Validation of virtual fractional flow reserve pullback curves.

BACKGROUND: Angiography-derived fractional flow reserve (virtual FFR) has shown excellent diagnostic performance compared with wire-based FFR. However, virtual FFR pullback curves have not been validated yet. OBJECTIVES: To validate the accuracy of virtual FFR pullback curves compared to wire-based FFR pullbacks and to assess their clinical utility using patient-reported outcomes. METHODS: Pooled analysis of two prospective studies, including patients with hemodynamically significant (FFR ≤ 0.80) coronary artery disease (CAD). Virtual and wire-based FFR pullbacks were compared to assess the accuracy of virtual pullbacks to characterize CAD as focal or diffuse. Pullbacks were analyzed visually and quantitatively using the pullback pressure gradient (PPG). Patients underwent PCI, and the Seattle Angina Questionnaire (SAQ) was administered at 3-month follow-up. RESULTS: A total of 298 patients (300 vessels) with both virtual and wire-based pullbacks who underwent PCI were included in the analysis. The mean age was 61.8 ± 8.8, and 15% were female. The agreement on the visual adjudication of the CAD pattern was fair (Cohen's Kappa: 0.31, 95% confidence interval: 0.18-0.45). The mean PPG were 0.65 ± 0.18 from virtual pullbacks and 0.65 ± 0.13 from wire-based pullbacks (r = 0.68, mean difference 0, limits of agreement -0.27 to 0.28). At follow-up, patients with high virtual PPG (>0.67) had higher SAQ angina frequency scores (i.e., less angina) than those with low virtual PPG (SAQ scores 92.0 ± 14.3 vs. 85.5 ± 23.1, p = 0.022). CONCLUSION: Virtual FFR pullback curves showed moderate agreement with wire-based FFR pullbacks. Nonetheless, patients with focal disease based on virtual PPG reported greater improvement in angina after PCI.

Impact of vessel volume on thermodilution measurements in patients with coronary microvascular dysfunction.

BACKGROUND: Two invasive methods are available to estimate microvascular resistance: bolus and continuous thermodilution. Comparative studies have revealed a lack of concordance between measurements of microvascular resistance obtained through these techniques. AIMS: This study aimed to examine the influence of vessel volume on bolus thermodilution measurements. METHODS: We prospectively included patients with angina with non-obstructive coronary arteries (ANOCA) undergoing bolus and continuous thermodilution assessments. All patients underwent coronary CT angiography to extract vessel volume. Coronary microvascular dysfunction was defined as coronary flow reserve (CFR) < 2.0. Measurements of absolute microvascular resistance (in Woods units) and index of microvascular resistance (IMR) were compared before and after volumetric adjustment. RESULTS: Overall, 94 patients with ANOCA were included in this study. The mean age was 64.7 ± 10.8 years, 48% were female, and 19% had diabetes. The prevalence of CMD was 16% based on bolus thermodilution, while continuous thermodilution yielded a prevalence of 27% (Cohen's Kappa 0.44, 95% CI 0.23-0.65). There was no correlation in microvascular resistance between techniques (r = 0.17, 95% CI -0.04 to 0.36, p = 0.104). The adjustment of IMR by vessel volume significantly increased the agreement with absolute microvascular resistance derived from continuous thermodilution (r = 0.48, 95% CI 0.31-0.63, p < 0.001). CONCLUSIONS: In patients with ANOCA, invasive methods based on coronary thermodilution yielded conflicting results for the assessment of CMD. Adjusting IMR with vessel volume improved the agreement with continuous thermodilution for the assessment of microvascular resistance. These findings strongly suggest the importance of considering vessel volume when interpreting bolus thermodilution assessment.

[Can smart devices and AI in cardiology improve clinical practice?] / Les dispositifs intelligents et l'IA en cardiologie peuvent-ils améliorer la pratique clinique ?

Remote monitoring is becoming increasingly popular among healthcare professionals and patients for diagnosing and treating heart disease. Several smart devices connected to smartphones have been developed and validated in recent years, but their clinical use is still limited. Significant advances in the field of artificial intelligence (AI) are also revolutionizing several fields, yet the impact that these innovations could have on routine clinical practice is still unknown. We review the evidence and uses of the main smart devices currently available as well as the latest applications of AI in the field of cardiology, with the aim to ultimately evaluate the potential of this technology to transform modern clinical practice.

