Impact of integrating heart rate response with perfusion imaging on the prognostic value of regadenoson SPECT myocardial perfusion imaging in patients with end-stage renal disease

Background. We investigated whether integrating heart rate response (HRR) to regadenoson with myocardial perfusion imaging (MPI) analysis can enhance risk prediction in end-stage renal disease (ESRD) patients. Methods and Results. We prospectively followed 303 ESRD patients after regadenoson stress MPI for a mean of 35 months. Normal HRR to regadenoson was defined as >= 28% increase from baseline. Normal MPI was defined as a summed stress score <= 3 and left ventricular ejection fraction >= 50%. The study cohort was divided in four groups based on various combinations of normal/abnormal HRR and MPI. There was a step-wise increase in the risk of primary endpoint of all-cause death and the composite secondary endpoint of cardiac death or myocardial infarction; patients with Normal MPI/Normal HRR had the lowest event rates and those with Abnormal MPI/Abnormal HRR had the highest, whereas subjects with Abnormal MPI/Normal HRR and Normal MPI/Abnormal HRR had intermediate event rates. This pattern was maintained after adjusting for important clinical covariates. Conclusion. In ESRD patients, integrating HRR to vasodilator stress with MPI interpretation improves risk stratification. Normal HRR/Normal MPI identify truly low-risk group, whereas abnormal MPI or abnormal HRR portrays elevated risk.