Fractional flow reserve for the assessment of nonculprit coronary artery stenoses in patients with acute myocardial infarction

Prognostic impact of quantitative flow ratio (QFR)-consistent complete revascularization in patients with myocardial infarction and multivessel coronary artery disease

BACKGROUND

Complete revascularization is associated with improved outcomes in patients with myocardial infarction and multivessel coronary artery disease. Quantitative flow ratio (QFR) represents an emerging angiography-based tool for functional lesion assessment. The present study investigated the prognostic impact of QFR-consistent complete revascularization in patients with myocardial infarction and multivessel disease.

METHODS

A total of 792 patients with myocardial infarction and multivessel disease were enrolled in the analysis. Post-hoc QFR analyses of 1320 non-culprit vessels were performed by investigators blinded to clinical outcomes. The primary endpoint was a composite of all-cause death, non-culprit vessel related non-fatal myocardial infarction, and ischemia-driven revascularization at two years after index myocardial infarction. Patients were stratified into a QFR-consistent PCI group (n=646) and a QFR-inconsistent PCI group (n=146), based on whether the intervention was congruent with the QFR-determined functional significance of the non-culprit lesions.

RESULTS

The primary endpoint occurred in a total of 22 patients (3.4%) in the QFR-consistent PCI group and in 27 patients (18.5%) in the QFR-inconsistent group (HR 0.17, 95%CI 0.10-0.30, p<0.001).The difference in the primary endpoint was driven by reduced rates of non-fatal myocardial infarction (2.0% vs. 15.1%; HR 0.13, 95%CI 0.06-0.25; p<0.001) and ischemia-driven revascularization (1.2% vs. 5.5%; HR 0.21, 95%CI 0.08-0.57; p=0.001) in the QFR-consistent PCI group.

CONCLUSIONS

Among patients with myocardial infarction and multivessel disease, a QFR-consistent complete revascularization was associated with a reduced risk of all-cause mortality, non-fatal myocardial infarction, and ischemia-driven revascularization. These findings underline the value of angiography-based functional lesion assessment for personalized revascularization strategies.

Percutaneous Coronary Revascularization Strategies After Myocardial Infarction: A Systematic Review and Network Meta-Analysis

BACKGROUND

Complete revascularization with percutaneous coronary intervention improves outcomes compared with culprit revascularization following myocardial infarction (MI) with multivessel coronary artery disease. An all-cause mortality reduction has never been demonstrated. Debate also remains regarding the optimal timing of complete revascularization (immediate or staged), and method of evaluation of nonculprit lesions (physiology or angiography).

OBJECTIVES

This study aims to perform an updated systematic review with frequentist and Bayesian network meta-analyses including the totality of randomized data investigating revascularization strategies in patients presenting with MI and multivessel coronary artery disease.

METHODS

The primary comparison tested complete vs culprit revascularization. Timing and methods of achieving complete revascularization were assessed. The prespecified primary outcome was all-cause mortality. Outcomes were expressed as relative risk (RR) (95% CI).

RESULTS

Twenty-four eligible trials randomized 16,371 patients (weighted mean follow-up: 26.4 months). Compared with culprit revascularization, complete revascularization reduced all-cause mortality in patients with any MI (RR: 0.85; 95% CI: 0.74-0.99; P = 0.04). Cardiovascular mortality, MI, major adverse cardiac events and repeat revascularization were also significantly reduced. In patients presenting with ST-segment elevation myocardial infarction, the point estimate for all-cause mortality with complete revascularization was RR: 0.91 (95% CI: 0.78-1.05; P = 0.18). Rates of stent thrombosis, major bleeding, and acute kidney injury were similar. Immediate complete revascularization ranked higher than staged complete revascularization for all endpoints.

CONCLUSIONS

Complete revascularization following MI reduces all-cause mortality, cardiovascular mortality, MI, major adverse cardiac events, and repeat revascularization. There may be benefits to immediate complete revascularization, but additional head-to-head trials are needed.

FFR-Guided Complete or Culprit-Only PCI in Patients with Myocardial Infarction

BACKGROUND

The benefit of fractional flow reserve (FFR)-guided complete revascularization in patients with ST-segment elevation myocardial infarction (STEMI) and multivessel coronary artery disease remains unclear.

METHODS

In this multinational, registry-based, randomized trial, we assigned patients with STEMI or very-high-risk non-STEMI (NSTEMI) and multivessel disease who were undergoing primary percutaneous coronary intervention (PCI) of the culprit lesion to receive either FFR-guided complete revascularization of nonculprit lesions or no further revascularization. The primary outcome was a composite of death from any cause, myocardial infarction, or unplanned revascularization. The two key secondary outcomes were a composite of death from any cause or myocardial infarction and unplanned revascularization.

RESULTS

A total of 1542 patients underwent randomization, with 764 assigned to receive FFR-guided complete revascularization and 778 assigned to receive culprit-lesion-only PCI. At a median follow-up of 4.8 years (interquartile range, 4.3 to 5.2), a primary-outcome event had occurred in 145 patients (19.0%) in the complete-revascularization group and in 159 patients (20.4%) in the culprit-lesion-only group (hazard ratio, 0.93; 95% confidence interval [CI], 0.74 to 1.17; P = 0.53). With respect to the secondary outcomes, no apparent between-group differences were observed in the composite of death from any cause or myocardial infarction (hazard ratio, 1.12; 95% CI, 0.87 to 1.44) or unplanned revascularization (hazard ratio, 0.76; 95% CI, 0.56 to 1.04). There were no apparent between-group differences in safety outcomes.

