Preload-recruitable stroke work relationships and diastolic dysfunction in the brain-dead organ donor.

Background: Acute graft failure is an important cause of morbidity and mortality in cardiac transplantation, and it may be associated with myocardial changes that occur during brain death (BD). This study investigates the changes in biventricular systolic and diastolic function that occur after BD in a validated canine model.

Results: The hearts of 20 mongrel canines (23 to 31 kg) were instrumented with micromanometers, flow probes, and dimension transducers to measure minor/major axes as well as left and right ventricular (LV/RV) septum-to-free wall distances. LV/RV volumes were measured according to the shell subtraction method. LV/RV systolic function was analyzed by ventricular stroke work plotted versus end-diastolic volume during a caval occlusion (preload-independent recruitable systolic work, PRSW). The nonlinear relationships between diastatic pressure (stress) and LV/RV septum-to-free wall distances and volumes (strain) from successive diastoles during caval occlusion were used to evaluate LV/RV diastolic mechanics. The Cushing phenomenon, hyperdynamic response, and diabetes insipidus were observed in each animal after BD. Results are expressed as mean +/- SEM (P < .05 versus baseline, ANOVA, paired two-tailed Student's t test). Biventricular systolic function deteriorated significantly from baseline PRSW 6 to 7 hours after BD. The diastatic LV/RV pressure dimension relationships were significantly different after BD, indicating a decrease in ventricular chamber compliance during diastole.

Conclusions: BD causes a significant loss of systolic and diastolic LV/RV function in the brain-dead, heart-beating cadaver, which may contribute to early postoperative cardiac graft failure in the recipient. These findings have significant clinical applications and may help to avoid suboptimal donor/recipient matches.