Kullo, Iftikhar J.

Background: Familial hypercholesterolemia (FH) is an important public health burden as it is a relatively common Mendelian genetic disorder which is associated with dramatically increased lifetime risk for premature atherosclerotic cardiovascular disease (ASCVD) due to elevated plasma low-density lipoprotein cholesterol (LDL-C) levels. Little is known about prevalence and control of FH in the US. Objective: To develop an electronic phenotyping algorithm for rapid identification of FH in electronic health records (EHRs) and thereby address knowledge gaps in prevalence and control of FH. Methods: We identified patients in the Mayo Employee and Community Health (ECH) system who met the following inclusion criteria: 1) gave research authorization, 2) any LDL-C in EHR ≥190 mg/dL; 2) triglycerides <400 mg/dL; 3) absence of secondary causes of hyperlipidemia (hypothyroidism, cholestatic liver diseases, nephrotic syndrome, renal failure, and pregnancy). Next we applied the Dutch Lipid Clinic Network (DLCN) criteria to ascertain FH cases. ASCVD-related diagnosis codes, laboratory data, and medications were obtained from structured EHR datasets. We used the Mayo natural language processing (NLP) system to ascertain presence of family and personal history of premature ASCVD, xanthomas and corneal arcus from clinical text notes. Results: Of a total of 131,000 patients seen in ECH clinics between July 1993 and December 2014, 6018 met the inclusion criteria. Implementing the electronic phenotyping algorithm for FH in these patients identified 178 definite and 369 probable cases (DLCN score >8 and 6-8 points, respectively) with an overall FH prevalence of 0.4% (1:240). Blinded expert review of 160 randomly chosen patients showed positive and negative predictive values for electronic phenotyping algorithm at 85% and 90%, respectively. Only 40% of these patients achieved LDL-C ≤100 mg/dL on treatment. Conclusions: 1) An EHR-based phenotyping algorithm that included NLP had reasonable accuracy in ascertaining FH cases. 2) Implementing this algorithm revealed the prevalence of FH in the study cohort to be nearly twice the current estimate of 1:500 in the general population. 3) Less than half of the FH patients had optimal LDL-C levels on treatment.

Background: Compared to those with natural nocturnal blood pressure (BP) decreases, those lacking nocturnal BP decreases (“non-dippers”) are at greater risk of cardiovascular disease (CVD). Substantial evidence also supports a role of chronic systemic inflammation in the pathogenesis of CVD. The purpose of this study was to examine associations of markers of inflammation with two common definitions of BP dipping status using 24-hour ambulatory blood pressure (AMBP) readings. Methods: AMBP monitoring and assays of C-reactive protein (CRP), interleukin-6 (IL-6), e-selectin, tissue inhibitor of metalloproteinase-2 (TIMP-2), and a selection of thirteen other inflammatory-pathway biomarkers were performed in 722 participants (mean age 64 [range 42-83] years, 36% men, 39% black, 83% hypertensive) in the Genetic Epidemiology Network of Arteriopathy (GENOA) Study (2001-2004). Non-dippers were classified using two common definitions: (1) nocturnal systolic and diastolic BP both decreased by <10% compared to daytime values [“dual non-dippers”, n=161 (22%)], and (2) nocturnal SBP decreased by <10% [“systolic non-dippers”, n=380 (53%)]. Logistic regressions, fit with generalized estimating equations to account for sibship clustering, yielded odds ratios (OR) of dipping status for log-transformed inflammatory biomarkers, adjusted for age, race, and sex. Results: IL-6 (range 0-37 pg/ml) was associated with dual non-dipping status (OR=1.55 [95%CI: 1.03, 2.32] p=0.035), translating into a 55% increase in the likelihood of being a dual non-dipper for every approximate doubling of IL-6. IL-6 (OR=1.63 [1.13, 2.35] p=0.009) and CRP (OR=1.35 [1.08,1.68] p=0.008) overall, as well as e-selectin (OR=0.49 [0.28, 0.87] p=0.014) and TIMP-2 (OR=0.54 [0.30,0.98] p=0.041) in hypertensive subjects were associated with systolic non-dipping status. Conclusions: These results suggest that non-dipping classification should be approached with prudence, as the two different criteria may influence conclusions about predictive marker associations. In addition, markers involved in direct versus inhibitory inflammation pathways may operate differentially across patient subgroups. Our findings support the link between inflammation and non-dipping circadian BP patterns and provide novel information on markers and definitions which may be useful for early detection and subsequent prevention of CVD.