CONCLUSIONS

Among patients with STEMI or very-high-risk NSTEMI and multivessel coronary artery disease, FFR-guided complete revascularization was not shown to result in a lower risk of a composite of death from any cause, myocardial infarction, or unplanned revascularization than culprit-lesion-only PCI at 4.8 years. (Funded by the Swedish Research Council and others; FULL REVASC ClinicalTrials.gov number, NCT02862119.).

FFRct use for acute chest pain triage in the emergency department: a cost-effectiveness analysis

AIMS

To model and assess the cost-effectiveness of CT-based fractional flow reserve (FFRct) for a population of low to intermediate risk patients for coronary artery disease (CAD) presenting to the emergency department (ED) with acute chest pain.

METHODS AND RESULTS

Using a decision tree model with a 1 year time horizon and from a health care perspective, two diagnostic pathways using FFRct are compared to current clinical routine combining coronary computed tomography angiography (CCTA) with an exercise test. Model data are drawn from the literature and nationally reported data. Outcomes are assessed as the number of avoided invasive coronary angiographies (ICAs) showing no obstructive CAD and quality of life (QoL) in a theoretical cohort of 1000 patients. Sensitivity analyses are performed to test the robustness of the results. Determining FFRct when CCTA is inconclusive is a cost-effective and dominant strategy with a potential saving of 198€/patient, 154 avoided unnecessary ICA showing no obstructive CAD (uICA)/1000 patients and an average improvement in QoL of 0.008 QALY/patient. With an additional 574€/patient, 8 avoided uICA/1000 patients and an improvement in QoL of 0.001 QALY/patient, a strategy where FFRct is always performed is cost-effective only when considering high cost-effectiveness thresholds.

CONCLUSIONS

For patients presenting to the ED with acute chest pain and a low to intermediate pre-test probability of CAD, a diagnostic strategy where FFRct is determined after an inconclusive CCTA is cost-effective. Clinical trials investigating both sensitivity and specificity of FFRct, as well as QoL associated with the use of this technology in this setting are warranted.

Reliability of Fractional Flow Reserve in Non-Infarct-Related Arteries in ST-Segment Elevation Myocardial Infarction Patients Undergoing a Pharmaco-Invasive Approach

Objectives We investigated the reproducibility of fractional flow reserve (FFR) of significant stenoses (≥70% narrowing) in the non-infarct related artery (NIRA) during the pharmaco-invasive percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) within 24 hours of thrombolysis and at a follow up of 2-3 weeks. Background STEMI with multivessel disease has worse outcomes. The benefits of FFR-directed PCI of NIRA at the time of primary PCI are yet controversial. Assessing the hemodynamic severity of the NIRA may help in deciding the management strategy of these lesions, save time, and avoid complications. Methods Thirty-one patients undergoing PCI for STEMI under a pharmaco-invasive approach were prospectively recruited. The FFR measurements in 34 stenoses (≥70% diameter stenosis) were obtained immediately after PCI of the culprit stenosis and were repeated at a mean follow-up of 17.6 ± 3.55 (14-21) days. In addition, time to thrombolysis, time from symptom onset to PCI, left ventricular ejection fraction (LVEF), quantitative coronary angiographic measurements of the non-culprit stenoses, and thrombolysis in myocardial infarction (TIMI) flow were recorded. Results There was a significant change in FFR values at follow-up as compared to baseline (0.78 ± 0.08 (0.68-0.93) to 0.77 ± 0.08 (0.67-0.93)) (p = 0.014). In four of the lesions, the FFR values differed by >0.05 at follow-up. The follow-up FFR values led to a change in the management strategy in 5 out of 31 patients (15%) of the lesions. The TIMI flow, percentage diameter stenosis, minimum lumen diameter, and LVEF did not change. There were no predictors of this change in FFR values. Conclusions During the acute phase of STEMI, the severity of non-culprit coronary artery stenoses can not be reliably assessed by FFR. The prolonged jeopardized state of myocardium in pharmaco-invasive PCI as compared to primary PCI seems to be responsible.

Differential sensitivities to blood pressure variations in internal carotid and intracranial arteries: a numerical approach to stroke prediction

Stroke remains a global health concern, necessitating early prediction for effective management. Atherosclerosis-induced internal carotid and intra cranial stenosis contributes significantly to stroke risk. This study explores the relationship between blood pressure and stroke prediction, focusing on internal carotid artery (ICA) branches: middle cerebral artery (MCA), anterior cerebral artery (ACA), and their role in hemodynamics. Computational fluid dynamics (CFD) informed by the Windkessel model were employed to simulate patient-specific ICA models with introduced stenosis. Central to our investigation is the impact of stenosis on blood pressure, flow velocity, and flow rate across these branches, incorporating Fractional Flow Reserve (FFR) analysis. Results highlight differential sensitivities to blood pressure variations, with M1 branch showing high sensitivity, ACA moderate, and M2 minimal. Comparing blood pressure fluctuations between ICA and MCA revealed heightened sensitivity to potential reverse flow compared to ICA and ACA comparisons, emphasizing MCA's role. Blood flow adjustments due to stenosis demonstrated intricate compensatory mechanisms. FFR emerged as a robust predictor of stenosis severity, particularly in the M2 branch. In conclusion, this study provides comprehensive insights into hemodynamic complexities within major intracranial arteries, elucidating the significance of blood pressure variations, flow attributes, and FFR in stenosis contexts. Subject-specific data integration enhances model reliability, aiding stroke risk assessment and advancing cerebrovascular disease understanding.

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

Coronary physiologic assessment is performed to measure coronary pressure, flow, and resistance or their surrogates to enable the selection of appropriate management strategy and its optimization for patients with coronary artery disease. The value of physiologic assessment is supported by a large body of clinical data that has led to major recommendations in all practice guidelines. This expert consensus document aims to convey practical and balanced recommendations and future perspectives for coronary physiologic assessment for physicians and patients in the Asia-Pacific region, based on updated information in the field that includes both wire- and image-based physiologic assessment. This is Part 2 of the whole consensus document, which provides theoretical and practical information on physiologic indexes for specific clinical conditions and patient statuses.

