Coronary oxygen persufflation for long-term myocardial protection.

In human heart transplantation limited myocardial ischemia duration remains one of the most restricting factors. A new approach towards prolongation of this duration is the combination of cardioplegic arrest and continuous Coronary Oxygen Persufflation (COP) with gaseous oxygen. This technique, which is based on former experiments, was applied in pig hearts which we transplanted orthotopically after a hypothermic preservation time of 14 hours. For cardioplegic arrest we used either Euro-Flush glutathion solution (EFG; n=5), University of Wisconsin solution (UW; n=5), modified Bretschneider HTK cardioplegic solution (mHTK; n=6). In preliminary experiments all three solutions had shown equal cardioprotective qualities. Hearts of the mHTK group were submitted to continuous COP during storage (mHTK+COP). After 14 hours of preservation and orthotopic transplantation the mHTK+COP hearts showed significantly improved cardiac functional recovery compared to hearts preserved by simple cold storage techniques. Hemodynamics measured after 3 hours reperfusion were significantly better in the mHTK+COP group compared to EFG and UW: dp/dtmax in % of baseline+/-standard deviation (SD): 85+/-22, 65+/-26, 36+/-15, CO in % of baseline: 68+/-13, 35+/-8, 39+/-8. Postoperative preload recruitable stroke work in the mHTK+COP hearts was: 51.4+/-23.1 mmHg compared to preoperative: 57.3+/-17.2. ATP of left-ventricular myocardium in the mHTK+COP group: 14.7+2.1 micromol/g dry weight was significantly higher compared to EFG: 10.3+/-4.5 and UW: 5.9+/-3.2. CK-MB in percent of CK in all groups showed no increase during postoperative reperfusion. This study suggests that COP may present an effective complement to cold storage techniques currently used in heart transplantation. Prior to clinical application further investigations regarding long-term survival and endothelial function are required.