Dr. Tunick''s major research interest has been the investigation of causes of stroke and peripheral embolization, particularly those involving atherosclerotic disease of the thoracic aorta. In 1990 he described the first stroke patients with a new finding on transesophageal echocardiography: protruding atheromas in the aortic arch (1).

He then performed a case-control study of 244 patients (122 age- and sex-matched pairs) which showed that there was a strong association between protruding atheromas and embolic disease (2). The significance of these findings is underlined by the fact that these atheromas are found in approximately 25% of patients referred because of unexplained stroke, TIAs or peripheral emboli, and thus constitute an important new etiology for these diseases.

A prospective study followed, which showed that the risk of future spontaneous embolization from protruding aortic atheromas is approximately 33% during a follow-up period averaging only 14 months (3).

The group of patients undergoing surgery with cardiopulmonary bypass is at especially high risk, as cannulation of the aorta may result in the dislodging of atherosclerotic material and thrombi from the aortic arch. A prospective study in the operating room showed that these atheromas are an important cause of stroke due to cannulation of the aortic arch during heart surgery (4). A subsequent study of 268 patients with aortic arch atheromas (5) showed a very high risk of intraoperative stroke (approximately 12%, or 6 times higher than the average intraoperative stroke rate during cardiac surgery). This study also showed that arch endarterctomy, designed to try to prevent stroke, actually increases the risk.

Most recently, Dr. Tunick completed a retrospective study of treatment in 519 patients with severe aortic arch plaque. Those treated with statins had significantly fewer strokes and other embolic events than those on antiplatelet drugs (aspirin etc.) or those on anticoagulation (coumadin). It appears that statins may stabilize aortic plaques (as they do coronary artery plaques) and prevent embolic events.