Complete Percutaneous Coronary Revascularization in Acute Coronary Syndromes With Multivessel Coronary Disease: A Systematic Review

Multivessel disease (MVD) affects approximately 50% of patients with acute coronary syndromes (ACS) and is significantly burdened by poor outcomes and high mortality. It represents a clinical challenge in patient management and decision making and subtends an evolving research area related to the pathophysiology of unstable plaques and local or systemic inflammation. The benefits of complete revascularization are established in hemodynamically stable ACS patients with MVD, and guidelines provide some reference points to inform clinical practice, based on an evidence level that is solid for ST-segment elevation myocardial infarction and less robust for non-ST-segment elevation myocardial infarction and cardiogenic shock. However, several areas of uncertainty remain, such as the optimal timing for complete revascularization or the best guiding strategy for intermediate stenoses. We performed a systematic review of current evidence in the field of percutaneous revascularization in ACS and MVD, also including future perspectives from ongoing trials that will directly compare different timing strategies and investigate the role of invasive and noninvasive guidance techniques. (Complete percutaneous coronary revascularization in patients with acute myocardial infarction and multivessel disease; CRD42022383123).

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

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

Moving toward Precision Medicine in Acute Coronary Syndromes: A Multimodal Assessment of Non-Culprit Lesions

Patients with acute coronary syndrome and multivessel disease experience several recurrent adverse events that lead to poor outcomes. Given the complexity of treating these patients, and the extremely high risk of long-term adverse events, the assessment of non-culprit lesions becomes crucial. Recently, two trials have shown a possible clinical benefit into treat non-culprit lesions using a fraction flow reserve (FFR)-guided approach, compared to culprit-lesion-only PCI. However, the most recent FLOW Evaluation to Guide Revascularization in Multivessel ST-elevation Myocardial Infarction (FLOWER-MI) trial did not show a benefit of the use of FFR-guided PCI compared to an angiography-guided approach. Otherwise, intracoronary imaging using optical coherence tomography (OCT), intravascular ultrasound (IVUS), or near-infrared spectroscopy (NIRS) could provide both quantitative and qualitative assessments of non-culprit lesions. Different studies have shown how the characterization of coronary lesions with intracoronary imaging could lead to clinical benefits in these peculiar group of patients. Moreover, non-invasive evaluations of NCLs have begun to take ground in this context, but more insights through adequately powered and designed studies are needed. The aim of this review is to outline the available techniques, both invasive and non-invasive, for the assessment of multivessel disease in patients with STEMI, and to provide a systematic guidance on the assessment and approach to these patients.

Timing and modality of complete revascularization in patients presenting with ST-segment elevation myocardial infarction and multivessel coronary artery disease

Approximately half of the patients presenting with ST-segment elevation myocardial infarction have also significant atherosclerotic disease affecting coronary segments other than the infarct-related artery. Optimal management of residual lesions in this clinical setting has been a topic of intense research in the last decade. On the one hand, a large body of evidence has consistently shown the benefit of complete revascularization for the reduction of adverse cardiovascular outcomes. On the other hand, some crucial aspects such as the optimal timing or the best strategy of the complete treatment approach remain a matter of controversy. In this review, we aim to provide a thorough critical appraisal of the available literature regarding this topic, by discussing areas of relative certainty, gaps in the knowledge, approach to specific clinical subsets and future research directions.

Coronary microcirculation in nonculprit vessel territory in reperfused acute myocardial infarction

BACKGROUND

There is an ongoing debate on the extension of reperfusion-related microvascular damage (MVD) throughout the remote noninfarcted myocardial regions in patients with ST-elevation myocardial infarction (STEMI) that undergo primary percutaneous intervention (pPCI). The aim of this study was to elucidate the impact of reperfusion on remote microcirculatory territory by analyzing hemodynamic alterations in the nonculprit-vessel in relation to reperfusion.

METHODS

A total of 20 patients with STEMI undergoing pPCI were included. Peri-reperfusion temporal changes in hemodynamic parameters were obtained in angiographically normal nonculprit vessels before and 1-h after reopening of the culprit vessel. Intracoronary pressure and flow velocity data were compared using pairwise analyses (before and 1-h after reperfusion).

RESULTS

In the non-culprit vessel, compared to the pre-reperfusion state, mean resting average peak velocity (33.4 ± 9.4 to 25.0 ± 4.9 cm/s, P < 0.001) and mean hyperemic average peak velocity (53.5 ± 14.4 to 42.1 ± 10.66 cm/s, P = 0.001) significantly decreased; whereas baseline (3.2 ± 1.0 to 4.0 ± 1.0 mmHg.cm^-1.s, P < 0.001) and hyperemic microvascular resistance (HMR) (1.9 ± 0.6 to 2.4 ± 0.7 mmHg.cm^-1.s, P < 0.001) and mean zero flow pressure (Pzf) values (32.5 ± 6.9 to 37.6 ± 8.3 mmHg, P = 0.003) significantly increased 1-h after reperfusion. In particular, the magnitude of changes in HMR and Pzf values following reperfusion were more prominent in patients with larger infarct size and with higher extent of MVD in the culprit vessel territory.

CONCLUSION

Reperfusion-related microvascular injury extends to involve remote myocardial territory in relation to the magnitude of the adjacent infarction and infarct-zone MVD. (GUARD Clinical TrialsNCT02732080).

