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To evaluate the impact of coronary artery disease (CAD), percutaneous coronary intervention (PCI), and coronary lesion complexity on outcomes of transcatheter aortic valve replacement (TAVR) for aortic stenosis. This retrospective study included 1042 patients divided into two groups by the presence or absence of CAD (SYNTAX score 0, no history of revascularization). Propensity score matching was used to compare the two groups. The effect of PCI, SYNTAX score, and residual SYNTAX score was also analyzed. The median age of the cohort was 82 years, and 641 patients had CAD. After propensity score matching, 346 pairs were analyzed. During 5 years of follow-up (median: 25, range 0–72 months), the rate of coronary intervention was significantly higher in CAD patients (p = 0.018). However, all-cause mortality, composite of all-cause mortality, stroke, and coronary intervention, and overt bleeding defined by VARC-3 were comparable. After stratification, in patients with creatinine ≥1.5 mg/dl, CAD was associated with a worse composite outcome (p = 0.016). Neither PCI nor SYNTAX score was associated with all-cause mortality in CAD patients. Similarly, residual SYNTAX score showed no association with mortality in patients undergoing PCI (all p values >0.7). PCI did not reach a significant difference in overt bleeding in CAD patients (adjusted p = 0.06). Despite a higher incidence of coronary interventions, major clinical outcomes were similar between patients with and without CAD after TAVR. In patients with chronic kidney disease, CAD may be associated with an adverse composite outcome. Neither PCI nor SYNTAX/residual SYNTAX score influenced all-cause mortality. • The impact of Coronary artery disease (CAD), PCI, and SYNTAX score on TAVR. • Higher incidence of coronary intervention after TAVR in patients with CAD. • Otherwise comparable outcomes between CAD and no CAD patients up to 5 years • Possible worse clinical outcome of CAD in patients with CKD. • No effect of PCI or SYNTAX/residual SYNTAX score on mortality after TAVR. [ABSTRACT FROM AUTHOR]

Background: Diagnosing myocardial ischemia in chronic kidney disease (CKD) patients is crucial since coronary artery disease (CAD) forms the predominant cause of mortality in these patients. Thus, this study aimed to assess the impact of kidney function on the results of coronary circulation physiological assessment. Methods: Data were collected from 279 consecutive patients admitted to the Clinical Department of Cardiology and Cardiovascular Interventions at the University Hospital in Krakow. A total of 417 vessels were assessed for fractional flow reserve (FFR) and non-hyperemic resting pressure ratios, such as instantaneous wave-free ratio (iFR) and resting full-cycle ratio (RFR). Patients were categorized into two groups: glomerular filtration rate (GFR)-L (estimated GFR (eGFR) <70 mL/min/1.73 m² ) and GFR-H (eGFR ≥70 mL/min/1.73 m²). Results: A total of 118 patients (42.3%) were included in the GFR-L group, while 161 patients (57.7%) were in the GFR-H group. The left anterior descending branch of the left coronary artery (LAD) was the assessed vessel in approximately 60% of procedures, the frequency of which was very similar in both study groups. Focusing solely on LAD assessments, both FFR metrics (continuous and binary) were comparable between the groups. In contrast, for non-LAD vessels, the GFR-H group revealed substantially reduced FFR values, with more vessels displaying significant constriction. Patients in the GFR-H group showed higher instances of FFR+ | iFR/RFR- discrepancies than their lower eGFR counterparts. An eGFR of 70 mL/min/1.73 m 2 was the optimal cut-off to differentiate patients concerning the mentioned discrepancies. Conclusions: Kidney function influenced the coronary circulation physiological assessment results. Patients with reduced eGFR tended to have negative hyperemic assessments, especially in non-LAD vessels. [ABSTRACT FROM AUTHOR]

Despite guideline-based recommendation of the interchangeable use of instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) to guide revascularization decision-making, iFR/FFR could demonstrate different physiological or clinical outcomes in some specific patient or lesion subsets. Therefore, we sought to investigate the impact of difference between iFR and FFR-guided revascularization decision-making on clinical outcomes in patients with left main disease (LMD). In this international multicenter registry of LMD with physiological interrogation, we identified 275 patients in whom physiological assessment was performed with both iFR/FFR. Major adverse cardiovascular event (MACE) was defined as a composite of death, non-fatal myocardial infarction, and ischemia-driven target lesion revascularization. The receiver-operating characteristic analysis was performed for both iFR/FFR to predict MACE in respective patients in whom revascularization was deferred and performed. In 153 patients of revascularization deferral, MACE occurred in 17.0% patients. The optimal cut-off values of iFR and FFR to predict MACE were 0.88 (specificity:0.74; sensitivity:0.65) and 0.76 (specificity:0.81; sensitivity:0.46), respectively. The area under the curve (AUC) was significantly higher for iFR than FFR (0.74; 95%CI 0.62–0.85 vs. 0.62; 95%CI 0.48–0.75; p = 0.012). In 122 patients of coronary revascularization, MACE occurred in 13.1% patients. The optimal cut-off values of iFR and FFR were 0.92 (specificity:0.93; sensitivity:0.25) and 0.81 (specificity:0.047; sensitivity:1.00), respectively. The AUCs were not significantly different between iFR and FFR (0.57; 95%CI 0.40–0.73 vs. 0.46; 95%CI 0.31–0.61; p = 0.43). While neither baseline iFR nor FFR was predictive of MACE in patients in whom revascularization was performed, iFR-guided deferral seemed to be safer than FFR-guided deferral. Impact of Physiological Assessment with iFR and FFR on Clinical Outcomes of Patients with LMD. In the present study, physiological assessment, both with iFR and FFR, provided a high predictability of adverse cardiovascular event in LMD patients with revascularization deferral. Furthermore, the iFR-guided deferral strategy was safer as compared to FFR. Conversely, in patients in whom revascularization was performed for LMD, neither iFR nor FFR was predictive of cardiovascular event. AUC: area under the curve; FFR: fractional flow reserve; iFR: instantaneous wave-free ratio; LMD: left main coronary artery disease. [ABSTRACT FROM AUTHOR]

This article reviews four new technologies for assessment of coronary hemodynamics based on medical imaging and artificial intelligence, including quantitative flow ratio (QFR), optical flow ratio (OFR), computational fractional flow reserve (CT-FFR) and artificial intelligence (AI)-based instantaneous wave-free ratio (iFR). These technologies use medical imaging such as coronary angiography, computed tomography angiography (CTA), and optical coherence tomography (OCT), to reconstruct three-dimensional vascular models through artificial intelligence algorithms, simulate and calculate hemodynamic parameters in the coronary arteries, and achieve noninvasive and rapid assessment of the functional significance of coronary stenosis. This article details the working principles, advantages such as non-invasiveness, efficiency, accuracy, limitations such as image dependency, and assumption restrictions, of each technology. It also compares and analyzes the image dependency, calculation accuracy, calculation speed, and operation simplicity, of the four technologies. The results show that these technologies are highly consistent with the traditional invasive wire method, and shows distinct advantages in terms of accuracy, reliability, convenience and cost-effectiveness, but there are also factors that affect accuracy. The results of this review demonstrates that AI-based iFR technology is currently one of the most promising technologies. The main challenges and directions for future development are also discussed. These technologies bring new ideas for the non-invasive assessment of coronary artery disease, and are expected to promote the technological progress in this field. [ABSTRACT FROM AUTHOR]

Coronary artery disease (CAD) is one of the main causes of death in the world. Functional indices such as fractional flow reserve (FFR), coronary flow reserve (CFR) and instantaneous wave-free ratio (iFR) are used to estimate the severity of CAD. Approximately 30–50% of patients have residual myocardial ischaemia even after formally successful percutaneous coronary intervention (PCI). Myocardial perfusion impairment is one of the main factors responsible for recurrence. We propose a novel 1D model of coronary hemodynamics that takes into account myocardial contraction, stenoses and impaired microcirculation. It uses non-invasively acquired data. The model is able to simulate FFR and iFR with a mean relative error of 3% and a standard mean deviation of 0.04. We find that healthy FFR and iFR values in the short and long term do not always correspond to healthy CFR values and recovery of coronary blood flow. We also show that PCI of stenosis also improves hemodynamic indices in adjacent stenosed vessels, with a more pronounced effect in the long term. [ABSTRACT FROM AUTHOR]

