Background: The use of regadenoson in dynamic computed tomography perfusion (CTP) and magnetic resonance myocardial perfusion imaging (MR MPI) is off‑label.

Aims: The study aimed to assess the safety of regadenoson with theophylline reversal during CTP and MR MPI in patients with coronary artery disease (CAD).

Methods: In this prospective study, patients with 1 or more intermediate coronary artery stenoses 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 recorded.

Results: Out of 106 examinations in 53 patients (25 females, 63.5 [8.5] years), all were diagnostic. There were no deaths, myocardial infarctions, severe arrhythmias, high‑grade atrioventricular blocks, or bronchospasms. The most common symptoms were palpitations (17%), hot flushing (8%), chest discomfort (4%), and mild dyspnea (3%). There were no differences between baseline and peak BP. There was an increase in median (interquartile range) peak HR after regadenoson as compared with baseline (MR MPI, 63 [59–75] bpm vs 93 [86–102] bpm; P < 0.001; and CTP, 65 [60–70] bpm vs 95 [86–107] bpm; P < 0.001). The hemodynamic response to regadenoson and its side effects were completely reversible by theophylline.

Conclusions: Regadenoson may be a safe vasodilator for CTP and MR MPI in patients with CAD. The administration of theophylline after perfusion is safe and reverses side effects of regadenoson.