Genetics of coronary artery disease and myocardial infarction.
ABSTRACT: Atherosclerotic coronary artery disease (CAD) comprises a broad spectrum of clinical entities that include asymptomatic subclinical atherosclerosis and its clinical complications, such as angina pectoris, myocardial infarction (MI) and sudden cardiac death. CAD continues to be the leading cause of death in industrialized society. The long-recognized familial clustering of CAD suggests that genetics plays a central role in its development, with the heritability of CAD and MI estimated at approximately 50% to 60%. Understanding the genetic architecture of CAD and MI has proven to be difficult and costly due to the heterogeneity of clinical CAD and the underlying multi-decade complex pathophysiological processes that involve both genetic and environmental interactions. This review describes the clinical heterogeneity of CAD and MI to clarify the disease spectrum in genetic studies, provides a brief overview of the historical understanding and estimation of the heritability of CAD and MI, recounts major gene discoveries of potential causal mutations in familial CAD and MI, summarizes CAD and MI-associated genetic variants identified using candidate gene approaches and genome-wide association studies (GWAS), and summarizes the current status of the construction and validations of genetic risk scores for lifetime risk prediction and guidance for preventive strategies. Potential protective genetic factors against the development of CAD and MI are also discussed. Finally, GWAS have identified multiple genetic factors associated with an increased risk of in-stent restenosis following stent placement for obstructive CAD. This review will also address genetic factors associated with in-stent restenosis, which may ultimately guide clinical decision-making regarding revascularization strategies for patients with CAD and MI.
Project description:Large genome-wide association studies (GWAS) have identified many genetic loci associated with risk for myocardial infarction (MI) and coronary artery disease (CAD). Concurrently, efforts such as the National Institutes of Health (NIH) Roadmap Epigenomics Project and the Encyclopedia of DNA Elements (ENCODE) Consortium have provided unprecedented data on functional elements of the human genome. In the present study, we systematically investigate the biological link between genetic variants associated with this complex disease and their impacts on gene function. First, we examined the heritability of MI/CAD according to genomic compartments. We observed that single nucleotide polymorphisms (SNPs) residing within nearby regulatory regions show significant polygenicity and contribute between 59-71% of the heritability for MI/CAD. Second, we showed that the polygenicity and heritability explained by these SNPs are enriched in histone modification marks in specific cell types. Third, we found that a statistically higher number of 45 MI/CAD-associated SNPs that have been identified from large-scale GWAS studies reside within certain functional elements of the genome, particularly in active enhancer and promoter regions. Finally, we observed significant heterogeneity of this signal across cell types, with strong signals observed within adipose nuclei, as well as brain and spleen cell types. These results suggest that the genetic etiology of MI/CAD is largely explained by tissue-specific regulatory perturbation within the human genome.
Project description:Percutaneous coronary intervention (PCI) with stent placement is a standard treatment for coronary artery disease (CAD). Despite all medical advances, restenosis remains a challenging clinical problem. However, the molecular and biochemical pathways of restenotic process are not fully understood yet. Furthermore, as restenosis is assumed to be a multigenetic process and genetic predisposition is considered an important risk factor, analysis of the genome-wide gene expression is recommended for better insight of the phenomenon. We used microarray technology to monitor thousands of genes expression simultaneously. The whole genome expression will be analyzed with this technique to identify cluster of up-regulated and down-regulated genes which may be involved in this complex pathological condition. Coronary restenosis after percutaneous coronary intervention remains a challenging problem, despite all medical advances. Molecular and biochemical pathways of restenotic process are not fully understood yet. Furthermore, as restenosis is assumed to be a multigenetic process. We used microarray technology to monitor thousands of genes expression simultaneously in restenosis postive group with reference restenosis negative group, which will unravel potentially modifiable pathways, possible targets and biomarkers for coronary restenosis.