Complete revascularization in acute myocardial infarction: a clinical review

In patients with ST segment elevation and non-ST elevation myocardial infarction (MI), multivessel (MV) coronary artery disease is found in approximately 50%, leading to worse clinical outcomes. Recent data have suggested that complete revascularization with MV percutaneous coronary intervention is associated with a reduced risk of major adverse cardiovascular events as compared to culprit vessel-only revascularization. However, the optimal timing of MV intervention, appropriate non-culprit lesion assessment, and the best revascularization strategy in specific subsets such as cardiogenic shock remain to be established. This review article summarizes current evidence on revascularization strategies in patients with acute MI and MV disease.

Management of Non-Culprit Lesions in STEMI Patients with Multivessel Disease

Multivessel disease is observed in approximately 50% of patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Data from randomized clinical trials has shown that complete revascularization in the STEMI setting improves clinical outcomes by reducing the risk of reinfarction and urgent revascularization. However, the timing and modality of revascularization of non-culprit lesions are still debated. PCI of non-culprit lesions can be performed during the index primary PCI or as a staged procedure and can be guided by angiography, functional assessment, or intracoronary imaging. In this review, we summarize the available evidence about the management of non-culprit lesions in STEMI patients with or without cardiogenic shock.

Quantitative flow ratio vs. angiography-only guided PCI in STEMI patients: one-year cardiovascular outcomes

BACKGROUND

Coronary physiology-guided PCIs are recommended worldwide. However, invasive coronary physiology methods prolong the procedure, create additional risks for the patients, and prolong the fluoroscopy time for an interventional cardiologist. Otherwise, there is a noninvasive coronary physiology evaluation method, QFR, that can be safely used even in STEMI patients.

METHODS

A total of 198 patients admitted with STEMI and at least one intermediate (35-75%) diameter stenosis other than the culprit artery between July 2020 and June 2021 were prospectively included in this single-center study. All patients were randomized into one of two groups (1 - QFR-guided PCI; 2 - visual-estimation-only guided PCI). A 12-month follow-up with echocardiography, exercise stress test, and quality of life evaluation was performed in all included patients. For the QOF evaluation, the Seattle Angina Score Questionnaire was chosen. Statistical analysis was performed using the Kolmogorov-Smirnov test, Student's t-test, Mann-Whitney U test, Pearson's chi-squared test and Kaplan-Meier estimator.

RESULTS

Ninety-eight (49.5%) patients were randomized to the first group, and 100 (50.5%) patients were included in the second group. Statistically, significantly more patients had a medical history of dyslipidemia (98 vs. 91, p = 0.002) and slightly better left ventricular ejection fraction (42.21 ± 7.88 vs. 39.45 ± 9.62, p = 0.045) in the QFR group. Six fewer patients required non-culprit artery revascularization within the 12-month FU in the QFR group (1.02% vs. 6%, p = 0.047). Survival analysis proved that patients in the Angio group had a more than 6-fold greater risk for death within a 12-month period after MI (OR 6.23, 95% CI 2.20-17.87, p = 0.006), with the highest mortality risk within the first two months after initial treatment.

CONCLUSION

Using QFR in non-culprit lesions in patients with ST-elevation myocardial infarction reduces mortality and revascularization at the 12-month follow-up and improves the quality of life of the patient.

TRIAL REGISTRATION

The study was approved by the Regional Bioethical Committee and conducted under the principles of the Helsinki Declaration and local laws and regulations.

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

AIMS

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

METHODS AND RESULTS

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

CONCLUSION

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

Clinical Outcome of Revascularization Deferral With Instantaneous Wave-Free Ratio and Fractional Flow Reserve: A 5-Year Follow-Up Substudy From the iFR-SWEDEHEART Trial

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.

Myocardial mass affects diagnostic performance of non-hyperemic pressure-derived indexes in the assessment of coronary stenosis

Background Several non-hyperemic pressure-derived Indexes (NHPI) have been introduced for the assessment of coronary stenosis, showing a good correlation with fractional flow reserve (FFR). Notably, either the assessment of NHPI during adenosine administration (NHPI_ADO) or the Hybrid Approach (NHPI_HA), combining NHPI with FFR, have been showed to increase the accuracy of such indexes. It remains unclear whether diagnostic performance might be affected by the extent of the subtended myocardial mass.

METHODS

We enrolled consecutive patients with an intermediate coronary stenosis assessed with NHPI and FFR. NHPI were also measured during adenosine (ADO) administration (NHPI_ADO). The amount of jeopardized myocardium was assessed using the Duke Jeopardy Score (DJS). With FFR as reference, we assessed the accuracy of NHPI, NHPI_ADO and NHPI_HA according to the extent of the subtended myocardium.

RESULTS

One-hundred-seventy stenoses from 151 patients were grouped according to the DJS as follows: A) Small Extent (SE, n = 82); B) Moderate Extent (ME, n = 53); C) Large Extent (LE, n = 35). As compared with FFR, NHPI showed a significantly different accuracy, as assessed by the Youden's index, according to the extent of the jeopardized myocardium (SE: 0.39 ± 0.05, ME: 0.68 ± 0.06, LE: 0.28 ± 0.06, p < 0.001). Conversely, both the NHPI_ADO (SE: 0.76 ± 0.02, ME: 0.88 ± 0.02, LE: 0.82 ± 0.02, p = 0.72) and NHPI_HA (SE: 0.82 ± 0.07, ME: 0.84 ± 0.02, LE: 0.88 ± 0.02, p = 0.70) allowed for a better diagnostic accuracy regardless of the amount of myocardium subtended.

CONCLUSIONS

Diagnostic performance of NHPI might be affected by the extent of myocardial territory subtended by the coronary stenosis. A hybrid approach might be useful to overcome this limitation.

