The Impact of the Morphologic Characteristics of Type B Aortic Dissection in the Acute Phase on the Aortic Enlargement in the Late Stage

Abstract

Objectives: According to the International Registry of Acute Aortic Dissection, >70% of patients with type-B aortic dissection (AD) have delayed aortic growth. The objective of this study was to investigate the morphologic characteristics of aortic enlargement in type-B AD. Methods: A total of 120 patients with uncomplicated acute type-B aortic dissection (uATBAD) were divided into 4 groups according to the presence of a patent or thrombosed false lumen (FL) with or without aortic enlargement. In all groups, the area of the true lumen (TL) and the FL were measured on axial computed tomography images. Results: A total of 120 uATBAD patients were evaluated: patent FL with (PE, N = 28, 23%) or without aortic enlargement (PU, N = 17, 14%) and thrombosed FL with (TE, N = 34, 28%) or without enlargement (TU, N = 41, 34%). The initial aortic diameter was not significantly different among the 4 groups (PE vs. PU = 39 ± 8 vs. 37 ± 10 (p = 0.354); TE vs. TU = 38 ± 6 vs. 37 ± 6 (p = 0.391)). The area of the FL tended to be larger in the PE group. In contrast, the area of the TL was significantly larger in the TE group. Late outcomes of uATBAD treated with optimal medical treatment were acceptable. Conclusions: In patients with uATBAD and a thrombosed FL, the patients with aortic enlargement tended to be increased TL size. In contrast, in patients with a patent FL, the patients with aortic enlargement tended to be increased FL size.