Long Island College Hospital, Brooklyn, NY 11201, USA.
J Nucl Cardiol. 2011 Feb;18(1):73-81. doi: 10.1007/s12350-010-9311-6. Epub 2010 Nov 17.
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.
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.
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).
咖啡因通过竞争性 A₂(A)受体阻断来减轻腺苷引起的冠状动脉扩张反应。本研究旨在确定在接受选择性腺苷 A(2A)激动剂雷卡地诺松行血管扩张剂负荷心肌灌注成像（MPI）的患者中，口服咖啡因是否会影响诊断准确性。
这是一项多中心、随机、双盲、安慰剂对照、平行组研究，纳入了经常摄入咖啡因的疑似冠心病患者。每位参与者进行三次 SPECT MPI 研究：第 1 天的静息研究（MPI-1）；第 3 天的雷卡地诺松应激研究（MPI-2），以及第 5 天的雷卡地诺松应激研究，同时给予口服 200 或 400mg 咖啡因或安慰剂胶囊（MPI-3；每组 90 名参与者）。只有在第二次 MPI 研究中有≥1 个可逆缺陷的参与者才进行随后的应激性 MPI 测试。主要终点是使用 17 节段模型比较两次应激测试中可逆缺陷的数量差异。药代动力学/药效学分析将评估咖啡因对雷卡地诺松暴露-反应关系的影响。还将评估安全性。
该研究结果将显示在接受雷卡地诺松 MPI 研究前摄入相当于 2-4 杯咖啡的咖啡因是否会影响应激测试的诊断有效性（临床试验编号：NCT00826280）。
