Myocardial flow reserve in chronic kidney disease and renal transplantation: A cross-sectional study of ammonia PET

Abstract Objective Renal transplantation (RT)’s effects on coronary artery and microvascular diseases is not yet elucidated. We aimed to quantify myocardial blood flow (MBF) using 13N-ammonia positron emission tomography (NH3-PET) and compare the results between RT recipients and patients with chronic kidney disease (CKD).Methods Adenosine-stress NH3-PET measurements of 29 RT recipients and 564 patients with CKD were assessed. Stress and rest MBF were calculated from the dynamic data of the initial 2 min after the ammonia injection. Myocardial flow reserve (MFR) was defined as stress MBF divided by rest MBF; MFR < 2.0 or stress MBF < 2.0 ml/g/min was considered a significant decrease.Results Stress MBF for RT recipients and patients with end-stage and mild-stage CKD was 2.03 ± 0.60, 1.72 ± 0.62, and 2.07 ± 0.61 ml/g/min, respectively; their MFRs were 2.00 ± 0.60, 1.68 ± 0.51, and 2.26 ± 0.69, respectively. Stress MBF and MFR were significantly greater in RT recipients than in patients with end-stage CKD (P < 0.01). The MFR was significantly greater in patients with mild-stage CKD than in RT recipients (p < 0.05); however, there was no significant difference in stress MBF. The proportion of patients with MFR ≥ 2.0 or stress MBF ≥ 2.0 ml/g/min was significantly higher in RT recipients than in patients with end-stage CKD (51.7% vs. 26.3%, and 58.6% vs. 26.3%, p < 0.01).Conclusion RT may improve MFR in patients with end-stage CKD by acting on adenosine vasodilation.