Enhanced Cardiac Preservation with Oxygenated University of Wisconsin Solution

Abstract

The purpose of this study was to determine if oxygen delivery to rabbit cardiac allografts arrested and stored in University of Wisconsin solution (UWS) at 4°C would affect preservation. Nineteen isolated rabbit hearts were rapidly excised and perfused at 80 mm Hg on an isovolumic modified Langendorff apparatus. A micromanometer was placed within a balloon and inserted into the left ventricle through the mitral valve orifice. Digitized pressure waveforms were collected at 11 known balloon volumes froth 0.8 to 1.2 ml. Baseline data were obtained for all hearts while perfused with Krebs-Henseleit solution equilibrated with 95% O2:5% CO2 at 37°C. All hearts were arrested with 30 ml of UWS (290 mOsm). The control group (N = 10) was stored in UWS at 4°C for 8 hr, and the experimental group (N = 9) was perfused with oxygenated UWS (O2 content = 5.6 ml O2) at 4°C for 8 hr at a pressure of 60 mm Hg (5-10 ml/min). Both groups were then reperfused with Krebs-Henseleit buffer at 80 mm Hg for 15 min at for postpreservation data acquisition. Left ventricular developed pressures over a physiologic range (pressure-volume area) and maximum positive and negative dP/dt were calculated. Recovery of left ventricular parameters as a percentage of the baseline values was determined. Mean pressure-volume area recovery in the nonperfused group was 40 ± 7.9% versus the perfused group (71 ± 7.0%, P = 0.01). Mean maximum negative dP/dt recovery in the nonperfused group was 44 ± 8.5% versus the perfused group (69 ± 7.3%, P = 0.046). Mean maximum positive dP/dt recovery in the nonperfused group was 40 ± 7.6% versus the perfused group (76 ± 8.7%, P = 0.005). The analysis of these parameters demonstrates between 25 and 36% improvement in recovery of left ventricular performance after infusing rabbit hearts with oxygenated UWS during 8 hr of storage versus storage alone. Perfusion of rabbit myocardium with oxygensted UWS provides better cardiac protection over 8 hr versus storage alone in UWS at 4°C.