BACKGROUND Recently, 2 randomized controlled trials showed that the instantaneous wave-free ratio (iFR), a resting coronary physiological index, is noninferior to fractional flow reserve for guiding revascularization. The resting distal to aortic coronary pressure (Pd/Pa) measured at rest is another adenosine-free index widely available in the cardiac catheterization laboratory; however, little is known about the agreement of Pd/Pa using iFR as a reference standard. OBJECTIVES The goal of this study was to investigate the agreement of Pd/Pa with iFR. METHODS A total of 763 patients were prospectively enrolled from 12 institutions. iFR and Pd/Pa were measured under resting conditions. Using iFR ≤0.89 as a reference standard, the agreement of Pd/Pa and its best cutoff value were assessed. RESULTS According to the independent core laboratory analysis, iFR and Pd/Pa were analyzable in 627 and 733 patients (82.2% vs. 96.1%; p < 0.001), respectively. The median iFR and Pd/Pa were 0.90 (interquartile range: 0.85 to 0.94) and 0.92 (interquartile range: 0.88 to 0.95), and the 2 indices were highly correlated (R2 = 0.93; p < 0.001; iFR = 1.31 * Pd/Pa -0.31). According to the receiver-operating characteristic curve analysis, Pd/Pa showed excellent agreement (area under the curve: 0.98; 95% confidence interval: 0.97 to 0.99; p < 0.001) with a best cutoff value of Pd/Pa ≤0.91. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 93.0%, 91.4%, 94.4%, 93.3%, and 92.7%, respectively. These results were similar in patients with acute coronary syndrome and stable angina. CONCLUSIONS Pd/Pa was analyzable in a significantly higher number of patients than iFR. Pd/Pa showed excellent agreement with iFR, suggesting that it could be applied clinically in a similar fashion. (Can Contrast Injection Better Approximate FFR Compared to Pure Resting Physiology? [CONTRAST]; NCT02184117).

中文翻译：

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静息远端到主动脉冠状动脉压力与瞬时无波比的一致性

背景 最近，2 项随机对照试验表明，瞬时无波比（iFR）是一种静息冠状动脉生理指标，在指导血运重建方面不劣于血流储备分数。静息时测得的静息远端冠状动脉压 (Pd/Pa) 是心导管插入实验室中广泛使用的另一种无腺苷指数；然而，关于使用 iFR 作为参考标准的 Pd/Pa 一致性知之甚少。目的 本研究的目的是调查 Pd/Pa 与 iFR 的一致性。方法 前瞻性纳入来自 12 个机构的 763 名患者。在静息条件下测量 iFR 和 Pd/Pa。使用 iFR ≤0.89 作为参考标准，评估 Pd/Pa 的一致性及其最佳截止值。结果 根据独立核心实验室分析，分别有 627 和 733 名患者的 iFR 和 Pd/Pa 可分析（82.2% 与 96.1%；p < 0.001）。iFR 和 Pd/Pa 的中位数分别为 0.90（四分位距：0.85 至 0.94）和 0.92（四分位距：0.88 至 0.95），两个指标高度相关（R2 = 0.93；p < 0.001；iFR = 1/31 * Pd帕 -0.31）。根据受试者工作特征曲线分析，Pd/Pa 显示出极好的一致性（曲线下面积：0.98；95% 置信区间：0.97 至 0.99；p < 0.001），Pd/Pa 的最佳截止值≤0.91。诊断准确率、敏感性、特异性、阳性预测值和阴性预测值分别为93.0%、91.4%、94.4%、93.3%和92.7%。这些结果在急性冠脉综合征和稳定型心绞痛患者中相似。结论 与 iFR 相比，Pd/Pa 可在显着更多的患者中进行分析。Pd/Pa 与 iFR 表现出极好的一致性，表明它可以以类似的方式应用于临床。（与纯静息生理相比，造影剂注射能否更好地近似 FFR？[对比]；NCT02184117）。