Comparison of clinical interpretation with visual assessment and quantitative coronary angiography in patients undergoing percutaneous coronary intervention in contemporary practice: the Assessing Angiography (A2) project

Prospective investigation of calcium score in optical coherence tomography-guided revascularization to identify lesions with low risk for stent under expansion: the CORAL study

The optical coherence tomography (OCT)-based calcium scoring system was developed to guide optimal lesion preparation strategies for percutaneous coronary intervention (PCI) of calcified lesions. However, the score was derived retrospectively, and a prospective investigation is lacking. The CORAL (UMIN000053266) study was a single-arm, prospective, multicenter study that included patients with calcified lesions with OCT-calcium score of 1-2 to investigate whether these lesions could be optimally treated with a balloon-only preparation strategy using a non-compliant/scoring/cutting balloon. The primary endpoint was strategy success (successful stent placement with a final percent diameter stenosis [%DS] < 20% and Thrombolysis In Myocardial Infarction flow grade III without crossover to rotational atherectomy/orbital atherectomy/intravascular lithotripsy [RA/OA/IVL]). A superiority analysis for the primary endpoint was performed by comparing the study cohort with a performance goal of 83.3%. One hundred and eighteen patients with 130 lesions were enrolled. The mean age was 79.0 ± 10.3 years, and 79 patients (66.9%) were male. The OCT-calcium score was 1 for 81 lesions (62.3%) and 2 for 49 lesions (37.7%). The %DS improved from 47.0 ± 14.8% preprocedure to 11.1 ± 5.6% postprocedure. Stent expansion ≥ 70% was achieved in 90.2%. The strategy success rate was 93.1% (95% confidence interval: 87.3-96.8), and superiority against the performance goal was achieved without any crossover to RA/OA/IVL (P = 0.0027). The OCT-calcium score could identify mild/moderately calcified lesions treatable by PCI with the balloon-first strategy using a non-compliant/scoring/cutting balloon for predilatation, with a high strategy success rate. These results support the intravascular imaging-based treatment algorithm for calcified lesions proposed by CVIT.

Evaluation of stenoses using AI video models applied to coronary angiography

The coronary angiogram is the gold standard for evaluating the severity of coronary artery disease stenoses. Presently, the assessment is conducted visually by cardiologists, a method that lacks standardization. This study introduces DeepCoro, a ground-breaking AI-driven pipeline that integrates advanced vessel tracking and a video-based Swin3D model that was trained and validated on a dataset comprised of 182,418 coronary angiography videos spanning 5 years. DeepCoro achieved a notable precision of 71.89% in identifying coronary artery segments and demonstrated a mean absolute error of 20.15% (95% CI: 19.88-20.40) and a classification AUROC of 0.8294 (95% CI: 0.8215-0.8373) in stenosis percentage prediction compared to traditional cardiologist assessments. When compared to two expert interventional cardiologists, DeepCoro achieved lower variability than the clinical reports (19.09%; 95% CI: 18.55-19.58 vs 21.00%; 95% CI: 20.20-21.76, respectively). In addition, DeepCoro can be fine-tuned to a different modality type. When fine-tuned on quantitative coronary angiography assessments, DeepCoro attained an even lower mean absolute error of 7.75% (95% CI: 7.37-8.07), underscoring the reduced variability inherent to this method. This study establishes DeepCoro as an innovative video-based, adaptable tool in coronary artery disease analysis, significantly enhancing the precision and reliability of stenosis assessment.

Quantitative Angiography: The Dawn of a New Era in Cardiovascular Medicine

This comprehensive review explores the transformative role of quantitative angiography in the landscape of cardiovascular medicine. Tracing the historical evolution of cardiovascular diagnostics, we emphasize the significance of angiography in diagnosis and treatment. The primary focus on quantitative angiography reveals its capacity to move beyond qualitative assessments, providing clinicians with precise measurements and objective parameters. This paradigm shift enhances diagnostic accuracy, promising far-reaching implications for the future of cardiovascular medicine. The ability to tailor interventions based on meticulous measurements optimizes therapeutic strategies and positions the field on the brink of a new era where personalized approaches become the norm. However, challenges such as image quality, radiation exposure, and interpretation variability persist, necessitating a collective call to action for continued research and development. As we confront these issues, collaborative efforts across disciplines are essential to refine existing technologies and usher in innovative solutions. This review concludes with a resounding call for ongoing research initiatives, large-scale clinical studies, and collective commitment to propel quantitative angiography into a universally accepted standard, ensuring its full realization in enhancing patient care and outcomes in cardiovascular medicine.

Feasibility and Diagnostic Performance of Functional SYNTAX Score Derived From Dynamic CT Myocardial Perfusion Imaging

BACKGROUND

Computed tomography (CT) fractional flow reserve (FFR)-derived functional SYNTAX score (FSSCT-FFR) is a valuable method for guiding treatment strategy in patients with multivessel coronary artery disease. Dynamic CT myocardial perfusion imaging (CT-MPI) demonstrates higher diagnostic accuracy than CT-FFR in identifying hemodynamically significant coronary artery disease. We aimed to evaluate the feasibility of CT-MPI-derived FSS (FSSCT-MPI) with reference to invasive FSS.

METHODS

In this retrospective study, patients with multivessel coronary artery disease who underwent dynamic CT-MPI+ coronary CT angiography and invasive coronary angiography or FFR within 4 weeks were consecutively included. Invasive (FSSinvasive) and noninvasive FSS (FSSCT-MPI and FSSCT-FFR) were calculated by an online calculator, which assigned points to lesions with hemodynamic significance (defined as FFRinvasive ≤0.80, invasive coronary angiography diameter stenosis ≥90%, CT-FFR ≤0.80, and myocardial ischemia on CT-MPI). Weighted κ value and net reclassification index were calculated to determine the consistency and incremental discriminatory power of FSSCT-MPI. Receiver operating characteristic curve analysis was used for the comparison of FSSCT-MPI and FSSCT-FFR in detecting intermediate- to high-risk patients.

RESULTS

A total of 119 patients (96 men; 64.6±10.6 years) with 305 obstructive lesions were included. The average FSSCT-MPI, FSSCT-FFR, and FSSinvasive were 15.58±13.03, 16.18±13.30, and 13.11±12.22, respectively. The agreement on risk classification based on the FSSCT-MPI tertiles was good (weighted κ, 0.808). With reference to FSSinvasive, FSSCT-MPI correctly reclassified 27 (22.7%) patients from the intermediate- to high SYNTAX score group to the low-score group (net reclassification index, 0.30; P<0.001). In patients with severe calcification, FSSCT-MPI had better diagnostic value than FSSCT-FFR in detecting intermediate- to high-risk patients when compared with FSSinvasive (area under the curve, 0.976 versus 0.884; P<0.001).

CONCLUSIONS

Noninvasive FSS derived from CT-MPI is feasible and has strong concordance with FSSinvasive. It allows accurate categorization of FSS in patients with multivessel coronary artery disease, in particular with severe calcification.

Clinical quantitative coronary artery stenosis and coronary atherosclerosis imaging: a Consensus Statement from the Quantitative Cardiovascular Imaging Study Group

The detection and characterization of coronary artery stenosis and atherosclerosis using imaging tools are key for clinical decision-making in patients with known or suspected coronary artery disease. In this regard, imaging-based quantification can be improved by choosing the most appropriate imaging modality for diagnosis, treatment and procedural planning. In this Consensus Statement, we provide clinical consensus recommendations on the optimal use of different imaging techniques in various patient populations and describe the advances in imaging technology. Clinical consensus recommendations on the appropriateness of each imaging technique for direct coronary artery visualization were derived through a three-step, real-time Delphi process that took place before, during and after the Second International Quantitative Cardiovascular Imaging Meeting in September 2022. According to the Delphi survey answers, CT is the method of choice to rule out obstructive stenosis in patients with an intermediate pre-test probability of coronary artery disease and enables quantitative assessment of coronary plaque with respect to dimensions, composition, location and related risk of future cardiovascular events, whereas MRI facilitates the visualization of coronary plaque and can be used in experienced centres as a radiation-free, second-line option for non-invasive coronary angiography. PET has the greatest potential for quantifying inflammation in coronary plaque but SPECT currently has a limited role in clinical coronary artery stenosis and atherosclerosis imaging. Invasive coronary angiography is the reference standard for stenosis assessment but cannot characterize coronary plaques. Finally, intravascular ultrasonography and optical coherence tomography are the most important invasive imaging modalities for the identification of plaques at high risk of rupture. The recommendations made in this Consensus Statement will help clinicians to choose the most appropriate imaging modality on the basis of the specific clinical scenario, individual patient characteristics and the availability of each imaging modality.