Le monitorage à distance devient de plus en plus populaire parmi les praticiens de la santé pour le diagnostic et la surveillance des maladies cardiaques. Plusieurs dispositifs « intelligents ¼ et connectés aux smartphones ont été développés et validés durant ces dernières années, mais leur utilisation clinique est toujours limitée. Bien que les progrès de l'intelligence artificielle (IA) soient en train de révolutionner plusieurs domaines, l'impact que ces innovations pourront avoir dans le monde médical est toujours inconnu. Le but de cet article est de passer en revue les principaux dispositifs disponibles et de comprendre les applications actuelles de l'IA en cardiologie, afin de mieux saisir dans quelle mesure ils sont susceptibles de transformer notre pratique clinique quotidienne.

Diagnostic performance of angiography-derived fractional flow reserve in patients with NSTEMI.

Noninvasive methods of estimating invasively measured fractional flow reserve (FFRinvasive ) are actively being explored, aiming to avoid the use of an invasive pressure wire and the administration of hyperemia-inducing drugs. Coronary angiography-derived FFR (FFRangio ) has already demonstrated its diagnostic performance in the context of stable coronary artery disease. However, its applicability in the context of non-ST-segment elevation myocardial infarction (NSTEMI) has yet to be established. We sought to determine the diagnostic performance of FFRangio exclusively in patients presenting with NSTEMI. We performed a prospective, single-center, single-arm, double-blinded study comparing FFR calculated by FFRangio to FFRinvasive in NSTEMI patients. FFRinvasive was measured in all angiographically intermediate lesions (30%-70% stenosis) and was then compared to FFRangio which was calculated at the same position, by a blinded operator. The primary endpoints were the sensitivity and specificity of FFRangio for predicting FFRinvasive using a cut-off value of ≤0.80. Among 100 NSTEMI patients who were screened, 46 patients with 60 vessels in total underwent FFRinvasive and were included in the study. The mean value of FFRinvasive was 0.83 ± 0.3 with 22 (36%) being ≤0.80 while the mean FFRangio was 0.82 ± 0.1 with 22 (36%) being ≤0.80. FFRangio exhibited a sensitivity of 95.5%, a specificity of 97.4%, and a diagnostic accuracy of 96.7%. FFRangio can precisely and noninvasively estimate FFRinvasive in acute coronary syndromes and may have a role in guiding treatment decisions related to angiographically intermediate coronary lesions in this context. WHAT IS KNOWN: FFRangio has demonstrated its diagnostic performance in validation studies, as a noninvasive and cost-effective method in the context of stable coronary artery disease but its performance has never been exclusively evaluated in NSTEMI patients. WHAT IS NEW: The present prospective single-center study demonstrates the excellent diagnostic performance of FFRangio in detecting functionally significant coronary artery stenosis in the setting of NSTEMI, providing more confidence in utilizing FFRangio in this population, avoiding the risk of an invasive pressure wire and the administration of hyperemia-inducing drugs. WHAT IS NEXT: Future randomized trials evaluating FFRangio -guided treatment of coronary artery disease (stable or ACS) are now needed to definitively establish the role of FFRangio in the physiological assessment of coronary lesions.

Narrow complex tachycardia with discordant 12-lead RP intervals.

We present a case of supraventricular tachycardia (SVT) with discordant RP intervals on 12­lead ECG, rendering the diagnosis initially challenging. However, clues present on the ECG during SVT along with an ECG in sinus rhythm helped to elucidate the mechanism and the underlying diagnosis.

[Cardiology]. / Cardiologie.

Significant advances have been made in 2021 in the areas of interventional cardiology, heart failure, cardiac imaging, electrophysiology and congenital heart disease. In addition to improving the screening, diagnosis and management of many heart diseases, these advances will change our daily practice. Moreover, the European Society of Cardiology has updated its guidelines on heart failure, valve disease, cardiac pacing and cardiovascular disease prevention. As in previous years, members of the Cardiology division of Lausanne University Hospital (CHUV) came together to select and present to you the papers that they considered to be the most important of the past year.

