Postoperative complications after elective coronary artery bypass grafting surgery in patients with sleep-disordered breathing.

BACKGROUND: Sleep-disordered breathing (SDB) may increase the risk of postoperative complications in patients after cardiac surgery. This study evaluated the length of hospital stay as well as postoperative cardiac, respiratory, and renal complications after elective coronary artery bypass grafting (CABG) in patients without SDB, with central sleep apnea (CSA), or with obstructive sleep apnea (OSA). METHODS: The presence and type of SDB had been assessed with polygraphic recordings in 100 patients the night before elective CABG surgery. SDB was defined as an apnea-hypopnea index (AHI) of ≥ 15/h. Prolonged length of hospital stay (LOS) and postoperative hemodynamic instability due to any cause were retrospectively evaluated as primary endpoints and cardiac, respiratory, and renal complications as secondary endpoints. RESULTS: 37% of patients had SDB, 14% CSA, and 23% OSA. LOS differed significantly between patients without SDB and those with CSA and OSA [median (25;75. percentile): 8.0 days (7.5;11.0) vs. 9.5 days (7.0;12.5) vs. 12.0 days (9.0;17.0), Kruskal-Wallis test between three groups: p = 0.023; OSA vs. no SDB: p = 0.005]. AHI was significantly associated with prolonged LOS [> 9 days; odds ratio (OR) (95% confidence interval): 1.047 (1.001;1.095), p = 0.044]. Prolonged need of vasopressors (≥ 48 h) was observed in 36% of patients without SDB, in 64% with CSA, and in 62% with OSA (p = 0.037). AHI was significantly associated with prolonged (≥ 48 h) need of vasopressors [OR (95% CI): 1.052 (1.002;1.104), p = 0.040], independent of any confounders. CONCLUSIONS: SDB, particularly OSA, is associated with prolonged LOS after CABG, independent of known confounders. Prolonged LOS in patients with SDB may be due to increased postoperative hemodynamic instability due to any cause.

Sleep-disordered breathing is associated with disturbed cardiac repolarization in patients with a coronary artery bypass graft surgery.

BACKGROUND: The development of malignant ventricular arrhythmias due to abnormal cardiac repolarization is a major complication after coronary artery bypass graft surgery (CABG). Sleep-disordered breathing (SDB) is linked to prolonged cardiac repolarization in non-surgical patients. This study evaluates cardiac repolarization in patients with and without SDB who underwent CABG. METHODS: 100 patients who had received CABG (84% men, age 68 ± 10 years, body-mass-index [BMI] 28.7 ± 4.2 kg/m2) were retrospectively evaluated. Polygraphy was recorded the night before CABG. SDB was defined as an apnea-hypopnea index (AHI) of ≥15/h and differentiated into central (CSA) and obstructive (OSA) sleep apnea. Cardiac repolarization was assessed by means of T-peak-to-end (TpTe) and QTc-intervals and TpTe/QT-ratios derived from 12-lead electrocardiography (ECG). RESULTS: 37% of patients had SDB, 14% CSA and 23% OSA. Before CABG, patients with CSA and OSA had longer TpTe intervals than those without SDB (TpTe: CSA 100 ± 26 vs. OSA 97 ± 19 vs. no SDB 85 ± 14 ms, p = 0.013). QTc intervals and TpTe/QT ratios differed between the two groups (QTc: 444 ± 54 vs. 462 ± 36 vs. 421 ± 32 ms, p < 0.001; TpTe/QT ratio: 0.24 ± 0.04 vs. 0.23 ± 0.05 vs. 0.21 ± 0.03, p = 0.045). SDB was associated with abnormal cardiac repolarization independent of known risk factors for cardiac arrhythmias, such as age, sex, BMI, N-terminal-pro-brain-natriuretic-peptide (NT-proBNP), and heart failure (TpTe: B-coefficient [95%CI]: 16.0, [7.6-24.3], p < 0.001; QTc: 27.2 [9.3-45.1], p = 0.003; TpTe/QT ratio: 2.9 [1.2-4.6], p < 0.001). CONCLUSION: Independent of known risk factors for cardiac arrhythmias, SDB was significantly associated with abnormal cardiac repolarization before CABG. Data suggest that SDB may contribute to an increased risk of ventricular arrhythmias after CABG.