Patients undergoing percutaneous coronary intervention for acute coronary syndromes often have multivessel disease (MVD). Quantitative flow ratio (QFR) is an angiography-based technology that may help quantify the functional significance of non-culprit lesions, with the advantage that measurements are possible also once the patient is discharged from the catheterization laboratory.

Our two-center, randomized superiority trial aimed to test whether QFR, as compared to angiography, modifies the rate of non-culprit lesion interventions (primary functional endpoint) and improves the outcomes of patients with acute coronary syndromes and MVD (primary clinical endpoint).

In total, 202 consecutive patients (64 [56-71] years of age, 160 men) with STEMI (n = 69 (34%)), NSTEMI (n = 94 (47%)), or unstable angina (n = 39 (19%)) and MVD who had undergone successful treatment of all culprit lesions were randomized 1:1 to angiography- vs. QFR-guided delayed revascularization of 246 non-culprit stenoses (1.2/patient).

The proportion of patients assigned to percutaneous intervention was not different between groups (angiography group: 45 (45%) vs. QFR: 56 (55%), P = 0.125; relative risk = 0.80 (0.60-1.06)). At 12 months, a primary clinical endpoint event (composite of death, nonfatal myocardial infarction, revascularization, and significant angina) occurred in 24 patients (angiography-guided) and 23 patients (QFR-guided; P = 0.637, HR = 1.16 [0.63-2.15]). None of its components was different between groups.

QFR guidance based on analysis of images from the primary intervention was not associated with a difference in the rate of non-culprit lesion staged revascularization nor in the 12-month incidence of clinical events in patients with acute coronary syndromes and multivessel disease.

ClinicalTrials.gov Registry (NCT04808310).

Revascularisation decisions based on angiography-derived fractional flow reserve (FFR) or optimisation of stent implantation with intravascular ultrasound yield superior clinical outcomes compared with percutaneous coronary intervention (PCI) guided by angiography alone. However, the differences in outcomes when a single approach is used for both purposes remain unclear. We aimed to assess the non-inferiority of angiography-derived FFR versus intravascular ultrasound guidance in terms of clinical outcomes at 12 months in patients with angiographically significant stenosis.

This investigator-initiated, open-label, multicentre, randomised, non-inferiority trial, which was done in 22 centres in China, enrolled patients aged 18 years or older with suspected ischaemic heart disease and with at least 50% stenosis in epicardial coronary arteries measuring at least 2·5 mm by visual estimation on coronary angiography. Patients were randomly assigned (1:1) to undergo PCI guided by either angiography-derived FFR or intravascular ultrasound, including revascularisation decisions and optimisation of the stent implantations based on prespecified PCI criteria and optimal PCI goals. Use of both modalities simultaneously was not permitted. Randomisation as performed using a web-based program and stratified based on the trial centre and the presence or absence of diabetes. The primary outcome was a composite of death, myocardial infarction, or revascularisation at 12 months in the intention-to-treat population, and the non-inferiority margin was 2·5 percentage points. This trial is registered with ClinicalTrials.gov, NCT04397211; long-term follow-up is ongoing.

Between May 29, 2020, and Sept 20, 2023, 1872 patients were enrolled. After 33 patients withdrew, 923 patients were randomly assigned to the angiography-derived FFR group and 916 to the intravascular ultrasound group. Median age of the study population was 66·0 years (IQR 58·0-72·0), and 1248 (67·9%) patients were male and 591 (32·1%) were female. Revascularisation was performed in 688 (69·5%) of 990 target vessels in the angiography-derived FFR group and 797 (81·0%) of 984 target vessels in the intravascular ultrasound group. At a median follow-up of 12 months (IQR 12-12), the primary outcome event occurred in 56 patients in the angiography-derived FFR group and 54 patients in the intravascular ultrasound group (6·3% vs 6·0%, absolute difference 0·2 percentage points [upper boundary of one-sided 97·5% CI 2·4], pnon-inferiority=0·022; hazard ratio 1·04 [95% CI 0·71 to 1·51]). Mortality did not differ between the two groups (1·8% in the angiography-derived FFR group vs 1·3% in the intravascular ultrasound group, absolute difference 0·4 percentage points [95% CI -0·7 to 1·6]; hazard ratio 1·34 [0·63 to 2·83], p=0·45). The incidence of recurrent angina was low in both groups: 26 (2·8%) of 923 patients in the angiography-derived FFR group and 35 (3·8%) of 916 patients in the intravascular ultrasound group.

