Background Aortic dissection is one of the most lethal potential complications in patients with the Marfan syndrome.Methods and Results Among 360 patients undergoing operative treatment of aortic dissection between 1963 and 1992, 40 had the Marfan syndrome.There were 24 men and 16 women with a mean age of 35+-9 years (+-1 SD; range, 15 to 54 years). These patients included 16 with acute type A, 2 with acute type B, 18 with chronic type A, and 4 with chronic type B aortic dissections. The aortic arch was involved in 29 cases. Preoperative complications included acute aortic valvular insufficiency in 13 patients, rupture into the pericardial space in 3, and loss of peripheral pulses in 9. The site of primary intimal tear was the ascending aorta in 25 patients, the aortic arch in 2, the descending aorta in 7, and not identified in 6. Operations included ascending aortic and aortic valvular replacement (with or without coronary artery reimplantation) in 22 patients, ascending aortic replacement alone in 5, and descending thoracic aortic replacement in 9. Four operative deaths (10+-5% (+-70% confidence limits)) occurred in 3 acute patient-years and 1 chronic type A patient-years. Long-term follow-up (216 patient-years; range, 1 month to 22 years; mean, 5.4 years) revealed 15 late deaths, 7 from late aortic sequelae. The overall actuarial survival estimates were 71+-8%, 54+-10%, and 22+-11% at 5, 10, and 15 years, respectively. Twenty late aortic operations were required in 14 patients.Conclusions Despite satisfactory early results, the long-term survival of patients with the Marfan syndrome was suboptimal (albeit similar to those without the Marfan syndrome). Future progress will pivot on reducing the incidence of aortic dissection in these patients with medical therapy and/or earlier surgical intervention and enhanced postoperative serial imaging surveillance of the entire aorta. (Circulation. 1994;90(part 2):II-235-II-242.)