Artificial intelligence-enabled comprehensive coronary phenotyping in patients with suspected CAD

Introduction

The capabilities of artificial intelligence (AI) are rapidly progressing and the research community is getting increasingly interested in its possibilities. AI algorithms are able to work continuously and at high speed, reducing human workload and saving time that physicians can spend on more complex data or rarer cases. However, many clinical AI applications are currently only used in a research setting and lack proper testing and validation.

Objectives

This study aimed to determine the accuracy and performance of a novel AI-based software tool for CCTA analysis compared to conventional expert evaluation.

Methods

We evaluated 100 CCTA exams from a cohort of symptomatic patients with mild-to-moderately abnormal non-invasive ischemia test. Stenosis severity assessed by AI-based analysis (automatic evaluation, AEv) was compared with a level III expert CCTA interpretation (manual evaluation, MEv). AI-based analysis reported exact % stenosis and obstructive CAD was considered if maximal stenosis was ≥50%. Plaque phenotype was also estimated using AI algorithms.

Results

The study cohort was as follows: 52% male, mean age 68±10 years. The prevalence of hypertension, dyslipidemia and diabetes was 77%, 81% and 23%, respectively, and 10-year cardiovascular risk was 19±10% as predicted by Framingham risk score. Typical angina was present in 33%, of which 67% had a Canadian Cardiovascular Society angina grade ≥2.

Overall prevalence of obstructive CAD determined by MEv and AEv was 25% and 21%, respectively, with a significant association between both assessments (p<0.001). When compared to MEv as reference, AEv method performed with a sensitivity, specificity, positive and negative predictive values of 0.56, 0.91, 0.58 and 0.86, respectively. Area under the curve was 0.871 (p<0.001) demonstrating high accuracy.

AEv atherosclerosis quantification revealed significant differences between patients with and without obstructive CAD according to MEv: median total plaque volume (569 vs 115 mm3, p<0.001), calcified plaque volume (297 vs 19 mm3, p<0.001), non-calcified plaque volume (235 vs 71 mm, p<0.001), low-density non-calcified plaque volume (2.8 vs 1.0 mm3, p=0.023) and percent atheroma volume (16.1 vs 3.8 mm3, p<0.001).

Conclusion

In patients with suspected CAD and mild-to-moderately abnormal ischemia tests, a diagnostic strategy using AEv as a gatekeeper is effective, providing a quantitative stenosis evaluation with similar diagnostic performance for obstructive CAD when compared to MEv. AI-enabled approach additionally allows a fully automated quantification of coronary plaque volumes and composition, which would further enhance risk stratification.

Funding Acknowledgement

Type of funding sources: None.

Influence of age on the diagnostic value of coronary artery calcium score for ruling out coronary stenosis in symptomatic patients

Background

The 2021 Guideline for the Evaluation of Chest Pain supports the use of coronary artery calcium (CAC) score as a reasonable first-line test to identify patients with a low likelihood of obstructive coronary artery disease (CAD) who may not require additional testing (class IIa, LOE B). However, a recent study from a large cohort of Northern European patients raised concerns about the added diagnostic value of CAC=0 in younger patients. The aim of this study was to assess the influence of age on the value of CAC=0 in symptomatic patients undergoing coronary computed tomography angiography (CCTA).

Methods

We conducted a two-center cross-sectional study assessing symptomatic patients with suspected CAD who underwent CAC score and CCTA. Key exclusion criteria were age <30 years, known CAD, suspected acute coronary syndrome, or symptoms other than chest pain or dyspnea. Pretest probability of obstructive CAD was calculated based on age, sex and symptom typicality, according to the guideline-recommended method. Obstructive CAD was defined as any luminal stenosis ≥50% on CCTA. The diagnostic likelihood ratios and negative predictive values (NPV) were used to assess the diagnostic value of a CAC score of 0 to rule out obstructive CAD.

Results

A total of 2043 patients (mean age 60±11 years, 60% women) of whom 990 (48.5%) had a CAC score of 0 were included in the analysis. Symptom characteristics were: 38% non-anginal chest pain, 30% atypical angina, 19% dyspnea, and 13% typical chest pain. Overall, the prevalence of obstructive CAD was 12.8% (n=262). Pretest probability of obstructive CAD increased progressively with age, from 6.0% in patients young than 50 years to 20.7% in those 70 years or older. Contrariwise, the prevalence of patients with a CAC score = 0 decreased from 77% in patients younger than 50 years, to 26% in those who where 70 years or older.

The added diagnostic value of a CAC score = 0 was lower in younger patients, with negative likelihood ratios ranging from 0.36 (64% decrease in the likelihood of CAD) in patients younger than 50 years, to 0.09 and 0.10 (∼90% decrease in the likelihood of CAD) in those aged 60–69 years and 70 years or older, respectively – Figure 1.

Despite this, the prevalence of obstructive CAD among patients with a CAC score = 0 was low across all age groups: 2.4% (i.e., NPV = 97.6%) in those younger than 50 years, 3.0% (NPV = 97.0%) among those aged 50–59 years, 1.5% (NPV = 98.5%) in patients between 60 and 69 years, and 2.0% (NPV = 98.0%) among those 70 years or older.

Conclusions

In a cohort of symptomatic patients undergoing CCTA for suspected CAD, the added diagnostic value of a CAC score of zero decreases significantly at younger ages. However, this “diminishing return” of CAC in younger patients if offset by their lower pretest probabilities, yielding high negative predictive values independently of age.

Funding Acknowledgement

Type of funding sources: None.

Implications of the North American 2021 Chest Pain guidelines in the diagnostic approach to patients with stable chest pain and low pretest probability of obstructive coronary artery disease

Background

The North American 2021 Chest Pain Guidelines recommend not testing stable patients with low pretest likelihood of obstructive coronary artery disease (CAD), defined as pretest probability <15% using contemporary models (Class I recommendation). In selected cases among this subset of patients, coronary artery calcium (CAC) score is considered a “reasonable first-line test” (Class IIa). Despite some supporting evidence, the clinical implications of a widespread adoption of these recommendations remain unclear.

The purpose of this study was to assess the results of three different testing strategies for patients with pretest probability <15%: A) defer testing; B) perform CAC score and withhold further testing if = 0, and proceed to coronary CT angiography (CCTA) if >0; C) perform CCTA in all.

