Aortic wall thickness in patients with ascending aortic aneurysm versus acute aortic dissection

Recent studies have shown that aortic diameter alone is an insufficient parameter to identify patients at risk for aortic dissection. The aim of this study was to determine the value of the ratio of aortic diameter to medial wall thickness as a new marker of risk.

We obtained data from 181 patients with an ascending aortic aneurysm (n = 94) or an acute type A aortic dissection (n = 87), surgically treated at our institution (1996-2012). Measurements of the maximum aortic diameter and the medial wall thickness were conducted by retrospective review of preoperative imaging studies and histological specimens, respectively.

Nearly 60% of the dissection patients had aortic diameters smaller than 50 mm. There was a significant negative linear correlation between medial wall thickness and aortic diameter (P = 0.01) in the dissection group only. Among patients with aortic diameters above 50 mm, dissection patients had significantly thinner aortic media (P = 0.04). Among patients with a mildly dilated aorta (>45 mm), the aortic diameter to medial wall thickness ratio was significantly higher in the dissection group (P = 0.04).

Among patients with a dilatation of the ascending aorta of more than 45 and 49 mm, patients experiencing aortic dissection have a significantly higher aortic diameter to wall thickness ratio and a thinner aortic media, respectively. In the subset of patients with mild aortic dilatation, wall thickness might in the future serve as an additional parameter to help identify those patients who would benefit from prophylactic aortic surgery.