The SYNTAX Score and SYNTAX-Based Clinical Risk Scores

Assessment of left ventricular global longitudinal strain in patients with hypertrophic cardiomyopathy and coronary artery disease

Impaired left ventricular global longitudinal strain (GLS) and coronary artery disease (CAD) each confer adverse prognosis in hypertrophic cardiomyopathy (HCM). Despite their prevalence, data on GLS in co-existent HCM and CAD is lacking. Ninety-six patients with HCM and CAD were retrospectively identified between 2005 and 2021, and analyzed using 2D speckle-tracking echocardiography. Obstructive and non-obstructive CAD patients were compared, multivariate linear regression tested associations between clinical and echocardiographic variables with GLS, and Receiver Operating Characteristic Curve assessed the utility of GLS to predict all-cause mortality at follow-up. Mean age was 71 ± 12.2 years, 41% had obstructive HCM, 78% had obstructive CAD, and 75% had prior acute coronary syndrome. At 4.8-year follow-up, GLS decreased compared with baseline (- 12.5 ± 4.5 vs. - 14 ± 4.2%, p = 0.007), with basal segments experiencing the greatest impairment. GLS was lower in obstructive versus non-obstructive CAD patients at follow-up, although the magnitude was attenuated (baseline: - 13.2 vs. - 17.1%, p < 0.001; follow-up: - 12 vs. - 14.1%, p = 0.05). Interventricular septal thickness (β = 0.54), apical HCM (β = 0.48), and right ventricular systolic pressure (β = 0.39) were associated with more impaired GLS (all p < 0.001), independent of obstructive CAD (β = 0.09, p = 0.44). There were 9 follow-up deaths, with baseline GLS > - 13.5% being a good predictor of all-cause mortality (AUC 0.78, 95% CI 0.64-0.92, sensitivity 88%, specificity 57%, p = 0.01). Patients with HCM and CAD experience progressive GLS impairment over long-term follow-up, with GLS > - 13.5% appearing to be a threshold for predicting all-cause mortality. Apical HCM phenotype is independently associated with worse GLS.

The Clinical SYNTAX score predicts survival better than the SYNTAX score in coronary revascularization

BACKGROUND

The Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery (SYNTAX) trial showed that the SYNTAX score (SS) is a useful tool for customizing revascularization treatment for patients with multivessel coronary disease. In the past decade, the Clinical SS (CSS) has emerged as a comprehensive tool. This novel tool considers the SS as well as patient clinical parameters such as age, creatinine clearance, and ejection fraction, which were shown to be relevant for patient prognosis. Thus, in the current work we set out to compare the survival predictive values of the SS versus the CSS and their future application in real-world implementation of the revascularization guidelines.

METHODS

This study was a subanalysis of data collected in a prospective national registry in Israel that enrolled consecutive patients with left main and/or 2- to 3-vessel coronary artery disease involving the proximal or mid-left anterior descending artery; the MULTI-vessel Coronary Artery Disease (MULTICAD). The revascularization method was chosen by the physicians taking care of the patients at each hospital and the patients were followed for 5 years. Patients were categorized according to their SS, the CSS, and their revascularization method (primary coronary intervention [PCI] vs coronary artery bypass grafting [CABG]) and patient survival were compared.

RESULTS

A total of 585 patients were enrolled in the study and were followed for 5 years. The median CSS was 27, with 288 patients showing a CSS ≥27, with a mean CSS of 47.85 and a mean SS of 29.05. At 3 and 5 years post-treatment, the CSS ≥27 group had a lower survival probability, CSS ≥27 was associated with a lower survival probability among patients who underwent PCI compared with those who underwent CABG. More specifically, the high-CSS CABG group had a 5-year mortality rate of 16.8%, whereas the high-CSS PCI group had a 5-year mortality rate of 32.2%. In a comparison of SS with CSS for the 5-year mortality outcome prediction, CSS was superior to SS with a higher area under the curve.

CONCLUSIONS

This prospective registry of real-world revascularization strategies in patients with multivessel disease showed that CSS is a better predictive tool of postrevascularization survival than SS. Moreover, it showed that surgical revascularization in patients with CSS ≥27 is associated with better all-cause mortality outcome after CABG as compared with after PCI. This attests to the need for a score that considers clinical parameters in a real-world scenario.

Current and Future Applications of Artificial Intelligence in Coronary Artery Disease

Cardiovascular diseases (CVDs) carry significant morbidity and mortality and are associated with substantial economic burden on healthcare systems around the world. Coronary artery disease, as one disease entity under the CVDs umbrella, had a prevalence of 7.2% among adults in the United States and incurred a financial burden of 360 billion US dollars in the years 2016–2017. The introduction of artificial intelligence (AI) and machine learning over the last two decades has unlocked new dimensions in the field of cardiovascular medicine. From automatic interpretations of heart rhythm disorders via smartwatches, to assisting in complex decision-making, AI has quickly expanded its realms in medicine and has demonstrated itself as a promising tool in helping clinicians guide treatment decisions. Understanding complex genetic interactions and developing clinical risk prediction models, advanced cardiac imaging, and improving mortality outcomes are just a few areas where AI has been applied in the domain of coronary artery disease. Through this review, we sought to summarize the advances in AI relating to coronary artery disease, current limitations, and future perspectives.

