FFR-Guided PCI Optimization Directed by High-Definition IVUS Versus Standard of Care: The FFR REACT Trial

Randomized Study Comparing Angiography Guidance With Physiology Guidance After PCI: The EASY-PREDICT Study

BACKGROUND

Physiology assessment of coronary lesion prepercutaneous coronary intervention (PCI) using hyperemic and nonhyperemic pressure ratios is useful to determine if a lesion requires treatment. Whether the physiology after PCI is superior to angiography guidance only is unknown. The study sought to investigate whether post-PCI physiology improves clinical outcomes compared with standard angiographic guidance.

METHODS

All-comers patients referred for diagnostic angiography and possible PCI were recruited in a high-volume tertiary care hospital. After uncomplicated PCI, patients were randomized to angiography guidance or target vessel physiology, including nonhyperemic pressure ratio (resting distal coronary pressure to aortic pressure ratio and diastolic pressure ratio) and fractional flow reserve. The primary outcome was the rate of target vessel failure, including cardiac death, myocardial infarction, and target vessel revascularization at 18 months post-PCI. Angina score, medications, and quality of life were also assessed.

RESULTS

Two hundred twenty-one patients were randomized in the angiography group (110 patients, 166 lesions) and the physiology group (111 patients, 159 lesions). Immediate post-PCI physiology results were deemed suboptimal in 22 (17%) cases, and operators performed further optimization steps. Final post-PCI results were resting distal coronary pressure to aortic pressure ratio of 0.95±0.04, the diastolic pressure ratio of 0.94±0.06, and the fractional flow reserve of 0.90±0.07. Ultimately, 9 lesions (7%) remained with fractional flow reserve values ≤0.80. At 18-month follow-up, target vessel failure was 17.4% in the angiography group and 18% in the physiology group (P=0.88). Rates of cardiac death (1% versus 0%; P=0.32), myocardial infarction (13% versus 11%; P=0.66), and target vessel revascularization (4% versus 7%; P=0.24) remained similar in both groups. No difference in angina score, medication, or quality of life was found.

CONCLUSIONS

In all-comers patients undergoing uncomplicated PCI, routine post-PCI physiology assessment was not associated with clinical benefit compared with standard angiographic guidance. Further study is required to determine how post-PCI physiology guidance can be helpful in selected lesions.

REGISTRATION

URL: XXX; Unique identifier: NCT04929496.

The Pullback Pressure Gradient: A Physiologic Index to Differentiate Focal From Diffuse Coronary Artery Disease

Fractional flow reserve is the most widely used physiologic index to establish the functional significance of epicardial coronary artery disease (CAD). Fractional flow reserve guides clinical decisions toward or against coronary revascularization based on a single binary decision threshold indicative of myocardial ischemia. CAD pathophysiological patterns can be evaluated by assessing the distribution of pressure losses along the coronary vessel, often displayed as a "pullback curve." Until recently, the information provided by the pullback curves was visually and subjectively interpreted, which is associated with interobserver variability. The pullback pressure gradient is a novel index that addresses this gap by assessing the longitudinal distribution of the CAD, quantifying it on a scale from 0 to 1, with higher values indicative of predominantly focal CAD and lower values of predominantly diffuse CAD. This review provides a comprehensive analysis and critical appraisal of pullback pressure gradient and future directions.

Post-PCI coronary physiology: clinical outcomes and can we optimize?

Invasive coronary physiology is well-established for identifying stable lesions appropriate for revascularization with percutaneous coronary intervention (PCI). Furthermore, fractional flow reserve (FFR)-guided PCI is associated with better clinical outcomes compared with routine angiography-guided PCI. The rise of intravascular imaging-guided PCI has generated great interest in optimizing the technical results of a PCI procedure, and this has now extended to an interest in optimizing coronary physiology following PCI. In this review, we examine the relationship between post-PCI physiology and clinical outcomes, including relief from angina, a relationship which is independent of the initial FFR value. In addition, we highlight the utility of pullback coronary pressure assessment for identifying mechanisms of suboptimal final FFR, such as patient characteristics (diffuse atherosclerosis), PCI technique, and certain artifacts in pressure-wire measurements. It is our view that the final FFR value can only be modestly improved, or optimized, with respect to clinical outcomes. The most significant clinical impact is obtained from the change in FFR (ΔFFR) from before to after PCI, which can be anticipated ahead of time by operators and used to guide lesion selection, or exclusion, for PCI.

