Prospective clinical and biological comparison of three blood cardioplegia techniques in low-risk CABG patients: better is worse than good enough

Abstract

Objective: Three myocardial protection techniques were evaluated in a prospective, randomised trial during coronary artery bypass grafts in 69 patients.

Material and method: Twenty seven patients received intermittent hyperkalaemic undiluted warm blood anterograde cardioplegia (AC), 21 received continuous hyperkalaemic undiluted warm blood retrograde cardioplegia (RC) and 21 received intermittent, hyperkalaemic, diluted cold blood (15 °C), anterograde cardioplegia (CC). Assessment criteria were clinical, laboratory and haemodynamic.

Results: Groups were homogeneous in terms of age, sex, cardiovascular risk factors, severity of coronary disease, preoperative ejection fraction, and number of bypass grafts performed. The oxygen extraction coefficient, and lactate and troponin production in the coronary sinus on aortic unclamping was not significantly different between the three groups. The base excess was −0.19±0.13 in the RC group, −0.18±0.52 in the AC group and −2.67±0.59 in the CC group (P<0.01 CC vs. AC and CC vs. RC). The priming volume was 1485±64 ml (CC), 1317±44 ml (RC) and 1318±30 ml (AC) (P<0.05 CC vs. AC and CC vs. RC). The haematocrit during CPB was 28.9±0.9 (CC), 32.5±0.8 (RC) and 32±0.7 (AC) (P<0.05 CC vs. AC and CC vs. RC). The volume of crystalloid delivered was 735±85 ml (CC), 362±67 ml (RC) and 357±105 ml (AC) (P<0.05 CC vs. AC and CC vs. RC). The incidence of ventricular fibrillation on aortic unclamping was 61.9% (CC), 9.5% (RC) and 0% (AC) (P<0.01 CC vs. AC and CC vs. RC). The transfusion rate, duration of intubation, postoperative troponin level, complication rate and mortality were not significantly different between the three groups. Haemodynamic parameters at H2, H4, H8 did not vary significantly between the three groups.

Conclusion: These three techniques appear to be comparable in terms of myocardial protection. Anterograde cardioplegia ensures an identical degree of security to retrograde cardioplegia regardless of the coronary lesions, apart from redo lesions. CC requires greater haemodilution of the patients during CPB.