Influence of Polygenic Background on the Clinical Presentation of Familial Hypercholesterolemia.

BACKGROUND: Heterozygous familial hypercholesterolemia (FH) is among the most common genetic conditions worldwide that affects ≈ 1 in 300 individuals. FH is characterized by increased levels of low-density lipoprotein cholesterol (LDL-C) and increased risk of coronary artery disease (CAD), but there is a wide spectrum of severity within the FH population. This variability in expression is incompletely explained by known risk factors. We hypothesized that genome-wide genetic influences, as represented by polygenic risk scores (PRSs) for cardiometabolic traits, would influence the phenotypic severity of FH. METHODS: We studied individuals with clinically diagnosed FH (n=1123) from the FH Canada National Registry, as well as individuals with genetically identified FH from the UK Biobank (n=723). For all individuals, we used genome-wide gene array data to calculate PRSs for CAD, LDL-C, lipoprotein(a), and other cardiometabolic traits. We compared the distribution of PRSs in individuals with clinically diagnosed FH, genetically diagnosed FH, and non-FH controls and examined the association of the PRSs with the risk of atherosclerotic cardiovascular disease. RESULTS: Individuals with clinically diagnosed FH had higher levels of LDL-C, and the incidence of atherosclerotic cardiovascular disease was higher in individuals with clinically diagnosed compared with genetically identified FH. Individuals with clinically diagnosed FH displayed enrichment for higher PRSs for CAD, LDL-C, and lipoprotein(a) but not for other cardiometabolic risk factors. The CAD PRS was associated with a risk of atherosclerotic cardiovascular disease among individuals with an FH-causing genetic variant. CONCLUSIONS: Genetic background, as expressed by genome-wide PRSs for CAD, LDL-C, and lipoprotein(a), influences the phenotypic severity of FH, expanding our understanding of the determinants that contribute to the variable expressivity of FH. A PRS for CAD may aid in risk prediction among individuals with FH.

Obicetrapib on top of maximally tolerated lipid-modifying therapies in participants with or at high risk for atherosclerotic cardiovascular disease: rationale and designs of BROADWAY and BROOKLYN.

BACKGROUND: Obicetrapib, a novel, selective cholesteryl ester transfer protein (CETP) inhibitor, reduces low-density lipoprotein cholesterol (LDL-C), LDL particles, apolipoprotein (Apo) B, and lipoprotein(a) [Lp(a)] and increases high-density lipoprotein cholesterol (HDL-C) when added to statins with or without ezetimibe. By substantially reducing LDL-C, obicetrapib has the potential to lower atherogenic lipoproteins in patients with atherosclerotic cardiovascular disease (ASCVD) or heterozygous familial hypercholesterolemia (HeFH) whose LDL-C levels remain high despite treatment with available maximally tolerated lipid-modifying therapies, addressing an unmet medical need in a patient population at high risk for cardiovascular events. METHODS AND RESULTS: BROADWAY (NCT05142722) and BROOKLYN (NCT05425745) are ongoing placebo-controlled, double-blind, randomized Phase III trials designed to examine the efficacy, safety, and tolerability of obicetrapib as an adjunct to dietary intervention and maximally tolerated lipid-modifying therapies in participants with a history of ASCVD and/or underlying HeFH whose LDL-C is not adequately controlled. The primary efficacy endpoint was the percent change in LDL-C from baseline to day 84. Other endpoints included changes in Apo B, non-HDL-C, HDL-C, Apo A1, Lp(a), and triglycerides in addition to parameters evaluating safety, tolerability, and pharmacokinetics. BROADWAY also included an adjudicated assessment of major adverse cardiovascular events, measurements of glucose homeostasis, and an ambulatory blood pressure monitoring substudy. A total of 2,532 participants were randomized in BROADWAY and 354 in BROOKLYN to receive obicetrapib 10 mg or placebo (2:1) for 365 days with follow-up through 35 days after the last dose. Results from both trials are anticipated in 2024. CONCLUSION: These trials will provide safety and efficacy data to support the potential use of obicetrapib among patients with ASCVD or HeFH with elevated LDL-C for whom existing therapies are not sufficiently effective or well-tolerated.

Familial hypercholesterolemia-Plus: is the metabolic syndrome changing the clinical picture of familial hypercholesterolemia?