It is unclear whether coronary physiology or coronary angiography (CA)-guided strategy is the more preferable approach for deferring percutaneous coronary intervention (PCI). We sought to evaluate the clinical efficacy of various PCI strategies through a network meta-analysis of randomized controlled trials (RCTs). We searched multiple databases for RCTs investigating the impact of the following strategies for the purpose of determining whether or not to defer PCI: fractional flow reserve, instantaneous wave-free ratio, quantitative flow ratio (QFR), and CA. We conducted a network meta-analysis for trial-defined major adverse cardiovascular events (MACE), all-cause death, cardiovascular death, myocardial infarction (MI), target lesion revascularization (TLR), and stent thrombosis. We performed a subgroup analysis for those with acute coronary syndrome (ACS). Our search identified 12 eligible RCTs including a total of 13,177 patients. QFR-guided PCI was associated with reduced MACE, MI, and TLR compared with CA-guided PCI (relative risk (RR) 0.68; 95 % confidence interval (CI] [0.49 to 0.94], RR 0.58; 95 % CI [0.36 to 0.96], and RR 0.58; 95 % CI [0.38 to 0.91], respectively). There were no significant differences in any pairs for all-cause death, cardiovascular death, or stent thrombosis. QFR was ranked the best in most outcomes. In the subgroup analysis of the ACS cohort, there were no significant differences in MACE between any comparisons. QFR was associated with reduced MACE, MI, and TLR compared with CA, and ranked the best in most outcomes. However, this was not applied in the ACS cohort. • QFR was associated with reduced MACE, MI, and TLR compared with CA. • QFR was ranked the best in most outcomes among physiology-guided strategies. • The superiority of QFR was not observed in the ACS cohort. [ABSTRACT FROM AUTHOR]

Background: Diagnosing myocardial ischemia in chronic kidney disease (CKD) patients is crucial since coronary artery disease (CAD) forms the predominant cause of mortality in these patients. Thus, this study aimed to assess the impact of kidney function on the results of coronary circulation physiological assessment. Methods: Data were collected from 279 consecutive patients admitted to the Clinical Department of Cardiology and Cardiovascular Interventions at the University Hospital in Krakow. A total of 417 vessels were assessed for fractional flow reserve (FFR) and non-hyperemic resting pressure ratios, such as instantaneous wave-free ratio (iFR) and resting full-cycle ratio (RFR). Patients were categorized into two groups: glomerular filtration rate (GFR)-L (estimated GFR (eGFR)

As technology improves, the number of transcatheter aortic valve implantation (TAVI) procedures performed is steadily increasing. Due to the comparable outcomes with surgical treatment of aortic stenosis, TAVI is increasingly being performed in a group of younger patients. In this connection, there is an increasing need for a reasonable approach to assessing the severity of concomitant coronary lesions. Non-invasive studies in this group of patients have low sensitivity and specificity in identifying significant coronary narrowing. In addition, the use of stress testing is limited by the risks of potential complications due to the severity of patients with critical aortic stenosis. The assessment of fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR), which has become widespread in isolated coronary heart disease (CAD), in the case of a combination of CAD with aortic stenosis, requires careful study and analysis. The literature review shows that today there are the first results of using the assessment of coronary physiology to determine indications for myocardial revascularization in patients with aortic stenosis. New threshold values of FFR and iFR applicable for patients in this group are considered. The results of literature data indicate the need for large randomized studies to better understand the method capabilities and develop the most optimal approach to the treatment of TAVI candidates with concomitant CAD.

Background: The application of fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) in multivessel coronary artery disease (CAD) patients has not been definitively explored. We herein assessed how treatment strategies were decided based on FFR/iFR values in vessels selected clinically. Specifically, we sought to determine whether treatment selection was based on whether the vessel tested was the clinical target stenosis. Methods: 270 consecutive patients with angiographically determined multivessel disease who underwent FFR/iFR testing were included. Patients were classified initially based on their angiographic findings, then re-evaluated from FFR/iFR results (normal or abnormal). Tested lesions were classified into target or non-target lesions based on clinical and non-invasive evaluations. Results: Abnormal FFR/iFR values were demonstrated in 51.9 % of patients, in whom 51.4 % received coronary stenting (PCI) and 44.3 % had bypass surgery (CABG). With two-vessel CAD patients, medical therapy was preferred when the target lesion was normal (72.6 %), while PCI was preferred when it was abnormal (78.4 %). In non-target lesions, PCI was preferred regardless of FFR/iFR results (78.0 %). With three-vessel CAD patients, CABG was preferred when the target lesion was abnormal (68.5 %), and there was no difference in the selected modality when it was normal. Furthermore, the incidence of tested lesions was higher in the left anterior descending (LAD) compared to other coronary arteries, and two-vessel CAD patients with LAD stenoses were more frequently treated by PCI. Conclusion: The use of invasive physiologic testing in multivessel CAD patients may alter the preferred treatment strategy, leading to an overall increase in PCI selection.

Aortic stenosis (AS) combined with coronary artery disease (CAD) is very common in clinical practice. Transcatheter aortic valve implantation (TAVI) is an effective clinical treatment for AS. Due to the advantages of less trauma and faster recovery, the clinical application of TAVI has become more and more extensive. However, after TAVI, coronary angiography and percutaneous coronary intervention (PCI) may become difficult due to the valve frame or the patients valve. Meanwhile, acute occlusion of the coronary arteries may be caused during TAVI with severe consequences in a small number of patients because of the structures surrounding the aortic valve and coronary artery openings. Clinically, the management of CAD in patients undergoing TAVI has not been taken seriously. In addition, treatment evidence and recommendations are not uniform. Therefore, this consensus analyzes and reviews the evidence on the impact of CAD on the prognosis of patients undergoing TAVI, the implementation of PCI in patients undergoing TAVI, and the conduct of coronary artery protective measures during TAVI, with the aim of providing valuable recommendations for clinical practice.

Aim. To analyze the use in clinical practice of intravascular coronary assessment methods based on two-year data from the Russian Registry on the Use of Intravascular Imaging and Physiology.Material and methods. Since 2021, the Russian Registry on the Use of Intravascular Imaging and Physiology has included data from 7967 studies in 3932 patients, of which 3086 (38,7%) were studies of intravascular physiology. In 2021, 13 branches from 9 cities participated in the registry, in 2022 — 20 branches from 11 cities. For chronic coronary artery disease, 2484 (80,5%) studies were performed, for acute coronary syndrome (ACS) — 598 (19,4%).Results. In 2022, the registry included 1,9 times more intravascular functional studies compared to 2021. The contribution of different clinics was uneven — 75,7% of studies were performed in three departments. The use of non-hyperemic indexes prevailed over hyperemic ones (58%), and in ACS they were used three times more often. All coronary arteries were examined, most often the anterior descending artery. As a primary diagnosis, 1968 (63,8%) studies were performed, while for the purpose of dynamic control — 122 (3,9%), at the surgical stage — 996 (32,3%). In 85,5% (n=2638) of observations, the functional assessment of stenosis hemodynamic significance directly influenced the treatment tactics.Conclusion. The registry data indicate the significant role of functional methods among intravascular diagnostic options in the practice of domestic clinics participating in the registry. The registry demonstrated their use as a primary diagnosis 2 times more often than for coronary artery stenting. Some indications for the active use of intravascular physiology methods (in acute coronary syndrome, left coronary artery involvement) are currently controversial and require further research.

ObjectiveFractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are invasive methods to assess the functional significance of intermediate severity coronary lesions. Both indexes have been extensively validated in clinical trials in guiding revascularisation in patients with stable ischaemic heart disease undergoing percutaneous coronary intervention (PCI) with improved clinical outcomes. However, the role of these tools in coronary artery bypass grafting (CABG) is less clear.MethodsA meta-analysis of randomised trials and observational studies was carried out to help in determining the optimal strategy for assessing lesion severity and selecting graft targets in patients undergoing CABG. Electronic searches were carried out on Embase, MEDLINE, and Web of Science. A group of four authors independently screened and then assessed the retrieved records. Cochrane's Risk of Bias and Robins-I tools were used for bias assessment. A survey was conducted among surgeons and cardiologists to describe current attitudes towards the preoperative use of functional coronary investigations in practice.ResultsClinical outcomes including mortality at 30 days, perioperative myocardial infarction, number of grafts, incidence of stroke, rate of further need for revascularisation, and patient-reported quality of life did not differ in CABG guided by functional testing from those guided by traditional angiography.The survey revealed that in half of the surgical and cardiology units functional assessment is performed in CABG patients; there is a general perception that functional testing has improved patient care and its use would clarify the role of moderate coronary lesions that often need multidisciplinary rediscussions; moderate stenosis are felt to be clinically relevant; and anatomical considerations need to be taken into account together with functional assessment.ConclusionsAt present, the evidence to support the routine use of functional testing in intermediate lesions for planning CABG is currently insufficient. The pooled data currently available do not show an increased risk in mortality, myocardial injury, and stroke in the FFR/iFR-guided group. Further trials with highly selected populations are needed to clarify the best strategy.Systematic Review RegistrationClinicalTrials.gov, identifier (CRD42023414604).

In patients undergoing percutaneous coronary intervention (PCI), it remains unclear whether intravascular imaging guidance or functional guidance is the best strategy to optimize outcomes and if the results are different in patients with vs without acute coronary syndromes (ACS). The purpose of this study was to evaluate clinical outcomes with imaging-guided PCI or functionally guided PCI when compared with conventional angiography-guided PCI. We searched PUBMED and EMBASE for randomized controlled trials investigating outcomes with intravascular imaging-guided, functionally guided, or angiography-guided PCI. The primary outcome from this network meta-analysis was trial-defined major adverse cardiovascular event (MACE)—a composite of cardiovascular death, myocardial infarction (MI), and target lesion revascularization (TLR). PCI strategies were ranked (best to worst) using P scores. Our search identified 32 eligible randomized controlled trials and included a total of 22,684 patients. Compared with angiography-guided PCI, intravascular imaging-guided PCI was associated with reduced risk of MACE (relative risk [RR]: 0.72; 95% CI: 0.62-0.82), cardiovascular death (RR: 0.56; 95% CI: 0.42-0.75), MI (RR: 0.81; 95% CI: 0.66-0.99), stent thrombosis (RR: 0.48; 95% CI: 0.31-0.73), and TLR (RR: 0.75; 95% CI: 0.57-0.99). Similarly, when compared with angiography-guided PCI, functionally guided PCI was associated with reduced risk of MACE and MI. Intravascular imaging-guided PCI ranked first for the outcomes of MACE, cardiovascular death, stent thrombosis, and TLR. The results were consistent in the ACS and non-ACS cohorts. Angiography-guided PCI had consistently worse outcomes compared with intravascular imaging-guided and functionally guided PCI. Intravascular imaging-guided PCI was the best strategy to reduce the risk of cardiovascular events. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: The pressure-derived parameters fractional flow reserve (FFR) and the emerging instantaneous wave-free ratio (iFR) are the most widely applied invasive coronary physiology indices to guide revascularisation. However, approximately 15–20% of intermediate stenoses show discordant FFR and iFR, and therapeutical consensus is lacking. Aims: We sought to associate hyperaemic stenosis resistance index, coronary flow reserve (CFR) and coronary flow capacity (CFC) to FFR/iFR discordance. Methods: We assessed pressure and flow measurements of 647 intermediate lesions (593 patients) of two multi-centre international studies. Results: FFR and iFR were discordant in 15% of all lesions (97 out of 647). FFR+/iFR− lesions had similar hyperaemic average peak velocity (hAPV), CFR and CFC as FFR−/iFR− lesions, whereas FFR−/iFR+ lesions had similar hAPV, CFR and CFC as FFR+/iFR+ lesions (p > 0.05 for all). FFR+/iFR− lesions were associated with lower baseline stenosis resistance, but not hyperaemic stenosis resistance, compared with FFR−/iFR+ lesions (p < 0.001). Conclusions: Discordance with FFR+/iFR− is characterised by maximal flow values, CFR, and CFC patterns similar to FFR−/iFR− concordance that justifies conservative therapy. Discordance with FFR−/iFR+ on the other hand, is characterised by low flow values, CFR, and CFC patterns similar to iFR+/FFR+ concordance that may benefit from percutaneous coronary intervention. [ABSTRACT FROM AUTHOR]

Background and Aims Guidelines recommend revascularization of intermediate epicardial artery stenosis to be guided by evidence of ischaemia. Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are equally recommended. Individual 5-year results of two major randomized trials comparing FFR with iFR-guided revascularization suggested increased all-cause mortality following iFR-guided revascularization. The aim of this study was a study-level meta-analysis of the 5-year outcome data in iFR-SWEDEHEART (NCT02166736) and DEFINE-FLAIR (NCT02053038). Methods Composite of major adverse cardiovascular events (MACE) and its individual components [all-cause death, myocardial infarction (MI), and unplanned revascularisation] were analysed. Raw Kaplan–Meier estimates, numbers at risk, and number of events were extracted at 5-year follow-up and analysed using the ipdfc package (Stata version 18, StataCorp, College Station, TX, USA). Results In total, iFR and FFR-guided revascularization was performed in 2254 and 2257 patients, respectively. Revascularization was more often deferred in the iFR group [ n = 1128 (50.0%)] vs. the FFR group [ n = 1021 (45.2%); P =.001]. In the iFR-guided group, the number of deaths, MACE, unplanned revascularization, and MI was 188 (8.3%), 484 (21.5%), 235 (10.4%), and 123 (5.5%) vs. 143 (6.3%), 420 (18.6%), 241 (10.7%), and 123 (5.4%) in the FFR group. Hazard ratio [95% confidence interval (CI)] estimates for MACE were 1.18 [1.04; 1.34], all-cause mortality 1.34 [1.08; 1.67], unplanned revascularization 0.99 [0.83; 1.19], and MI 1.02 [0.80; 1.32]. Conclusions Five-year all-cause mortality and MACE rates were increased with revascularization guided by iFR compared to FFR. Rates of unplanned revascularization and MI were equal in the two groups. [ABSTRACT FROM AUTHOR]

Background and Objectives: Coronary angiography is the gold standard for diagnosing coronary artery disease (CAD). In the case of borderline changes, patients require further diagnosis through ischemia assessment via one of the recommended methods of invasive evaluation. This study aimed to assess whether clinical factors influence the risk of a positive result in invasive myocardial ischemia assessment and if these potential factors change with the patient's age and the consistency of ischemia assessment. Materials and Methods: Data were collected retrospectively on all consecutive patients hospitalized in the University Hospital in Krakow between 2020 and 2021, on whom physiological assessments of coronary circulation were performed. Patients were divided into two groups: patients aged 60 or younger and patients older than 60. Results: Despite the older patients having more risk factors for CAD, their physiological assessment results of borderline lesions were similar to those of the younger patients. Positive fractional flow reserve (FFR) assessments were obtained from almost 50% of vessels. In the younger patients, cigarette use and type 2 diabetes mellitus increased the risk of a positive FFR result by 3.5 and 2.5 times, respectively. In the older patients, male gender and peripheral vascular disease significantly increased the risk of a positive FFR by 2.5 and 2 times, respectively. Conclusions: Clinical characteristics of patients undergoing physiological assessment of borderline coronary stenosis varied significantly by age. Refining the definition of borderline lesions to include age, gender, and other factors may improve the identification of patients who would benefit from physiological assessment and coronary revascularization. [ABSTRACT FROM AUTHOR]

