Fractional Flow Reserve in Unstable Angina and Non–ST-Segment Elevation Myocardial Infarction

Clinical Updates in Coronary Artery Disease: A Comprehensive Review

Despite significant goals achieved in diagnosis and treatment in recent decades, coronary artery disease (CAD) remains a high mortality entity and continues to pose substantial challenges to healthcare systems globally. After the latest guidelines, novel data have emerged and have not been yet considered for routine practice. The scope of this review is to go beyond the guidelines, providing insights into the most recent clinical updates in CAD, focusing on non-invasive diagnostic techniques, risk stratification, medical management and interventional therapies in the acute and stable scenarios. Highlighting and synthesizing the latest developments in these areas, this review aims to contribute to the understanding and management of CAD helping healthcare providers worldwide.

Contemporary Use of Coronary Physiology in Cardiology

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. Nevertheless, the role of coronary physiology testing is less clear among certain patients' groups, including patients with serial coronary lesions, acute coronary syndromes, aortic stenosis, heart failure, as well as post-percutaneous coronary interventions. In this review, we aimed to discuss the utility and clinical evidence of coronary physiology (mainly FFR and iFR), with emphasis on those specific patient groups.

Practical Application of Coronary Physiologic Assessment: Asia-Pacific Expert Consensus Document: Part 2

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 clinical data that has led to major recommendations in all 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 includes both wire- and image-based physiologic assessment. This is Part 2 of the whole consensus document, which provides theoretical and practical information on physiologic indexes for specific clinical conditions and patient statuses.

Diagnostic performance of quantitative flow ratio in non-ST elevation acute coronary syndromes in comparison to non-hyperemic pressure ratios: a prospective study

Quantitative flow ratio (QFR) is a new angiography-based coronary physiology tool aimed to evaluate functional relevance of intermediate coronary lesions. Aim of the study is to assess diagnostic performance of QFR in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) in comparison to currently used non-hyperaemic pressure ratios (NHPRs). In this prospective, single-centre study, coronary physiology of intermediate coronary stenoses of non-culprit vessels in patients presenting with NSTE-ACS was evaluated using NHPRs (iFR, DFR or RFR). Subsequently, QFR was computed offline by a QFR analyst blinded to the NHPR results. Diagnostic performance of QFR was assessed in comparison to NHPRs as reference standard. A total of 60 vessels with intermediate coronary stenoses was investigated. The NHPRs were used as follows: RFR 38%, DFR 47% and iFR 15% of the cases. The NHPR result was positive, showing significant lesion, in 19 cases. A significant correlation was found between NHPR and QFR (r = 0.84, p < 0.001). Classification agreement of the two methods (95%) and diagnostic performance of QFR in comparison to NHPR (AUC: 0.962 [0.914-1.00]) were both high. Sensitivity, specificity, positive and negative predictive value of QFR in comparison to NHPR were 84.2%, 100%, 100% and 93.2% respectively. QFR has high diagnostic performance in detecting functionally significant lesions of non-culprit arteries in patients with NSTE-ACS and multivessel disease. Due to its high negative predictive value, it can be used to safely avoid unnecessary invasive physiological assessment of these lesions.

Fractional Flow Reserve-Negative High-Risk Plaques and Clinical Outcomes After Myocardial Infarction

Importance

Even after fractional flow reserve (FFR)-guided complete revascularization, patients with myocardial infarction (MI) have high rates of recurrent major adverse cardiovascular events (MACE). These recurrences may be caused by FFR-negative high-risk nonculprit lesions.

Objective

To assess the association between optical coherence tomography (OCT)-identified high-risk plaques of FFR-negative nonculprit lesions and occurrence of MACE in patients with MI.

Design, Setting, and Participants

PECTUS-obs (Identification of Risk Factors for Acute Coronary Events by OCT After STEMI [ST-segment elevation MI] and NSTEMI [non-STEMI] in Patients With Residual Non-flow Limiting Lesions) is an international, multicenter, prospective, observational cohort study. In patients presenting with MI, OCT was performed on all FFR-negative (FFR > 0.80) nonculprit lesions. A high-risk plaque was defined containing at least 2 of the following prespecified criteria: (1) a lipid arc at least 90°, (2) a fibrous cap thickness less than 65 μm, and (3) either plaque rupture or thrombus presence. Patients were enrolled from December 14, 2018, to September 15, 2020. Data were analyzed from December 2, 2022, to June 28, 2023.

Main Outcome and Measure

The primary end point of MACE, a composite of all-cause mortality, nonfatal MI, or unplanned revascularization, at 2-year follow-up was compared in patients with and without a high-risk plaque.

Results

A total of 438 patients were enrolled, and OCT findings were analyzable in 420. Among included patients, mean (SD) age was 63 (10) years, 340 (81.0) were men, and STEMI and non-STEMI were equally represented (217 [51.7%] and 203 [48.3%]). A mean (SD) of 1.17 (0.42) nonculprit lesions per patient was imaged. Analysis of OCT images revealed at least 1 high-risk plaque in 143 patients (34.0%). The primary end point occurred in 22 patients (15.4%) with a high-risk plaque and 23 of 277 patients (8.3%) without a high-risk plaque (hazard ratio, 1.93 [95% CI, 1.08-3.47]; P = .02), primarily driven by more unplanned revascularizations in patients with a high-risk plaque (14 of 143 [9.8%] vs 12 of 277 [4.3%]; P = .02).

Conclusions and Relevance

Among patients with MI and FFR-negative nonculprit lesions, the presence of a high-risk plaque is associated with a worse clinical outcome, which is mainly driven by a higher number of unplanned revascularizations. In a population with a high recurrent event rate despite physiology-guided complete revascularization, these results call for research on additional pharmacological or focal treatment strategies in patients harboring high-risk plaques.

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.

Multimodality OCT, IVUS and FFR evaluation of coronary intermediate grade lesions in women vs. men

Background

The pathophysiology of atherosclerotic plaque formation and its vulnerability seem to differ between genders due to contrasting risk profiles and sex hormones, however this process is still insufficiently understood. The aim of the study was to compare the differences between sexes regarding the optical coherence tomography (OCT), intravascular ultrasound (IVUS) and fractional flow reserve (FFR)-derived coronary plaque indices.

Methods

In this single-center multimodality imaging study patients with intermediate grade coronary stenoses identified in coronary angiogram (CAG) were evaluated using OCT, IVUS and FFR. Stenoses were considered significant when the FFR value was ≤0.8. Minimal lumen area (MLA), was analyzed by OCT in addition to plaque stratification into fibrotic, calcific, lipidic and thin-cap fibroatheroma (TCFA). IVUS was used for evaluation of lumen-, plaque- and vessel volume, as well as plaque burden.

