Over a 7-month period, 15 consecutive patients underwent resection and reconstruction of the transverse aortic arch for a variety of pathologic lesions using moderate systemic hypothermia (24 degrees C) and brief circulatory arrest. Simplified surgical techniques were developed to allow rapid repair. The "open" aortic technique facilitated repair of arch aneurysms, aortic dissections and obstructive lesions of the arch tributaries. The mean cerebral ischemic time was 11.2 +/- 1.5 minutes (mean +/- SEM). Moderate hypothermia afforded adequate cerebral and myocardial protection during circulatory arrest and shortened the duration of extracorporeal bypass necessary for the cooling and rewarming phases (87 +/- 8 minutes). Dacron grafts preclotted by a new method greatly reduced postoperative blood loss. Since these simplified techniques were adopted, 14 patients (93%) have survived aortic arch replacement, with minimal postoperative morbidity. One patients with severe preoperative left ventricular dysfunction died of cardiac failure after operation. These results suggest that aortic arch replacement can be performed safely and with low operative risk.