Background: Vasodilator nuclear stress testing is frequently ordered for risk stratification prior to kidney transplantation. Since 82Rb-positron emission tomography-computed tomography can measure myocardial blood flow (MBF), the response to vasodilator stress can be verified rendering the results of the scan more reliable.
Methods: We reviewed the MBF response to dipyridamole infusion in 328 patients with end-stage kidney disease (ESKD) prior to transplant (188 hemodialysis-HD, 120 peritoneal dialysis-PD, and 20 pre-dialysis patients-CKD5) and in 100 controls with normal kidney function. A stress/rest MBF ratio ≥ 2 was considered an adequate response to dipyridamole. Coronary artery calcium (CAC) was measured on CT.
Results: Inadequate MBF response was seen in 36%-HD, 21%-PD, 45%-CKD5 vs. 23%-controls (p = 0.006). Univariable predictors of poor MBF response in ESKD patients were age, diabetes mellitus, and CAC (all p < 0.03) while serum hemoglobin was borderline significant (p = 0.052). Multivariable predictors of a poor MBF response were age (p = 0.002) and lower serum hemoglobin (p = 0.014). Ischemia was identified in 8% of ESKD patients and 24% of controls (p < 0.001).
Conclusions: ESKD patients are less likely to respond appropriately to vasodilator stress compared to patients with normal renal function and had a lower incidence of ischemia despite a high pre-test probability of disease. Physicians performing vasodilator stress without MBF measurement should be aware of the high probability of a false negative response.
Keywords: Hemodialysis; Kidney transplantation; Myocardial blood flow; Positron emission tomography; Risk stratification.