Results

A total of 112 patients (88 men and 24 women) with chronic coronary syndromes (CCS), who underwent CAG were enrolled. No significant differences in baseline characteristics were present between the study groups. The mean FFR was 0.76 (0.73-0.86) in women and 0.78 ± 0.12 in men (p = 0.695). OCT evaluation showed a higher prevalence of calcific plaques among women than men p = 0.002 whereas lipid plaques were more frequent in men (p = 0.04). No significant differences regarding minimal lumen diameter and minimal lumen area were found between the sexes. In IVUS analysis women presented with significantly smaller vessel area, plaque area, plaque volume, vessel volume (11.1 ± 3.3 mm² vs. 15.0 ± 4.6 mm² p = 0.001, 6.04 ± 1.7 mm² vs. 9.24 ± 2.89 mm² p < 0.001, 59.8 ± 35.2 mm³ vs. 96.3 (52.5-159.1) mm³ p = 0.005, 106.9 ± 59.8 mm³ vs. 153.3 (103-253.4) mm³ p = 0.015 respectively). At MLA site plaque burden was significantly greater for men than women (61.50 ± 7.7% vs. 55.5 ± 8.0% p = 0.005). Survival did not differ significantly between women and men (94.6 ± 41.9 months and 103.51 ± 36.7 months respectively; p = 0.187).

Conclusion

The presented study did not demonstrate significant differences in FFR values between women and men, yet a higher prevalence of calcific plaques by OCT and lower plaque burden at the MLA site by IVUS was found in women vs. men.

Acute coronary syndromes and multivessel coronary artery disease

Patients with acute coronary syndromes (ACS) and multivessel coronary artery disease are frequently encountered during clinical practice and those patients are at higher risk of subsequent acute cardiovascular events. In patients presenting with both ST-segment elevation myocardial infarction and non-ST-segment elevation acute coronary syndromes, complete revascularization is associated with decreased risk of major adverse cardiovascular events. Nevertheless, the optimal timing of the intervention and treatment modality are still in discussions. Furthermore, non-culprit lesions assessment based on stenosis severity, either on visual or on functional evaluation, may not provide information about vulnerable plaques prone to thrombosis. Therefore, insights from intracoronary imaging could further identify high-risk plaque and patients at higher risk of future adverse events. This article aims to provide an overview of current guideline recommendations, envisioning future perspectives for the treatment of patients with ACS and multivessel disease.

Prognostic impact of fractional flow reserve measurements in patients with acute coronary syndromes: a subanalysis of the FLORIDA study

Randomized trials suggest benefits for fractional flow reserve (FFR)-guided vs. angiography-guided treatment strategies in well-defined and selected patient cohorts with acute coronary syndromes (ACS). The long-term prognostic value of FFR measurement in unselected all-comer ACS patients, however, remains unknown. This subanalysis of the Fractional FLOw Reserve In cardiovascular DiseAses (FLORIDA) study sought to investigate the long-term effects of FFR in the management of lesions in patients with acute coronary syndrome (ACS). FLORIDA was an observational all-comer cohort study performed in Germany, that was population-based and unselected. Patients enrolled into the anonymized InGef Research Database presenting with ACS and undergoing coronary angiography between January 2014 and December 2015 were included in the analysis. Patients were stratified into either the FFR-guided or the angiography-guided treatment arm, based on the treatment received. A matched cohort study design was used. The primary endpoint was all-cause mortality. The secondary endpoint was major adverse cardiovascular events (MACE), a composite of death, non-fatal myocardial infarction (MI), and repeat revascularization. Follow-up time was 3 years. Rates of 3-year mortality were 10.2 and 14.0% in the FFR-guided and the angiography-guided treatment arms (p = 0.04), corresponding to a 27% relative risk reduction for FFR in ACS patients. Rates of MACE were similar in both arms (47.7 vs. 51.5%, p = 0.14), including similar rates of non-fatal MI (27.7 vs. 25.4%, p = 0.47) and revascularization (9.9 vs. 12.1%, p = 0.17). In this large, all-comer observational study of ACS patients, FFR-guided revascularization was associated with a lower mortality at 3 years. This finding encourages the routine use of FFR to guide lesion revascularization in patients presenting with ACS.

Fractional flow reserve and non-hyperemic indices: Essential tools for percutaneous coronary interventions

Hemodynamical evaluation of a coronary artery lesion is an important diagnostic step to assess its functional impact. Fractional flow reserve (FFR) received a class IA recommendation from the European Society of Cardiology for the assessment of angiographically moderate stenosis. FFR evaluation of coronary artery disease offers improvement of the therapeutic strategy, deferring unnecessary procedures for lesions with a FFR > 0.8, improving patients' management and clinical outcome. Post intervention, an optimal FFR > 0.9 post stenting should be reached and > 0.8 post drug eluting balloons. Non-hyperemic pressure ratio measurements have been validated in previous studies with a common threshold of 0.89. They might overestimate the hemodynamic significance of some lesions but remain useful whenever hyperemic agents are contraindicated. FFR remains the gold standard reference for invasive assessment of ischemia. We illustrate this review with two cases introducing the possibility to estimate also non-invasively FFR from reconstructed 3-D angiograms by quantitative flow ratio. We conclude introducing a hybrid approach to intermediate lesions (DFR 0.85-0.95) potentially maximizing clinical decision from all measurements.

Fractional flow reserve versus angiography-guided strategy in acute myocardial infarction with multivessel disease: a randomized trial

AIMS

In patients with acute myocardial infarction (MI) and multivessel coronary artery disease, percutaneous coronary intervention (PCI) of non-infarct-related artery reduces death or MI. However, whether selective PCI guided by fractional flow reserve (FFR) is superior to routine PCI guided by angiography alone is unclear. The current trial sought to compare FFR-guided PCI with angiography-guided PCI for non-infarct-related artery lesions among patients with acute MI and multivessel disease.

