Weatherhead PET Center, Division of Cardiology, Department of Medicine, McGovern Medical School at UTHealth and Memorial Hermann Hospital, Houston, TX, USA.
Boston Scientific Corporation, CA, USA.
Eur Heart J. 2019 Aug 14;40(31):2585-2594. doi: 10.1093/eurheartj/ehz230.
The instantaneous wave-free ratio (iFR) and whole-cycle Pd/Pa investigate coronary physiology during non-hyperaemic conditions. To test for unique physiologic properties of the wave-free period when making resting coronary pressure measurements, we compared post hoc a diastolic pressure ratio (dPR) and Pd/Pa against iFR for numerical similarity and test/retest repeatability.
Eight hundred and ninety-three lesions from 833 subjects were included from the VERIFY 2 and CONTRAST studies. Diastolic pressure ratio and a linear transform of Pd/Pa were compared against iFR for diagnostic performance. Mean difference between dPR and iFR [Δ = -0.006 ± 0.011, r2 = 0.993, area under receiver operating characteristic (ROC) curve (AUC) = 0.997] mirrored the difference of two iFR measurements repeated immediately (Δ = <0.001 ± 0.004, r2 = 0.998, AUC = 1.00). Minor variations in the definition of dPR changed its value by <1-2% over a broad range of the cardiac cycle. A linear transform of Pd/Pa showed very good diagnostic performance (Δ = -0.012 ± 0.031, r2 = 0.927, AUC = 0.979). Post hoc iFR values were validated against real-time iFR values and matched almost exactly (average Δ = <0.001 ± 0.004, 99.6% within ±0.01).
Our dPR offers numerical equivalency to iFR. Despite different technical approaches for identifying the relevant period of diastole, the agreement between dPR and iFR and the insensitivity of dPR to minor variations in its definition further confirm numerical equivalency among resting metrics.
瞬时无波比（iFR）和全周期 Pd/Pa 在非充血状态下研究冠状动脉生理学。为了在进行静息冠状动脉压力测量时检验无波期的独特生理特性，我们对舒张压比值（dPR）和 Pd/Pa 与 iFR 进行了数值相似性比较和测试/复测重复性检验。
VERIFY 2 和 CONTRAST 两项研究共纳入了 833 例患者的 893 处病变。比较了 dPR 和 Pd/Pa 的线性变换与 iFR 的诊断性能。dPR 与 iFR 的平均差值[Δ=-0.006±0.011，r2=0.993，受试者工作特征曲线（ROC）下面积（AUC）=0.997]反映了即刻重复两次 iFR 测量的差值[Δ= <0.001±0.004，r2=0.998，AUC=1.00]。dPR 定义的微小变化会导致其在广泛的心动周期范围内变化 <1-2%。Pd/Pa 的线性变换显示出非常好的诊断性能（Δ=-0.012±0.031，r2=0.927，AUC=0.979）。我们还对 iFR 进行了实时验证，结果几乎完全一致（平均Δ= <0.001±0.004，99.6%在±0.01 以内）。
我们的 dPR 与 iFR 具有数值等效性。尽管识别相关舒张期的技术方法不同，但 dPR 与 iFR 的一致性以及 dPR 对其定义的微小变化不敏感，进一步证实了静息指标之间的数值等效性。
