Since the first successful replacement of the aortic arch with perfusion of the head, various methods have been employed to preserve cerebral function during aneurysm operations. Although deep hypothermia was used for surgery of the aortic arch, as early as 1963, the introduction of prolonged circulatory arrest has simplified replacements of the aortic arch. Between October 1990 and September 1993, 69 patients underwent aortic arch replacement for aneurysmal disease at the Dept. of Cardio-Thoracic Surg., University of Vienna. 52 patients had an acute dissection Type A, 17 patients were operated on electively. The patients age (48 male, 21 female) ranged between 16 and 81 years. Primary diagnosis was hypertension (n=44), marfan (n=14), unknown (n=10) and trauma (n=1). Total cardiopulmonary bypass was established via femoral artery cannulation. All patients received Cortison and Thiopental for added cerebral protection. Deep hypothermia (12 degrees C), confirmed by 0-EEG, and circulatory arrest were induced in all patients. The aneurysm was opened longitudinally and a full thickness single patch or "island" of aortic wall, containing the origins of the three arch vessels, was constructed and anastomosed in a continuous fashion to an albumin coated graft. 68 patients survived the operation (intraoperative mortality 1%). The 30-day mortality was 23% (n=16). Twelve patients died of multiorgan failure, two patients of a stroke and two due to myocardial infarction. The mean cerebral circulatory arrest time was 32 minutes (range 11-61 min.). Our experience with aortic arch replacements using profound hypothermia and circulatory arrest supports our contention, that it is the method of choice in this very difficult surgical field.