Methods

We conducted a two-center cross-sectional study assessing symptomatic patients with suspected CAD who underwent CAC score and CCTA. Patients with known CAD, suspected acute coronary syndrome, or symptoms other than chest pain or dyspnea were excluded. Pretest probability of obstructive CAD was calculated based on age, sex and symptom typicality. Obstructive CAD was defined as any luminal stenosis ≥50% on CCTA.

Results

A total of 2259 patients were screened, of which 1385 (61.3%) had pretest probability <15% and were included in the analysis (mean age 57±11 years, 79% women). Symptom characteristics were: 48% non-anginal chest pain, 26% atypical angina, 21% dyspnea, and 5% typical chest pain. Overall, the prevalence of obstructive CAD was 10.3% (n=142). In the 786 patients (56.6%) with a CAC score of 0, 8.5% (n=67) had some degree of CAD [1.9% (n=15) obstructive, and 6.6% (n=52) nonobstructive]. Among those with CAC >0 (n=599), 21.2% (n=127) had obstructive CAD. The results that would be reached with each of the 3 diagnostic strategies are presented in Figure 1. The number of patients needed to scan with strategy B (CAC as gatekeeper) vs. A (no testing) to identify one patient with obstructive CAD was 11, whereas the number needed to scan with strategy C (CCTA for all) vs. strategy B was 91.

Conclusions

Not testing patients with suspected CAD and pretest likelihood <15% would lead to missing obstructive CAD in 1 out of 10 patients. Using CAC as a gatekeeper in this subgroup would decrease the use of CCTA by more than 50%, at the cost of missing obstructive CAD in 1 out of 100 patients. These findings may be used to inform decisions on testing, which will ultimately depend on how much diagnostic uncertainty and missed diagnoses patients and their physicians are willing to accept.

Funding Acknowledgement

Type of funding sources: None.

Analysis of opiates in urine using microextraction by packed sorbent and gas Chromatography- Tandem mass spectrometry

Opiates recreational consumption has always been a concern in society, public health, and in clinical toxicology analysis. The aim of this study was to develop and fully validate an analytical method, which was simple and rapid for the determination of tramadol, codeine, morphine, 6- acetylcodeine, 6-monoacetylmorphine and fentanyl using gas chromatography coupled to tandem mass spectrometry. The procedure includes the use of microextraction by packed sorbent for sample clean-up. A mixed mode sorbent was used, allowing the minimal use of solvents. The method was validated in urine samples, with the ability to detect and quantify all analytes with satisfactory linearity (in the range of 1 - 1000 ng/mL for all analytes, except for fentanyl (10-1000 ng/mL)). Extraction efficiency varied from 17 to 107%, which did not impair sensitivity, taking into account the low LLOQs obtained (1 ng/ mL for all analytes; and 10 ng/mL for fentanyl). The developed procedure proved to be fast, selective, and accurate for use in routine analysis, with a low volume of sample (250 µL).

Electrocardiographic imaging a valid tool or an inaccurate toy?

Funding Acknowledgements

Type of funding sources: Private hospital(s). Main funding source(s): Learning Health

Background and aim

Electrocardiographic imaging (ECGI) is capable of performing an activation map with a single beat. However, previous studies using the epicardial-only system, have suggested a bad accuracy for the assessment of the epicardial breakthrough. Recent systems using endo-epicardial analysis have shown promising results. The aim of this study was to assess the accuracy and reproducibility of two endo-epicardial ECGI systems using different cardiac sources one based on the extracellular-potential, and the other on the equivalent double layer model, respectively the AMYCARD (EP Solutions SA, Switzerland) and VIVO (Catheter Precision, NJ USA) systems.

Methods

We studied 11 consecutive patients referred for ablation of frequent idiopathic premature ventricular contractions at our center that had an ECGI performed using both systems on the same day. The AMYCARD system uses a dense array of body-surface electrocardiograms with up to 224 leads and VIVO uses just the 12-leads ECG. Both systems use a patient-specific heart torso geometry obtained with a CT-scan or cardiac magnetic resonance. The localisation of the PVCs based on ECGI was done using a segmental model with 22 segments on the left ventricle, to include the classical 17 segment model plus the aortic cusps and the papillary muscles, and 12 segments on the right ventricle including 4 on the right ventricular outflow tract (RVOT): (anterior, lateral, right septum and left septum). A perfect match was defined as a predicted location within the same anatomic segment, whereas a near match as a predicted location within the same segment or a contiguous one.

Results

The median (Q1-Q3) number of leads used for the AMYCARD was 131 (118-144). Seven patients underwent ablation and in 4 ablation is pending. The predicted locations and the ablation site are depicted on the Table. We found a perfect match between both systems in 73% (Figure) and near match in 91% of cases. In patients that underwent ablation the systems localised the site of origin of the PVCs within the same segment or the contiguous segment in all patients with VIVO and in six out of seven with AMYCARD.

Conclusions

ECGI is an accurate diagnostic tool with reproducible results regardless the cardiac source used for analysis.

Assessment of activation duration across the right ventricular outflow tract in patients with premature ventricular contractions using noninvasive electrocardiographic mapping: a validation study

Funding Acknowledgements

Type of funding sources: Private hospital(s). Main funding source(s): Learning Health

Introduction

Previous studies have reported that wavefront propagation speed across the right ventricular outflow tract (RVOT) can distinguish premature ventricular contractions (PVCs) with a RVOT origin from PVCs with a left ventricular outflow tract (LVOT) origin.

Aim

Validate the non-invasive electrocardiographic mapping (ECGI) for assessment of RVOT activation duration (AD) during PVCs and assess its value as a predictor of the origin of the PVCs.

Methods

We studied 18 consecutive patients, 8 males, median age 55 (35-63) years that underwent ablation of frequent (> 10.000 per 24 h) idiopathic PVCs with inferior axis, that had and an ECGI performed before ablation and the RVOT mapped in PVC. The ECGI was performed with the Amycard system, and invasive mapping was performed with the Carto or Ensite system. Isochronal activation maps of the RVOT in PVC were obtained with the activation direction method (ADM) of the ECGI, and with the Carto and Ensite systems. Total RVOT AD was measured as the time interval between the earliest and the latest activated region. Agreement between the two methods was performed using a Bland-Altman plot and linear regression . The cutoff value of AD to predict PVC origin was calculated with ROC curve.

