1.
Effect of caffeine on SPECT myocardial perfusion imaging during regadenoson pharmacologic stress: rationale and design of a prospective, randomized, multicenter study.
Tejani, FH, Thompson, RC, Iskandrian, AE, McNutt, BE, Franks, B
Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology. 2011;(1):73-81
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. CONCLUSION 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).
2.
Does the Dundee Step Test predict outcome in treated hypertension? A sub-study protocol for the ASCOT trial. Anglo-Scandinavian Cardiac Outcome Trial.
Lim, PO, Donnan, PT, MacDonald, TM
Journal of human hypertension. 2000;(1):75-8
Abstract
Treated hypertensive subjects may remain five times more likely to die of cardiac and cerebrovascular diseases than normotensive subjects with equivalent resting blood pressure (BP) levels. Research evidence suggests that exercise BP is a better predictor of end-organ damage and mortality than resting BP, and data from our centre show that a significant proportion of treated hypertensives have uncontrolled BP during a 5-min Dundee Step Test. The prognostic usefulness of exercise BP has yet to be translated into clinical practice because of the lack of a suitable technique. The Dundee Step Test is being evaluated in the ASCOT (Anglo-Scandinavian Cardiac Outcome Trial) study, a 5-year follow-up multicentre, multinational trial comparing the effect of newer (amlodipine and perindopril) and older (bendroflumethiazide and atenolol) antihypertensive agents stratified according to cholesterol levels on cardiac outcome. If the value of the Dundee Step Test is proven, then it may be adopted into routine clinical practice for the assessment of exercise BP. This may result in the improved management of hypertension with a subsequent reduction in morbidity and mortality. The publication of this study protocol is meant to be a statement of on-going research which may stimulate interest among those with an interest in this area of research. Journal of Human Hypertension (2000) 14, 75-78.