Real-time coronary artery stenosis detection based on modern neural networks

Invasive coronary angiography remains the gold standard for diagnosing coronary artery disease, which may be complicated by both, patient-specific anatomy and image quality. Deep learning techniques aimed at detecting coronary artery stenoses may facilitate the diagnosis. However, previous studies have failed to achieve superior accuracy and performance for real-time labeling. Our study is aimed at confirming the feasibility of real-time coronary artery stenosis detection using deep learning methods. To reach this goal we trained and tested eight promising detectors based on different neural network architectures (MobileNet, ResNet-50, ResNet-101, Inception ResNet, NASNet) using clinical angiography data of 100 patients. Three neural networks have demonstrated superior results. The network based on Faster-RCNN Inception ResNet V2 is the most accurate and it achieved the mean Average Precision of 0.95, F1-score 0.96 and the slowest prediction rate of 3 fps on the validation subset. The relatively lightweight SSD MobileNet V2 network proved itself as the fastest one with a low mAP of 0.83, F1-score of 0.80 and a mean prediction rate of 38 fps. The model based on RFCN ResNet-101 V2 has demonstrated an optimal accuracy-to-speed ratio. Its mAP makes up 0.94, F1-score 0.96 while the prediction speed is 10 fps. The resultant performance-accuracy balance of the modern neural networks has confirmed the feasibility of real-time coronary artery stenosis detection supporting the decision-making process of the Heart Team interpreting coronary angiography findings.

Clinical SYNTAX score predicts outcomes of patients undergoing coronary artery bypass grafting

BACKGROUND

The SYNTAX score (SS) is a determinant of outcome in patients undergoing percutaneous coronary intervention. In addition, it has been recently shown that the clinical SYNTAX score (cSS), obtained by adding clinical variables to the SS, improves the predictive power of the resulting risk model. We assessed the hypothesis that the use of the cSS may predict outcomes of patients undergoing coronary artery bypass grafting (CABG).

METHODS

We measured the SYNTAX score in 874 patients undergoing isolated first time on-pump CABG. The clinical SYNTAX score was calculated at the time of the study using age, creatinine clearance and ejection fraction, the modified ACEF score, and analyses performed for major adverse cardiac and cerebrovascular events (MACCE) and all-cause mortality at 3-year follow-up.

RESULTS

The mean age of the study population was 70.9 ± 8.1 years, and the median cSS 14.2 (range 2.1-286.5). The ROC curve analysis showed that a cSS >14.5 (81.4% sensitivity and 67.8% specificity) was a reliable tool in discrimination of patients for the occurrence of MACCE (AUC 0.78) and all-cause mortality (AUC 0.74). Kaplan-Meier survival analysis confirmed that patients belonging to higher cSS quartiles have poorer 3-year survival (P = .0001) and MACCE-free survival (P = .0001), with respect to those with lower cSS.

CONCLUSIONS

This observational study has shown that the clinical SYNTAX score, incorporating the lesion-based SS and clinical-based ACEF score, predicted mid-term adverse outcomes of patients undergoing CABG and may play an important role in the risk stratification of this population. Further studies are needed to confirm these findings.

Prognostic Value of the Clinical SYNTAX Score on 2-Year Outcomes in Patients With Acute Coronary Syndrome Who Underwent Percutaneous Coronary Intervention

This prospective, single-center, observational study evaluated prognostic value of clinical SYNTAX score (CSS) on 2-year outcomes in patients with acute coronary syndrome (ACS) who underwent percutaneous coronary intervention (PCI). The SYNTAX score (SS) is a scoring system based on the complexity and severity of coronary lesions and is thought to be a prognostic tool to predict long-term outcomes. However, SS was a sole angiographic grading tool only with no consideration for clinical factors. There are few studies investigating the prognostic value of CSS in patients with ACS who underwent PCI. From January 2013 to December 2013, 6,099 consecutive patients with ACS admitted to FuWai hospital and underwent PCI were enrolled in this study. Based on CSS, patients were divided into low CSS group (CSS ≤ 6.5; 2,012 patients), mid-CSS group (6.5 < CSS < 13.8; 2,056 patients), and high CSS group (CSS ≥ 13.8; 2,031 patients). At 2-year follow-up, rates of cardiac death and major adverse cardiac events (MACE) were significantly higher in the high CSS group. Compared with baseline SS, CSS demonstrated significantly improved performance for 2-year cardiac death (receiver-operating characteristic curve C-statistic: 0.74 vs 0.62, p <0.001) but not for MACE (receiver-operating characteristic curve C-statistic: 0.60 vs 0.59, p = 0.29). By multivariable analysis, the CSS combined with PCI history and hypertension were strong predictors for cardiac death and CSS, intra-aortic balloon pump support, diabetes, and successful PCI were independent predictors for MACE. In conclusion, compared with the anatomic SS, CSS was suitable in risk stratifying and predicting 2-year clinical outcome among ACS population.

