Comparison of different techniques of hypothermic pig heart preservation.

The aim of this study was to compare several methods of hypothermic heart preservation. Isolated pig hearts were preserved for 24 hours in cold cardioplegic solution (St. Thomas' Hospital modified solution) by continuous perfusion (group I), microperfusion (group II), or simple storage (group III). The findings were then compared with those from hearts harvested and immediately reperfused (the control group). Group III hearts showed lower adenosine triphosphate preservation (0.47 +/- 0.18 mumol/g) than did group I and II hearts and the control hearts (1.86 +/- 0.40, 1.98 +/- 0.27, and 1.84 +/- 0.55 mumol/kg, respectively). Electronic microscopy studies also revealed that the myocardial cells in the group III hearts appeared to be damaged. After the hearts had undergone preservation, myocardial function was studied for 60 minutes under nonworking conditions using an ex vivo functional testing system. For group III, the mean left ventricular developed pressure and ventricular compliance (16 +/- 22 and 63 +/- 48 mm Hg, respectively) differed significantly from those for group I (83 +/- 26 and 0 +/- 0 mm Hg, respectively), group II (83 +/- 33 and 14 +/- 18 mm Hg, respectively), and the control group (115 +/- 13 and 0 +/- 0 mm Hg, respectively). We concluded from our findings that perfusion methods are superior to cold storage but inadequate to maintain heart viability for the long term during hypothermia. These techniques must be improved before they can be adopted for clinical use.