Angio-Based Fractional Flow Reserve, Functional Pattern of Coronary Artery Disease, and Prediction of Percutaneous Coronary Intervention Result: a Proof-of-Concept Study

The role of advanced physiological guidance in contemporary coronary artery disease management

PURPOSE OF REVIEW

This review evaluates the emerging role of the pullback pressure gradient (PPG) as a standardized metric for assessing coronary artery disease (CAD) patterns and its implications for clinical decision-making when managing patients undergoing percutaneous coronary interventions (PCIs). By integrating PPG with existing physiological assessments, this review highlights the potential benefits of PPG in predicting treatment outcomes and refining therapeutic strategies for CAD.

RECENT FINDINGS

Recent studies, particularly the PPG Global study have demonstrated a strong correlation between PPG values and post-PCI outcomes, revealing that focal disease is associated with improved fractional flow reserve (FFR) and lower rates of adverse events than vessels with diffuse disease (low PPG). Additionally, PPG has been linked to specific atherosclerotic plaque characteristics, indicating its utility in identifying high-risk plaques. The integration of PPG with advanced imaging techniques further enhances the understanding of CAD patterns and their implications for treatment planning.

SUMMARY

The PPG represents a significant advancement in the management of CAD, providing a reproducible and objective assessment of coronary artery disease patterns that can inform clinical decision-making. As research continues to explore the relationship among PPG, atherosclerotic characteristics, and patient outcomes, its integration into routine practice is expected to improve the effectiveness of PCI and optimize patient management strategies. Future studies are warranted to establish specific PPG thresholds and further investigate its potential in identifying vulnerable plaques and guiding treatment decisions.

Coronary Physiology to Guide Percutaneous Coronary Intervention: Why, When, and How

Over most of the history of interventional cardiology, it has been tacitly assumed that once flow-limiting coronary disease had been documented, angiography was sufficient to plan percutaneous coronary intervention (PCI) and, subsequently, to decide if an optimal procedural result had been achieved. This view has been challenged by recent studies evaluating the results of PCI with fractional flow reserve and nonhyperemic pressure ratios. Evidence has accumulated showing that suboptimal functional PCI results occur frequently despite a good angiographic result and that they are associated with worse patient outcomes. In this article, we discuss how available coronary physiology tools, either guide wire or image-based, may address this problem by facilitating better procedural planning and PCI precision and optimization.

Efficacy of tanshinone IIA in rat models with myocardial ischemia-reperfusion injury: a systematic mini-review and meta-analysis

Background

Myocardial ischemia-reperfusion injury (MIRI) refers to severe damage to the ischemic myocardium following the restoration of blood flow, and it is a major complication of reperfusion therapy for myocardial infarction. Notably, drugs such as metoprolol have been utilized to reduce ischemia-reperfusion injury. Tanshinone IIA is a major constituent extracted from Salvia miltiorrhiza Bunge. Recently, tanshinone IIA has been studied extensively in animal models for controlling MIRI. Therefore, we conducted a meta-analysis on the application of tanshinone IIA in rat models with MIRI to evaluate the therapeutic effects of tanshinone IIA.

Methods

A comprehensive search was conducted across PubMed, Web of Science, Embase, the Cochrane Library, the China National Knowledge Infrastructure database, the Wanfang database, and the Chinese Scientific Journal Database to gather studies on tanshinone IIA intervention in rat models with MIRI.We employed SYRCLE's risk of bias tool to assess study quality. The primary outcome indicators were superoxide dismutase (SOD) and malondialdehyde (MDA). Myocardial infarction area was a secondary outcome indicator. This study was registered at PROSPERO (registration number CRD 42022344447).

Results

According to the inclusion and exclusion criteria, 15 eligible studies were selected from 295 initially identified studies. In rat models with MIRI, tanshinone IIA significantly increased SOD levels while reducing MDA levels and myocardial infarction area. Moreover, the duration of myocardial ischemia influenced the effectiveness of tanshinone IIA. However, additional high-quality research studies are needed to establish the efficacy and definitive guidelines for the use of tanshinone IIA. Animal studies demonstrated that tanshinone IIA exerted a significant therapeutic effect when the ischemia duration was less than 40 minutes. Tanshinone IIA was found to be more effective when administered via intravenous, intraperitoneal, and intragastric routes at doses above 5 mg/kg. Additionally, treatment with tanshinone IIA at all stages-prior to myocardial ischemia, after ischemia but before reperfusion, prior to ischemia and after reperfusion, and after reperfusion-showed satisfactory results.