BACKGROUND: There is great degree of interobserver variability in the visual angiographic assessment of left main coronary disease (LMCD). Fractional flow reserve and intravascular ultrasound are often used in this setting. The use of instantaneous wave-free ratio (iFR) for evaluation of LMCD has not been well studied. The aim of this study is to evaluate the use of iFR in the assessment of angiographically intermediate LMCD. METHODS: This is an international multicenter retrospective observational study of patients who underwent both iFR and intravascular ultrasound evaluation for angiographically intermediate LMCD. An independent core laboratory performed blinded off-line analysis of all intravascular ultrasound data. A minimum lumen area of 6 mm2 was used as the cutoff for significant disease. RESULTS: One hundred twenty-five patients (mean age, 68.4±9.5 years, 84.8% male) were included in this analysis. Receiver operating curve analysis showed that an iFR of ≤0.89 identified minimum lumen area

Aim. To evaluate the accuracy of virtual stenting in predicting the physiological effect of percutaneous coronary intervention (PCI) for multilevel coronary artery disease (CAD).Material and methods. In order to define PCI strategy, 34 patients with multilevel CAD underwent assessment of instantaneous wave-free ratio (iFR) with mapping. Using the virtual stenting, predicted iFR (priFR) was assessed. After stent implantation, the factual iFR (fiFR) was re-assessed. A discrepancy between the priFR and fiFR by 0,03 was considered the threshold level of a significant difference and "poor agreement" criterion between measurements.Results. Mean iFR before PCI was 0,77±0,11; after PCI, this indicator increased significantly and amounted to 0,94±0,04 (p

Objective: The risk of vessel-oriented cardiac adverse events (VOCE) in patients with diabetes mellitus (DM) undergoing intracoronary physiology-guided coronary revascularization is poorly defined. The purpose of this work is to evaluate the risk of VOCE in patients with and without DM in whom percutaneous coronary intervention (PCI) was performed or deferred based on pressure-wire functional assessment. Methods: This is a retrospective analysis of a multicenter registry of patients evaluated with fractional flow reserve (FFR) and/or non-hyperaemic pressure ratio (NHPR). Primary endpoint was a composite of VOCE including cardiac death, vessel-related myocardial infarction (MI), and ischemia-driven target vessel revascularization (TVR). Results: A large cohort of 2828 patients with 3353 coronary lesions was analysed to assess the risk of VOCE at long-term follow-up (23 [14–36] months). Non-insulin-dependent-DM (NIDDM) was not associated with the primary endpoint in the overall cohort (adjusted Hazard Ratio [aHR] 1.18, 95% CI 0.87–1.59, P = 0.276) or in patients with coronary lesions treated with PCI (aHR = 1.30, 95% CI 0.78–2.16, P = 0.314). Conversely, insulin-dependent diabetes mellitus (IDDM) demonstrated an increased risk of VOCE in the overall cohort (aHR 1.76, 95% CI 1.07–2.91, P = 0.027), but not in coronary lesions undergoing PCI (aHR 1.26, 95% CI 0.50–3.16, P = 0.621). Importantly, in coronary lesions deferred after functional assessment IDDM (aHR 2.77, 95% CI 1.11–6.93, P = 0.029) but not NIDDM (aHR = 0.94, 95% CI 0.61–1.44, P = 0.776) was significantly associated with the risk of VOCE. IDDM caused a significant effect modification of FFR-based risk stratification (P for interaction < 0.001). Conclusion: Overall, DM was not associated with an increased risk of VOCE in patients undergoing physiology-guided coronary revascularization. However, IDDM represents a phenotype at high risk of VOCE. [ABSTRACT FROM AUTHOR]

The European Association of Percutaneous Cardiovascular Interventions (EAPCI) recently released a consensus statement on coronary physiology's role in managing percutaneous coronary interventions (PCI). Indeed, in recent years, significant advancements have been made in coronary imaging techniques, which have greatly improved our ability to assess stenosis features. Techniques like instantaneous wave-free ratio (iFR), fractional flow reserve (FFR), and longitudinal vessel analysis have evolved, providing insights into the hemodynamic significance of coronary lesions and guiding treatment decisions, particularly in PCI. This commentary aims to enlighten the critical issues of the EAPCI statement, briefly reviewing the main techniques for the study of coronary physiology and their applications. [ABSTRACT FROM AUTHOR]

There have been no studies comparing clinical outcomes of physiology-guided revascularization in patients with unprotected left main coronary disease (ULMD) between percutaneous coronary intervention (PCI) vs. coronary artery bypass grafting (CABG). The aim of this study was to assess the long-term clinical outcomes between PCI and CABG of patients with physiologically significant ULMD. From an international multicenter registry of ULMD patients interrogated with instantaneous wave-free ratio (iFR), we analyzed data from 151 patients (85 PCI vs. 66 CABG) who underwent revascularization according to the cutoff value of iFR ≤ 0.89. Propensity score matching was employed to adjust for baseline clinical characteristics. The primary endpoint was a composite of all-cause death, non-fatal myocardial infarction, and ischemia-driven target lesion revascularization. The secondary endpoints were the individual components of the primary endpoint. Mean age was 66.6 (± 9.2) years, 79.2% male. Mean SYNTAX score was 22.6 (± 8.4) and median iFR was 0.83 (IQR 0.74–0.87). After performing propensity score matching analysis, 48 patients treated with CABG were matched to those who underwent PCI. At a median follow-up period of 2.8 years, the primary endpoint occurred in 8.3% in PCI group and 20.8% in CABG group, respectively (HR 3.80; 95% CI 1.04–13.9; p = 0.043). There was no difference in each component of the primary event (p > 0.05 for all). Within the present study, iFR-guided PCI was associated with lower cardiovascular events rate in patients with ULMD and intermediate SYNTAX score, as compared to CABG. State-of-the-art PCI vs. CABG for ULMD. Study design and primary endpoint in patients with physiologically significant ULMD. MACE was defined as the composite of all-cause death, non-fatal myocardial infarction, and target lesion revascularization. The blue line denotes the PCI arm, and the red line denotes the CABG arm. PCI was associated with significantly lower risk of MACE than CABG. CABG: coronary artery bypass grafting; iFR: instantaneous wave-free ratio; MACE: major adverse cardiovascular events; PCI: percutaneous coronary intervention; ULMD: unprotected left main coronary artery disease. [ABSTRACT FROM AUTHOR]

Today, coronary artery disease (CAD) continues to be a prominent cause of death worldwide. A reliable assessment of coronary stenosis represents a prerequisite for the appropriate management of CAD. Nevertheless, there are still major challenges pertaining to some limitations of current imaging and functional diagnostic modalities. The present review summarizes the current data on invasive functional and intracoronary imaging assessment using optical coherence tomography (OCT), and intravascular ultrasound (IVUS). Amongst the functional parameters—on top of fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR)—we point to novel angiography-based measures such as quantitative flow ratio (QFR), vessel fractional flow reserve (vFFR), angiography-derived fractional flow reserve (FFRangio), and computed tomography-derived flow fractional reserve (FFR-CT), as well as hybrid approaches focusing on optical flow ratio (OFR), computational fluid dynamics and attempts to quantify the forces exaggerated by blood on the coronary plaque and vessel wall. [ABSTRACT FROM AUTHOR]

BackgroundPhysicians are not always comfortable deferring treatment of a stenosis in the left anterior descending (LAD) artery because of the perception that there is a high risk of major adverse cardiac events (MACE). The authors describe, using the DEFINE-FLAIR (Functional Lesion Assessment of Intermediate Stenosis to Guide Revascularisation) trial, MACE rates when LAD lesions are deferred, guided by physiological assessment using fractional flow reserve (FFR) or the instantaneous wave-free ratio (iFR).ObjectivesThe purpose of this study was to establish the safety of deferring treatment in the LAD using FFR or iFR within the DEFINE-FLAIR trial.MethodsMACE rates at 1 year were compared between groups (iFR and FFR) in patients whose physiological assessment led to LAD lesions being deferred. MACE was defined as a composite of cardiovascular death, myocardial infarction (MI), and unplanned revascularization at 1 year. Patients, and staff performing follow-up, were blinded to whether the decision was made with FFR or iFR. Outcomes were adjusted for age and sex.ResultsA total of 872 patients had lesions deferred in the LAD (421 guided by FFR, 451 guided by iFR). The event rate with iFR was significantly lower than with FFR (2.44% vs. 5.26%; adjusted HR: 0.46; 95% confidence interval [CI]: 0.22 to 0.95; p = 0.04). This was driven by significantly lower unplanned revascularization with iFR and numerically lower MI (unplanned revascularization: 2.22% iFR vs. 4.99% FFR; adjusted HR: 0.44; 95% CI: 0.21 to 0.93; p = 0.03; MI: 0.44% iFR vs. 2.14% FFR; adjusted HR: 0.23; 95% CI: 0.05 to 1.07; p = 0.06).ConclusionsiFR-guided deferral appears to be safe for patients with LAD lesions. Patients in whom iFR-guided deferral was performed had statistically significantly lower event rates than those with FFR-guided deferral.