Background: Genome-wide association studies (GWAS) have identified several common variants associated with abdominal aortic aneurysm (AAA). We investigated whether a multi-locus genetic risk score (GRS) for AAA was associated with presence and progression of AAA in a case-control study. Methods: The study comprised of 1098 patients with AAA (74±8 years, 83% men) and 6538 controls (67±10 years, 58% men) enrolled in the Mayo Vascular Disease Biorepository. AAA was defined as a transverse diameter of abdominal aorta ≥ 3.0 cm or history of AAA repair. Controls were participants without known AAA. We found five single nucleotide polymorphisms (SNPs) previously shown to be associated with AAA at GWAS significance (P≤10^-8) in NHGRI GWAS catalog and PubMed. A GRS for AAA for each individual was calculated from four SNPs (rs2383107, rs7025486, rs599839, rs1466535) that were replicated in our cohort, by summing the number of risk alleles for each SNP weighted by their estimated effect sizes in GWAS catalog or published largest meta-analysis. Results: GRS was associated with presence of AAA: odds ratio (OR) (95% confidence interval): 1.06 (1.03-1.08). The association remained significant after adjustment for age, sex, cardiovascular risk factors, and atherosclerotic cardiovascular diseases: adjusted OR: 1.05 (1.03-1.08). Further adjustment for each SNP did not attenuate association of GRS with presence of AAA (All P<0.001). GRS was not associated with family history of aortic aneurysm (P=0.4). Adding GRS to conventional risk factors improved net reclassification index by 16% (P<0.001).In a subset of patients with AAA who had sequential imaging studies (n=628), GRS was associated with AAA growth rate ≥ 1.75 mm/year (median of the cohort) after adjustment for baseline AAA size: adjusted OR: 1.07 (1.00-1.14). No conventional risk factors were associated with AAA growth. Patients with GRS > 5.24 (median of the cohort) had 1.31 times higher odds of having AAA and 1.64 times higher odds of having AAA growth rate ≥1.75 mm/year compared to those with GRS ≤ 5.24 (both P≤0.005). Conclusions: A multi-locus GRS was associated with presence of AAA and aneurysm growth, suggesting genetic predisposition to disease initiation and progression.

Background The association between the 9p21-3 locus and coronary heart disease (CHD) is well known. We performed a systematic review of the literature to assess whether this locus was associated with severity of coronary atherosclerosis. Data Sources Multiple relevant electronic databases were searched through September 2012 for English language studies with comparative design. Data extraction We tested the association of the 9p21-3 locus: 1) measures of severity of coronary atherosclerosis [number of diseased vessels, Gensini Score, Duke CHD Prognostic Index (Dc.PI)]. 2) angiographic outcomes [change in minimum lumen diameter ([[Unable to Display Character: &#8710;]]MLD) and number of new lesions at follow-up] and 3) key clinical outcomes (all-cause mortality, recurrent myocardial infarction and need for coronary revascularization). Genotypes were classified either as homozygous low risk (Lo) or homozygous high risk (Hi). Data Synthesis Relative risks (RR) were pooled using the random effects model. Seventeen distinct data sets that included 15,826 participants were analyzed. Ten studies (n=9807) reported number of diseased vessels at baseline. Hi genotype was associated with a 33.7% increased risk of triple vessel disease (95% CI 1.08-1.65; p=0.01). The Hi genotype was associated 0.27 higher baseline Gensini Score (95% CI 0.04-0.48; p=0.01) in 3787 individuals. The locus was not associated with Dc.PI [RR=0.21 (95% CI -0.14-0.55; p=0.25)]. The high risk genotype did not predict [[Unable to Display Character: &#8710;]]MLD or number of new lesions at follow-up. There was no difference between Hi and Lo genotypes in terms of all-cause mortality [RR=1.13 (95%CI 0.90-1.41;p=0.28)], recurrent myocardial infarction (95%CI 0.92-1.40; p=0.24) or frequency of coronary revascularization [RR=1.101 95% CI (0.78-1.57); p=0.56]. Conclusion An association between 9p21-3 and greater baseline severity of coronary atherosclerosis was seen in this meta-analysis. However no association was seen between 9p21-3 and adverse angiographic and clinical outcomes which may be due to diminishing genetic risk following dietary modification and statin therapy.

