Independent Predictors of Stroke in OPCAB Population

Objective: Stroke is very devastating complication after coronary artery bypass grafting. According to literature it appears in up to 4% of the patients after isolated coronary artery bypass surgery. The purpose of this study was to identify risk factors for perioperative stroke.

Method: We analyzed retrospectively the prospective collected data of 2626 consecutive patients who underwent isolated off pump coronary artery bypass grafting surgery from January 1, 2003, till December 31, 2015, in our institution without aortic clamping, using HeartString device. Primary end point was incidence of stroke during hospitalization. We identified 11 variables found in literature as predictive for stroke: age over 75, female gender, severely impaired ejection fraction (EF < 35%), arterial hypertension, peripheral vascular disease, previous history of stroke, smoking history, renal insufficiency, urgent surgery, conversion to CPB and high EuroScore (ES > 6). The univariate and multivariate logistic regression analysis were performed.

Results: Overall in hospital mortality was 1,4%. 20 patients from 2626 suffered stroke (0.8%). Four of them died, resulting in a mortality rate of 20%. 13 patients suffered hemiplegia with or without dysarthria, showing the symptoms directly after operation. Five patients suffered visual disturbances such as diplopia, hemianopsia, or even complete blindness (one patient), which appears rather later on the ward. All patients with stroke had a structural brain damage in computed tomography. The univariate logistic regression analysis showed significantly higher risk for stroke according to gender, renal impairment and conversion to cardiopulmonary bypass. The multivariate logistic regression analysis revealed two variables as independent predictors of stroke: female gender and conversion to cardiopulmonary bypass.

Conclusion: Avoiding aortic side clamping in OPCAB reduces neurologic complications substantially. Nevertheless mortality rate in patients suffering stroke postoperatively remains extremely high. The independent predictors for stroke in OPCAB avoiding aortic side clamping are female gender and conversion to cardiopulmonary bypass. On the other side age over 75 years, history of stroke or even the incidence of peripheral vascular disease as well as high EuroScore and severely impaired ejection fraction does not influence the occurrence of stroke in OPCAB.