PURPOSE OF REVIEW: The purpose of this review article was to describe recent advances in our knowledge about how diabetes and metabolic syndrome are changing the face of familial hypercholesterolemia. RECENT FINDINGS: Heterozygous familial hypercholesterolemia, most commonly caused by disruption to LDL receptor function, leads to lifelong elevation of LDL cholesterol and increased risk of atherosclerotic cardiovascular disease. Familial hypercholesterolemia was originally described as a form of 'pure' hypercholesterolemia, in the sense that levels of LDL were uniquely affected. Studies of familial hypercholesterolemia among individuals of predominantly Western European descent conformed to the perception that individuals with familial hypercholesterolemia tended to be lean and otherwise metabolically healthy. More recently, as we have studied familial hypercholesterolemia in more diverse global populations, we have learned that in some regions, rates of diabetes and obesity among familial hypercholesterolemia patients are very high, mirroring the global increases in the prevalence of metabolic disease. SUMMARY: When diabetes and metabolic disease coexist, they amplify the cardiovascular risk in familial hypercholesterolemia, and may require more aggressive treatment.

Prevalence of Dysbetalipoproteinemia in the UK Biobank According to Different Diagnostic Criteria.

CONTEXT: Dysbetalipoproteinemia (DBL) is a multifactorial disorder that disrupts the normal metabolism of remnant lipoproteins, causing increased risk of cardiovascular disease. However, establishing a proper diagnosis is difficult and the true prevalence of the disease in the general population remains unknown. OBJECTIVE: The objectives were to study the prevalence of the disease and to validate the performance of different clinical diagnostic criteria in a large population-based cohort. METHODS: This study included 453 437 participants from the UK Biobank. DBL was established in participants having an ε2ε2 genotype with mixed dyslipidemia or lipid-lowering therapy use (n=964). The different diagnostic criteria for DBL were applied in individuals without lipid-lowering medication (n=370 039, n=534 DBL), to compare their performance. RESULTS: Overall, 0.6% of participants had an ε2ε2 genotype, of which 36% were classified as DBL, for a disease prevalence of 0.2% (1:469). The prevalence of DBL was similar between the different genetic ancestries (≤0.2%). Several diagnostic criteria showed good sensitivity for the diagnosis of DBL (>90%), but they suffered from a very low positive predictive value (0.6%-15.4%). CONCLUSION: This study reported for the first time the prevalence of DBL in the UK Biobank according to genetic ancestry. Furthermore, we provided the first external validation of different diagnostic criteria for DBL in a large population-based cohort and highlighted the fact that these criteria should not be used to diagnose DBL alone but should rather be used as a first screening step to determine which individuals may benefit from genetic testing to confirm the diagnosis.

CETP inhibition enhances monocyte activation and bacterial clearance and reduces streptococcus pneumonia-associated mortality in mice.

Sepsis is a leading cause of mortality worldwide, and pneumonia is the most common cause of sepsis in humans. Low levels of high-density lipoprotein cholesterol (HDL-C) levels are associated with an increased risk of death from sepsis, and increasing levels of HDL-C by inhibition of cholesteryl ester transfer protein (CETP) decreases mortality from intraabdominal polymicrobial sepsis in APOE*3-Leiden.CETP mice. Here, we show that treatment with the CETP inhibitor (CETPi) anacetrapib reduced mortality from Streptococcus pneumoniae-induced sepsis in APOE*3-Leiden.CETP and APOA1.CETP mice. Mechanistically, CETP inhibition reduced the host proinflammatory response via attenuation of proinflammatory cytokine transcription and release. This effect was dependent on the presence of HDL, leading to attenuation of immune-mediated organ damage. In addition, CETP inhibition promoted monocyte activation in the blood prior to the onset of sepsis, resulting in accelerated macrophage recruitment to the lung and liver. In vitro experiments demonstrated that CETP inhibition significantly promoted the activation of proinflammatory signaling in peripheral blood mononuclear cells and THP1 cells in the absence of HDL; this may represent a mechanism responsible for improved bacterial clearance during sepsis. These findings provide evidence that CETP inhibition represents a potential approach to reduce mortality from pneumosepsis.

The Importance of Nontraditional and Sex-Specific Risk Factors in Young Women With Vasomotor Nonobstructive vs Obstructive Coronary Syndromes.

