Genetics and cardiovascular disease: a policy statement from the American Heart Association

Cardiovascular Disease in Childhood, Adolescent, and Young Adult Cancer Survivors: The Impact of Family History of Premature Heart Disease

Purpose: Childhood, adolescent, and young adult (CAYA) cancer survivors (age 0-39 years at diagnosis) are at increased risk of cardiovascular disease (CVD). Family history of early heart disease increases the risk of CVD in the general population; however, it is unknown whether this association is seen in CAYA cancer survivors. Methods: Self-report data from the National Health and Nutrition Examination Survey (2005-2018) were used to identify CAYA survivors (>5 years post-diagnosis). The risk of CVD based on family history status (parent or sibling with a diagnosis of heart attack or angina before age 50 years), personal sociodemographic factors, personal medical history factors, and personal behavioral risk factors was determined using logistic regression models. Results: Included were 95 CAYA survivors with CVD and 491 CAYA survivors without CVD. The odds of CVD were significantly higher in survivors with a first-degree family history of early heart disease (odds ratio [OR]: 2.06, 95% confidence interval [CI]: 1.14-3.74). A history of diabetes (OR: 2.61, 95% CI: 1.41-4.84), hypertension (OR: 1.81, 95% CI: 1.04-3.16), and any smoking (OR: 2.19, 95% CI: 1.19-4.02) was also associated with higher odds of CVD in CAYA survivors. Reporting any physical activity in the past month was associated with lower odds (OR: 0.54, 95% CI: 0.30-0.97) of CVD. Conclusions: Family history of early heart disease was associated with increased odds of CVD in CAYA cancer survivors. Obtaining complete and accurate family history information is important both at time of diagnosis and throughout follow-up.

Mendelian randomization and pathway analysis demonstrate shared genetic associations between lupus and coronary artery disease

Coronary artery disease (CAD) is a leading cause of death in patients with systemic lupus erythematosus (SLE). Despite clinical evidence supporting an association between SLE and CAD, pleiotropy-adjusted genetic association studies are limited and focus on only a few common risk loci. Here, we identify a net positive causal estimate of SLE-associated non-HLA SNPs on CAD by traditional Mendelian randomization (MR) approaches. Pathway analysis using SNP-to-gene mapping followed by unsupervised clustering based on protein-protein interactions (PPIs) identifies biological networks composed of positive and negative causal sets of genes. In addition, we confirm the casual effects of specific SNP-to-gene modules on CAD using only SNP mapping to each PPI-defined functional gene set as instrumental variables. This PPI-based MR approach elucidates various molecular pathways with causal implications between SLE and CAD and identifies biological pathways likely causative of both pathologies, revealing known and novel therapeutic interventions for managing CAD in SLE.

Polygenic Risk Scores for Cardiovascular Disease: A Scientific Statement From the American Heart Association

Cardiovascular disease is the leading contributor to years lost due to disability or premature death among adults. Current efforts focus on risk prediction and risk factor mitigation' which have been recognized for the past half-century. However, despite advances, risk prediction remains imprecise with persistently high rates of incident cardiovascular disease. Genetic characterization has been proposed as an approach to enable earlier and potentially tailored prevention. Rare mendelian pathogenic variants predisposing to cardiometabolic conditions have long been known to contribute to disease risk in some families. However, twin and familial aggregation studies imply that diverse cardiovascular conditions are heritable in the general population. Significant technological and methodological advances since the Human Genome Project are facilitating population-based comprehensive genetic profiling at decreasing costs. Genome-wide association studies from such endeavors continue to elucidate causal mechanisms for cardiovascular diseases. Systematic cataloging for cardiovascular risk alleles also enabled the development of polygenic risk scores. Genetic profiling is becoming widespread in large-scale research, including in health care-associated biobanks, randomized controlled trials, and direct-to-consumer profiling in tens of millions of people. Thus, individuals and their physicians are increasingly presented with polygenic risk scores for cardiovascular conditions in clinical encounters. In this scientific statement, we review the contemporary science, clinical considerations, and future challenges for polygenic risk scores for cardiovascular diseases. We selected 5 cardiometabolic diseases (coronary artery disease, hypercholesterolemia, type 2 diabetes, atrial fibrillation, and venous thromboembolic disease) and response to drug therapy and offer provisional guidance to health care professionals, researchers, policymakers, and patients.

Multimedia Security Situation Prediction Based on Optimization of Radial Basis Function Neural Network Algorithm

Aiming at the problem of prediction accuracy in network situation awareness, a network security situation prediction method based on a generalized radial basis function (RBF) neural network is proposed. This method uses the K-means clustering algorithm to determine the data center and expansion function of the RBF and uses the least-mean-square algorithm to adjust the weights to obtain the nonlinear mapping relationship between the situation value before and after the situation and carry out the situation prediction. Simulation experiments show that this method can obtain situation prediction results more accurately and improve the active security protection of network security. Compared with the PSO-RBF model, AFSA-RBF model, and IAFSA-RBF model, the maximum relative error and minimum relative error of the IAFSA-PSO-RBF model are reduced by 14.27%, 8.91%, and 32.98%, respectively, and the minimum relative error is reduced by 1.69%, 12.97%, and 0.61%, respectively. This shows that the IAFSA-PSO-RBF model has reduced the prediction error interval, and the average relative error is 5%. Compared with the other three models, the accuracy rate is improved by more than 5%, and it has met the requirements for the prediction of the network security situation.