METHODS AND RESULTS

Patients with acute MI and multivessel coronary artery disease who had undergone successful PCI of the infarct-related artery were randomly assigned to either FFR-guided PCI (FFR ≤0.80) or angiography-guided PCI (diameter stenosis of >50%) for non-infarct-related artery lesions. The primary end point was a composite of time to death, MI, or repeat revascularization. A total of 562 patients underwent randomization. Among them, 60.0% underwent immediate PCI for non-infarct-related artery lesions and 40.0% were treated by a staged procedure during the same hospitalization. PCI was performed for non-infarct-related artery in 64.1% in the FFR-guided PCI group and 97.1% in the angiography-guided PCI group, and resulted in significantly fewer stent used in the FFR-guided PCI group (2.2 ± 1.1 vs. 2.5 ± 0.9, P < 0.001). At a median follow-up of 3.5 years (interquartile range: 2.7-4.1 years), the primary end point occurred in 18 patients of 284 patients in the FFR-guided PCI group and in 40 of 278 patients in the angiography-guided PCI group (7.4% vs. 19.7%; hazard ratio, 0.43; 95% confidence interval, 0.25-0.75; P = 0.003). The death occurred in five patients (2.1%) in the FFR-guided PCI group and in 16 patients (8.5%) in the angiography-guided PCI group; MI in seven (2.5%) and 21 (8.9%), respectively; and unplanned revascularization in 10 (4.3%) and 16 (9.0%), respectively.

CONCLUSION

In patients with acute MI and multivessel coronary artery disease, a strategy of selective PCI using FFR-guided decision-making was superior to a strategy of routine PCI based on angiographic diameter stenosis for treatment of non-infarct-related artery lesions regarding the risk of death, MI, or repeat revascularization.

Risk Stratification in Acute Coronary Syndrome by Comprehensive Morphofunctional Assessment With Optical Coherence Tomography

Background

Artificial intelligence enables simultaneous evaluation of plaque morphology and computational physiology from optical coherence tomography (OCT).

Objectives

This study sought to appraise the predictive value of major adverse cardiovascular events (MACE) by combined plaque morphology and computational physiology.

Methods

A total of 604 patients with acute coronary syndrome who underwent OCT imaging in ≥1 nonculprit vessel during index coronary angiography were retrospectively enrolled. A novel morphologic index, named the lipid-to-cap ratio (LCR), and a functional parameter to evaluate the physiologic significance of coronary stenosis from OCT, namely, the optical flow ratio (OFR), were calculated from OCT, together with classical morphologic parameters, like thin-cap fibroatheroma (TCFA) and minimal lumen area.

Results

The 2-year cumulative incidence of a composite of nonculprit vessel–related cardiac death, cardiac arrest, acute myocardial infarction, and ischemia-driven revascularization (NCV-MACE) at 2 years was 4.3%. Both LCR (area under the curve [AUC]: 0.826; 95% CI: 0.793-0.855) and OFR (AUC: 0.838; 95% CI: 0.806-0.866) were superior to minimal lumen area (AUC: 0.618; 95% CI: 0.578-0.657) in predicting NCV-MACE at 2 years. Patients with both an LCR of >0.33 and an OFR of ≤0.84 had significantly higher risk of NCV-MACE at 2 years than patients in whom at least 1 of these 2 parameters was normal (HR: 42.73; 95% CI: 12.80-142.60; P < 0.001). The combination of thin-cap fibroatheroma and OFR also identified patients at higher risk of future events (HR: 6.58; 95% CI: 2.83-15.33; P < 0.001).

Conclusions

The combination of LCR with OFR permits the identification of a subgroup of patients with 43-fold higher risk of recurrent cardiovascular events in the nonculprit vessels after acute coronary syndrome.

Clinical use of physiological lesion assessment using pressure guidewires: an expert consensus document of the Japanese association of cardiovascular intervention and therapeutics-update 2022

Fractional flow reserve and instantaneous wave-free ratio are widely accepted and recommended in Western and Japanese guidelines for appropriate percutaneous coronary intervention. There are, however, many differences in clinical situations between Japan and Western countries. Therefore, the Task Force on coronary physiology of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has proposed an expert consensus document to summarize current evidence and suggest the practical use of physiological lesion assessment in Japan.

The Full Revasc (Ffr-gUidance for compLete non-cuLprit REVASCularization) Registry-based randomized clinical trial

BACKGROUND

Complete revascularization in ST elevation myocardial infarction (STEMI) patients with multivessel disease has resulted in reduction in composite clinical endpoints in medium sized trials. Only one trial showed an effect on hard clinical endpoints, but the revascularization procedure was guided by angiographic evaluation of stenosis severity. Consequently, it is not clear how Fractional Flow Reserve (FFR)-guided percutaneous coronary intervention (PCI) affects hard clinical endpoints in STEMI.

METHODS AND RESULTS

The Ffr-gUidance for compLete non-cuLprit REVASCularization (FULL REVASC) - is a pragmatic, multicenter, international, registry-based randomized clinical trial designed to evaluate whether a strategy of FFR-guided complete revascularization of non-culprit lesions, reduces the combined primary endpoint of total mortality, non-fatal MI and unplanned revascularization. 1,545 patients were randomized to receive FFR-guided PCI during the index hospitalization or initial conservative management of non-culprit lesions. We found that in angiographically severe non-culprit lesions of 90-99% severity, 1 in 5 of these lesions were re-classified as non-flow limiting by FFR. Considering lesions of intermediate severity (70%-89%), half were re-classified as non-flow limiting by FFR. The study is event driven for an estimated follow-up of at least 2.75 years to detect a 9.9%/year>7.425%/year difference (HR = 0.74 at 80% power (α = .05)) for the combined primary endpoint.

CONCLUSION

This large randomized clinical trial is designed and powered to evaluate the effect of complete revascularization with FFR-guided PCI during index hospitalization on total mortality, non-fatal MI and unplanned revascularization following primary PCI in STEMI patients with multivessel disease. Enrollment completed in September 2019 and follow-up is ongoing.

Validation of novel 3-dimensional quantitative coronary angiography based software to calculate fractional flow reserve post stenting

OBJECTIVES

To validate novel dedicated 3D-QCA based on the software to calculate post PCI vessel-FFR (vFFR) in a consecutive series of patients, to assess the diagnostic accuracy, and to assess inter-observer variability.

BACKGROUND

Low post percutaneous coronary intervention (PCI) fractional flow reserve (FFR) predicts future adverse cardiac events. However, FFR assessment requires the insertion of a pressure wire in combination with the use of a hyperemic agent.

METHODS

FAST POST study is an observational, retrospective, single-center cohort study. One hundred patients presenting with stable angina or non ST-elevation myocardial infarction, who underwent post PCI FFR assessment using a dedicated microcatheter were included. Two orthogonal angiographic projections were acquired to create a 3D reconstruction of the coronary artery using the CAAS workstation 8.0. vFFR was subsequently calculated using the aortic root pressure.