Microcirculation function assessment in acute myocardial infarction: A systematic review of microcirculatory resistance indices

Background

Up to 50% of acute myocardial infarction (MI) patients present with microvascular dysfunction, after a successful percutaneous coronary intervention (PCI), which leads to worse clinical outcomes. The main purpose of this study is to provide a critical appraisal of the emerging role of invasive microvascular resistance indices in the MI setting, using the index of microcirculatory resistance (IMR), hyperemic microvascular resistance (HMR) and zero-flow pressure (Pzf).

Methods

We systematically explored relevant studies in the context of MI that correlated microcirculation resistance indices with microvascular dysfunction on cardiac magnetic resonance (CMR), microvascular dysfunction occurring in infarct related arteries (IRA) and non-IRA and its relation to clinical outcomes.

Results

The microcirculation resistance indices correlated significantly with microvascular obstruction (MVO) and infarct size (IS) on CMR. Although HMR and Pzf seem to have better diagnostic accuracy for MVO and IS, IMR has more validation data. Although, both IMR and HMR were independent predictors of adverse cardiovascular events, HMR has no validated cut-off value and data is limited to small observational studies. The presence of microvascular dysfunction in non-IRA does not impact prognosis.

Conclusion

Microvascular resistance indices are valuable means to evaluate microcirculation function following MI. Microvascular dysfunction relates to the extent of myocardial damage and clinical outcomes after MI.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021228432], identifier [CRD42021228432].

Diagnostic Performance of On-Site Computed Tomography Derived Fractional Flow Reserve on Non-Culprit Coronary Lesions in Patients with Acute Coronary Syndrome

The role of coronary computed tomography angiography (CCTA) derived fractional flow reserve (CT-FFR) in the assessment of non-culprit lesions (NCL) in patients with acute coronary syndrome (ACS) is debated. In this prospective clinical study, a total of 68 ACS patients with 89 moderate (30−70% diameter stenosis) NCLs were enrolled to evaluate the diagnostic accuracy of on-site CT-FFR compared to invasive fractional flow reserve (FFRi) and dobutamine stress echocardiography (DSE) as reference standards. CT-FFR and FFRi values ≤0.80, as well as new or worsening wall motion abnormality in ≥2 contiguous segments on the supplying area of an NCL on DSE, were considered positive for ischemia. Sensitivity, specificity, positive, and negative predictive value of CT-FFR relative to FFRi and DSE were 51%, 89%, 75%, and 74% and 37%, 77%, 42%, and 74%, respectively. CT-FFR value (β = 0.334, p < 0.001) and CT-FFR drop from proximal to distal measuring point [(CT-FFR drop), β = −0.289, p = 0.002)] were independent predictors of FFRi value in multivariate linear regression analysis. Based on comparing their receiver operating characteristics area under the curve (AUC) values, CT-FFR value and CT-FFR drop provided better discriminatory power than CCTA-based minimal lumen diameter stenosis to distinguish between an NCL with positive and negative FFRi [0.77 (95% Confidence Intervals, CI: 0.67−0.86) and 0.77 (CI: 0.67−0.86) vs. 0.63 (CI: 0.52−0.73), p = 0.029 and p = 0.043, respectively]. Neither CT-FFR value nor CT-FFR drop was predictive of regional wall motion score index at peak stress (β = −0.440, p = 0.441 and β = 0.403, p = 0.494) or was able to confirm ischemia on the territory of an NCL revealed by DSE (AUC = 0.54, CI: 0.43−0.64 and AUC = 0.55, CI: 0.44−0.65, respectively). In conclusion, on-site CT-FFR is superior to conventional CCTA-based anatomical analysis in the assessment of moderate NCLs; however, its diagnostic capacity is not sufficient to make it a gatekeeper to invasive functional evaluation. Moreover, based on its comparison with DSE, CT-FFR might not yield any information on the microvascular dysfunction in the territory of an NCL.

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

Background

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

Objectives

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

Methods

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

Results

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

Conclusions

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

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

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

Fractional flow reserve in patients with type 1 or type 2 non-ST elevation acute myocardial infarction

AIMS

We assessed a combined strategy of fractional flow reserve (FFR) plus angiography in stratifying cardiovascular risk in patients with type 1 myocardial infarction (T1MI) or type 2 (T2MI) non-ST elevation acute myocardial infarction (NSTEMI).

METHODS

A cohort of 150 NSTEMI patients were prospectively studied. Clinical and angiographic features guided the identification of T1MI vs T2MI and the treatment of culprit lesions. Subsequently, T1MI patients underwent FFR evaluation of nonculprit stenoses. In T2MI patients all angiographically significant stenoses were evaluated by FFR. FFR < 0.80 was an indication for revascularization. Based on FFR results, two groups were compared: patients with all lesions ≥0.80 ('defer' group, n = 87) and those with at least one lesion <0.80 ('perform' group, n = 63). The primary end point was the composite of all-cause death, nonfatal MI and unplanned coronary revascularization.

RESULTS

Median clinical follow-up was of 35 months (interquartile range 14-44). Primary end-point rates in the 'defer' and 'perform' groups were 14.5% and 30.0% at 12 months and 28% and 46% at 36 months, respectively (log-rank test: at 1 year, P = 0.007; at the end of follow-up P = 0.014). On multivariable analysis, chronic kidney disease (HR 3.50, 95% CI: 1.89-6.46, P = 0.0001) and FFR group ('perform' vs 'defer': HR 1.75 95% CI: 1.01-3.04, P = 0.046) were independent predictors of adverse events.

CONCLUSIONS

In NSTEMI patients, our results indicated that FFR combined with angiography allowed the treatment of nonfunctional significant lesions to be safely deferred and patient cardiovascular risk to be identified.

Correlation and Relative Prognostic Value of Fractional Flow Reserve and Pd/Pa of Nonculprit Lesions in ST-Segment-Elevation Myocardial Infarction

BACKGROUND

The applicability of resting indices to guide noninfarct-related artery revascularization in ST-elevation myocardial infarction is unknown.

