Instantaneous wave free ratio

Percutaneous coronary intervention is increasingly guided by coronary physiology and optimized using intravascular imaging. Pressure-based measurements determine the significance of a stenosis using hyperemic or nonhyperemic pressure ratios (eg, the instantaneous wave-free ratio). Intravascular ultrasound and optical coherence tomography provide cross-sectional and longitudinal detail regarding plaque composition and vessel characteristics. These facilitate lesion preparation and optimization of stent sizing and positioning...

Coronary physiologic assessment has become a standard of care for patients with coronary atherosclerotic disease. While most attention has focused on pre-interventional physiologic assessment to aid in revascularization decision-making, post-interventional physiologic assessment has not been as widely used, despite evidence supporting its role in assessment and optimization of the revascularization procedure. A thorough understanding of such evidence and ongoing studies would be crucial to incorporate post-interventional physiologic assessment into daily practice...

Modern coronary intervention requires integration of angiographic, physiologic, and intravascular imaging. This article describes the use and techniques needed to understand coronary physiology pullback data and how use it to make revascularization decisions. The article describes instantaneous wave-free ratio, fractional flow reserve, and the data that support their use and how they differ when used in tandem disease. Common practical mistakes and errors are discussed together with a brief review of the limited published research data...

Despite the now routine integration of invasive physiologic systems into coronary catheter laboratories worldwide, it remains critical that all operators maintain a sound understanding of the fundamental physiologic basis for coronary pressure assessment. More specifically, performing operators should be well informed regarding the basis for hyperemic (ie, fractional flow reserve) and nonhyperemic (ie, instantaneous wave-free ratio and other nonhyperemic pressure ratio) coronary pressure assessment. In this article, we provide readers a comprehensive history charting the inception, development, and validation of hyperemic and nonhyperemic coronary pressure assessment...

For image-based computational fluid dynamics (CFD) analysis to characterize the local coronary hemodynamic environment, the accuracy depends on the flow rate which is in turn associated with outlet branches' morphology. A good flow distribution strategy is important to mitigate the effect when certain branches cannot be considered. In this study, stenotic coronary arteries from 13 patients were used to analyze the effect of missing branches and different flow distribution strategies. Pressure- and wall shear stress (WSS)-derived parameters around the stenotic region (ROI) were compared, including fractional flow reserve (CT-FFR), instantaneous wave-free ratio (CT-iFR), resting distal to aortic coronary pressure (CT-Pd/Pa), time-averaged WSS, oscillatory shear index (OSI) and relative residence time (RRT)...

The management strategies for anomalous aortic origin of a coronary artery (AAOCA) are based on anatomy, symptoms, and stress tests for evidence of ischemia. These strategies remain associated with low levels of evidence. Stress tests for ischemia or ventricular dysfunction, the only widely used physiological tests, are not adequately reliable. Additional physiological metrics are needed to build reliable strategies. Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are physiological measurements that are used in assessing acquired coronary artery disease (CAD)...

No abstract text is available yet for this article.

Background and Objectives : Coronary angiography is the gold standard for diagnosing coronary artery disease (CAD). In the case of borderline changes, patients require further diagnosis through ischemia assessment via one of the recommended methods of invasive evaluation. This study aimed to assess whether clinical factors influence the risk of a positive result in invasive myocardial ischemia assessment and if these potential factors change with the patient's age and the consistency of ischemia assessment...

BACKGROUND/PURPOSE: It is unclear whether coronary physiology or coronary angiography (CA)-guided strategy is the more preferable approach for deferring percutaneous coronary intervention (PCI). We sought to evaluate the clinical efficacy of various PCI strategies through a network meta-analysis of randomized controlled trials (RCTs). METHODS/MATERIALS: We searched multiple databases for RCTs investigating the impact of the following strategies for the purpose of determining whether or not to defer PCI: fractional flow reserve, instantaneous wave-free ratio, quantitative flow ratio (QFR), and CA...

No abstract text is available yet for this article.

