Screening for carotid artery disease before cardiac surgery: Is current clinical practice evidence based?

Background: There is no clear consensus as to the correct screening procedu re to identify patients undergoing cardiac surgery and who are at greatest risk of stroke because of the presence of significant carotid artery stenos is. Such screening is important because some patients benefit from combined carotid and cardiac surgery and, regardless of this, the information gaine d puts the cardiac surgeon in a position to provide an accurate assessment of surgical risk. Our objective was to examine current clinical practice of carotid artery investigation prior to urgent cardiac surgery and to review this illustrative practice in the context of the world literature. Hypothesis: The study aimed to establish that current typical practice for screening cardiac surgical patients fur carotid artery disease is illogical according to the evidence in the world Literature. Methods: The study consisted of a retrospective assessment of all patients undergoing urgent cardiac surgery and a Medline-derived literature review, and included all patients undergoing urgent cardiac surgery at a tertiary c ardiothoracic center between January 1 and December 31, 1997. Results: Of 529 patients undergoing urgent cardiac surgery, 43 (8%) were sc reened preoperatively by duplex Doppler ultrasonography for carotid disease . The indications for screening were asymptomatic carotid bruit in 24 patie nts, history of stroke or transient ischemic attack (TIA) in 12 patients, a nd neither stroke, TIA, or bruit in 7 patients. The tests were requested ei ther by the attending cardiologists or by the cardiac surgeon to whom they were referred. One patient had already been diagnosed as having carotid art ery disease in the past. Thirteen patients underwent additional carotid inv estigations. Eleven patients were demonstrated to have internal carotid art ery stenosis greater than or equal to 60% and 3 patients underwent combined cardiac and carotid surgery. Review of the: literature revealed the follow ing groups to be at increased risk of future stroke unrelated to surgery, a nd of postoperative stroke: those with a history of stroke or TIA, those wi th carotid bruits, and, of importance, all patients with significant caroti d stenosis. Recent data suggest that symptomatic patients and the elderly a re at greatest risk. Conclusions: Only 8% of patients undergoing urgent cardiac surgery in a1I-y ear period were screened for carotid artery disease. We suggest that screen ing should definitely be performed in all patients with a history of stroke or TIA, all patients with a bruit, and all patients aged > 65 years. The l iterature suggests, however, that significant reductions in stroke rate cou ld be achieved by screening the whole cardiac surgical population, although there is a paucity of data that rue specifically pertinent to this patient subgroup. Further data are therefore required for the construction of a sc ientifically valid and medicolegally sound policy.