RESULTS

Mean age was 65±12 years and 70% were male. Mean microcatheter based FFR and vFFR were 0.91±0.07 and 0.91±0.06, respectively. A good linear correlation was found between FFR and vFFR (r = 0.88; p <.001). vFFR had a higher accuracy in the identification of patients with FFR values <0.90, AUC 0.98 (95% CI: 0.96-1.00) as compared with 3D-QCA AUC 0.62 (95% CI: 0.94-0.74). Assessment of vFFR had a low inter-observer variability (r = 0.95; p <.001).

CONCLUSION

3D-QCA derived post PCI vFFR correlates well with invasively measured microcatheter based FFR and has a high diagnostic accuracy to detect FFR <0.90 with low inter-observer variability.

Compared Outcomes of ST-Elevation Myocardial Infarction Patients with Multivessel Disease Treated with Primary Percutaneous Coronary Intervention and Preserved Fractional Flow Reserve of Non-Culprit Lesions Treated Conservatively and of Those with Low Fractional Flow Reserve Managed Invasively: Insights from the FLOWER MI trial

Background: In patients with ST-elevation myocardial infarction (STEMI) and multivessel disease, percutaneous coronary intervention (PCI) for non-culprit lesions guided by FFR is superior to treatment of the culprit lesion alone. Whether deferring non-culprit PCI is safe in this specific context is questionable. We aimed to assess clinical outcomes at one-year in STEMI patients with multivessel coronary artery disease and an FFR-guided strategy for non-culprit lesions, according to whether or not ≥1 PCI was performed. Methods: Outcomes were analyzed in patients of the randomized FLOWER MI (Flow Evaluation to Guide Revascularization in Multivessel ST-Elevation Myocardial Infarction) trial in whom, after successful primary PCI, non-culprit lesions were assessed using FFR. The primary outcome was a composite of all-cause death, non-fatal MI, and unplanned hospitalization with urgent revascularization at one year. Results: Among 1,171 patients enrolled in this study, 586 were assigned to the FFR-guided group: 388 (66%) of them had ≥1 PCI and 198 (34%) had no PCI. Mean FFR before decision (i.e., PCI or not) of non-culprit lesions were 0.75±0.10 and 0.88±0.06, respectively. During follow-up, a primary outcome event occurred in 16 of 388 patients (4.1%) in patients with PCI and in 16 of 198 patients (8.1%) in patients without PCI (adjusted hazard ratio, 0.42; 95% confidence interval, 0.20 to 0.88; P = 0.02). Conclusions: In patients with STEMI undergoing complete revascularization guided by FFR measurement, those with ≥1 PCI had lower event rates at 1 year, compared with patients with deferred PCI, suggesting that deferring lesions judged relevant by visual estimation but with FFR >0.80 may not be optimal in this context. Future randomized studies are needed to confirm this data.

Identification of anatomic risk factors for acute coronary events by optical coherence tomography in patients with myocardial infarction and residual nonflow limiting lesions: rationale and design of the PECTUS-obs study

INTRODUCTION

In patients with myocardial infarction, the decision to treat a nonculprit lesion is generally based on its physiological significance. However, deferral of revascularisation based on nonischaemic fractional flow reserve (FFR) values in these patients results in less favourable outcomes compared with patients with stable coronary artery disease, potentially caused by vulnerable nonculprit lesions. Intravascular optical coherence tomography (OCT) imaging allows for in vivo morphological assessment of plaque 'vulnerability' and might aid in the detection of FFR-negative lesions at high risk for recurrent events.

METHODS AND ANALYSIS

The PECTUS-obs study is an international multicentre prospective observational study that aims to relate OCT-derived vulnerable plaque characteristics of nonflow limiting, nonculprit lesions to clinical outcome in patients with myocardial infarction. A total of 438 patients presenting with myocardial infarction (ST-elevation myocardial infarction and non-ST-elevation myocardial infarction) will undergo OCT-imaging of any FFR-negative nonculprit lesion for detection of plaque vulnerability. The primary study endpoint is a composite of major adverse cardiovascular events (all-cause mortality, nonfatal myocardial infarction or unplanned revascularisation) at 2-year follow-up. Secondary endpoints will be the same composite at 1-year and 5-year follow-up, target vessel failure, target vessel revascularisation, target lesion failure and target lesion revascularisation.

ETHICS AND DISSEMINATION

This study has been approved by the Medical Ethics Committee of the region Arnhem-Nijmegen. The results of this study will be disseminated in a main paper and additional papers with subgroup analyses.

TRIAL REGISTRATION NUMBER

NCT03857971.

Functional Assessment of Coronary Artery Lesions-Old and New Kids on the Block

Angiography is inaccurate in assessing functional significance of coronary lesions, and often stenoses deemed severe on angiographic assessment do not restrict coronary blood flow at rest or with maximal dilatation. Angiography-guided revascularization has not shown improvement in hard clinical outcomes in stable ischemic heart disease (SIHD). Most current guidelines for SIHD recommend invasive functional assessment of lesions to guide revascularization if prior evidence of ischemia is not available. There has been several recent advances and development of novel methods in this arena. Various contemporary clinical trials have been undertaken for validation of these indices. Here we review the physiological basis, tools, techniques, and evidence base for various invasive (resting as well as hyperemic) and noninvasive methods for functional assessment of coronary lesions. Left main stenosis, bifurcation lesions, serial stenosis, and acute coronary syndrome each causes unique disequilibrium that may affect measurements and require special considerations for accurate functional assessment.

Virtual (Computed) Fractional Flow Reserve: Future Role in Acute Coronary Syndromes

The current management of acute coronary syndromes (ACS) is with an invasive strategy to guide treatment. However, identifying the lesions which are physiologically significant can be challenging. Non-invasive imaging is generally not appropriate or timely in the acute setting, so the decision is generally based upon visual assessment of the angiogram, supplemented in a small minority by invasive pressure wire studies using fractional flow reserve (FFR) or related indices. Whilst pressure wire usage is slowly increasing, it is not feasible in many vessels, patients and situations. Limited evidence for the use of FFR in non-ST elevation (NSTE) ACS suggests a 25% change in management, compared with traditional assessment, with a shift from more to less extensive revascularisation. Virtual (computed) FFR (vFFR), which uses a 3D model of the coronary arteries constructed from the invasive angiogram, and application of the physical laws of fluid flow, has the potential to be used more widely in this situation. It is less invasive, fast and can be integrated into catheter laboratory software. For severe lesions, or mild disease, it is probably not required, but it could improve the management of moderate disease in 'real time' for patients with non-ST elevation acute coronary syndromes (NSTE-ACS), and in bystander disease in ST elevation myocardial infarction. Its practicability and impact in the acute setting need to be tested, but the underpinning science and potential benefits for rapid and streamlined decision-making are enticing.