The angiography-derived FFR-guided comprehensive PCI strategy, encompassing revascularisation decision making and stent optimisation, was non-inferior to intravascular ultrasound guidance. This finding might have implications for future guidelines on its role and application.

National Natural Science Foundation of China, The Key R & D Projects of Zhejiang Province, and the RCT Program from The Second Affiliated Hospital of Zhejiang University School of Medicine.

The results of randomized clinical trials comparing the outcomes of different strategies for driving PCI are mixed, and it remains unclear which technique for driving PCI offers the greatest benefit. The aim of the study was to compare the clinical efficacy of different techniques to guide percutaneous coronary intervention (PCI).

We search major electronic databases for randomized clinical trials evaluating clinical outcomes of PCI with stent implantation guided by coronary angiography (CA), fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), intravascular ultrasound (IVUS) and optical coherence tomography (OCT). The primary outcome was cardiac death.

The results from 39 randomized trials (29,614 patients) were included in the network meta-analyses. Compared with CA, the use of OCT (RR: 0.33, 95 % CI: 0.19-0.54), IVUS (RR: 0.47, 95 % CI: 0.31-0.71) and FFR (RR: 0.61, 95 % CI: 0.38-0.97) were associated with reduced risk of cardiac death; there were no differences between OCT, IVUS and OCT was ranked as the best strategy. PCI guidance using OCT, FFR and IVUS was also associated with a reduction of myocardial infarction. The use of OCT or IVUS for PCI guidance was associated with a significant reduction in target lesion failure, target vessel revascularization, target lesion revascularization and stent thrombosis, compared with CA. OCT-guided PCI was associated with a significant reduction in all-cause death compared with CA-guided PCI and with a reduction in TLF compared with FFR- and iFR-guided PCI. Pooled estimates were mostly consistent across several sensitivity analyses.

Compared with angiography-guided PCI, both an intravascular imaging-guided strategy and a physiology-guided strategy are associated with better clinical outcomes.

Hemodynamically obstructive coronary plaques may contain more vulnerable plaque characteristics than nonobstructive lesions.

The authors aimed to assess whether pressure-wire-based physiologic indices in nonculprit lesions are associated with vulnerable plaque characteristics.

In the PROSPECT II study, patients with recent myocardial infarction underwent coronary angiography and culprit lesion percutaneous coronary intervention plus combined near-infrared spectroscopy and intravascular ultrasound assessment of all 3 coronary arteries. Instantaneous wave-free ratio (iFR) or fractional flow reserve (FFR) measurements were performed in intermediate lesions with angiographic stenosis >40%.

Among 898 patients, 319 angiographically intermediate lesions in 275 patients had matched intravascular ultrasound/near-infrared spectroscopy and FFR/iFR measurements; 96 (30.1%) lesions were physiologically significant (FFR ≤0.80 or iFR ≤0.89) and 223 (69.9%) were not. Physiologically significant lesions, compared with those that were not, more likely had a minimal lumen area ≤4.0 mm2 (96.9% vs 83.9%), plaque burden ≥70% (92.7% vs 71.3%) and maximum lipid core burden index in any 4 mm segment of the lesion ≥324.7 (57.0% vs 45.4%). By multivariable analysis, lesion location in the left anterior descending artery, small minimal lumen area, and larger plaque burden were independently associated with physiologic significance, whereas maximum lipid core burden index in any 4 mm segment of the lesion was not.

In patients with recent myocardial infarction, angiographically intermediate but physiologically significant coronary lesions were more likely to have high-risk vulnerable plaque features compared with nonphysiologically significant stenoses. However, coronary lesions without physiological significance also had a moderate-to-high prevalence of high-risk plaque characteristics, which may explain the residual risk associated with conservative noninterventional management of these lesions. (Providing Regional Observations to Study Predictors of Events in the Coronary Tree II [PROSPECT II]; NCT02171065).

Accurate discrimination of functionally significant coronary stenosis using intravascular imaging remains uncertain, particularly with regard to vessel size. This meta-analysis evaluates the diagnostic performance of intravascular ultrasound (IVUS) and optical coherence tomography (OCT) for identifying functionally significant coronary stenosis as confirmed by fractional flow reserve (FFR).