Correlation Between Intravascular Ultrasound Minimum Luminal Area and Quantitative Minimum Luminal Area in Intermediate Coronary Lesions

BACKGROUND

Chronic coronary syndrome (CCS) is a common disease worldwide. Advances in technology, including quantitative coronary angiography, have improved CCS management. In the present study, we aim to investigate the correlation and agreement between intravascular ultrasound minimum luminal area (IVUSMLA) and quantitative minimum luminal area (QMLA) in CCS patients with intermediate coronary lesions.

METHODS

Data from CCS patients with at least one-vessel coronary occlusion from March 2022 to March 2023 were collected. Gathered data included patients' age, gender, QMLA, IVUSMLA, and patients' previous medical history, including hypertension, diabetes, and smoking. The target lesion in this study was intermediate (50% to 70%) stenosis. Agreement between IVUSMLA and QMLA was assessed using the Bland-Altman plot. A p-value (p) of less than 0.05 was considered statistically significant. R version 4.4.1 software (R Foundation for Statistical Computing, Vienna, Austria) was used for data analysis.

RESULTS

This study included 52 (59.1%) men and 36 (40.9%) women with a mean age of 67.15 ± 10.63 and 64 ± 12.61 (p = 0.533), respectively. The mean for IVUSMLA and QMLA was 2.80 ± 1.54 and 2.6 ± 1.57, respectively. QMLA was highly correlated with IVUSMLA (r = 0.997; p <0.001). Both QMLA and IVUSMLA had moderately good agreement, presenting with small mean difference values but large values of root mean squared deviation (IVUSMLA - QMLA = 0.13 ± 0.11).

CONCLUSION

IVUSMLA and QMLA are highly correlated to each other and have good agreement. So, QMLA can be used instead of IVUSMLA in intermediate coronary lesions.

Results of systematic patient outcome monitoring: Does post-dilatation during angiography-guided percutaneous coronary intervention improve clinical outcomes?

OBJECTIVES

This study evaluates clinical outcomes after implementing a liberal post-dilatation strategy during PCI.

BACKGROUND

Post-dilatation after percutaneous coronary intervention (PCI) is performed to achieve optimal stent expansion and reduce complications. However, its prognostic effects are unclear and conflicting.

METHODS

This study is a pre-post-intervention analysis of two cohorts, before (2015-2017) and after (2018-2020) implementation of a liberal post-dilatation strategy. The primary end point consisted of major adverse cardiovascular events (MACE) at 30 days. Secondary end points consisted of the individual components of the primary end point as well as 1 year mortality and target vessel revascularization.

RESULTS

A total of 10,153 patients were included: 5,383 in the pre-cohort and 4,770 in the post-cohort. The 30-day MACE was 5.00% in the pre-cohort and 4.09% in the post-cohort (p = 0.008; OR 0.75 (CI 0.61-0.93)). There was a significant difference between the pre- and post-cohort in 30-day mortality, respectively, 2.91% and 2.25% (p = .01; OR 0.70 (CI 0.53-0.93)), and MI at 30 days, 1.17% versus 0.59% (p = .003; OR 0.49 (CI 0.31-0.78)). At 1 year, there was a significant difference in mortality between the pre-cohort, 5.84%, and post-cohort, 5.19% (p = .02; OR 0.79 (CI 0.66-0.96)).

CONCLUSIONS

A liberal post-dilatation strategy after PCI was associated with a significant decrease in 30-day MACE, 30-day MI, 30-day mortality, and 1-year mortality. Future studies are warranted to validate the causality between post-dilatation and improvement of clinical outcomes.

Ultra-Low-Contrast PCI: A Structured Approach to Reducing Dependence on Contrast Vessel Opacification in PCI

Since its inception, percutaneous coronary intervention (PCI) has relied upon vessel opacification with iodinated contrast to plan, guide, and assess the results of the procedure. Yet revisiting this fundamental concept is important in contemporary PCI practice, especially in patients with high-risk clinical or anatomical profiles. In addition to decreasing the probability of acute kidney injury during PCI, limiting the volume of iodinated contrast allows the operator to perform more thorough interventions by relying on intracoronary imaging and physiology, ultimately contributing to more complete revascularization and improving the efficacy and durability of the intervention. Ultra-low-contrast PCI (ULCPCI) may thus be useful in performing PCI not only in patients with chronic renal dysfunction but also in those with multivessel coronary artery disease, impaired left ventricular function, and many other scenarios. The aim of this review is to highlight contemporary PCI scenarios in which a ULCPCI approach may be beneficial. The authors provide a structured approach to address the challenges faced by operators in transitioning from conventional contrast-based interventions to ULCPCI, with practical solutions that are accessible to most interventionalists. The reader will learn that ULCPCI is feasible in contemporary practice as a result of technological innovation, the implementation of dedicated skills, and redefining the role of angiography as the cornerstone of contemporary PCI.