Segmentation of X-ray coronary angiography with an artificial intelligence deep learning model: Impact in operator visual assessment of coronary stenosis severity

BACKGROUND

Visual assessment of the percentage diameter stenosis (%DSVE ) of lesions is essential in coronary angiography (CAG) interpretation. We have previously developed an artificial intelligence (AI) model capable of accurate CAG segmentation. We aim to compare operators' %DSVE in angiography versus AI-segmented images.

METHODS

Quantitative coronary analysis (QCA) %DS (%DSQCA ) was previously performed in our published validation dataset. Operators were asked to estimate %DSVE of lesions in angiography versus AI-segmented images in separate sessions and differences were assessed using angiography %DSQCA as reference.

RESULTS

A total of 123 lesions were included. %DSVE was significantly higher in both the angiography (77% ± 20% vs. 56% ± 13%, p < 0.001) and segmentation groups (59% ± 20% vs. 56% ± 13%, p < 0.001), with a much smaller absolute %DS difference in the latter. For lesions with %DSQCA of 50%-70% (60% ± 5%), an even higher discrepancy was found (angiography: 83% ± 13% vs. 60% ± 5%, p < 0.001; segmentation: 63% ± 15% vs. 60% ± 5%, p < 0.001). Similar, less pronounced, findings were observed for %DSQCA  < 50% lesions, but not %DSQCA  > 70% lesions. Agreement between %DSQCA /%DSVE across %DSQCA strata (<50%, 50%-70%, >70%) was approximately twice in the segmentation group (60.4% vs. 30.1%; p < 0.001). %DSVE inter-operator differences were smaller with segmentation.

CONCLUSION

%DSVE was much less discrepant with segmentation versus angiography. Overestimation of %DSQCA  < 70% lesions with angiography was especially common. Segmentation may reduce %DSVE overestimation and thus unwarranted revascularization.

CathAI: fully automated coronary angiography interpretation and stenosis estimation

Coronary angiography is the primary procedure for diagnosis and management decisions in coronary artery disease (CAD), but ad-hoc visual assessment of angiograms has high variability. Here we report a fully automated approach to interpret angiographic coronary artery stenosis from standard coronary angiograms. Using 13,843 angiographic studies from 11,972 adult patients at University of California, San Francisco (UCSF), between April 1, 2008 and December 31, 2019, we train neural networks to accomplish four sequential necessary tasks for automatic coronary artery stenosis localization and estimation. Algorithms are internally validated against criterion-standard labels for each task in hold-out test datasets. Algorithms are then externally validated in real-world angiograms from the University of Ottawa Heart Institute (UOHI) and also retrained using quantitative coronary angiography (QCA) data from the Montreal Heart Institute (MHI) core lab. The CathAI system achieves state-of-the-art performance across all tasks on unselected, real-world angiograms. Positive predictive value, sensitivity and F1 score are all ≥90% to identify projection angle and ≥93% for left/right coronary artery angiogram detection. To predict obstructive CAD stenosis (≥70%), CathAI exhibits an AUC of 0.862 (95% CI: 0.843-0.880). In UOHI external validation, CathAI achieves AUC 0.869 (95% CI: 0.830-0.907) to predict obstructive CAD. In the MHI QCA dataset, CathAI achieves an AUC of 0.775 (95%. CI: 0.594-0.955) after retraining. In conclusion, multiple purpose-built neural networks can function in sequence to accomplish automated analysis of real-world angiograms, which could increase standardization and reproducibility in angiographic coronary stenosis assessment.

MINOCA and INOCA: Role in Heart Failure

PURPOSE OF REVIEW

Infarction (MINOCA) and ischaemia (INOCA) with non-obstructive coronary disease are recent non-conventional presentations of coronary syndromes that are increasingly recognised in the clinical arena, particularly with the availability of new cardiovascular imaging techniques. Both are related to heart failure (HF). MINOCA is not associated with benign outcomes, and HF is among the most prevalent events. Regarding INOCA, microvascular dysfunction has also been found to associate with HF, particularly with preserved ejection fraction (HFpEF).

RECENT FINDINGS

Regardless of the several aetiologies underlying HF in MINOCA, it is likely related to LV dysfunction, where secondary prevention is not yet clearly established. Regarding INOCA, coronary microvascular ischaemia has been associated to endothelial dysfunction leading ultimately to diastolic dysfunction and HFpEF. MINOCA and INOCA are clearly related to HF. In both, there is a lack of studies on the identification of the risk factors for HF, diagnostic workup and, importantly, the appropriate primary and secondary prevention strategies.

Coronary X-ray angiography segmentation using Artificial Intelligence: a multicentric validation study of a deep learning model

INTRODUCTION

We previously developed an artificial intelligence (AI) model for automatic coronary angiography (CAG) segmentation, using deep learning. To validate this approach, the model was applied to a new dataset and results are reported.

METHODS

Retrospective selection of patients undergoing CAG and percutaneous coronary intervention or invasive physiology assessment over a one month period from four centers. A single frame was selected from images containing a lesion with a 50-99% stenosis (visual estimation). Automatic Quantitative Coronary Analysis (QCA) was performed with a validated software. Images were then segmented by the AI model. Lesion diameters, area overlap [based on true positive (TP) and true negative (TN) pixels] and a global segmentation score (GSS - 0 -100 points) - previously developed and published - were measured.

RESULTS

123 regions of interest from 117 images across 90 patients were included. There were no significant differences between lesion diameter, percentage diameter stenosis and distal border diameter between the original/segmented images. There was a statistically significant albeit minor difference [0,19 mm (0,09-0,28)] regarding proximal border diameter. Overlap accuracy ((TP + TN)/(TP + TN + FP + FN)), sensitivity (TP / (TP + FN)) and Dice Score (2TP / (2TP + FN + FP)) between original/segmented images was 99,9%, 95,1% and 94,8%, respectively. The GSS was 92 (87-96), similar to the previously obtained value in the training dataset.

CONCLUSION

the AI model was capable of accurate CAG segmentation across multiple performance metrics, when applied to a multicentric validation dataset. This paves the way for future research on its clinical uses.

Procedural Characteristics of Intravascular Ultrasound–Guided Percutaneous Coronary Intervention and Their Clinical Implications

Background

Despite the clinical benefits to intravascular ultrasound (IVUS) guidance for percutaneous coronary intervention (PCI), most patients with coronary artery disease undergo angiography‐guided PCI alone in the real‐world setting. We sought to investigate the procedural characteristics of IVUS‐guided PCI and their clinical outcomes, as compared with angiography‐guided PCI.

Methods and Results

This was a cohort study using patient‐level data from the IVUS‐XPL (Impact of Intravascular Ultrasound Guidance on the Outcomes of Xience Prime Stents in Long Lesions) and ULTIMATE (Intravascular Ultrasound Guided Drug Eluting Stents Implantation in All‐Comers Coronary Lesions) clinical trials. A total of 2848 patients with 3872 native coronary lesions were included and procedural characteristics assessed by quantitative coronary angiography (QCA) were compared between IVUS and angiography guidance. Stent‐to‐reference vessel diameter ratio (ie, QCA stent sizing) was greater (1.11±0.16 versus 1.07±0.14, P <0.001) and high‐pressure postdilation was more frequently performed (83.7% versus 75.4%, P <0.001) with IVUS guidance, whereas residual stent edge dissections were more frequent in lesions treated with IVUS guidance (4.6% versus 0.7%, P <0.001). Given the dissection risk, optimal QCA stent sizing for IVUS guidance was a stent‐to‐QCA reference vessel diameter ratio ≥1.1 to <1.3. Among 1424 patients (1969 lesions) treated with angiography guidance, QCA stent sizing <1.0 was observed in 651 (33.1%) lesions, while QCA stent sizing ≥1.1 to <1.3 was observed in only 526 (26.7%) lesions. Under angiography guidance, patients with both QCA stent sizing ≥1.1 to <1.3 and high‐pressure postdilation (235 of 1424, 16.5%) had a lower risk of 3‐year target lesion failure compared with others (hazard ratio, 0.532; 95% CI, 0.293–0.966 [ P =0.038]).