A systematic search of PubMed, Scopus and Google Scholar identified studies that assessed the diagnostic accuracy of IVUS and OCT by minimal luminal area (MLA) with FFR as the reference standard. Sensitivity and specificity were analysed across different vessel diameters including left main coronary artery (LM) lesions. Hierarchical models estimated the summary receiver operating characteristic curve, sensitivity and specificity.

31 studies involving 4039 patients and 4413 lesions were analysed. For IVUS, a median MLA threshold of 2.9 mm² (IQR: 2.6-3.2) predicted significant lesions, yielding an area under the curve (AUC) of 0.76. In vessels≥3 mm, this threshold increased to 3.0 mm² (IQR: 2.7-3.1) with an AUC of 0.76 while in smaller vessels it decreased to 2.6 mm² (IQR: 2.4-2.7) with an AUC of 0.79. For LM lesions, the median threshold was 6.0 mm² (IQR: 4.9-6.2) with an AUC of 0.88. OCT demonstrated a median threshold of 2.0 mm² (IQR: 1.7-2.3) and an AUC of 0.82 with better performance in larger vessels (≥3 mm, median 3.0 mm², AUC 0.87) than in smaller ones (<3 mm, median 1.8 mm², AUC 0.75).

IVUS and OCT show moderate diagnostic accuracy for identifying functionally significant coronary stenosis with OCT providing improved accuracy in vessels≥3 mm. IVUS is more accurate in assessing LM lesions, suggesting that vessel size should guide modality selection.

CRD 42024514538.

A recent randomised trial demonstrated fractional flow reserve (FFR) guidance for percutaneous coronary intervention (PCI) was non-inferior to intravascular ultrasound (IVUS) guidance regarding clinical outcomes, with a lower frequency of PCI.

We sought to evaluate the prognosis of FFR versus IVUS guidance for PCI of intermediate coronary artery stenosis and low lesion complexity in diabetic and non-diabetic patients.

This study is a prespecified post hoc analysis from the FLAVOUR trial. The primary outcome was major adverse cardiac events (MACE) at 24 months, defined as a composite of death, myocardial infarction or any revascularisation. The secondary outcomes were target vessel failure (TVF) and each component of MACE and TVF at 24 months.

Among 1,682 randomly assigned patients, 554 (32.9%) had diabetes, and the mean SYNTAX score was 8.64±6.03 at baseline. The FFR group had a lower PCI rate than the IVUS group in both diabetic (48.2% vs 69.1%; p<0.001) and non-diabetic (42.6% vs 63.3%; p<0.001) patients. At 24 months, there was no difference in the cumulative incidence of MACE between the FFR and the IVUS groups in either diabetic (9.3% vs 8.3%; p=0.90) or non-diabetic (7.5% vs 8.6%; p=0.50) patients. The cumulative incidence of TVF was also comparable between the FFR and the IVUS groups regardless of diabetic status.

In patients with intermediate coronary stenosis and low lesion complexity, regardless of diabetic status, FFR guidance had no significant differences in MACE or TVF with a lower frequency of PCI compared with IVUS guidance.

Complete non-culprit (NC) revascularisation may help reduce recurrent events after non-ST-segment elevation myocardial infarction (NSTEMI), especially if NC lesions would harbour high-risk plaque (HRP) features similar to ST-segment elevation myocardial infarction (STEMI). This study aimed to assess differences in fractional flow reserve (FFR)-negative NC plaque morphology in patients presenting with NSTEMI vs. STEMI and assess the association of HRP morphology and clinical outcome.

In the prospective PECTUS-obs study, 438 patients presenting with myocardial infarction (MI) underwent optical coherence tomography (OCT) of all FFR-negative intermediate NC lesions. The primary endpoint was the occurrence of major adverse cardiovascular events (MACE, composite of all-cause mortality, non-fatal MI or unplanned revascularisation) at 2-year follow-up. Four hundred and twenty patients had at least one analysable OCT, including 203 (48.3%) with NSTEMI and 217 (51.7%) with STEMI. The prevalence of HRPs, including thin-cap fibroatheromas, plaque rupture, and thrombus, was comparable between groups. MACE occurred in 29 (14.3%) NSTEMI patients and 16 (7.4%) STEMI patients (Puni-variable = 0.025 and Pmulti-variable = 0.270). Incidence of MACE was numerically higher among patients with HRP, irrespective of the clinical presentation at index (Pinteraction = 0.684). Among HRP criteria, plaque rupture was associated with MACE in both NSTEMI (P < 0.001) and STEMI (P = 0.020).

