OBJECTIVES: Fatal aortic dissection occurs at young age in Marfan syndrome. Prevention relies on elective replacement of the aortic root. The placement of an external aortic root support, tailored to the anatomy of the individual patient has been proposed as a feasible alternative. DESIGN, SETTING AND MAIN OUTCOME MEASURES: External aortic root support was offered to patients with Marfan syndrome with aortic root diameter of 40-55 mm and without aortic regurgitation. By computer-aided design, a model of the individual patient's aorta was created from cardiac magnetic resonance images and a bespoke external aortic support was manufactured. Comparative measurements were made of the ascending aorta at the level of closure of the aortic valve cusps from magnetic resonance imaging studies taken preoperatively, at first follow-up, and at most recent follow-up. For patients having aortic root surgery at the same institution, in the same time frame as the first 10 patients, clinical data were retrieved on Marfan and other patients having aortic root replacement to serve as a reference data. RESULTS: Twenty patients were operated upon from May 2004 to October 2009, 13 men and 7 women, median age 33 years. All 20 patients are alive and well at the time of last follow-up. Preoperative aortic diameters were 40-54 mm. All postoperative images were satisfactory with an overall reduction in aortic root dimensions. The surgery took half the time of other aortic root surgery. Cardiopulmonary bypass was used only in the first patient, myocardial ischemia was not required in any patient, and no postoperative anticoagulation is mandated. CONCLUSIONS: The primary objective of this surgery was fully achieved in 19 of the 20 patients, reinforcing the ascending aorta while leaving the native aortic valve intact and conserving the blood/endothelium interface.