Aims To assess the impact of adenosine on quantitative myocardial blood flow (MBF) in a rapid stress-rest protocol compared to a rest-stress protocol using 13N-ammonia positron emission tomography (PET) myocardial perfusion imaging (MPI) and to gain insights into the time dependency of such effects. Methods and results Quantitative MBF at rest (rMBF), during adenosine-induced stress (sMBF) and myocardial flow reserve (MFR) were obtained from 331 retrospectively identified patients who underwent 13N-ammonia PET-MPI for suspected chronic coronary syndrome and who all exhibited no perfusion defects. Of these, 146 (44.1%) underwent a rapid stress-rest protocol with a time interval (Δtstress-rest) of 20 ± 4 minutes between adenosine infusion offset and rest-imaging, as per clinical routine. The remaining 185 (55.9%) patients underwent a rest-stress protocol and served as the reference. Groups did not differ regarding demographics, risk factors, medication, left ventricular function, and calcium scores. rMBF was significantly higher in the stress-rest vs. the rest-stress group (0.80 [IQR 0.66-1.00] vs. 0.70 [0.58-0.83] ml·min-1·g-1, p < 0.001) and, as sMBF was identical between groups (2.52 [2.20-2.96] vs. 2.50 [1.96-3.11], p = 0.347), MFR was significantly lower in the stress-rest group (3.07 [2.43-3.88] vs. 3.50 [2.63-4.10], p < 0.001). There was a weak correlation between Δtstress-rest and rMBF (r = -0.259, p = 0.002) and between Δtstress-rest and MFR (r = 0.163, p = 0.049), and the proportion of patients with abnormally high rMBF was significantly decreasing with increasing Δtstress-rest. Conclusions Intravenously applied adenosine induces a long-lasting hyperemic effect on the myocardium. Consequently, rapid stress-rest protocols could lead to an overestimation of rMBF and an underestimation of MFR.

中文翻译：

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腺苷诱导的心肌充血的持续时间——定量 13N-氨正电子发射断层扫描心肌灌注成像的见解

目的 使用 13N-氨正电子发射断层扫描 (PET) 心肌灌注成像 (MPI) 评估快速应激休息方案与休息应激方案中腺苷对定量心肌血流量 (MBF) 的影响，并深入了解这种影响的时间依赖性。方法和结果 静息时定量 MBF (rMBF)、腺苷诱导应激期间 (sMBF) 和心肌血流储备 (MFR) 是从 331 名回顾性鉴定的患者中获得的，这些患者因疑似慢性冠状动脉综合征而接受 13N-氨 PET-MPI，并且所有患者都表现出无灌注缺陷。其中，146 例 (44.1%) 接受了快速应激休息方案，按照临床常规，腺苷输注补偿和休息成像之间的时间间隔 (Δtstress-rest) 为 20 ± 4 分钟。其余 185 名 (55.9%) 患者接受了休息应激方案并作为参考。各组在人口统计学、危险因素、药物、左心室功能和钙评分方面没有差异。与休息应激组相比，应激休息组的 rMBF 显着更高（0.80 [IQR 0.66-1.00] vs. 0.70 [0.58-0.83] ml·min-1·g-1，p < 0.001），并且，组间 sMBF 相同（2.52 [2.20-2.96] vs. 2.50 [1.96-3.11]，p = 0.347），压力休息组的 MFR 显着较低（3.07 [2.43-3.88] vs. 3.50 [2.63-4.10] ]，p＜0.001)。 Δtstress-rest 与 rMBF 之间（r = -0.259，p = 0.002）以及 Δtstress-rest 与 MFR 之间（r = 0.163，p = 0.049）之间存在弱相关性，并且 rMBF 异常高​​的患者比例显着下降随着 Δt 应力休息的增加。结论 静脉注射腺苷可引起心肌长期充血作用。因此，快速的压力休息方案可能会导致 rMBF 的高估和 MFR 的低估。