Endogenous Retrovirus-Derived lncRNA BANCR Promotes Cardiomyocyte Migration in Humans and Non-human Primates

Transposable elements (TEs) comprise nearly half of the human genome and are often transcribed or exhibit cis-regulatory properties with unknown function in specific processes such as heart development. In the case of endogenous retroviruses (ERVs), a TE subclass, experimental interrogation is constrained as many are primate-specific or human-specific. Here, we use primate pluripotent stem-cell-derived cardiomyocytes that mimic fetal cardiomyocytes in vitro to discover hundreds of ERV transcripts from the primate-specific MER41 family, some of which are regulated by the cardiogenic transcription factor TBX5. The most significant of these are located within BANCR, a long non-coding RNA (lncRNA) exclusively expressed in primate fetal cardiomyocytes. Functional studies reveal that BANCR promotes cardiomyocyte migration in vitro and ventricular enlargement in vivo. We conclude that recently evolved TE loci such as BANCR may represent potent de novo developmental regulatory elements that can be interrogated with species-matching pluripotent stem cell models.

Establishment of Specialized Clinical Cardiovascular Genetics Programs: Recognizing the Need and Meeting Standards: A Scientific Statement From the American Heart Association

Cardiovascular genetics is a rapidly evolving subspecialty within cardiovascular medicine, and its growth is attributed to advances in genome sequencing and genetic testing and the expanding understanding of the genetic basis of multiple cardiac conditions, including arrhythmias (channelopathies), heart failure (cardiomyopathies), lipid disorders, cardiac complications of neuromuscular conditions, and vascular disease, including aortopathies. There have also been great advances in clinical diagnostic methods, as well as in therapies to ameliorate symptoms, slow progression of disease, and mitigate the risk of adverse outcomes. Emerging challenges include interpretation of genetic test results and the evaluation, counseling, and management of genetically at-risk family members who have inherited pathogenic variants but do not yet manifest disease. With these advances and challenges, there is a need for specialized programs combining both cardiovascular medicine and genetics expertise. The integration of clinical cardiovascular findings, including those obtained from physical examination, imaging, and functional assessment, with genetic information allows for improved diagnosis, prognostication, and cascade family testing to identify and to manage risk, and in some cases to provide genotype-specific therapy. This emerging subspecialty may ultimately require a new cardiovascular subspecialist, the genetic cardiologist, equipped with these combined skills, to permit interpretation of genetic variation within the context of phenotype and to extend the utility of genetic testing. This scientific statement outlines current best practices for delivering cardiovascular genetic evaluation and care in both the pediatric and the adult settings, with a focus on team member expertise and conditions that most benefit from genetic evaluation.

2019 HRS expert consensus statement on evaluation, risk stratification, and management of arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is an arrhythmogenic disorder of the myocardium not secondary to ischemic, hypertensive, or valvular heart disease. ACM incorporates a broad spectrum of genetic, systemic, infectious, and inflammatory disorders. This designation includes, but is not limited to, arrhythmogenic right/left ventricular cardiomyopathy, cardiac amyloidosis, sarcoidosis, Chagas disease, and left ventricular noncompaction. The ACM phenotype overlaps with other cardiomyopathies, particularly dilated cardiomyopathy with arrhythmia presentation that may be associated with ventricular dilatation and/or impaired systolic function. This expert consensus statement provides the clinician with guidance on evaluation and management of ACM and includes clinically relevant information on genetics and disease mechanisms. PICO questions were utilized to evaluate contemporary evidence and provide clinical guidance related to exercise in arrhythmogenic right ventricular cardiomyopathy. Recommendations were developed and approved by an expert writing group, after a systematic literature search with evidence tables, and discussion of their own clinical experience, to present the current knowledge in the field. Each recommendation is presented using the Class of Recommendation and Level of Evidence system formulated by the American College of Cardiology and the American Heart Association and is accompanied by references and explanatory text to provide essential context. The ongoing recognition of the genetic basis of ACM provides the opportunity to examine the diverse triggers and potential common pathway for the development of disease and arrhythmia.

The emerging role of sorting nexins in cardiovascular diseases

The sorting nexin (SNX) family consists of a diverse group of cytoplasmic- and membrane-associated phosphoinositide-binding proteins that play pivotal roles in the regulation of protein trafficking. This includes the entire endocytic pathway, such as endocytosis, endosomal sorting, and endosomal signaling. Dysfunctions of SNX pathway are involved in several forms of cardiovascular disease (CVD). Moreover, SNX gene variants are associated with CVDs. In this review, we discuss the current knowledge on SNX-mediated regulatory mechanisms and their roles in the pathogenesis and treatment of CVDs.

