HETEROGENEOUS AORTIC RESPONSE TO ACUTE BETA-ADRENERGIC-BLOCKADE IN MARFAN-SYNDROME

Although prophylactic treatment with beta-blockers is used to retard a ortic root dilatation in Marfan syndrome, it is not effective in all p atients. To assess the effects of beta-adrenergic blockade on the aort a's elastic properties, aortic stiffness index and distensibility were calculated in 13 patients with Marfan syndrome and 10 control subject s before and after beta-adrenergic blockade. At baseline, patients wit h Marfan syndrome had a significantly increased stiffness index and de creased distensibility. After beta-adrenergic blockade, 8 patients wit h Marfan syndrome developed stiffness indexes and distensibility value s that were closer to normal, whereas these variables deteriorated in 5 patients. Thus the benefit of beta-adrenergic blockade in Marfan syn drome may be the reduction in pulse pressure and myocardial contractil ity and also promotion of the elastic properties of the aorta. Moreove r, the differential responses of aortic mechanics (normalizing or wors ening) to beta-adrenergic blockade may possibly have implications for the prognosis in these patients.