Predicting the presence of left atrial appendage thrombus with clinical features and transthoracic measurements using machine learning

Background

Atrial fibrillation and flutter (AF/AFl) increase the risk of thromboembolic events by promoting clot formation in the left atrium (LA), which can be visualised using transoesophageal echocardiography (TEE). Current guidelines recommend initiation of oral anticoagulation (OAC) in patients with AF/AFl based solely on CHA2DS2VASc score (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, history of stroke or thromboembolism, vascular disease, age 65 to 74 years, female sex). Yet, some patients develop left LA thrombus (LAT) and experience thromboembolic events despite OAC.

Purpose

We sought to develop and externally validate a machine learning model for prediction of presence of LAT based on clinical, laboratory and transthoracic echocardiography (TTE) features.

Methods

We analyzed data from the multicenter, prospective LATTEE registry (Left Atrial Thrombus on Transesophageal Echocardiography) that included patients from 13 sites who underwent TEE before cardioversion or ablation between November 2018 and March 2021. We used XgBoost model to predict presence of LAT in TEE based on 29 clinical features, 10 biomarkers and 5 TTE measurements. We trained and tested the model internally using 10-fold hold-out cross validation and data from 12 sites (N=2489). We then tested the final model externally using data from the 13th site (that had recruited most patients, N=400). We compared the predictive performance with that of CHA2DS2VASc score using areas under receiver operating curve (AUC) and DeLong test.

Results

In the training and internal testing cohort the median age was 67 (Inter Quartile Range [IQR] 59, 74), 63% were male, 85% received OAC and LAT was found in 8.4%. Ablation was the indication for TEE in 43%, cardioversion in 57%. In internal, 10-fold hold-out cross validation, the model achieved AUC of 0.755 (95% confidence interval [CI]: 0.722, 0.788) while CHA2DS2VASc performed significantly worse with AUC of 0.638 (95% CI: 0.604, 0.673), P<0.0001 (Figure 1). Left ventricular ejection fraction, rhythm at the time of study (AF/AFl or sinus rhythm) and age received the highest feature importance ranking (Figure 2).

In the external testing cohort the median age was 67 (IQR 59, 74), 66% were male, 88% received OAC, ablation was the indication for TEE in 49% of cases and LAT was found in 6.8%. In this external cohort, our model achieved AUC of 0.815 (95% CI: 0.741, 0.889) while CHA2DS2VASc performed significantly worse with AUC of 0.684 (95% CI: 0.583, 0.785), P=0.028.

Conclusion

Machine learning based on readily available clinical data allows accurate prediction of the presence of LAT in patients with AF/AFl irrespective of OAC treatment. Such score could be used to identify patients who should undergo TEE before ablation or cardioversion. Subsequent studies to clinically evaluate such application of our model as well as how the model can predict future thromboembolic events are warranted.

Funding Acknowledgement

Type of funding sources: None.

Atrial functional mitral regurgitation in patients qualified for pulmonary vein isolation: a negative prognostic factor for catheter ablation efficacy

Background

Atrial functional mitral regurgitation (AF-MR) related to atrial fibrillation (AF) could affect the effectiveness of the sinus rhythm restoring procedures.

Purpose

The aim of the study was to evaluate the impact of AF-MR on pulmonary vein isolation (PVI) efficacy.

Methods

One hundred thirty-six patients (65.4% males; mean age 56±11 years) with symptomatic paroxysmal or persistent AF qualified for PVI were enrolled into the study. AF-MR assessment was performed in transthoracic (TTE) and transesophageal (TEE) echocardiography before PVI procedure. PVI efficacy was evaluated in 3-month and long-term follow-up.

Results

AF-MR was diagnosed in 74.3% patient in transthoracic echocardiography (TTE) (trace: 26.5%, mild: 43.4%, moderate: 3.7%, severe 0.7%) and 94.9% in transesophageal echocardiography (TEE) (trace: 17.6%, mild: 59.6%, moderate: 16.2%, severe: 1.5%). PVI 3-month efficacy was 75.7% in 3-month and 64% in the long-term observation.

Severe AF-MR in TEE at baseline was associated with lower 3-month PVI efficacy (P=0.012) while moderate to severe AF MR in TEE was related to inefficient PVI assessed in long-term follow-up (P=0.041). In Kaplan- Meier analysis only moderate to severe AF-MR diagnosed in TEE had an impact on long-term procedure outcome (P=0.048).

Conclusions

Significant AF-MR confirmed by TEE predicts 3-month as well as long-term PVI efficacy.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The institutional budget of the First Department of Cardiology, Medical University of Silesia, Katowice, Poland

Teaching medical students how to deliver diagnoses of Down syndrome: Utility of an educational tool

OBJECTIVE

This study assessed whether using an educational tool increased the knowledge and perceived comfort level of first-year medical students in giving a diagnosis of Down syndrome.

