Myocardial Protection and Hemodynamic Effects During Beating Heart Coronary Artery Bypass Grafting with Parallel Cardiopulmonary Bypass in High-Risk Cardiac Surgery Patients

Objective: To evaluate the cardioprotective potential and hemodynamic impact of beating-heart coronary artery bypass grafting (CABG) performed with parallel cardiopulmonary bypass in patients with reduced left ventricular ejection fraction (LVEF).

Materials and Methods: A single-center prospective randomized controlled blinded trial included 90 patients with LVEF <35% who underwent CABG surgery. The patients were divided into two groups. In the first group (n=60), surgery was performed under cardiopulmonary bypass with cardioplegia (CP). Patients in the second group (n=30) underwent surgery on a beating heart with parallel CPB (pCPB). The primary endpoint was the concentration of troponin I on the first postoperative day (POD). Secondary endpoints included hemodynamic parameters, vasoactive-inotropic score (VIS), markers of myocardial injury (CK, CK-MB) and heart failure (BNP, NTproBNP); postoperative complications, 30-day mortality, and long-term survival.

Results: Troponin I levels on the first POD were not significantly different between the groups, with values of 3.61 (2.32-7.51) ng/ml in the CP group and 5.25 (2.41-10.89) ng/ml in the pCPB group, р=0.327. Preoperative cardiac index was significantly higher in the pCPB group compared to the CP group (p=0.036); however, no statistically significant differences were observed at subsequent stages of the study. Mean pulmonary artery pressure, pulmonary capillary wedge pressure, mean arterial pressure also did not differ significantly between the groups. The postoperative period was similar between the two groups in terms of complications. The 30-day mortality was 1.7% (1/60) in the CP group and 6.7% (2/30) in the pCPB group (p = 0.257). Within one year after randomization, mortality was 3.3% (2 patients) in the CP group and 23% (7 patients) in the pCPB group (HR 7.5, 95% CI 1.6-36, p=0.012).

Conclusions: Beating-heart CABG with parallel CPB in high-risk patients does not provide a cardioprotective effect and does not reduce troponin I levels. The use of this technique in patients with reduced LVEF does not affect cardiac index, the need for inotropic/vasopressor support, the incidence of complications or in-hospital mortality, but it is associated with poorer long-term patient survival at 1 year.

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