Prognostic Value of Postpercutaneous Coronary Intervention Murray-Law-Based Quantitative Flow Ratio: Post Hoc Analysis From FLAVOUR Trial

Background

Coronary physiology measured by fractional flow reserve (FFR) is superior to angiography for assessing the efficacy of percutaneous coronary intervention (PCI). Yet, the clinical adoption of post-PCI FFR is limited. Murray law-based quantitative flow ratio (μQFR) may represent a promising alternative, as it can quickly compute FFR from a single angiographic view.

Objectives

The authors aimed to investigate the potential role of post-PCI μQFR in predicting clinical outcomes.

Methods

This was a post hoc blinded analysis of the FLAVOUR trial. Patients with angiographically intermediate lesions randomized 1:1 to receive FFR or intravascular ultrasound-guided PCI were included. Post-PCI μQFR was assessed in successfully stented vessels, blinded to clinical outcomes. Suboptimal physiological outcome post-PCI was defined a priori as post-PCI μQFR <0.90. The primary endpoint was 2-year target vessel failure, including cardiac death, target vessel myocardial infarction, and target vessel revascularization. Secondary endpoints included the diagnostic concordance of pre-PCI μQFR with FFR in the FFR-guidance arm.

Results

Post-PCI μQFR was successfully analyzed in 806 vessels from 777 participants (feasibility 97.0% [806 of 831]). Suboptimal physiological outcome post-PCI was identified in 24.7% (199 of 806) of vessels and post-PCI μQFR <0.90 was associated with higher risk of 2-year target vessel failure (6.1% [12 of 199] vs 2.7% [16 of 607]; HR: 2.45 [95% CI: 1.14-5.26]; P = 0.022). Pre-PCI μQFR was obtained in 877 of 919 vessels (feasibility 95.4%), showing 90% accuracy, 82% sensitivity, and 94% specificity for identifying physiologically significant stenosis defined by pre-PCI FFR ≤0.80.

Conclusions

In patients with intermediate lesions who underwent PCI with contemporary imaging or physiology guidance, lower post-PCI μQFR values predict subsequent adverse events. (Fractional FLow Reserve And IVUS for Clinical OUtcomes in Patients With InteRmediate Stenosis [FLAVOUR]; NCT02673424).

Fractional Flow Reserve Directed Percutaneous Coronary Intervention Optimization Using High-Definition Intravascular Ultrasound in Non-ST-Segment Elevation Acute Coronary Syndrome Versus Chronic Coronary Syndrome

BACKGROUND

Intravascular ultrasound (IVUS)-guided optimization of suboptimal fractional flow reserve (FFR) following percutaneous coronary intervention (PCI) results in a significant increase in both post-PCI FFR and minimal lumen and stent areas (MLA and MSA, respectively). However, the impact of clinical presentation with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) versus chronic coronary syndrome (CCS) on the efficacy of PCI optimization remains unknown.

METHODS

This was a prespecified subgroup analysis of the FFR REACT trial comparing IVUS-guided PCI optimization versus no further treatment in 291 patients with a post-PCI FFR < 0.90. Post-PCI physiology and pre optimization IVUS findings were compared between patients presenting with NSTE-ACS versus CCS, as well as optimization strategy, final FFR and IVUS findings.

RESULTS

Out of 291 patients, 130 (44.7%) presented with NSTE-ACS. Median post-PCI FFR was similar in patients with NSTE-ACS and CCS (0.85 for both, p = 0.55). Pre optimization IVUS findings did not differ significantly between both groups and subsequent optimization strategy was comparable (p = 0.71). In both NSTE-ACS and CCS, optimization resulted in a significant increase (p < 0.01 for all) of similar magnitude in median FFR (0.02 vs. 0.03, p = 0.80), MLA (0.37 vs. 0.50 mm2, p = 0.46) and MSA (0.29 vs. 0.32 mm2, p = 0.61), respectively. The clinical impact of IVUS-guided optimization on 2-year target vessel failure showed no signs of heterogeneity based on clinical presentation (interaction p = 0.36).

CONCLUSIONS

In patients undergoing FFR-directed IVUS-guided optimization, post-PCI FFR, pre optimization IVUS findings and optimization strategy did not differ significantly between patients presenting with either NSTE-ACS or CCS, with comparable improvements in FFR, MLA and MSA.