METHODS

We analyzed the correlation and prognostic value of fractional flow reserve (FFR) and resting distal coronary to aortic pressure ratio (Pd/Pa) in all patients of the Compare-Acute trial in whom, after successful primary percutaneous coronary intervention, the noninfarct-related artery was interrogated by both and treated medically. The treating cardiologist was blinded to these values. The primary end point was the composite of target vessel (interrogated noninfarct-related artery) related nonfatal target vessel myocardial infarction and target vessel repeat revascularization at 36 months.

RESULTS

Five hundred seventeen patients (665 vessels) were included. On receiver-operating characteristic analysis, the optimal Pd/Pa cut off for FFR≤0.80 was 0.905 (C statistic: 0.894). The diagnostic accuracy of Pd/Pa was 80.15% (95% CI, 76.91%-83.12%) with respect to FFR. During the 36-month follow-up, 130 target vessel revascularization and 14 target vessel myocardial infarction occurred. FFR and Pd/Pa had a diagnostic accuracy to predict these events of 62.86% (95% CI, 59.06%-66.54%) and 56.84% (95% CI, 52.98%-60.64%), respectively (P=0.20). When they were discrepant, FFR was significantly better than Pd/Pa in identifying which vessels could be safely deferred (P=0.048).

CONCLUSIONS

Immediately after successful primary percutaneous coronary intervention, resting Pd/Pa has a diagnostic accuracy of 80% with respect to FFR measured in the noninfarct-related artery. FFR is not significantly superior in predicting target vessel myocardial infarction and target vessel revascularization during 36 months of follow-up but, in case FFR and Pd/Pa are discrepant, FFR is superior in identifying which nonculprit vessels can be safely deferred. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01399736.

Fractional Flow Reserve: Patient Selection and Perspectives

The aim of this review was to discuss the current practice and patient selection for invasive FFR, new techniques to estimate invasive FFR and future of coronary physiology tests. We elaborate on the indication and application of FFR and on the contraindications and concerns in certain patient populations.

Instantaneous wave-free ratio for guiding treatment of nonculprit lesions in patients with acute coronary syndrome: A retrospective study

BACKGROUND

The aim of this study was to analyze the feasibility of a physiological coronary evaluation with the instantaneous wave-free ratio (iFR) of nonculprit lesions in patients with acute coronary syndrome (ACS) successfully revascularized.

METHODS

A multicenter registry including patients of four high-volume PCI centers with ACS and underwent successful revascularization of the culprit vessel and had other nonculprit lesions that were physiologically evaluated with the iFR between January 2017 and December 2019. The primary endpoint was a composite of cardiac death, nonfatal myocardial infarction, probable or definitive stent thrombosis and new revascularization (MACEs).

RESULTS

A total of 356 patients with 472 nonculprit lesions were included. The mean age was 66 ± 11 years. The clinical presentation was ACS without persistent ST-segment elevation (NSTE-ACS) in 235 patients (66%) and ST-segment elevation myocardial infarction (STEMI) in 121 patients (34%). After a median follow-up period of 21 (14-30) months, the primary endpoint occurred in 32 patients (9%). There were no differences in outcomes regarding clinical presentation (NSTEMI vs. NSTE-ACS, 9.1 vs. 8.9%, p_adj  = 0.570) or iFR induced treatment strategy (patients with all lesions revascularized vs. patients with at least one lesion with an iFR > 0.89 deferred for revascularization, 10.5 vs. 8.4%, p_adj  = 0.476).

CONCLUSIONS

The use of the iFR to guide percutaneous coronary intervention decision making in nonculprit lesions seems to be feasible, with an acceptable percentage of MACEs at the mid-term follow-up. Patients with deferred revascularization of lesions without physiological significance and patients undergoing complete revascularization had a similar risk of MACEs.

A clinical trial comparing complete revascularization at the time of primary percutaneous coronary intervention versus during the index hospital admission in patients with multi-vessel coronary artery disease and STEMI uncomplicated by cardiogenic shock

OBJECTIVE

In this study, we aimed to compare major adverse cardiac and cerebrovascular events (MACCE), defined as a composite of death, stroke, myocardial infarction and symptom-induced revascularization, and mortality within one year of randomization between two strategies; complete revascularization including non-culprit lesions percutaneous coronary intervention (PCI) during primary PCI (PPCI) versus complete revascularization during the same hospital admission in patients with multi-vascular coronary artery disease (MVD) presenting with ST-elevation myocardial infarction (STEMI) uncomplicated by cardiogenic shock.

METHODS

We randomized in a 1: 1 manner 100 patients with MVD and STEMI uncomplicated by cardiogenic shock who had undergone successful culprit-lesion PCI to either a strategy of complete revascularization with PCI of angiographically significant non-culprit lesions in the index PPCI procedure or to a strategy of complete revascularization during a second procedure that took place during the same hospital admission.

RESULTS

The first primary outcome was death within a timeframe of one year and the second a composite of MACCE within a year following complete revascularization. Of the total number of patients monitored, 4% in each of the two groups was associated with the first primary outcome (p=0.984) and the second primary outcome in 6% (p=0.970). There was no statistical difference between outcomes in the two groups.

CONCLUSION

Among patients with MVD and STEMI uncomplicated by cardiogenic shock, there was no difference regarding outcomes when using a strategy of complete revascularization of non-culprit lesions during PPCI or the same hospital admission.

Prognostic Impact of Pancoronary Quantitative Flow Ratio Assessment in Patients Undergoing Percutaneous Coronary Intervention for Acute Coronary Syndromes

BACKGROUND

Quantitative flow ratio (QFR) has been introduced as a novel angiography-based modality for fast hemodynamic assessment of coronary artery lesions and validated against fractional flow reserve. This study sought to define the prognostic role of pancoronary QFR assessment in patients with acute coronary syndrome (ACS) including postinterventional culprit and nonculprit vessels.

