PERFLUOROCHEMICAL REPERFUSION YIELDS IMPROVED MYOCARDIAL RECOVERY AFTER GLOBAL-ISCHEMIA

Reperfusion injury remains a limiting factor in extending ischemic sto rage time for human heart transplantation. In this study, initial myoc ardial reperfusion with an oxygenated perfluorochemical (Fluosol) was investigated as a means of limiting such injury. Neonatal piglet heart s were arrested with crystalloid cardioplegia, excised, and stored for 12 hours in saline solution at 0-degrees-C. Initial reperfusion (10 m inutes) was either with whole blood (n = 6), unmodified perfluorochemi cal (n = 8), or aspartate/glutamate-enriched perfluorochemical cardiop legia (n = 6), and was followed by an additional 40 minutes of whole b lood perfusion. Functional evaluation was then completed, and left ven tricular biopsy specimens were taken. A control group (n = 7) was eval uated without an intervening period of ischemia. At a left ventricular end-diastolic pressure of 9 mm Hg, hearts stored in whole blood cardi oplegia developed a left-ventricular stroke work index of 3.8 +/- 2.3 x 10(3) erg/g (mean +/- standard error of the mean). Under the same co nditions, perfluorochemical-reperfused hearts achieved a stroke work i ndex of 14.6 +/- 1.3 x 10(3) erg/g, significantly greater than that of the whole blood group (p < 0.001). Stroke work index for hearts reper fused with aspartate/glutamate-enriched perfluorochemical cardioplegia was 19.8 +/- 1.6 x 10(3) erg/g, significantly increased over that of the nonenriched perfluorochemical group (p < 0.01) and not different f rom values obtained in controls (19.2 +/- 0.8 x 10(3) erg/g). In addit ion, perfluorochemical-reperfused hearts demonstrated superior mainten ance (p < 0.05) of adenosine triphosphate (2.08 +/- 0.16 mumol/g) comp ared with the whole blood group (1.50 +/- 0.19 mumol/g), whereas prese rvation of adenosine triphosphate in the enriched perfluorochemical gr oup (2.99 +/- 0.12 mumol/g) was significantly increased over that of t he nonenriched perfluorochemical group (p < 0.001 mumol/g) and not sig nificantly different from that in controls (2.68 +/- 0.17 mumol/g). El ectron microscopy revealed notably improved preservation of ultrastruc tural architecture in perfluorochemical-treated hearts (with or withou t aspartate/glutamate) compared with the whole blood group. We conclud e that initial reperfusion of the postischemic myocardium with oxygena ted perfluorochemical ameliorates the deleterious effects of whole blo od reperfusion. In addition, amino acid enrichment, buffer supplementa tion, and chemical cardioplegia enhance this effect, allowing for comp lete functional recovery of the piglet myocardium after 12 hours of hy pothermic ischemia.