Project description:The KBI (kissing balloon inflation) technique is considered the default strategy for the two-stent approach in real world practice. Studies comparing KBI and No-KBI in patients undergoing the one-stent approach have reported conflicting results. The meta-analysis was performed to compare the clinical outcomes of the KBI strategy and the No-KBI strategy for coronary bifurcation lesions in the one-stent approach. Five randomized studies were included, and a total of 1264 patients were involved in the meta-analysis. The primary outcome was cardiac death. The secondary end points were stent thrombosis, MI (myocardial infarction), target lesion revascularization (TLR), target vessel revascularization (TVR), and main vessel and side branch restenosis. Compared with the No-KBI strategy, the KBI strategy was associated with a significant reduction in side branch restenosis (OR: 0.44, 95% CI: 0.30-0.64, p<0.001). A high risk of main vessel restenosis was found in the KBI group (OR: 2.96, 95% CI: 1.74-5.01, p<0.001). There were no significant differences in rates of cardiac death (OR: 1.89, 95% CI: 0.60-5.95, p = 0.28), stent thrombosis (OR: 0.98, 95% CI: 0.19-4.94, p = 0.98), MI (OR: 0.68, 95% CI: 0.33-1.44, p = 0.30), TLR (OR 1.14, 95% CI 0.68-1.90, p = 0.62), or TVR (OR 1.27, 95% CI 0.75-2.16, p = 0.38). Compared with the No-KBI strategy, the KBI strategy reduced the incidence of side branch restenosis and increased the risk of main branch restenosis in the one-stent approach. However, the clinical outcomes were similar between the KBI and No-KBI groups.
Project description:The comparative performance of different drug-eluting stents (DES) among female patients has not been assessed in a randomized manner.The SPIRIT Women Clinical Evaluation trial compared the durable polymer everolimus-eluting XIENCE stent (DP-EES) with the durable polymer sirolimus-eluting Cypher stent (DP-SES) in women undergoing percutaneous coronary intervention (PCI).A total of 455 female patients with stable CAD were randomly assigned to receive DP-EES (n = 304) or DP-SES (n = 151). The powered angiographic outcome of the trial was in-stent late lumen loss (LLL) at 9 months after the index procedure. Secondary angiographic end points included in-segment LLL, in-stent and in-segment binary restenosis and percent diameter stenosis. The primary clinical outcome was a composite of all-cause death, myocardial infarction (MI) or target vessel revascularization (TVR).At 9-month follow-up, in-stent LLL was 0.19±0.38 mm and 0.11±0.37 mm in patients assigned to DP-EES and DP-SES, respectively. The one-sided upper 95% CI of the difference in in-stent LLL between the groups of 0.08 mm was 0.15 and therefore within the pre-specified non-inferiority margin of 0.17 mm (p for non-inferiority = 0.013). However, the test for superiority showed a borderline significant difference in terms of LLL between DP-EES and DP-SES (p for superiority = 0.044). There were no significant differences in binary restenosis (2.0% vs. 0.72%, p = 0.44) and percent diameter stenosis (14.97±12.17 vs. 13.36±10.82, p = 0.19). The rate of definite stent thrombosis at 12 months was lower in patients treated with DP-EES (0% vs. 2.0%, p = 0.036).Among women undergoing PCI, DP-EES was associated with a small but probably clinically relevant increase in in-stent LLL at 9 months as compared to DP-SES and with a lower risk of definite stent thrombosis at 12 months.ClinicalTrials.gov NCT01182428. https://clinicaltrials.gov/.