Results

PVCs originated from the RVOT in 11 (61%) patients. The median (Q1-Q3) RVOT AD measured with ECGI was 54 (39-68) ms and with invasive map 57 (36-70) ms. The agreement between both methods was good with an R2 of 0.747, p<0.0001. Figure displays the Bland-Altman plot (panel A), the linear regression plot (panel B). and two examples of the ECGI isochronal map (panel C). The AD was significantly higher in PVCs from the RVOT vs LVOT, both with ECGI and Carto, respectively 62 (58-73) vs 37 (33-40) ms, p<0.0001 and 68 (60-75) vs 34 (30-40) ms, p<0.0001. The cutoff value of 43 ms for AD measured with ECGI, predicted the origin of the PVCs with a sensitivity and specificity of 100%.

Conclusions

We found good agreement between ECGI and Carto. The AD obtained with ECGI was accurate to predict the origin of the PVCs.

An Update on the Implications of New Psychoactive Substances in Public Health

The emergence of new psychoactive substances has earned a great deal of attention, and several reports of acute poisoning and deaths have been issued involving, for instance, synthetic opiates. In recent years, there have been profound alterations in the legislation concerning consumption, marketing, and synthesis of these compounds; rapid alert systems have also been subject to changes, and new substances and new markets, mainly through the internet, have appeared. Their effects and how they originate in consumers are still mostly unknown, primarily in what concerns chronic toxicity. This review intends to provide a detailed description of these substances from the point of view of consumption, toxicokinetics, and health consequences, including case reports on intoxications in order to help researchers and public health agents working daily in this area.

Optimization and validation of a procedure using the dried saliva spots approach for the determination of tobacco markers in oral fluid

Exposure to tobacco smoke is one of the most common causes of premature death worldwide and is the cause of 8 million deaths annually. We have developed, optimized, and validated a procedure for the detection of nicotine, cotinine and trans-3-hydroxycotinine (biomarkers of tobacco exposure) in oral fluid using the dried saliva spots sampling approach and gas chromatography coupled to tandem mass spectrometry, thus allowing the distinction between active and passive smokers. For optimization, four parameters were evaluated, namely extraction solvent, extraction solvent volume, extraction time and spots drying time. During method validation, the parameters selectivity, linearity, precision and accuracy, recovery, stability, and dilution factor were assessed. Linearity was obtained for all target analytes in the concentration range of 10-200 ng/mL allowing the quantification of compounds up to 1000 ng/mL considering the dilution factor. The method recoveries ranged from 29.2% to 43.30% for nicotine, 66.60-89.10% for cotinine and 80.30-92.80% for trans-3-hydroxycotinine, while achieving intra-day, inter-day and intermediate precision and accuracy values never higher than 10.37% and ±6.62% respectively for all compounds. The herein described analytical method is the first to allow the determination of tobacco biomarkers in oral fluid using dried saliva spots, which is considered a sensitive, simple and low-cost alternative to conventional methods.

Epicardial fat volume improves prediction of adverse clinical events

Funding Acknowledgements

Type of funding sources: None.

Introduction

Recent studies have demonstrated the potential of epicardial fat volume (EFV) to predict obstructive coronary artery disease (CAD), however its impact in clinical outcomes remains elusive.

Objectives

To assess the association between EFV and demo­graphic and morphometric data, coronary atherosclerotic burden and adverse events in a population of patients (pts) referred for coronary computed tomography angiography (CTA).

­Methods: Retrospective analysis of pts without known CAD referred for coronary CTA in a single tertiary care centre. A standardized protocol for quantification of EFV, thoracic fat volume (TFV), coronary artery calcification (CAC) and coronary angiography was performed. Endpoint was composite of cardiovascular death, nonfatal myocardial infarction and urgent hospitalization leading to revascularization at 12 months.

Results

72 pts were included, 58% male, mean age 67 ± 9 years. The prevalence of hypertension, dyslipidemia and diabetes was 75%, 82% and 24%, respectively. Median EFV was 101 (68) ml and total TFV 1504 (694) ml. EFV was directly related with age (rs= 0.42, p <0.001), male sex (135 ± 50 vs 78 ± 30, p <0.001), body mass index (rs= 0.32, p= 0.008) and TFV (rs= 0.27, p= 0.025). A positive correlation with CAC (rs= 0.47, p <0.001) and a significant association with CAD (116 ± 50 vs 90 ± 37, p= 0.029) and obstructive CAD (141 ± 60 vs 97 ± 39, p= 0.031) were demonstrated. Composite endpoint was observed in 13 pts (18%). After adjusting for all considered confounders, EFV remained an independent predictor of adverse events (OR: 1.015, 95%CI: 1.003-1.027, p= 0.041). ROC analysis of EFV (AUC 0.751, p = 0.005) allowed to estimate that EFV >124 ml had a sensibility and specificity to predict clinical outcomes of 69% and 71%, respectively.

Conclusion

EFV positively relates to coronary atherosclerotic burden. This study also advocates that EFV may improve risk stratification for clinical outcomes. Larger studies are required to evaluate these results. Abstract Figure 1

Quantification of epicardial fat with cardiac CT and association with cardiovascular risk factors and obstructive coronary disease

Introduction

Recent studies advocate epicardial fat (EF) as a biologically active organ that influence coronary atherosclerosis development through endocrine and paracrine pathways. We aim to study the relations between EF, thoracic adipose tissue (TAT), cardiovascular risk factors (CRF) and obstructive coronary disease (OCD).

Methods

Retrospective analysis of patients (pts) referred to 64-multislice cardiac computed tomography (CT) in one center. The authors underwent a standardized protocol for quantification of EAT, TAT (subcutaneous and visceral), abdominal visceral fat, coronary calcium score and angiography.

Results

Total of 178 pts: male 99 (56%), mean age 65.9±12.9 years. Indications for performing CT were coronary disease (76%), valvular heart disease (15%), atrial fibrillation (6%) and congenital heart disease (2%). Regarding CRF, EF was only significant higher in patients with diabetes (115±60 vs 95±47, p=0.018), in male gender (114±60 vs 91±42, p=0.04) and was linear correlated with age (p=0.004). The authors also found that EF volume is significant higher in patients with typical angina (p=0.02) and with coronary atherosclerosis: non-obstructive (p=0.0049) and OCD (p=0.001) – Graphic 1. ROC analysis of EF (AUC 0.659, p=0.0039) and EF/TAT relation (AUC 0.704, p=0.003) allowed to estimate that EF>100 ml and EF/TAT >0.06 had a sensibility to predict OCD of 53% and 58%, respectively, and specificity of 66% and 60%. We did not find a correlation between EF, EF/TAT or TAT and coronary calcium score.