Conclusions

IVUS‐guided PCI resulted in larger QCA‐assessed stent sizing and more frequent postdilation with high‐pressure inflations. These procedures may further improve long‐term clinical outcomes in patients undergoing PCI without IVUS.

Registration

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01308281 (IVUS‐XPL); NCT02215915 (ULTIMATE).

Clinical Evaluation of the Automatic Coronary Artery Disease Reporting and Data System (CAD-RADS) in Coronary Computed Tomography Angiography Using Convolutional Neural Networks

RATIONALE AND OBJECTIVES

The coronary artery disease reporting and data system (CAD-RADS™) was recently introduced to standardise reporting. We aimed to evaluate the utility of an automatic postprocessing and reporting system based on CAD-RADS™ in suspected coronary artery disease (CAD) patients.

MATERIALS AND METHODS

Clinical evaluation was performed in 346 patients who underwent coronary computed tomography angiography (CCTA). We compared deep learning (DL)-based CCTA with human readers for evaluation of CAD-RADS™ with commercially-available automated segmentation and manual postprocessing in a retrospective validation cohort.

RESULTS

Compared with invasive coronary angiography, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the DL model for diagnosis of CAD were 79.02%, 86.52%, 89.50%, 73.94%, and 82.08%, respectively. There was no significant difference between the DL-based and the reader-based CAD-RADS™ grading of CCTA results. Consistency testing showed that the Kappa value between the model and the readers was 0.775 (95% confidence interval [CI]: 0.728-0.823, p < 0.001), 0.802 (95% CI: 0.756-0.847, p < 0.001), and 0.796 (95% CI: 0.750-0.843, p < 0.001), respectively. This system reduces the time taken from 14.97 ± 1.80 min to 5.02 ± 0.8 min (p < 0.001).

CONCLUSION

The standardised reporting of DL-based CAD-RADS™ in CCTA can accurately and rapidly evaluate suspected CAD patients, and has good consistency with grading by radiologists.

A Newly Defined CHA2DS2-VA Score for Predicting Obstructive Coronary Artery Disease in Patients with Atrial Fibrillation-A Cross-Sectional Study of Older Persons Referred for Elective Coronary Angiography

Purpose: Atrial fibrillation (AF) can be a valuable indicator of non-obstructive coronary artery disease (CAD) among older patients indicated for elective coronary angiography (CAG). Appropriate stratification of AF patients is crucial for avoiding unnecessary complications. The objective of this study was to identify independent predictors that can allow diagnosing obstructive CAD in AF patients over 65 years who were indicated to undergo elective CAG. Patients and methods: This cross-sectional study included 452 (23.9%) AF patients over 65 years old who were directed to the Department of Invasive Cardiology at the Medical University of Bialystok for elective CAG during 2014−2016. The participants had CAD and were receiving optimal therapy (median age: 73 years, interquartile range: 69−77 years; 54.6% men). The prevalence and health correlates of obstructive CAD were determined, and a multivariate logistic regression model was generated with predictors (p < 0.1). Predictive performance was analyzed using a receiver-operating characteristic (ROC) curve analysis. Results: Stenosis (affecting ≥ 50% of the diameter of the left coronary artery stem or ≥70% of that of the other important epicardial vessels) was significant in 184 (40.7%) cases. Multivariate regression analysis revealed that only the male sex (odds ratio [OR]: 1.80, 95% confidence interval [CI]: 1.14−2.84, p = 0.01) and the newly created CHA2DS2-VA score (OR: 3.96, 95% CI: 2.96−5.31, p < 0.001) significantly increased the chance of obstructive CAD, while controlling for chronic kidney disease and anemia. The ROC curve analysis indicated that the CHA2DS2-VA scale may be a useful screening tool for the diagnosis of obstructive CAD (area under the ROC curve: 0.79, 95% CI: 0.75−0.84, p < 0.001), with ≥4 being the optimal cutoff value. Conclusions: Our study has proven that several older AF patients who are advised to undergo elective CAG have nonobstructive CAD. The CHA2DS2-VA score can contribute to improving the selection of patients for invasive diagnosis of CAD, but further investigation is required.

The use of lesion-specific calcium morphology to guide the appropriate use of dynamic CT myocardial perfusion imaging and CT fractional flow reserve

Background

We aimed to optimize the diagnostic strategy for dynamic computed tomography myocardial perfusion imaging (CT-MPI) and CT fractional flow reserve (CT-FFR) in the evaluation of coronary artery disease (CAD).

Methods

Patients who had undergone coronary CT angiography (CCTA) + dynamic CT-MPI and invasive coronary angiography (ICA)/FFR within a 4-week period were retrospectively included. Lesion-specific characteristics were recorded, and multivariate logistic regression was performed to determine the predictors of mismatched CT findings with ICA results. An optimized diagnostic strategy was proposed based on the diagnostic performance of dynamic CT-MPI and CT-FFR compared with ICA/FFR. A net reclassification index (NRI) was calculated to determine the incremental discriminatory power of optimized CT-FFR + dynamic CT-MPI strategy compared to CT-FFR alone.

Results

The study included 180 patients with 229 diseased vessels. For CT-FFR, a calcified lesion with a calcium arc >180° was the only independent predictor for misdiagnosis of ischemic coronary stenosis (odds ratio =2.367; P=0.002). For noncalcified lesions and calcified lesions with a calcium arc ≤180°, the sensitivity and negative predictive value (NPV) of CT-FFR were similar to those of CT-MPI (all P values >0.05), whereas the specificity and positive predictive value (PPV) of CT-FFR were significantly lower (all P values <0.05). For calcified lesions with a calcium arc >180°, the specificity, NPV, and PPV of CT-FFR were inferior to those of CT-MPI (21.2% vs. 100%, 58.3% vs. 86.8%, and 62.9% vs. 100%, respectively; all P values <0.05). As guided by lesion-specific calcium morphology, an optimized CT-FFR + dynamic CT-MPI strategy (NRI =0.2; P=0.004) would have resulted in a 27.0% and 33.9% reduction of radiation dose and contrast medium consumption, respectively, and 25.3% of patients would have avoided unnecessary invasive tests.

Conclusions

The diagnostic performance of CT-FFR was significantly inferior in lesions with a calcium arc >180°. Lesion-specific calcium morphology is the preferred parameter to guide the appropriate use of CT-based functional assessment.

Atrial fibrillation is a predictor of nonobstructive coronary artery disease in elective angiography in old age: a cross-sectional study in Poland and Russia

BACKGROUND

Significant changes in the coronary vessels are not confirmed in a large proportion of patients undergoing cardiac catheterization.

AIMS

The present study aimed to determine correlates and independent predictors of nonobstructive coronary artery disease (CAD) in older adults referred for elective coronary angiography.

METHODS

A cross-sectional study was conducted involving 2,214 patients referred to two medical centers (in Poland and Russia) between 2014 and 2016 for elective coronary angiography due to exacerbated angina, despite undergoing optimal therapy for CAD. The median age was 72 years (IQR: 68-76), and 49.5% patients were women.

RESULTS

Significant stenosis (defined as stenosis of 50% or more of the diameter of the left main coronary artery stem or stenosis of 70% or more of the diameter of the remaining major epicardial vessels) was diagnosed only in 1135 (51.3%) patients. Female sex (odds ratio [OR], 3.01; 95% confidence interval [CI], 2.44-3.72; p < 0.001) and atrial fibrillation (OR, 1.87; 95% CI 1.45-2.40; p < 0.001) were the main independent predictors of nonobstructive CAD. Significantly lower ORs were observed for diabetes (OR, 0.75; 95% CI 0.59-0.95; p = 0.02), chronic kidney disease (OR, 0.76; 95% CI 0.61-0.96; p = 0.02), and anemia (OR, 0.69; 95% CI 0.50-0.95; p = 0.02) after controlling for age, chronic heart failure, BMI, and study center.

DISCUSSION AND CONCLUSIONS

The results confirmed that nonobstructive CAD occurs in a high percentage of older patients referred for elective coronary angiography. This suggests the need to improve patient stratification for invasive diagnosis of CAD, especially for older women and patients with atrial fibrillation. Trial registration number and date of registration: NCT04537507, September 3, 2020.

