Abstract 4136604: Efficacy of angiotensin receptor blockers in thoracic aortic aneurysm: meta-analysis of randomized controlled trials

Background: Thoracic aortic aneurysm (TAA) poses a significant risk of aortic dissection and mortality. Angiotensin receptor blockers (ARBs) have been proposed as a potential therapeutic intervention to mitigate these risks but their effects are uncertain. Aim: To evaluate the efficacy of ARBs in patients with TAA. Methods: A comprehensive search of Cochrane CENTRAL, Ovid Medline R, Pubmed, and Web of Science yielded 2563 records, from which 8 unique randomized controlled trials (RCTs) (including 7 Marfan and 1 bicuspid aortic valve+TAA populations) comprising 1575 patients were included in the analysis. The primary outcome measures were aortic dissection and all-cause mortality. Pooled risk ratios (RR) or mean differences (MD) in an inverse variance random-effects model were generated and analyses were performed with “meta” package in R (version 4.3.2). Results: Our analysis reveals no significant beneficial effect of ARBs on aortic dissection (RR 0,62 [95%CI, 0,20; 1,92], I 2 :0%) and all-cause mortality (RR 0,61 [95%CI, 0,18; 2,05], I 2 :0%), irrespective of specific ARB agents (including losartan, irbesartan, and telmisartan), comparators (beta blocker, placebo, or no treatment), disease condition (Marfan syndrome or bicuspid aortic valve), and patient demographics (children or adults). Additionally, there were no significant differences observed between ARB and control groups in changes in ascending aorta and aortic annulus diameter, as well as aortic Z-score at the 3-year mark, including the annual change in ascending aorta (MD 0.04 mm/year [95% CI, -0.07 to 0.15], I 2 :0%) and aortic root diameter (MD -0.06 mm/year [95% CI, -0.22 to 0.10], I 2 :81%) by echocardiography. However, there was a significant reduction in aortic root diameter as assessed by MRI (MD -0.48 mm/year [95%CI, -0.89 to -0.08]) and echocardiography (MD -0.51 mm/3year [95%CI, -0.85 to -0.17]), with low heterogeneity when compared with control. Risk of aortic surgery and severe adverse events were also comparable. Conclusion: We found no significant beneficial effect of ARBs in reducing the risk of aortic dissection or all-cause mortality in patients with TAA. Despite observing a significant reduction in the aortic root diameter by MRI and echocardiography with ARB therapy, other imaging outcomes were comparable between ARB and control groups.