Effectiveness of continuous warm blood cardioplegia in cardiac valve re-replacement

Background ann aim of the study: In order to achieve better operative resul ts, myocardial protection for cardiac valve re-replacement must be further improved. The aim of this study was to compare the efficacy of continuous w arm blood cardioplegia (CWBC) with that of intermittent cold potassium card ioplegia (ICPC) in cardiac valve re-replacement. Methods: A total of 49 consecutive patients underwent elective cardiac valv e re-replacement via sternal re-entry; 27 patients received CWBC and 22 ICP C. During surgery, a narrower dissection of the heart was used in the CWBC group. The myocardial protective effects and operative outcome were analyze d in the two groups. Results: Two ICPC patients died in hospital, one from cerebral bleeding and one from low output syndrome. The rate of spontaneous recovery of the hear tbeat after aortic declamping was significantly higher in CWBC patients tha n in the ICPC group (92.3% versus 13.6%, p < 0.001). Postoperatively, maxim um serum creatine kinase-MB levels were significantly lower in CWBC patient s than in ICPC patients (25.5 +/- 6.0 versus 81.1 +/- 26.0 IU/l, p < 0.02). Left ventricular stroke work index in the CWBC group showed significantly better recovery in the early postoperative period compared with that in the ICPC group. Extraction of myocardial oxygen (range: 0.33 to 0.35) and lact ate (range: -0.02 to 0.14) in CWBC patients was maintained within the norma l range immediately after aortic declamping and in the early postoperative period. In contrast, in ICPC patients extraction of myocardial oxygen (rang e: 0.18 to 0.23) and lactate (range: -0.27 to -0.17) was impaired during th e same period. Postoperative (24-h) blood loss was significantly less in CW BC patients than in ICPC patients (p < 0.02). Conclusion: In cardiac valve re-replacement surgery through sternal re-entr y, and without wide exposure of the heart, continuous warm blood cardiopleg ia provides much greater myocardial protection than does intermittent cold potassium cardioplegia.