Conclusion

EF is higher in patients with diabetes and coronary atherosclerosis. EF and EF/TAT relation had moderate sensibility and specificity to predict OCD, irrespective of calcium score. EF and EF/TAT are promising atherosclerotic markers that could be routinely use in the near future.

Funding Acknowledgement

Type of funding sources: None.

Anomalous origin of the right coronary artery with interarterial course: red flag or innocent bystander?

Aims

Anomalous origin of the right coronary artery from the opposite sinus (right-ACAOS) with interarterial course (IAC) has been associated with increased risk of sudden cardiac death (SCD). Widespread use of coronary computed tomography angiography (CCTA) has led to increasing recognition of this condition, even among healthy individuals. Our study sought to examine the prevalence, anatomical characteristics and outcomes of right-ACAOS with IAC in patients undergoing CCTA for suspected coronary artery disease (CAD).

Methods and results

We conducted a retrospective analysis of consecutive patients referred for CCTA at one tertiary hospital from January 2012 to December 2020. Right-ACAOS with IAC patients were analyzed for cardiac symptoms and long-term occurrence of first MACE (SCD, non-fatal myocardial infarction (MI) or revascularization of the anomalous vessel). CCTAs were reviewed for anatomical high-risk features and concomitant CAD. Among 10928 patients referred for CCTA, 28 patients with right-ACAOS with IAC were identified. Mean age was 55±17 years, 64% were male and 11 (39.3%) presented with stable cardiac symptoms. Most patients had at least one high risk anatomical feature. During follow-up, there were no CV deaths or aborted SCD episodes and only 1 patient underwent surgical revascularization of the anomalous vessel.

Conclusion

Right-ACAOS with IAC is an uncommon finding (prevalence of 0.26%). In a contemporary population of predominantly asymptomatic patients who survived this condition well into adulthood, most patients were managed conservatively with a low event rate. Additional studies are needed to support medical follow-up as the preferred option in this setting.

Funding Acknowledgement

Type of funding sources: None.

Incorporating coronary calcification into pretest assessment of the likelihood of coronary artery disease: validation and recalibration of a new diagnostic tool

Background

A new clinical tool was recently proposed to improve the estimation of pre-test probability of obstructive coronary artery disease (CAD) by incorporating coronary artery calcium score (CACS) with clinical risk factors. This new model (Clinical+CACS) showed improved prediction when compared to the method recommended by the 2019 ESC guidelines on chronic coronary syndromes, but was never tested or adjusted for use in our population. The aim of this study was to assess the performance of this new method in a Portuguese cohort of symptomatic patients referred for coronary computed tomography angiography (CCTA), and to recalibrate it if necessary.

Methods

We conducted a two-center cross-sectional study assessing symptomatic patients who underwent CCTA for suspected CAD. Key exclusion criteria were age <30 years, known CAD, suspected acute coronary syndrome, or symptoms other than chest pain or dyspnea. Obstructive CAD was defined as any luminal stenosis ≥50% on CCTA. The Clinical+CACS prediction model was assessed for discrimination and calibration. A logistical recalibration of the model was conducted in a random sample of 50% of the patients and subsequently validated in the other half.

Results

A total of 1910 patients (mean age 60±11 years, 60% women) were included in the analysis. Symptom characteristics were: 39% non-anginal chest pain, 30% atypical angina, 19% dyspnea and 12% typical angina. The observed prevalence of obstructive CAD was 12.9% (n=247). Patients with obstructive CAD were more often male, were significantly older, had higher prevalence of typical angina and cardiovascular risk factors, and higher CACS values. The new Clinical+CACS tool showed greater discriminative power than the ESC 2019 prediction model, with a C-statistic of 0.83 (CI 95% 0.81–0.86) versus 0.67 (CI 95% 0.64–0.71), respectively (p-value for comparison <0.001). Before recalibration, the Clinical+CACS model underestimated the likelihood of CAD in our population across all quartiles of pretest probability (mean relative underestimation of 49%), which was subsequently corrected by the recalibration procedure - Figure.

Conclusions

In a Portuguese cohort of symptomatic patients undergoing CCTA for suspected CAD, the new Clinical+CACS model showed better discrimination power than the 2019 ESC method. The underestimation of the Clinical+CACS model was corrected by recalibrating it for our population. This new tool might prove useful for guiding decisions on the need for further testing.

Funding Acknowledgement

Type of funding sources: None.

Anomalous origin of the right coronary artery with interarterial course: red flag or innocent bystander?

Funding Acknowledgements

Type of funding sources: None.

Background

Anomalous origin of the right coronary artery (right ACAOS) with interarterial course (IAC) has been associated with increased risk of sudden cardiac death (SCD). Widespread use of coronary computed tomographic angiography (CCTA) has led to increasing recognition of this condition, even among healthy individuals. This study sought to examine the prevalence, anatomical characteristics and outcomes of right ACAOS with IAC in patients undergoing CCTA for all-indications.

Methods

We conducted a retrospective analysis of consecutive patients referred for CCTA at one tertiary hospital between January 2012 and December 2020. Right ACAOS patients with IAC were analyzed for cardiac symptoms (anginal chest pain, syncope, aborted SCD) and long-term outcomes were evaluated for myocardial infarction, ischemic test results, revascularization procedures and all-cause or cardiovascular (CV) mortality. CCTAs were reviewed for proposed high-risk features (ie., take-off angle, length and severity of proximal narrowing, intramural course, interarterial length) and concomitant coronary artery disease (CAD). Association between high-risk features was analyzed. Long-term outcomes were evaluated.

Results

Among 10,928 patients referred for CCTA during the study period, we identified 28 patients (0.3% prevalence) with right ACAOS and IAC. Mean age was 55 ± 17 years, 64% were male and 11 (39.3%) presented cardiac symptoms. During a median follow-up of 44.1 ± 31.8 months, there were no CV deaths and only 1 patient (3.65%) underwent surgical revascularization. Baseline characteristics and CCTA findings are presented in figure 1.

