Prevention of Aortic Dissection Suggests a Diameter Shift to a Lower Aortic Size Threshold for Intervention

Abstract

Background: Multiple studies have quantified the relationship between aortic size and risk of dissection. However, these studies estimated the risk of dissection without accounting for any increase in aortic size from the dissection process itself. Objectives: This study aims to compare aortic size before and after dissection and to evaluate the change in size consequent to the dissection itself. Methods: Fifty-five consecutive patients (29 type A; 26 type B) with aortic dissection and incidental imaging studies prior to dissection were identified and compared to a control group of aneurysm patients (n = 205). The average time between measurement at and prior to dissection was 1.7 ± 1.9 years (1.9 ± 2.0 years mean inter-image time in the control group). A multivariate regression model controlling for growth rate, age, and gender was created to estimate the effect of dissection itself on aortic size. Results: The mean aortic sizes at and prior to dissection were 54.2 ± 7.0 and 45.1 ± 5.7 mm for the ascending aorta, and 47.1 ± 13.8 and 39.5 ± 13.1 mm for the descending aorta, respectively. The multivariable analysis revealed a significant impact of the dissection itself (p < 0.001) and estimated an increase in size of 7.65 mm (ascending aorta) and 6.38 mm (descending aorta). Thus, a proportional estimate of 82.8% (ascending aorta) and 80.8% (descending aorta) of dissections are made at a size lower than the guideline-recommended threshold (55 mm). Conclusions: The aortic diameter increases substantially due to aortic dissection itself and, thus, aortas are being dissected at clinically meaningfully smaller sizes than natural history analyses have previously suggested. These findings have important implications regarding the size at which the risk of dissection is increased.

Ascending Aortic Diameter after Dissection Does Not Reflect Size before Dissection

“…By reviewing the literature, three similar studies were found. 2 , 3 , 4 Rylski et al 2 included 27 patients with spontaneous AAD and 36 with retrograde type B dissections. Patients with pre-AAD scans older than two years were excluded.…”

“…Mansour et al. 4 included 29 patients with AAD. Annual growth, gender, and age were accounted for by multiple regressions.…”

“…Patients with enlarged ascending aortas (> 40 mm in diameter) are regularly seen in outpatient clinics, and referred for surgery once the aortic diameter exceeds 50 – 60 mm. 1 Although three small studies have demonstrated that aortic diameters may increase acutely after dissection, 2 , 3 , 4 current guidelines for prophylactic resection rely on data derived from patients with AAD. 1 , 5 , 6 …”

Aortic Size and Aortic Dissection: Does One Size Fit All?

“…After controlling for aneurysm growth, gender, and age, multivariate analysis revealed that the diameter of the ascending aorta increased by 7.65 mm, due solely to type A dissection, and the diameter of the descending thoracic aorta increased by 6.38 mm, due solely to type B dissection. Rylski et al [2] reported similar findings; however, among others, they did not correct aortic diameter for aneurysmal growth at the time of aortic dissection, as did Mansour et al [1]. This observation, even though it was made in a small number of patients, may obviously have important clinical implications, because indications for interventional therapy (surgical or percutaneous) are mostly based on the size of the aorta at the time of dissection, with only limited information being available for the size of the aorta just prior to this catastrophic event [3,4,5,6,7,8,9,10,11,12].…”

“…In this issue of Cardiology , Mansour et al [1], from the Aortic Institute at Yale-New Haven Hospital, Yale University School of Medicine, New Haven, CT, USA, have suggested that the aortic diameter increases substantially at the time of aortic dissection due to the dissection itself. They studied 55 patients with aortic dissection (29 of type A and 26 of type B, according to the Stanford classification) and compared them to a control group consisting of patients with aortic aneurysm without dissection.…”