Austin, Erin

Background: Atherosclerotic cardiovascular disease (ASCVD) often affects > 1 arterial location (polyvascular disease, PVD). The risk of adverse outcomes increases with the number of arterial territories involved. The genetic susceptibility to PVD is unknown. Hypothesis: We hypothesized that a genetic risk score representing cumulative effects of susceptibility variants to ASCVD is associated with presence of PVD. Methods: We searched genome-wide association study (GWAS) catalog to identify genetic variants associated with coronary heart disease (CHD), ischemic stroke, peripheral arterial disease (PAD) or abdominal aortic aneurysm (AAA). No variants were reported to be associated with PVD in ≥ 3 arterial territories at GWAS significance. 10 loci were associated with PVD in 2 arterial territories. We calculated a multi-locus GRS using 10 lead single nuclear polymorphisms (SNP) from these distinct loci (1 per each loci) in 7486 participants in Mayo Vascular Disease Biorepository (age 68±10 years, 61% men, 31% with CHD; 27% carotid artery stenosis; 39% PAD; 14% AAA; 38% without any of these vascular diseases). Results: Of all participants 34% had PVD (2%, 10% and 22% with exact 4, 3 and 2 arterial territories involved respectively). A higher GRS was associated with greater number of arterial territories involved (P for trend of ANOVA <0.001). Patients with PVD in ≥ 3 arterial locations had higher GRS compared to those with 2 arterial locations involved after adjustment for age, sex and cardiovascular risk factors (P =0.008). One unit increase in GRS was associated with 9% higher likelihood for each additional arterial territory involved after adjustment for all covariates (odds ratio from ordinal regression model= 1.09, P <0.001). The result remained significant after further adjustment for combinations of AAA, CHD, carotid arterial stenosis and PAD (all P ≤ 0.01). 5 Of the 10 SNPs were each associated with presence of PVD after adjustment for all covariates (all P <0.01). None of them remained significant after further adjustment for combinations of PVD in different arterial territories (all P ≥ 0.4). Conclusions: A GRS derived from 10 SNPs of ASCVD is associated with PVD,suggesting genetic contribution to the dimension of PVD that may lead to adverse outcome.

Introduction: Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death worldwide. The genetic contribution to mortality in patients with ASCVD is unknown. Hypothesis: Abdominal aortic aneurysm (AAA) often co-exists with ASCVD and two with shared genetic susceptibility underlying disease development. We hypothesiz that a genetic risk score (GRS) for susceptibility variants to AAA and ASCVD increases the risk for all-cause mortality in patients with ASCVD. Methods: We analyzed high-density genotyping data in 3053 participants (age 71 ±10 years, 72% men) with ASCVD in Mayo Vascular Disease Biorepository. We used 4 single nucleotide polymorphisms (SNPs) (rs2383207, rs7025486, rs599839, rs1466535) previously shown to be associated with AAA and ASCVD at GWAS significance (P ≤10^-8) in the NHGRI GWAS catalog to build the GRS. We defined ASCVD as a history of myocardial infarction / coronary revascularization / ischemic stroke / peripheral arterial disease with revascularization. Results: Patients with GRS > median level had similar age (70±10 vs. 71±10), prevalence of men (72% vs. 73%), hypertension (83% vs. 82%), diabetes (32% vs. 31%) and smokers (74% vs. 72%) compared to those with GRS ≤ median (all P>0.2), except for dyslipidemia (91% vs. 88%, P =0.02). After a median follow-up of 4.56 years (interquartile: 3.07-6.26), 620 patients died. Patients with GRS > median had poorer survival compared to those with GRS ≤ median (Figure: Kaplan-Meier curve); and with 23% higher risk for death after adjustment for age, sex and cardiovascular risk factors (hazard ratio HR, 95% CI: 1.23, 1.05-1.45). The association of GRS with all-cause mortality remained significant after excluding patients with known AAA (n=672) (HR, 95%CI: 1.22, 1.01-1.48). Conclusions: A GRS for susceptibility variants of AAA and ASCVD is a prognostic marker in patients with ASCVD.

