Value of myocardial perfusion imaging in renal transplant evaluation

Abstract

Aim: Myocardial perfusion imaging (MPI) with SPECT (single photon emission computerized tomography) is commonly used for preoperative renal transplant assessment. We performed an audit to evaluate the prognostic value of MPI in this cohort. Method: Between 1999 and 2009, 838 transplants were performed in South Australia. A total of 387 patients had 393 preoperative MPI in three hospitals. Using a statewide electronic clinical information system (OACIS) cardiac events, MPI results (positive: any reversible defect; negative: fixed defects and normal), clinical follow up and comorbidities (diabetes and hypertension) were determined. End-point events were 'soft': admission with angina, percutaneous intervention or bypass; or 'hard': myocardial infarction or cardiac death. The end-point event rates were determined using Kaplan-Meier curves. Multivariate analyses were performed for age (60 years), gender, diabetes and hypertension. For negative MPI the event rates in dipyridamole stress were compared with tachycardic stress. Results: Soft events: There was a statistically significant lower event rate for MPI negative versus positive, 3.9% versus 20.8% (hazard ratio 4.4 confidence interval: 2.1-9.6, P < 0.001) at 5 years of follow up - no effect from age, gender, diabetes and hypertension. Hard events: There was a lower event rate for MPI negative versus positive (also unaffected by age, gender, hypertension and diabetes) but the result was not statistically significant, P = 0.153. For negative MPI the soft and hard event rates were similar for dipyridamole and tachycardic stress. Conclusion: MPI is a good modality of prognosticating cardiac events in renal failure patients being considered for transplantation. The value of a negative MPI is similar for dipyridamole and tachycardic stress.