ISCHEMIC STROKE AFTER SURGICAL-PROCEDURES - CLINICAL-FEATURES, NEUROIMAGING, AND RISK-FACTORS

Objective: To describe risk factors and explore mechanisms of ischemic strokes after general surgery. Background: Strokes follow general sur gery in about 0.08% to 2.9% of cases. Patients with previous cerebrova scular disease, atrial fibrillation, hypertension, advanced age, or at herosclerosis were found to have an increased risk. Knowledge of facto rs involved may guide physicians in determining the overall risk of su rgery, Methods: This case-control study was performed in a referral ce nter. A total of 61 patients identified through a computerized databas e with ischemic strokes after surgical procedures-excluding heart, bra in, vessels, or neck-between July 1986 and July 1996 were studied. Pro cedures included 11 urogenital, 16 gastrointestinal, 17 orthopedic, 12 pulmonary, and 5 other. A total of 122 randomly selected controls wer e matched for age, sex, procedure, and year of procedure. Main outcome measures included arterial territory, timing, risk factors, and perio perative events. Differences were expressed as adjusted odds ratios (A OR) with 95% confidence limits (CL), using multivariate conditional lo gistic analyses for matched case-control design. Results: Arterial ter ritory included 37 middle cerebral artery, 11 posterior circulation, 7 borderzone, and 6 multiple. Median procedure to stroke interval was 2 days (range, 0 to 16); 10 patients had intraoperative strokes. Three major risk factors emerged: previous cerebrovascular disease (AOR 12.5 7, 95% CL 2.14/73.70), chronic obstructive pulmonary disease (COPD) (7 .51, 1.87/30.12), and peripheral vascular disease (PVD) (5.35, 1.25/22 .94). After adding stroke-related factors, PVD (14.70, 2.01/107.71) an d COPD (10.04, 1.90/53.14) remained the strongest variables; blood pre ssure (1.05, 1.01/1.10) and urea (1.04, 1.01/1.07) contributed slightl y. Hypotension did not contribute. Four patients (6.6%) and no control s had diffuse intravascular coagulation(p = 0.01). Four stroke patient s had myocardial infarction (6.6% versus 0%; p = 0.01). Conclusions: I schemic strokes after general surgery most commonly occur after an asy mptomatic interval. Previous cerebrovascular disease, COPD, and PVD gr eatly increase the risk. Hypotension rarely accounts for postoperative strokes. Major comorbidity of the patient at risk seems more importan t than complicating events during surgery.