De nombreux progrès ont été réalisés en 2021 dans les domaines de la cardiologie interventionnelle, de l'insuffisance cardiaque, de l'imagerie cardiaque, de l'électrophysiologie et des cardiopathies congénitales. En plus d'améliorer le dépistage, le diagnostic et la prise en charge de nombreuses cardiopathies, ces avancées vont faire évoluer notre pratique quotidienne. Par ailleurs, la Société européenne de cardiologie a mis à jour ses recommandations portant sur l'insuffisance cardiaque, les valvulopathies, la stimulation cardiaque et la prévention des maladies cardiovasculaires. Comme les années précédentes, les membres du Service de cardiologie du CHUV se sont réunis pour sélectionner et vous présenter les travaux qui leur ont semblé être les plus importants de l'année écoulée.

Future culprit detection based on angiography-derived FFR.

OBJECTIVES: We sought to characterize the hemodynamic impact of mild coronary artery disease (CAD) using quantitative flow ratio (QFR, an angiography-derived fractional flow reserve [FFR]) in a population of patients with only non-significant CAD at baseline that subsequently experienced a myocardial infarction (MI). BACKGROUND: The discriminatory value of FFR in patients with mild CAD remains imperfect. METHODS: We retrospectively included patients who underwent invasive coronary angiography for an MI, in whom another angiogram had been performed within the previous 5 years. Three-dimensional quantitative coronary angiography, QFR, and lesion length analysis were conducted on lesions responsible for the MI (future culprit lesions, [FCL]) as well as on control lesions (non-culprit lesions, [NCL]). RESULTS: Eighty-three FCL and 117 NCL were analyzed in 83 patients: FCL were more severe (median % diameter of stenosis [DS] 39.1% [29.8; 45.7] vs. 29.8% [25.0; 37.2], p < .001), had lower QFR values (0.94 [0.86; 0.98] vs. 0.98 [0.96; 1.00], p < .001) and tended to be longer (15.2 mm [10.0; 27.3] vs. 12.7 mm [9.3; 22.4], p = .070) than NCL. In lesions with an interval < 2 years between baseline angiography and MI, the difference in QFR was more pronounced compared to the lesions with a longer interval (FCL: 0.92 [0.85; 0.97] vs. NCL: 0.98 [0.94; 1.00], p < .001 and FCL: 0.96 [0.88; 1.00] vs. NCL: 0.98 [0.96;1.00], p = .006 respectively) CONCLUSION: Mild coronary stenoses that are subsequently responsible for an MI (FCL) exhibit a higher DS and lower QFR years before the event. Furthermore, FCL with a lower QFR at baseline appear to lead earlier to MI.

Optimal Timing of Invasive Coronary Angiography following NSTEMI.

OBJECTIVE: To obtain a real-world perspective of the optimal timing of angiography performed within 24 hours of admission with non-ST elevation myocardial infarction (NSTEMI). BACKGROUND: Current guidelines recommend angiography within 24 hours of hospitalisation with NSTEMI. The recent VERDICT trial found that angiography within 12 hours of admission with NSTEMI was associated with improved cardiovascular outcomes among high-risk patients. We compared the outcomes of real-world NSTEMI patients undergoing angiography within 12 hours of admission with those of patients undergoing angiography 12 to 24 hours after admission. METHODS: NSTEMI patients without life-threatening features who received angiography within 24 hours of admission were obtained from the SPUM-ACS registry, a cohort of consecutive patients admitted with acute coronary syndromes to four university hospitals in Switzerland. Cox models assessed for an association between door-to-catheter time and one-year major adverse cardiovascular events (MACE: cardiovascular mortality, myocardial infarction, and stroke). RESULTS: Of 2672 NSTEMI patients, 1832 met the inclusion criteria. Among them, 1464 patients underwent angiography within 12 hours (12 h group) compared with 368 patients between 12 and 24 hours (12-24 h group). Multiple logistic regression identified out-of-hours admission as the only factor associated with delayed angiography. After 2 : 1 propensity score matching, 736 patients from the 12 h group and 368 patients from the 12-24 h group demonstrated no significant difference in rates of one-year MACE (7.7% vs. 7.3%, HR: 1.050, 95% CI 0.637-1.733, p=0.847). Stratification by GRACE score (>140 vs. ≤140) found no significant reduction in MACE among high-risk patients in the 12 h group (p=0.847). Stratification by GRACE score (>140 vs. ≤140) found no significant reduction in MACE among high-risk patients in the 12 h group (. CONCLUSIONS: In an unselected real-world cohort of NSTEMI patients, angiography within 12 hours of admission was not associated with improved one-year cardiovascular outcomes when compared with angiography 12 and 24 hours after admission, even among high-risk patients.