Background: Peripheral artery disease (PAD) affects >200 million people worldwide and is associated with high mortality and morbidity. We sought to identify genomic variants associated with PAD overall and in the contexts of diabetes and smoking status. Methods: We identified genetic variants associated with PAD and then meta-analyzed with published summary statistics from the Million Veterans Program and UK Biobank to replicate their findings. Next, we ran stratified genome-wide association analysis in ever smokers, never smokers, individuals with diabetes, and individuals with no history of diabetes and corresponding interaction analyses, to identify variants that modify the risk of PAD by diabetic or smoking status. Results: We identified 5 genome-wide significant ( P association ≤5×10 −8 ) associations with PAD in 449 548 (N cases =12 086) individuals of European ancestry near LPA (lipoprotein [a]), CDKN2BAS1 (CDKN2B antisense RNA 1), SH2B3 (SH2B adaptor protein 3) - PTPN11 (protein tyrosine phosphatase non-receptor type 11), HDAC9 (histone deacetylase 9), and CHRNA3 (cholinergic receptor nicotinic alpha 3 subunit ) loci (which overlapped previously reported associations). Meta-analysis with variants previously associated with PAD showed that 18 of 19 published variants remained genome-wide significant. In individuals with diabetes, rs116405693 at the CCSER1 (coiled-coil serine rich protein 1 ) locus was associated with PAD (odds ratio [95% CI], 1.51 [1.32–1.74], P diabetes =2.5×10 −9 , P interactionwithdiabetes =5.3×10 −7 ). Furthermore, in smokers, rs12910984 at the CHRNA3 locus was associated with PAD (odds ratio [95% CI], 1.15 [1.11–1.19], P smokers =9.3×10 −10 , P interactionwithsmoking =3.9×10 −5 ). Conclusions: Our analyses confirm the published genetic associations with PAD and identify novel variants that may influence susceptibility to PAD in the context of diabetes or smoking status.

Background: Whether disclosing genetic risk for coronary heart disease (CHD) to individuals influences information seeking and information sharing is not known. Methods: The myocardial infarction genes (MI-GENES) trial randomized participants aged 45-65 years who were at intermediate risk for CHD based on conventional risk factors and not on statins, to receive their conventional risk score (CRS) or their CRS plus a genetic risk score (GRS) based on 28 susceptibility variants. CHD risk was disclosed by a genetic counselor and then discussed with a physician. Surveys to assess information seeking (including internet use and accessing electronic health records (EHR)) were completed before and three and six months after risk disclosure. Information sharing parameters were assessed after risk disclosure. We assessed whether these behaviors differed by GRS disclosure, or by high (≥1.1) or low (<1.1) GRS. Adjustments were made for age, sex, family history of CHD, baseline CRS and GRS, and education. Results were reported as the mean difference (and standard error) in the score for each survey response between the GRS and CRS participants, with significance determined by regression analysis. Results: GRS participants accessed their EHR to obtain information related to their CHD risk more than CRS participants (0.14 ± 0.06, p=0.03). Overall internet use (0.61 ± 0.23, p=0.01), as well as internet use to seek information about heart disease (0.14 ± 0.06, p=0.02) and how genetic factors affect risk of having a heart attack (0.23 ± 0.07, p=0.002), was significantly higher in the GRS participants. GRS participants shared information about heart attack risk with others (0.35 ± 0.13, p=0.007), particularly family members (0.1 ± 0.04, p=0.02), (V4: 0.10 ± 0.05, p=0.05), and their primary care provider (V4: 0.15 ± 0.07, p=0.03) more than CRS participants. Internet use, EHR access, and information sharing did not differ significantly between the high and low GRS groups. Conclusions: Disclosure of GRS for CHD resulted in greater information seeking (including internet use and EHR access) and information sharing by study participants. Disclosure of genetic risk for CHD may help advance patient engagement in precision medicine.

