Can technetium 99m pyrophosphate be used to quantify myocardial injury in donor hearts?

Background. There are no prospective methods available to quantify the myocyte injury in hearts prior to transplantation. The potential of the isotope labeled infarct marker 99m Technetium pyrophosphate (TcPPT) being used in this role was investigated. Methods. Brain death was induced by creating an extradural space occupying lesion in young adult swine after which hemodynamic changes were monitored and myocyte injury was quantified by histochemistry. TcPPT was administered 5 hours after induction of intracranial hypertension, and after hearts were harvested myocardial uptake was measured. These latter measurements were related to the histochemical assessment of myocyte injury. Results. Sham animals (n = 4) maintained cardiovascular stability and experienced minimal myocyte injury, grades 0 to 3. BD animals (n = 10) exhibited varying patterns of hemodynamic change and myocyte injury, the latter was significant in 6, graded 4 to 11, p less than 0.05. Uptake of TcPPT by BD hearts was greater than twice the 90th centile sham value in 6. The sensitivity and specificity of greater uptake indicating the presence of myocyte injury was 83.3% and 75% respectively. Conclusions. TcPPT has the potential to quantify myocardial injury induced by brain death and its potential utility merits further investigation.