Abstract 17636: Safety and Tolerability of Regadenoson Stress CMR

Background & Objective: Regadenoson binds selectively to the A(2A) receptor to promote coronary vasodilation during stress testing. It is given as a fixed-dose rapid injection, thus simplifying the dosing regimen compared to adenosine and dipyridamole, obviating the need for an MRI compatible infusion pump. We assessed the safety and tolerability of regadenoson stress CMR. Materials & Methods: A group of 726 patients (age 57 ± 12, 56% males, 44% females, 20% diabetic (DM)) were prospectively recruited under an IRB-approved protocol with defined inclusion and exclusion criteria and scanned for clinical indications over a 30-month period. The control group consisted of 25 normal volunteers (age 23 ± 7). Patients were stressed with fixed dose regadenoson and scanned on a 1.5T scanner. Symptoms and major/minor adverse events including death, MI, arrhythmias, and hospitalization were assessed and recorded by the nurse and supervising physician. Results: Of the 726 exams, 99% (n=718) were of diagnostic quality. The most common symptoms in patients were dyspnea (30%, n=217), chest discomfort (28%, n=201), and headache (15%, n=111). Palpitations (60%, n=15) and dyspnea (28%, n=7) were common in the control group. Adverse events included bronchospasm (n=3, with one requiring hospitalization), symptomatic hypotension (n=1), contrast extravasation (n=2), and stress-induced SVT (n=1). Minor stress-induced arrhythmias (PVCs and PACs) occurred in 9% (n=67) of all exams. No VT/VF, death, MI, high grade AV block, or stress-induced atrial fibrillation occurred. There was no difference in SBP (p=0.60) and DBP (p=0.82) response, or rate pressure product (RPP) (p=0.33) between the patient vs. the control group. DM patients had a blunted heart rate (HR) response (p=0.002) when compared to non-DM patients despite a higher baseline HR (p=0.013), yet had no difference in SBP (p=0.30) and DBP (p=0.14) response, or RPP (p=0.20). Similarly, patients with abnormal perfusion exams had a blunted HR response (p=0.01), despite having a higher baseline HR (p Conclusions: Regadenoson CMR is well tolerated and can be performed safely with few adverse events. In diabetics and those with abnormal perfusion exams, a blunted HR response is noted.