Fibromuscular dysplasia (FMD) is a nonatherosclerotic vascular disease leading to arterial stenosis, aneurysm and dissection, mainly in renal and carotid arteries. FMD has higher prevalence in females (80-90%) and is associated with hypertension and stroke. The pathophysiology of FMD is unclear and a genetic origin is suspected. We performed a genetic association study in European ancestry individuals. The discovery included 249 cases and 689 controls, in which we analyzed ∼26K common variants (MAF>0.05) using an exome-chip array. We followed up 13 loci (P<10-4) in 393 cases and 2537 controls and replicated a signal on Chr6. Three additional studies (combined Ncases=512, Ncontrols=669) confirmed this association, with an overall OR of 1.39, (P=7.4х10e-10 , All Ncases=1154, All Ncontrols=3895). The FMD risk variant is intronic to the phosphatase and actin regulator 1 gene (PHACTR1), involved in angiogenesis and cell migration. PHACTR1 is a risk locus for coronary artery disease, migraine, and cervical artery dissection, which may occur in FMD. We found a significant association between the risk allele and higher central pulse pressure (P=0.0009), increased intima media thickness (P=0.001) and wall cross-sectional area (P=0.003) of carotids assessed by echotracking in 3800 population-based individuals. The correlation of genotypes with the expression of PHACTR1 in primary cultured human fibroblasts showed higher expression in FMD risk allele carriers, compared to non carriers (N=57, P=0.02). Finally, Phactr1 knockdown of zebrafish showed significantly dilated vessels (P=0.003) indicating impaired vascular development. In conclusion, we report the first risk locus for FMD with the largest genetic association study conducted so far. Our data reveal a common genetic variant at PHACTR1 providing indices of shared pathophysiology between FMD and other cardiovascular and neurovascular diseases.

Background: Abdominal aortic aneurysm (AAA) is a complex and heterogeneous disorder. We hypothesized that dense phenomapping using electronic health records (EHR) can identify subtypes of AAA with distinct clinical and genetic characteristics. Methods & Results: AAA cases (n=1108) and controls (n=4694) were identified from the Mayo vascular disease biorepository and had available high-density genotyping data. 132 Candidate genetic variants (p < 10E-5) associated with atherosclerotic cardiovascular disease (ASCVD) or AAA were selected from GWAS catalog. Using model-based Gaussian-mixture cluster analysis of 46 clinical features from 6 data domains, 24 data elements, 204 variables (including age, sex, vital signs, laboratory data, medication use, family history), spanning over 20 years of observational time in the EHR, we identified two subtypes of AAA: subtype 1(S1, n=421) with faster AAA growth rate (baseline size adjusted mean difference, 95% CI: 0.013, 0.001 to 0.020 cm / year faster, p = 0.03), higher all-cause mortality (age & sex adjusted hazard ratio, 95% CI: 1.36, 1.09 - 1.70, p < 0.01) than subtype 2 (S2, n=687). As compared with the controls, thyroid disorder / rheumatoid or osteoarthritis / infectious conditions were uniquely associated with increased odds ratio for S1; ASCVD / hyperlipidemia / hypertension were uniquely associated with increased odds ratio for S2. After adjustment for all group-specific diseases, genetic variants in CDKN2B-AS1, NOA1-REST, ERG, ZNF335-MMP9 and SMAD3 were associated with S1 and variants in MMP12, DAB2IP, LHFPL2, LPA, FSTL5 and SORT1 were associated with S2 (all FDR p < 0.05). After adjustment for disease comorbidities and genetic variants differently associated with S1 and S2, the increased risk for all-cause death of S1 than S2 and the difference in AAA expansion rate in subgroups attenuated (Both p-values > 0.09) Conclusions: We identified two subtypes of AAA with different rates of aneurysm expansion and all-cause mortality, which were associated with subtype-specific disease comorbidities and genetic markers, suggesting the potential of leveraging EHR to facilitate individualized medicine in patients with AAA.