Project description:<h4>Background</h4>Drug-eluting balloon (DEB) has become an alternative option to drug-eluting stent (DES) for the treatment of in-stent restenosis (ISR). However, the effect of drug-eluting balloon with regular bare-mental stent (BMS) in de novo coronary artery disease (CAD) is unclear. This meta-analysis aimed to evaluate the efficacy of DEB with regular BMS compared to BMS or DES in de novo CAD.<h4>Methods</h4>Randomized controlled trials (RCTs) assessing the efficacy of DEB+BMS in comparison with BMS or DES were obtained by searching the PubMed, EMBASE, and Cochrane Library databases through January 2016. Primary endpoints were major adverse cardiac events (MACEs) and late lumen loss (LLL). Secondary endpoints included death, myocardial infarction (MI), target lesion revascularization (TLR), stent thrombosis (ST), binary restenosis, and minimum lumen diameter (MLD). Dichotomous and continuous data were presented as odds ratios (ORs) and mean differences (MDs) with 95% confidence intervals (CIs), respectively, and analyzed using a random-effects model.<h4>Results</h4>A total of 14 RCTs involving 2281 patients were included in this meta-analysis. DEB+BMS showed significantly less MACEs (OR: 0.67, 95%CI 0.45 to 0.99, P = 0.04) and reduced LLL (MD: -0.30 mm, 95%CI: -0.48 mm to -0.11 mm, P = 0.001) compared with BMS. Meanwhile, treatment with DEB+BMS had disadvantages over DES in terms of MACEs (OR: 1.94, 95%CI 1.24 to 3.05, P = 0.004), LLL (MD: 0.20 mm, 95%CI: 0.07 mm to 0.33 mm, P = 0.003), TLR (OR: 2.53, 95% CI 1.36 to 4.72, P = 0.003), and MLD (MD: -0.25 mm, 95%CI: -0.42 mm to -0.09 mm, P = 0.003).<h4>Conclusions</h4>This limited evidence demonstrated that treatment with DEB+BMS appears to be effective in de novo CAD. In addition, DEB+ BMS clearly showed superiority to BMS, but is inferior to DES in the treatment of patients with de novo CAD. Hence, DES (especially new generation DES) should be recommended for patients with de novo CAD.
Project description:Coronary artery disease (CAD) is the leading cause of death worldwide. Recent genome-wide association studies (GWAS) identified >50 common variants associated with CAD or its complication myocardial infarction (MI), but collectively they account for <20% of heritability, generating a phenomena of "missing heritability". Rare variants with large effects may account for a large portion of missing heritability. Genome-wide linkage studies of large families and follow-up fine mapping and deep sequencing are particularly effective in identifying rare variants with large effects. Here we show results from a genome-wide linkage scan for CAD in multiplex GeneQuest families with early onset CAD and MI. Whole genome genotyping was carried out with 408 markers that span the human genome by every 10 cM and linkage analyses were performed using the affected relative pair analysis implemented in GENEHUNTER. Affected only nonparametric linkage (NPL) analysis identified two novel CAD loci with highly significant evidence of linkage on chromosome 3p25.1 (peak NPL ?=?5.49) and 3q29 (NPL ?=?6.84). We also identified four loci with suggestive linkage on 9q22.33, 9q34.11, 17p12, and 21q22.3 (NPL ?=?3.18-4.07). These results identify novel loci for CAD and provide a framework for fine mapping and deep sequencing to identify new susceptibility genes and novel variants associated with risk of CAD.
Project description:Cardiovascular disease is the dominant cause of mortality in developed countries, with coronary artery disease (CAD) a predominant contributor. The development of stents to treat CAD was a significant innovation, facilitating effective percutaneous coronary revascularization. Coronary stents have evolved from bare metal compositions, to incorporate advances in pharmacological therapy in what are now known as drug eluting stents (DES). Deployment of a stent overcomes some limitations of balloon angioplasty alone, but provides an acute stimulus for thrombus formation and promotes neointimal hyperplasia. First generation DES effectively reduced in-stent restenosis, but profoundly delay healing and are susceptible to late stent thrombosis, leading to significant clinical complications in the long term. This review characterizes the development of coronary stents, detailing the incremental improvements, which aim to attenuate the major clinical complications of thrombosis and restenosis. Despite these enhancements, coronary stents remain fundamentally incompatible with the vasculature, an issue which has largely gone unaddressed. We highlight the latest modifications and research directions that promise to more holistically design coronary implants that are truly biocompatible.
