Dissection in Marfan’s syndrome: the importance of descending aorta L. Mimoun, D. Detaint, F. Arnoult, G. Delorme, M. Gauthier, O. Milleron, C Meuleman, F. Raoux, A. Vahanian, G. Jondeau Consultation Marfan, Hôpital Bichat, Paris, France (2) Explorations fonctionnelles, Hôpital Bichat, Paris, France (3) Service de Cardiologie, Hôpital Bichat, Paris, France Objective: The purpose of our study was, in a large series of Marfan syndrome (MFS) patients surviving a first episode of aortic dissection to characterize patients with a first event on the descending aorta and the long term follow-up of surviving patients Methods and results: We included 100 adult MFS patients surviving a first aortic dissection on either the Ascending Aorta (AscAo) (n=37), the Descending Aorta (DescAo) (n=20) or both (As+DescAo n=43). Thus, descending aorta is frequently affected: 63% of our patients having presented a dissection Thirteen patients died during a follow-up of 7.3±5.5 years and 46 had an event, 70% of which involved the descending aorta. Events occurring during long term follow-up are mainly related to descending aorta. Prognosis was not depending on the location of the dissection, but on the fact that a dissected portion of the aorta remained after surgery. Among AscAo patients 5/23 incurred an event if all dissected aorta was removed vs. 11/14 patients in whom dissected aorta remained. Aortic dissection limited to the descending aorta, can occur in patients without dilatation of the ascending aorta. Among DescAo patients, diameter of the ascending aorta was below 50 mm in 12/20 patients and below 45mm in 11/20. Conclusion: Even when ascending aorta is not or moderately dilated, preventive measures (beta- blockers) are necessary in patients with MFS to prevent dissection of the descending aorta. Total removal of dissected aorta prevents delayed complications on the descending aorta.