Implementing Machine Learning in Interventional Cardiology: The Benefits Are Worth the Trouble

Driven by recent innovations and technological progress, the increasing quality and amount of biomedical data coupled with the advances in computing power allowed for much progress in artificial intelligence (AI) approaches for health and biomedical research. In interventional cardiology, the hope is for AI to provide automated analysis and deeper interpretation of data from electrocardiography, computed tomography, magnetic resonance imaging, and electronic health records, among others. Furthermore, high-performance predictive models supporting decision-making hold the potential to improve safety, diagnostic and prognostic prediction in patients undergoing interventional cardiology procedures. These applications include robotic-assisted percutaneous coronary intervention procedures and automatic assessment of coronary stenosis during diagnostic coronary angiograms. Machine learning (ML) has been used in these innovations that have improved the field of interventional cardiology, and more recently, deep Learning (DL) has emerged as one of the most successful branches of ML in many applications. It remains to be seen if DL approaches will have a major impact on current and future practice. DL-based predictive systems also have several limitations, including lack of interpretability and lack of generalizability due to cohort heterogeneity and low sample sizes. There are also challenges for the clinical implementation of these systems, such as ethical limits and data privacy. This review is intended to bring the attention of health practitioners and interventional cardiologists to the broad and helpful applications of ML and DL algorithms to date in the field. Their implementation challenges in daily practice and future applications in the field of interventional cardiology are also discussed.

2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The guideline for coronary artery revascularization replaces the 2011 coronary artery bypass graft surgery and the 2011 and 2015 percutaneous coronary intervention guidelines, providing a patient-centric approach to guide clinicians in the treatment of patients with significant coronary artery disease undergoing coronary revascularization as well as the supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from May 2019 to September 2019, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, CINHL Complete, and other relevant databases. Additional relevant studies, published through May 2021, were also considered. Structure: Coronary artery disease remains a leading cause of morbidity and mortality globally. Coronary revascularization is an important therapeutic option when managing patients with coronary artery disease. The 2021 coronary artery revascularization guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with coronary artery disease who are being considered for coronary revascularization, with the intent to improve quality of care and align with patients' interests.

2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The guideline for coronary artery revascularization replaces the 2011 coronary artery bypass graft surgery and the 2011 and 2015 percutaneous coronary intervention guidelines, providing a patient-centric approach to guide clinicians in the treatment of patients with significant coronary artery disease undergoing coronary revascularization as well as the supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from May 2019 to September 2019, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, CINHL Complete, and other relevant databases. Additional relevant studies, published through May 2021, were also considered.

STRUCTURE

Coronary artery disease remains a leading cause of morbidity and mortality globally. Coronary revascularization is an important therapeutic option when managing patients with coronary artery disease. The 2021 coronary artery revascularization guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with coronary artery disease who are being considered for coronary revascularization, with the intent to improve quality of care and align with patients' interests.

Sex differences in assessing stenosis severity between physician visual assessment and quantitative coronary angiography

BACKGROUND

Physician visual assessment (PVA) in invasive coronary angiography (ICA) is the current clinical method to determine stenosis severity and guide percutaneous coronary intervention. This study sought to evaluate the effect of sex differences in assessing coronary stenosis severity between PVA and quantitative coronary angiography (QCA).

METHODS

209 patients with coronary artery disease (288 coronary lesions) underwent ICA and fractional flow reserve (FFR). ICA image processing including PVA and QCA was used to quantify diameter stenosis (DS). The difference of DS (ΔDS) between PVA and QCA was defined as DS_PVA-DS_QCA. DS ≥50% was considered anatomically obstructive. FFR ≤0.8 was defined as myocardial ischemia.

RESULTS

Mean ± SD age was 63 ± 9 years. There were no significant differences in DS_PVA (61.1 ± 16.3% vs 60.1 ± 18.9%) and DS_QCA (53.1 ± 12.1% vs 55.4 ± 14.3%) between females and males. However, ΔDS between PVA and QCA was higher in females (8.0 ± 10.9%) than in males (4.7 ± 10.9%) (P = 0.03). Thirty-four of 72 vessels (47.2%) in female patients and 75 of 216 vessels (34.7%) in male patients were classified differently by at least one grade using PVA compared to QCA assessment. DS_PVA and DS_QCA were negatively correlated with FFR in females (r_PVA = -0.397, r_QCA = -0.448) with an even stronger negative correlation in males (r_PVA = -0.607, r_QCA = -0.607). ROC analysis demonstrated that DS_QCA had better discrimination capability for myocardial ischemia (FFR ≤ 0.80) than DS_PVA in both sexes (P < 0.05).

CONCLUSIONS

A systematic bias was found in PVA (QCA reference) for overestimating severity of coronary artery disease in females compared to males.

Long-term outcome of patients with NSTEMI and nonobstructive coronary arteries by different angiographic subtypes

INTRODUCTION AND OBJECTIVES

Discordant data have been reported on the prognosis of myocardial infarction with nonobstructive coronary arteries (MINOCA). Moreover, few data are available on the impact of angiographic subtypes. The objectives of this study were to assess the prognostic impact on the long-term follow-up of the diagnosis of MINOCA and its angiographic subtypes.

METHODS

We included 591 consecutive patients with non-ST-segment elevation myocardial infarction (NSTEMI) who underwent coronary angiography. MINOCA was classified according to angiographic findings as smooth coronary arteries, mild irregularities (< 30% stenosis), and moderate atherosclerosis (30%-49% stenosis). The primary endpoint was a composite of mortality, nonfatal myocardial infarction, and revascularization (MACE) at a median of 5 years of follow-up.

RESULTS

A total of 121 patients (20.5%) showed no obstructive lesions. MINOCA was associated with a lower occurrence of MACE (P=.014; HR, 0.63; 95%CI, 0.44-0.91) and was confirmed as an independent factor in the multivariate analysis (P=.018; HR, 0.63; 95%CI, 0.43-0.92). On analysis of the separate components of the main endpoint, MINOCA was significantly associated with a lower rate of myocardial infarction and revascularization, but not with mortality. Analysis of angiographic subtypes among MINOCA patients showed that smooth coronary arteries were a statistically significant protective factor on both univariate and multivariate analysis, while mild irregularities and 30% to 49% plaques were associated with a higher risk of MACE.

CONCLUSIONS

MINOCA is associated with a lower rate of MACE, driven by fewer reinfarctions and revascularizations. Within the angiographic subtypes of MINOCA, smooth arteries were independently associated with a lower number of MACE.

Intraoperative transit time flow measurements during off-pump coronary artery bypass surgery: The impact of coronary stenosis on competitive flow

Background

Combining preoperative angiography findings with intraoperative transit time flow measurements (TTFM) may improve patency of coronary artery bypass grafts. Nevertheless, graft flow might be impaired by native coronary flow based on the severity of stenoses, with inferior long‐term outcomes. This study investigates the impact of left anterior descending artery (LAD) stenosis on competitive flow measured in left internal mammary artery (LIMA) grafts during off‐pump coronary artery bypass grafting.

Methods

Fifty patients were included in this prospective single‐center cohort study. LAD stenosis was assessed with quantitative coronary analysis (QCA) and stratified into three groups based on its severity. TTFM of LIMA grafts were performed with LAD open and temporarily occluded. Change in mean graft flow after LAD snaring was the primary endpoint. Secondary endpoints included further TTFM parameters, clinical outcomes, and competitive flow index (CFI), defined as the ratio of mean graft flow with open or closed LAD.

Results

Mean LAD stenosis as objectified with QCA was 58 ± 15%. Mean LIMA graft flow increased from 20 ml/min with open LAD to 30 ml/min with snared LAD (p < .001). TTFM cut‐off values for graft patency improved in 26%–42% of patients after LAD occlusion. Median CFI was 0.66 (IQR: 0.56–0.82). Postoperative myocardial infarction occurred in 2.0% of patients, 120‐day mortality was 0%, and 2‐year mortality was 6.0%.

Conclusions

Routine snaring of the LAD with CFI calculation during coronary artery bypass grafting is useful to detect significant competitive flow in LIMA grafts, potentially preventing unnecessary intraoperative graft revisions.

