Prognostic value of heart rate response during regadenoson stress myocardial perfusion imaging in patients with end stage renal disease.

BACKGROUND: Blunted heart rate response (HRR) to vasodilator stress agents is associated with worse outcomes. There are limited data assessing the effect of impaired HRR to regadenoson among patients with end-stage renal disease (ESRD) undergoing stress myocardial perfusion imaging (MPI).

METHODS: We prospectively followed patients with ESRD enrolled in the ASSUAGE and ASSUAGE-CKD trials. HRR was defined as 100*(peak stress heart rate-resting heart rate)/resting heart rate. Study cohort was dichotomized to blunted and normal HRR groups according to an established median HRR value <28% or ≥28%, which were propensity-score matched based on 22 clinical and imaging covariates. The Primary endpoint was all-cause death. The secondary cardiac-specific endpoints included: (1) the composite endpoint of cardiac death or myocardial infarction; (2) the composite endpoint of cardiac death, myocardial infarction, or late (>90 days) coronary revascularization.

RESULTS: There were 303 patients followed for 35 ± 10 months. In the entire cohort, there was a stepwise increase in the rates of death and all secondary endpoints with worsening HRR (P values ≤.001). Blunted HRR (<28%) was associated with increased risk of death (unadjusted hazard ratio 4.10 [1.98-8.46], P < .001) and all secondary endpoints (P ≤ .001). After multivariate adjustment, HRR remained an independent predictor of mortality and secondary endpoints whether used as continuous or dichotomous variable, and added incremental prognostic value for all-cause death (P = .046). Blunted HRR was associated with increased event rate among patients with normal myocardial perfusion (P = .001) and abnormal perfusion (P = .053). In the propensity-matched cohort of 132 patients (66 in each group), blunted HRR was associated with significant increase in all-cause death (21% vs. 5%, HR 5.09 [1.46-17.7], P=.011), and similarly for the secondary endpoints.

CONCLUSION: Blunted HRR (<28%) to regadenoson is a strong and independent predictor of death and cardiovascular events in patients with ESRD and adds incremental prognostic value.