Conclusions

Tanshinone IIA enhanced SOD activity and reduced MDA levels, thereby ameliorating oxidative stress damage during MIRI. Additionally, it reduced the myocardial infarction area, indicating its effectiveness in mitigating MIRI-induced damage in rats and demonstrating a myocardial protective effect. These findings contribute valuable insights for developing MIRI treatment strategies.

Angiography-derived physiological assessment after percutaneous coronary intervention of chronic total occlusions

Scant data exploring potential suboptimal physiological results after angiographic successful percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) are available. Sixty cases of successful CTO-PCI were selected for this retrospective analysis. Post-CTO-PCI angiography-based fractional flow reserve was computed using the Murray-based fractional flow reserve (μFR) software. Vessel-specific μFR, residual trans-stent gradient (TSG) and corrected TSGstent were calculated. In physiological suboptimal results (μFR < 0.90), the virtual pullback pressure gradient (PPG) curves were analyzed to localize the main pressure drop-down and characterize the patterns of residual disease. The virtual pullback pressure gradient index (vPPGi) was then calculated to objectively characterize the predominant pattern of residual disease (diffuse vs focal). The physiological result was suboptimal in 28 cases (46.7%). The main pressure drop was localised proximal to the stent in 2 (7.1%), distal in 17 (60.7%) and intra-stent in 9 cases (32.2%). Intra-stent residual disease was diffuse in 7 cases and mixed in 2. Distal residual disease was characterised by a pure focal pattern in 12 cases, diffuse in 2 and mixed in 3. In the predominant diffuse phenotype (vPPGi < 0.65), we found a higher rate of TSG ≥ 0.04 (61.5% vs 20.0%, p = 0.025) and TSGstent ≥ 0.009 (46.2% vs 20.0%, p = 0.017) while in the dominant focal phenotype poor-quality distal vessel was constantly present. In our cohort, post-CTO-PCI suboptimal physiological result was frequent (46.7%). Predominant focal phenotype was constantly associated with poor-quality distal vessel, while in the predominant diffuse phenotype, the rate of TSG ≥ 0.04 and TSGstent ≥ 0.009 were significantly higher.

The role of physiology in the contemporary management of coronary artery disease

Coronary physiology assessment, including epicardial and microvascular investigations, is a fundamental tool in the contemporary management of patients with coronary artery disease. Coronary revascularisation guided by functional evaluation has demonstrated superiority over angiography-only-guided treatment. In patients with chronic coronary syndrome, revascularisation did not demonstrate prognostic advantage in terms of mortality over optimal medical therapy (OMT). However, revascularisation of coronary stenosis, which induces myocardial ischaemia, has demonstrated better outcome than OMT alone. Pressure wire (PW) or angiography-based longitudinal coronary physiology provides a point-by-point analysis of the vessel to detect the atherosclerotic pattern of coronary disease. A careful evaluation of this disease pattern allows clinicians to choose the appropriate management strategy.Patients with diffuse disease showed a twofold risk of residual angina after percutaneous coronary intervention (PCI) than those with focal disease. Therefore, OMT alone or coronary artery bypass graft might be considered over PCI. In addition, the post-PCI physiological assessment aims to optimise the result revealing residual myocardial ischaemia. Improvement in post-PCI PW or angiography-based functional indices has been associated with better quality of life and reduced risk of cardiac events and residual angina. Therefore, the information obtained from coronary physiology allows for an optimised treatment strategy, which ultimately leads to improve patient's prognosis and quality of life. This review provides an overview of the latest available evidence in the literature regarding the use of functional assessment of epicardial coronary stenosis in different settings in the contemporary patient-tailored management of coronary disease.

