Arashi Hiroyuki, Yamaguchi Junichi, Ri Tonre, Otsuki Hisao, Nakao Masashi, Kamishima Kazuho, Jujo Kentaro, Minami Yuichiro, Ogawa Hiroshi, Hagiwara Nobuhisa
Department of Cardiology, The Heart Institute of Japan, Tokyo Women's Medical University, Tokyo, Japan.
Department of Cardiology, The Heart Institute of Japan, Tokyo Women's Medical University, Tokyo, Japan.
J Cardiol. 2018 Mar;71(3):237-243. doi: 10.1016/j.jjcc.2017.09.003. Epub 2017 Oct 17.
The instantaneous wave-free ratio (iFR) is a vasodilator-free, invasive pressure wire index of the functional severity of coronary stenosis and is calculated under resting conditions. In a recent study, iFR was found to be more closely linked to coronary flow reserve (CFR) than fractional flow reserve (FFR). E/e' is a surrogate marker of left ventricular (LV) filling pressure and LV diastolic dysfunction. Coronary resting flow was found to be increased in patients with elevated E/e', and higher coronary resting flow was associated with lower CFR. Higher baseline coronary flow induces a greater loss of translesional pressure and may affect iFR. However, no reports have examined the impact of E/e' on iFR. The purpose of this study was to assess the relationship between iFR and E/e' compared with FFR.
We retrospectively examined 103 consecutive patients (142 with stenosis) whose iFR, FFR, and E/e' were measured simultaneously. The mean age, LV mass index, and systolic blood pressure of patients with elevated E/e' were higher than those of patients with normal E/e'. Although no significant differences were observed in mean FFR values and % diameter stenosis, the mean iFR value in patients with elevated E/e' was significantly lower than that in patients with normal E/e'. The iFR was negatively correlated with E/e', while there was no correlation between FFR and E/e'. Multivariate analysis showed that E/e' and % diameter stenosis were independent determinants of iFR.
E/e' ratio affects iFR values. Our results suggest that FFR mainly reflects the functional severity of the epicardial stenosis whereas iFR could potentially be influenced by not only epicardial stenosis but also other factors related to LV filling pressure or LV diastolic dysfunction. Further research is needed to understand the underlying mechanisms that influence the evaluation of iFR in patients with elevated E/e'.
瞬时无波比值（iFR）是一种无需使用血管扩张剂的、通过侵入性压力导丝测定的冠状动脉狭窄功能严重程度指标，在静息状态下计算得出。在最近一项研究中，发现iFR与冠状动脉血流储备（CFR）的关联比血流储备分数（FFR）更为紧密。E/e'是左心室（LV）充盈压和LV舒张功能障碍的替代标志物。研究发现，E/e'升高的患者冠状动脉静息血流增加，而较高的冠状动脉静息血流与较低的CFR相关。较高的基线冠状动脉血流会导致跨病变压力损失更大，并可能影响iFR。然而，尚无报告研究E/e'对iFR的影响。本研究的目的是评估iFR与E/e'之间的关系，并与FFR进行比较。
我们回顾性研究了103例连续患者（142处狭窄），这些患者同时测量了iFR、FFR和E/e'。E/e'升高患者的平均年龄、LV质量指数和收缩压高于E/e'正常的患者。虽然平均FFR值和直径狭窄百分比无显著差异，但E/e'升高患者的平均iFR值显著低于E/e'正常的患者。iFR与E/e'呈负相关，而FFR与E/e'之间无相关性。多变量分析显示，E/e'和直径狭窄百分比是iFR的独立决定因素。
E/e'比值影响iFR值。我们的结果表明，FFR主要反映心外膜狭窄的功能严重程度，而iFR不仅可能受心外膜狭窄影响，还可能受与LV充盈压或LV舒张功能障碍相关的其他因素影响。需要进一步研究以了解影响E/e'升高患者iFR评估结果的潜在机制。