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.

Background Hypertriglyceridemia is associated with increased risk of coronary heart disease but the association is often attributed to concomitant metabolic abnormalities. We investigated the epidemiology of primary isolated hypertriglyceridemia (PIH) and associated cardiovascular risk in a population‐based setting. Methods and Results We identified adults with at least one triglyceride level ≥500 mg/dL between 1998 and 2015 in Olmsted County, Minnesota. We also identified age‐ and sex‐matched controls with triglyceride levels <150 mg/dL. There were 3329 individuals with elevated triglyceride levels; after excluding those with concomitant hypercholesterolemia, a secondary cause of high triglycerides, age <18 years or an incomplete record, 517 patients (49.4±14.0 years, 72.0% men) had PIH (triglyceride 627.6±183.6 mg/dL). The age‐ and sex‐adjusted prevalence of PIH in adults was 0.80% (0.72–0.87); the diagnosis was recorded in 60%, 46% were on a lipid‐lowering medication for primary prevention and a triglyceride level <150 mg/dL was achieved in 24.1%. The association of PIH with coronary heart disease was attenuated but remained significant after adjustment for demographic, socioeconomic, and conventional cardiovascular risk factors (hazard ratio [HR], 1.53; 95% CI, 1.06‐2.20; P = 0.022). There was no statistically significant association between PIH and cerebrovascular disease (HR, 1.06; 95% CI, 0.65‐1.73, P = 0.813), peripheral artery disease (HR, 1.27; 95% CI, 0.43‐3.75; P = 0.668), or the composite end point of all 3 (HR, 1.28; 95% CI, 0.92‐1.80; P =0.148) in adjusted models. Conclusions PIH was associated with incident coronary heart disease events (although there was attenuation after adjustment for conventional risk factors), supporting a causal role for triglycerides in coronary heart disease. The condition is relatively prevalent but awareness and control are low.

There is a need for multimodal strategies to keep research participants informed about study results. Our aim was to characterize preferences of genomic research participants from two institutions along four dimensions of general research result updates: content, timing, mechanism, and frequency. Methods: We conducted a web-based cross-sectional survey that was administered from 25 June 2018 to 5 December 2018. Results: 397 participants completed the survey, most of whom (96%) expressed a desire to receive research updates. Preferences with high endorsement included: update content (brief descriptions of major findings, descriptions of purpose and goals, and educational material); update timing (when the research is completed, when findings are reviewed, when findings are published, and when the study status changes); update mechanism (email with updates, and email newsletter); and update frequency (every three months). Hierarchical cluster analyses based on the four update preferences identified four profiles of participants with similar preference patterns. Very few participants in the largest profile were comfortable with budgeting less money for research activities so that researchers have money to set up services to send research result updates to study participants. Conclusion: Future studies may benefit from exploring preferences for research result updates, as we have in our study. In addition, this work provides evidence of a need for funders to incentivize researchers to communicate results to participants.

Introduction: Functional annotation of rare variants is key to the implementation of genomic medicine. We used molecular dynamics (MD) simulations to assess functional consequences of putative pathogenic variants (PVs) in the low-density lipoprotein receptor gene ( LDLR ). LDLR has a multidomain structure with seven LA repeats and local interactions between these repeats influence ligand binding. However, binding and recycling of the receptor-ligand complex require global changes in conformation. Using MD, we investigated the effects of PVs on long-range dynamics and LDL binding. Methods: An LA 4-6 repeat structure was created from a crystal structure of the extracellular domain (PDB: 1N7D). Structures were solvated with a water box containing TIP3P water molecules and simulated using the AMBER software package with the ff14SB forcefield. The wild type (WT) structure was first relaxed using MD; and subsequently PVs D245Y, F181Y and F181G were modeled. Dynamics were simulated for approximately one microsecond. Values for LDL binding for each PV were obtained from a prior study which used a radioisotope uptake assay. Results: WT domains demonstrated a stable conformation based on root mean square deviation. PVs disrupted the normal distribution in all domains significantly (p < 0.0001), broadening it and introducing multiple peaks. Projection along the top principal components (PCs) showed global destabilization with all PVs. The variant with the greatest impact on LDL binding, F181G, adopted a distinct alternate conformation. Comparison between PV and WT subspaces from PCA correlated with LDL binding (R 2 = 0.99, exponential regression). Structural analysis revealed that the LA5 calcium cage is involved in inter-domain salt bridges, which are disrupted in simulations of PVs. Conclusion: MD simulation of LA4-6 repeats in LDLR suggests PVs alter long-range conformational dynamics, and that such dynamics correlate with LDL binding. The impact of PVs on conformational dynamics and binding may be through disruption of interdomain salt bridges that are mediated by the acidic calcium cage. This study demonstrates the potential utility of MD simulations to functionally characterize LDLR variants.