Practical Application of Coronary Physiologic Assessment: Asia-Pacific Expert Consensus Document: Part 1

Coronary physiologic assessment is performed to measure coronary pressure, flow, and resistance or their surrogates to enable the selection of appropriate management strategy and its optimization for patients with coronary artery disease. The value of physiologic assessment is supported by a large body of evidence that has led to major recommendations in clinical practice guidelines. This expert consensus document aims to convey practical and balanced recommendations and future perspectives for coronary physiologic assessment for physicians and patients in the Asia-Pacific region based on updated information in the field that including both wire- and image-based physiologic assessment. This is Part 1 of the whole consensus document, which describes the general concept of coronary physiology, as well as practical information on the clinical application of physiologic indices and novel image-based physiologic assessment.

Applied coronary physiology for planning and guidance of percutaneous coronary interventions. A clinical consensus statement from the European Association of Percutaneous Cardiovascular Interventions (EAPCI) of the European Society of Cardiology

The clinical value of fractional flow reserve and non-hyperaemic pressure ratios are well established in determining an indication for percutaneous coronary intervention (PCI) in patients with coronary artery disease (CAD). In addition, over the last 5 years we have witnessed a shift towards the use of physiology to enhance procedural planning, assess post-PCI functional results, and guide PCI optimisation. In this regard, clinical studies have reported compelling data supporting the use of longitudinal vessel analysis, obtained with pressure guidewire pullbacks, to better understand how obstructive CAD contributes to myocardial ischaemia, to establish the likelihood of functionally successful PCI, to identify the presence and location of residual flow-limiting stenoses and to predict long-term outcomes. The introduction of new functional coronary angiography tools, which merge angiographic information with fluid dynamic equations to deliver information equivalent to intracoronary pressure measurements, are now available and potentially also applicable to these endeavours. Furthermore, the ability of longitudinal vessel analysis to predict the functional results of stenting has played an integral role in the evolving field of simulated PCI. Nevertheless, it is important to have an awareness of the value and challenges of physiology-guided PCI in specific clinical and anatomical contexts. The main aim of this European Association of Percutaneous Cardiovascular Interventions clinical consensus statement is to offer up-to-date evidence and expert opinion on the use of applied coronary physiology for procedural PCI planning, disease pattern recognition and post-PCI optimisation.

Coronary Angiography Upgraded by Imaging Post-Processing: Present and Future Directions

Advances in computer technology and image processing now allow us to obtain from angiographic images a large variety of information on coronary physiology without the use of a guide-wire as a diagnostic information equivalent to FFR and iFR but also information allowing for the performance of a real virtual percutaneous coronary intervention (PCI) and finally the ability to obtain information to optimize the results of PCI. With specific software, it is now possible to have a real upgrading of invasive coronary angiography. In this review, we present the different advances in this field and discuss the future perspectives offered by this technology.

QFR-Based Virtual PCI or Conventional Angiography to Guide PCI: The AQVA Trial

BACKGROUND

Post-percutaneous coronary intervention (PCI) quantitative flow ratio (QFR) values ≥0.90 are associated with a low incidence of adverse events.

OBJECTIVES

The AQVA (Angio-based Quantitative Flow Ratio Virtual PCI Versus Conventional Angio-guided PCI in the Achievement of an Optimal Post-PCI QFR) trial aims to test whether a QFR-based virtual percutaneous coronary intervention (PCI) is superior to a conventional angiography-based PCI at obtaining optimal post-PCI QFR results.

METHODS

The AQVA trial is an investigator-initiated, randomized, controlled, parallel-group clinical trial. Three hundred patients (356 study vessels) undergoing PCI were randomized 1:1 to receive either QFR-based virtual PCI or angiography-based PCI (standard of care). The primary outcome was the rate of study vessels with a suboptimal post-PCI QFR value, which was defined as <0.90. Secondary outcomes were procedure duration, stent length/lesion, and stent number/patient.

RESULTS

Overall, 38 (10.7%) study vessels missed the prespecified optimal post-PCI QFR target. The primary outcome occurred significantly more frequently in the angiography-based group (n = 26, 15.1%) compared with the QFR-based virtual PCI group (n = 12 [6.6%]; absolute difference = 8.5%; relative difference = 57%; P = 0.009). The main cause of a suboptimal result in the angiography-based group is the underestimation of a diseased segment outside the stented one. There were no significant differences among secondary endpoints, although stent length/lesion and stent number/patient were numerically lower in the virtual PCI group (P = 0.06 and P = 0.08, respectively), whereas procedure length was higher in the virtual PCI group (P = 0.06).

