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Published on: March 27, 2018
Cardio-autonomic functions and sleep indices before and after coronary artery bypass surgery
Khamis Mohammed Al-Hashmi1, Mohammed A Al-Abri2, Deepali S Jaju2
1Department of Physiology, College of Medicine and Health Sciences, Sultan Qaboos University, Al Khoud, Muscat, Sultanate of Oman.
Insights
Coronary artery bypass grafting (CABG) surgery showed early recovery of cardio-autonomic functions within 30 days. This study found no significant short-term impact of CABG on obstructive sleep apnea (OSA) indices in patients with ischemic heart disease.
Area of Science:
- Cardiology
- Sleep Medicine
- Autonomic Neuroscience
Background:
- Coronary artery bypass grafting (CABG) may impair cardio-autonomic function short-term.
- Recovery timelines post-CABG vary, with limited data on obstructive sleep apnea (OSA) influence.
- Objective sleep assessment is often lacking in studies linking post-CABG atrial fibrillation to OSA.
Purpose of the Study:
- To assess the impact of CABG on cardio-autonomic, hemodynamic, and OSA indices in patients with ischemic heart disease (IHD).
- To determine the recovery trajectory of these functions post-CABG.
Main Methods:
- Evaluated 26 stable IHD patients undergoing CABG.
- Measured heart rate variability (HRV) indices, hemodynamic parameters, and sleep study data preoperatively, on day 6, and day 30 post-CABG.
Main Results:
- High-frequency HRV powers significantly increased by day 6 post-CABG (P=0.002), indicating improved parasympathetic activity.
- Low-frequency HRV powers significantly decreased by day 6 (P=0.002), suggesting reduced sympathetic activity.
- No significant changes were observed in baroreceptor sensitivity, OSA indices, or oxygen saturation levels at any assessment point.
Conclusions:
- Autonomic function recovery post-CABG can occur as early as 30 days.
- CABG does not appear to significantly affect sleep study indices in the short term.
- Long-term effects of CABG on these parameters require further investigation.
Background:
Earlier studies showed a short-term impairment of cardio-autonomic functions following coronary artery bypass grafting (CABG). There is a lack of consistency in the time of recovery from this impairment. Studies have attributed the post-CABG atrial fibrillation to preexisting obstructive sleep apnea (OSA) without an objective sleep assessment. The aim of this study was to evaluate the effect of CABG on cardio-autonomic and hemodynamic functions and on OSA indices in patients with ischemic heart disease (IHD).
Methods:
Cardio-autonomic function using heart rate variability indices, hemodynamic parameters, and sleep studies were performed in 26 patients with stable IHD before, on day-6, and day-30 post-CABG surgery.
Results:
The high-frequency powers of normalized R-R intervals significantly (P = 0.002) increased from the preoperative value of 46.09 to 66.52 on day-6 and remained unchanged on day-30 postsurgery. In contrary, the low-frequency powers of normalized R-R interval decreased from 53.91 to 33.48 during the same period (P = 0.002) and remained unchanged on day 30 postsurgery. Baroreceptor sensitivity, obstructive and central apnea indices, desaturation index, and lowest O2 saturation were not significantly different between preoperative, day-6, and day-30 postsurgery.
Conclusion:
Our study revealed that recovery of autonomic functions following CABG occurs as early as 30 days of postsurgery. CABG does not seem to have short-term effects on sleep study indices. However, long-term effects need further evaluation.
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