The evolving role of cardiac imaging in patients with myocardial infarction and non-obstructive coronary arteries

Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA) represents a heterogeneous clinical conundrum accounting for about 6%-8% of all acute MI who are referred for coronary angiography. Current guidelines and consensus documents recommend that these patients are appropriately diagnosed, uncovering the causes of MINOCA, so that specific therapies can be prescribed. Indeed, there are a variety of causes that can result in this clinical condition, and for this reason diagnostic cardiac imaging has an emerging critical role in the assessment of patients with suspected or confirmed MINOCA. In last years, different cardiac imaging techniques have been evaluated in this context, and the comprehension of their strengths and limitations is of the utmost importance for their effective use in clinical practice. Moreover, recent evidence is clearly suggesting that a multimodality cardiac imaging approach, combining different techniques, seems to be crucial for a proper management of MINOCA. However, great variability still exists in clinical practice in the management of patients with suspected MINOCA, also depending on the availability of diagnostic tools and local expertise. Herein, we review the current knowledge supporting the use of different cardiac imaging techniques in patients with MINOCA, underscoring the importance of a comprehensive multimodality cardiac imaging approach and proposing a practical diagnostic algorithm to properly identify and treat the specific causes of MINOCA, in order to improve prognosis and the quality of life in these patients.

Dynamic Myocardial Perfusion CT for the Detection of Hemodynamically Significant Coronary Artery Disease

OBJECTIVES

In this international, multicenter study, using third-generation dual-source computed tomography (CT), we investigated the diagnostic performance of dynamic stress CT myocardial perfusion imaging (CT-MPI) in addition to coronary CT angiography (CTA) compared to invasive coronary angiography (ICA) and invasive fractional flow reserve (FFR).

BACKGROUND

CT-MPI combined with coronary CTA integrates coronary artery anatomy with inducible myocardial ischemia, showing promising results for the diagnosis of hemodynamically significant coronary artery disease in single-center studies.

METHODS

At 9 centers in Europe, Japan, and the United States, 132 patients scheduled for ICA were enrolled; 114 patients successfully completed coronary CTA, adenosine-stress dynamic CT-MPI, and ICA. Invasive FFR was performed in vessels with 25% to 90% stenosis. Data were analyzed by independent core laboratories. For the primary analysis, for each coronary artery the presence of hemodynamically significant obstruction was interpreted by coronary CTA with CT-MPI compared to coronary CTA alone, using an FFR of ≤0.80 and angiographic severity as reference. Territorial absolute myocardial blood flow (MBF) and relative MBF were compared using C-statistics.

RESULTS

ICA and FFR identified hemodynamically significant stenoses in 74 of 289 coronary vessels (26%). Coronary CTA with ≥50% stenosis demonstrated a per-vessel sensitivity, specificity, and accuracy for the detection of hemodynamically significant stenosis of 96% (95% CI: 91–100), 72% (95% CI: 66–78), and 78% (95% CI: 73–83), respectively. Coronary CTA with CT-MPI showed a lower sensitivity (84%; 95% CI: 75–92) but higher specificity (89%; 95% CI: 85–93) and accuracy (88%; 95% CI: 84–92). The areas under the receiver-operating characteristic curve of absolute MBF and relative MBF were 0.79 (95% CI: 0.71–0.86) and 0.82 (95% CI: 0.74–0.88), respectively. The median dose-length product of CT-MPI and coronary CTA were 313 mGy·cm and 138 mGy·cm, respectively.

CONCLUSIONS

Dynamic CT-MPI offers incremental diagnostic value over coronary CTA alone for the identification of hemodynamically significant coronary artery disease. Generalized results from this multicenter study encourage broader consideration of dynamic CT-MPI in clinical practice. (Dynamic Stress Perfusion CT for Detection of Inducible Myocardial Ischemia [SPECIFIC]; NCT02810795)

ANMCO POSITION PAPER: Prognostic and therapeutic relevance of non-obstructive coronary atherosclerosis

Atherosclerosis often affects the coronary arterial tree. Frequently the disease does not translate in significant narrowing of the vessels, thus determining only a non-obstructive disease. This condition that is described as non-obstructive coronary artery disease (NobsCAD) should be distinguished from the absence of disease (i.e. smooth coronary arteries) as it carries a specific prognostic value. The detection and reporting of NobsCAD should prompt preventive measures that can be individualized upon the degree of the underlying burden of disease. The accompanying clinical condition, the other cardiovascular risk factors present, and the description of the severity and extent of NobsCAD should provide the framework for an individualized treatment that should also consider the best available scientific evidence and guidelines. The description of NobsCAD represents important information to be collected whenever a coronary angiogram (both invasive and non-invasive) is performed. Treating the patient according to the presence and extent of NobsCAD offers prognostic benefits well beyond those offered by considering only the traditional cardiovascular risk factors. In order to reach this goal, NobsCAD should not be confused with the absence of coronary atherosclerosis or even ignored when detected as if it was a trivial information to provide.

Diagnostic pathways in myocardial infarction with non-obstructive coronary artery disease (MINOCA)

When acute myocardial injury is found in a clinical setting suggestive of myocardial ischaemia, the event is labelled as acute myocardial infarction (AMI), and the absence of coronary stenosis angiographically 50% or greater leads to the working diagnosis of myocardial infarction with non-obstructive coronary arteries (MINOCA). The initial diagnosis of MINOCA can be confirmed or ruled out based on the results of subsequent investigations. This narrative review discusses the downstream diagnostic approaches to MINOCA, and appraises strengths and limitations of invasive and non-invasive investigations for this condition. The aim of this article is to increase the awareness that establishing the underlying cause of a MINOCA is possible in the vast majority cases. Determining the cause of MINOCA and excluding other possible causes for cardiac troponin elevation has notable implications for tailoring secondary prevention measures aimed at improving the overall prognosis of AMI.

Mis-estimation of coronary lesions and rectification by SYNTAX score feedback for coronary revascularization appropriateness

BACKGROUND

Imprecise interpretation of coronary angiograms was reported and resulted in inappropriate revascularization. Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score is a comprehensive system to evaluate the complexity of the overall lesions. We hypothesized that a real-time SYNTAX score feedback from image analysts may rectify the mis-estimation and improve revascularization appropriateness in patients with stable coronary artery disease (CAD).

METHODS

In this single-center, historical control study, patients with stable CAD with coronary lesion stenosis ≥50% were consecutively recruited. During the control period, SYNTAX scores were calculated by treating cardiologists. During the intervention period, SYNTAX scores were calculated by image analysts immediately after coronary angiography and were provided to cardiologists in real-time to aid decision-making. The primary outcome was revascularization deemed inappropriate by Chinese appropriate use criteria for coronary revascularization.

RESULTS

A total of 3245 patients were enrolled and assigned to the control group (08/2016-03/2017, n = 1525) or the intervention group (03/2017-09/2017, n = 1720). For SYNTAX score tertiles, 17.9% patients were overestimated and 4.3% were underestimated by cardiologists in the control group. After adjustment, inappropriate revascularization significantly decreased in the intervention group compared with the control group (adjusted odds ratio [OR]: 0.83; 95% confidence interval [CI]: 0.73-0.95; P = 0.007). Both inappropriate percutaneous coronary intervention (adjusted OR: 0.82; 95% CI: 0.74-0.92; P < 0.001) and percutaneous coronary intervention utilization (adjusted OR: 0.88; 95% CI: 0.79-0.98; P = 0.016) decreased significantly in the intervention group. There was no significant difference in 1-year adverse cardiac events between the control group and the intervention group.

CONCLUSIONS

Real-time SYNTAX score feedback significantly reduced inappropriate coronary revascularization in stable patients with CAD.

CLINICAL TRIAL REGISTRATION

Nos. NCT03068858 and NCT02880605; https://www.clinicaltrials.gov.

Invasive coronary physiology assessment for patients with stable coronary disease

Visual assessment of coronary stenosis severity using conventional coronary angiography is associated with wide inter-operator variability and a weak relationship with hemodynamics. Invasive coronary physiology assessment using fractional flow reserve (FFR) has been shown to be safe and beneficial. Large multicenter randomized trials have demonstrated the superiority of FFR-guided percutaneous coronary intervention (PCI) in reducing the risk of major cardiac adverse events, number of stents used, and total cost in patients with multi-vessel coronary disease. FFR requires vasodilatory agents for the microvasculature to induce maximal hyperemia, which carry a slight risk, cost, and effort. Non-hyperemic pressure ratios (NHPR) provide a physiologic metric without vasodilator medications but with more limited clinical outcomes data. The transition from anatomy to physiology for CAD decision-making represents a cultural sea change in the cardiac catheterization laboratory that requires time and retooling.