Risk Stratification for Percutaneous Coronary Intervention

The Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score is a semiquantitative angiographic score developed to prospectively characterize the disease complexity of the coronary vasculature. With more than 50 validation studies, the SYNTAX score is the most-studied risk model in the setting of percutaneous coronary intervention. In this article, the evolutionary journey of the SYNTAX score is reviewed, with emphasis on its sequential modifications and adaptations, now culminating in the development and validation of the SYNTAX score II.

Potential Utility of the SYNTAX Score 2 in Patients Undergoing Left Main Angioplasty

Background

The revascularization strategy of the left main disease is determinant for clinical outcomes.

Objective

We sought to 1) validate and compare the performance of the SYNTAX Score 1 and 2 for predicting major cardiovascular events at 4 years in patients who underwent unprotected left main angioplasty and 2) evaluate the long-term outcome according to the SYNTAX score 2-recommended revascularization strategy.

Methods

We retrospectively studied 132 patients from a single-centre registry who underwent unprotected left main angioplasty between March 1999 and December 2010. Discrimination and calibration of both models were assessed by ROC curve analysis, calibration curves and the Hosmer-Lemeshow test.

Results

Total event rate was 26.5% at 4 years.The AUC for the SYNTAX Score 1 and SYNTAX Score 2 for percutaneous coronary intervention, was 0.61 (95% CI: 0.49-0.73) and 0.67 (95% CI: 0.57-0.78), respectively. Despite a good overall adjustment for both models, the SYNTAX Score 2 tended to underpredict risk. In the 47 patients (36%) who should have undergone surgery according to the SYNTAX Score 2, event rate was numerically higher (30% vs. 25%; p=0.54), and for those with a higher difference between the two SYNTAX Score 2 scores (Percutaneous coronary intervention vs. Coronary artery by-pass graft risk estimation greater than 5.7%), event rate was almost double (40% vs. 22%; p=0.2).

Conclusion

The SYNTAX Score 2 may allow a better and individualized risk stratification of patients who need revascularization of an unprotected left main coronary artery. Prospective studies are needed for further validation.

Improved correlation between carotid and coronary atherosclerosis SYNTAX score using automated ultrasound carotid bulb plaque IMT measurement

Described here is a detailed novel pilot study on whether the SYNTAX (Synergy between percutaneous coronary intervention with TAXUS and cardiac surgery) score, a measure of coronary artery disease complexity, could be better predicted with carotid intima-media thickness (cIMT) measures using automated IMT all along the common carotid and bulb plaque compared with manual IMT determined by sonographers. Three hundred seventy consecutive patients who underwent carotid ultrasound and coronary angiography were analyzed. SYNTAX score was determined from coronary angiograms by two experienced interventional cardiologists. Unlike most methods of cIMT measurement commonly used by sonographers, our method involves a computerized automated cIMT measurement all along the carotid artery that includes the bulb region and the region proximal to the bulb (under the class of AtheroEdge systems from AtheroPoint, Roseville, CA, USA). In this study, the correlation between automated cIMT that includes bulb plaque and SYNTAX score was found to be 0.467 (p < 0.0001), compared with 0.391 (p < 0.0001) for the correlation between the sonographer's IMT reading and SYNTAX score. The correlation between the automated cIMT and the sonographer's IMT was 0.882. When compared against the radiologist's manual tracings, automated cIMT system performance had a lumen-intima error of 0.007818 ± 0.0071 mm, media-adventitia error of 0.0179 ± 0.0125 mm and automated cIMT error of 0.0099 ± 0.00988 mm. The precision of automated cIMT against the manual radiologist's reading was 98.86%. This current automated algorithm revealed a significantly stronger correlation between cIMT and coronary SYNTAX score as compared with the sonographer's cIMT measurements with multiple cardiovascular risk factors. We benchmarked our correlation between the automated cIMT that includes bulb plaque and SYNTAX score against a previously published (Ikeda et al. 2013) AtheroEdgeLink (AtheroPoint) correlation between the automated cIMT that does not include bulb plaque and SYNTAX score and had an improvement of 44.58%. By sampling cIMT in the bulb region, the automated cIMT technique improves the degree of correlation between coronary artery disease lesion complexity and carotid atherosclerosis characteristics.

