Regadenoson stress CMR: safety, feasibility and hemodynamic response

Abstract Background and objectives The use of regadenoson for stress cardiac magnetic resonance (CMR) has potential advantages over other vasodilators. We sought to evaluate the safety, feasibility and hemodynamic response (heart rate and blood pressure) of regadenoson in an unselected population undergoing stress CMR for clinical work-up. Methods A total of 603 regadenoson stress CMR clinical examinations performed between May 2017 and May 2020 in our institution were retrospectively reviewed. Studies were performed using a conventional stress/rest CMR protocol with a 1.5T MRI scanner. A fixed dose of 5 ml of regadenoson was employed as stressor. As part of the protocol, 200 mg of theophylline was administered between stress and rest acquisitions to reverse the vasodilator effect of regadenoson. Adverse events, clinical symptoms, and hemodynamic response were assessed. Results In our cohort, no severe adverse events requiring hospitalization were observed, and only 5 adverse events were reported (0.83%). Only two patients (0.3%) did not complete the test due to adverse events or symptoms related to regadenoson administration (one case presented severe hypotension; the other presented unbearable chest pain). There were no cases of bronchospasm, stress-induced arrhythmia or death. Over half of patients reported mild symptoms after drug administration (52%, n=314), more frequently dyspnea (19%, n=112), chest pain (18%, n=106) and flushing (6%, n=34). All symptoms resolved after theophylline administration. Overall, an increase in heart rate (mean increase and (standard deviation) = 24 (12.6) bpm and a mild decrease in systolic (−8.2 (17.1) mmHg) and diastolic (−4.9 (10.2) mmHg) blood pressure were observed as response to regadenoson. A blunted heart rate response was observed in elderly (p<0.01), diabetic (p<0.01) and obese (p=0.01) patients. Only 46 patients (7.8%) did not show tachycardization response. Conclusions The use of regadenoson in stress CMR proved to be safe and feasible in the vast majority of patients. Adverse events were not frequent with regadenoson and symptoms were transient and well tolerated, while premature ending of the test related to drug administration was very rare. Funding Acknowledgement Type of funding sources: None. Hemodynamic response