OBJECTIVE The surgical management of patients with aortic valve disease associated with ascending aortic dilatation is a controversial issue. Structural abnormalities of the aortic wall predispose to further aortic enlargement and possibly to ascending aortic dissection (AAD). Indications to concomitant replacement of aortic valve and ascending aorta have not yet been clearly defined. METHODS We reviewed eight consecutive patients (seven males and one female) among 2202 patients who underwent aortic valve replacement (AVR) between 1982 and 1996. These eight were subsequently reoperated on because of AAD, between November 1987 and November 1996. Indications for initial AVR were aortic regurgitation due to annular ectasia in five patients, combined aortic stenosis and regurgitation in two, and isolated aortic stenosis in one patient. RESULTS The interval between AVR and AAD ranged from four months to 10.5 years. Five patients presented with acute AAD, and three with chronic AAD. Retrospectively, four patients showed progressive increase in ascending aortic diameter after AVR, with a mean diameter of 72+/-9 mm at reoperation. Histological examination showed cystic medial necrosis in three patients, atherosclerotic degeneration in one patient, and normal aortic wall structure in one. There was one operative death due to low cardiac output; the hospital mortality rate was 13%. There were no late deaths and no major adverse events during a mean follow up of 5+/-3 years (range: 8 months to 10 years). CONCLUSIONS In patients with ascending aortic dilatation (> or = 55 mm diameter), AVR alone may not prevent progression of aortic root enlargement. In these patients, the ascending aorta should be concomitantly replaced. Following AVR, all patients with mildly or moderately dilated aortic root should be periodically controlled to detect signs of progression of aortic dilatation.