Conclusion

Right ACAOS and IAC is an uncommon finding, with an observed prevalence of 0.3%. CCTA provides excellent anatomical characterization of anomalous vessels, including suggested high-risk features. In a population of asymptomatic patients who survived this condition well into adulthood, the risk of events was very low and medical follow up might be a reasonable option.

Incorporating coronary calcification into pretest assessment of the likelihood of coronary artery disease: validation and recalibration of a new diagnostic tool

Funding Acknowledgements

Type of funding sources: None.

Background

A new clinical tool was recently proposed to improve the estimation of pre-test probability of obstructive coronary artery disease (CAD) by incorporating coronary artery calcium score (CACS) with clinical risk factors. This new model (Clinical + CACS) showed improved prediction when compared to the method recommended by the 2019 ESC guidelines on chronic coronary syndromes, but was never tested or adjusted for use in our population. The aim of this study was to assess the performance of this new method in a Portuguese cohort of symptomatic patients referred for coronary computed tomography angiography (CCTA), and to recalibrate it if necessary.

Methods

We conducted a two-center cross-sectional study assessing symptomatic patients who underwent CCTA for suspected CAD. Key exclusion criteria were age < 30 years, known CAD, suspected acute coronary syndrome, or symptoms other than chest pain or dyspnea. Obstructive CAD was defined as any luminal stenosis ≥50% on CCTA. The Clinical + CACS prediction model was assessed for discrimination and calibration. A logistical recalibration of the model was conducted in a random sample of 50% of the patients and subsequently validated in the other half.

Results

A total of 1910 patients (mean age 60 ± 11 years, 60% women) were included in the analysis. Symptom characteristics were: 39% non-anginal chest pain, 30% atypical angina, 19% dyspnea and 12% typical angina. The observed prevalence of obstructive CAD was 12.9% (n = 247). Patients with obstructive CAD were more often male, were significantly older, had higher prevalence of typical angina and cardiovascular risk factors, and higher CACS values. The new Clinical + CACS tool showed greater discriminative power than the ESC 2019 prediction model, with a C-statistic of 0.83 (CI 95% 0.81-0.86) versus 0.67 (CI 95% 0.64-0.71), respectively (p-value for comparison < 0.001). Before recalibration, the Clinical + CACS model underestimated the likelihood of CAD in our population across all quartiles of pretest probability (mean relative underestimation of 49%), which was subsequently corrected by the recalibration procedure - Figure.

Conclusions

In a Portuguese cohort of symptomatic patients undergoing CCTA for suspected CAD, the new Clinical + CACS model showed better discrimination power than the 2019 ESC method. The underestimation of the Clinical + CACS model was corrected by recalibrating it for our population. This new tool might prove useful for guiding decisions on the need for further testing.

Three-dimensional late gadolinium enhancement increases the diagnostic yield of cardiovascular magnetic resonance to detect low voltage in the right ventricular outflow tract

Funding Acknowledgements

Type of funding sources: None.

Background

Cardiac magnetic resonance (CMR) using late gadolinium enhancement (LGE) fails to detect scar tissue in patients with electroanatomical abnormalities and biopsy-proven structural heart disease. It has shown conflicting data regarding existence of structural abnormalities in patients with idiopathic premature ventricular contractions (PVCs) from the right ventricular outflow tract (RVOT). Three- dimensional (3D) LGE enables high-spatial resolution more appropriate to the thin-walled right ventricle than two-dimensional (2D) LGE.

Objective

Our aim was to evaluate if the use of 3D-LGE would improve the performance of CMR to detect low voltage areas in the RVOT of patients with PVCs.

Methods

Since May 2020 we performed 3D-LGE CMR in 11 consecutive patients that underwent ablation of frequent PVCs. A control group of 11 consecutive patients that underwent catheter ablation by the same operator and had a 2D-LGE CMR performed before ablation was also studied. All patients had normal 2D-LGE CMR. A 3D electroanatomical bipolar voltage map of the RVOT was performed in sinus rhythm (0.5 mV-1.5 mV colour display). Areas with electrograms <1.5 mV represented the LVA. The area adjacent to the pulmonary valve usually displays voltage between 0.5 and 1.5 mV and is classified as transitional-voltage zone. Presence of LVAs outside this transitional-voltage zone were estimated.  We compared the accuracy of CMR for detecting LVA in the two groups: 3D LGE and 2D LGE.

Results

The median number of points used for the voltage map was 344 (242-450). 18 patients (82%) displayed LVAs. The site of origin of the PVCs was the RVOT in 17 patients and the left ventricular outflow tract (LVOT) in 5. Comparison between groups is displayed in the table.  2D LGE CMR failed to demonstrate abnormalities of the RVOT in any of the patients that presented with LVAs. 3D CMR showed presence of fibrosis (Figure) in 3 out of 9 patients with LVAs (33%).

Conclusion

CMR using 3-D LGE techniques showed an increased power to diagnose structural abnormalities. This technique may be a better choice in initial stages of RVOT disease. All sampleN = 223D-LGE CMRN = 112D-LGE CMRN = 11p-valueAge in years, median (Q1-Q3)47 (35-68)62 (34-55)42 (34-55)0.243Male gender, n (%)8 (36)3 (27)5 (46)0.330PVCs RVOT/LVOT17/59/28/30.500Nº points in the map, median (Q1-Q3)344 (242-450)350 (259-450)300 (158-345)0.076Low voltage areas, n (%)18 (82)9 (82)9 (82)0.707Abstract Figure.

Recent Developments in the Determination of Biomarkers of Tobacco Smoke Exposure in Biological Specimens: A Review

Environmental tobacco smoke exposure (ETS) and smoking have been described as the most prevalent factors in the development of certain diseases worldwide. According to the World Health Organization, more than 8 million people die every year due to exposure to tobacco, around 7 million due to direct ETS and the remaining due to exposure to second-hand smoke. Both active and second-hand exposure can be measured and controlled using specific biomarkers of tobacco and its derivatives, allowing the development of more efficient public health policies. Exposure to these compounds can be measured using different methods (involving for instance liquid- or gas-chromatographic procedures) in a wide range of biological specimens to estimate the type and degree of tobacco exposure. In recent years, a lot of research has been carried out using different extraction methods and different analytical equipment; this way, liquid-liquid extraction, solid-phase extraction or even miniaturized procedures have been used, followed by chromatographic analysis coupled mainly to mass spectrometric detection. Through this type of methodologies, second-hand smokers can be distinguished from active smokers, and this is also valid for e-cigarettes and vapers, among others, using their specific biomarkers. This review will focus on recent developments in the determination of tobacco smoke biomarkers, including nicotine and other tobacco alkaloids, specific nitrosamines, polycyclic aromatic hydrocarbons, etc. The methods for their detection will be discussed in detail, as well as the potential use of threshold values to distinguish between types of exposure.

