Effect of induction and reperfusion with warm substrate-enriched cardioplegia on ventricular function

Background. This study tested the hypothesis that induction and reperfusion with warm substrate-enriched (IRWSE) blood cardioplegia improves postoperative left ventricular (LV) function in patients undergoing elective coronary bypass surgery (CABG). Methods. After giving informed consent, 67 patients scheduled for CABG surgery were randomized to either IRWSE + cold blood (CB) or CB alone. IRWSE cardioplegia consisted of 37°C substrate-enriched (glutamate, aspartate, hyperkalemic) anterograde and retrograde blood cardioplegic solution followed by non-substrate-enriched cardioplegic solution given at 4°C to 8°C. LV function was measured with ventriculograms, volume conductance catheters, echocardiography, and multiple gated (image) acquisition. Results. The end-systolic pressure-volume relationship was improved postbypass in the IRWSE + CB group (CB, 1.5 ± 0.74 mm Hg/mL vs IRWSE + CB, 2.1 ± 1.2 mm Hg/mL; p = 0.042). The postoperative ejection fraction (EF%) was better preserved in the CB group (CB, 65 ± 11.53% vs IRWSE + CB, 58.62 ± 11.75%; p< 0.04). Conclusions. Our results demonstrate a transient improvement in LV systolic function in the immediate postbypass period in CABG patients in the IRWSE + CB group. The intraoperative benefits of the IRWSE + CB technique did not persist in the postoperative period.