Endovascular versus medical management of type B intramural hematoma: a meta-analysis

Background: Aortic intramural hematoma constitutes one of the three classifications of acute aortic syndrome (AAS). Type B intramural hematoma (IMH-B) is localized to the descending thoracic aorta and can be managed through medical, endovascular or surgical means. Data comparing contemporary management with thoracic endovascular aortic repair (TEVAR) versus traditional medical management (MM) is sparse and only moderate strength recommendations for TEVAR are provided in guidelines. This meta-analysis aimed to pool available data from comparative studies between TEVAR and MM and examine differences in outcomes.
Methods: Literature search of electronic medical databases was conducted to identify studies comparing TEVAR and MM for management of IMH-B. Data extraction from studies fulfilling the inclusion criteria was performed by two authors and meta-analysis using a random-effects model applied to pool baseline data and examine risk ratios (RR) for management outcomes.
Results: Of the initial 2,349 studies, nine studies were identified for analysis. There were 161 TEVAR patients and 166 who were medically managed. The mean age of the cohort was 62.2 years [95% confidence interval (CI): 55.8–68.7 years]. Patients with complicating features of IMH-B at presentation were more likely to appear in the TEVAR group, with more penetrating atheromatous ulcer (PAU) [risk difference (RD), 0.565, 95% CI: 0.240–0.889, P=0.001], ulcer-like projection (ULP) (RD 0.240, 95% CI: 0.965–0.384, P=0.001), and greater IMH size (mean difference, MD 5.47 mm, 95% CI: 0.320–10.6, P=0.037). There was no statistical difference between TEVAR and MM for the primary endpoints of aortic-related death (RR 0.535, 95% CI: 0.191–1.5, P=0.234) or IMH-B regression (RR 1.25, 95% CI: 0.859–1.81, P=0.246). Of the secondary endpoints, TEVAR had both significantly less dissection during follow-up (RR 0.295, 95% CI: 0.0881–0.989, P=0.048) and less rupture during follow-up (RR 0.206, 95% CI: 0.0462–0.921, P=0.039).
Conclusions: A small number of series comparing TEVAR and MM for management of IMH-B are available and random-effects meta-analysis did not reveal any statistically significant difference between treatments for aortic related death or IMH-B regression at a mean follow-up of 37 months. TEVAR was found to be associated with lower risk of dissection and lower risk of rupture during follow-up. Baseline data meta-analysis showed patients with complicating features of PAU, ULP, and larger IMH size were more likely to be managed with TEVAR.