A case of mild-to-intermediate left-main lesion with high-risk plaque features: "Blindness of physiology" for PCI guidance?

In patients presenting with acute coronary syndrome without ST elevation, both FFR and OCT imaging may be necessary to adequately interrogate patients with intermediate and ambiguous left-main coronary stenosis.

The management of non-culprit coronary lesions in patients with acute coronary syndrome

About 50% of patients diagnosed with ST-segment elevation myocardial infarction have multivessel disease on coronary angiography. Recent evidence has shown that a staged percutaneous coronary intervention (PCI) strategy of non-culprit lesions, achieving complete revascularization, significantly reduces the rate of recurrent cardiovascular events compared with a PCI strategy limited to culprit lesion. Although functional evaluation of intermediate coronary stenoses by functional flow reserve (FFR) or instantaneous wave-free ratio (iFR) is widely used to detect residual myocardial ischaemia, the reliability of the study of non-culprit lesions in the acute phase of heart attack is controversial. On the other hand, the excess of new events in patients with acute coronary syndrome in whom PCI was deferred on the basis of FFR/iFR compared to patients with stable CAD could be due to both an inadequate functional evaluation and an intrinsic higher risk, related to the presence of untreated vulnerable plaques. In this context, intra-coronary imaging has shown that the presence of vulnerability features in non-culprit plaques is associated with an increased rate of ischaemic recurrence.

Diagnostic analysis of new quantitative parameters of low-dose dynamic myocardial perfusion imaging with CZT SPECT in the detection of suspected or known coronary artery disease

The goal of this study is to explore and evaluate the diagnostic values of myocardial blood flow (MBF), myocardial flow reserve (MFR) and relative flow reserve (RFR) obtained with low-dose dynamic CZT SPECT for patients with suspected or known coronary artery disease (CAD). Fifty-seven consecutive patients who underwent low-dose dynamic CZT SPECT and CAG were enrolled. MBF, MFR and RFR were calculated on the vessel level with dedicated quantitative software, and the difference and correlation of each parameter was compared according to the reference standard of stenosis ≥ 50% or ≥ 75% on CAG, respectively. ROC curves were made by stress MBF (sMBF), rest MBF (rMBF), MFR and RFR. The optimal cut-off values and corresponding diagnostic efficacy were obtained and compared with each other. Results indicated that when stenosis ≥ 50% or ≥ 75% on CAG was used as the reference standard at the vessel level, there was no statistically significant difference in rMBF between the negative group and the positive group (P > 0.05), and the sMBF and MFR in positive groups were significantly lower than that in the negative group (all P < 0.05). There was a moderate to significant correlation between sMBF and MFR, sMBF and RFR, MFR and RFR (all P < 0.0001). These results indicate that low-dose dynamic CZT SPECT imaging can easily obtain the sMBF, MFR and RFR, and there is a good correlation among the three parameters, which has a certain diagnostic value for patients with suspected or known CAD, and is a useful supplement to the conventional qualitative or semi-quantitative diagnostic methods.

Management of non-culprit coronary plaques in patients with acute coronary syndrome

Approximately 50% of patients with ST-segment elevation myocardial infarction (STEMI) have multivessel coronary artery disease, a condition associated with an increased incidence of recurrent ischaemic events and higher mortality. Based on recent evidences, a strategy of staged percutaneous coronary intervention (PCI) of obstructive non-culprit lesions should be considered the gold standard for the management of these patients. However, several issues remain still unresolved. Indeed, what is the optimal timing of staged PCI is not completely defined. Moreover, assessment of intermediate non-culprit lesions represent still a clinical conundrum, as pressure-wire indexes do not seem able to correctly identify those patients in whom deferral is safe. Intracoronary imaging may help to identify untreated non-culprit lesions containing vulnerable plaques that may portend a higher risk of future cardiovascular events. However, there are hitherto no studies demonstrating that preventive PCI of vulnerable plaques or more intensive pharmacological treatment is associated with an improved clinical outcome. In this review, we discuss the recent evolving concepts about management of non-culprit plaques in STEMI patients, proposing a diagnostic and therapeutic algorithm to guide physicians in clinical practice. We also underscore the several knowledge gaps to address in future studies.

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Management of multivessel coronary artery disease in patients with non-ST-elevation myocardial infarction: a complex path to precision medicine

Recent analyses suggest the incidence of acute coronary syndrome is declining in high- and middle-income countries. Despite this, overall rates of non-ST-elevation myocardial infarction (NSTEMI) continue to rise. Furthermore, NSTEMI is a greater contributor to mortality after hospital discharge than ST-elevation myocardial infarction (STEMI). Patients with NSTEMI are often older, comorbid and have a high likelihood of multivessel coronary artery disease (MVD), which is associated with worse clinical outcomes. Currently, optimal treatment strategies for MVD in NSTEMI are less well established than for STEMI or stable coronary artery disease. Specifically, in relation to percutaneous coronary intervention (PCI) there is a paucity of randomized, prospective data comparing multivessel and culprit lesion-only PCI. Given the heterogeneous pathological basis for NSTEMI with MVD, an approach of complete revascularization may not be appropriate or necessary in all patients. Recognizing this, this review summarizes the limited evidence base for the interventional management of non-culprit disease in NSTEMI by comparing culprit-only and multivessel PCI strategies. We then explore how a personalized, precise approach to investigation, therapy and follow up may be achieved based on patient-, disease- and lesion-specific factors.

Why, When and How Should Clinicians Use Physiology in Patients with Acute Coronary Syndromes?

Current data support the use of coronary physiology in patients with acute coronary syndrome (ACS). In patients with ST-elevation MI, the extent of myocardial damage and microvascular dysfunction create a complex conundrum to assimilate when considering clinical management and risk stratification. In this setting, the index of microcirculatory resistance emerged as an accurate tool to identify patients at risk of suboptimal myocardial reperfusion after primary percutaneous coronary intervention who may benefit from novel adjunctive therapies. In the context of non-ST-elevation ACS, coronary physiology should be carefully interpreted and often integrated with intracoronary imaging, especially in cases of ambiguous culprit lesion. Conversely, the functional assessment of bystander coronary disease is favoured by the available evidence, aiming to achieve complete revascularisation. Based on everyday clinical scenarios, the authors illustrate the available evidence and provide recommendations for the functional assessment of infarct-related artery and non-culprit lesions in patients with ACS.

