Regadenoson Combined With Symptom-Limited Exercise in Patients Undergoing Myocardial Perfusion Imaging

The Ex-Lex Trial: A Randomized Trial Combining Regadenoson With Symptom-Limited Exercise in Patients Undergoing Myocardial Perfusion Imaging

Not infrequently, a physician is faced with uncertainty regarding the ability of a patient to perform adequate exercise in the noninvasive evaluation of known or suspected coronary artery disease (CAD) by the use of radionuclide stress myocardial perfusion imaging. In selected patients, protocols that combine exercise (either low-level or symptom-limited) with vasodilator stress agents have been found to be safe and effective in both identification of the presence and severity of CAD as well as risk stratification for adverse cardiac outcome. However, currently utilized combined stress protocols have drawbacks. Further refinement of combined stress protocols would potentially lead to more appropriate stress protocol selection for patients while enhancing laboratory efficiency. The purpose of this prospective, randomized study will be to evaluate the relative merits of combining regadenoson with symptom-limited exercise in patients clinically-referred for vasodilator-exercise stress myocardial perfusion imaging for the assessment of known or suspected CAD. It is hypothesized that combining regadenoson with symptom-limited exercise is a safe and feasible stress testing modality which is non-inferior to that which combines symptom-limited exercise with dipyridamole.

Inclusion Criteria:

• Males and non-pregnant, non-nursing females clinically referred for vasodilator stress myocardial perfusion imaging with the addition of exercise
• Age >=30 years

Exclusion Criteria:

• Extremely limited functional capacity
• Age <30 years
• Unable or unwilling to provide informed consent
• Pregnant or nursing females
• Current use of methylxanthines within 12 hours of testing
• Current use of dipyridamole or aminophylline within 48 hours of testing
• Uncontrolled hypertension (>200 mmHg systolic/>120 mmHg diastolic)
• Known hypertrophic cardiomyopathy with obstruction or severe aortic stenosis
• Decompensated congestive heart failure
• History of sick sinus syndrome or > first degree atrioventricular block in the absence of a functioning pacemaker
• Asthma or other bronchospastic reactive airway disease
• History of percutaneous coronary intervention or coronary artery bypass grafting, or documented history of acute myocardial infarction or unstable angina within one week of testing
• Patients at risk for hypotensive reaction to regadenoson