The Effect of Mean Arterial Pressure During Cardiopulmonary Bypass on the Post-Operative Outcomes in Coronary Artery Bypass Graft Surgery

Cardiopulmonary Bypass MAP in CABG

Abstract

ABSTRACT

Background: Maintenance of an optimal mean arterial pressure (MAP) is vital for cerebral blood flow and the overall health of the patients undergoing coronary artery bypass graft (CABG). 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 convenient sample of 55 patients with low MAP (55 mm Hg) and 54 patients with MAP (75 mm Hg) who underwent CABG at Tehran Heart Center in 2023. We recorded the patients' demographic and clinical characteristics of patients by measuring cerebral oximeter reading and lactate levels pre- and post-operation. We then compared the baseline and postoperative characteristics between the two 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 (55 mm Hg) group (P=0.016). The preoperative and postoperative measurements (including lactate levels and cerebral oximeter reading) did not differ between the two groups. However, the heart rate was significantly higher in the MAP (75 mm Hg) group (P=0.034). The adjusted effect of baseline MAP on selected postoperative characteristics showed that it can significantly but inversely influence heart rate (beta coefficient=-5.952; P=0.017) and has a borderline effect on troponin (beta coefficient=1.734; P=0.051) and HCO3 (beta coefficient= 0.785; P=0.062).

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