METHOD

A total of 295 students taking a genetics course completed a knowledge questionnaire and Situations Inventory (aimed at assessing comfort with sharing certain information), prior to and following use of Brighter Tomorrows, a web-based educational module on giving parents a diagnosis of Down syndrome.

RESULTS

The pre-intervention mean on the knowledge survey was 3.67, which significantly increased to 5.47 following the intervention. Mean Situational Inventory scores were significantly higher pre-intervention (M = 45.5), which indicates greater discomfort, compared to post-intervention (M = 36.7). Qualitative analysis of responses regarding lessons learned fell into 5 major themes. The most common theme (48% of responses) was related to communication skills. The most frequently cited lesson learned was the importance of demonstrating empathy.

CONCLUSIONS

This study found that knowledge and perceived comfort levels of first-year medical students in giving a postnatal diagnosis of Down syndrome were significantly increased following use of an educational tool.

PRACTICE IMPLICATIONS

Educational modules can provide medical students with foundational knowledge on providing distressing information to help prepare for future clinical encounters.

P1816 Cerebral microembolism in low-risk patients with paroxysmal atrial fibrillation before and after pulmonary vein isolationCerebral microembolism in low-risk patients with paroxysmal atrial fibrillation

BACKGROUND

Invasive treatment of atrial fibrillation (AF) becomes more suitable and effective therapy. There are no consistent data describing the occurrence of potential neurological complications in low-risk patients with paroxysmal AF.

AIM

to determine the occurrence, consequences and risk factors for brain white matter hiperintensities (WMH) assessed in magnetic resonance imaging (MRI) in low-risk patients before and after pulmonary vein isolation (PVI) treatment.

METHODS

Eighty patients with symptomatic paroxysmal AF (median age: 58 years (IQR 50-63), K/M: 30/50), CHA2DS2-Vasc ≤ 3 (CHA2DS2-Vasc: 2 (IQR 1-2.5)) were included in the study. Before and after a minimum of 6-month period after PVI-RF treatment (med. 9,9 months, IQR 7.6-11.8 months) a clinical evaluation with brain MRI and Mini Mental State Examination (MMSE) test were determined. Severity of brain WMH in MRI was assessed in the Fazekas scale (pic 1). The efficacy of PVI-RF treatment analyzed in a 7-day Holter monitoring was confirmed in 43 (53.8%) patients.

RESULTS

Baseline WMH lesions were found in 55 (68.8%) patients. Patients with baseline WMH lesion obtained similar results in the MMSE test, compared to patients with a normal brain image in the MRI study. There was a statistically significant more frequent occurrence of cerebral WMH lesions among older patients, with a higher CHA2DS2-Vasc score, with left atrial (LA) dilatation and dysfunction. Factors affecting the severity of the WMH were: the co-occurrence of the patent foramen ovale (PFO) and coronary artery disease (CAD).

After PVI-RF treatment there were no significant changes in the presence and severity of WMH lesions. Similarly, there were no significant changes in the cognitive abilities assessed with MMSE test compared to the pre-procedural evaluation. There were also similar factors predisposing to brain WMH changes: older age, higher CHA2DS2-Vasc score and higher BMI. In turn, the degree of the brain WMH severity after observation period was dependent on age, higher CHA2DS2-Vasc score, presence of PFO and CAD and the initial LA function.

CONCLUSIONS Cerebral microembolism assessed in MRI is often found in low-risk patients with paroxysmal AF, and its presence and severity are associated with LA dilatation and dysfunction, age and higher CHA2DS2-Vasc score. Additional factors affecting the severity of WMH lesions are: the co-occurrence of PFO and CAD. PVI-RF procedure and its efficacy does not influence on MRI lesions. In the population of relatively young AF patients with no significant cardiovascular disease burden, cerebral microembolism is not related to cognitive impairment.

Abstract P1816 Figure. pic 1

Opportunities to improve recruitment into medical genetics residency programs: survey results of program directors and medical genetics residents

PURPOSE

Approximately 50% of medical genetics residency positions remain unfilled each year. This study was designed to assess current recruitment strategies used by program directors, to identify factors that influenced trainees to choose medical genetics as a career, and to use these results as a foundation to develop a strategic plan to address the challenges of recruitment.

METHODS

Two surveys were created, one for program directors and one for current medical genetics residents, to evaluate current recruiting efforts and institutional support for programs and to identify factors that helped trainees choose genetics as a career.

RESULTS

Program directors identified the most successful recruiting methods as "direct contact with residents or medical students" and "word of mouth" (80%). Residents listed having a mentor (50%), previous research in genetics (35%), and genetics coursework (33%) as the top reasons that influenced them to enter the field.

CONCLUSION

Geneticists should become more proactive in providing resources to students to help them understand a career as a medical geneticist and mentor those students/residents who show true interest in the field. Results of these surveys spurred the development of the Task Force on Medical Genetics Education and Training of the American College of Medical Genetics and Genomics.

