title: Effect of caffeine on SPECT myocardial perfusion imaging during regadenoson pharmacologic stress: rationale and design of a prospective, randomized, multicenter study.
abstract: BACKGROUND
  Caffeine attenuates the coronary hyperemic response to adenosine by competitive A₂(A) receptor blockade. This study aims to determine whether oral caffeine administration compromises diagnostic accuracy in patients undergoing vasodilator stress myocardial perfusion imaging (MPI) with regadenoson, a selective adenosine A(2A) agonist.
  
  
  METHODS
  This multicenter, randomized, double-blind, placebo-controlled, parallel-group study includes patients with suspected coronary artery disease who regularly consume caffeine. Each participant undergoes three SPECT MPI studies: a rest study on day 1 (MPI-1); a regadenoson stress study on day 3 (MPI-2), and a regadenoson stress study on day 5 with double-blind administration of oral caffeine 200 or 400 mg or placebo capsules (MPI-3; n = 90 per arm). Only participants with ≥ 1 reversible defect on the second MPI study undergo the subsequent stress MPI test. The primary endpoint is the difference in the number of reversible defects on the two stress tests using a 17-segment model. Pharmacokinetic/pharmacodynamic analyses will evaluate the effect of caffeine on the regadenoson exposure-response relationship. Safety will also be assessed.
  
  
  CONCLUSIONS
  The results of this study will show whether the consumption of caffeine equivalent to 2-4 cups of coffee prior to an MPI study with regadenoson affects the diagnostic validity of stress testing (ClinicalTrials.gov number, NCT00826280).
authors.affiliation: Long Island College Hospital, Brooklyn, NY 11201, USA. fht786@pol.net
authors.forename: Furqan H
authors.initials: FH
authors.lastname: Tejani
authors.forename: Randall C
authors.initials: RC
authors.lastname: Thompson
authors.forename: Ami E
authors.initials: AE
authors.lastname: Iskandrian
authors.forename: Bruce E
authors.initials: BE
authors.lastname: McNutt
authors.forename: Billy
authors.initials: B
authors.lastname: Franks
mesh_terms: D058917:Adenosine A2 Receptor Antagonists; D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002110:Caffeine / Q000008:administration & dosage*; D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography / Q000379:methods*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005080:Exercise Test / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D015995:Prevalence; D011446:Prospective Studies; D011687:Purines / Q000008:administration & dosage; D011720:Pyrazoles / Q000008:administration & dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014481:United States; D055815:Young Adult
chemical_list: D058917:Adenosine A2 Receptor Antagonists; D000697:Central Nervous System Stimulants; D011687:Purines; D011720:Pyrazoles; C430916:regadenoson; D002110:Caffeine