CONCLUSIONS

The AQVA trial demonstrated the superiority of QFR-based virtual PCI over angiography-based PCI with regard to post-PCI optimal physiological results. Future larger randomized clinical trials that demonstrate the superiority of this approach in terms of clinical outcomes are warranted. (Angio-based Quantitative Flow Ratio Virtual PCI Versus Conventional Angio-guided PCI in the Achievement of an Optimal Post-PCI QFR [AQVA]; NCT04664140).

Clinical Outcome of FFR-Guided Revascularization Strategy of Coronary Lesions: The HALE-BOPP Study

Background

Recently, questions around the efficacy and effectiveness of Fractional Flow Reserve (FFR) have arisen in various clinical settings.

Methods

The Clinical Outcome of FFR-guided Revascularization Strategy of Coronary Lesions (HALE-BOPP) study is an investigator-initiated, multicentre, international prospective study enrolling patients who underwent FFR measurement on at least one vessel. In accordance with the decision-making workflow and treatment, the vessels were classified in three subgroups: (i) angio-revascularized, (ii) FFR-revascularized, (iii) FFR-deferred. The primary endpoint was the occurrence of target vessel failure (TVF, cardiac death, target vessel myocardial infarction and ischemia-driven target vessel revascularization). The analysis was carried out at vessel- and patient-level.

Results

1305 patients with 2422 diseased vessels fulfilled the criteria for the present analysis. Wire-related pitfalls and transient adenosine-related side effects occurred in 0.8% (95% CI: 0.4%-1.4%) and 3.3% (95% CI: 2.5%-4.3%) of cases, respectively. In FFR-deferred vessels, the overall incidence rate of TVF was 0.024 (95% CI: 0.019-0.031) lesion/year. After a median follow-up of 3.6 years, the occurrence of TVF was 6%, 7% and 11.7% in FFR-deferred, FFR-revascularized and angio-revascularized vessels, respectively. Compared to angio-revascularized vessels, FFR-guided vessels (both FFR-revascularized and FFR-deferred vessels) showed a lower TVF incidence rate lesion/year (0.029, 95% CI: 0.024-0.034 vs. 0.049, 95% CI: 0.040-0.061 respectively, p = 0.0001). The result was consistent after correction for confounding factors and across subgroups of clinical interest. The patient-level analysis confirmed the lower occurrence of TVF in negative-FFR vs. positive-FFR subgroups.

Conclusions

In a large prospective observational study, an FFR-based strategy for the deferral of coronary lesions is a reliable and safe tool, associated with good outcomes.

Clinical Trial Registration

NCT03079739.

Angiographic quantitative flow ratio in acute coronary syndrome: beyond a tool to define ischemia-causing stenosis-a literature review

Background and Objective

Numerous studies have demonstrated the safety and effectiveness of physiology-guided coronary revascularization in chronic coronary syndrome, resulting in a high level of guideline recommendation for these patients. However, the application of coronary physiology in acute coronary syndrome (ACS), especially in the acute phase of myocardial infarction, remains challenging. Over the last decade, the number of novel physiological indices derived from the computation of angiography have been developed as alternatives to pressure wire-based fractional flow reserve. Among these angiography-based indices, the quantitative flow ratio (QFR) is undoubtedly the one with the largest amount of data cumulated so far. In this article, we aim to review the related studies that describe efforts to investigate the diagnostic role of QFR and discuss perspectives for its current and future applications in the setting of the ACS.

Methods

A literature search was performed on the electronic databases, including PubMed, Google Scholar and Web of Science covering publications in English up to May 2022.

Key Content and Findings

An emerging body of evidence has validated the diagnostic accuracy of angiography-derived QFR for the assessment of functional severity of coronary stenosis in both acute and chronic coronary syndromes. In parallel, multiple technologies, i.e., QFR-based pullback pressure gradient index, angiography-derived index of microcirculatory resistance and intravascular imaging-based morphofunctional evaluation methods, have been proposed, allowing operators to easily obtained physiological data of micro and macro-circulation, together with atherosclerotic lesion characteristics in catheterization laboratories. More recently, promising results supporting the clinical value of QFR in guiding revascularization and predicting outcomes for ACS patients have been published.