The impact of cardiovascular genetic counseling on patient empowerment

Cardiovascular genetic counseling (CVGC) is recommended for a variety of inherited heart conditions; however, its impact on patient empowerment has not been assessed. The Genetic Counseling Outcome Scale (GCOS) is a validated patient reported outcome tool which measures empowerment to capture the impact of clinical genetics services. As a routine clinical practice at our center, adult patients attending a CVGC appointment complete the 24-item GCOS survey and a 5-item survey on knowledge of cardiac surveillance recommendations for relatives prior to the clinic visit. To investigate the effect of CVGC, we contacted participants after the appointment to repeat these surveys prior to genetic test result disclosure. Forty-two participants completed pre- and post-GC surveys. The mean difference between pre- and post-GC empowerment scores was 17.5 points (mean pre-GC score = 118.5, mean post-GC score = 136, p < 0.0001; effect size, d = 0.94). Forty percent of individuals (17/42) were aware of surveillance recommendations for at-risk family members prior to GC; this increased to 76% of individuals (32/42) post-GC (p < 0.01). This is the first study to explore patient empowerment before and after GC in a cardiology setting. The results demonstrate a significant increase in empowerment and awareness of recommendations for at-risk relatives as a result of CVGC. This study demonstrates the utility of CVGC in patient care.

Should pretest genetic counselling be required for patients pursuing genomic sequencing? Results from a survey of participants in a large genomic implementation study

PURPOSE

We assessed the decision-making of individuals pursuing genomic sequencing without a requirement for pretest genetic counselling. We sought to describe the extent to which individuals who decline genetic counselling reported decisional conflict or struggled to make a decision to pursue genomic testing.

METHODS

We administered a 100-item survey to 3037 individuals who consented to the Return of Actionable Variants Empirical study, a genomic medicine implementation study supported by the National Institutes of Health (USA) eMERGE consortium. The primary outcomes of interest were self-reported decisional conflict about the decision to participate in the study and time required to reach a decision.

RESULTS

We received 2895 completed surveys (response rate=95.3%), and of these respondents 97.8% completed the decisional conflict scale in its entirety. A majority of individuals (63%) had minimal or no decisional conflict about the pursuit of genomic sequencing and were able to reach a decision quickly (78%). Multivariable logistic regression analyses identified several characteristics associated with decisional conflict, including lower education, lower health literacy, lower self-efficacy in coping, lack of prior experience with genetic testing, not discussing study participation with a family member or friend, and being male.

CONCLUSION

As genomic sequencing is used more widely, genetic counselling resources may not be sufficient to meet demand. Our results challenge the notion that all individuals need genetic counselling in order to make an informed decision about genomic sequencing.

CardioVAI: An automatic implementation of ACMG-AMP variant interpretation guidelines in the diagnosis of cardiovascular diseases

Variant interpretation for the diagnosis of genetic diseases is a complex process. The American College of Medical Genetics and Genomics, with the Association for Molecular Pathology, have proposed a set of evidence-based guidelines to support variant pathogenicity assessment and reporting in Mendelian diseases. Cardiovascular disorders are a field of application of these guidelines, but practical implementation is challenging due to the genetic disease heterogeneity and the complexity of information sources that need to be integrated. Decision support systems able to automate variant interpretation in the light of specific disease domains are demanded. We implemented CardioVAI (Cardio Variant Interpreter), an automated system for guidelines based variant classification in cardiovascular-related genes. Different omics-resources were integrated to assess pathogenicity of every genomic variant in 72 cardiovascular diseases related genes. We validated our method on benchmark datasets of high-confident assessed variants, reaching pathogenicity and benignity concordance up to 83 and 97.08%, respectively. We compared CardioVAI to similar methods and analyzed the main differences in terms of guidelines implementation. We finally made available CardioVAI as a web resource (http://cardiovai.engenome.com/) that allows users to further specialize guidelines recommendations.

Coronary blood flow volume change is negatively associated with platelet aggregability in patients with non-obstructive ischemic heart disease who have no anti-platelet agents

BACKGROUND

Thrombus formation is one of the main pathogeneses of acute coronary syndrome with atherosclerotic rupture. Previous studies have reported that atherosclerosis increases platelet aggregability and that vascular endothelial dysfunction reflects early change of atherosclerosis. However, the relationship between coronary endothelial dysfunction and platelet reactivity remains unclear. Therefore, in this study, we investigated the relationship between them in non-obstructive ischemic heart disease (IHD) patients.

METHODS

Three hundred sixty-eight consecutive stable patients with suspected angina presenting non-obstructive coronary arteries (<50% diameter) in coronary angiography were investigated with the intracoronary acetylcholine provocation test and measured adenosine triphosphate-induced coronary flow reserve. Finally, 25 non-obstructive IHD patients who had no anti-platelet agents were assessed for the relationship between coronary blood flow volume (CBFV) change and platelet aggregability as P2Y12 reaction unit (PRU) by VerifyNow P2Y12 assay system.

