Lack of an effective drug therapy for abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) rupture is a common cause of death in adults. CurrentAAAtreatment is by open surgical or endovascular aneurysm repair. Rodent model and human epidemiology, and genetic and observational studies over the last few decades have highlighted the potential of a number of drug therapies, including medications that lower blood pressure, correct dyslipidaemia, or inhibit thrombosis, inflammation or matrix remodelling, as approaches to managing smallAAA. This review summarizes priorAAApathogenesis data from animal and human studies aimed at identifying targets for the development of drug therapies. The review also systematically assesses past randomized placebo-controlled drug trials in patients with smallAAAs. Eleven previously published randomized-controlled clinical trials testing different drug therapies aimed at slowingAAAprogression were identified. Five of the trials tested antibiotics and three trials assessed medications that lower blood pressure. Meta-analyses of these trials suggested that neither of these approaches limitAAAgrowth. Allocation to blood pressure-lowering medication was associated with a small reduction inAAArupture or repair, compared to placebo (relative risk 0.94, 95% confidence intervals 0.89, 1.00,P = 0.047). Three further trials assessed the effect of a mast cell inhibitor, fibrate or platelet aggregation inhibition and reported no effect onAAAgrowth or clinical events. Past trials were noted to have a number of design issues, particularly small sample sizes and limited follow-up. Much larger trials are needed to properly test potential therapeutic approaches if a convincingly effective medical therapy forAAAis to be identified.