Right ventricular function in the donor heart

Abstract

OBJECTIVES: Early morbidity and mortality post cardiac transplantationis frequently caused by right ventricular failure; this is usuallyattributed to an elevated pulmonary vascular resistance in the recipient.Brain death in the donor is recognised as causing left ventriculardysfunction, but its effects on the right ventricle have not previouslybeen studied. The aim of this study was to investigate right ventricularfunction following brain death, using a canine model. METHODS: The heartsof 33 dogs were instrumented with micromanometers, flow probes anddimension transducers to measure minor/major axes, and right and leftventricular free wall to septal distances. Left ventricular volume wascalculated according to the prolate ellipsoid model and right ventricularvolume was calculated according to the shell subtraction method. Systolicfunction for left and right ventricles was analysed by plotting ventricularstroke work vs. end- diastolic volume during a caval occlusion(preload-independent recruitable stroke work PRSW). Brain death wasinstigated by inflation of a subdurally placed intracranial balloon;subsequently blood pressure was maintained with intravenous fluid whilst noinotropic medications were given. Data were collected at baseline, and at 2and 4 h thereafter. A two-tailed paired Student's t-test was applied tocompare post-brain death data with baseline measurements. RESULTS: Allanimals had an initial hyperdynamic response post brain death ensued by thedevelopment of diabetes insipidus. Brain stem death was validated byneuropathological examination at the termination of the experiments. Rightand left ventricular systolic function had deteriorated significantly 2 hpost brain death by 34.4% (+/- 5.1%, P < 0.001) and 20.4% (+/- 3.4%, P< 0.001), respectively, from baseline PRSW [RV = 23.6 erg.10(3) (+/-1.5), LV = 76.2 erg.10(3) (+/- 3.5)]. This deterioration remained at 4 hpost brain death (29.4% (+/- 4.9%, P < 0.001) and 21.2% (+/- 4.3%, P< 0.001), respectively). (The results are expressed as mean and S.E.M.).CONCLUSIONS: Brain death causes a significant decrease in left and rightventricular function. The injury to the right ventricle is more prominentthan the left ventricle, and at 2 h post brain death it is significantlygreater. Failure of the right ventricle post transplantation in clinicalpractice may be related to this brain death induced injury. Further studiesare required to investigate the mechanisms of this injury.