RESULTS

CBFV change by intracoronary 20 μg/kg per minute acetylcholine provocation showed a significant negative correlation with platelet aggregability as PRU (r = 0.44, P = 0.03). Conversely, there was no significant correlation between PRU and endothelial function as coronary flow reserve. Furthermore, multivariable linear regression analysis indicated that an incremental CBFV change was independently associated with PRU (β = 0.63, P < 0.001) in non-obstructive IHD patients.

CONCLUSIONS

In patients with non-obstructive IHD, CBFV change was significantly associated with platelet aggregability, indicating that coronary endothelial dysfunction might mediate higher platelet aggregability.

Spontaneous Coronary Artery Dissection: Current State of the Science: A Scientific Statement From the American Heart Association

Spontaneous coronary artery dissection (SCAD) has emerged as an important cause of acute coronary syndrome, myocardial infarction, and sudden death, particularly among young women and individuals with few conventional atherosclerotic risk factors. Patient-initiated research has spurred increased awareness of SCAD, and improved diagnostic capabilities and findings from large case series have led to changes in approaches to initial and long-term management and increasing evidence that SCAD not only is more common than previously believed but also must be evaluated and treated differently from atherosclerotic myocardial infarction. High rates of recurrent SCAD; its association with female sex, pregnancy, and physical and emotional stress triggers; and concurrent systemic arteriopathies, particularly fibromuscular dysplasia, highlight the differences in clinical characteristics of SCAD compared with atherosclerotic disease. Recent insights into the causes of, clinical course of, treatment options for, outcomes of, and associated conditions of SCAD and the many persistent knowledge gaps are presented.

Prevalence of Pathogenic Gene Mutations and Prognosis Do Not Differ in Isolated Left Ventricular Dysfunction Compared With Dilated Cardiomyopathy

Background:

Genetic evaluation is recommended in patients with unexplained dilated cardiomyopathy (DCM), but its diagnostic yield and prognostic relevance in unexplained isolated left ventricular dysfunction (LVdys) is unknown.

Methods and Results:

A total of 127 LVdys and 262 DCM patients underwent genetic screening. Long-term outcome consisted of a combined end point of life-threatening arrhythmia, heart transplantation, and death. At baseline, LVdys patients were younger and had less frequently New York Heart Association class ≥3 when compared with DCM (55±13 versus 58±12; P =0.019 and 21% versus 36%; P =0.003, respectively). The prevalence of familial disease and pathogenic mutations was similar in LVdys and DCM (45% versus 40%; P =0.37 and 19% versus 17%; P =0.61, respectively). After a follow-up of 56 (31–82) months, outcome did not differ in LVdys compared with DCM patients (hazard ratio, 0.83; 95% confidence interval, 0.47–1.45; P =0.51). Overall, outcome was less favorable in patients with a genetic mutation or familial disease when compared with those without (hazard ratio, 2.7; 95% confidence interval, 1.07–7.7; P =0.048 and hazard ratio, 2.2; 95% confidence interval, 1.2–4.2; P =0.013, respectively). Thus, the diagnostic yield of genetic testing in LVdys and DCM is similarly high. The presence of a gene mutation or familial predisposition results in an equally worse prognosis.

Conclusions:

Genetic evaluation is advised in LVdys patients and should not merely be restricted to DCM.

Cardiovascular disease: The rise of the genetic risk score

In a Perspective, Joshua Knowles and Euan Ashley discuss the potential for use of genetic risk scores in clinical practice.

Genetic Testing in Pediatric Cardiomyopathy

Genetic testing is recommended in patients with dilated cardiomyopathy (DCM); however, limited studies demonstrate high yields of genetic testing in non-hypertrophic (HCM) patients. Furthermore, there is sparse genotype-phenotype data in pediatric DCM patients. We performed a retrospective review of 70 consecutive probands with cardiomyopathy (non-HCM) who underwent genetic evaluation. Mean age at presentation was 5.48 years. Echocardiography revealed mean ejection fraction of 32.4%. The LVEDd z score ranged from - 5.7 to + 15.9. Cardiomyopathy was classified as dilated in 56, 10 with non-compaction, 2 with restrictive, and 2 with ARVC. TTN gene mutations were the most common gene involved. Genetic testing was negative in 16/70 (23%) giving a yield of 77% including VUS. 33% (23/70) of probands had a positive family history among whom the diagnostic yield was 57% (13/23) for pathogenic mutations. Yield for positive genetic testing in the DCM with positive family history group was 9/18 (50%). There were 6 deaths (9%) and 26/70 (37%) underwent transplantation. More frequent cardiac transplantations (48 vs. 34%) and deaths (17 vs. 2%) were seen in mutation-positive vs. mutation-negative subgroups. This study demonstrates an increasing yield of genetic testing in DCM although with a high rate of VUS detection. Use of genetic information for better management and prognostication will require big data analysis.

