Angina severity predicts worse sleep quality after coronary artery bypass grafting

Objective: We sought to reveal whether the severity of angina pectoris affects sleep quality after elective coronary artery bypass grafting. Material and methods: Patients scheduled to undergo isolated coronary artery bypass grafting were divided into two groups, having a recent myocardial infarction (Group 1, n=22, mean age 59.40±7.79 years) or not having a recent myocardial infarction (Group 2, n=30, mean age 59.73±7.72 years). The assessment included the Canadian Cardiovascular Society Angina Score, the visual analogue scale for postoperative pain and the Pittsburgh Sleep Quality Index (PSQI). Results: The two groups were similar in regard to baseline characteristics. Cross-clamp time was significantly higher (p=0.007) and the use of inotropes was significantly more common (p=0.01) in those patients with recent myocardial infarction compared to those without. Mean Canadian Cardiovascular Society scores were also higher in patients with recent myocardial infarction (p=0.02). Total Pittsburgh Sleep Quality Index score was significantly higher in patients with recent myocardial infarction (8.45±3.50 vs. 5.03±2.32, respectively, p<0.001). In multivariate analysis, higher angina score (OR: 3.27, 95% CI, 1.20-8.90, p=0.02) and longer time of intensive care unit stay (OR: 6.15, 95% CI, 1.49-25.35, p=0.01) were found to be independent predictors of poor sleep quality. The Canadian Cardiovascular Society angina score showed a significant positive correlation with poor sleep duration score (<0.001), sleep disturbance score (p=0.02), day dysfunction due to sleepiness score (p=0.001), sleep efficiency score (p=0.003), overall sleep quality score (0.03) and total PSQI score (p=0.004). Conclusion: The severity of angina pectoris in the preoperative period is independently associated with worse sleep quality after elective isolated coronary artery bypass surgery.