12: Cardiac storage with a perfusion device prevents tissue lactate accumulation

Abstract

Purpose: Continuous perfusion devices may improve ischemic tolerance and extend preservation times. Initial clinical trials of these devices will likely involve standard preservation intervals. This study examined the effects of continuous perfusion in a large animal heart transplant model over a clinically relevant storage time. Methods and Materials: Hearts in adult dogs were instrumented with sonomicrometry crystals and a left ventricular (LV) micromanometer and LV function was quantified by the preload-recruitable stroke work (PRSW) relationship. Hearts were arrested with Celsior solution supplemented with 5 mM glucose, removed, and randomized to (A) storage in this solution in an ice chest (n 6) or (B) continuous perfusion with an identical solution at 10ml/100g/min in a perfusion device (n 6). After 4 h storage, samples of left atrium were frozen and later analyzed by magnetic resonance spectroscopy. Hearts were transplanted into recipient dogs and reperfused for 6 h, and function was measured. After 6 h, LV water content and serum CK-MB levels were measured. Results: LV function was similar at baseline in both the perfused and static-stored organs (PRSW: 50.4 5.9 vs 51.0 1.9 mmHg, mean SEM, respectively; p 0.64) and remained similar after 6 h reperfusion (40.4 6.4 vs 39.6 10.8 mmHg; p 0.62). Serum CK-MB levels after 6 h of reperfusion were similar (4.0 1.1 vs 6.9 2.4 ng/ml, p 0.30) in the perfused and static preserved organs. LV water content was not increased in the perfusion preservation group compared to routine storage (78.3 0.5% vs 78.3 0.2%; p 1.0). However, tissue collected at end-storage had significantly higher lactate content in the static storage group (expressed as lactate:alanine ratio; 0.6 0.4 vs 4.0 0.5; p 0.01). Conclusions: Continuous perfusion of donor hearts nearly eliminates tissue lactate accumulation without increasing myocardial edema. This may imply maintenance of oxidative metabolism or washout of anaerobic by-products during storage. Perfusion preservation may have advantages for heart preservation even over short storage intervals. I have received research support from Organ Transport Systems, the manufacturer of the perfusion device used in these studies; Organ Transport Systems, Inc.