Design and rationale of ischaemia-driven complete revascularisation versus usual care in patients with non-ST-elevation myocardial infarction and multivessel coronary disease: the South Limburg Myocardial Infarction (SLIM) trial

AIMS

To compare ischaemia-driven complete coronary revascularisation by percutaneous coronary intervention (PCI) with usual care in patients with non-ST-elevation myocardial infarction (non-STEMI) and multivessel disease (MVD).

METHODS

The South Limburg Myocardial Infarction (SLIM) trial (NCT03562572) is an investigator-initiated, prospective, multicentre, randomised controlled trial that compares fractional flow reserve (FFR)-guided complete revascularisation during the index procedure with usual care in non-STEMI patients with MVD. A total of 414 patients will be randomised in a 1:1 fashion. The primary endpoint is the composite of all-cause mortality, non-fatal myocardial infarction, and any revascularisation and stroke (MACCE) at 12 months. The secondary endpoints are: MACCE at 24 and 36 months, and the composite of cardiac death, myocardial infarction, any revascularisation, stroke, major bleeding and left ventricular ejection fraction below 45% at 12, 24 and 36 months. Furthermore, quality of life will be assessed by the Patient Health Questionnaire (PHQ-9) and the Short Form (36) Health Survey (SF-36) at 1 and 12 months of follow-up.

CONCLUSION

The SLIM trial aims to provide evidence whether FFR-guided complete revascularisation by PCI is superior to usual care with respect to clinical outcomes (major adverse cardiovascular events) in non-STEMI patients with MVD.

Long-term outcome after deferred revascularization due to negative fractional flow reserve in intermediate coronary lesions

Objectives

The aim was to assess long‐term outcome after deferring intervention of coronary lesions with a fractional flow reserve (FFR) value of >0.80 in a real‐world patient population and then to identify factors associated with deferred target lesion failure (DTLF).

Background

Deferring coronary interventions of intermediate lesions based on FFR measurement is safe, irrespective of the extent of coronary artery disease. However, FFR values near the cut‐off of >0.80 may have less favorable outcome.

Methods

A retrospective analysis was performed in patients with deferred coronary intervention based on FFR value >0.80. The primary endpoint was DTLF, a composite of acute coronary syndrome (ACS) and any coronary revascularization, related to the initially deferred stenosis.

Results

A total of 600 patients, mean age of 66 ± 10 years, and 751 coronary lesions with negative FFR values (mean 0.88 ± 0.04) were included. The mean follow‐up was 27 ± 15 months. DTLF occurred in 44 patients (7.3%), revascularization in 42 (7%), and ACS without revascularization in 2 patients (0.3%). Patients with DTLF more often had diabetes mellitus, previous coronary artery bypass grafting, multivessel disease (MVD), and lower FFR at inclusion. Multivariable regression analysis showed that lower deferred FFR values [FFR 0.81–0.85: hazard ratio (HR) 2.79 (95% CI [confidence interval]; 1.46–5.32), p .002], MVD [HR 1.98 (95% CI; 1.05–3.75), p .036], distal lesions [HR 2.43 (95% CI; 1.29–4.57), p .006], and lesions located in a saphenous vein graft (SVG) [HR 6.35 (95% CI; 1.81–22.28), p .004] were independent predictors for DTLF.

Conclusions

The long‐term rate of DTLF of initially deferred coronary lesions was 7.3%. Independent predictors for DTLF are lower deferred FFR value, the presence of MVD, distal lesions, and lesions in SVG.

Prospective Evaluation of the Strategy of Functionally Optimized Coronary Intervention

Background

Long‐term outcomes after percutaneous coronary intervention (PCI) relate in part to residual ischemia in the treated vessel, as reflected by post‐PCI fractional flow reserve (FFR). The strategy of FFR after PCI and treatment of residual ischemia—known as functionally optimized coronary intervention (FCI)—may be feasible and capable of improving outcomes.

Methods and Results

Feasibility and results of FCI using an optical‐sensor pressure wire were prospectively evaluated in an all‐comer population with 50% to 99% lesions and ischemic FFR (≤0.80; ClinicalTrials.gov identifier NCT03227588). FCI was attempted in 250 vessels in 226 consecutive patients. The PCI success rate was 99.6% (249/250 vessels). FCI technical success—that is, FFR before and after PCI and PCI itself using the FFR wire—was 92% (230/250 vessels). Incidence of residual ischemia in the treated vessel was 36.5%. Approximately a third of these vessels (34.5%, n=29) were considered appropriate for further intervention, with FFR increasing from 0.71±0.07 to 0.81±0.06 (P<0.001). Pressure wire pullback showed FFR ≤0.8 at distal stent edge was 7.9% and 0.7% proximal to the stent. FFR increase across the stent was larger in the ischemic than in the nonischemic group (0.06 [interquartile range: 0.04–0.08] versus 0.03 [interquartile range: 0.01–0.05]; P<0.0001) compatible with stent underexpansion as a contributor to residual ischemia.

Conclusions

FCI is a feasible and safe clinical strategy that identifies residual ischemia in a large proportion of patients undergoing angiographically successful PCI. Further intervention can improve ischemia. The impact of this strategy on long‐term outcomes needs further study.

Outcomes of fractional flow reserve-guided percutaneous coronary interventions in patients with acute coronary syndrome

INTRODUCTION

Fractional flow reserve (FFR) assessment has been validated as an effective tool to guide revascularization of stable coronary artery disease. The role of utilizing FFR in acute coronary syndrome (ACS) is less established.

METHODS

The study population was extracted from the National Readmissions Data (NRD) 2014 using International Classification of Diseases, ninth edition, clinical modification (ICD-9-CM) codes for ACS, percutaneous coronary intervention (PCI), FFR, and periprocedural complications. Study endpoints included all-cause of in-hospital mortality, length of index hospital stay (LOS), acute kidney injury (AKI), bleeding, coronary dissection, total number of stents used, stroke, vascular complications (VCs), and the total charges of index hospitalization.