Presence of NC HRP is comparable between NSTEMI and STEMI and leads to numerically higher event rates in both. These results call for additional research on complete revascularisation in NSTEMI and treatment of HRP.

NCT03857971.

Recent randomized clinical trials have demonstrated the benefits of intravascular imaging (IVI)-guided percutaneous coronary intervention (PCI) over angiography-guided PCI. However, the role of angiography-based physiological assessment during IVI-guided PCI remains unclear.

This study aimed to explore the discrepancies and significance of angiography-based physiological assessments in IVI-guided PCI.

In the international multicenter randomized FLAVOUR (Fractional Flow Reserve and Intravascular Ultrasound for Clinical Outcomes in Patients With Intermediate Stenosis) trial, angiography-based physiological assessment was retrospectively performed using the Murray law-based quantitative flow ratio (μQFR). In this post hoc analysis, patients were categorized based on intravascular ultrasound (IVUS)-guided treatment decisions (PCI or deferral) and μQFR as follows: negative μQFR with deferral of PCI (DEFER), negative μQFR with PCI (PERFORM), and positive μQFR with PCI (REFERENCE). The primary outcome was major adverse cardiovascular events, defined as a composite of death, myocardial infarction, and target vessel revascularization at the 24-month follow-up.

Of the 784 patients, 34.4% (270/784), 29.3% (230/784), and 31.5% (247/784) were categorized into the DEFER, PERFORM, and REFERENCE groups, respectively. Physiological assessment led to substantial reclassification, encompassing 48.2% (230/477) of patients who underwent IVUS-guided PCI. The REFERENCE group showed a higher risk for major adverse cardiovascular events at 2 years compared with the PERFORM group (adjusted HR: 2.46; 95% CI: 1.13-5.35; P = 0.023). However, the primary outcomes in the DEFER and PERFORM groups were similar (adjusted HR: 0.88; 95% CI: 0.37-2.11; P = 0.779). The quality of life at 2 years was comparable among the 3 groups (P = 0.198).

Angiography-based physiological assessments can offer additional prognostic insights for patients undergoing IVI-guided PCI. IVUS-guided PCI may not be advantageous in patients with functionally insignificant lesions.

To evaluate the individual as well as combined impact of optical coherence tomography-detected vulnerability features (OCT-VFs) in the prediction of major adverse cardiovascular events (MACEs) in non-ischaemic lesions in patients with diabetes mellitus (DM).

The COMBINE OCT-FFR (NCT02989740) was a prospective, double-blind, international, natural-history study that included patients with DM having ≥1 lesions with a fractional flow reserve > 0.80, undergoing systematic OCT assessment. Pre-specified OCT-VFs included thin-cap fibroatheroma (TCFA), reduced minimal lumen area (r-MLA), high plaque burden (h-PB), and complicated plaque (CP). The primary endpoint (MACE) was a composite of cardiac mortality, target vessel myocardial infarction, clinically driven target lesion revascularization, or hospitalization for unstable angina up to 5 years, analysed according to the presence of these OCT-VFs, both individually and in combination. TCFA, r-MLA, h-PB, and CP were identified in 98 (25.1%), 159 (40.8%), 56 (14.4%), and 116 (29.8%) patients, respectively. The primary endpoint rate increased progressively from 6.9% to 50.0% (HR = 10.10; 95% CI, 3.37-30.25, P < 0.001) in patients without OCT-VFs compared with those with concomitant h-PB, r-MLA, CP, and TCFA. Importantly, while TCFA, h-PB, r-MLA, and CP were individually associated with the primary endpoint, the presence of two or more OCT-VFs significantly increased the likelihood of adverse events at 5 years.

In patients with DM and non-ischaemic lesions, TCFA, h-PB, r-MLA, and CP were predictors of adverse events. However, the presence of two or more OCT-VFs significantly increased the likelihood of MACE at 5 years. Further studies are warranted to confirm these findings and their potential clinical implications in a randomized fashion.

There is a paucity of data on the performance of angiography-derived vessel fractional flow reserve (vFFR) in coronary artery lesions of patients presenting with non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Optical coherence tomography (OCT) allows for visualization of lumen dimensions and plaque integrity with high resolution. The aim of this study was to define the association between vFFR and OCT findings in intermediate coronary artery lesions in patients presenting with NSTE-ACS.

