Heterogeneous aortic response to acute β-adrenergic blockade in Marfan syndrome

Although prophylactic treatment with β-blockers is used to retard aortic root dilatation in Marfan syndrome, it is not effective in all patients. To assess the effects of β-adrenergic blockade on the aorta's elastic properties, aortic stiffness index and distensibility were calculated in 13 patients with Marfan syndrome and 10 control subjects before and after β-adrenergic blockade. At baseline, patients with Marfan syndrome had a significantly increased stiffness index and decreased distensibility. After β-adrenergic blockade, 8 patients with Marfan syndrome developed stiffness indexes and distensibility values that were closer to normal, whereas these variables deteriorated in 5 patients. Thus the benefit of β-adrenergic blockade in Marfan syndrome may be the reduction in pulse pressure and myocardial contractility and also promotion of the elastic properties of the aorta. Moreover, the differential responses of aortic mechanics (normalizing or worsening) to β-adrenergic blockade may possibly have implications for the prognosis in these patients.