Genetic markers: Potential candidates for cardiovascular disease

The effective prevention of cardiovascular disease depends upon the ability to recognize the high-risk individuals at an early stage of the disease or long before the development of adverse events. Evolving technologies in the fields of proteomics, metabolomics, and genomics have played a significant role in the discovery of cardiovascular biomarkers, but so far these methods have achieved the modest success. Hence, there is a crucial need for more reliable, suitable, and lasting diagnostic and therapeutic markers to screen the disease well in time to start the clinical aid to the patients. Gene polymorphisms associated with the cardiovascular disease play a decisive role in the disease onset. Therefore, the genetic marker evaluation to classify high-risk patients from low-risk patients trends an effective approach to patient management and care. Currently, there are no genetic markers available for extensive adoption as risk factors for coronary vascular disease, yet, there are numerous promising, biologically acceptable candidates. Many of these gene biomarkers, alone or in combination, can play an essential role in the prediction of cardiovascular risk. The present review highlights some putative emerging genetic biomarkers that could facilitate more authentic and fast diagnosis of CVD. This review also briefly describes few technological approaches employed in the biomarker search.

Enhancing Literacy in Cardiovascular Genetics: A Scientific Statement From the American Heart Association

Advances in genomics are enhancing our understanding of the genetic basis of cardiovascular diseases, both congenital and acquired, and stroke. These advances include finding genes that cause or increase the risk for childhood and adult-onset diseases, finding genes that influence how patients respond to medications, and the development of genetics-guided therapies for diseases. However, the ability of cardiovascular and stroke clinicians to fully understand and apply this knowledge to the care of their patients has lagged. This statement addresses what the specialist caring for patients with cardiovascular diseases and stroke should know about genetics; how they can gain this knowledge; how they can keep up-to-date with advances in genetics, genomics, and pharmacogenetics; and how they can apply this knowledge to improve the care of patients and families with cardiovascular diseases and stroke.

Patient Stratification Using Electronic Health Records from a Chronic Disease Management Program

OBJECTIVE

The goal of this study is to devise a machine learning framework to assist care coordination programs in prognostic stratification to design and deliver personalized care plans and to allocate financial and medical resources effectively.

MATERIALS AND METHODS

This study is based on a de-identified cohort of 2,521 hypertension patients from a chronic care coordination program at the Vanderbilt University Medical Center. Patients were modeled as vectors of features derived from electronic health records (EHRs) over a six-year period. We applied a stepwise regression to identify risk factors associated with a decrease in mean arterial pressure of at least 2 mmHg after program enrollment. The resulting features were subsequently validated via a logistic regression classifier. Finally, risk factors were applied to group the patients through model-based clustering.

RESULTS

We identified a set of predictive features that consisted of a mix of demographic, medication, and diagnostic concepts. Logistic regression over these features yielded an area under the ROC curve (AUC) of 0.71 (95% CI: [0.67, 0.76]). Based on these features, four clinically meaningful groups are identified through clustering - two of which represented patients with more severe disease profiles, while the remaining represented patients with mild disease profiles.

DISCUSSION

Patients with hypertension can exhibit significant variation in their blood pressure control status and responsiveness to therapy. Yet this work shows that a clustering analysis can generate more homogeneous patient groups, which may aid clinicians in designing and implementing customized care programs.

CONCLUSION

The study shows that predictive modeling and clustering using EHR data can be beneficial for providing a systematic, generalized approach for care providers to tailor their management approach based upon patient-level factors.

Understanding Genetics and Pediatric Cardiac Health

Congenital heart defects (CHD) continue to be the most prevalent birth defect that occurs worldwide in approximately 6-8 of every 1,000 live births. High rates of morbidity and mortality in infants, children, and adults living with CHD place a growing need for health care professionals (HCPs) to better understand potentially modifiable genetic and environmental influences. This paper will present examples of research and governmental initiatives that support genetics education and research and a review of known genetic factors associated with CHD development.

ORGANIZING CONSTRUCT

A review of the known genetic factors on risk for CHD formation in infants will be provided to help health care professionals gain a greater understanding of the genetic influences on pediatric cardiac health.

CONCLUSIONS

There are known genetic pathways and risk factors that contribute to development of CHD. This paper is a primer for nurses and HCPs providing information of the genetics and inheritance patterns of CHD to be useful in daily clinical practice.

CLINICAL RELEVANCE

Nurses work in multiple communities where they are uniquely positioned to educate and provide information about research and current models of care with families affected by CHD. Nurses and HCPs who better understand genetic risk factors associated with CHD development can more promptly refer and offer treatment for these children and families thus providing individuals of childbearing age with the necessary resources and information about risk factors.

Perceived economic burden associated with an inherited cardiac condition: a qualitative inquiry with families affected by arrhythmogenic right ventricular cardiomyopathy

PURPOSE

Significant gaps remain in the literature on the economic burden of genetic illness. We explored perceived economic burden associated with one inherited cardiac condition, arrhythmogenic right ventricular cardiomyopathy (ARVC).

METHODS

Semistructured interviews were held with individuals from families affected by ARVC. Data on the perceived financial and economic impacts of ARVC were used to identify emerging categories and themes using the method of constant comparison.

RESULTS

Data analysis revealed four themes that described participants' perceptions of the economic impact ARVC had on them and their families: (i) economic impact during childhood, (ii) impact on current and future employment, (iii) impact on current and future financial well-being, and (iv) no perceived economic impact.

