No abstract

cFFR provides diagnostic performance superior to that of Pd/Pa or iFR for predicting FFR. For clinical scenarios or health care systems in which adenosine is contraindicated or prohibitively expensive, cFFR offers a universal technique to simplify invasive coronary physiological assessments. Yet FFR remains the reference standard for diagnostic certainty as even cFFR reached only ∼85% agreement.

All diastolic resting indexes tested were identical to iFR, both numerically and with respect to their agreement with FFR. A numerically equal value to iFR can be determined without restriction to the WFP. Cutoff values, guidelines, and clinical recommendations for iFR can therefore be extended to these other indexes. (Pd/Pa vs iFR in an Unselected Population Referred for Invasive Angiography [VERIFY2]; NCT02377310).

Objectives To identify clinical, angiographic and hemodynamic predictors of discordance between instantaneous wave‐free ratio (iFR) and fractional flow reserve (FFR). Background The iFR was found to be non‐inferior to the gold‐standard FFR for guiding coronary revascularization, although it is discordant with FFR in 20% of cases. A better understanding of the causes of discordance may enhance application of these indices. Methods Both FFR and iFR were measured in the prospective multicenter CONTRAST study. Clinical, angiographic and hemodynamic variables were compared between patients with concordant values of FFR and iFR (cutoff ≤0.80 and ≤0.89, respectively). Results Out of the 587 patients included, in 466 patients (79.4%) FFR and iFR agreed: both negative, n = 244 (41.6%), or positive, n = 222 (37.8%). Compared with FFR, iFR was negative discordant (FFR+/iFR‐) in 69 (11.8%) patients and positive discordant (FFR‐/iFR+) in 52 (8.9%) patients. On multivariate regression, stenosis location (left main or proximal left anterior descending) (OR: 3.30[1.68;6.47]), more severe stenosis (OR: 1.77[1.35;2.30]), younger age (OR: 0.93[0.90;0.97]), and slower heart rate (OR: 0.59[0.42;0.75]) were predictors of a negative discordant iFR. Absence of a beta‐blocker (OR: 0.41[0.22;0.78]), older age (OR: 1.04[1.00;1.07]), and less severe stenosis (OR: 0.69[0.53;0.89]) were predictors of a positive discordant iFR. Conclusions During iFR acquisition, stenosis location, stenosis degree, heart rate, age and use of beta blockers influence concordance with FFR and should be taken into account when interpreting iFR.

Coronary artery disease (CAD) is a leading global cause of morbidity and mortality, and improvements in the diagnosis and treatment of CAD can reduce the health and economic burden of this condition. Fractional flow reserve (FFR) is an evidence-based diagnostic test of the physiological significance of a coronary artery stenosis. Fractional flow reserve is a pressure-derived index of the maximal achievable myocardial blood flow in the presence of an epicardial coronary stenosis as a ratio to maximum achievable flow if that artery were normal. When compared with standard angiography-guided management, FFR disclosure is impactful on the decision for revascularization and clinical outcomes. In this article, we review recent developments with FFR in patients with stable CAD and recent myocardial infarction. Specifically, we review novel developments in our understanding of CAD pathophysiology, diagnostic applications, prognostic studies, clinical trials, and clinical guidelines.

BackgroundThe majority of coronary bifurcation lesions are treated with a provisional single‐stent strategy rather than an up‐front 2‐stent strategy. This approach is supported by multiple randomized controlled clinical trials with short‐ to medium‐term follow‐up; however, long‐term follow‐up data is evolving from many data sets.Methods and ResultsMeta‐analysis of randomized controlled trials evaluating long‐term outcomes (≥1 year) according to treatment strategy for coronary bifurcation lesions. Nine randomized controlled trials with 3265 patients reported long‐term clinical outcomes at mean weighted follow‐up of 3.1±1.8 years. Provisional single stenting was associated with lower all‐cause mortality (2.94% versus 4.23%; risk ratio: 0.69; 95% confidence interval, 0.48–1.00; P=0.049; I2=0). There was no difference in major adverse cardiac events (15.8% versus 15.4%; P=0.79), myocardial infarction (4.8% versus 5.5%; P=0.51), target lesion revascularization (9.3% versus 7.6%; P=0.19), or stent thrombosis (1.8% versus 1.6%; P=0.28) between the groups. Prespecified sensitivity analysis of long‐term mortality at a mean of 4.7 years of follow‐up showed that the provisional single‐stent strategy was associated with reduced all‐cause mortality (3.9% versus 6.2%; risk ratio: 0.63; 95% confidence interval, 0.42–0.97; P=0.036; I2=0).ConclusionsCoronary bifurcation percutaneous coronary intervention using a provisional single‐stent strategy is associated with a reduction in all‐cause mortality at long‐term follow‐up.

Aims 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. Methods and results 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). Conclusions 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.

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02377310.