Monitoring of perfusion quality and prediction of donor heart function during ex-vivo machine perfusion by myocardial microcirculation versus surrogate parameters

ABSTRACT Currently, lactate (Lac) is used to evaluate machine perfusion (MP) of hearts, donated after circulatory death (DCD). We hypothesize that monitoring of myocardial microcirculation (mLDP) by Laser-Doppler-Perfusion is superior to Lac to evaluate perfusion and predict contractility. In a pig model, DCD-hearts were perfused four hours followed by reperfusion and left ventricular contractility measurement. Lac and mLDP were measured every 30 min in successfully (N=9) and unsuccessfully (N=7) maintained hearts. Successfully maintained hearts showed decreasing Lac (5.6 to 2.8 mmol/L) and slightly downregulated (92%) mLDP. In unsuccessfully maintained hearts Lac first decreased (5.1 to 3.8 mmol/L) followed by increase and mLDP dropped to 39%. In a single-variable regression only mLDP showed a significant r² for systolic (0.514, p=0.045) and diastolic (0.501, p=0.049) parameters. The combination of mLDP and Lac (r2=0.876, p=0.005) showed best results. mLDP seems to be superior to Lac to show perfusion disorders and predict DCD-heart contractility.