CONCLUSIONS

This study is the first to explore the economic burden of ARVC from the perspective of affected families. It revealed a number of perceived burdens, from employment and career choices to worry about insurance for self and children, decreased household spending, and the need for childhood employment. Findings highlight potential areas of discussion for genetic counseling sessions, as well as areas for future research.Genet Med 18 6, 584-592.

Genetics and genotype-phenotype correlations in Finnish patients with dilated cardiomyopathy

Genetic analysis among patients with dilated cardiomyopathy (DCM) is becoming an important part of clinical assessment, as it is in hypertrophic cardiomyopathy (HCM). The genetics of DCM is complex and therefore next-generation sequencing strategies are essential when providing genetic diagnostics. To achieve maximum yield, the diagnostic approach should include comprehensive clinical phenotyping combined with high-quality, high-coverage deep sequencing of DCM-associated genes and clinical variant classification as a basis for defining true yield in genetic testing. Our study has combined a novel sequencing strategy and clinical interpretation to analyse the yield and genotype–phenotype correlations among well-phenotyped Finnish DCM patients.

Aims

Despite our increased understanding of the genetic basis of dilated cardiomyopathy (DCM), the clinical utility and yield of clinically meaningful findings of comprehensive next-generation sequencing (NGS)-based genetic diagnostics in DCM has been poorly described. We utilized a high-quality oligonucleotide-selective sequencing (OS-Seq)-based targeted sequencing panel to investigate the genetic landscape of DCM in Finnish population and to evaluate the utility of OS-Seq technology as a novel comprehensive diagnostic tool.

Methods and results

Using OS-Seq, we targeted and sequenced the coding regions and splice junctions of 101 genes associated with cardiomyopathies in 145 unrelated Finnish patients with DCM. We developed effective bioinformatic variant filtering strategy and implemented strict variant classification scheme to reveal diagnostic yield and genotype–phenotype correlations. Implemented OS-Seq technology provided high coverage of the target region (median coverage 410× and 99.42% of the nucleotides were sequenced at least 15× read depth). Diagnostic yield was 35.2% (familial 47.6% and sporadic 25.6%, P = 0.004) when both pathogenic and likely pathogenic variants are considered as disease causing. Of these, 20 (53%) were titin (TTN) truncations (non-sense and frameshift) affecting all TTN transcripts. TTN truncations accounted for 20.6% and 14.6% of the familial and sporadic DCM cases, respectively.

Conclusion

Panel-based, high-quality NGS enables high diagnostic yield especially in the familial form of DCM, and bioinformatic variant filtering is a reliable step in the process of interpretation of genomic data in a clinical setting.

Warfarin pharmacogenomics: current best evidence

The utility of using genetic information to guide warfarin dosing has remained unclear based on prior observational studies and small clinical trials. Two larger trials of warfarin and one of the acenocoumarol and phenprocoumon have recently been published. The COAG trial addressed the incremental benefit of adding genetic information to clinical information and demonstrated no benefit from the pharmacogenetic-based dosing strategy on the primary outcome. The EU-PACT UK trial compared an algorithm approach using genetic and clinical information to one that used a relatively fixed starting dose. The pharmacogenetic-based algorithms improved the primary outcome. The study of acenocoumarol and phenprocoumon compared a pharmacogenetic with a clinical algorithm and demonstrated no benefit on the primary outcome. The evidence to date does not support an incremental benefit of adding genetic information to clinical information on anticoagulation control. However, compared with fixed dosing, a pharmacogenetic algorithm can improve anticoagulation control.

Next-generation sequencing for the diagnosis of cardiac arrhythmia syndromes

Inherited arrhythmia syndromes are collectively associated with substantial morbidity, yet our understanding of the genetic architecture of these conditions remains limited. Recent technological advances in DNA sequencing have led to the commercialization of genetic testing now widely available in clinical practice. In particular, next-generation sequencing allows the large-scale and rapid assessment of entire genomes. Although next-generation sequencing represents a major technological advance, it has introduced numerous challenges with respect to the interpretation of genetic variation and has opened a veritable floodgate of biological data of unknown clinical significance to practitioners. In this review, we discuss current genetic testing indications for inherited arrhythmia syndromes, broadly outline characteristics of next-generation sequencing techniques, and highlight challenges associated with such testing. We further summarize future directions that will be necessary to address to enable the widespread adoption of next-generation sequencing in the routine management of patients with inherited arrhythmia syndromes.

