The QFR computation improved the diagnostic accuracy of 3-dimensional quantitative coronary angiography-based identification of stenosis significance. The favorable results of cQFR that does not require pharmacologic hyperemia induction bears the potential of a wider adoption of FFR-based lesion assessment through a reduction in procedure time, risk, and costs.

Pressure wire-based fractional flow reserve is considered the standard of reference for evaluation of the ischemic potential of coronary stenoses and the expected benefit from revascularization. Accordingly, its application in daily practice or for research purposes has to be as standardized as possible to avoid technical or operator-related artifacts in pressure recordings. This document proposes a standardized way of acquiring, recording, interpreting, and archiving the pressure tracings for daily practice and for the purpose of clinical research involving a core laboratory. Proposed standardized steps enhance the uniformity of clinical practices and data interpretation.

T he optimal treatment of patients with stable coronary artery disease (CAD) remains a matter of ongoing debate. Although revascularization provides an accepted symptomatic benefit, controversy lingers on its prognostic value when added to contemporary optimal medical care.1 Protagonists of medical therapy stress that revascularization, especially with percutaneous coronary intervention (PCI), does not reduce rates of death or myocardial infarction.2 Protagonists of mechanical therapy counter that most revascularization studies were based on anatomic guidance only, with visual estimation of stenosis severity from the coronary angiogram.3 Because ≤39% of angiographically obstructive coronary stenoses lack functional significance, no benefit should be expected from revascularizing nonischemic myocardium. 4 As a result, outcome results from existing trials are confounded by the neutral or negative effects arising from unnecessary interventions.

Background— The fractional flow reserve (FFR) value of 0.75 has been validated against ischemic testing, whereas the FFR value of 0.80 has been widely accepted to guide clinical decision making. However, revascularization when FFR is 0.76 to 0.80, within the so-called gray zone, is still debatable. Methods and Results— From February 1997 to June 2013, all patients with single-segment disease and an FFR value within the gray zone or within the 2 neighboring FFR strata (0.70–0.75 and 0.81–0.85) were included. Study end points consisted of major adverse cardiovascular events (death, myocardial infarction, and any revascularization) up to 5 years. Of 17 380 FFR measurements, 1459 patients were included. Of them, 449 patients were treated with revascularization and 1010 patients were treated with medical therapy. In the gray zone, the major adverse cardiovascular events rate was similar (37 [13.9%] versus 21 [11.2%], respectively; P =0.3) between medical therapy and revascularization, whereas a strong trend toward a higher rate of death or myocardial infarction (25 [9.4] versus 9 [4.8], P =0.06) and overall death (20 [7.5] versus 6 [3.2], P =0.059) was observed in the medical therapy group. Among medical therapy patients, a significant step-up increase in major adverse cardiovascular events rate was observed across the 3 FFR strata, especially with proximal lesion location. In revascularization patients, the major adverse cardiovascular events rate was not different across the 3 FFR strata. Conclusions— FFR in and around the gray zone bears a major prognostic value, especially in proximal lesions. These data confirm that FFR≤0.80 is valid to guide clinical decision making.

Absolute coronary blood flow (in L/min) and R (in mm Hg/L/min or Wood units) can be safely and reproducibly measured with continuous thermodilution. This approach constitutes a new opportunity for the study of the coronary microcirculation.

Background— Fractional flow reserve (FFR), an index of the hemodynamic severity of coronary stenoses, is derived from invasive measurements and requires a pressure-monitoring guidewire and hyperemic stimulus. Angiography-derived FFR measurements (FFR angio ) may have several advantages. The aim of this study is to assess the diagnostic performance and interobserver reproducibility of FFR angio in patients with stable coronary artery disease. Methods and Results— FFR angio is a computational method based on rapid flow analysis for the assessment of FFR. FFR angio uses the patient’s hemodynamic data and routine angiograms to generate a complete 3-dimensional coronary tree with color-coded FFR values at any epicardial location. Hyperemic flow ratio is derived from an automatic resistance-based lumped model of the entire coronary tree. A total of 203 lesions were analyzed in 184 patients from 4 centers. Values derived using FFR angio ranged from 0.5 to 0.97 (median 0.85) and correlated closely (Spearman ρ=0.90; P <0.001) with the invasive FFR measurements, which ranged from 0.5 to 1 (median 0.84). In Bland–Altman analyses, the 95% limits of agreement between these methods ranged from −0.096 to 0.112. Using an FFR cutoff value of 0.80, the sensitivity, specificity, and diagnostic accuracy of FFR angio were 88%, 95%, and 93%, respectively. The intraclass coefficient between 2 blinded operators was 0.962 with a 95% confidence interval from 0.950 to 0.971, P <0.001. Conclusions— There is a high concordance between FFR angio and invasive FFR. The color-coded display of FFR values during coronary angiography facilitates the integration of physiology and anatomy for decision making on revascularization in patients with stable coronary artery disease. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT03005028.

Background-The

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