The Impact of Microvascular Resistance Reserve on the Outcome of Patients With STEMI

BACKGROUND

Microvascular resistance reserve (MRR) can characterize coronary microvascular dysfunction (CMD); however, its prognostic impact in ST-segment elevation myocardial infarction (STEMI) patients remains undefined.

OBJECTIVES

This study sought to investigate the prevalence of CMD in STEMI patients and to elucidate the prognostic performance of MRR.

METHODS

This prospective cohort study enrolled 210 STEMI patients with multivessel disease who underwent successful revascularization and returned at 3 months for coronary physiology assessments with bolus thermodilution. The prevalence of CMD (MRR <3) and the association between MRR and major adverse cardiovascular and cerebrovascular events (MACCEs) at 12 months were investigated.

RESULTS

The median age of patients was 65 years, and 59.5% were men. At the 3-month follow-up, 56 patients (27%) had CMD (MRR <3.0). The number of MACCEs at 12 months was higher in patients with vs without CMD (48.2% vs 11.0%; P < 0.001). MRR was independently associated with 12-month MACCEs (HR: 0.45 per unit increase; 95% CI: 0.31-0.67; P < 0.001) and with stroke, heart failure, and poorer recovery in left ventricular systolic function. The areas under the receiver-operating characteristic curves for predicting MACCEs at 12 months with fractional flow reserve, coronary flow reserve (CFR), the index of microvascular resistance (IMR), and MRR were 0.609, 0.762, 0.781, and 0.743, respectively. The prognostic performance of CFR, IMR, and MRR were all comparable.

CONCLUSIONS

The novel parameter MRR is a prognostic marker of MACCEs in STEMI patients with a comparable performance to CFR and IMR. (Impact of TMAO Serum Levels on Hyperemic IMR in STEMI Patients [TAMIR]; NCT05406297).

Comparison between Imaging and Physiology in Guiding Coronary Revascularization: A Meta-Analysis

Background: Percutaneous coronary intervention (PCI) is a widely used revascularization strategy for coronary artery disease. The choice between imaging-guided and physiology-guided PCI has been a subject of debate. This meta-analysis aims to systematically compare outcomes between imaging and physiology-guided PCI and management of intermediate coronary lesions (ICLs). Methods: A comprehensive literature search was conducted across major databases for studies published up to December 2023 following PRISMA guidelines. Seven eligible studies comparing imaging-guided and physiology-guided PCI were selected for the final analysis. Relevant outcome measures included major adverse cardiovascular events (MACE), target vessel revascularization (TVR), target vessel failure (TVF), and target lesion revascularization (TLR). Subgroup analysis was performed for ICLs. Results: A total of 5701 patients were included in the meta-analysis. After a mean follow-up of 2.1 years, imaging-guided PCI was associated with lower rates of TVR compared to physiology-guided PCI (OR 0.70, 95% CI 0.52-0.95, p = 0.02); concerning MACE, TVF, and TLR, no differences were found. When the analysis was restricted to studies considering ICLs management, there were no differences between the two techniques. Meta regression analysis did not show any impact of acute coronary syndromes (ACS) presentation on MACE and TVR. Conclusions: The findings suggest that imaging-guided PCI may reduce the need for future revascularization of the target vessel compared to the functional-guided approach, and this result was not influenced by ACS presentation. These results may have important implications for clinical practice, guiding interventional cardiologists in selecting the most appropriate guidance strategy.

Cost-Effectiveness of Intravascular Imaging-Guided Complex PCI: Prespecified Analysis of RENOVATE-COMPLEX-PCI Trial

BACKGROUND

Although clinical benefits of intravascular imaging-guided percutaneous coronary intervention (PCI) in patients with complex coronary artery lesions have been observed in previous trials, the cost-effectiveness of this strategy is uncertain.

METHODS

RENOVATE-COMPLEX-PCI (Randomized Controlled Trial of Intravascular Imaging Guidance vs Angiography-Guidance on Clinical Outcomes After Complex Percutaneous Coronary Intervention) was conducted in Korea between May 2018 and May 2021. This prespecified cost-effectiveness substudy was conducted using Markov model that simulated 3 states: (1) post-PCI, (2) spontaneous myocardial infarction, and (3) death. A simulated cohort was derived from the intention-to-treat population, and input parameters were extracted from either the trial data or previous publications. Cost-effectiveness was evaluated using time horizon of 3 years (within trial) and lifetime. The primary outcome was incremental cost-effectiveness ratio (ICER), an indicator of incremental cost on additional quality-adjusted life years (QALYs) gained, in intravascular imaging-guided PCI compared with angiography-guided PCI. The current analysis was performed using the Korean health care sector perspective with reporting the results in US dollar (1200 Korean Won, ₩=1 dollar, $). Willingness to pay threshold was $35 000 per QALY gained.

