Prognostic impact of SPECT-MPI after renal transplantation

Background — While renal transplantation is increasingly performed for end-stage renal disease, there is a paucity of data on cardiac screening and prognostication post-transplant. We determined the prognostic value of SPECT-MPI in a cohort who underwent renal transplantation.

Methods — Among 4933 renal transplant recipients identified from the Canadian Organ Replacement Register, we examined outcomes of patients who underwent SPECT-MPI in Ontario, Canada. We determined morbidity and mortality using hospitalization and vital statistics registries, according to SPECT-MPI findings.

Results — We studied 282 renal transplant recipients (median age 46 years [25th, 75th percentile 37, 58]) with detailed SPECT-MPI results available, followed for a median of 5.7 (3.3, 7.7) years. Among those undergoing SPECT-MPI (66% pharmacologic stress), 41% had an abnormal summed stress score (SSS > 0) and 31% demonstrated abnormal summed difference score (SDS > 0). Rates of cardiovascular death were 0.4 per 100 person-years among those with normal stress perfusion (SSS = 0) and 0.4 per 100 person-years with SDS = 0. After adjusting for age, sex, prior myocardial infarction (MI), and cardiac risk factors, an SSS ≥ 4 conferred increased risk of cardiovascular death or cardiovascular hospitalization with adjusted hazard ratios of 2.52 (95% CI 1.41, 4.52, P = .002) for SSS 4-6 and 2.61 (95% CI 1.52, 4.49, P < .001) for SSS ≥ 7. SDS was a significant predictor of cardiovascular death or hospitalization, with adjusted hazard ratios of 2.96 (95% CI 1.72, 5.09, P < .001) for SDS 4-6 and 3.26 (95% CI 1.64, 6.50, P < .001) for SDS ≥ 7.

Conclusion — Among renal transplant recipients, SPECT-MPI predicted risk of cardiovascular death and cardiovascular hospitalization events.