Comparison of Patients With Nonobstructive Coronary Artery Disease With Versus Without Myocardial Infarction (from the VA Clinical Assessment Reporting and Tracking [CART] Program)

Comparisons of the outcomes of patients with myocardial infarction with nonobstructive coronary artery disease (MINOCA) and patients with nonobstructive coronary artery disease (CAD) without myocardial infarction (MI) are limited. Here we compare the outcomes of patients with MINOCA and patients with nonobstructive CAD without MI and assess the influence of medical therapy on outcomes in these patients. Veterans who underwent coronary angiography between 2008 to 2017 with nonobstructive CAD were divided into those with or without pre-procedural troponin elevation. Patients with prior revascularization, heart failure, or who presented with cardiogenic shock, STEMI, or unstable angina were excluded. After propensity matching, outcomes were compared between groups. The primary outcome was major adverse cardiovascular events (MACE: mortality, myocardial infarction, and revascularization) within one year: 3,924 patients with nonobstructive CAD and a troponin obtained prior to angiography were identified (n=1,986 with elevated troponin) and restricted to 1,904 patients after propensity-matching. There was a significantly higher risk of MACE among troponin-positive patients compared with those with a negative troponin (HR 2.37; 95% CI, 1.67 to 3.34). Statin (HR 0.32; 95% CI, 0.22 to 0.49) and ACE inhibitor (HR 0.49; 95% CI, 0.32 to 0.75) therapy after angiography was associated with decreased MACE, while P2Y12 inhibitor, calcium-channel and beta-blocker therapy were not associated with outcomes. In conclusion, Veterans with MINOCA are at increased risk for MACE compared with those with nonobstructive CAD and negative troponin at the time of angiography. Specific medications were associated with a reduction in MACE, suggesting an opportunity to explore novel approaches for secondary prevention in this population.

Standardizing the Definition and Analysis Methodology for Complete Coronary Artery Revascularization

Guideline‐based medical therapy is the foundation of treatment for individuals with coronary artery disease. However, revascularization with either percutaneous coronary intervention or coronary artery bypass grafting may be beneficial in patients with acute coronary syndromes, refractory symptoms, or in other specific scenarios (eg, left main disease and heart failure). While the goal of percutaneous coronary intervention and coronary artery bypass grafting is to achieve complete revascularization, anatomical and ischemic definitions of complete revascularization and their methodology for assessment remain highly variable. Such lack of consensus invariably contributes to the absence of standardized approaches for invasive treatment of coronary artery disease. Herein, we propose a novel, comprehensive, yet pragmatic algorithm with both anatomical and ischemic parameters that aims to provide a systematic method to assess complete revascularization after percutaneous coronary intervention or coronary artery bypass grafting in both clinical practice and clinical trials.

Early Feasibility of Automated Artificial Intelligence Angiography Based Fractional Flow Reserve Estimation

Despite the evidence of improved patients' outcome, fractional flow reserve (FFR) is underused in current everyday practice. We aimed to evaluate the feasibility of a novel automated artificial intelligence angiography-based FFR software (AutocathFFR) as a decision supporting tool for interventional cardiologists. AutocathFFR was performed on angiographic images of patients who underwent coronary angiography with a pressure wire FFR measurement. Sensitivity and specificity for detection of FFR cut-off of 0.8 were calculated. Thirty-one patients were included in the present study, with a mean age of 64 ± 10 years, 80% were males, 32% patients had diabetes, 39% had previous percutaneous coronary intervention. The left anterior descending artery was the target vessel in 80% of patients. Automatic lesion detection was successful in all of the lesions with FFR value of ≤0.8. The sensitivity of AutocathFFR for predicting a wire based FFR ≤0.8 was 88% and the specificity for FFR >0.8 was 93%, with a positive predictive value of 94% and negative predictive value of 87%, indicating an accuracy level of 90% and area under the curve of 0.91. AutocathFFR has excellent accuracy in prediction of wire based FFR and is a promising technology that may facilitate appropriate decision and treatment choices for coronary artery disease patients.

Visually Estimated RESOLVE Score Based on Coronary Computed Tomography to Predict Side Branch Occlusion in Percutaneous Bifurcation Intervention

PURPOSE

The quantitative RESOLVE (Risk prEdiction of Side branch OccLusion in coronary bifurcation interVEntion) score derived from coronary computed tomography angiography (coronary CTA) was developed as a noninvasive and accurate prediction tool for side branch (SB) occlusion in coronary bifurcation intervention. We aimed to determine the ability of a visually estimated CTA-derived RESOLVE score (V-RESOLVE score) to predict SB occlusion in coronary bifurcation intervention.

MATERIALS AND METHODS

The present study included 363 patients with 400 bifurcation lesions. CTA-derived V-RESOLVE score was derived and compared with the quantitative CTA-derived RESOLVE score. The scoring systems were divided into quartiles, and classified as the high-risk and non-high-risk groups. SB occlusion was defined as any decrease in thrombolysis in myocardial infarction flow grade after main vessel stenting.

RESULTS

In total, 28 SB occlusions (7%) occurred. The concordance between visual and quantitative CTA analysis showed poor to excellent agreement (weighted κ range: 0.099 to 0.867). The area under the receiver operating curve for the prediction of SB occlusion was significantly higher for the CTA-derived V-RESOLVE score than for quantitative CTA-derived RESOLVE score (0.792 vs. 0.709, P=0.049). The total net reclassification index was 42.7% (P=0.006), and CTA-derived V-RESOLVE score showed similar capability to discriminate between high-risk group (18.6% vs. 13.8%, P=0.384) and non-high-risk group (3.8% vs. 4.9%, P=0.510) as compared with quantitative CTA-derived RESOLVE score.

CONCLUSIONS

Visually estimated CTA-derived V-RESOLVE score is an accurate and easy-to-use prediction tool for the stratification of SB occlusion in coronary bifurcation intervention.

The case for a qualitative lesion assessment system for coronary angiography

Since the advent of coronary angiography, the standard for reporting of coronary lesion severity has been to utilize percent diameter stenosis (%DS). Given the imperfections of %DS as well as the widespread availability of intraprocedural intracoronary imaging and physiology assessment, it is time to consider a simpler yet more clinically relevant lesion assessment system. We compiled ten actual cases and presented these cases to 10 operators, providing 100 independent lesion assessments. For each case, operators were asked to describe lesions using %DS and a simplified lesion assessment system. We assessed the relationship between %DS and qualitative lesion assessment as well as the relationship of both measurements to the chosen plan. Greater variability exists with %DS than with qualitative lesion assessment. Despite this, there is good correlation between %DS and the qualitative lesion assessment (ρ = 0.8221). There remains overlap of lesion assessment using the qualitative lesion assessment tool suggesting that even with this simpler tool, there remains interobserver variability (ICC = 0.5164, 95% confidence interval [CI] 0.2924-0.7955). When assessing how both lesion assessment, there appears to be a stronger correlation between the qualitative lesion assessment and the chosen plan versus the %DS and the chosen plan (ρ = 0.9069 vs ρ = 0.8001, P < .01). Given the superior performance of the proposed qualitative system and the ability to estimate lesion severity using both anatomic and clinical factors, we feel that professional societies and clinicians should begin to embrace this simplified means of lesion assessment.

Stress myocardial perfusion with qualitative magnetic resonance and quantitative dynamic computed tomography: comparison of diagnostic performance and incremental value over coronary computed tomography angiography

AIMS

Assessment of haemodynamically significant coronary artery disease (CAD) using cardiovascular magnetic resonance (CMR) imaging perfusion or dynamic stress myocardial perfusion imaging by computed tomography (CT perfusion) may aid patient selection for invasive coronary angiography (ICA). We evaluated the diagnostic performance and incremental value of qualitative CMR perfusion and quantitative CT perfusion complementary to cardiac computed tomography angiography (CCTA) for the diagnosis of haemodynamically significant CAD using fractional flow reserve (FFR) and quantitative coronary angiography (QCA) as reference standard.

METHODS AND RESULTS

CCTA, qualitative visual CMR perfusion, visual CT perfusion, and quantitative relative myocardial blood flow (CT-MBF) were performed in patients with stable angina pectoris. FFR was measured in coronary vessels with stenosis visually estimated between 30% and 90% diameter reduction on ICA. Haemodynamically significant CAD was defined as FFR <0.80, or QCA ≥80% in those cases where FFR could not be performed. A total of 218 vessels from 93 patients were assessed. An optimal cut-off of 0.72 for relative CT-MBF was determined. The diagnostic performances (area under the receiver-operating characteristics curves, 95% CI) of visual CMR perfusion (0.84, 0.77-0.90) and relative CT-MBF (0.86, 0.81-0.92) were comparable and outperformed visual CT perfusion (0.64, 0.57-0.71). In combination with CCTA ≥50%, CCTA + visual CMR perfusion (0.91, 0.86-0.96), CCTA + relative CT-MBF (0.92, 0.88-0.96), and CCTA + visual CT perfusion (0.82, 0.75-0.90) improved discrimination compared with CCTA alone (all P < 0.05).