Project description:BACKGROUND:Genetic variants currently known to affect coronary artery disease (CAD) risk explain less than one-quarter of disease heritability. The heritability contribution of gene regulatory networks (GRNs) in CAD, which are modulated by both genetic and environmental factors, is unknown. OBJECTIVES:This study sought to determine the heritability contributions of single nucleotide polymorphisms affecting gene expression (eSNPs) in GRNs causally linked to CAD. METHODS:Seven vascular and metabolic tissues collected in 2 independent genetics-of-gene-expression studies of patients with CAD were used to identify eSNPs and to infer coexpression networks. To construct GRNs with causal relations to CAD, the prior information of eSNPs in the coexpression networks was used in a Bayesian algorithm. Narrow-sense CAD heritability conferred by the GRNs was calculated from individual-level genotype data from 9 European genome-wide association studies (GWAS) (13,612 cases, 13,758 control cases). RESULTS:The authors identified and replicated 28 independent GRNs active in CAD. The genetic variation in these networks contributed to 10.0% of CAD heritability beyond the 22% attributable to risk loci identified by GWAS. GRNs in the atherosclerotic arterial wall (n = 7) and subcutaneous or visceral abdominal fat (n = 9) were most strongly implicated, jointly explaining 8.2% of CAD heritability. In all, these 28 GRNs (each contributing to >0.2% of CAD heritability) comprised 24 to 841 genes, whereof 1 to 28 genes had strong regulatory effects (key disease drivers) and harbored many relevant functions previously associated with CAD. The gene activity in these 28 GRNs also displayed strong associations with genetic and phenotypic cardiometabolic disease variations both in humans and mice, indicative of their pivotal roles as mediators of gene-environmental interactions in CAD. CONCLUSIONS:GRNs capture a major portion of genetic variance and contribute to heritability beyond that of genetic loci currently known to affect CAD risk. These networks provide a framework to identify novel risk genes/pathways and study molecular interactions within and across disease-relevant tissues leading to CAD.
Project description:Obesity is characterized as an excess accumulation of body fat resulting from a positive energy balance. It is the major risk factor for type 2 diabetes (T2D). The evidence for familial aggregation of obesity and its associated metabolic diseases is substantial. To date, about 150 genetic loci identified in genome-wide association studies (GWAS) are linked with obesity and T2D, each accounting for only a small proportion of the predicted heritability. However, the percentage of overall trait variance explained by these associated loci is modest (~5-10% for T2D, ~2% for BMI). The lack of powerful genetic associations suggests that heritability is not entirely attributable to gene variations. Some of the familial aggregation as well as many of the effects of environmental exposures, may reflect epigenetic processes. This review summarizes our current knowledge on the genetic basis to individual risk of obesity and T2D, and explores the potential role of epigenetic contribution.
Project description:Percutaneous coronary intervention (PCI) has become an effective therapy to treat obstructive coronary artery diseases (CAD). However, one of the major drawbacks of PCI is the occurrence of restenosis in 5-25% of all initially treated patients. Restenosis is defined as the re-narrowing of the lumen of the blood vessel, resulting in renewed symptoms and the need for repeated intervention. To identify genetic variants that are associated with restenosis, a genome-wide association study (GWAS) was conducted in 295 patients who developed restenosis (cases) and 571 who did not (controls) from the GENetic Determinants of Restenosis (GENDER) study. Analysis of ~550 000 single nucleotide polymorphisms (SNPs) in GENDER was followed by a replication phase in three independent case-control populations (533 cases and 3067 controls). A potential susceptibility locus for restenosis at chromosome 12, including rs10861032 (P(combined) = 1.11 × 10(-7)) and rs9804922 (P(combined) = 1.45 × 10(-6)), was identified in the GWAS and replication phase. In addition, both SNPs were also associated with coronary events (rs10861032, P(additive) = 0.005; rs9804922, P(additive) = 0.023) in a trial based cohort set of elderly patients with (enhanced risk of) CAD (PROSPER) and all-cause mortality in PROSPER (rs10861032, P(additive) = 0.007; rs9804922, P(additive) = 0.013) and GENDER (rs10861032, P(additive) = 0.005; rs9804922, P(additive) = 0.023). Further analysis suggests that this locus could be involved in regulatory functions.