Fifty-two patients with Marfan syndrome and ascending aortic pathology were treated surgically between 1964 and 1990. The indication for primary operation was true aneurysm of the ascending aorta with or without aortic insufficiency in 35 patients (67%) and dissection in 17 (33%). Composite grafts were used in 28 patients (54%; group I) and other procedures on the ascending aorta in 24 patients (46%; group II). The latter included supracoronary graft replacement with or without aortic valve replacement or reconstruction (n = 13), and reconstruction of the ascending aorta with or without aortic valve replacement (n = 11). Composite graft insertion was combined with mitral valve surgery at the same operation in 3 patients (6%). The early mortality after primary operations was 7.7% (4 deaths) and the late mortality was 27% (14 deaths). Eight late deaths were related to cardiovascular complications. The mean follow-up was 6.7 years (range 1-27 years). The actuarial 5-, 10-, and 15-year survival rates for all patients were 82%, 63%, and 44%, respectively; for group I (composite grafts) they were 87%, 76%, and 57%; and for group II (other types of operations) they were 73%, 53%, and 37%. The incidence of late complications was much higher in group II than in group I (50% vs. 16%). At 5 and 10 years, the actuarial rates of freedom from late complications related to the primary operation were 88% and 80%, respectively, in group I and 65% and 18% in group II. Composite graft insertion is the operation of choice when approaching the ascending aorta and/or aortic valve in Marfan syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)