Genetics of early-onset coronary artery disease: from discovery to clinical translation

What Causes Premature Coronary Artery Disease?

PURPOSE OF REVIEW

This review provides an overview of genetic and non-genetic causes of premature coronary artery disease (pCAD).

RECENT FINDINGS

pCAD refers to coronary artery disease (CAD) occurring before the age of 65 years in women and 55 years in men. Both genetic and non-genetic risk factors may contribute to the onset of pCAD. Recent advances in the genetic epidemiology of pCAD have revealed the importance of both monogenic and polygenic contributions to pCAD. Familial hypercholesterolemia (FH) is the most common monogenic disorder associated with atherosclerotic pCAD. However, clinical overreliance on monogenic genes can result in overlooked genetic causes of pCAD, especially polygenic contributions. Non-genetic factors, notably smoking and drug use, are also important contributors to pCAD. Cigarette smoking has been observed in 25.5% of pCAD patients relative to 12.2% of non-pCAD patients. Finally, myocardial infarction (MI) associated with spontaneous coronary artery dissection (SCAD) may result in similar clinical presentations as atherosclerotic pCAD. Recognizing the genetic and non-genetic causes underlying pCAD is important for appropriate prevention and treatment. Despite recent progress, pCAD remains incompletely understood, highlighting the need for both awareness and research.

Calibrated rare variant genetic risk scores for complex disease prediction using large exome sequence repositories

Rare variants are collectively numerous and may underlie a considerable proportion of complex disease risk. However, identifying genuine rare variant associations is challenging due to small effect sizes, presence of technical artefacts, and heterogeneity in population structure. We hypothesize that rare variant burden over a large number of genes can be combined into a predictive rare variant genetic risk score (RVGRS). We propose a method (RV-EXCALIBER) that leverages summary-level data from a large public exome sequencing database (gnomAD) as controls and robustly calibrates rare variant burden to account for the aforementioned biases. A calibrated RVGRS strongly associates with coronary artery disease (CAD) in European and South Asian populations by capturing the aggregate effect of rare variants through a polygenic model of inheritance. The RVGRS identifies 1.5% of the population with substantial risk of early CAD and confers risk even when adjusting for known Mendelian CAD genes, clinical risk factors, and a common variant genetic risk score.

IL17RA in early-onset coronary artery disease: Total leukocyte transcript analysis and promoter polymorphism (rs4819554) association

BACKGROUND AND AIMS

The interleukin-17 (IL-17) pathway would play an important role in the pathogenesis of atherosclerosis and coronary-artery disease (CAD). The IL-17 inflammatory mediators are expressed by Th17 cells, a group of CD4 + leukocytes that infiltrate the vascular milieu and are pivotal in the origin, progression, stability and rupture of the atherosclerotic lesion. Cigarette smoke compounds stimulated the expression of IL-17 and IL-17-receptors. In atherogenic mice models the deficiency of IL-17RA resulted in a reduction of the atherosclerotic lesion size and leukocyte infiltrate. We hypothesised that common the IL-17RA transcript might be differential expressed in the leukocytes from CAD patients and healthy individuals.

METHODS

The relative amount of the IL-17RA to ACTB transcript was determined in total leukocytes of 55 patients and 50 controls, all smokers. We genotyped the IL-17RA rs48195554 promoter polymorphisms in 390 healthy controls and 450 early-onset CAD patients.

RESULTS

Patients showed significantly higher mean IL-17RA normalised transcript value than controls (p < 0.001). For the IL-17RA rs48195554 promoter polymorphisms, IL-17RA G-carriers showed higher transcript values. However, allele and genotype frequencies did not differ between patients and controls and we thus excluded a significant association with CAD.

CONCLUSIONS

The higher levels of the IL-17RA transcript among CAD-patients was in agreement with a role for the IL-17 pathway in the pathogenesis of coronary atherosclerosis.

Premature Atherosclerotic Cardiovascular Disease: What Have We Learned Recently?

PURPOSE OF REVIEW

In contrast to patients with non-premature atherosclerotic cardiovascular disease (ASCVD), patients with premature ASCVD have not observed a similar decline in cardiovascular mortality and recurrent adverse events. We sought to review the underlying risk factors, potential gaps in medical management, associated outcomes, and tools for risk prognostication among patients with premature ASCVD.

RECENT FINDINGS

In addition to traditional cardiovascular risk factors (i.e., diabetes, familial hypercholesterolemia), non-traditional risk factors such as chronic inflammatory conditions, recreational drug use, genetics, and pregnancy-related complications play a key role in development and progression of premature ASCVD. Patients with premature ASCVD, and especially women, receive less optimal medical management as compared to their non-premature counterparts. There is an increasing prevalence of cardiovascular risk factors among young adults. Hence, this population remains at an elevated risk for premature ASCVD and subsequent adverse cardiovascular events. Future studies evaluating different risk assessment tools and focusing on young patients across all three major domains of ASCVD are needed.

Conventional and Complementary Healthcare Utilization Among US Adults With Cardiovascular Disease or Cardiovascular Risk Factors: A Nationally Representative Survey

Background

Cardiovascular diseases (CVDs) and their risk factors need guideline‐oriented treatment to provide the best benefit for patients. These guidelines include recommendations for regular checkups, realized by general medical practitioners. In addition, individuals with CVD or CVD risk factors tend to use complementary methods for their condition. There is limited information on the association between complementary healthcare utilization and the adherence to recommended conventional health care.

Methods and Results

In this cross‐sectional analysis of the nationally representative 2017 National Health Interview Survey (n=26 742; response rate 80.7%) we examined the prevalence of conventional and complementary healthcare utilization within the past 12 months in individuals with CVD and/or CVD risk factors and the interactions between the two categories of health care. Of all participants, 38.1% reported risk factors for CVD and 11.4% a CVD diagnosis (groups show an overlap). Overall prevalence of visits to conventional and complementary medicine providers and the use of mind–body medicine was high within the population analyzed. Individuals with CVD and/or CVD risk factors using complementary health care were as likely or more likely to consult general practitioners (CVD: adjusted odds ratio [aOR], 1.17; 95% CI, 0.93–1.47; CVD risk: aOR, 1.21; 95% CI, 1.05–1.39) and medical specialists (CVD: aOR, 1.38; 95% CI, 1.17–1.64; CVD risk: aOR, 1.42; 95% CI, 1.28–1.58) than those not using complementary health care. Those using complementary health care were as likely to adhere to medical checkup as those not using complementary health care.

Conclusions

Complementary healthcare utilization use was not associated with a reduced adherence to conventional health care and recommended checkups. The potential positive association of complementary and conventional healthcare utilization needs to be confirmed in further studies.