Knowledge, attitudes, and beliefs of Arab-American women regarding inherited cancer risk

The increasing incidence of breast cancer in the Arab world, coupled with a relatively early age of onset, raises concern for the presence of hereditary risk factors in this population. However, due to potential structural and cultural barriers, Arab Americans make up the smallest percentage of individuals tested for Hereditary Breast and Ovarian Cancer Syndrome in the United States. The objectives of this qualitative pilot focus group of 13 Arab-American women were to explore attitudes, knowledge and beliefs regarding hereditary breast cancer in the Arab-American community in metropolitan Detroit, identify barriers that would prevent women from seeking hereditary cancer screening/testing and determine who women would talk to about inherited cancer. Results indicated that cultural beliefs and personal experiences with cancer influenced the women's perspectives on hereditary cancer risk. A high level of secrecy about cancer within Arab-American families was present, which may prevent accurate risk assessment and referral for genetic services. Other identified barriers that may influence hereditary risk assessment included stigma, fears and misconceptions of cancer. While these barriers were present, participants also expressed a strong need for education and tailored cancer risk information for their community.

African American-preponderant single nucleotide polymorphisms (SNPs) and risk of breast cancer

BACKGROUND

African American women more often present with more aggressive types of breast cancer than Caucasian women, but little is known whether genetic polymorphisms specific to or disproportionate in African Americans are associated with their risk of breast cancer.

METHODS

A population-based case-control study was conducted including 194 cases identified through the Metropolitan Detroit Cancer Surveillance System and 189 controls recruited through random digit dialing to examine polymorphisms in genes involved in estrogen metabolism and action.

RESULTS

The African American-specific CYP1A1 5639C allele was associated with an increased risk of breast cancer (odds ratio (OR)=2.34, 95% confidence interval (CI) 1.23-4.44) and this association with the CYP1A1 5639 locus was dependent on another polymorphism in the CYP3A4 gene (P=0.043 for the interaction). In addition, African American-predominant CYP1B1 432 Val allele was significantly more often found in the cases than in the controls overall and the HSD17B1 312 Gly allele was specifically associated with premenopausal breast cancer risk (OR=3.00, 95%CI 1.29-6.99).

CONCLUSION

These observations need to be confirmed in larger studies due to the limited statistical power of the study based on a small number of cases.

Predictors of decision making in families at risk for inherited breast/ovarian cancer

OBJECTIVE

The purpose of this study was to identify factors associated with decision making about inherited cancer risk information within families and determine the interdependence between survivors' and relatives' decision making.

DESIGN

A descriptive, cross-sectional design using a population-based sample of 146 dyads (N = 292) was used. Analyses included multilevel modeling using the Actor-Partner-Interdependence Model.

MAIN OUTCOME MEASURES

Decision making regarding inherited cancer risk information.

RESULTS

Several individual and family factors contributed toward survivors' and female relatives' decision making about inherited cancer risk information. Individual factors included the individual's perceptions of their family communication and cancer history. Family factors included survivors' and family members' age, communication and coping style that influenced the decision making of the other member of the dyad. Cancer worries and a monitoring coping style affected both seeking and avoiding decision making for survivors and relatives.

CONCLUSIONS

In view of the importance of genetic information upon family health outcomes, it is critical to address both individual and family factors that may influence decision making about cancer risk information and surveillance options for all members within the family.

Risk perception and cancer worries in families at increased risk of familial breast/ovarian cancer

While families at increased risk for familial breast/ovarian cancer continue to overestimate their cancer risk with increased cancer worries about the future, few studies have examined factors that affect inherited cancer risk perception and cancer worries in both survivors and unaffected female relatives. The purpose of this study was to examine variables that may affect cancer worries and risk perceptions from a family-based perspective in a racially diverse, community-based, random sample of 146 dyads consisting of adult female breast and/or ovarian cancer survivors and their unaffected female relatives (N=292). Results indicated that coping style, self-efficacy, partner's income, family role relationship, and cancer risk perception were significant contributors to the survivors' and their unaffected relatives' cancer worries. Significant variables for perception of cancer risk for both survivors and relatives included income, race, family history of cancer, and cancer worries. Relatives had a higher perception of cancer risk, whereas survivors had more cancer worries. Additionally, the level of cancer worries reported by one member of the dyad was related to the amount of worries reported by the other. The results from this study underscore the importance of clinicians addressing concerns of both affected and unaffected members of families at increased risk of cancer to assist them in managing cancer worries and having realistic risk appraisals to make informed decisions about their own and their family's health surveillance options.

The mechanism of action of DNA photolyases

Structural analysis, biochemistry and model studies have provided new insights into the mechanism of action of photolyases. The light-driven electron and energy transfer events that lead to the photolyase-catalyzed repair of lethal, mutagenic and carcinogenic UV-light-induced DNA lesions have all been examined in the past few years.