• normalised aortic diameter at the level of the sinus of valsalva [ Time Frame: every six months ] [ Designated as safety issue: Yes ]
  

• cardiac surgery, hospitalisation in cardiology ward, death [ Time Frame: during the follow up ] [ Designated as safety issue: Yes ]
  

Aim : evaluate the efficacy of losartan for limiting aortic dilatation in patients with marfan syndrome receiving standard therapy

Inclusion criteria :

10 years or older Marfan syndrome according to international criteria Signed informed consent

Non inclusion :

Previous surgery of the ascending aorta, or surgery planned Non echogenicity Contre-indication lactose Pregnancy on going or planned within 3 years Breast feeding Participation in another clinical study Non member of the social security or CMU

Number of subjects : the number of subjects (150 per group) is derived from the study from Shores et al (1994) demonstrating the benefit of beta-blockade in Marfan patient and uses a decrease by half of the aortic dilatation with losartan

Follow-up is 3 years, after inclusion period of 2 years. A total of 5 years is expected

Methods : randomised double blind vs placebo study. All French centres de competence for marfan syndrome and the centre de reference are participating in the study.

End points : main endpoint is evolution of normalised aortic diameter. Secondary endpoints include clinical events (cardiac surgery or aortic dissection, hospitalisation in cardiology department, death), tolerance of the drug, and quality of life.