Cold Crystalloid Perfusion Provides Cardiac Preservation Superior to Cold Storage for Donation After Circulatory Death

Background. We previously showed that donation after circulatory death (DCD) canine hearts can be resuscitated if perfused with warm blood. However, clinical application of this technique is complex and difficult. We have developed a simplified system of cold crystalloid perfusion and compared it with standard cold storage for DCD heart preservation. Methods. Anesthetized greyhounds underwent 30 minutes DCD by withdrawal of ventilation followed by assignment to either 4 hours of perfusion (n = 6) or cold storage (n = 7). Nonpreserved hearts (n = 5) served as a normal reference group. Perfusion hearts were reperfused with a protective solution then perfused for 4 hours with a novel oxygenated, nutrient-containing solution at 20 mL/min at 4 degrees C to 10 degrees C. Cold storage hearts were flushed with St Thomas' cardioplegic solution and stored in ice. After preservation, the recovery of the hearts was assessed on a blood-perfused working heart rig. Results. During preservation, perfusion hearts consumed oxygen (0.09 +/- 0.01 mL/100 g per minute) and showed decreasing lactate production in the perfusate (initial: 0.031 +/- 0.004 vs final: 0.007 +/- 0.002 mmol/min; P = 0.001). After preservation, compared to cold storage hearts, perfusion hearts had higher cardiac output (P = 0.004), LV dP/dt max (P = 0.003) and myocardial oxygen efficiency (P = 0.01), with lower blood perfusate lactate (P = 0.007). Hemodynamic values of perfused hearts reached 60% or more those in the normal reference group. Conclusions. Continuous cold crystalloid perfusion in a canine model of DCD: (1) facilitates aerobic metabolism and resuscitates the DCD heart, (2) provides functional and metabolic recovery superior to cold storage, (3) shows promise for improved clinical preservation of DCD and marginal donor hearts.