The Impact of Mean Arterial Pressure during Cardiopulmonary Bypass on Postoperative Outcomes in Coronary Artery Bypass Graft Surgery

Afzal Shamsi; Senan Salim Alaroofa; Mehdi Dehghani Firoozabadi; Dena A. Alkazzaz; Behrang Nooralishahi; Mohammadjavad Mehrabanian

doi:10.18502/jthc.v19i2.16198

Afzal Shamsi Department of Anesthesia, School of Allied Medical Sciences, Tehran University of Medical Sciences, Tehran, Iran.
Senan Salim Alaroofa Department of Anesthesia, School of Allied Medical Sciences, Tehran University of Medical Sciences, Tehran, Iran.
Mehdi Dehghani Firoozabadi Department of Anesthesiology, Tehran Heart Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
Dena A. Alkazzaz Division of Anesthesia, Department of Surgery, College of Medicine, University of Mosul, Mosul, Iraq.
Behrang Nooralishahi Nursing and Midwifery Care Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Mohammadjavad Mehrabanian Department of Anesthesiology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.

DOI: https://doi.org/10.18502/jthc.v19i2.16198

Keywords: Coronary artery bypass graft; Mean arterial pressure; Lactates; Oximetry

Abstract

Background: Maintaining an optimal mean arterial pressure (MAP) is vital for cerebral blood flow and the overall health of patients undergoing coronary artery bypass graft (CABG) surgery. This study investigated the impact of low MAP on cerebral blood flow and in-hospital clinical outcomes in CABG candidates at our hospital.

Methods: We compared a convenience sample of 55 patients with a low MAP (55 mmHg) and 54 patients with a high MAP (75 mmHg) who underwent CABG at Tehran Heart Center in 2023. We recorded the patients' demographic and clinical characteristics by measuring cerebral oximeter readings and lactate levels pre- and post-operation. We then compared the baseline and postoperative characteristics between the 2 groups and determined the impact of MAP on their postoperative changes.

Results: The groups were statistically similar at baseline, except for a lower pH in the low MAP group (55 mmHg) (P=0.016). The preoperative and postoperative measurements (including lactate levels and cerebral oximeter readings) did not differ between the groups. However, heart rate was significantly higher in the high MAP group (75 mmHg) (P=0.034). The adjusted effect of baseline MAP on selected postoperative characteristics showed that it could significantly but inversely influence heart rate (β coefficient=-5.952; P=0.017) and had a borderline effect on troponin (β coefficient=1.734; P=0.051) and HCO₃ (β coefficient=0.785; P=0.062).

Conclusion: MAP did not significantly influence clinical outcomes in our study. Nonetheless, maintaining an optimal MAP is essential for preventing cerebral injury and ensuring adequate cerebral oxygenation in CABG patients.