CONCLUSION

Visual CMR perfusion and relative CT-MBF outperformed visual CT perfusion and provided incremental discrimination compared with CCTA alone for the diagnosis of haemodynamically significant CAD.

CCTA in the diagnosis of coronary artery disease

The world of cardiac imaging is proposing to physicians an ever-increasing spectrum of options and tools with the disadvantages of patients presently submitted to multiple, sequential, time-consuming, and costly diagnostic procedures and tests, sometimes with contradicting results. In the last two decades, the CCTA has evolved into a valuable diagnostic test in today's patient care, changing the official existing guidelines and clinical practice with a pivotal role to exclude significant CAD, in the referral of patients to the Cath-Lab, in the follow-up after coronary revascularization, and finally in the cardiovascular risk stratification.

Myocardial Infarction With Nonobstructive Coronary Arteries

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is the current term used to describe patients who have a myocardial infarction but have normal, non-obstructed coronary arteries on a coronary angiogram. There is still much debate over the definition, diagnosis, management and treatment of MINOCA. However, MINOCA is not a benign condition; prompt recognition and diagnosis can lead to better management and treatment and thus improve patient outcomes. This review article will update the most recent definition of MINOCA, discuss epidemiology and etiology, and review the diagnostic workup and management options for patients presenting with signs and symptoms of MINOCA.

Nonculprit Lesion Severity and Outcome of Revascularization in Patients With STEMI and Multivessel Coronary Disease

BACKGROUND

In the COMPLETE (Complete vs Culprit-only Revascularization to Treat Multi-vessel Disease After Early PCI for STEMI) trial, angiography-guided percutaneous coronary intervention (PCI) of nonculprit lesions with the aim of complete revascularization reduced major cardiovascular (CV) events in patients with ST-segment elevation myocardial infarction (MI) and multivessel coronary artery disease.

OBJECTIVES

The purpose of this study was to determine the effect of nonculprit-lesion stenosis severity measured by quantitative coronary angiography (QCA) on the benefit of complete revascularization.

METHODS

Among 4,041 patients randomized in the COMPLETE trial, nonculprit lesion stenosis severity was measured using QCA in the angiographic core laboratory in 3,851 patients with 5,355 nonculprit lesions. In pre-specified analyses, the treatment effect in patients with QCA stenosis ≥60% versus <60% on the first coprimary outcome of CV death or new MI and the second co-primary outcome of CV death, new MI, or ischemia-driven revascularization was determined.

RESULTS

The first coprimary outcome was reduced with complete revascularization in the 2,479 patients with QCA stenosis ≥60% (2.5%/year vs. 4.2%/year; hazard ratio [HR]: 0.61; 95% confidence interval [CI]: 0.47 to 0.79), but not in the 1,372 patients with QCA stenosis <60% (3.0%/year vs. 2.9%/year; HR: 1.04; 95% CI: 0.72 to 1.50; interaction p = 0.02). The second coprimary outcome was reduced in patients with QCA stenosis ≥60% (2.9%/year vs. 6.9%/year; HR: 0.43; 95% CI: 0.34 to 0.54) to a greater extent than patients with QCA stenosis <60% (3.3%/year vs. 5.2%/year; HR: 0.65; 95% CI: 0.47 to 0.89; interaction p = 0.04).

CONCLUSIONS

Among patients with ST-segment elevation MI and multivessel coronary artery disease, complete revascularization reduced major CV outcomes to a greater extent in patients with stenosis severity of ≥60% compared with <60%, as determined by quantitative coronary angiography.

Comprehensive Geriatric Assessment in the Management of Older Patients With Cardiovascular Disease

Cardiovascular disease (CVD) disproportionately affects older adults. It is expected that by 2030, one in five people in the United States will be older than 65 years. Individuals with CVD now live longer due, in part, to current prevention and treatment approaches. Addressing the needs of older individuals requires inclusion and assessment of frailty, multimorbidity, depression, quality of life, and cognition. Despite the conceptual relevance and prognostic importance of these factors, they are seldom formally evaluated in clinical practice. Further, although these constructs coexist with traditional cardiovascular risk factors, their exact prevalence and prognostic impact remain largely unknown. Development of the right decision tools, which include these variables, can facilitate patient-centered care for older adults. These gaps in knowledge hinder optimal care use and underscore the need to rigorously evaluate the optimal constructs for providing care to older adults. In this review, we describe available tools to examine the prognostic role of age-related factors in patients with CVD.

Intravascular Ultrasound Imaging-Guided Versus Coronary Angiography-Guided Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis

Background

Intravascular ultrasound (IVUS) guidance during percutaneous coronary intervention (PCI) offers tomographic images of the coronary vessels, allowing optimization of stent implantation at the time of PCI. However, the long‐term beneficial effect of IVUS over PCI guided by coronary angiography (CA) alone remains under question. We sought to investigate the outcomes of IVUS‐guided compared with CA‐guided PCI.

Methods and Results

We performed a comprehensive search of PubMed, Medline, and Cochrane Central Register, looking for randomized controlled trials and observational studies that compared PCI outcomes of IVUS with CA. Data were aggregated for the primary outcome measure using the random‐effects model as pooled risk ratio (RR). The primary outcomes were the rate of cardiovascular death, need for target lesion revascularization, occurrence of myocardial infarction, and rate of stent thrombosis. A total of 19 studies met the inclusion criteria, comprising 27 610 patients divided into IVUS (n=11 513) and CA (n=16 097). Compared with standard CA‐guided PCI, we found that the risks of cardiovascular death (RR, 0.63; 95% CI, 0.54–0.73), myocardial infarction (RR, 0.71; 95% CI, 0.58–0.86), target lesion revascularization (RR, 0.81; 95% CI, 0.70–0.94), and stent thrombosis (RR, 0.57; 95% CI, 0.41–0.79) were all significantly lower using IVUS guidance.

Conclusions

Compared with standard CA‐guided PCI, the use of IVUS imaging guidance to optimize stent implantation is associated with a reduced risk of cardiovascular death and major adverse events, such as myocardial infarction, target lesion revascularization, and stent thrombosis.

Fifteen years of coronary intravascular ultrasound in percutaneous coronary intervention in Portugal

INTRODUCTION

Coronary intravascular ultrasound (IVUS) is increasingly important in catheterization laboratories due to its positive prognostic impact. This study aims to characterize the use of IVUS in percutaneous coronary intervention (PCI) in Portugal.

METHODS

A retrospective observational study was performed based on the Portuguese Registry on Interventional Cardiology of the Portuguese Society of Cardiology. The clinical and angiographic profiles of patients who underwent PCI between 2002 and 2016, the percentage of IVUS use, and the coronary arteries assessed were characterized.

RESULTS

A total of 118 706 PCIs were included, in which IVUS was used in 2266 (1.9%). Over time, use of IVUS changed from none in 2002 to generally increasing use from 2003 (0.1%) to 2016 (2.4%). The age of patients in whom coronary IVUS was used was similar to that of patients in whom IVUS was not used, but in the former group there were fewer male patients, and a higher prevalence of cardiovascular risk factors (hypertension, hypercholesterolemia and diabetes), previous myocardial infarction, previous PCI, multivessel coronary disease, C-type or bifurcated coronary lesions, and in-stent restenosis. IVUS was used in 54.8% of elective PCIs and in 19.15% of PCIs of the left main coronary artery.

CONCLUSION

Coronary IVUS has been increasingly used in Portugal since 2003. It is used preferentially in elective PCIs, and in patients with higher cardiovascular risk, with more complex coronary lesions and lesions of the left main coronary artery.