METHODS

In a total of 792 patients with ACS (48.6% ST-segment-elevation ACS and 51.4% non-ST-segment-elevation ACS), QFR analyses of postinterventional culprit (n=792 vessels) and nonculprit vessels (n=1231 vessels) were post hoc performed by investigators blinded to clinical outcomes. The follow-up comprised of major adverse cardiovascular events, including all-cause mortality, nonfatal myocardial infarction, and ischemia-driven coronary revascularization within 2 years after the index ACS event.

RESULTS

Major adverse cardiovascular events as composite end point occurred in 99 patients (12.5%). QFR with an optimal cutoff value of 0.89 for postinterventional culprit vessels and 0.85 for nonculprit vessels emerged as independent predictor of major adverse cardiovascular events after ACS (nonculprit arteries: adjusted odds ratio, 3.78 [95% CI, 2.21-6.45], P<0.001 and postpercutaneous coronary intervention culprit arteries: adjusted odds ratio, 3.60 [95% CI, 2.09-6.20], P<0.001).

CONCLUSIONS

The present study for the first time demonstrates the prognostic implications of a pancoronary angiography-based functional lesion assessment in patients with ACS. Hence, QFR offers a novel tool to advance risk stratification and guide therapeutic management after ACS.

Functionally Complete Coronary Revascularisation in Patients Presenting with ST-elevation MI and Multivessel Coronary Artery Disease

Up to half of patients undergoing primary percutaneous coronary intervention of a culprit stenosis in the context of the ST-elevation MI may present with multivessel disease. The presence of non-culprit stenoses have been shown to affect the outcomes of these patients, and the results of the more recent randomised trials highlight the importance of complete coronary revascularisation. In this paper, the authors review the main trials published on the topic and discuss tools for the assessment of non-culprit stenoses, while considering the right time for carrying out a complete coronary revascularisation.

Multivessel PCI Guided by FFR or Angiography for Myocardial Infarction

BACKGROUND

In patients with ST-elevation myocardial infarction (STEMI) who have multivessel disease, percutaneous coronary intervention (PCI) for nonculprit lesions (complete revascularization) is superior to treatment of the culprit lesion alone. However, whether complete revascularization that is guided by fractional flow reserve (FFR) is superior to an angiography-guided procedure is unclear.

METHODS

In this multicenter trial, we randomly assigned patients with STEMI and multivessel disease who had undergone successful PCI of the infarct-related artery to receive complete revascularization guided by either FFR or angiography. The primary outcome was a composite of death from any cause, nonfatal myocardial infarction, or unplanned hospitalization leading to urgent revascularization at 1 year.

RESULTS

The mean (±SD) number of stents that were placed per patient for nonculprit lesions was 1.01±0.99 in the FFR-guided group and 1.50±0.86 in the angiography-guided group. During follow-up, a primary outcome event occurred in 32 of 586 patients (5.5%) in the FFR-guided group and in 24 of 577 patients (4.2%) in the angiography-guided group (hazard ratio, 1.32; 95% confidence interval, 0.78 to 2.23; P = 0.31). Death occurred in 9 patients (1.5%) in the FFR-guided group and in 10 (1.7%) in the angiography-guided group; nonfatal myocardial infarction in 18 (3.1%) and 10 (1.7%), respectively; and unplanned hospitalization leading to urgent revascularization in 15 (2.6%) and 11 (1.9%), respectively.

CONCLUSIONS

In patients with STEMI undergoing complete revascularization, an FFR-guided strategy did not have a significant benefit over an angiography-guided strategy with respect to the risk of death, myocardial infarction, or urgent revascularization at 1 year. However, given the wide confidence intervals for the estimate of effect, the findings do not allow for a conclusive interpretation. (Funded by the French Ministry of Health and Abbott; FLOWER-MI ClinicalTrials.gov number, NCT02943954.).

Adenosine-Induced Coronary Steal Is Observed in Patients Presenting With ST-Segment-Elevation Myocardial Infarction

Background Adenosine is used to treat no-reflow in the infarct-related artery (IRA) during ST-segment-elevation myocardial infarction intervention. However, the physiological effect of adenosine in the IRA is variable. Coronary steal-a reduction of blood flow to the distal coronary bed-can occur in response to adenosine and this is facilitated by collaterals. We investigated the effects of adenosine on coronary flow reserve (CFR) in patients presenting with ST-segment-elevation myocardial infarction to better understand the physiological mechanism underpinning the variable response to adenosine. Methods and Results Pressure-wire assessment of the IRA after percutaneous coronary intervention was performed in 93 patients presenting with ST-segment-elevation myocardial infarction to calculate index of microvascular resistance, CFR, and collateral flow index by pressure. Modified collateral Rentrop grade to the IRA was recorded, as was microvascular obstruction by cardiac magnetic resonance imaging. Coronary steal (CFR <0.9), no change in flow (CFR=0.9-1.1), and hyperemic flow (CFR >1.1) after adenosine occurred in 19 (20%), 15 (16%), and 59 (63%) patients, respectively. Patients with coronary steal had higher modified Rentrop score to the IRA (1 [0, 1.75] versus 0 [0, 1], P<0.001) and a higher collateral flow index by pressure (0.25±0.10 versus 0.15±0.10, P=0.004) than the hyperemic group. The coronary steal group also had significantly higher index of microvascular resistance (61.68 [28.13, 87.04] versus 23.93 [14.67, 37.00], P=0.006) and had more disease (stenosis >50%) in the donor arteries (52.63% versus 22.03%, P=0.02) than the hyperemic group. Conclusions Adenosine-induced coronary steal may be responsible for a reduction in coronary flow reserve in a proportion of patients presenting with ST-segment-elevation myocardial infarction. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03145194. URL: https://www.isrctn.com; Unique identifier: ISRCTN3176727.

