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

OBJECTIVE: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.