Predictors of atrial fibrillation occurrence in patients with hypertrophic cardiomyopathy

Introduction

Patients with hypertrophic cardiomyopathy (HCM) are at increased risk of dysrhythmias, especially atrial fibrillation (AF).

Purpose

The aim of this study was to evaluate the incidence of AF in HCM patients (P) and to determine predictors of AF.

Methods

Retrospective analysis of HCM P at a single tertiary center. Baseline clinical, echocardiographic and cardiovascular magnetic resonance (CMR) characteristics were collected. On follow up AF was identified by electrocardiogram and/or 24 hours Holter monitoring.

Results

61P (59% male) were included, with a mean age of 58±2 years. 27.9% had angina (all of them CCS 2), 34.4% were in NYHA II and 14.8% in NYHA III, 8.2% had syncope and 39.3% had palpitations. A family history of sudden cardiac death (SCD) or cardiomyopathy was present in 40.4% of the cases. The mean HCM risk SCD score was 3.35±0.28%. On echocardiography left atrium (LA) diameter was 44.86±0.87mm, LA volume (LAvol) was 89.97±5.39mL (indexed LAvol 46.05±2.55mL/m2), interventricular septum (IVS) was 16.83±0.663mm, left ventricle (LV) mass was 290.94±13.897g and maximum wall thickness (MWT) was 20.59±0.596mm. 77% P had LA enlargement. 88.5%P had late gadolinium enhancement (LGE) in CMR with a median number of 5±7 segments involved. AF developed in 23P (37.7%), with a mean age of 58±3 years. Predictors of AF development were NYHA III (p=0.007), risk score (p=0.007), LA diameter (p=0.007), LAvol (p=0.005) and indexed LAvol (p=0.002), MWT (p=0.0015), LGE in more than 5 segments (p=0.029) and LGE in the inferior basal and inferior median IVS (p=0.033 and p=0.042). The only independent predictor was LAvol (p=0.0012), with an area under the curve of 0.755 and a cut off of 85.9mL being the best predictor (p=0.004). Combining LAvol >85.9mL with LGE involving >5 segments and LAvol >85.9mL with LGE in inferior basal IVS (IBIVS) a statistically significant difference between groups was achieved (p=0.009 in the combined predictor LAvol + LGE >5 segments and p=0.002 in the combined predictor LAvol + LGE in IBIVS) (figure 1 and figure 2). In a multivariable analysis including these 2 combined predictors and LAvol alone the only independent predictor was the combination of LAvol + IBIVS involvement.

Conclusion

AF is frequent in patients with HCM and develops in younger ages than in general population. NYHA III, risk score, LA diameter, LAvol, MWT, LGE >5 segments and LGE in IBIVS and in IMIVS were predictors of AF, with LAvol being the independent predictor. The combination of LAvol with LGE >5 segments and LAvol with LGE in IBIVS presented stronger predictor value comparing with these characteristics alone.

Funding Acknowledgement

Type of funding source: None

Optimizing diagnosis of obstructive coronary artery disease by CT angiography: RCT's final results and 12-months follow-up

Aim

In patients (pts) with suspected coronary artery disease (CAD), computed tomographic angiography (CTA) may improve pt selection for invasive coronary angiography (ICA) as alternative to functional testing. However. the role of CTA in symptomatic pts after abnormal functional test (FT) is incompletely defined.

Methods and results

This randomized clinical trial conducted in single academic tertiary center selected 218 symptomatic pts with mild to moderately abnormal FT referred to ICA to receive either the originally intended ICA (n=103) or CTA (n=115). CTA interpretation and subsequent care decisions were made by the clinical team. Pts with high risk features on FT, previous acute coronary syndrome, previously documented CAD, chronic kidney disease (GFR<60ml/min/1.73m2) or persistent atrial fibrillation were excluded. The primary endpoint was the percentage of ICA with no significant obstructive CAD (no stenosis ≥50%) in each group. Diagnostic (DY) and revascularization (RY) yields of ICA in either group were also assessed. Pts were followed up for at least 1 year for the primary safety endpoint of all cause death/ nonfatal myocardial infarction/ stroke. Unplanned revascularization

(UP) and symptomatic status (SS) were also evaluated. Pts averaged 68±9 years of age, 60% were male, 29% were diabetic. Nuclear perfusion stress test was used in 33.9% in CTA group and 31.1% in control group (p=0.655). Mean post (functional) test probability of obstructive CAD was 34%. Overall prevalence of obstructive CAD was 32.1%. In the CTA group, ICA was cancelled by referring physicians in 83 of the pts (72.2%) after receiving CTA results. For those undergoing ICA, non-obstructive

CAD was found in 5 pts (15.6%) in the CTA-guided arm and 60 (58.3%) in the usual care arm (p<0.001 Mean cumulative radiation exposure related to diagnostic work up was similar in both groups (6±14 vs 5±14mSv, p=0.152). Both DY (84.4% vs 41.7, p<0.001) and RY (71.9% vs 38.8%, p=0.001) yields were significantly higher for CTA-guided ICA as compared to standard FT-guided ICA. The rate of the primary safety endpoint was similar between both groups (1.9% vs 0%, p=0.244), as well as the rates of UP (0.9% vs 0.9%, p=1.000) and SS (persistent angina: 29.6% vs 24.8%, p=0.425).

Conclusions

In pts with suspected CAD and mild to moderately abnormal ischemia test, a diagnostic strategy including CTA as gatekeeper is safe, effective and significantly improves diagnostic and revascularization yields of ICA.

Funding Acknowledgement

Type of funding source: None

P955Non-invasive mapping: what is the minimal number of electrodes needed to obtain a good spatial resolution of the activation map?