The FAST OCT study was a prospective, multicenter, single-arm study. Patients presenting with NSTE-ACS with intermediate to severe coronary artery stenosis in one or multiple vessels with TIMI 3 flow suitable for OCT imaging were eligible. Complete pre-procedural vFFR and OCT data were available in 226 vessels (in 188 patients). A significant association between vFFR and minimal lumen area (MLA) was observed, showing an average decrease of 20.4% (95% CI -23.9% to -16.7%) in MLA per 0.10 decrease in vFFR (adjusted P < 0.001). vFFR ≤ 0.80 showed a sensitivity of 56.7% and specificity of 92.5% to detect MLA ≤ 2.5 mm2. Conversely, vFFR had a poor to moderate discriminative ability to detect plaque instability (sensitivity, 46.9%; specificity, 71.6%).

In patients with NSTE-ACS, vFFR is significantly associated with OCT-detected MLA, and vFFR ≤ 0.80 is highly predictive of the presence of significant disease based on OCT. Conversely, the sensitivity of vFFR ≤ 0.80 to detect OCT-assessed significant disease was low, indicating that the presence of significant OCT findings cannot be ruled out based on a negative vFFR.

Intravascular imaging has become an integral part of the diagnostic and management strategies for intracoronary pathologies. In this White Paper we summarize current evidence and its implications on the use of intravascular imaging in interventional cardiology practice. The areas addressed are planning and optimization of percutaneous coronary intervention, management of stent failure, and evaluation of ambiguous coronary lesions and myocardial infarction with nonobstructive coronary disease. The findings presented followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system in an expert consensus process that involved a diverse writing group vetted by a review group. Expert consensus was achieved around 9 statements. Use of intravascular imaging in guiding percutaneous revascularization is supported by high-quality evidence, particularly for lesions with increased risk of recurrent events or stent failure. Specific considerations for intravascular imaging guidance of intervention in left main lesions, chronic occlusion lesions, and in patients at high risk of contrast nephropathy are explored. Use of intravascular imaging to identify pathologies associated with stent failure and guide repeat intervention, resolve ambiguities in lesion assessment, and establish diagnoses in patients who present with myocardial infarction with nonobstructive coronary disease is supported by moderate- to low-quality evidence. Each topic is accompanied by clinical pointers to aid the practicing interventional cardiologist in implementation of the White Paper findings. The findings presented in this White Paper will help to guide the use of intravascular imaging toward situations in which the balance of efficacy, safety, and cost are most optimal.

Functional coronary angiography (FCA) is a novel modality for assessing the physiology of coronary lesions, going beyond anatomical visualization by traditional coronary angiography. FCA incorporates indices like fractional flow reserve (FFR) and instantaneous wave-free ratio (IFR), which utilize pressure measurements across coronary stenoses to evaluate hemodynamic impacts and to guide revascularization strategies. In this review, we present traditional and evolving modalities and uses of FCA. We will also evaluate the existing evidence and discuss the applicability of FCA in various clinical scenarios. Finally, we provide insight into emerging evidence, current challenges, and future directions in FCA.

This Perspective article is a form of 'pastiche', inspired by the 1993 review by Lincoff and Topol entitled 'Illusion of reperfusion', and explores how their concept continues to apply to percutaneous revascularization in patients with coronary artery disease and ischaemia. Just as Lincoff and Topol argued that reperfusion of acute myocardial infarction was facing unresolved obstacles that hampered clinical success in 1993, we propose that challenging issues are similarly jeopardizing the potential benefits of stent-based angioplasty today. By analysing the appropriateness and efficacy of percutaneous coronary intervention (PCI), we emphasize the limitations of relying solely on visual angiographic guidance, which frequently leads to inappropriate stenting and overtreatment in up to one-third of patients and the associated increased risk of periprocedural myocardial infarction. The lack of optimal revascularization observed in half of patients undergoing PCI confers risks such as suboptimal physiology after PCI, residual angina and long-term stent-related events, leaving an estimated 76% of patients with an 'illusion of revascularization'. These outcomes highlight the need to refine our diagnostic tools by integrating physiological assessments with targeted intracoronary imaging and emerging strategies, such as co-registration systems and angiography-based computational methods enhanced by artificial intelligence, to achieve optimal revascularization outcomes.