Management of Multivessel Disease and Physiology Testing in ST Elevation Myocardial Infarction

For decades, advances in ST elevation myocardial infarction (STEMI) care have been driven by timely reperfusion of the occluded culprit vessel. More recently, however, the focus has shifted to revascularization of nonculprit vessels in STEMI patients. Five landmark randomized trials, all published in the past 7 years, have highlighted the importance of complete revascularization in STEMI treatment. This review focuses on evidence-based management of STEMI in the setting of multivessel disease, highlighting contemporary data that investigate the impact of complete revascularization.

Diagnostic accuracy of 3D deep-learning-based fully automated estimation of patient-level minimum fractional flow reserve from coronary computed tomography angiography

AIMS

Although deep-learning algorithms have been used to compute fractional flow reserve (FFR) from coronary computed tomography angiography (CCTA), no study has achieved 'fully automated' (i.e. free from human input) FFR calculation using deep-learning algorithms. The purpose of the study was to evaluate the accuracy of a fully automated 3D deep-learning model for estimating minimum FFR from CCTA data, with invasive FFR as the reference standard.

METHODS AND RESULTS

This retrospective study of 1052 patients included 131 patients whose CCTA studies showed 30-90% stenosis and underwent invasive FFR (abnormal FFR observed in 72/131, 55%), and 921 patients who underwent clinically indicated CCTA without invasive FFR. We designed a fully automated 3D deep-learning model that inputs CCTA data and outputs minimum FFR without requiring human input. The model comprised a series of deep-learning algorithms: a conditional generative adversarial network, a 3D convolutional ladder network, and two independent neural networks with integrated virtual adversarial training. We used Monte Carlo cross-validation to evaluate the accuracy of the model for estimating FFR, with invasive FFR as the reference standard. The deep-learning FFR achieved area under the receiver-operating characteristic curve of 0.78 for detection of abnormal FFR; and was significantly higher than for visually determined CCTA >50% stenosis (area under the curve = 0.56). The deep-learning FFR model achieved 76% accuracy for detecting abnormal FFR, with sensitivity of 85% (79-89%) and specificity of 63% (54-70%).

CONCLUSION

The 3D deep-learning model, which performs fully automatic estimation of minimum FFR from cardiac CT data, achieved 76% accuracy in detecting abnormal FFR.

Feasibility and diagnostic reliability of quantitative flow ratio in the assessment of non-culprit lesions in acute coronary syndrome

Several studies have demonstrated the feasibility and safety of hemodynamic assessment of non-culprit coronary arteries in setting of acute coronary syndromes (ACS) using fractional flow reserve (FFR) measurements. Quantitative flow ratio (QFR), recently introduced as angiography-based fast FFR computation, has been validated with good agreement and diagnostic performance with FFR in chronic coronary syndromes. The aim of this study was to assess the feasibility and diagnostic reliability of QFR assessment during primary PCI. A total of 321 patients with ACS and multivessel disease, who underwent primary PCI and were planned for staged PCI of at least one non-culprit lesion were enrolled in the analysis. Within this patient cohort, serial post-hoc QFR analyses of 513 non-culprit vessels were performed. The median time interval between primary and staged PCI was 49 [42–58] days. QFR in non-culprit coronary arteries did not change between acute and staged measurements (0.86 vs 0.87, p = 0.114), with strong correlation (r = 0.94, p ≤ 0.001) and good agreement (mean difference -0.008, 95%CI -0.013–0.003) between measurements. Importantly, QFR as assessed at index procedure had sensitivity of 95.02%, specificity of 93.59% and diagnostic accuracy of 94.15% in prediction of QFR ≤ 0.80 at the time of staged PCI. The present study for the first time confirmed the feasibility and diagnostic accuracy of non-culprit coronary artery QFR during index procedure for ACS. These results support QFR as valuable tool in patients with ACS to detect further hemodynamic relevant lesions with excellent diagnostic performance and therefore to guide further revascularisation therapy.

ADDED Index or percentage diameter of residual coronary stenosis to risk-stratify patients presenting with STEMI

BACKGROUND

We compared the prognostic value of the ADDED Index with visually estimated diameter (DS) of residual coronary stenosis (RS) in STEMI patients after successful PCI of the culprit lesion. Even though associated with a positive outcome, the functional assessment of non-culprit stenosis remains largely underused, especially in STEMI patients. The Angiography-DeriveD hEmoDynamic index (ADDED index) showed high accuracy to predict FFR and it might be used to better guide the diagnostic and therapeutic work-up of such patients.

METHODS

We retrospectively included 596 patients grouped on the basis of either the ADDED Index (ADDED Negative (<2.23, n = 153) vs ADDED Positive (≥2.23, n = 129)) or the DS of the RS (RS Negative (<50%, n = 177) vs RS Positive (≥50%, n = 105)). Patients without any RS served as control (n = 314). Primary endpoints were: 1) major adverse cardiac events (MACE), composite of all-cause death, myocardial infarction (MI), clinically driven revascularizations (CDR); 2) non-culprit vessel oriented clinical events (VOCE), composite of all-cause death, non-culprit vessel related MI and CDR.

RESULTS

At 24 months the rate of both MACE and VOCE was significantly higher in both the ADDED Positive and RS Positive groups. However, differently from patients in whom complete revascularization was deferred on the basis of the angiography (RS Negative), no additional risk was found for patients in the ADDED Negative group.

CONCLUSIONS

In STEMI patients with MVD deferring treatment of RS on the basis of the ADDED index, rather than the visually estimated DS, is associated with a favorable clinical outcome.

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

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