Surgical treatment of aneurysm or dissection involving the ascending aorta and aortic arch, utilizing circulatory arrest and retrograde cerebral perfusion. Recently we replaced the ascending aorta and aortic arch in 8 patients with aneurysm or dissection, using profound hypothermic circulatory arrest with retrograde cerebral perfusion. There were no operative deaths. Open aortic anastomosis facilitated repair of the aortic arch without clamping the arch tributaries, and embolism due to particulate debris from clamping of the arch vessels was eliminated. Retrograde cerebral perfusion during profound hypothermic circulatory arrest is a simplified technique that may protect the brain. This method offers advantages over previously described methods, particularly in obviating dissection of the arch tributaries and the clamping thereof, and in protecting the central nervous system. 