Adequate personalized numerical simulation of hemodynamic indices in coronary arteries requires accurate identification of the key parameters. Elastic properties of coronary vessels produce a significant effect on the accuracy of simulations. Direct measurements of the elasticity of coronary vessels are not available in the general clinic. Pulse wave velocity (AoPWV) in the aorta correlates with aortic and coronary elasticity. In this work, we present a neural network approach for estimating AoPWV. Because of the limited number of clinical cases, we used a synthetic AoPWV database of virtual subjects to train the network. We use an additional set of AoPWV data collected from real patients to test the developed algorithm. The developed neural network predicts brachial–ankle AoPWV with a root-mean-square error (RMSE) of 1.3 m/s and a percentage error of 16 % . We demonstrate the relevance of a new technique by comparing invasively measured fractional flow reserve (FFR) with simulated values using the patient data with constant ( 7.5 m/s) and predicted AoPWV. We conclude that patient-specific identification of AoPWV via the developed neural network improves the estimation of FFR from 4.4 % to 3.8 % on average, with a maximum difference of 2.8 % in a particular case. Furthermore, we also numerically investigate the sensitivity of the most useful hemodynamic indices, including FFR, coronary flow reserve (CFR) and instantaneous wave-free ratio (iFR) to AoPWV using the patient-specific data. We observe a substantial variability of all considered indices for AoPWV below 10 m/s and weak variation of AoPWV above 15 m/s. We conclude that the hemodynamic significance of coronary stenosis is higher for the patients with AoPWV in the range from 10 to 15 m/s. The advantages of our approach are the use of a limited set of easily measured input parameters (age, stroke volume, heart rate, systolic, diastolic and mean arterial pressures) and the usage of a model-generated (synthetic) dataset to train and test machine learning methods for predicting hemodynamic indices. The application of our approach in clinical practice saves time, workforce and funds. [ABSTRACT FROM AUTHOR]

Discordance between fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) occurs in approximately 20 % of cases. However, no studies have reported the discordance in patients with severe aortic stenosis (AS). We aimed to evaluate the diagnostic discordance between FFR and iFR in patients with severe AS. We examined 140 consecutive patients with severe AS (164 intermediate coronary artery stenosis vessels). FFR and iFR were calculated in four quadrants based on threshold FFR and iFR values of ≤0.8 and ≤0.89, respectively (Group 1: iFR >0.89, FFR >0.80; Group 2: iFR ≤0.89, FFR >0.80; Group 3: iFR >0.89, FFR ≤0.80; and Group 4: iFR ≤0.89, FFR ≤0.80). Concordant groups were Groups 1 and 4, and discordant groups were Groups 2 and 3. Positive and negative discordant groups were Groups 3 and 2, respectively. The median (Q1, Q3) FFR and iFR were 0.84 (0.76, 0.88) and 0.85 (0.76, 0.91), respectively. Discordance was observed in 48 vessels (29.3 %). In the discordant group, negative discordance (Group 2: iFR ≤0.89 and FFR >0.80) was predominant (45 cases, 93.6 %). Multivariate analysis showed that the left anterior descending artery [odds ratio (OR), 3.88; 95 % confidence interval (CI): 1.54–9.79, p = 0.004] and peak velocity ≥5.0 m/s (OR, 3.21; 95%CI: 1.36–7.57, p = 0.008) were independently associated with negative discordance (FFR >0.8 and iFR ≤0.89). In patients with severe AS, discordance between FFR and iFR was predominantly negative and observed in 29.3 % of vessels. The left anterior descending artery and peak velocity ≥5.0 m/s were independently associated with negative discordance. [Display omitted] • The discordance rate between FFR and iFR was 29.3% in patients with aortic stenosis. • Negative discordance (FFR >0.8 and iFR ≤0.89) was dominant in discordant cases. • Left anterior descending artery lesions were associated with negative discordance. • Peak velocity ≥5.0 m/s was independently associated with negative discordance. [ABSTRACT FROM AUTHOR]

Coronary physiologic assessment has become a standard of care for patients with coronary atherosclerotic disease. While most attention has focused on pre-interventional physiologic assessment to aid in revascularization decision-making, post-interventional physiologic assessment has not been as widely used, despite evidence supporting its role in assessment and optimization of the revascularization procedure. A thorough understanding of such evidence and ongoing studies would be crucial to incorporate post-interventional physiologic assessment into daily practice. Thus, this review provides a comprehensive overview of current evidence regarding the evolving role of physiologic assessment as a functional optimization tool for the entire revascularization process. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction and objectives: The safety of physiology-based revascularization in patients with diabetes mellitus has been scarcely investigated. Our objective was to determine the safety of deferring revascularization based on the fractional flow reserve (FFR) or the instantaneous wave-free ratio (iFR) in diabetic patients. Methods: Single-center, retrospective analysis of patients with intermediate coronary stenoses in whom revascularization was deferred based on FFR > 0.80 or iFR > 0.89 values. The long-term rate of major adverse cardiovascular events, a composite of all-cause mortality, myocardial infarction, and target vessel revascularization (TVR), was assessed in diabetic and non-diabetic patients at the follow-up. The rate of TVR based on the type of physiological index used to defer the lesion was also evaluated. Results: We evaluated 164 diabetic (214 vessels) and 280 non-diabetic patients (379 vessels). No significant differences in the rate of major adverse cardiovascular events was seen between diabetic and non-diabetic patients (20.1% vs 13.2%; P = .245) at a median follow-up of 43 months. All-cause mortality and cardiac death were not statistically different between both groups in the adjusted analysis (P > .05). A trend towards a higher rate of myocardial infarction was seen in diabetic patients (6.7% vs 2.9%; P = .063). However, the rate of target vessel myocardial infarction was similar in both groups (P = .874). Overall, TVR was similar in diabetics and non-diabetics (4.7% vs 4.2%; P = .814); however, when analyzed based on the physiological index, numerically, diabetics had a higher rate of TVR when the FFR was used in the decision-making process compared to when the iFR was used (6.4% vs 0.0%; P = .064). Conclusions: Deferring the revascularization of intermediate stenoses in patients with DM based on the FFR or the iFR is safe regarding the risk of TVR or target vessel myocardial infarction, with a rate of events at the long-term follow-up similar to that seen in non-diabetic patients.