RESULTS

A total of 304,548 discharges that had the diagnosis of ACS and treated invasively within the same index hospitalization (average age 65.1 years; 64% male) were identified. Among these, 7,832 had FFR guided invasive treatment (2.6%) which was associated with significantly lower in-hospital all-cause mortality (1.1 vs. 3.1%, p < .01), shorter LOS (4.6 vs. 5.3 days, p < .01), less AKI (12.5 vs. 14.6%, p < .01), less bleeding (7.0 vs. 8.5%, p < .01), and lower total charges ($99,805 vs. $105,736). There was no significant difference between both groups in terms of stroke (2.2 vs. 2.3%, p = .41), coronary dissection (0.7 vs. 0.8%, p = .34), VC (1.3 vs. 1.0% p = .01) or the total number of stents used (55.5 vs. 54.5% p = .34).

CONCLUSION

In patients presenting with an ACS FFR- guided PCI, as compared to angiography guided PCI, was associated with lower rates of in-hospital mortality, shorter LOS, less AKI, bleeding and lower hospital charges. There was no significant difference in terms of the incidence of stroke, coronary dissection, VC or the total number of stents used.

The Role of Fractional Flow Reserve and Instantaneous Wave-Free Ratio Measurements in Patients with Acute Coronary Syndrome

PURPOSE OF REVIEW

The role of fractional flow reserve to guide revascularization in patients with stable angina is well established. The instantaneous wave-free ratio (iFR) is an emerging adenosine-free resting index that is non-inferior to FFR and has potential to streamline the functional evaluation of coronary artery disease. The feasibility and utility of intracoronary physiology in patients with acute coronary syndrome (ACS) is unclear. This review will discuss the physiological principles and validity of using FFR and iFR in patients presenting with ACS. We will also provide an overview of the available evidence for their role in guiding revascularization in this patient group.

RECENT FINDINGS

The use of intracoronary physiology in culprit lesions of patients presenting with STEMI is not recommended and its accuracy is uncertain in patients with NSTEMI. In contrast, the physiological assessment of non-culprit vessels with FFR and IFR is a reliable measure of lesion-specific ischemia. Recent studies have demonstrated that FFR-guided revascularization of non-culprit lesions improves clinical outcomes although the role of iFR in this patient cohort is unknown. Physiology-guided revascularization of non-culprit ACS lesions improves clinical outcomes. Future studies investigating the complementary role of plaque morphology, biomechanics, and systemic inflammation may provide clinicians with a more comprehensive framework to guide treatment decisions.

Safety of the Deferral of Coronary Revascularization on the Basis of Instantaneous Wave-Free Ratio and Fractional Flow Reserve Measurements in Stable Coronary Artery Disease and Acute Coronary Syndromes

OBJECTIVES

The aim of this study was to investigate the clinical outcomes of patients deferred from coronary revascularization on the basis of instantaneous wave-free ratio (iFR) or fractional flow reserve (FFR) measurements in stable angina pectoris (SAP) and acute coronary syndromes (ACS).

BACKGROUND

Assessment of coronary stenosis severity with pressure guidewires is recommended to determine the need for myocardial revascularization.

METHODS

The safety of deferral of coronary revascularization in the pooled per-protocol population (n = 4,486) of the DEFINE-FLAIR (Functional Lesion Assessment of Intermediate Stenosis to Guide Revascularisation) and iFR-SWEDEHEART (Instantaneous Wave-Free Ratio Versus Fractional Flow Reserve in Patients With Stable Angina Pectoris or Acute Coronary Syndrome) randomized clinical trials was investigated. Patients were stratified according to revascularization decision making on the basis of iFR or FFR and to clinical presentation (SAP or ACS). The primary endpoint was major adverse cardiac events (MACE), defined as the composite of all-cause death, nonfatal myocardial infarction, or unplanned revascularization at 1 year.

RESULTS

Coronary revascularization was deferred in 2,130 patients. Deferral was performed in 1,117 patients (50%) in the iFR group and 1,013 patients (45%) in the FFR group (p < 0.01). At 1 year, the MACE rate in the deferred population was similar between the iFR and FFR groups (4.12% vs. 4.05%; fully adjusted hazard ratio: 1.13; 95% confidence interval: 0.72 to 1.79; p = 0.60). A clinical presentation with ACS was associated with a higher MACE rate compared with SAP in deferred patients (5.91% vs. 3.64% in ACS and SAP, respectively; fully adjusted hazard ratio: 0.61 in favor of SAP; 95% confidence interval: 0.38 to 0.99; p = 0.04).

CONCLUSIONS

Overall, deferral of revascularization is equally safe with both iFR and FFR, with a low MACE rate of about 4%. Lesions were more frequently deferred when iFR was used to assess physiological significance. In deferred patients presenting with ACS, the event rate was significantly increased compared with SAP at 1 year.

Functional disorders in non-culprit coronary arteries and their implications in patients with acute myocardial infarction

Approximately 30-50% of patients with ST-segment elevation acute myocardial infarction have multivessel disease. The physiology of the non-culprit artery (NCA) is complex and represents a challenge to physicians as, while these plaques are presumably stable, clinical data show that they frequently lead to major adverse cardiovascular events. In addition the presence of microvascular and endothelial dysfunction may have prognostic implications and interfere with current physiological indices for stenosis severity assessment. In this review we aim to summarize current methods to study the microcirculation, discuss the evidence available regarding the endothelium and the microvascular compartment of the NCA; the best strategies to perform a complete revascularization based on proven ischemia; real limitations associated to hyperemic stenosis indices; and the potential role of novel resting-indices in this specific acute context.

Fractional flow reserve and frequency of PCI in patients with coronary artery disease

BACKGROUND

Fractional flow reserve (FFR) guided percutaneous coronary intervention (PCI) has been validated in patients with stable coronary artery disease (CAD) but has not yet been verified under specific conditions such as heart failure or microvascular dysfunction. The aim of the present study was to examine the influence of specific patient comorbidities on FFR values and thus the frequency of PCI in patients with intermediate coronary stenosis.

METHODS

A total of 652 patients with CAD and intermediate coronary stenosis who were assessed for FFR were included in this retrospective study. In a subgroup analysis, specific comorbidities such as heart failure with non-ST-segment-elevated acute coronary syndrome (NSTE-ACS), heart failure, diabetes mellitus, atrial fibrillation (AF), and left ventricular hypertrophy (LVH) were considered.