1,5-Anhydro-D-glucitol predicts coronary artery disease prevalence and complexity

BACKGROUND

The relationship between hemoglobin A1c (HbA1c) levels and coronary artery disease (CAD) has previously been confirmed. Serum 1,5-anhydro-D-glucitol (1,5-AG) levels are a useful clinical marker for short-term glycemic status that reflect glycemic excursions with greater sensitivity compared with HbA1c, specifically in the postprandial state. Postprandial hyperglycemia is an important CAD risk factor. Thus, the aim of this study was to compare HbA1c with 1,5-AG as a CAD predictor.

METHODS

The subjects consisted of 336 consecutive patients who underwent their first coronary angiography between July 2011 and March 2013. The relationship between CAD prevalence and HbA1c as well as CAD prevalence and 1,5-AG levels was evaluated. The correlation between CAD complexity and HbA1c or 1,5-AG was also assessed. CAD complexity was evaluated by the SYNTAX score.

RESULTS

CAD patients presented with significantly lower 1,5-AG and higher HbA1c values than patients without CAD (11.6 μg/ml [6.1, 19.1] vs. 17.6 μg/ml [11.9, 25.0], p<0.001, and 6.0% [5.6, 7.1] vs. 5.7% [5.4, 6.2], p<0.001, respectively) (median [25th, 75th percentiles]). According to logistic regression analysis, 1,5-AG was a predictor of CAD prevalence (odds ratio 0.94, 95% confidence interval 0.90-0.97). However, HbA1c levels did not present a predictive value for CAD. Levels of 1,5-AG and HbA1c were significantly correlated with SYNTAX scores (ρ=-0.27, p<0.001; and ρ=0.23, p<0.001, respectively).

CONCLUSIONS

The use of 1,5-AG, may be superior to HbA1c in predicting CAD prevalence. Both 1,5-AG and HbA1c correlate with CAD complexity.

Coronary artery bypass graft surgery versus percutaneous coronary intervention in patients with three-vessel disease and left main coronary disease: 5-year follow-up of the randomised, clinical SYNTAX trial

BACKGROUND

We report the 5-year results of the SYNTAX trial, which compared coronary artery bypass graft surgery (CABG) with percutaneous coronary intervention (PCI) for the treatment of patients with left main coronary disease or three-vessel disease, to confirm findings at 1 and 3 years.

METHODS

The randomised, clinical SYNTAX trial with nested registries took place in 85 centres in the USA and Europe. A cardiac surgeon and interventional cardiologist at each centre assessed consecutive patients with de-novo three-vessel disease or left main coronary disease to determine suitability for study treatments. Eligible patients suitable for either treatment were randomly assigned (1:1) by an interactive voice response system to either PCI with a first-generation paclitaxel-eluting stent or to CABG. Patients suitable for only one treatment option were entered into either the PCI-only or CABG-only registries. We analysed a composite rate of major adverse cardiac and cerebrovascular events (MACCE) at 5-year follow-up by Kaplan-Meier analysis on an intention-to-treat basis. This study is registered with ClinicalTrials.gov, number NCT00114972.

FINDINGS

1800 patients were randomly assigned to CABG (n=897) or PCI (n=903). More patients who were assigned to CABG withdrew consent than did those assigned to PCI (50 vs 11). After 5 years' follow-up, Kaplan-Meier estimates of MACCE were 26·9% in the CABG group and 37·3% in the PCI group (p<0·0001). Estimates of myocardial infarction (3·8% in the CABG group vs 9·7% in the PCI group; p<0·0001) and repeat revascularisation (13·7%vs 25·9%; p<0·0001) were significantly increased with PCI versus CABG. All-cause death (11·4% in the CABG group vs 13·9% in the PCI group; p=0·10) and stroke (3·7%vs 2·4%; p=0·09) were not significantly different between groups. 28·6% of patients in the CABG group with low SYNTAX scores had MACCE versus 32·1% of patients in the PCI group (p=0·43) and 31·0% in the CABG group with left main coronary disease had MACCE versus 36·9% in the PCI group (p=0·12); however, in patients with intermediate or high SYNTAX scores, MACCE was significantly increased with PCI (intermediate score, 25·8% of the CABG group vs 36·0% of the PCI group; p=0·008; high score, 26·8%vs 44·0%; p<0·0001).

INTERPRETATION

CABG should remain the standard of care for patients with complex lesions (high or intermediate SYNTAX scores). For patients with less complex disease (low SYNTAX scores) or left main coronary disease (low or intermediate SYNTAX scores), PCI is an acceptable alternative. All patients with complex multivessel coronary artery disease should be reviewed and discussed by both a cardiac surgeon and interventional cardiologist to reach consensus on optimum treatment.

FUNDING

Boston Scientific.