Asymptomatic Aortic Stenosis: From Risk Stratification to Treatment.

Our understanding of the natural history of aortic stenosis has significantly increased over the last decade. There have been considerable advances in the diagnosis and risk stratification of patients with aortic stenosis and in surgical and anesthetic techniques. In addition, transcatheter aortic valve replacement has established itself as a viable alternative to surgical management. Inevitably, these developments have raised questions regarding the merits of waiting for symptom onset in asymptomatic patients with severe aortic stenosis before offering treatment. Recent observational and randomized trial data suggest that early intervention in asymptomatic patients with severe aortic stenosis and normal left ventricular function may confer a prognostic advantage to a watchful waiting strategy. In this review, we highlight advances in the management and risk stratification of patients with asymptomatic severe aortic stenosis with particular consideration of recent findings supporting early valvular intervention.

Advancements and future perspectives in coronary angiography-derived fractional flow reserve.

Angiography-derived fractional flow reserve (FFR) has emerged as a non-invasive technique to assess the functional significance of coronary artery stenoses. The clinical applications of angiography-derived FFR span a wide range of scenarios, including assessing intermediate coronary lesions and guiding revascularization decisions. This review paper aims to provide an overview of angiography-derived FFR, including its principles, clinical applications, and evidence supporting its accuracy and utility. Lastly, the review discusses future directions and ongoing research in the field, including the integration of angiography-derived FFR into routine clinical practice.

AngioPy segmentation: An open-source, user-guided deep learning tool for coronary artery segmentation.

BACKGROUND: Quantitative coronary angiography (QCA) typically employs traditional edge detection algorithms that often require manual correction. This has important implications for the accuracy of downstream 3D coronary reconstructions and computed haemodynamic indices (e.g. angiography-derived fractional flow reserve). We developed AngioPy, a deep-learning model for coronary segmentation that employs user-defined ground-truth points to boost performance and minimise manual correction. We compared its performance without correction with an established QCA system. METHODS: Deep learning models integrating user-defined ground-truth points were developed using 2455 images from the Fractional Flow Reserve versus Angiography for Multivessel Evaluation 2 (FAME 2) study. External validation was performed on a dataset of 580 images. Vessel dimensions from 203 images with mild/moderate stenoses segmented by AngioPy (without correction) and an established QCA system (Medis QFR®) were compared (609 diameters). RESULTS: The top-performing model had an average F1 score of 0.927 (pixel accuracy 0.998, precision 0.925, sensitivity 0.930, specificity 0.999) with 99.2 % of masks exhibiting an F1 score > 0.8. Similar results were seen with external validation (F1 score 0.924, pixel accuracy 0.997, precision 0.921, sensitivity 0.929, specificity 0.999). Vessel dimensions from AngioPy exhibited excellent agreement with QCA (r = 0.96 [95 % CI 0.95-0.96], p < 0.001; mean difference - 0.18 mm [limits of agreement (LOA): -0.84 to 0.49]), including the minimal luminal diameter (r = 0.93 [95 % CI 0.91-0.95], p < 0.001; mean difference - 0.06 mm [LOA: -0.70 to 0.59]). CONCLUSION: AngioPy, an open-source tool, performs rapid and accurate coronary segmentation without the need for manual correction. It has the potential to increase the accuracy and efficiency of QCA.

The Influence of Epicardial Resistance on Microvascular Resistance Reserve.