• Dual-center clinical data of the myocardial ischemia and other haemodynamic indicators of 186 patients was collected in this study. The amount of data is sufficient. • A simplified coronary stenosis-microcirculation resistance single-branch model based on deep learning and lumped parameter model technology was established to quickly calculate instantaneous wave-free ratio (iFR CT). Only 8 s are needed to conduct the calculation for 205 diseased vessels of 186 patients. • Compensation mechanism of coronary microcirculation resistance was considered to establish a high-fidelity model in the resting state in line with human physiological mechanism, thus ensuring accuracy of iFR CT calculation while simplifying the model. Instantaneous wave-free ratio (iFR) is a new invasive indicator of myocardial ischaemia, and its diagnostic performance is as good as the "gold standard" of myocardial ischaemia diagnosis: fractional flow reserve (FFR). iFR can be approximated by iFR CT , which is calculated based on noninvasive coronary CT angiography (CTA) images and computational fluid dynamics (CFD). However, the existing methods for calculating iFR CT fail to accurately simulate the resting state of the coronary artery, resulting in low computational accuracy. Furthermore, the use of CFD technology limits its computational efficiency, making it difficult to meet clinical application needs. The role of coronary microcirculatory resistance compensation suggests that microcirculatory resistance can be adaptively reduced to compensate for increases in coronary stenotic resistance, thereby maintaining stable myocardial perfusion in the resting state. It is therefore necessary to consider this compensation mechanism to establish a high-fidelity microcirculation resistance model in the resting state in line with human physiology, and so to achieve accurate calculation of iFR CT. In this study we successfully collected clinical data, such as FFR, in 205 stenotic vessels from 186 patients with coronary heart disease. A neural network model was established to predict coronary artery stenosis resistance. Based on the compensation mechanism of coronary microcirculation resistance, an iterative solution algorithm for microcirculation resistance in the resting state was developed. Combining the two methods, a simplified single-branch model combining coronary stenosis and microcirculation resistance was established, and the noninvasive and rapid numerical calculation of iFR CT was performed. The results showed that the mean squared error (MSE) between the pressure drop predicted by the neural network value for the coronary artery stenosis model and the ground truth in the test set was 0.053 %, and correlation analysis proved that there was a good correlation between them (r = 0.99, p < 0.001). With reference to clinical diagnosis of myocardial ischaemia (using FFR as the gold standard), the diagnostic accuracy of the iFR CT calculation model for the 205 cases was 88.29 % (r = 0.71, p < 0.001), and the total calculation time was < 8 s. The results of this study demonstrate the utility of a simplified single-branch model in an iFR CT calculation method based on haemodynamics and deep learning, which is important for noninvasive and rapid diagnosis of myocardial ischaemia. [ABSTRACT FROM AUTHOR]

Background and Objectives: Coronary angiography is the gold standard for diagnosing coronary artery disease (CAD). In the case of borderline changes, patients require further diagnosis through ischemia assessment via one of the recommended methods of invasive evaluation. This study aimed to assess whether clinical factors influence the risk of a positive result in invasive myocardial ischemia assessment and if these potential factors change with the patient’s age and the consistency of ischemia assessment. Materials and Methods: Data were collected retrospectively on all consecutive patients hospitalized in the University Hospital in Krakow between 2020 and 2021, on whom physiological assessments of coronary circulation were performed. Patients were divided into two groups: patients aged 60 or younger and patients older than 60. Results: Despite the older patients having more risk factors for CAD, their physiological assessment results of borderline lesions were similar to those of the younger patients. Positive fractional flow reserve (FFR) assessments were obtained from almost 50% of vessels. In the younger patients, cigarette use and type 2 diabetes mellitus increased the risk of a positive FFR result by 3.5 and 2.5 times, respectively. In the older patients, male gender and peripheral vascular disease significantly increased the risk of a positive FFR by 2.5 and 2 times, respectively. Conclusions: Clinical characteristics of patients undergoing physiological assessment of borderline coronary stenosis varied significantly by age. Refining the definition of borderline lesions to include age, gender, and other factors may improve the identification of patients who would benefit from physiological assessment and coronary revascularization.

Aim. To conduct a systematic review and meta-analysis to compare clinical outcomes in patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI) using conventional coronary angiography (CAG) or fractional flow reserve (FFR)-guided PCI. In addition, FFR-guided PCI and PCI guided with instantaneous wave-free ratio (iFR) were compared.Material and methods. PubMed, Google Scholar databases were searched for studies comparing clinical outcomes in patients with CAD undergoing CAG-guided or FFR/iFR-guided PCI. Dichotomous data analysis was presented as odds ratio (OR) with 95% confidence interval (CI). Adjusted hazard ratio (HR) values from studies with similar evaluation criteria were pooled for meta-analysis.Results. Six randomized controlled trials (RCTs) from 184 publications were selected for this systematic review and meta-analysis. A total of 2193 patients (mean age, 64,2 years, mean follow-up, 28,0 months) were included. Analysis of RCTs showed that CAG-guided and FFR-guided PCI did not have a significant difference in the incidence of major adverse cardiovascular events (MACE) (OR: 0,78; 95% CI: 0,61-1,00; p=0,05; I2=0%), all-cause death (OR: 0,86; 95% CI: 0,51-1,44; p=0,57; I2=0%) or emergency revascularization (OR: 0,69, 95% CI: 0,46-1,04, p=0,08, I2=0%). However, FFR-guided PCI was associated with a reduced risk of subsequent MI compared with CAG-guided PCI (OR: 0,70; 95% CI: 0,50-0,99; p=0,04; I2=0%). In addition to the results of previous RCTs, we conducted a metaanalysis of 3 observational studies. In total, the CAG-guided and FFR-guided PCI groups included 165012 and 11450 patients, respectively. A meta-analysis showed that FFR-guided PCI was associated with a reduced risk of all-cause mortality (HR: 0,74; 95% CI: 0,63-0,87; P=0,0003) and MI (HR: 0,75; 95% CI: 0,61-0,94; p=0,01). In addition, there was no significant difference between iFRand FFR-guided PCI in terms of MACE (OR: 0,97; 95% CI: 0,76-1,23; p=0,81), all-cause mortality (OR: 0,66; 95% CI: 0,40-1,10; p=0,11), MI (OR: 0,83; 95% CI: 0,56-1,24; p=0,37) or emergency repeated revascularization (OR: 1,16; 95% CI: 0,85-1,58; p=0,34).Conclusion. FFR-guided PCI is associated with a reduced risk of all-cause mortality and subsequent MI compared with CAG-guided PCI. At the same time, the iFR-guided PCI is not inferior to the FFR-guided method in terms of MACE rate.

Background Although physiology‐based assessment of coronary artery stenosis using instantaneous wave‐free ratio (iFR) and fractional flow reserve (FFR) are established methods of guiding coronary revascularization, its clinical outcome in long‐term deferral needs further evaluation, especially with acute coronary syndrome as a clinical presentation. The aim was to evaluate the long‐term clinical outcome of deferral of revascularization based on iFR or FFR. Methods and Results This is a substudy of the iFR‐SWEDEHEART (Instantaneous Wave‐Free Ratio Versus Fractional Flow Reserve in Patients With Stable Angina Pectoris or Acute Coronary Syndrome) randomized clinical trial, where patients deferred from revascularization from each study arm were selected. Nine hundred eight patients deferred from coronary revascularization with iFR (n=473) and FFR (n=435) were followed for 5 years. The national quality registry, SWEDEHEART (Swedish Web‐System for Enhancement and Development of Evidence‐Based Care in Heart Disease Evaluated According to Recommended Therapies), was used for patient data collection and clinical follow‐up. The end point was major adverse cardiac events and their individual components all‐cause death, cardiovascular death, noncardiovascular death, nonfatal myocardial infarction, and unplanned revascularization. No significant difference was found in major adverse cardiac events (iFR 18.6% versus FFR 16.8%; adjusted hazard ratio, 1.08 [95% CI, 0.79–1.48]; P=0.63) or their individual components. Conclusions No differences in clinical outcomes after 5‐year follow‐up were noted when comparing iFR versus FFR as methods for deferral of coronary revascularization in patients presenting with stable angina pectoris and acute coronary syndrome. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02166736.

