Angina severity predicts worse sleep quality after coronary artery bypass grafting

We sought to reveal whether the severity of angina pectoris affects sleep quality after elective coronary artery bypass grafting.

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).

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).

The severity of angina pectoris in the preoperative period is independently associated with worse sleep quality after elective isolated coronary artery bypass surgery.