RESULTS

A total of 1639 patients were included in the trial. During 3-year follow-up, medical costs ($8661 versus $7236; incremental cost, $1426) and QALY (2.34 versus 2.31; incremental QALY, 0.025) were both higher in intravascular imaging-guided PCI than angiography-guided PCI, resulting incremental cost-effectiveness ratio of $57 040 per QALY gained within trial data. Conversely, lifetime simulation showed total cumulative medical cost was reversed between the 2 groups ($40 455 versus $49 519; incremental cost, -$9063) with consistently higher QALY (8.24 versus 7.89; incremental QALY, 0.910) in intravascular imaging-guided PCI than angiography-guided PCI, resulting in a dominant incremental cost-effectiveness ratio. Consistently, 70% of probabilistic iterations showed cost-effectiveness of intravascular imaging-guided PCI in probabilistic sensitivity analysis.

CONCLUSIONS

The current cost-effectiveness analysis suggests that imaging-guided PCI is more cost-effective than angiography-guided PCI by reducing medical cost and increasing quality-of-life in complex coronary artery lesions in long-term follow-up.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03381872.

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.

Physiology- or Imaging-Guided Strategies for Intermediate Coronary Stenosis

Importance

Treatment strategies for intermediate coronary lesions guided by fractional flow reserve (FFR) and intravascular ultrasonography (IVUS) have shown comparable outcomes. Identifying low-risk deferred vessels to ensure the safe deferral of percutaneous coronary intervention (PCI) and high-risk revascularized vessels that necessitate thorough follow-up can help determine optimal treatment strategies.

Objectives

To investigate outcomes according to treatment types and FFR and IVUS parameters after FFR- or IVUS-guided treatment.

Design, Setting, and Participants

This cohort study included patients with intermediate coronary stenosis from the Fractional Flow Reserve and Intravascular Ultrasound-Guided Intervention Strategy for Clinical Outcomes in Patients With Intermediate Stenosis (FLAVOUR) trial, an investigator-initiated, prospective, open-label, multicenter randomized clinical trial that assigned patients into an IVUS-guided strategy (which recommended PCI for minimum lumen area [MLA] ≤3 mm2 or 3 mm2 to 4 mm2 with plaque burden [PB] ≥70%) or an FFR-guided strategy (which recommended PCI for FFR ≤0.80). Data were analyzed from November to December 2022.

Exposures

FFR or IVUS parameters within the deferred and revascularized vessels.

Main Outcomes and Measures

The primary outcome was target vessel failure (TVF), a composite of cardiac death, target vessel myocardial infarction, and revascularization at 2 years.

Results

A total of 1619 patients (mean [SD] age, 65.1 [9.6] years; 1137 [70.2%] male) with 1753 vessels were included in analysis. In 950 vessels for which revascularization was deferred, incidence of TVF was comparable between IVUS and FFR groups (3.8% vs 4.1%; P = .72). Vessels with FFR greater than 0.92 in the FFR group and MLA greater than 4.5 mm2 or PB of 58% or less in the IVUS group were identified as low-risk deferred vessels, with a decreased risk of TVF (hazard ratio [HR], 0.25 [95% CI, 0.09-0.71]; P = .009). In 803 revascularized vessels, the incidence of TVF was comparable between IVUS and FFR groups (3.6% vs 3.7%; P = .95), which was similar in the revascularized vessels undergoing PCI optimization (4.2% vs 2.5%; P = .31). Vessels with post-PCI FFR of 0.80 or less in the FFR group or minimum stent area of 6.0 mm2 or less or with PB at stent edge greater than 58% in the IVUS group had an increased risk for TVF (HR, 7.20 [95% CI, 3.20-16.21]; P < .001).

Conclusions and Relevance

In this cohort study of patients with intermediate coronary stenosis, FFR- and IVUS-guided strategies showed comparable outcomes in both deferred and revascularized vessels. Binary FFR and IVUS parameters could further define low-risk deferred vessels and high-risk revascularized vessels.

Changes in post-PCI physiology based on anatomical vessel location: a DEFINE PCI substudy

BACKGROUND

Anatomical vessel location affects post-percutaneous coronary intervention (PCI) physiology.

AIMS

We aimed to compare the post-PCI instantaneous wave-free ratio (iFR) in left anterior descending (LAD) versus non-LAD vessels and to identify the factors associated with a suboptimal post-PCI iFR.

