Usage of regadenoson in dynamic computed tomography perfusion (CTP) and magnetic resonance myocardial perfusion imaging (MR MPI) is off-label.The study aimed to assess the safety of regadenoson with theophylline reversal during CTP and MR MPI in patients with coronary artery disease (CAD).In this prospective study, patients with ≥1 intermediate coronary artery stenosis on computed tomography angiography, underwent CTP and MR MPI with 0.4 mg of regadenoson. After examinations, 200 mg of theophylline was given intravenously in 100 ml of saline. Changes in blood pressure (BP) and heart rate (HR) were repeatedly assessed. All side effects and adverse events were registered. From 112 examinations in 56 patients (25 females, 63.5 (8.5) years) all were diagnostic. There were no deaths, myocardial infarctions, severe arrythmia, high-grade atrio-ventricular block or bronchospasm. The most common symptoms were palpitations (17%), hot flushing (8%), chest discomfort (4%) and mild dyspnoea (3%). There were no significant differences between baseline and peak BP. There was a significant increase of peak HR after regadenoson as compared to the baseline (in MR MPI 63 [59-75] beats per minute (bpm) vs 93 [86-102] bpm, P < 0.001 and in CTP 65 [60-70] bpm vs 95 [86-107] bpm, P < 0.001). The haemodynamic response to the regadenoson and their side effect were completely reversible by theophylline.Regadenoson may be a safe vasodilator for CTP and MR MPI in CAD patients. Theophylline administration after perfusion examinations is safe and reverses regadenoson side effects.