[Display omitted] [ABSTRACT FROM AUTHOR]

Coronary artery disease is the leading cause of mortality worldwide, accounting for 12.8% of all deaths. Although the clinical benefits of treating stenosis with percutaneous coronary intervention (PCI) have been extensively demonstrated, residual myocardial ischemia remains in about 30–50% of patients even after a formally successful PCI. We apply previously developed and validated 1D model of haemodynamics, which distributes terminal hydraulic resistance based on the diameters of the parent vessels and Murray's law by a recursive algorithm. In our new model the terminal resistance is decreased according to a transmural perfusion ratio increase. In contrast to our previous work we calculate the transmural perfusion ratio for personally defined zones. Thus, peripheral hydraulic resistance of myocardial perfusion is personalized based on patient data, whichwere extracted from computed tomography perfusion images. The model serves as a computational tool for simulating pre- to post-PCI changes in coronary haemodynamics of four patients. We simulate fractional flow reserve (FFR), coronary flow reserve (CFR), instantaneous wave-free ratio (iFR), average flow in selected arteries in hyperemic and rest conditions before PCI and after PCI immediately after the surgery (in a short-term) and in a long-term (several months) perspectives. We conclude that high FFR and iFR values in short-term and long-term perspectives are not necessary correlate with CFR improvement and long-term blood flow recovery in coronary arteries. [ABSTRACT FROM AUTHOR]

The physiological assessment of coronary lesions is influenced by the pattern and distribution of coronary artery disease (CAD), including focal lesions, serial lesions, diffuse disease, and mixed patterns. These various patterns of CAD impact the accuracy of pressure wire and angiography-derived physiology indexes, and diffuse disease in particular is an important determinant of the anticipated outcome of percutaneous coronary intervention. Therefore, identification of the physiological pattern of disease provides relevant information for the management of CAD and percutaneous coronary intervention procedural planning. At present, the classification of physiological patterns and its implications for the tailored management of a patient with CAD are poorly defined. This state-of-the-art review provides an overview of the available evidence on functional patterns of CAD with a special focus on their diagnostic and therapeutic implications. It also aims to provide clear definitions of physiological patterns of CAD based on the available evidence and expert opinion. A practical algorithm is provided to optimize the use of pressure wire and angiography-derived indexes of coronary physiology in the settings of focal, serial, and diffuse lesions, with the addition of intracoronary imaging in selected cases. [Display omitted] • The assessment of functional patterns of CAD provides crucial information on the revascularization decision strategy and procedural planning. • PCI in diffuse disease often yields suboptimal results. In this scenario, physiological longitudinal assessment may identify residual gradients amenable to further intervention. • Longitudinal functional assessment provides a third dimension to CAD characterization, in addition to the angiographic and functional evaluation of lesion significance. [ABSTRACT FROM AUTHOR]

Background: Intravascular ultrasound (IVUS) guides deferral decision-making regarding the left main coronary artery (LMCA) and improves outcomes. Further studies regarding coronary physiology to guide revascularization in the LMCA are needed. Our aim was to evaluate the outcome of LMCA deferral using IVUS or coronary physiology via instantaneous wave-free ratio (iFR) or fractional flow reserve (FFR)., Methods: Between January 2014 and February 2022, patients undergoing evaluation with either IVUS or coronary physiology in the LMCA were included from the SWEDEHEART registry. Exclusion criteria were a minimum luminal area < 6 mm 2 , iFR ≤ 0.89, FFR ≤ 0.80, ad hoc percutaneous coronary intervention of lesions in the LMCA, proximal left anterior descending artery, and proximal circumflex artery, planned elective revascularization, and planned valvular surgery. The primary outcome was major adverse cardiac events (MACE), defined as a composite of all-cause death, myocardial infarction, and unplanned revascularization. Kaplan-Meier event rates and multivariable Poisson regression were used for the statistical analyses., Results: Deferral of revascularization in the LMCA was performed in 1552 patients, 33.6 % with IVUS and 66.4 % with coronary physiology (iFR 11.3 % vs. FFR 55.0 %). The median follow-up time was 2.7 years. No significant difference was seen in MACE (IVUS 40.2 % vs. coronary physiology 35.5 %; adjusted RR: 1.18; 95 %CI: 0.97-1.44; p = 0.09). The results were consistent across all investigated subgroups. The rate of all-cause death was higher in the IVUS group (adjusted RR: 1.38; 95 %CI: 1.03-1.83; p = 0.03)., Conclusions: Deferral of coronary revascularization in LMCA lesions using IVUS or coronary physiology did not differ in our combined endpoint. We observed a higher risk of all-cause death using IVUS., Competing Interests: Declaration of competing interest Matthias Götberg received minor consulting fees from Abbott, Boston, Medtronic, and Philips. Karolina Berntorp, Moman A Mohammad, Sasha Koul, Troels Yndigegn, Sofia Bergman, Sammy Zwackman, Rikard Linder, Sebastian Völz, Ole Fröbert, and David Erlinge have no disclosures to report., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background and hypothesisThe field of coronary artery physiology is developing rapidly and changing the practice of interventional cardiology. A new functional evaluation technique using the instantaneous wave-free ratio (iFR) has become an alternative to fractional flow reserve. Future research studies need to determine whether physiological indicators play a role in evaluating myocardial perfusion in the catheter room.Materials and methodsThirty-eight patients scheduled for coronary angiography and iFR evaluation underwent a real-time myocardial contrast echocardiography (RT-MCE) examination at rest. The myocardial perfusion parameters (A, β, and A × β) on the myocardial perfusion curve were quantitatively analyzed using Q-Lab software. Coronary angiography and iFR assessment were completed within 1 week after the RT-MCE examination in all patients. Correlation analysis was used to identify iFR- and MCE-related indicators. The sensitivity and specificity of iFR in the quantitative detection of coronary microcirculation were obtained.ResultsThe correlation coefficients between iFR and A, β, and A × β were 0.81, 0.66, and 0.82, respectively. The cut-off value for iFR was 0.85 for microvascular ischemia detection, while the sensitivity and specificity for the diagnosis of myocardial perfusion were 90.7 and 89.9%, respectively. The receiver operating characteristic (ROC) curve area for iFR was 0.946 in the segments related to myocardial blood flow.ConclusionThe iFR is an effective tool for detecting myocardial microcirculation perfusion, with satisfactory diagnostic performance and a demonstrated role in physiological indices used for the perfusion assessment.

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. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction and objectives: patients with long, sequential and diffuse coronary lesions who undergo a percutaneous coronary intervention remain at a high risk of suffering cardiovascular events despite the improved safety and efficacy of the new drug-eluting stents. The objective of this study was to analyze the utility of SyncVision/iFR-guided revascularization (SyncVision version 4.1.0.5, Philips Volcano, Belgium) in this type of lesions. Methods: Randomized, multicenter, controlled, and open-label trial designed to compare SyncVision/iFR-guided and angiography-guided revascularizations in patients with long, sequential or diffuse significant angiographic coronary stenosis (ClinicalTrials.gov identifier: NCT04283734). A total of 100 patients will be randomized (1:1, no stratification). The primary endpoint is the average length of the stent implanted. The secondary endpoint is a composite of cardiac death, myocardial infarction, definitive or probable stent thrombosis, new target lesion revascularization or new target lesion failure; and the presence of residual ischemia as seen on single-photon emission computed tomography at the 6-month follow-up. Patients will be followed for 12 months after the procedure. Results: The trial is currently in the recruitment phase, and it has already recruited the first 7 patients. We expect to complete the recruitment phase by February 2021 and the follow-up by February 2022. Conclusions: The iLARDI study is the first randomized trial to assess the potential utility of SyncVision-guided revascularization in long, sequential and diffuse coronary lesions.

Plaques associated with abnormally low physiological flow reserve indices are appropriate for percutaneous coronary intervention (PCI). However, recent trials demonstrate that PCI of ischemia-producing lesions does not reduce major adverse cardiac events (MACE). Low endothelial shear stress (ESS) or high ESS gradient (ESSG) are associated with MACE wherever they occur along the plaque. This study aims to determine the presence of high-risk ESS metrics in obstructive coronary plaques with high-risk (<0.80) vs. borderline-risk (0.80–0.89) vs. normal Instantaneous Wave-free Ratio (iFR) (>0.89). We included 50 coronary arteries (50 patients) with variable iFR values who underwent coronary angiography and optical coherence tomography (OCT), followed by 3D reconstruction and computational fluid dynamics calculations of ESS/ESSG. The cohort was divided into 3 groups: iFR < 0.80, iFR 0.80–0.89, and iFR > 0.89. Spatial distribution of ESS metrics was reported along the course of each plaque, and high-risk ESS metrics and their location were compared among the 3 iFR subgroups. High-risk ESS features (Minimal ESS, Maximum ESSG) were similarly distributed along the course of the atherosclerotic plaque in the three iFR subgroups, both in absolute value and in location: Min ESS: 0.5 ± 0.3 vs. 0.4 ± 0.2 vs. 0.4 ± 0.2 Pa respectively (p = 0.60); Max ESSG any direction: 13.7 ± 9.4 vs. 10.4 ± 10.6 vs. 10.0 ± 7.8 Pa/mm respectively (p = 0.30). ESS metrics were spatially located up to ≥18 mm from the plaque minimal luminal area (MLA) in both directions. High-risk ESS metrics are similarly observed in plaques with normal or abnormal iFR, both in absolute value and spatial location in reference to the MLA. Utilizing iFR to identify plaques likely to cause MACE would miss the majority of plaques mechanistically at high-risk to destabilize and cause future adverse cardiac events. [Display omitted] • The high-risk ESS metrics are equally distributed along the course of the coronary atherosclerotic plaques. • The distribution of the ESS metrics is not related to the degree of anatomical or physiological indices of ischemia. • A revascularization decision based on iFR value only can miss a high-risk plaque located at a distance from the MLA site. [ABSTRACT FROM AUTHOR]

