Among 70 patients operated upon for acute dissection of the ascending aorta between 1977 and 1984, 14 (age range 40-72 years) benefited from emergency aortic arch repair motivated by the presence in, or extension to, this segment of the portal of entry, or by lesions of the supra-aortic main vessels. The operation was performed under cardiopulmonary bypass in all cases. Cerebral protection was ensured in 9 patients by deep hypothermia alone or with circulatory arrest for a mean period of 5 minutes (7 cases), and in 5 patients by continuous brain perfusion (carotid blood flow 4 ml/kg/min; perfusion pressure 70 mmHg). Repair consisted of ascending aorta replacement combined with gluing of the arch whenever possible, or bevelled resection in the concavity of the arch, or complete aortic arch replacement with reimplantation of the cervico-cerebral vessels when necessary. In every case the gelatin-resorcin-formalin glue was used to reinforce the aortic wall or the areas with sutures. Operative mortality was nil. Hospital mortality was 28.5%. In patients operated upon under deep hypothermia alone or associated with circulatory arrest the main complications were neurological (4 cases) and respiratory (3 cases) disorders; these were responsible for the death of 3 patients. A fourth patient died of mediastinitis. No neurological or respiratory complication occurred in patients who had brain perfusion. The mean follow-up period was 37 months (range 7-84 months). Late mortality was nil. All but one patient (sequelae of paraplegia) are in excellent clinical condition. Post-operative angiography alone or combined with computerized tomography showed satisfactory blood distribution in all cases and no aneurysm formation on the dissected aorta despite a persistent false lumen.