METHODS

DEFINE PCI was a multicentre, prospective, observational study in which a blinded post-PCI iFR pullback was used to assess residual ischaemia following angiographically successful PCI.

RESULTS

Pre- and post-PCI iFR recordings of 311 LAD and 195 non-LAD vessels were compared. Though pre-PCI iFR in the LAD vessels (median 0.82 [0.63, 0.86]) were higher compared with those in non-LAD vessels (median 0.72 [0.49, 0.84]; p<0.0001), post-PCI iFR were lower in the LAD vessels (median 0.92 [0.88, 0.94] vs 0.98 [0.95, 1.00]; p<0.0001). The prevalence of a suboptimal post-PCI iFR of <0.95 was higher in the LAD vessels (77.8% vs 22.6%; p<0.0001). While the overall frequency of residual physiological diffuse disease (31.4% vs 38.6%; p=0.26) and residual focal disease in the non-stented segment (49.6% vs 50.0%; p=0.99) were similar in both groups, residual focal disease within the stented segment was more common in LAD versus non-LAD vessels (53.7% vs 27.3%; p=0.0009). Improvement in iFR from pre- to post-PCI was associated with angina relief regardless of vessel location.

CONCLUSIONS

After angiographically successful PCI, post-PCI iFR is lower in the LAD compared with non-LAD vessels, resulting in a higher prevalence of suboptimal post-PCI iFR in LAD vessels. This difference is, in part, due to a greater frequency of a residual focal pressure gradient within the stented segment which may be amenable to more aggressive PCI.

Preprocedural physiological assessment of coronary disease patterns to predict haemodynamic outcomes post-PCI

BACKGROUND

Even with intracoronary imaging-guided stent optimisation, suboptimal haemodynamic outcomes post-percutaneous coronary intervention (PCI) can be related to residual lesions in non-stented segments. Preprocedural assessment of pathophysiological coronary artery disease (CAD) patterns could help predict the physiological response to PCI.

AIMS

The aim of this study was to assess the relationship between preprocedural pathophysiological haemodynamic patterns and intracoronary imaging findings, as well as their association with physiological outcomes immediately post-PCI.

METHODS

Data from 206 patients with chronic coronary syndrome enrolled in the ASET-JAPAN study were analysed. Pathophysiological CAD patterns were characterised using Murray law-based quantitative flow ratio (μQFR)-derived indices acquired from pre-PCI angiograms. The diffuseness of CAD was defined by the pullback pressure gradient (PPG) index. Intracoronary imaging in stented segments after stent optimisation was also analysed.

RESULTS

In the multivariable analysis, diffuse disease - defined by the pre-PCI μQFR-PPG index - was an independent factor for predicting a post-PCI μQFR <0.91 (per 0.1 decrease of PPG index, odds ratio 1.57, 95% confidence interval: 1.07-2.34; p=0.022), whereas the stent expansion index (EI) was not associated with a suboptimal post-PCI μQFR. Among vessels with an EI ≥80% and post-PCI μQFR <0.91, 84.0% of those vessels had a diffuse pattern preprocedure. There was no significant difference in EI between vessels with diffuse disease and those with focal disease. The average plaque burden in the stented segment was significantly larger in vessels with a preprocedural diffuse CAD pattern.

CONCLUSIONS

A physiological diffuse pattern preprocedure was an independent factor in predicting unfavourable immediate haemodynamic outcomes post-PCI, even after stent optimisation using intracoronary imaging. Preprocedural assessment of CAD patterns could identify patients who are likely to exhibit superior immediate haemodynamic outcomes following PCI.

Impact of Post-PCI FFR Stratified by Coronary Artery

BACKGROUND

Low fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) has been associated with adverse clinical outcomes. Hitherto, this assessment has been independent of the epicardial vessel interrogated.

OBJECTIVES

This study sought to assess the predictive capacity of post-PCI FFR for target vessel failure (TVF) stratified by coronary artery.

METHODS

We performed a systematic review and individual patient-level data meta-analysis of randomized clinical trials and observational studies with protocol-recommended post-PCI FFR assessment. The difference in post-PCI FFR between left anterior descending (LAD) and non-LAD arteries was assessed using a random-effect models meta-analysis of mean differences. TVF was defined as a composite of cardiac death, target vessel myocardial infarction, and clinically driven target vessel revascularization.

