Irbesartan slows aortic dilation, but doesn't reduce the rate of surgery in those with Marfan syndrome (AIMS)

Reference

Mullen M, Jin XY, Child A, et al, for the AIMS Investigators. Irbesartan in Marfan syndrome (AIMS): a double-blind, placebo-controlled randomised trial. Lancet 2019;394(10216):2263-2270.

Synopsis

Following a 4-week open-label run-in period, children and "young" adults (up to 40 years of age) with Marfan syndrome and a baseline echocardiogram were randomized to receive irbesartan (n = 104) or placebo (n = 88). The researchers excluded patients with prior or planned cardiac or aortic surgery or whose aortic root was greater than 4.5 cm; those who had severe valve disease, heart failure, some other therapeutic indication for an angiotensin receptor blocker; and women who were pregnant. Those randomized to the irbesartan group received 150 mg daily for the first 4 weeks, which was titrated to 300 mg daily if tolerated or if the patient weighed more than 50 kilograms. The researchers performed echocardiograms annually. After a median of 4 years of follow-up, 5 irbesartan-treated patients underwent aortic surgical procedures compared with 4 placebo-treated patients. Only one of the surgeries was for emergency treatment of aortic dissection (in that case the patient had received placebo). Overall, the rate of aortic dilation, either in absolute terms or adjusted for age and body size, was lower in the irbesartan-treated patients. Roughly 25% of patients in both groups reported at least one adverse effect of treatment.