Patients with multivessel coronary artery disease require an individual approach when choosing tactics for myocardial revascularization. In some cases, additional methods for assessing the stenosis significance should be used, such as measuring the fractional or instantaneous wave-free ratio, in order to decide on the most optimal and safe management of a patient. The article presents a case report of a change in the functional significance of stenosis of the left anterior descending artery (donor artery) after endovascular treatment in the right coronary and circumflex artery systems in a patient with three-vessel coronary disease and diabetes.

Coronary physiological assessment using fractional flow reserve or nonhyperemic pressure ratios has become a standard of care for patients with coronary atherosclerotic disease. However, most evidence has focused on the pre-interventional use of physiological assessment to aid revascularization decision-making, whereas post-interventional physiological assessment has not been well established. Although evidence for supporting the role of post-interventional physiological assessment to optimize immediate revascularization results and long-term prognosis has been reported, a more thorough understanding of these data is crucial in incorporating post-interventional physiological assessment into daily practice. Recent scientific efforts have also focused on the potential role of pre-interventional fractional flow reserve or nonhyperemic pressure ratio pullback tracings to characterize patterns of coronary atherosclerotic disease to better predict post-interventional physiological outcomes, and thereby identify the appropriate revascularization target. Pre-interventional pullback tracings with dedicated post-processing methods can provide characterization of focal versus diffuse disease or major gradient versus minor gradient stenosis, which would result in different post-interventional physiological results. This review provides a comprehensive look at the current evidence regarding the evolving role of physiological assessment as a functional optimization tool for the entire process of revascularization, and not merely as a pre-interventional tool for revascularization decision-making.

Background: This study aimed to assess the impact of the measurement of the degree of target coronary artery stenosis using the instantaneous wave-free ratio (iFR) on patency of attached grafts. Materials and Methods: A total of 86 grafts were assessed by computed tomography angiography (CTA) after coronary artery bypass grafting (CABG) in 24 patients with multivessel coronary artery disease (CAD). The iFR was evaluated for all target coronary arteries. The coronary artery stenoses were divided into three groups based on the iFR value: iFR < 0.86 (group 1); iFR 0.86–0.90 (group 2); and iFR > 0.90 (group 3). Results: CTA was performed at 192 ± 44 days (range: 80–318 days). The correlation coefficient (r) between iFR and failed grafts was 0.332 (p = 0.035). Graft failure was detected in three grafts (8.1%) for group 1, in two grafts (8.3 %) for group 2, and in four grafts (16%, all arterial grafts) for group 3. Statistically significant differences were found between groups 1 and 3 (p = 0.041) and between groups 2 and 3 (p = 0.044). No significant differences were found between groups 1 and 2 (p = 0.228). Conclusions: The degree of coronary artery stenosis measured by iFR is a risk factor for attached graft failure. In a coronary artery where the iFR was haemodynamically non-significant, a higher rate of graft failure was detected.

Today, coronary artery disease (CAD) continues to be a prominent cause of death worldwide. A reliable assessment of coronary stenosis represents a prerequisite for the appropriate management of CAD. Nevertheless, there are still major challenges pertaining to some limitations of current imaging and functional diagnostic modalities. The present review summarizes the current data on invasive functional and intracoronary imaging assessment using optical coherence tomography (OCT), and intravascular ultrasound (IVUS). Amongst the functional parameters—on top of fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR)—we point to novel angiography-based measures such as quantitative flow ratio (QFR), vessel fractional flow reserve (vFFR), angiography-derived fractional flow reserve (FFRangio), and computed tomography-derived flow fractional reserve (FFR-CT), as well as hybrid approaches focusing on optical flow ratio (OFR), computational fluid dynamics and attempts to quantify the forces exaggerated by blood on the coronary plaque and vessel wall.

Whether a coronary lesion with discordant fractional flow reserve (FFR) and non-hyperemic pressure ratios (NHPRs) causes myocardial ischemia remains unclear. This study investigates the prevalence of myocardial ischemia as assessed by myocardial perfusion scintigraphy (MPS) in coronary lesions with discordant FFR and instantaneous wave-free ratio (iFR), and, additionally, other NHPRs: resting full-cycle ratio (RFR), diastolic pressure ratio (dPR), and resting Pd/Pa. A total of 484 coronary arteries in 295 patients with stable coronary artery disease that underwent MPS and invasive physiological pressure measurements were categorized into four groups (FFR+/NHPR+, FFR+/NHPR-, FFR-/NHPR+, and FFR-/NHPR-) using the respective cut-off values of FFR ≤ 0.80, iFR ≤ 0.89, RFR ≤ 0.89, dPR < 0.89, and Pd/Pa ≤ 0.92. The proportions of MPS-derived myocardial ischemia in a relevant myocardial territory were compared between the four groups. In total, 175 (36%), 61(13%), 35(7%) and 213(44%) vessels were classified into FFR+/iFR+, FFR+/iFR-, FFR-/iFR+ and FFR-/iFR- groups, respectively. The FFR+/iFR+ group had the highest proportion of MPS-derived ischemia (70%), followed by the FFR+/iFR- group (38%), the FFR-/iFR+ group (23%), and the FFR-/iFR- group (10%) (P < 0.001). Similar proportions of MPS-derived ischemia were found when RFR. (70%, 34%, 24%, and 10%, P < 0.001), dPR (70%, 38%, 26%, and 10%, P < 0.001), and Pd/Pa (70%, 31%, 22%, and 10%, P < 0.001) were used in place of iFR. The prevalence of MPS-derived myocardial ischemia in coronary lesions with discordance between FFR and NHPRs is lower than those with concordantly positive FFR and NHPRs, but higher than those with concordantly negative FFR and NHPRs. • FFR and NHPR individually agree well with ischemia on myocardial perfusion imaging. • Highest prevalence of ischemia was found when FFR and NHPR were concordantly positive. • Prevalence of ischemia was the lowest when FFR and NHPR were concordantly negative. • Discordant FFR and NHPR were associated with intermediate prevalence of ischemia. • Similar trends were seen in the prevalence of myocardial ischemia whether MVD or SVD. [ABSTRACT FROM AUTHOR]

The diagnostic accuracy and clinical benefits of instantaneous wave-free ratio (iFR) compared to fractional flow reserve (FFR) have been well-established in the literature. Despite the advantages of non-hyperemic pressure indices, approximately 20% of iFR and FFR measurements are discordant. Efforts have been made to establish the mechanisms as well as identify causative factors that lead to such a discordance. Recent studies have identified many factors of discordance including sex differences, age differences, bradycardia, coronary artery stenosis location, elevated left ventricular end-diastolic pressure, and diastolic dysfunction. Additionally, discordance secondary to coronary artery microcirculation dysfunction, as seen in diabetics and patients on hemodialysis, has sparked interest amongst experts. As more interventional cardiologists are utilizing iFR independent of FFR to guide percutaneous coronary intervention an emphasis has been placed on identifying factors leading to discordance. The aim of this review is to outline recent studies that have identified factors of FFR and iFR discordance. [ABSTRACT FROM AUTHOR]