Background. The resting full‐cycle ratio (RFR) is a novel resting index which in contrast to the gold standard (fractional flow reserve (FFR)) does not require maximum hyperemia induction. The objectives of this study were to evaluate the agreement between RFR and FFR with the currently recommended thresholds and to design a hybrid RFR-FFR ischemia detection strategy, allowing a reduction of coronary vasodilator use. Materials and Methods. Patients subjected to invasive physiological study in 9 Spanish centers were prospectively recruited between April 2019 and March 2020. Sensitivity and specificity studies were made to assess diagnostic accuracy between the recommended levels of RFR ≤0.89 and FFR ≤0.80 (primary objective) and to determine the RFR “grey zone” in order to define a hybrid strategy with FFR affording 95% global agreement compared with FFR alone (secondary objective). Results. A total of 380 lesions were evaluated in 311 patients. Significant correlation was observed (R² = 0.81; ) between the two techniques, with 79% agreement between RFR ≤ 0.89 and FFR ≤ 0.80 (positive predictive value, 68%, and negative predictive value, 80%). The hybrid RFR-FFR strategy, administering only adenosine in the “grey zone” (RFR: 0.86 to 0.92), exhibited an agreement of over 95% with FFR, with high predictive values (positive predictive value, 91%, and negative predictive value, 92%), reducing the need for vasodilators by 58%. Conclusions. Dichotomous agreement between RFR and FFR with the recommended thresholds is significant but limited. The adoption of a hybrid RFR-FFR strategy affords very high agreement, with minimization of vasodilator use.

中文翻译：

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混合RFR-FFR方法的有用性：RFR和FFR之间的诊断协议的前瞻性和多中心分析的结果-RECOPA（重新研究全循环比与分数流量储备（预期验证））

背景。静息全周期比率（RFR）是一种新颖的静息指数，与黄金标准（分数血流储备（FFR））相比，不需要最大程度的充血。这项研究的目的是评估RFR和FFR与当前推荐的阈值之间的一致性，并设计一种混合的RFR-FFR缺血检测策略，从而减少冠状动脉血管扩张剂的使用。材料和方法。在2019年4月至2020年3月之间前瞻性招募了在9个西班牙中心进行侵入性生理研究的患者。进行了敏感性和特异性研究，以评估RFR≤0.89和FFR≤0.80（主要目标）的推荐水平的诊断准确性，并确定RFR“灰色地带”是为了定义一种混合策略，即与单独的FFR（次要目标）相比，FFR可以提供95％的全球协议。结果。311例患者总共评估了380个病变。观察到显着的相关性（R ²  = 0.81；）之间的差异，RFR≤0.89和FFR≤0.80的一致性为79％（阳性预测值68％，阴性预测值80％）。RFR-FFR混合策略仅在“灰色区域”（RFR：0.86至0.92）中使用腺苷，与FFR的一致性超过95％，具有较高的预测值（阳性预测值，91％和阴性预测值） （92％），将血管扩张药的需求减少了58％。结论。RFR和FFR与建议的阈值之间的二分式一致性很重要，但很有限。RFR-FFR混合策略的采用提供了很高的共识，并最大程度地减少了血管扩张剂的使用。