Multivessel coronary artery disease (CAD), defined as ≥50% stenosis in 2 or more epicardial arteries, is associated with a high burden of morbidity and mortality in acute coronary syndrome (ACS) patients. A salient challenge for managing this cohort is selecting the optimal revascularisation strategy, for which the use of coronary physiology has been increasingly recognised. Fractional flow reserve (FFR) is an invasive, pressure wire-based, physiological index measuring the functional significance of coronary lesions. Understanding this can help practitioners evaluate which lesions could induce myocardial ischaemia and, thus, decide which vessels require urgent revascularisation. Non-hyperaemic physiology-based indices, such as instantaneous wave-free ratio (iFR), provide valid alternatives to FFR. While FFR and iFR are recommended by international guidelines in stable CAD, there is ongoing discussion regarding the role of physiology in patients with ACS and multivessel disease (MVD); growing evidence supports FFR use in the latter. Compelling findings show FFR-guided complete percutaneous coronary intervention (PCI) can reduce adverse cardiovascular events, mortality, and repeat revascularisations in ACS and MVD patients compared to angiography-based PCI. However, FFR is limited in identifying non-flow-limiting vulnerable plaques, which can disadvantage high-risk patients. Here, integrating coronary physiology assessment with intracoronary imaging in decision-making can improve outcomes and quality of life. Further research into novel physiology-based tools in ACS and MVD is needed. This review aims to highlight the key evidence surrounding the role of FFR and other functional indices in guiding PCI strategy in ACS and MVD patients.

Fractional flow reserve (FFR) represents the gold standard in guiding the decision to proceed or not with coronary revascularization of angiographically intermediate coronary lesion (AICL). Optical coherence tomography (OCT) allows to carefully characterize coronary plaque morphology and lumen dimensions.

We sought to develop machine learning (ML) models based on clinical, angiographic and OCT variables for predicting FFR.

Data from a multicenter, international, pooled analysis of individual patient's level data from published studies assessing FFR and OCT on the same target AICL were collected through a dedicated database to train (n = 351) and validate (n = 151) six two-class supervised ML models employing 25 clinical, angiographic and OCT variables.

A total of 502 coronary lesions in 489 patients were included. The AUC of the six ML models ranged from 0.71 to 0.78, whereas the measured F1 score was from 0.70 to 0.75. The ML algorithms showed moderate sensitivity (range: 0.68-0.77) and specificity (range: 0.59-0.69) in detecting patients with a positive or negative FFR. In the sensitivity analysis, using 0.75 as FFR cut-off, we found a higher AUC (0.78-0.86) and a similar F1 score (range: 0.63-0.76). Specifically, the six ML models showed a higher specificity (0.71-0.84), with a similar sensitivity (0.58-0.80) with respect to 0.80 cut-off.

ML algorithms derived from clinical, angiographic, and OCT parameters can identify patients with a positive or negative FFR.

Angiographic assessment of coronary stenosis severity using quantitative coronary angiography (QCA) is often inconsistent with that based on fractional flow reserve (FFR) or intravascular ultrasound (IVUS). We investigated the incidence of discrepancies between QCA and FFR or IVUS, and the outcomes of FFR- and IVUS-guided strategies in discordant coronary lesions.

This study was a post-hoc analysis of the FLAVOUR study. We used a QCA-derived diameter stenosis (DS) of 60% or greater, the highest tertile, to classify coronary lesions as concordant or discordant with FFR or IVUS criteria for percutaneous coronary intervention (PCI). The patient-oriented composite outcome (POCO) was defined as a composite of death, myocardial infarction, or revascularization at 24 months.

The discordance rate between QCA and FFR or IVUS was 30.2% (n=551). The QCA-FFR discordance rate was numerically lower than the QCA-IVUS discordance rate (28.2% vs. 32.4%, p=0.050). In 200 patients with ≥60% DS, PCI was deferred according to negative FFR (n=141) and negative IVUS (n=59) (15.3% vs. 6.5%, p<0.001). The POCO incidence was comparable between the FFR- and IVUS-guided deferral strategies (5.9% vs. 3.4%, p=0.479). Conversely, 351 patients with DS <60% underwent PCI according to positive FFR (n=118) and positive IVUS (n=233) (12.8% vs. 25.9%, p<0.001). FFR- and IVUS-guided PCI did not differ in the incidence of POCO (9.5% vs. 6.5%, p=0.294).

The proportion of QCA-FFR or IVUS discordance was approximately one third for intermediate coronary lesions. FFR- or IVUS-guided strategies for these lesions were comparable with respect to POCO at 24 months.

ClinicalTrials.gov Identifier: NCT02673424.

