Myocardial Blood Flow by PET and N-13 Ammonia During Regadenoson vs Adenosine Stress

The hypothesis for this study was that Regadenoson will produce a very similar degree of maximal hyperemia (increased blood flow) as adenosine, the other vasodilator agent. There were only 2 days on study for each subject.

On Day 1 of the study, subjects were interviewed and had a physical exam, including a resting 12-lead electrocardiogram (ECG) to exclude evidence of silent ischemia or myocardial infarction, and other cardiovascular disorders. Subjects were instructed to have a light meal at least 4 hours prior to the PET MPI. Subjects were instructed to abstain from caffeine-containing products for 24 hours prior to the PET scan. Day 1 of the study occurred less than or equal to 4 weeks of Day 2.

On Day 2 of the study, each subject underwent three PET N-13 ammonia (10-20 mCi) dynamic emission acquisitions: resting, regadenoson (0.4 mg/5 mL IV), and adenosine (140 microgram/kg/min; order of regadenoson vs adenosine was randomized according to subject's birth year), and three transmission acquisitions for attenuation correction. Each emission acquisition was separated by 50 min to allow for radioactive decay. At the end of the drug infusions, subjects were monitored for 5-30 min. Based on the known short biological half-lives of these stress agents, the pharmacologic effects of each drug should have dissipated by the time the next drug was administered.

Inclusion criteria

• Healthy male and female volunteers over the age of 30.
• Written informed consent will be obtained from each subject.
• Each subject will undergo a history and physical examination

Exclusion criteria

• Any cardiovascular or pulmonary symptoms or exam findings
• History of low blood pressure (< 90/50 mmHg)
• Prior cardiac history
• History of hypertension
• History of hyperlipidemia
• History of diabetes mellitus
• History of asthma or chronic obstructive pulmonary disease
• Weight of > 450 pounds
• Chronic kidney disease
• Other serious illness such as cancer
• Current smoking
• Medication use (with the exception of acetaminophen, aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and thyroid hormone replacement)
• Illicit drug use
• Prior allergic reaction to adenosine, regadenoson, or aminophylline
• Pregnancy