RESULTS

Overall, 3,336 vessels (n = 2,760 patients) with post-PCI FFR measurements were included in 9 studies. The weighted mean post-PCI FFR was 0.89 (95% CI: 0.87-0.90) and differed significantly between coronary vessels (LAD = 0.86; 95% CI: 0.85 to 0.88 vs non-LAD = 0.93; 95% CI: 0.91-0.94; P < 0.001). Post-PCI FFR was an independent predictor of TVF, with its risk increasing by 52% for every reduction of 0.10 FFR units, and this was mainly driven by TVR. The predictive capacity for TVF was poor for LAD arteries (AUC: 0.52; 95% CI: 0.47-0.58) and moderate for non-LAD arteries (AUC: 0.66; 95% CI: 0.59-0.73; LAD vs non-LAD arteries, P = 0.005).

CONCLUSIONS

The LAD is associated with a lower post-PCI FFR than non-LAD arteries, emphasizing the importance of interpreting post-PCI FFR on a vessel-specific basis. Although a higher post-PCI FFR was associated with improved prognosis, its predictive capacity for events differs between the LAD and non-LAD arteries, being poor in the LAD and moderate in the non-LAD vessels.

Intravascular Ultrasound vs. Fractional Flow Reserve for Percutaneous Coronary Intervention Optimization in Long Coronary Artery Lesions

BACKGROUND

intravascular ultrasound (IVUS) and fractional flow reserve (FFR) have both been shown to be superior to angiography in optimizing percutaneous coronary intervention (PCI). However, there is still a lack of comparative studies between PCI optimization using physiology and intravascular imaging head-to-head. The aim of this study was to compare the effectiveness of FFR and IVUS PCI optimization strategies on the functional PCI result (assessed with FFR) immediately post-PCI and at 9-12 months after the treatment of long coronary lesions.

METHODS

This was a single-center study comparing post-PCI FFR between two different PCI optimization strategies (FFR and IVUS). The study included 154 patients who had hemodynamically significant long lesions, necessitating a stent length of 30 mm or more. The procedural outcomes were functional PCI result immediately post-PCI and at 9-12 months after treatment. Clinical outcomes included target vessel failure (TVF) and functional target vessel restenosis rate during follow-up.

RESULTS

Baseline clinical characteristics and FFR (0.65 [0.55-0.71]) did not differ significantly between the two groups and the left anterior descending artery was treated in 82% of cases. The FFR optimization strategy resulted in a significantly shorter stented segment (49 mm vs. 63 mm, p = 0.001) compared to the IVUS optimization strategy. Although the rates of optimal functional PCI result (FFR > 0.9) did not significantly differ between the FFR and IVUS optimization strategies, a proportion of patients in the FFR group (12%) experienced poor post-PCI functional outcome with FFR values ≤ 0.8, which was not observed in the IVUS group. At the 9-12 month follow-up, 20% of patients in the FFR group had target-vessel-related myocardial ischemia, compared to 6% in the IVUS group. The rates of TVF and functional target vessel restenosis during follow-up were also numerically higher in the FFR optimization group.

CONCLUSIONS

The use of FFR PCI optimization strategy in the treatment of long coronary artery lesions is associated with a higher incidence of poor functional PCI result and larger myocardial ischemia burden at follow-up compared to the IVUS optimization strategy. However, this discrepancy did not translate into a statistically significant difference in clinical outcomes. This study highlights the importance of using IVUS to optimize long lesions functional PCI outcomes.

Clinical and Vessel Characteristics Associated With Hard Outcomes After PCI and Their Combined Prognostic Implications

Background Cardiac death or myocardial infarction still occurs in patients undergoing contemporary percutaneous coronary intervention (PCI). We aimed to identify adverse clinical and vessel characteristics related to hard outcomes after PCI and to investigate their individual and combined prognostic implications. Methods and Results From an individual patient data meta-analysis of 17 cohorts of patients who underwent post-PCI fractional flow reserve measurement after drug-eluting stent implantation, 2081 patients with available clinical and vessel characteristics were analyzed. The primary outcome was cardiac death or target-vessel myocardial infarction at 2 years. The mean age of patients was 64.2±10.2 years, and the mean angiographic percent diameter stenosis was 63.9%±14.3%. Among 11 clinical and 8 vessel features, 4 adverse clinical characteristics (age ≥65 years, diabetes, chronic kidney disease, and left ventricular ejection fraction <50%) and 2 adverse vessel characteristics (post-PCI fractional flow reserve ≤0.80 and total stent length ≥54 mm) were identified to independently predict the primary outcome (all P<0.05). The number of adverse vessel characteristics had additive predictability for the primary end point to that of adverse clinical characteristics (area under the curve 0.72 versus 0.78; P=0.03) and vice versa (area under the curve 0.68 versus 0.78; P=0.03). The cumulative event rate increased in the order of none, either, and both of adverse clinical characteristics ≥2 and adverse vessel characteristics ≥1 (0.3%, 2.4%, and 5.3%; P for trend <0.01). Conclusions In patients undergoing drug-eluting stent implantation, adverse clinical and vessel characteristics were associated with the risk of cardiac death or target-vessel myocardial infarction. Because these characteristics showed independent and additive prognostic value, their integrative assessment can optimize post-PCI risk stratification. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04684043. www.crd.york.ac.uk/prospero/. Unique Identifier: CRD42021234748.