Background: Due to its high resolution, optical coherence tomography (OCT) is the most suitable modality for neointimal coverage assessments. Evaluation of stent healing seems crucial to accurately define their safety profile since delayed healing is connected with stent thrombosis. This study aimed to present an algorithm for automated quantitative analysis of stent strut coverage at the early stages of vessel healing in intravascular OCT. Methods: A set of 592 OCT frames from 24 patients one month following drug-eluting stent implantation was used to assess the algorithm's effectiveness. Struts not covered on any side or covered but only on one side were categorized as uncovered. The algorithm consists of several key steps: preprocessing, vessel lumen segmentation, automatic strut detection, and measurement of neointimal thickness. Results: The proposed algorithm proved its efficiency in lumen and stent area estimation versus manual reference. It showed a high positive predictive value (PPV) (89.7%) and true positive rate (TPR) (91.4%) in detecting struts. A qualitative assessment for covered and uncovered struts was characterized by high TPR (99.1% and 80%, respectively, for uncovered and covered struts) and PPV (77.3% and 87%). Conclusions: The proposed algorithm demonstrated good agreement with manual measurements. Automating the stent coverage assessment might facilitate imaging analysis, which might be beneficial in experimental and clinical settings.

Evidence regarding the comparative efficacy of the different methods to determine the significance of coronary stenoses in the catheterization laboratory is lacking. We aimed to compare all available methods guiding the decision to perform percutaneous coronary intervention (PCI). We searched Medline, Embase, and CENTRAL until October 5, 2023. We included trials that randomized patients with greater than 30% stenoses who were considered for PCI and reported major adverse cardiovascular events (MACE). We performed a frequentist random-effects network meta-analysis and assessed the certainty of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. We included 15 trials with 16,333 participants with a mean weighted follow-up of 34 months. The trials contained a median of 49.3% (interquartile range: 32.6%, 100%) acute coronary syndrome participants. Quantitative flow ratio (QFR) was associated with a decreased risk of MACE compared with coronary angiography (CA) (risk ratio [RR] 0.68, 95% confidence interval [CI] 0.56 to 0.82, high certainty), fractional flow reserve (FFR) (RR 0.73, 95% CI 0.58 to 0.92, moderate certainty), and instantaneous wave-free ratio (iFR) (RR 0.63, 95% CI 0.49 to 0.82, moderate certainty), and ranked first for MACE (88.1% probability of being the best). FFR (RR 0.93, 95% CI 0.82 to 1.06, moderate certainty) and iFR (RR 1.07, 95% CI 0.90 to 1.28, moderate certainty) likely did not decrease the risk of MACE compared with CA. Intravascular imaging may not be associated with a significant decrease in MACE compared with CA (RR 0.85, 95% CI 0.62 to 1.17, low certainty) when used to guide the decision to perform PCI. In conclusion, a decision to perform PCI based on QFR was associated with a decreased risk of MACE compared with CA, FFR, and iFR in a mixed stable coronary disease and acute coronary syndrome population. These hypothesis-generating findings should be validated in large, randomized, head-to-head trials.

Functional assessment using fractional flow reserve (FFR) and anatomical assessment using optical coherence tomography (OCT) are used in clinical practice for patients with intermediate coronary stenosis. Moreover, coronary computed tomography angiography (CTA) is a common noninvasive imaging technique for evaluating suspected coronary artery disease before being referred for angiography. This study aimed to investigate the association between FFR and plaque characteristics assessed using coronary CTA and OCT for intermediate coronary stenosis.

Based on a prospective multicenter registry, 159 patients having 339 coronary lesions with intermediate stenosis were included. All patients underwent coronary CTA before being referred for coronary angiography, and both FFR measurements and OCT examinations were performed during angiography. A stenotic lesion identified with FFR ≤0.80 was deemed diagnostic of an ischemia-causing lesion. The predictive value of plaque characteristics assessed using coronary CTA and OCT for identifying lesions causing ischemia was analyzed.

Stenosis severity and plaque characteristics on coronary CTA and OCT differed between lesions that caused ischemia and those that did not. In multivariate analysis, low attenuation plaque on coronary CTA (odds ratio [OR]=2.78; P=0.038), thrombus (OR=5.13; P=0.042), plaque rupture (OR=3.25; P=0.017), and intimal vasculature on OCT (OR=2.57; P=0.012) were independent predictors of ischemic lesions. Increasing the number of these plaque characteristics offered incremental improvement in predicting the lesions causing ischemia.

Comprehensive anatomical evaluation of coronary stenosis may provide additional supportive information for predicting the lesions causing ischemia.

