RIGHT-VENTRICULAR FUNCTION IN THE DONOR HEART

Objectives: Early morbidity and mortality post cardiac transplantation is frequently caused by right ventricular failure; this is usually at tributed to an elevated pulmonary vascular resistance in the recipient . Brain death in the donor is recognised as causing left ventricular d ysfunction, but its effects on the right ventricle have not previously been studied. The aim of this study was to investigate right ventricu lar function following brain death, using a canine model. Methods: The hearts of 33 dogs were instrumented with micromanometers, flow probes and dimension transducers to measure minor/major axes, and right and left ventricular free wall to septal distances. Left ventricular volum e was calculated according to the prolate ellipsoid model and right ve ntricular volume was calculated according to the shell subtraction met hod. Systolic function for left and right ventricles was analysed by p lotting ventricular stroke work vs. end-diastolic volume during a cava l occlusion (preload-independent recruitable stroke work PRSW). Brain death was instigated by inflation of a subdurally placed intracranial balloon; subsequently blood pressure was maintained with intravenous f luid whilst no inotropic medications were given. Data were collected a t baseline, and at 2 and 4 h thereafter. A two-tailed paired Student's t-test was applied to compare post-brain death data with baseline mea surements. Results: All animals had an initial hyperdynamic response p ost brain death ensued by the development of diabetes insipidus. Brain stem death was validated by neuropathological examination at the term ination of the experiments. Right and left ventricular systolic functi on had deteriorated significantly 2 h post brain death by 34.4% (+/- 5 .1%, P < 0.001) and 20.4% (+/- 3.4%, P < 0.001): respectively, from ba seline PRSW [RV = 23.6 erg.10(3) (+/- 1.5), LV = 76.2 erg.10(3) (+/- 3 .5)]. This deterioration remained at 4 h post 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 ca uses a significant decrease in left and right ventricular function. Th e injury to the right ventricle is more prominent than the left ventri cle, and at 2 h post brain death it is significantly greater. Failure of the right ventricle post transplantation in clinical practice may b e related to this brain death induced injury. Further studies are requ ired to investigate the mechanisms of this injury. (C) 1997 Elsevier S cience B.V.