Clinical Utility of Regadenoson for Assessing Fractional Flow Reserve

Objectives The aim of this study was to evaluate the efficacy of regadenoson, in comparison with adenosine, for assessing fractional flow reserve (FFR) of intermediate coronary artery stenoses (CAS). Background Fractional flow reserve is an established invasive method for assessing the physiological significance of CAS. Regadenoson, a selective A(2A) receptor agonist, is an approved hyperemic agent for pharmacological stress imaging, but its role for measuring FFR is unknown. Methods This prospective, single-center study enrolled 25 consecutive patients with intermediate CAS discovered during elective angiography (25 lesions). In each patient, FFR of the CAS was measured first by IV adenosine (140 mu g/kg/min), followed by IV regadenoson (400 mu g bolus). The intrapatient FFR correlation between adenosine and regadenoson was evaluated. Results The mean age was 63 11 years, and mean left ventricular ejection fraction was 58 11%. Most patients were male (52%) and had hypertension (84%) and dyslipidemia (84%), with 24% having diabetes mellitus and 20% chronic obstructive pulmonary disease. The CAS was visually estimated during angiography (mean 58 +/- 9%) and most often found in the left anterior descending coronary artery (48%). A strong, linear correlation of FFR was noted with adenosine and regadenoson (r = 0.985, p < 0.001). A hemodynamically significant lesion (FFR <= 0.80) was present in 52% with no reclassification of significance between adenosine and regadenoson. No serious events occurred with administration of either drug. Conclusions Our results suggest that a single IV bolus of regadenoson is as effective as an intravenous infusion of adenosine for measuring FFR and, given its ease of use, should be considered for FFR measurement in the catheterization laboratory. (J Am Coll Cardiol Intv 2011;4:1085-92) (C) 2011 by the American College of Cardiology Foundation