Coronary surgery on the beating heart under extracorporeal circulation in high-risk patients. An acceptable compromise?

Coronary artery surgery with cardioplegia in high risk patients carries a risk of myocardial ischaemia and, without cardiopulmonary bypass, is not always technically feasible. The authors assessed an alternative, surgery on the beating heart with haemodynamic assist by cardiopulmonary bypass in 43 consecutive patients with poor left ventricular function (mean ejection fraction: 0.26), evolving myocardial ischaemia or acute myocardial infarction, old age (mean: 79.5 years) and comorbid conditions. Results were assessed mainly on clinical criteria. In addition, 9 patients had pre- and post-cardiopulmonary bypass measurements of markers of myocardial ischaemia (troponine Ic) and systemic inflammation (interleukines 6 and 10, elastase). In 6 cases, right atrial biopsy was analysed for expression of messenger ribonucleic acid coding for heat shock protein (HSP) 70; the data were compared with those of patients operated under warm blood cardioplegia. There was one cardiac death and one myocardial infarction. Myocardial conservation was confirmed by the minimal increase in troponine Ic levels and the significant increase in HSP 70 in RNA suggesting myocardial adaptation to stress. On the other hand, the minimal concentrations of mediators of inflammation were not significantly changed. In selected high risk patients, coronary revascularisation on the beating heart under cardiopulmonary bypass could be a valuable alternative. It conserves the potentially deleterious effects of cardiopulmonary bypass but peroperative global myocardial ischaemia, an important factor in the aggressivity of cardiac surgery, is eliminated.