BACKGROUND Adenosine is used in stress perfusion cardiac imaging to reveal myocardial ischemia by its vasodilator effects. Caffeine is a competitive antagonist of adenosine. However, previous studies reported inconsistent results about the influence of caffeine on adenosine's vasodilator effect. This study assessed the impact of caffeine on the myocardial perfusion reserve index (MPRI) using adenosine stress cardiovascular magnetic resonance imaging (CMR). Moreover, we sought to evaluate if the splenic switch-off sign might be indicative of prior caffeine consumption. METHODS Semiquantitative perfusion analysis was performed in 25 patients who underwent: 1) caffeine-naïve adenosine stress CMR demonstrating myocardial ischemia and, 2) repeat adenosine stress CMR after intake of caffeine. MPRI (global; remote and ischemic segments), and splenic perfusion ratio (SPR) were assessed and compared between both exams. RESULTS Global MPRI after caffeine was lower vs. caffeine-naïve conditions (1.09 ± 0.19 vs. 1.24 ± 0.19; p <  0.01). MPRI in remote myocardium decreased by caffeine (1.24 ± 0.19 vs. 1.49 ± 0.19; p <  0.001) whereas MPRI in ischemic segments (0.89 ± 0.18 vs. 0.95 ± 0.23; p = 0.23) was similar, resulting in a lower MPRI ratio (=remote/ischemic segments) after caffeine consumption vs. caffeine-naïve conditions (1.41 ± 0.19 vs. 1.64 ± 0.35, p = 0.01). The SPR was unaffected by caffeine (SPR 0.38 ± 0.19 vs. 0.38 ± 0.18; p = 0.92). CONCLUSION Caffeine consumption prior to adenosine stress CMR results in a lower global MPRI, which is driven by the decreased MPRI in remote myocardium and underlines the need of abstinence from caffeine. The splenic switch-off sign is not affected by prior caffeine intake.

中文翻译：

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咖啡因对心肌灌注储备的影响通过半定量腺苷应激灌注心血管磁共振评估。

背景技术腺苷用于压力灌注心脏成像中以通过其血管扩张作用揭示心肌缺血。咖啡因是腺苷的竞争性拮抗剂。然而，先前的研究报道了关于咖啡因对腺苷的血管扩张作用的影响的不一致结果。这项研究使用腺苷应激心血管磁共振成像（CMR）评估了咖啡因对心肌灌注储备指数（MPRI）的影响。此外，我们试图评估脾脏关闭信号是否可以指示以前的咖啡因摄入量。方法对25例患者进行了半定量灌注分析：1）表现为心肌缺血的无咖啡因的腺苷应激CMR，以及2）摄入咖啡因后重复进行腺苷应激CMR。MPRI（全球；远程和局部缺血），两次检查之间评估并比较了脾脏灌注率（SPR）。结果与未经咖啡因的条件相比，咖啡因后的全球MPRI较低（1.09±0.19与1.24±0.19； p <0.01）。咖啡因使远端心肌的MPRI降低（1.24±0.19 vs. 1.49±0.19; p <0.001），而缺血段的MPRI（0.89±0.18 vs.0.95±0.23; p = 0.23）相似，导致MPRI比降低（ =摄入咖啡因后与未接受咖啡因的情况（远程/局部缺血）（1.41±0.19 vs. 1.64±0.35，p = 0.01）。SPR不受咖啡因的影响（SPR为0.38±0.19 vs. 0.38±0.18； p = 0.92）。结论腺苷应激CMR之前的咖啡因消耗会导致总体MPRI降低，这是由于远端心肌MPRI降低所致，并强调需要戒除咖啡因。