Safety and tolerability of pharmacologic stress with the selective A2A adenosine receptor agonist regadenoson for the assessment of myocardial ischemia: results from 5780 consecutive patients in a cardiology practice.

OBJECTIVES

This study investigated the safety and tolerability of regadenoson for pharmacologic stress testing in the context of myocardial scintigraphy under routine clinical conditions in a cardiology practice in 5780 consecutive patients.

BACKGROUND

The drug regadenoson was approved in Germany in 2010 for pharmacological stress testing in myocardial scintigraphy for patients who are unable to undergo adequate physical exercise. Previously, only dipyridamole or adenosine were available for diagnostic pharmacological vasodilation, but they were not approved for this indication.

METHODS

Data on safety and tolerability were prospectively collected from consecutive patients referred for the assessment of myocardial ischemia using myocardial scintigraphy. Data were immediately entered into a dedicated computer program.

RESULTS

After injection of regadenoson, there was a significant mean increase in heart rate from 70.2 ± 12.3 to a maximum of 94.6 ± 17.3 bpm. Systolic blood pressure dropped from 128.9 ± 16.2 to a minimum of 123.3 ± 20.3 mmHg. 86% of patients experienced any adverse effects, with the most frequent being dyspnea (64.2%), followed by headaches (20.7%), a sensation of warmth (20.2%), and numerous other, less frequent sensations. Bronchospasms were not observed, notably not in the 508 patients with COPD/ bronchial asthma. Asystole of > 6 s occurred in 2 patients (0.03%), which were both successfully terminated immediately with theophylline and atropine. There were no fatalities.

CONCLUSION

Overall, regadenoson demonstrated very good tolerability. The development of the selective A2A adenosine receptor agonist regadenoson, compared to classical non-selective adenosine, represents a significant advancement in non-invasive imaging diagnostics of myocardial ischemia, using myocardial scintigraphy and other modalities such as MRI. Since adenosine is contraindicated in patients with bronchial asthma/COPD, regadenoson has become the diagnostic agent of choice in these cases, although it must be considered that very rare instances (< 0.1%) of life-threatening events can occur, necessitating that antidotes such as theophylline and atropine be readily available.