Rationale for the Cytogenomics of Cardiovascular Malformations Consortium: A Phenotype Intensive Registry Based Approach

Cardiovascular malformations (CVMs) are the most common birth defect, occurring in 1%–5% of all live births. Although the genetic contribution to CVMs is well recognized, the genetic causes of human CVMs are identified infrequently. In addition, a failure of systematic deep phenotyping of CVMs, resulting from the complexity and heterogeneity of malformations, has obscured genotype-phenotype correlations and contributed to a lack of understanding of disease mechanisms. To address these knowledge gaps, we have developed the Cytogenomics of Cardiovascular Malformations (CCVM) Consortium, a multi-site alliance of geneticists and cardiologists, contributing to a database registry of submicroscopic genetic copy number variants (CNVs) based on clinical chromosome microarray testing in individuals with CVMs using detailed classification schemes. Cardiac classification is performed using a modification to the National Birth Defects Prevention Study approach, and non-cardiac diagnoses are captured through ICD-9 and ICD-10 codes. By combining a comprehensive approach to clinically relevant genetic analyses with precise phenotyping, the Consortium goal is to identify novel genomic regions that cause or increase susceptibility to CVMs and to correlate the findings with clinical phenotype. This registry will provide critical insights into genetic architecture, facilitate genotype-phenotype correlations, and provide a valuable resource for the medical community.

Does selection bias explain the obesity paradox among individuals with cardiovascular disease?

OBJECTIVES

The objectives of this article are to demonstrate that the obesity paradox may be explained by collider stratification bias and to estimate the biasing effects of unmeasured common causes of cardiovascular disease (CVD) and mortality on the observed obesity-mortality relationship.

METHODS

We use directed acyclic graphs, regression modeling, and sensitivity analyses to explore whether the observed protective effect of obesity among individuals with CVD can be plausibly attributed to selection bias. Data from the third National Health and Examination Survey was used for the analyses.

RESULTS

The adjusted total effect of obesity on mortality was a risk difference (RD) of 0.03 (95% confidence interval [CI]: 0.02, 0.05). However, the controlled direct effect of obesity on mortality among individuals without CVD was RD = 0.03 (95% CI: 0.01, 0.05) and RD = -0.12 (95% CI: -0.20, -0.04) among individuals with CVD. The adjusted total effect estimate demonstrates an increased number of deaths among obese individuals relative to nonobese counterparts, whereas the controlled direct effect shows a paradoxical decrease in morality among obese individuals with CVD.

CONCLUSIONS

Sensitivity analysis demonstrates unmeasured confounding of the mediator-outcome relationship provides a sufficient explanation for the observed protective effect of obesity on mortality among individuals with CVD.

Development of a communication protocol for telephone disclosure of genetic test results for cancer predisposition

Background

Dissemination of genetic testing for disease susceptibility, one application of “personalized medicine”, holds the potential to empower patients and providers through informed risk reduction and prevention recommendations. Genetic testing has become a standard practice in cancer prevention for high-risk populations. Heightened consumer awareness of “cancer genes” and genes for other diseases (eg, cardiovascular and Alzheimer’s disease), as well as the burgeoning availability of increasingly complex genomic tests (ie, multi-gene, whole-exome and -genome sequencing), has escalated interest in and demand for genetic risk assessment and the specialists who provide it. Increasing demand is expected to surpass access to genetic specialists. Thus, there is urgent need to develop effective and efficient models of delivery of genetic information that comparably balance the risks and benefits to the current standard of in-person communication.

Objective

The aim of this pilot study was to develop and evaluate a theoretically grounded and rigorously developed protocol for telephone communication of BRCA1/2 (breast cancer) test results that might be generalizable to genetic testing for other hereditary cancer and noncancer syndromes.

Methods

Stakeholder data, health communication literature, and our theoretical model grounded in Self-Regulation Theory of Health Behavior were used to develop a telephone communication protocol for the communication of BRCA1/2 genetic test results. Framework analysis of selected audiotapes of disclosure sessions and stakeholders’ feedback were utilized to evaluate the efficacy and inform refinements to this protocol.

Results

Stakeholder feedback (n=86) and audiotapes (38%, 33/86) of telephone disclosures revealed perceived disadvantages and challenges including environmental factors (eg, non-private environment), patient-related factors (eg, low health literacy), testing-related factors (eg, additional testing needed), and communication factors (eg, no visual cues). Resulting modifications to the communication protocol for BRCA1/2 test results included clarified patient instructions, scheduled appointments, refined visual aids, expanded disclosure checklist items, and enhanced provider training.

Conclusions

Analyses of stakeholders’ experiences and audiotapes of telephone disclosure of BRCA1/2 test results informed revisions to communication strategies and a protocol to enhance patient outcomes when utilizing telephone to disclose genetic test results.

Arrhythmogenic right ventricular cardiomyopathy (ARVC): cardiovascular magnetic resonance update

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is one of the most arrhythmogenic forms of inherited cardiomyopathy and a frequent cause of sudden death in the young. Affected individuals typically present between the second and fourth decade of life with arrhythmias coming from the right ventricle. Pathogenic mutations in genes encoding the cardiac desmosome can be found in approximately 60% of index patients, leading to our current perception of ARVC as a desmosomal disease. Although ARVC is known to preferentially affect the right ventricle, early and/or predominant left ventricular involvement is increasingly recognized. Diagnosis is made by combining multiple sources of diagnostic information as prescribed by the "Task Force" criteria. Recent research suggests that electrical abnormalities precede structural changes in ARVC. Cardiovascular Magnetic Resonance (CMR) is an ideal technique in ARVC workup, as it provides comprehensive information on cardiac morphology, function, and tissue characterization in a single investigation. Prevention of sudden cardiac death using implantable cardioverter-defibrillators is the most important management consideration. This purpose of this paper is to provide an updated review of our understanding of the genetics, diagnosis, current state-of-the-art CMR acquisition and analysis, and management of patients with ARVC.