Introduction and aims

The 12-lead ECG is highly inaccurate for localization of the site of origin of supraventricular and ventricular arrhythmias.  Non-invasive mapping systems (ECGI) based on a high number of electrodes recording the electrical activity on the surface of the torso have already proven good accuracy for mapping different arrhythmic substrates. The aim of this study was to assess what is the minimal number of leads needed to obtain a precise mapping with the ECGI.

Methods

This study enrolled 14 patients (9 male, median age 50 (44-58) years) referred to our center for catheter ablation of premature ventricular contractions (PVC). Patients underwent pre-procedural ECGI using the epicardial and endocardial mapping system . This system uses the DICOM images from contrast computed tomography of the heart and up to 28 adhesive electrodes with 8 leads each, adding up to 224 body-surface leads. All patients underwent invasive electroanatomical mapping and ablation with the magnetic navigation system. We analysed the number of recording leads used to construct the non-invasive activation map of the PVCs and the accuracy and the spatial resolution of the map when comparing to the invasive map. We then reprocessed the exam, using progressively less leads until we only left the leads placed in the standard 12 lead ECG positions and evaluated the concordance with the invasive map as well as the spatial resolution. We considered an earliest activation site (EAS) area of 1 cm2 a good spatial resolution and using a ROC curve we calculated the minimal number of leads necessary to obtain a good spatial resolution.

Results

The median number of electrodes used for the initial map was 170 (138-177). Concordance between non-invasive and invasive site of origin occurred in 11 out of 14 patients. The results are presented in the Table. The minimal number of electrodes to have a good spatial resolution was 100. The area of EAS was significantly lower when using more than 100 leads, respectively 0.65 (0.5-1) cm2 versus 3 (1.6-5) cm2, p < 0.001.

Conclusions

The minimal number of leads to achieve a good spatial resolution was high.  Reducing the number of leads resulted in a significant decrease in spatial resolution and a lower concordance rate.

ECGI data Number of adhesive electrodes Median number of leads Amycard/Carto concordance Median area of EAS in the ECGI (cm2) Maximal nº electrodes 170 (138-177) 11/14 0.64 (0.5-0.9) 12 electrodes 76 (61-80) 11/14 1.6 (1.4-2.6) 6 electrodes (2 Ant, 2 Lat ,2 Post) 38 (32-44) 9/14 4.3 (3.2-5.4) 12 leads 12 0/14 - Ant anterior; Lat: lateral; Post: posterior; EAS: early activation site.

Abstract Figure. Area of EAS according to the N of leads

P5702Non-invasive epicardial and endocardial mapping in patients with idiopathic right ventricular outflow tract premature ventricular contractions: new insights into arrhythmia substrate

Background

It has been accepted for years that idiopathic premature ventricular contractions (PVCs) with origin in the right ventricular outflow tract (RVOT) are benign. They are thought to result from triggered activity and most studies do not describe abnormal findings during electroanatomical mapping

Dispersion of ventricular repolarization is associated with the susceptibility to ventricular arrhythmias and may indicate the presence of diseased myocardium. The activation recovery interval (ARI) has been used as a surrogate measure of ventricular action potential duration and refractory period.

Purpose

The aim of this study was to use the new non-invasive epicardial and endocardial mapping system (NEES) to study patients with RVOT PVCs in order to evaluate the ARI in the epicardium of RVOT during sinus rhythm (SR).

Methods

Non-invasive mapping was performed with the NEES, based on body surface electrocardiograms of a maximum of 224 electrodes and computed tomography imaging data. Unipolar electrograms were reconstructed on the epicardial and endocardial surfaces. Patients were excluded if they had structural heart disease, previous ablation or conduction abnormalities. ARI was defined as the interval between times of minimum derivative of the QRS and the maximum derivative of the T wave in the unipolar electrograms. We evaluated the ARI map in patients with RVOT PVCs and in a control group of patients without PVCs (Figure). We assessed the maximum value of ARI (Max ARI), the minimum value of ARI (Min ARI) and the difference between the Max ARI and the Min ARI (Diff ARI).

Results

We studied 8 patients with RVOT PVCs and 8 patients without PVCs.

The results are presented in the table.

Demographic and NEES data RVOT PVCs (n=8) Control (n=8) P value* Demographic data   Age in years, median (IQR) 53 (48–65) 59 (52–67) 0.536   Male gender, n (%) 4 (50) 6 (75) 0.608 NEES data   Max ARI in msec, median (IQR) 285 (236–331) 228 (197–298) 0.195   Min ARI in msec, median (IQR) 176 (138–192) 216 (185–255) 0.161   ARI diff in msec, median (IQR) 111 (83–147) 15 (4–34) <0.0001

NEES map

Conclusion

In this group of patients we found a significantly higher dispersion of the ARI measurements through the epicardium of the RVOT in patients with PVCs in comparison with patients without PVCs.

P6165Sex differences in compositional plaque volume progression in patients with stable coronary artery disease: observations from a serial CCTA registry

Background

It is unclear whether sex impacts the plaque volume (PV) progression in patients with stable coronary artery disease (CAD).

Purpose

To explore whether the total and compositional PV progression rate differ according to sex.

Methods

We performed a prospective multinational registry of consecutive patients who underwent serial CCTA at ≥2-year interval. Total and compositional PV at baseline and follow-up were quantitatively analysed and normalized using the analysed total vessel length. Multivariate linear regression models were constructed for each women and men.

Results

Of the 1,255 patients included (median CT interval 3.8 years), 543 were women and 712 were men. Women were older (62±9 years vs. 59±9 years, p<0.001) and had higher total cholesterol level (195±41mg/dL vs. 187±39mg/dL, p=0.002). Prevalence of hypertension, diabetes, and family history of CAD were not different (all p>0.05).

At baseline, men possessed greater total PV (131.5±230.5mm3 vs. 97.7±193.6mm3, p=0.005) and a higher prevalence of high-risk plaques (HRP) than women (31% vs. 20%, p<0.001). Annual total PV progression rate was greater in men, driven by the greater non-calcified PV progression (TABLE).

In multivariate analysis (TABLE), although total PV progression rate was not different, women were associated with greater calcified PV progression (β=2.83, p=0.004) but slower non-calcified PV progression (β=-3.39, p=0.008) and less development of HRP (β=-0.18, p=0.049) than men.

