In patients suffering from aortic dissection, persistent perfusion of the false lumen distal to the implanted graft is frequent. Postoperative follow-up examinations of the carotid arteries of these patients were performed by duplex scanner and correlated with clinical symptoms. Thirty-nine patients who survived the surgical treatment of acute type A aortic dissection had duplex sonography of both common carotid arteries after an average postoperative follow-up of 53 months. In 21 cases a composite graft and in 18 cases a supracoronary prosthetic vascular graft were implanted. No sign of residual dissection of the common carotid arteries was seen in 23 patients; in nine there was a dissection of both common carotid arteries, and seven patients had a unilateral carotid dissection (five right, two left). There were nine symptomatic patients with the following symptoms: transient ischemic attack (four), amaurosis fugax (four), stroke with incomplete recovery (one). Two symptomatic patients had a corresponding dissection. The generally good prognosis of all these patients suggests a conservative nonoperative treatment.