The FORZA trial (FFR or OCT Guidance to Revascularize Intermediate Coronary Stenosis Using Angioplasty) prospectively compared the use of fractional flow reserve (FFR) or optical coherence tomography (OCT) for treatment decisions and percutaneous coronary intervention (PCI) optimization in patients with angiographically intermediate coronary lesions. Murray law-based quantitative-flow-ratio (μQFR) is a novel noninvasive method for the computation of FFR. In the present study, we evaluated the clinical impact of μQFR, FFR, or OCT guidance in FORZA trial lesions at 3-year follow-up.

μQFR was assessed at baseline and, in the case of a decision to intervene, after (FFR- or OCT-guided) PCI. The baseline μQFR was considered the final μQFR for deferred lesions, and post-PCI μQFR value was taken as final for stented lesions. The primary end point was target vessel failure ([TVF]; cardiac death, target-vessel-related myocardial infarction, and target-vessel-revascularization) at a 3-year follow-up.

A total of 419 vessels (199 OCT-guided and 220 FFR-guided) were included in the FORZA trial. μQFR was evaluated in 256 deferred lesions and 159 treated lesions (98 OCT-guided PCI and 61 FFR-guided PCI). In treated lesions, post-PCI μQFR was higher in OCT-group compared with FFR-group (median, 0.93 versus 0.91; P=0.023), and the post-PCI μQFR improvement was greater in FFR-group (0.14 versus 0.08; P<0.0001). At 3-year follow-up, OCT- and FFR-guided treatment decisions resulted in comparable TVF rate (6.7% versus 7.9%; P=0.617). Final μQFR was the only predictor of TVF. μQFR ≤0.89 was associated with 3× increase in TVF (11.6% versus 3.7%; P=0.004). PCI was a predictor of higher final μQFR (odds ratio, 0.22 [95% CI, 0.14-0.34]; P<0.001).

In vessels with angiographically intermediate coronary lesions, OCT-guided PCI resulted in comparable clinical outcomes as FFR-guided PCI. μQFR estimated at the end of diagnostic or interventional procedure predicted 3-year TVF.

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01824030.

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.

Optical coherence tomography (OCT) allows to carefully characterize coronary plaque morphology and lumen dimensions. We sought to evaluate the value of OCT in predicting fractional flow reserve (FFR).

We performed a multicenter, international, pooled analysis of individual patient-level data from published studies assessing FFR and OCT on the same vessel. Data from stable or unstable patients who underwent both FFR and OCT of the same coronary artery were collected through a dedicated database. Predefined OCT parameters were minimum lumen area (MLA), percentage area stenosis (%AS), and presence of thrombus or plaque rupture. Primary end point was FFR ≤0.80. Secondary outcome was the incidence of major adverse cardiac events in patients not undergoing revascularization based on negative FFR (>0.80).

A total of 502 coronary lesions in 489 patients were included. A significant correlation was observed between OCT-MLA and FFR values (R = 0.525; P < .001), and between OCT-%AS and FFR values (R = -0.482; P < .001). In Receiver operating characteristic analysis, MLA <2.0 mm2 showed a good discriminative power to predict an FFR ≤0.80 (AUC, 0.80), whereas %AS >73% showed a moderate discriminative power (AUC, 0.73). When considering proximal coronary segments, the best OCT cutoff values predicting an FFR ≤0.80 were MLA <3.1 mm2 (AUC, 0.82), and %AS >61% (AUC, 0.84). In patients with a negative FFR not revascularized, the combination of lower MLA and higher %AS had a trend toward worse outcome (which was statistically significant in the analysis restricted to proximal vessels).

OCT lumen measures (MLA, %AS) may predict FFR, and different cutoffs are needed for proximal vessels.

The proportion of patients with multivessel coronary artery disease in individuals experiencing acute coronary syndrome (ACS) varies based on age and ACS subtype. In patients with ST-segment elevation myocardial infarction (STEMI) without cardiogenic shock, the prognostic benefit of complete revascularization has been demonstrated by several randomized trials and meta-analyses, leading to a strong guideline recommendation. However, similar data are lacking for ACS without ST-segment elevation (NSTE-ACS). Non-randomized data suggesting a benefit from complete revascularization in non-ST-segment elevation myocardial infarction (NSTEMI) are prone to selection bias and should be interpreted with caution. A series of large randomized controlled trials have been initiated recently to address these open questions.