Conclusions

Angiography-based QFR bears the potential of a wider adoption of coronary physiology assessment in the ACS setting due to its quicker and less-invasive nature. However, the current evidence mainly derived from retrospective studies or post-hoc analyses of prospective trials. Future studies are needed to further explore the benefits of QFR-guided revascularization on outcomes in ACS.

Coronary physiology in the catheterisation laboratory: an A to Z practical guide

Coronary revascularisation, either percutaneous or surgical, aims to improve coronary flow and relieve myocardial ischaemia. The decision-making process in patients with coronary artery disease (CAD) remains largely based on invasive coronary angiography (ICA), even though until recently ICA could not assess the functional significance of coronary artery stenoses. Invasive wire-based approaches for physiological evaluations were developed to properly assess the ischaemic relevance of epicardial CAD. Fractional flow reserve (FFR) and later, instantaneous wave-free ratio (iFR), were shown to improve clinical outcomes in several patient subsets when used for coronary revascularisation guidance or deferral and for procedural optimisation of percutaneous coronary intervention (PCI) results. Despite accumulating evidence and positive guideline recommendations, the adoption of invasive physiology has remained quite low, mainly due to technical and economic issues as well as to operator-resistance to change. Coronary image-based computational physiology has been recently developed, with promising results in terms of accuracy and a reduction in computational time, costs, radiation exposure and risks for the patient. Lastly, the integration of intracoronary imaging and physiology allows for individualised PCI treatment, aiming at complete relief of ischaemia through optimised morpho-functional immediate procedural results. Instead of a conventional state-of-the-art review, this A to Z dictionary attempts to provide a practical guide for the application of coronary physiology in the catheterisation laboratory, exploring several methods, their pitfalls, and useful tips and tricks.

Diagnostic performance of quantitative flow ratio versus fractional flow reserve and resting full-cycle ratio in intermediate coronary lesions

BACKGROUND

Quantitative flow ratio (QFR) is a novel angiography-derived index aimed to assess the functional relevance of coronary stenoses without pressure wires and adenosine. Good diagnostic yield with the hyperemic fractional flow reserve (FFR) have been reported, while data on the comparison of QFR to non-hyperemic pressure ratios (NHPR) are scarce.

METHODS

In this retrospective, observational and single-center study with a large population representative of the real practice, we assessed and compared the diagnostic performance of contrast flow (cQFR) and fixed flow (fQFR) QFR against the NHPR resting full-cyle ratio (RFR) using FFR as reference standard.

RESULTS

A total of 626 lesions from 544 patients were investigated. Mean diameter stenosis, FFR, cQFR, fQFR and RFR were 44.8%, 0.842, 0.847, 0.857 and 0.912, respectively. The correlation between cQFR and FFR was stronger (r = 0.830, P < 0.001) compared to that between FFR and RFR (r = 0.777, P < 0.001) and between cQFR and RFR (r = 0.687, P < 0.001). Using FFR ≤0.80 as reference, the sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy for cQFR were 82%, 95%, 87%, 92%, and 91%, respectively. cQFR displayed a higher area under the curve (AUC) than fQFR and RFR (0.938 vs. 0.891 vs. 0.869, P < 0.01). The good diagnostic yield of cQFR appeared to be maintained in different clinical subsets including female gender, aortic valve stenosis and atrial fibrillation, and in different anatomical subsets including focal and non-focal lesions.

CONCLUSION

cQFR has a high and better diagnostic performance than the NHPR RFR in predicting FFR-based functional significance of coronary stenoses.

Impact of trans-stent gradient on outcome after PCI: results from a HAWKEYE substudy