Objective— It is unclear to what extent genetic susceptibility variants are shared between peripheral artery disease (PAD) and coronary heart disease (CHD), both manifestations of atherosclerotic vascular disease. We investigated whether common and low-frequency/rare variants in loci associated with CHD are also associated with PAD. Approach and Results— Targeted sequencing of 41 genomic regions associated with CHD in genome-wide association studies was performed in 1749 PAD cases (65±11 years, 61% men) and 1855 controls (60±11 years, 56% men) of European ancestry. PAD cases had a resting/postexercise ankle-brachial index ≤0.9, or history of lower extremity revascularization; controls had no history of PAD. We tested the association of common (defined as minor allele frequency ≥5%) variants with PAD assuming an additive genetic model with adjustment for age and sex. To identify low-frequency/rare variants (minor allele frequency <5%) associated with PAD, we conducted gene-level analyses using sequence kernel association test and permutation test. After Bonferroni correction, we found common variants in SH2B3, ABO , and ZEB2 to be associated with PAD ( P <4.5×10 −5 ). At the gene level, the strongest associations were for LPL and SH2B3 . Conclusions— Targeted sequencing of 41 genomic regions associated with CHD revealed several common variants/genes to be associated with PAD, highlighting the basis of shared genetic susceptibility between CHD and PAD.

A faster expansion rate of abdominal aortic aneurysm (AAA) increases the risk of rupture. Women are at higher risk of rupture than men, but the mechanisms underlying this increased risk are unknown. We investigated whether genetic variants that influence susceptibility for AAA ( CDKN2A-2B, SORT1, DAB2IP, LRP1 and LDLR) are associated with AAA expansion and whether these associations differ by sex in 650 patients with AAA (mean age 70±8 years, 17% women) enrolled in the Mayo Clinic Vascular Disease Biorepository. Women had a mean aneurysm expansion 0.41 mm/year greater than men after adjustment for baseline AAA size. In addition to baseline size, mean arterial pressure (MAP), non-diabetic status, SORT1-rs599839[G] and DAB2IP-rs7025486[A] were associated with greater aneurysm expansion (all p<0.05). The associations of MAP and rs599839[G] were similar in both sexes, while the associations of baseline size, pulse pressure (PP) and rs7025486[A] were stronger in women than men (all p - sex interaction ≤0.02). A three-way interaction of PP*sex* rs7025486[A] was noted in a full-factorial analysis (p=0.007) independent of baseline size and MAP. In the high PP group (≥median), women had a mean growth rate 0.68 mm/year greater per [A] of rs7025486 than men (p - sex interaction =0.003), whereas there was no difference in the low PP group (p - sex interaction =0.8). We demonstrate that variants DAB2IP-rs7025486[A] and SORT1-rs599839[G] are associated with AAA expansion. The association of rs7025486[A] is stronger in women than men and amplified by high PP, contributing to sex differences in aneurysm expansion.

AbstractLittle is known about individuals’ motivation, perception, and treatment beliefs towards the use of genetic information in risk estimates for coronary heart disease (CHD). In this study, participants at intermediate 10‐year risk of CHD were randomized to receive either their estimated conventional risk score (CRS) alone, or a CRS and a genetic risk score (GRS), by a genetic counselor. Surveys on motivation to participate in and perception of genetic testing for CHD were administered at 3 months and treatment beliefs at 6 months following risk disclosure. Survey responses used Likert scales. Linear and logistic regression were used for analysis. Overall, motivation to participate in genomic clinical trials was favorable and did not differ between the CRS and GRS groups (16.95 ± 0.82 vs. 17.58 ± 0.83, p = 0.091), but participants who initially received their GRS indicated a greater desire to find ways to improve health as a reason for participation (OR: 0.53 (95%CI: 0.29, 0.94), p = 0.028). Perception of genetic testing was also favorable in both groups (15.29 ± 0.39 vs. 15.12 ± 0.40, p = 0.835). Participants who initially received their GRS were more inclined to recommend genetic testing to family and friends (9.95 ± 1.88 vs. 10.52 ± 2.17, p = 0.023). In the MI‐GENES study, motivation to participate in and perception of genetic testing among study participants were overall favorable. Genetic risk disclosure was associated with increased motivation to recommend genetic testing to family and friends.