Introduction: Current risk equations for coronary heart disease (CHD) do not take into account family history or cumulative exposure to LDL-C. We modified CHD risk equations for use in familial hypercholesterolemia (FH) patients and developed a decision aid (DA) for FH to facilitate shared decision making (SDM). Methods: Literature review, evidence synthesis and expert input were used to adapt the 30-year Framingham Risk Score (FRS) and 10-year ACC/AHA pooled cohort equations to calculate the CHD risk in individuals with FH aged 20-39 years and ≥40 years, respectively. Based on published data, estimated risk was multiplied by 2 for family history of early CHD or 3 in the presence of a pathogenic variant. Treatment benefit of lipid lowering was estimated based on the ‘cumulative exposure to LDL-C’ model ( JACC 2012; 60 ) using the following equations: Post-treatment 30-yr risk in those aged 20-39 years = Baseline Risk (FRS) x 0.54 delta LDL-C (mmol/L) Post-treatment 10-yr risk in those aged ≥40 years = Baseline Risk (ACC/AHA Pooled Cohort) x 0.72 delta LDL-C (mmol/L) To convey CHD risk and treatment benefit, we developed a DA using an iterative, patient-centered design process for use in FH encounters. Results: Using the DA, providers can discuss baseline CHD risk estimates, lipid lowering drug (LLD) options and the expected post-treatment risk reduction with FH patients. The estimated % LDL-C reduction for each LLD and the predicted risk reduction per mmol/L of LDL-C lowered were obtained from literature review. Lowering LDL-C by 1 mmol/L (39 mg/dL) was associated with a 28% CHD risk reduction over 10 years and a 46% reduction over 30 years ( Eur Heart J 2017; 38 ). We describe 2 examples of estimating CHD risk and treatment benefit in FH cases in Table 1 . Conclusion: We adapted CHD risk prediction equations to account for family history of CHD and presence of a pathogenic FH variant and designed a DA to convey personalized CHD risk estimates and treatment benefit to facilitate SDM with FH patients.

Background: The pathophysiology of lipoprotein (a) [Lp(a)] remains obscure. We conducted a phenome wide analysis study (PheWAS) to identify pleiotropic effects of LPA variants. Methods: Among 51,843 European-ancestry participants (age 58±16 years, 54% female) of the electronic MEdical Records and Genomics (eMERGE) network we assessed whether LPA variants exhibited pleiotropic affects through an electronic health record-based PheWAS. We adjusted significant associations by presence of atherosclerotic cardiovascular disease (ASCVD; defined as a composite of coronary heart disease, cerebrovascular disease, and peripheral artery disease) to determine whether those associations were independent of ASCVD. Results: In PheWAS analysis, we tested 864 phecodes with 36 independent LPA variants. We identified 21 significant associations with non-ASCVD phenotypes including heart failure, aortic valve stenosis, and chronic kidney disease of which 14 were replicated across independent cohorts. The strength of associations between the LPA variant rs10455872 and both heart failure and aortic valve stenosis related phecodes were significantly attenuated after adjustment for ASCVD. However, the association with chronic kidney disease phecode remained independent following adjustment for ASCVD without any attenuation in the estimated odds ratio (Table). Conclusions: LPA genetic variants were associated with aortic valve stenosis, heart failure and chronic kidney disease. The observed association of LPA variant rs10455872 with aortic stenosis and heart failure appear to be partially mediated by ASCVD, while the association with chronic kidney disease appears to be independent of ASCVD. Additional studies are needed to elucidate potential mechanisms by which Lp(a) may contribute to the pathogenesis of non-ASCVD disease phenotypes.