PROGRESSION OF AORTIC DILATATION AND THE BENEFIT OF LONG-TERM BETA-ADRENERGIC-BLOCKADE IN MARFANS-SYNDROME

Background. The aortic root enlarges progressively in Marfan's syndrom e, and this enlargement is associated with aortic regurgitation and di ssection. Longterm treatment with beta-adrenergic blockade, by reducin g the impulse (i.e., the rate of pressure change in the aortic root) o f left ventricular ejection and the heart rate, may protect the aortic root. Methods. We conducted an open-label, randomized trial of propra nolol in adolescent and adult patients with classic Marfan's syndrome (32 treated and 38 untreated [control] patients). Aortic-root dimensio ns and clinical end points (aortic regurgitation, aortic dissection, c ardiovascular surgery, congestive heart failure, and death) were monit ored for an average of 9.3 years in the control group and 10.7 years i n the treatment group. All 70 patients were included in the analysis a ccording to the intention-to-treat principle. Results. The dose of pro pranolol was individualized; the mean (+/-SE) dose was 212+/-68 mg per day. The mean slope of the regression line for the aortic-root dimens ions, which reflect the rate of dilatation, was significantly lower in the treatment group than in the control group (0.023 vs. 0.084 per ye ar, P<0.001). Clinical end points were reached in five patients in the treatment group and nine in the control group. The Kaplan-Meier survi val curve for the treatment group differed significantly from that for the control group during the middle years of the trial and remained b etter for the treatment group throughout the study. Conclusions. Proph ylactic beta-adrenergic blockade is effective in slowing the rate of a ortic dilatation and reducing the development of aortic complications in some patients with Marfan's syndrome.