BACKGROUND: Fractional flow reserve-computed tomography (FFRCT ) has not been validated in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) for coronary artery disease due to theoretical difficulties in using nitroglycerin for such patients.Methods and Results: In this single-center study, we prospectively enrolled 21 patients (34 vessels) and performed pre-TAVR FFRCT without nitroglycerin, pre-TAVR invasive instantaneous wave-free ratio (iFR) measurements, and post-TAVR FFR measurements using a pressure wire...

To evaluate the differential associations of high-risk plaque characteristics (HRPC) with resting or hyperemic physiologic indexes (instantaneous wave-free ratio [iFR] or fractional flow reserve [FFR]), a total of 214 vessels from 127 patients with stable angina or acute coronary syndrome who underwent coronary computed tomography angiography (CCTA) and invasive physiologic assessment were investigated. HPRC were classified into quantitative (minimal luminal area < 4 mm2 or plaque burden ≥ 70%) and qualitative features (low attenuation plaque, positive remodeling, napkin ring sign, or spotty calcification)...

BACKGROUND: Angiography-derived computational physiology is an appealing alternative to pressure-wire coronary physiology assessment. However, little is known about its reliability in the setting of severe aortic stenosis. This study sought to provide an integrated assessment of epicardial and microvascular coronary circulation by means of single-view angiography-derived physiology in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI). METHODS: Pre-TAVI angiographic projections of 198 stenotic coronary arteries (123 patients) were analyzed by means of Murray's law-based quantitative flow ratio and angiography microvascular resistance...

Coronary angiography has a limited ability to predict the functional significance of intermediate coronary lesions. Hence, physiological assessment of coronary lesions, via fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR), has been introduced to determine their functional significance. An accumulating body of evidence has consolidated the role of physiology-guided revascularization, particularly among patients with stable ischemic heart disease. The use of FFR or iFR to guide decision-making in patients with stable ischemic heart disease and intermediate coronary lesions received a class I recommendation from major societal guidelines...

No abstract text is available yet for this article.

No abstract text is available yet for this article.

BACKGROUND AND AIMS: Guidelines recommend revascularization of intermediate epicardial artery stenosis to be guided by evidence of ischemia. Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are equally recommended. Individual 5-year results of two major randomized trials comparing FFR with iFR-guided revascularization suggested increased all-cause mortality following iFR-guided revascularization. The aim of this study was a study-level meta-analysis of the 5-year outcome data in iFR-SWEDEHEART (NCT02166736) and DEFINE-FLAIR (NCT02053038)...

Recently, instantaneous wave-free ratio (iFR) has emerged as an alternative to the fractional flow reserve (FFR) for intracoronary physiological assessment. Although all diastolic resting indices are reportedly identical to the iFR, limited data exist on diastolic pressure ratio (dPR) measured using a microcatheter (dPRmicro ). This study aimed to evaluate the diagnostic accuracy of dPRmicro compared to FFR measured using a microcatheter (FFRmicro ) in real-world practice for intracoronary physiological assessment...

BACKGROUND: Landmark trials showed that invasive pressure measurement (Fractional Flow Reserve, FFR) was a better guide to coronary stenting than visual assessment. However, present-day interventionists have benefited from extensive research and personal experience of mapping anatomy to hemodynamics. AIMS: To determine if visual assessment of the angiogram performs as well as invasive measurement of coronary physiology. METHODS: 25 interventional cardiologists independently visually assessed the single vessel coronary disease of 200 randomized participants in The Objective Randomized Blinded Investigation with optimal medical Therapy of Angioplasty in stable angina trial (ORBITA)...

BACKGROUND: The pressure-derived parameters fractional flow reserve (FFR) and the emerging instantaneous wave-free ratio (iFR) are the most widely applied invasive coronary physiology indices to guide revascularisation. However, approximately 15-20% of intermediate stenoses show discordant FFR and iFR, and therapeutical consensus is lacking. AIMS: We sought to associate hyperaemic stenosis resistance index, coronary flow reserve (CFR) and coronary flow capacity (CFC) to FFR/iFR discordance...