Intracoronary Imaging for Assessment of Vascular Healing and Stent Follow-up in Bioresorbable Vascular Scaffolds

Bioresorbable Vascular Scaffolds (BVS) are polymer-based materials implanted in the coronary arteries in order to treat atherosclerotic lesions, based on the concept that once the lesion has been treated, the material of the implanted stent will undergo a process of gradual resorption that will leave, in several years, the vessel wall smooth, free of any foreign material and with its vasomotion restored. However, after the first enthusiastic reports on the efficacy of BVSs, the recently published trials demonstrated disappointing results regarding long-term patency following BVS implantation, which were mainly attributed to technical deficiencies during the stenting procedure. Intracoronary imaging could play a crucial role for helping the operator to correctly implant a BVS into the coronary artery, as well as providing relevant information in the follow-up period. This review aims to summarize the role of intracoronary imaging in the follow-up of coronary stents, with a particular emphasis on the role of intravascular ultrasound and optical coherence tomography for procedural guidance during stent implantation and also for follow-up of bioabsorbable scaffolds.

Accuracy of 3-dimensional and 2-dimensional quantitative coronary angiography for predicting physiological significance of coronary stenosis: a FAVOR II substudy

Background

Three-dimensional quantitative coronary angiography (3D-QCA) enables reconstruction of a coronary artery in 3D from two angiographic image projections. This study compared the diagnostic accuracy of 3D-QCA vs. 2-dimensional (2D) QCA in predicting physiologically significant coronary stenosis, using fractional flow reserve (FFR) as the reference standard.

Methods

All interrogated vessels in the FAVOR II China study and the FAVOR II Europe-Japan study were assessed by 2D-QCA and 3D-QCA according to standard operating procedures in core laboratories. QCA analysts were blinded to the corresponding FFR values.

Results

A total of 645 vessels from 576 patients with 3D-QCA, 2D-QCA, and FFR were analyzed. Using the conventional cut-off value of 50% for percent diameter stenosis (DS%), 3D-QCA was more accurate in predicting FFR ≤0.80 than 2D-QCA [accuracy 74.0% (95% CI: 69.9-77.7%) vs. 64.9% (95% CI: 61.3-68.7%), difference: 9.1%, P<0.001]. Sensitivity was higher by 3D-QCA compared with 2D-QCA [69.1% (95% CI: 63.0-75.1%) vs. 47.1% (95% CI: 40.5-53.6%), difference: 22.0%, P<0.001] and specificity was similar [76.5% (95% CI: 72.5-80.6%) vs. 74.4% (95% CI: 70.2-78.6%), difference: 2.1%, P=0.40]. Area under the receiver operating characteristic curve was significantly higher for 3D-QCA than for 2D-QCA [0.81 (95% CI: 0.77-0.84) vs. 0.66 (95% CI: 0.62-0.71), P<0.001].

Conclusions

3D-QCA demonstrated better diagnostic performance in predicting physiologically significant coronary stenosis compared with 2D-QCA, when FFR was used as the reference standard.

Short-Term and Long-Term Efficacy of Drug-Coated Balloon for In-Stent Restenosis in Hemodialysis Patients with Coronary Artery Disease

The efficacy of drug-coated balloons (DCB) for in-stent restenosis (ISR) in hemodialysis (HD) patients remains unclear.We retrospectively evaluated 153 consecutive patients who underwent DCB for ISR with follow-ups for up to 3 years after the procedure between February 2014 and June 2017. Patients were divided into an HD group (n = 39) and a non-HD group (n = 114). The primary endpoint was target lesion revascularization (TLR). The secondary endpoints were all revascularizations and major adverse cardiac events (MACE) defined as cardiac death, myocardial infarction and cerebral infarction. Kaplan-Meier curves of survival free from TLR were compared between the two groups. We also performed propensity score matching and then compared the two matched groups (n = 27 in each group). The acute procedure success rate was similar for the two groups (100% versus 99.1%, P = 0.56). The incidence of TLR was higher in the HD group than in the non-HD group (41.0% versus 9.6%, P < 0.0001). The rate of revascularizations and MACE combined was significantly higher in the HD group than in the non-HD group (64.1% versus 17.5%, P < 0.0001). Kaplan-Meier analyses showed that survival free from TLR was significantly lower in the HD group than in the non-HD group both before and after propensity score matching (P < 0.0001 and P = 0.005, respectively; log-rank test).Contrary to the similar acute procedure success, recurrent ISR and MACE occurred more frequently in HD patients than in non-HD patients after DCB, which indicates poorer long-term efficacy of DCB in HD patients.

Detection of Hemodynamically Significant Coronary Stenosis: CT Myocardial Perfusion versus Machine Learning CT Fractional Flow Reserve

Background Direct intraindividual comparison of dynamic CT myocardial perfusion imaging (MPI) and machine learning (ML)-based CT fractional flow reserve (FFR) has not been explored for diagnosing hemodynamically significant coronary artery disease. Purpose To investigate the diagnostic performance of dynamic CT MPI and ML-based CT FFR for functional assessment of coronary stenosis. Materials and Methods Between January 2, 2017, and October 17, 2018, consecutive participants with stable angina were prospectively enrolled. All participants underwent dynamic CT MPI coronary CT angiography and invasive conventional coronary angiography (CCA) FFR within 2 weeks. Receiver operating characteristic (ROC) curve analysis was used to assess diagnostic performance. Results Eighty-six participants (mean age, 67 years ± 12 [standard deviation]; 67 men) with 157 target vessels were included for final analysis. The mean radiation doses for dynamic CT MPI and coronary CT angiography were 3.6 mSv ± 1.1 and 2.7 mSv ± 0.8, respectively. Myocardial blood flow (MBF) was lower in ischemic segments compared with nonischemic segments and reference segments (defined as the territory of vessels without stenosis) (75 mL/100 mL/min ± 20 vs 148 mL/100 mL/min ± 22 and 169 mL/100 mL/min ± 34, respectively, both P < .001). Similarly, CT FFR was also lower for hemodynamically significant lesions than for hemodynamically nonsignificant lesions (0.68 ± 0.1 vs 0.83 ± 0.1, respectively, P < .001). MBF had the largest area under the ROC curve (AUC) (using 99 mL/100 mL/min as a cutoff) among all parameters, outperforming ML-based CT FFR (AUC = 0.97 vs 0.85, P < .001). The vessel-based specificity and diagnostic accuracy of MBF were higher than those of ML-based CT FFR (93% vs 68%, P < .001 and 94% vs 78%, respectively, P = .04) whereas the sensitivity of both methods was similar (96% vs 88%, respectively, P = .11). Conclusion Dynamic CT myocardial perfusion imaging was able to help accurately evaluate the hemodynamic significance of coronary stenosis using a reduced amount of radiation. In addition, the myocardial blood flow derived from dynamic CT myocardial perfusion imaging outperformed machine learning-based CT fractional flow reserve for identifying lesions causing ischemia. © RSNA, 2019 Online supplemental material is available for this article.See also the editorial by Loewe in this issue.

Application of the DILEMMA score to improve lesion selection for invasive physiological assessment

OBJECTIVES

We sought to assess the validity of the DILEMMA score against instantaneous wave-free ratio (iFR) and evaluate its utility in rationalizing the number of patients referred for invasive physiological assessment.

BACKGROUND

The DILEMMA score is a validated angiographic scoring tool incorporating minimal lumen diameter, lesion length and subtended myocardial area that has been shown to predict the functional significance of lesions as assessed by fractional flow reserve (FFR).

METHODS

Patients in the DEFINE-FLAIR study who had coronary stenosis of intermediate severity were randomized to either FFR or iFR. DILEMMA score was calculated retrospectively on a subset of this cohort by operators blinded to FFR or iFR values.

RESULTS

Three hundred and forty-six lesions (181 assessed by FFR; 165 by iFR) from 259 patients (mean age 66.0 years, 79% male) were included. A DILEMMA score ≤ 2 had a negative predictive value of 96.3% and 95.7% for identifying lesions with FFR >0.80 and iFR >0.89, respectively. A DILEMMA score ≥ 9 had a positive predictive value of 88.9% and 100% for identifying lesions with FFR ≤0.80 and iFR ≤0.89, respectively. The receiver operating characteristic area under the curve values for DILEMMA score to predict FFR ≤0.80 and iFR ≤0.89 were 0.83 (95% CI 0.77-0.90) and 0.82 (0.75-0.89) respectively. A DILEMMA score ≤ 2 or ≥9 occurred in 172 of the 346 lesions (49.7%).

CONCLUSIONS

Using DILEMMA score in patients with coronary stenosis of intermediate severity may reduce the need for pressure wire use, offering potential cost-savings and minimizing the risks associated with invasive physiological lesion assessment.