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.

Validation of Segmental Post-PCI Physiological Gradients With IVUS-Detected Focal Lesions and Stent Underexpansion

BACKGROUND

Segmental post-percutaneous coronary intervention (PCI) pressure gradients may detect residual disease and potential targets for optimization. However, universal definitions of relevant segmental gradients are lacking.

OBJECTIVES

The study sought to evaluate the diagnostic performance of post-PCI fractional flow reserve (FFR), distal coronary pressure-to-aortic pressure ratio (Pd/Pa), and diastolic pressure ratio (dPR) gradients to detect residual focal lesions and stent underexpansion as observed by intravascular ultrasound (IVUS).

METHODS

Patients from the IVUS-guided optimization arm of the FFR REACT (FFR-guided PCI Optimization Directed by High-Definition IVUS Versus Standard of Care) trial with complete IVUS and FFR pullback data were included. Patients with angiographically successful PCI and post-PCI FFR <0.90 underwent FFR, Pd/Pa, and IVUS pullbacks. dPR was calculated offline using dedicated software. Segmental pressure gradients (distal, in stent, and proximal) in segments ≥5 mm were evaluated against IVUS-detected residual disease (distal or proximal focal lesions and stent underexpansion).

RESULTS

A total of 139 vessels were included (mean post-PCI FFR: 0.83 ± 0.05, range 0.56-0.89). Focal distal and proximal lesions were detected by IVUS in 23 (17.4%) of 132 and 14 (12.6%) of 111 vessels, respectively, whereas stent underexpansion was present in 86 (61.9%) vessels. Diagnostic ability of segmental FFR gradients to predict IVUS-detected distal and proximal lesions was moderate to good (area under the curve [AUC]: 0.69 and 0.84, respectively) and poor to moderate for segmental Pd/Pa and dPR gradients (AUC ranging from 0.58 to 0.69). In-stent gradients had no discriminative ability to detect stent underexpansion (FFR AUC: 0.52; Pd/Pa AUC: 0.54; dPR AUC: 0.55).

CONCLUSIONS

In patients with post-PCI FFR <0.90, segmental post-PCI pressure gradients have moderate discriminative ability to identify IVUS-detected focal lesions but no discriminative ability to identify IVUS-detected stent underexpansion.

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.

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).

Diagnostic accuracy of angiography‐based vessel fractional flow reserve after chronic coronary total occlusion recanalization

BACKGROUND

Angiography-based vessel fractional flow reserve (vFFR) demonstrated a strong correlation with invasive fractional flow reserve (FFR) in both a pre- and post-percutaneous coronary intervention (PCI) setting. However, the role of vFFR and its correlation with post-PCI FFR in chronic coronary occlusions (CTO) has not been evaluated yet. We sought to investigate the diagnostic performance of post-PCI vFFR with post-PCI FFR as a reference in patients undergoing successful CTO PCI.

METHODS

Between March 2016 and April 2020, a total of 80 patients from the FFR-SEARCH (prospective registry) and FFR REACT (randomized controlled trial) studies underwent successful CTO recanalization with post-PCI FFR measurements.

RESULTS

A total of 50 patients (median age 66 (interquartile range [IQR]: 56-74) years, 76% were male) were eligible for the analysis. Median post-PCI FFR was 0.89 (IQR: 0.84-0.94), while median post-PCI vFFR was 0.91 (IQR: 0.85-0.94) (p 0.10). Suboptimal physiological results, defined as FFR and vFFR <0.90, were identified in 26 (52%) and in 21 (42%) patients, respectively. A strong correlation (r = 0.82) was found between vFFR and FFR with a mean bias of 0.013 ± 0.051. Receiver-operating characteristics curve analysis revealed an excellent accuracy of vFFR in predicting FFR <0.90 (area under the curve: 0.97; 95% confidence interval: 0.93-1.00).

CONCLUSION

Post-PCI vFFR shows a good correlation with post-PCI FFR and a high diagnostic accuracy for post-PCI FFR ≤0.90 in patients undergoing successful PCI of a CTO lesion.