To test whether quantitative flow ratio (QFR)-based trans-stent gradient (TSG) is associated with adverse clinical events at follow-up. A post-hoc analysis of the multi-center HAWKEYE study was performed. Vessels post-PCI were divided into four groups (G) as follows: G1: QFR ≥ 0.90 TSG = 0 (n = 412, 54.8%); G2: QFR ≥ 0.90, TSG > 0 (n = 216, 28.7%); G3: QFR < 0.90, TSG = 0 (n = 37, 4.9%); G4: QFR < 0.90, TSG > 0 (n = 86, 11.4%). Cox proportional hazards regression model was used to analyze the effect of baseline and prognostic variables. The final reduced model was obtained by backward stepwise variable selection. Receiver operating characteristic (ROC) was plotted and area under the curve (AUC) was calculated and reported. Overall, 449 (59.8%) vessels had a TSG = 0 whereas (40.2%) had TSG > 0. Ten (2.2%) vessel-oriented composite endpoint (VOCE) occurred in vessels with TSG = 0, compared with 43 (14%) in vessels with TSG > 0 (p < 0.01). ROC analysis showed an AUC of 0.74 (95% CI: 0.67 to 0.80; p < 0.001). TSG > 0 was an independent predictor of the VOCE (HR 2.95 [95% CI 1.77–4.91]). The combination of higher TSG and lower final QFR (G4) showed the worst long-term outcome while low TSG and high QFR showed the best outcome (G1) while either high TSG or low QFR (G2, G3) showed intermediate and comparable outcomes. Higher trans-stent gradient was an independent predictor of adverse events and identified a subgroup of patients at higher risk for poor outcomes even when vessel QFR was optimal (> 0.90).

Prognostic Implications of Quantitative Flow Ratio-Derived Physiological 2-Dimensional Residual Disease Patterns After Stenting

BACKGROUND

Post-percutaneous coronary intervention (PCI) residual disease is associated with clinical outcomes. Nevertheless, the prognostic value of residual disease patterns remains unknown.

OBJECTIVES

This study aimed to evaluate clinical implications of 2-dimensional residual disease patterns after PCI.

METHODS

One thousand six hundred seven vessels that underwent successful PCI were included. Two-dimensional residual disease patterns were determined by visual assessment or the quantitative flow ratio (QFR)-derived pull back pressure gradient index (with a cutoff value of 0.78 to define predominant focal versus diffuse disease) and instantaneous QFR gradient per unit length (with a cutoff value of ≥0.005/mm to define a major gradient). The clinical outcome was the 2-year vessel-oriented composite outcome (VOCO).

RESULTS

Residual disease patterns were classified into 4 groups: predominant focal without and with a major gradient (group 1 [n = 1,058] and group 2 [n = 63], respectively) and predominant diffuse without and with a major gradient (group 3 [n = 318] and group 4 [n = 168], respectively). At 2 years, VOCO was lowest in group 1 (1.4% vs 5.4% in group 2 vs 4.8% in group 3 vs 8.5% in group 4, all P < 0.05), whereas there was no prognostic value for classifications by visual assessment. Physiological residual disease patterns were independently associated with VOCO and showed increased prognostic value when introduced to a model with clinical risk factors only (C index: 0.77 vs. 0.68, P = 0.008; net reclassification improvement: 0.65, P < 0.001; integrated discrimination improvement: 0.020, P < 0.001).

CONCLUSIONS

Objective analysis of post-PCI QFR pull backs using the concept of 2-dimensional residual disease patterns is feasible and superior to visual assessments. The residual disease patterns were independently associated with VOCO at 2 years.

Angiography-Based Fractional Flow Reserve: State of the Art

Purpose of Review

Three-dimensional quantitative coronary angiography-based methods of fractional flow reserve (FFR) derivation have emerged as an appealing alternative to conventional pressure-wire-based physiological lesion assessment and have the potential to further extend the use of physiology in general. Here, we summarize the current evidence related to angiography-based FFR and perspectives on future developments.

Recent Findings

Growing evidence suggests good diagnostic performance of angiography-based FFR measurements, both in chronic and acute coronary syndromes, as well as in specific lesion subsets, such as long and calcified lesions, left main coronary stenosis, and bifurcations. More recently, promising results on the superiority of angiography-based FFR as compared to angiography-guided PCI have been published.

Summary

Currently available angiography -FFR indices proved to be an excellent alternative to invasive pressure wire-based FFR. Dedicated prospective outcome data comparing these indices to routine guideline recommended PCI including the use of FFR are eagerly awaited.

Comparison of Resting Full-Cycle Ratio and Fractional Flow Reserve in a German Real-World Cohort

Objective: The aim of this study was to evaluate non-hyperemic resting pressure ratios (NHPRs), especially the novel “resting full-cycle ratio” (RFR; lowest pressure distal to the stenosis/aortic pressure during the entire cardiac cycle), compared to the gold standard fractional flow reserve (FFR) in a “real-world” setting.

