Abstract
BackgroundAdenosine 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.MethodsSemiquantitative 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.ResultsGlobal 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).ConclusionCaffeine 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.
Highlights
Adenosine is used in stress perfusion cardiac imaging to reveal myocardial ischemia by its vasodilator effects
We sought to investigate in patients with substantial myocardial ischemia under caffeine-naïve conditions: 1) the effect of a defined caffeine intake on adenosine stress cardiovascular magnetic resonance imaging (CMR) using semiquantitative perfusion analysis of ischemic and remote myocardial segments, and 2) if the splenic switch-off sign, which has recently been suggested as indicator for adequate hyperemia [12], is sensitive to prior caffeine consumption
The cohort of this study was part of a previously reported trial, in which we found that caffeine consumption led to a slight reduction of perfusion defect size determined by visual assessment of adenosine stress CMR
Summary
Adenosine is used in stress perfusion cardiac imaging to reveal myocardial ischemia by its vasodilator effects. This study assessed the impact of caffeine on the myocardial perfusion reserve index (MPRI) using adenosine stress cardiovascular magnetic resonance imaging (CMR). There continues to be debate in the clinical routine, if a scheduled adenosine stress CMR should be cancelled, or performed in patients presenting with caffeine consumption during the last 12–24 h before the exam [11]. We sought to investigate in patients with substantial myocardial ischemia under caffeine-naïve conditions: 1) the effect of a defined caffeine intake on adenosine stress CMR using semiquantitative perfusion analysis of ischemic and remote myocardial segments, and 2) if the splenic switch-off sign, which has recently been suggested as indicator for adequate hyperemia [12], is sensitive to prior caffeine consumption
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