Provision of cardiovascular genetic counseling services: current practice and future directions

Cardiovascular genetic counseling has emerged as a specialty critical to the care of patients with heritable cardiovascular disease. Current strategies to meet the growing demand are not clear. We sought to characterize practice patterns of cardiac genetic counseling by developing a novel survey distributed to the National Society of Genetic Counselors (NSGC) Listserv to assess clinical practice, cardiovascular training, and education. Descriptive statistics were used to summarize clinical practice; Fisher's exact test and the Cochran-Armitage trend test were used to compare the practice of cardiovascular genetic counselors (CVGCs) to those who did not identify cardiology as a specialty (non-CVGCs). A total of 153 individuals completed the survey. Of the 105 participants who reported seeing a cardiac genetics patient, 42 (40%) identified themselves as a CVGC. The most common conditions for which genetic counseling was provided were hypertrophic cardiomyopathy (HCM) (71% of participants), dilated cardiomyopathy (DCM) (61%), long QT syndrome (LQTS) (56%), and genetic syndromes with cardiovascular disease (55%). CVGCs were significantly more confident than non-CVGCs in providing genetic counseling for seven cardiovascular diseases (2.3 × 10(-6) ≤ p ≤ 0.021). Eighty-six percent of genetic counselors sought additional education related to cardiovascular genetics and listed online courses as the most desirable method of learning. These data suggest a growing interest in cardiovascular genetic counseling and need for additional training resources among the NSGC membership.

Pharmacogenetics of heart failure

PURPOSE OF REVIEW

Novel medical approaches and personalized medicine seek to use genetic information to 'individualize' and improve diagnosis, prevention, and therapy. The personalized management of cardiovascular disease involves a large spectrum of potential applications, from diagnostics of monogenic disorders, to prevention and management strategies based on modifier genes, to pharmacogenetics, in which individual genetic information is used to optimize the pharmacological treatments.

RECENT FINDINGS

Evidence suggests that the common polymorphic variants of modifier genes could influence drug response in cardiovascular disease in a variety of areas, including heart failure, arrhythmias, dyslipidemia, and hypertension. In heart failure, common genetic variants of β-adrenergic receptors, α-adrenergic receptors, and endothelin receptors (among others) have been associated with variable response to heart failure therapies. The challenge remains to develop strategies to leverage this information in ways that personalize and optimize cardiovascular therapy based on a patient's genetic profile.

SUMMARY

Although advances in technologies will continue to transition personalized medicine from the research to the clinical setting, healthcare providers will need to reshape the clinical diagnostic paradigms. Ultimately, pharmacogenetics will give providers the options for improving patient management on the basis of pharmacogenetic data.

A pediatric approach to family history of cardiovascular disease: diagnosis, risk assessment, and management

The medical family history is a comprehensive and dynamic record of illnesses and other pertinent health information among family members. Family history is used to facilitate diagnosis, to identify family members at risk for developing a particular disease, and increasingly to manage disease. This article reviews the application of family history to pediatric cardiovascular disease. As more is learned about the genetic basis of cardiovascular disease, the family history will play an increasingly central role in management. Improved understanding of the causes of pediatric cardiovascular disease promises the opportunity to develop new diagnostic and therapeutic strategies.

A pharmacogenetic versus a clinical algorithm for warfarin dosing

BACKGROUND

The clinical utility of genotype-guided (pharmacogenetically based) dosing of warfarin has been tested only in small clinical trials or observational studies, with equivocal results.

METHODS

We randomly assigned 1015 patients to receive doses of warfarin during the first 5 days of therapy that were determined according to a dosing algorithm that included both clinical variables and genotype data or to one that included clinical variables only. All patients and clinicians were unaware of the dose of warfarin during the first 4 weeks of therapy. The primary outcome was the percentage of time that the international normalized ratio (INR) was in the therapeutic range from day 4 or 5 through day 28 of therapy.

RESULTS

At 4 weeks, the mean percentage of time in the therapeutic range was 45.2% in the genotype-guided group and 45.4% in the clinically guided group (adjusted mean difference, [genotype-guided group minus clinically guided group], -0.2; 95% confidence interval, -3.4 to 3.1; P=0.91). There also was no significant between-group difference among patients with a predicted dose difference between the two algorithms of 1 mg per day or more. There was, however, a significant interaction between dosing strategy and race (P=0.003). Among black patients, the mean percentage of time in the therapeutic range was less in the genotype-guided group than in the clinically guided group. The rates of the combined outcome of any INR of 4 or more, major bleeding, or thromboembolism did not differ significantly according to dosing strategy.

CONCLUSIONS

Genotype-guided dosing of warfarin did not improve anticoagulation control during the first 4 weeks of therapy. (Funded by the National Heart, Lung, and Blood Institute and others; COAG ClinicalTrials.gov number, NCT00839657.).