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

BACKGROUND AND AIM OF THE STUDY

In order to achieve better operative results, myocardial protection for cardiac valve re-replacement must be further improved. The aim of this study was to compare the efficacy of continuous warm blood cardioplegia (CWBC) with that of intermittent cold potassium cardioplegia (ICPC) in cardiac valve re-replacement.

METHODS

A total of 49 consecutive patients underwent elective cardiac valve re-replacement via sternal re-entry; 27 patients received CWBC and 22 ICPC. During surgery, a narrower dissection of the heart was used in the CWBC group. The myocardial protective effects and operative outcome were analyzed 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 heart-beat after aortic declamping was significantly higher in CWBC patients than in the ICPC group (92.3% versus 13.6%, p < 0.001). Postoperatively, maximum serum creatine kinase-MB levels were significantly lower in CWBC patients 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 lactate (range: -0.02 to 0.14) in CWBC patients was maintained within the normal range immediately after aortic declamping and in the early postoperative period. In contrast, in ICPC patients extraction of myocardial oxygen (range: 0.18 to 0.23) and lactate (range: -0.27 to -0.17) was impaired during the same period. Postoperative (24-h) blood loss was significantly less in CWBC patients than in ICPC patients (p < 0.02).

CONCLUSION

In cardiac valve re-replacement surgery through sternal re-entry, and without wide exposure of the heart, continuous warm blood cardioplegia provides much greater myocardial protection than does intermittent cold potassium cardioplegia.