Risk factors for stroke after coronary artery bypass grafting.

BACKGROUND

Stroke is a feared complication after coronary artery bypass grafting surgery (CABG), with an incidence between 1.3 and 4.3%.

OBJECTIVE

To identify predictive factors for stroke after CABG in the modern era of cardiac surgery.

METHODS

This is a case-control study of 65 pairs of patients, paired by sex, age (+ 3 years) and date of CABG (+ 3 months). The cases were patients submitted to elective CABG with extracorporeal circulation (ECC) that presented stroke (defined as clinical neurological deficit up to 24 hours post-operatively and confirmed by imaging assessment) and the controls were those individuals submitted to elective CABG with ECC, but without stroke.

RESULTS

The univariate analysis demonstrated that the number of revascularized vessels was associated with the occurrence of stroke after the CABG (3 +/- 0.8 vs. 2.76 +/- 0.8, p = 0.01). The multivariate analysis by conditional logistic regression showed that systemic arterial hypertension (SAH) [OR: 6.1 (1.5 - 24), p = 0.009] and diabetes mellitus (DM) [OR: 3.1 (1.09 - 11), p= 0.03] were the determinants of the highest chance of stroke after CABG, whereas acute myocardial infarction (AMI) > 1 month, was the determinant of the lowest chance of stroke [OR: 0.1 (0.03 - 0.36), p = 0.003].

CONCLUSION

Hypertension and diabetes mellitus were identified as independent predictors of stroke within the first 24 postoperative hours after CABG. In patients with such risk factors, it is possible that the knowledge of the causal mechanisms of brain injury represents a strategy capable of decreasing the incidence of stroke after CABG.