RESULTS

In all lesions with an FFR ≤ 0.80 (n = 227/808, 28.1%), PCI was performed using drug-eluting stents. Pathological FFR values (FFR ≤ 0.80) before PCI were most frequently observed in the left anterior descending artery (LAD; n = 168/418, 39.9%) followed by the right coronary artery (RCA; n = 37/178, 20.7%) and the left circumflex artery (LCX; 22/223, 9.8%). The comorbidities NSTE-ACS (p = 0.28), heart failure with reduced ejection fraction (HFrEF; p = 0.63), heart failure with preserved ejection fraction (HFpEF; p = 0.3719), diabetes mellitus (p = 0.177), or LVH (p = 0.407) had no major impact on the occurrence of pathological FFR values; there was also no association between FFR and the occurrence of lesions in the different target vessels.

CONCLUSION

The occurrence of pathological FFR values, most frequently documented in the LAD, was the same in patients with or without HFrEF, HFpEF, diabetes mellitus, AF, and LVH, demonstrating that these comorbidities did not influence FFR values and, thus, the indication for PCI.

Rational and design of the INtentional COronary revascularization versus conservative therapy in patients undergOing successful peripheRAl arTEry revascularization due to critical limb ischemia trial (INCORPORATE trial)

Critical limb ischemia is associated with excessively high risk for cardiovascular events, including myocardial infarction and death. Additionally, in this patient population non-invasive evaluation of coronary artery disease is limited due to (1) inability of exercise testing, (2) frequent occurrence of balanced ischemia and (3) frequent occurrence of diffuse coronary calcification. Intentional Coronary Revascularization Versus Conservative Therapy in Patients Undergoing Peripheral Artery Revascularization Due to Critical Limb Ischemia trial (INCORPORATE trial) is a multicentric international randomized open label clinical trial. Trial will recruit patients, who underwent successful peripheral artery revascularization due to critical limb ischemia and randomize 1:1 to conservative medical therapy versus an immediate invasive strategy to investigate and treat coronary artery disease. The objective is to evaluate whether intentional invasive strategy with ischemia targeted reasonably complete coronary revascularization is superior as compared to conventional primarily conservative approach in terms of spontaneous myocardial infarction and overall survival at 12 months follow-up. The trial is registered at clinicaltrials.gov (NCT03712644).

Long-term outcomes after fractional flow reserve-guided percutaneous coronary intervention in patients with severe coronary stenosis

Objective

To explore the safety and efficacy of FFR-guided percutaneous coronary intervention (PCI) in vessels with severe diameter stenosis.

Methods & Results

Of 1090 patients undergoing fractional flow reserve (FFR) assessment from 2002 to 2009, we identified 167 patients in whom FFR was measured in at least one 70%–89% stenotic lesion. These patients were subdivided into an FFR-defer group (n = 49) if PCI was deferred (FFR > 0.80), and an FFR-perform group (n = 118) if PCI was performed (FFR ≤ 0.80). Comparatively, an additional 1176 patients undergoing PCI in at least one lesion with 70%–89% stenosis but without measurement of FFR served as a control (angiography-guided) group. Clinical outcomes were compared during a median follow-up of 49.0 months. The 5-year Kaplan-Meier estimated revascularization rates were 16% in the FFR-defer group and 33% in the FFR-perform group (P = 0.046). The incidence of major adverse cardiac events were comparable in these two groups (HR = 0.82, 95% CI: 0.37–1.82, P = 0.63). The number of stents placed was significantly lower in the FFR-guided group (0.9 ± 0.8 vs. 1.4 ± 0.8, P < 0.001).

Conclusions

Functional revascularization for lesions with visually severe stenosis is clinically safe and associated with fewer stents use. This study suggests that extending the use of FFR to more severe coronary lesions may be reasonable.

Revascularization Strategies for Non-ST-Elevation Myocardial Infarction

PURPOSE OF REVIEW

Non-ST-elevation myocardial infarction (NSTEMI) is an urgent medical condition that requires prompt application of simultaneous pharmacologic and non-pharmacologic therapies. The variation in patient clinical characteristics coupled with the multitude of treatment modalities makes optimal and timely management challenging. This review summarizes risk stratification of patients, the role and timing of revascularization, and highlights important considerations in the revascularization approach with attention to individual patient characteristics.

RECENT FINDINGS

The early invasive management of NSTEMI has fostered a reduction in future ischemic events. Risk calculators are helpful in determining which patients should receive early invasive management. As many patients have multivessel disease, identifying the true culprit lesion can be challenging. Special attention should be given to those at the highest risk, such as diabetics, patients with renal failure, and those with left main disease. In patients with acute coronary syndrome, the decision and mode of revascularization should carefully integrate the patient's clinical characteristics as well as the complexity of the coronary anatomy.

Fractional flow reserve in acute coronary syndrome: a meta-analysis and systematic review

Background

The utility of fractional flow reserve (FFR) to guide revascularisation in the management of acute coronary syndrome (ACS) remains unclear.

Objective

This study aims to compare the clinical outcomes of patients following FFR-guided revascularisation for either ACS or stable angina (SA) and in particular focuses on the outcome of those with deferred revascularisation after FFR.

Methods

A meta-analysis of existing literature was performed. Outcomes including the rate of major adverse cardiovascular events (MACE), recurrent myocardial infarction (MI), mortality and unplanned revascularisation were analysed.

Results

A review of 937 records yielded 9 studies comparing 5457 patients, which were included in the analyses. Patients with ACS had a higher rate of recurrent MI (OR 1.81, p=0.02) and a strong trend towards more MACE and all-cause mortality compared with patients with SA when treated by an FFR-guided revascularisation strategy. Deferral of invasive therapy on the basis of FFR led to a higher rate of MACE (17.6% vs 7.3 %; p=0.004), recurrent MI (5.3% vs 1.5%, p=0.001) and target vessel revascularisation (16.4% vs 5.6 %; p=0.02) in patients with ACS, and a strong trend towards a higher cardiovascular mortality at follow-up when compared with patients with SA.

Conclusion

The event rate in patients with ACS is much higher than SA despite following an FFR-guided revascularisation strategy. Deferring revascularisation does not appear to be as safe for ACS as it is for SA using contemporary FFR cut-offs validated in SA. Refinement of the therapeutic strategy for patients with ACS with multivessel disease is needed to redress the balance.

Clinical use of physiological lesion assessment using pressure guidewires: an expert consensus document of the Japanese Association of Cardiovascular Intervention and Therapeutics

In this document, the background, concept, and current evidence are briefly summarized. The focus is on the clinical application of physiological lesion assessment from a practical standpoint for facilities that do not have ample experience. Finally, the characteristics of new resting indexes are summarized.