Cardiac reanimation for donor heart transplantation after cardiocirculatory death

Abstract

Background: This study was conducted in donor hearts obtained after cardiocirculatory death (DCD) to determine whether pre-reperfusion cardioplegia, followed by warm blood perfusion, is superior to cold storage in preserving function sufficient for transplantation.

Methods: Greyhound dogs (n = 15) were anesthetized and cardiocirculatory death and circulatory failure was induced by cessation of mechanical ventilation. After 30-minutes, the hearts were preserved by perfusion or were infused with modified St. Thomas' cardioplegia, explanted, and stored for 4 hour at 4 degrees C. Perfusion hearts were briefly reperfused with an acidic, mitochondrial protective cardioplegic solution and then continuously perfused for 4 hours with normothermic blood. Hearts from a normal reference group (no cardiocirculatory arrest) were preserved by St. Thomas' cardioplegia and cold storage. In all groups, 40 minutes of room temperature ischemia was used to simulate the conditions of transplantation. Final functional and metabolic assessments were made on a working heart apparatus.

Results: Perfusion hearts (n = 6), when compared with cold storage hearts (n = 6), produced a greater rate of change in left ventricular pressure (1121 +/- 273 vs 336 +/- 193 mm Hg/sec, p = 0.04), greater echocardiographic fractional area reduction (71.3% +/- 10.0% vs 25.4% +/- 2.9% of baseline, p = 0.004) and lower perfusate lactate levels (1.5 +/- 1.4 vs 9.7 +/- 1.4 mmol/liter; p = 0.002). Functional recovery in perfusion hearts was comparable to the normal hearts (n = 3).

Conclusion: For DCD hearts, a strategy of pre-reperfusion cardioplegia, followed by continuous warm blood perfusion, is superior to cold storage. These results suggest DCD hearts may be more suitable for transplantation after continuous warm blood perfusion than after cold storage.