BACKGROUND: The optimal index of microvascular function should be specific for the microvascular compartment. Yet, coronary flow reserve (CFR), despite being widely used to diagnose coronary microvascular dysfunction (CMD), is influenced by both epicardial and microvascular resistance. Conversely, microvascular resistance reserve (MRR) adjusts for fractional flow reserve (FFR), and thus is theoretically independent of epicardial resistance. OBJECTIVES: The authors tested the hypothesis that MRR, unlike CFR, is not influenced by increasing epicardial resistance, and thus is a more specific index of microvascular function. METHODS: In a cohort of 16 patients who had undergone proximal left anterior descending artery stenting, we created 4 grades of artificial stenosis (no stenosis, mild, moderate, and severe) using a coronary angioplasty balloon inflated to different degrees within the stent. For each stenosis grade, we calculated CFR and MRR using continuous thermodilution (64 measurements of each) to assess their response to changing epicardial resistance. RESULTS: Graded balloon inflation resulted in a significant sequential decrease in mean FFR (no stenosis: 0.82 ± 0.05; mild: 0.72 ± 0.04; moderate: 0.61 ± 0.05; severe: 0.48 ± 0.09; P < 0.001). This translated into a linear decrease in mean hyperemic coronary flow (no stenosis: 170.5 ± 66.8 mL/min; mild: 149.8 ± 58.8 mL/min; moderate: 124.4 ± 53.0 mL/min; severe: 94.0 ± 45.2 mL/min; P < 0.001). CFR exhibited a marked linear decrease with increasing stenosis (no stenosis: 2.5 ± 0.9; mild: 2.2 ± 0.8; moderate: 1.8 ± 0.7; severe: 1.4 ± 0.6), corresponding to a decrease of 0.3 for a decrease in FFR of 0.1 (P < 0.001). In contrast, MRR exhibited a negligible decrease across all stenosis grades (no stenosis: 3.0 ± 1.0; mild: 3.0 ± 1.0; moderate: 2.9 ± 1.0; severe: 2.8 ± 1.0), corresponding to a decrease of just 0.05 for a decrease in FFR of 0.1 (P < 0.001). CONCLUSIONS: MRR, unlike CFR, is minimally influenced by epicardial resistance, and thus should be considered the more specific index of microvascular function. This suggests that MRR can also reliably evaluate microvascular function in patients with significant epicardial disease.

Head-to-head comparison of two angiography-derived fractional flow reserve techniques in patients with high-risk acute coronary syndrome: A multicenter prospective study.

BACKGROUND: FFRangio and QFR are angiography-based technologies that have been validated in patients with stable coronary artery disease. No head-to-head comparison to invasive fractional flow reserve (FFR) has been reported to date in patients with acute coronary syndromes (ACS). METHODS: This study is a subset of a larger prospective multicenter, single-arm study that involved patients diagnosed with high-risk ACS in whom 30-70% stenosis was evaluated by FFR. FFRangio and QFR - both calculated offline by 2 different and blinded operators - were calculated and compared to FFR. The two co-primary endpoints were the comparison of the Pearson correlation coefficient between FFRangio and QFR with FFR and the comparison of their inter-observer variability. RESULTS: Among 134 high-risk ACS screened patients, 59 patients with 84 vessels underwent FFR measurements and were included in this study. The mean FFR value was 0.82 ± 0.40 with 32 (38%) being ≤0.80. The mean FFRangio was 0.82 ± 0.20 and the mean QFR was 0.82 ± 0.30, with 27 (32%) and 25 (29%) being ≤0.80, respectively. The Pearson correlation coefficient was significantly better for FFRangio compared to QFR, with R values of 0.76 and 0.61, respectively (p = 0.01). The inter-observer agreement was also significantly better for FFRangio compared to QFR (0.86 vs 0.79, p < 0.05). FFRangio had 91% sensitivity, 100% specificity, and 96.8% accuracy, while QFR exhibited 86.4% sensitivity, 98.4% specificity, and 93.7% accuracy. CONCLUSION: In patients with high-risk ACS, FFRangio and QFR demonstrated excellent diagnostic performance. FFRangio seems to have better correlation to invasive FFR compared to QFR but further larger validation studies are required.

Assessing the Impact of Prolonged Averaging of Coronary Continuous Thermodilution Traces.

