudoaneurysm or true lumen compromise by expanded false lumen thrombi and required re-endografting. Endovascular stainless steel-based stent graft implantation with vascular bypass to gain a sufficient proximal landing zone is feasible for type B aortic dissection and has low early and midterm mortality and morbidity in both the acute and chronic phases. Although early intervention might result in more favorable aortic remodeling with a higher possibility of complete regression and lower risk of late distal erosion, longer-term follow-up still necessitates continuous careful surveillance of the entire aorta, especially the distal condition.