Methods: The study included patients undergoing coronary pressure wire studies at one German University Hospital. No patients were excluded based on any baseline or procedural characteristics, except for insufficient quality of traces. The diagnostic performance of four NHPRs vs. FFR ≤ 0.80 was tested. Morphological characteristics of stenoses were analyzed by quantitative coronary angiography.

Results: 617 patients with 712 coronary lesions were included. RFR showed a significant correlation with FFR (r = 0.766, p < 0.01). Diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of RFR were 78% (95% confidence interval = 75; 81), 72% (65; 78), 81% (77; 84), 63% (57; 69), and 86% (83; 89). Relevant predictors for discordance of RFR ≤ 0.89/FFR > 0.8 were LAD lesions, peripheral artery disease, age, female sex and non-focal stenoses. Predictors for discordance of RFR > 0.89/FFR ≤ 0.8 included non-LCX lesions, percent diameter stenosis and previous percutaneous coronary intervention in the target vessel. RFR and all other NHPRs were highly correlated with each other.

Conclusion: All NHPRs have a similar correlation with the gold standard FFR and may facilitate the acceptance and implementation of physiological assessments of lesion severity. However, we found ~20% discordant results between NHPRs and FFR in our “all-comers” German cohort.

Comparison of Clinically Adjudicated Versus Flow-Based Adjudication of Revascularization Events in Randomized Controlled Trials

BACKGROUND

In clinical trials, the optimal method of adjudicating revascularization events as clinically or nonclinically indicated (CI) is to use an independent Clinical Events Committee (CEC). However, the Academic Research Consortium-2 currently recommends using physiological assessment. The level of agreement between these methods of adjudication remains unknown.

METHODS

Data for all CEC adjudicated revascularization events among the 3457 patients followed-up for 2-years in the TALENT trial, and 3-years in the DESSOLVE III, PIONEER, and SYNTAX II trial were collected and readjudicated according to a quantitative flow ratio (QFR) analysis of the revascularized vessels, by an independent core lab blinded to the results of the conventional CEC adjudication. The κ statistic was used to assess the level of agreement between the 2 methods.

RESULTS

In total, 351 CEC-adjudicated repeat revascularization events occurred, with retrospective QFR analysis successfully performed in 212 (60.4%). According to QFR analysis, 104 events (QFR ≤0.80) were adjudicated as CI revascularizations and 108 (QFR >0.80) were not. The agreement between CEC and QFR based adjudication was just fair (κ=0.335). Between the 2 methods of adjudication, there was a disagreement of 26.4% and 7.1% in CI and non-CI revascularization, respectively. Overall, the concordance and discordance rates were 66.5% and 33.5%, respectively.

CONCLUSIONS

In this event-level analysis, QFR based adjudication had a relatively low agreement with CEC adjudication with respect to whether revascularization events were CI or not. CEC adjudication appears to overestimate CI revascularization as compared with QFR adjudication. Direct comparison between these 2 strategies in terms of revascularization adjudication is warranted in future trials. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: TALENT trial: NCT02870140, DESSOLVE III trial: NCT02385279, SYNTAX II: NCT02015832, and PIONEER trial: NCT02236975.

Angiography-based estimation of coronary physiology: A frame is worth a thousand words

Cumulative evidence has shown that coronary revascularization should be guided by functional significance of coronary lesions. Fractional flow reserve (FFR) is the gold standard for assessment of hemodynamic significance of coronary stenosis and FFR-guided percutaneous coronary intervention has improved clinical outcomes in patients with coronary artery disease. However, limitations of FFR such as increased operational time and cost, requirement of pressure wire and adenosine and technical difficulties have led to significant underutilization of the method in clinical practice. In the last few years, several methods of FFR estimation based on coronary angiography images have emerged to overcome invasive FFR limitations. The common elements of the novel indices include a 3D anatomical reconstruction of coronary vessels by angiographic projections and various approaches to fluid dynamics computation. Angiography-derived FFR methods have shown high diagnostic accuracy compared to invasive FFR. Although there are promising results regarding their prognostic role, large randomized trials evaluating clinical outcomes are lacking. The aim of this review is to present currently available angiography-derived FFR indices and highlight their differences, advantages, disadvantages and potential clinical implications.