Continuous Thermodilution is a novel method of quantifying coronary flow (Q) in mL/min. To account for variability of Q within the cardiac cycle, the trace is smoothened with a 2 s moving average filter. This can sometimes be ineffective due to significant heart rate variability, ventricular extrasystoles, and deep inspiration, resulting in a fluctuating temperature trace and ambiguity in the location of the "steady state". This study aims to assess whether a longer moving average filter would smoothen any fluctuations within the continuous thermodilution traces resulting in improved interpretability and reproducibility on a test-retest basis. Patients with ANOCA underwent repeat continuous thermodilution measurements. Analysis of traces were performed at averages of 10, 15, and 20 s to determine the maximum acceptable average. The maximum acceptable average was subsequently applied as a moving average filter and the traces were re-analysed to assess the practical consequences of a longer moving average. Reproducibility was then assessed and compared to a 2 s moving average. Of the averages tested, only 10 s met the criteria for acceptance. When the data was reanalysed with a 10 s moving average filter, there was no significant improvement in reproducibility, however, it resulted in a 12% diagnostic mismatch. Applying a longer moving average filter to continuous thermodilution data does not improve reproducibility. Furthermore, it results in a loss of fidelity on the traces, and a 12% diagnostic mismatch. Overall, current practice should be maintained.

Measuring Absolute Coronary Flow and Microvascular Resistance by Thermodilution: JACC Review Topic of the Week.

Diagnosing coronary microvascular dysfunction remains challenging, primarily due to the lack of direct measurements of absolute coronary blood flow (Q) and microvascular resistance (Rµ). However, there has been recent progress with the development and validation of continuous intracoronary thermodilution, which offers a simplified and validated approach for clinical use. This technique enables direct quantification of Q and Rµ, leading to precise and accurate evaluation of the coronary microcirculation. To ensure consistent and reliable results, it is crucial to follow a standardized protocol when performing continuous intracoronary thermodilution measurements. This document aims to summarize the principles of thermodilution-derived absolute coronary flow measurements and propose a standardized method for conducting these assessments. The proposed standardization serves as a guide to ensure the best practice of the method, enhancing the clinical assessment of the coronary microcirculation.

Simplification of continuous intracoronary thermodilution.

BACKGROUND: Continuous intracoronary thermodilution with saline allows for the accurate measurement of volumetric blood flow (Q) and absolute microvascular resistance (Rµ). However, this requires repositioning of the temperature sensor by the operator to measure the entry temperature of the saline infusate, denoted as Ti. AIMS: We evaluated whether Ti could be predicted based on known parameters without compromising the accuracy of calculated Q. This would significantly simplify the technique and render it completely operator independent. METHODS: In a derivation cohort of 371 patients with Q measured both at rest and during hyperaemia, multivariate linear regression was used to derive an equation for the prediction of Ti. Agreement between standard Q (calculated with measured Ti) and simplified Q (calculated with predicted Ti) was assessed in a validation cohort of 120 patients that underwent repeat Q measurements. The accuracy of simplified Q was assessed in a second validation cohort of 23 patients with [15O]H2O positron emission tomography (PET)-derived Q measurements. RESULTS: Simplified Q exhibited strong agreement with standard Q (r=0.94, confidence interval [CI]: 0.93-0.95; intraclass correlation coefficient [ICC] 0.94, CI: 0.92-0.95; both p<0.001). Simplified Q exhibited excellent agreement with PET-derived Q (r=0.86, CI: 0.75-0.92; ICC=0.84, CI: 0.72-0.91; both p<0.001). Compared with standard Q, there were no statistically significant differences between correlation coefficients (p=0.29) or standard deviations of absolute differences with PET-derived Q (p=0.85). CONCLUSIONS: Predicting Ti resulted in an excellent agreement with measured Ti for the assessment of coronary blood flow. It significantly simplifies continuous intracoronary thermodilution and renders absolute coronary flow measurements completely operator independent.

ChatGPT takes on the European Exam in Core Cardiology: an artificial intelligence success story?

Chat Generative Pre-trained Transformer (ChatGPT) is currently a trending topic worldwide triggering extensive debate about its predictive power, its potential uses, and its wider implications. Recent publications have demonstrated that ChatGPT can correctly answer questions from undergraduate exams such as the United States Medical Licensing Examination. We challenged it to answer questions from a more demanding, post-graduate exam-the European Exam in Core Cardiology (EECC), the final exam for the completion of specialty training in Cardiology in many countries. Our results demonstrate that ChatGPT succeeds in the EECC.