CCTA findings according to sex Univariate analysis Female Sex in Multivariable Analysis Women (n=543) Men (n=712) P β SE P Agatston CACS, /year 0.44±0.7 0.4±0.7 0.332 0.106 0.04 0.006 Total PVnormalized, mm3/year 14.7±23.4 17.8±26.2 0.026 -0.56 1.33 0.677 Calcified PVnormalized, mm3/year 10.5±21.5 10.0±19.1 0.670 2.83 0.98 0.004 Non-calcified PVnormalized, mm3/year 4.2±17.3 7.8±21.2 0.001 -3.39 1.28 0.008 Development of high-risk plaque*, n (%) 86 (15.8) 139 (19.5) 0.092 -0.18 0.09 0.049 In linear multivariate regression analysis adjusted with age, race, HTN, DM, family history, smoking, LDL, statin, anti-platelets, beta-blockers, and PV at baseline, women were associated with greater calcified PV progression and slower non-calcified PV progression. (High-risk plaque was defined as ≥2 of low-attenuation plaque, spotty calcification, and positive remodelling.)

Conclusion

In this large CCTA cohort, we found that the compositional PV progression differs according to sex. These findings, which are hypothesis generating, suggest that comprehensive plaque evaluation may contribute to further refine risk stratification according to sex.

Acknowledgement/Funding

This work was supported by the National Research Foundation of Korea funded by the Ministry of Science and ICT (Grant No. 2012027176).

P2722Optimizing diagnosis of obstrutive coronary artery disease by CT angiography and ischemia test: a randomized clinical trial

Aim

In patients with suspected coronary artery disease (CAD), computed tomographic angiography (CTA) may improve patient selection for invasive coronary angiography (ICA) as alternative to functional testing. However, the role of CTA in symptomatic patients after abnormal functional test is incompletely defined.

Methods and results

This randomized clinical trial conducted in single academic tertiary center selected 218 symptomatic patients (pts) with mild to moderately abnormal functional test referred to invasive coronary to receive either the originally intended ICA (n=103) or CTA (n=115). CTA interpretation and subsequent care decisions were made by the clinical team. Patients with high risk features on functional tests, previous acute coronary syndrome, previously documented CAD, chronic kidney disease (GFR <60 ml/min/1.73m2) or persistent atrial fibrillation were excluded. The primary endpoint was the percentage of ICA with no significant obstructive CAD (no stenosis ≥50%) in each group. Diagnostic and revascularization yields of ICA in either group were also assessed. Subjects averaged 68±9 years of age, 60% were male, 29% were diabetic. Nuclear perfusion stress test was used in 33.9% in CTA group and 31.1% in control group (p=0.655). Mean post (functional) test probability of obstructive CAD was 34%. Overall prevalence of obstructive CAD was 32.1%. In the CTA group, ICA angiography was cancelled by referring physicians in 83 of the pts (72.2%) after receiving CTA results. For those undergoing ICA, nonobstructive CAD was found in 5 pts (15.6%) in the CTA-guided arm and 60 (58.3%) in the usual care arm (P<0.001). Mean cumulative radiation exposure related to diagnostic work up was similar in both groups (6±14 vs 5±14mSv, P=0.152), but a greater cumulative contrast dose in the CTA-guided group (87.5±21 vs 77±40, p=0.026) was observed. Both diagnostic (84.4% vs 41.7, p<0.001) and revascularization (71.9% vs 38.8%, p=0.001) yields were significantly higher for CTA-guided ICA as compared to standard functional test-guided ICA.

Conclusions

In patients with suspected CAD and mild to moderately abnormal functional test, a diagnostic strategy including computed tomographic angiography as gatekeeper is effective and significantly improves diagnostic and revascularization yields of invasive coronary angiography.

Absence of microsatellite instability and BRAF (V600E) mutation in testicular germ cell tumors

Testicular germ cell tumors (TGCT) are the most common malignant neoplasm in young men. DNA mismatch repair deficiency can lead to microsatellite instability (MSI), an important mechanism of genetic instability. A mutation of the BRAF gene has been implicated in the pathogenesis of several solid tumors and has recently become an important therapeutic target. The role of MSI and BRAF gene mutation in TGCT, particularly in refractory disease, is poorly understood and reported findings are controversial. In this study, we aimed to determine the frequency and clinical impact of MSI status and BRAF mutations in TGCT. DNA was isolated from formalin-fixed paraffin embedded (FFPE) tissue from 150 TGCT cases. The MSI phenotype was evaluated using multiplex PCR for five quasimonomorphic mononucleotide repeat markers. Exon 15 of the BRAF oncogene (V600E) was analyzed by PCR, followed by direct sequencing. Sixteen percent of cases were considered to have refractory disease. In a small subset of cases (17 for MSI and 18 for BRAF), the quantity and quality of DNA recovery were poor and therefore, were unable to be analyzed. The remaining 133 TGCT cases showed a complete absence of MSI. Of the 132 cases successfully evaluated for BRAF mutations, all were V600E wild-type. In conclusion, despite a distinct response of testicular germ cell tumors to therapy, microsatellite instability, and the BRAF V600E mutation were absent in all testicular germ cell tumors tested in this study.

[Calcifying tendinitis of the rotator cuff with focal umeral osteolysis. Imaging features]

Calcifying tendinitis occurs most commonly in the rotator cuff tendons, particularly involving the supraspinatus tendon insertion, and is often asymptomatic. Cortical erosion secondary to calcifying tendinitis has been reported in multiple locations, including in the rotator cuff tendons. The authors report two cases of symptomatic calcifying tendinitis involving the infraspinatus tendon with cortical erosion with correlative radiographic, and MR findings. The importance of considering this diagnosis when evaluating lytic lesions of the humerus and the imaging differential diagnosis of calcifying tendinitis and cortical erosion are discussed.

[Calcifying tendinitis of the rotator cuff with focal umeral osteolysis. Imaging features.]

Calcifying tendinitis occurs most commonly in the rotator cuff tendons, particularly involving the supraspinatus tendon insertion, and is often asymptomatic. Cortical erosion secondary to calcifying tendinitis has been reported in multiple locations, including in the rotator cuff tendons. The authors report two cases of symptomatic calcifying tendinitis involving the infraspinatus tendon with cortical erosion with correlative radiographic, and MR findings. The importance of considering this diagnosis when evaluating lytic lesions of the humerus and the imaging differential diagnosis of calcifying tendinitis and cortical erosion are discussed.