Abstract T MP56: Immediate Post-operative Serum Blood Urea Nitrogen is Strongly Associated with Early Post-surgical Stroke Risk in Cardiac Surgical Patients
Objective: To identify perioperative risk factors that are associated with post-operative stroke risk after all cardiac surgical procedures at a large tertiary hospital.
Methods: Among 5498 adults aged 18-90 years who underwent cardiac surgery at Johns Hopkins Hospital from 2005-2010, we identified 180 cases who suffered a stroke within 10 days post-operatively. An equal number of controls were randomly selected and frequency-matched for sex and age-band to cases. Univariate and multivariate logistic regression analyses were performed to ascertain risk factors for post-operative stroke.
Results: Emergent surgery (OR 3.04, 95% CI 1.80- 5.10), current smoking (OR 1.97, 95% CI 1.29- 3.00), peripheral vascular disease (OR 2.80, 95% CI 1.41-5.53), and previous stroke with residual paralysis (OR 4.27 95% CI 1.18-15.38) were associated with increased stroke risk. Pre-operative blood pressures were higher in cases than in controls (p <0.0001). Log of immediate post-operative BUN was higher in cases than in controls (p< 0.0001). In multivariable logistic regression (adjusted for pre-operative hematocrit, post-operative creatinine, acute myocardial infarction and low ejection fraction), post-operative BUN was associated with increased odds of stroke (OR 2.4 per 25% increase in BUN, p <0.0001). Postoperative stroke risk was also predicted by emergent surgical status (OR=2.7, p=0.014), current smoking (OR= 2.8, p=0.002) and pre-operative diastolic blood pressure (OR: 1.8 for every 10-point increase in DBP, p<0.0001). ROC curves indicated that post-operative BUN (AUC = 0.855) largely explained the increased post-operative stroke risk. AUC for the adjusted final model was 0.896 and the ROC curve that excluded post-operative BUN only yielded an AUC of 0.700.
Conclusion: In these analyses we have identified factors that are associated with post-operative stroke for all types of cardiac surgery. Awareness of these exposures may improve stroke risk assessment.
Author Disclosures: M.K. Arnan: None. T. Hsieh: None. J. Yeboah: None. A. Bertoni: None. G. Burke: None. Z. Bahrainwala: None. M. Grega: None. W. Baumgartner: None. R. Gottesman: None.
- © 2015 by American Heart Association, Inc.