Background: Heart disease is the leading cause of premature death for women in Canada. Ischemic heart disease is categorized as myocardial infarction (MI) with no obstructive coronary artery disease (MINOCA), ischemia with no obstructive coronary arteries (INOCA), and atherosclerotic obstructive coronary artery disease (CAD) with MI (MI-CAD) or without MI (non-MI-CAD). This study aims to study the prevalence of traditional and nontraditional ischemic heart disease risk factors and their relationships with (M)INOCA, compared to MI-CAD and non-MI-CAD in young women. Methods: This study investigated women who presented with premature (at age ≤ 55 years) vasomotor entities of (M)INOCA or obstructive CAD confirmed by coronary angiography, who are currently enrolled in either the Leslie Diamond Women's Heart Health Clinic Registry (WHC) or the Study to Avoid Cardiovascular Events in British Columbia (SAVEBC). Univariable and multivariable regression models were applied to investigate associations of risk factors with odds of (M)INOCA, MI-CAD, and non-MI-CAD. Results: A total of 254 women enrolled between 2015 and 2022 were analyzed, as follows: 77 with INOCA and 37 with MINOCA from the registry, and 66 with non-MI-CAD and 74 with MI-CAD from the study. Regression analyses demonstrated that migraines and preeclampsia or gestational hypertension were the most significant risk factors, with a higher likelihood of being associated with premature (M)INOCA, relative to obstructive CAD. Conversely, the presence of diabetes and a current or previous smoking history had the highest likelihood of being associated with premature CAD. Conclusions: The risk factor profiles of patients with premature (M)INOCA, compared to obstructive CAD, have significant differences.

Contexte: Au Canada, la cardiopathie est la principale cause de décès prématuré chez les femmes. La cardiopathie ischémique est catégorisée comme suit : infarctus du myocarde (IM) en l'absence de coronaropathie obstructive (MINOCA), ischémie sans obstruction des artères coronaires (INOCA) et athérosclérose coronaire obstructive accompagnée d'un IM ou sans IM. La présente étude vise à examiner la prévalence des facteurs de risque classiques et non classiques de cardiopathie ischémique et leurs liens avec le (M)INOCA, comparativement à l'athérosclérose coronaire obstructive accompagnée d'un IM ou sans IM chez les femmes jeunes. Méthodologie: Cette étude portait sur des femmes qui avaient prématurément (55 ans ou moins) souffert d'un (M)INOCA ou d'une coronaropathie obstructive confirmés par coronarographie et qui étaient inscrites au registre de la Leslie Diamond Women's Heart Health Clinic (WHC) ou qui participaient à l'étude visant à éviter les événements cardiovasculaires en Colombie-Britannique (Study toAvoid CardiovascularEvents inBC; SAVEBC). Des modèles de régression univariés et multivariés ont été utilisés pour explorer les associations entre les facteurs de risque et les probabilités de (M)INOCA, ainsi que d'athérosclérose coronaire obstructive accompagnée ou non d'un IM. Résultats: Au total, 254 femmes inscrites de 2015 à 2022 ont été recensées, soit 77 présentant une INOCA et 37, un MINOCA selon le registre WHC, et 66 présentant une athérosclérose coronaire obstructive sans IM et 74, une athérosclérose coronaire obstructive accompagnée d'un IM selon l'étude SAVEBC. Les analyses de régression ont démontré que les migraines et la prééclampsie ou l'hypertension gestationnelle étaient les facteurs de risque les plus importants associés à une probabilité la plus élevée de (M)INOCA comparativement à une coronaropathie obstructive. En revanche, la présence d'un diabète et d'un tabagisme actuel ou passé était associée à la probabilité la plus élevée de coronaropathie prématurée. Conclusions: Il existe d'importantes différences pour ce qui est des profils de facteurs de risque des patientes ayant prématurément souffert d'un (M)INOCA en comparaison d'une coronaropathie obstructive.

Sex differences in the presentation, treatment and outcomes of patients with homozygous familial hypercholesterolemia.

BACKGROUND: Homozygous familial hypercholesterolemia (HoFH) is a rare, autosomal semi-dominant lipid metabolism disorder characterized by extremely high low-density lipoprotein cholesterol (LDL-C) levels and premature cardiovascular disease. The objective of this study was to investigate sex-differences in the treatment and outcomes of patients with HoFH. METHODS: We examined clinical characteristics, lipid-lowering therapy (LLT), and cardiovascular events using descriptive statistics of patients in the Canadian HoFH registry. Major adverse cardiovascular events (MACE) were defined as the composite of cardiovascular death, non-fatal myocardial infarction, and stroke. Sex differences between continuous and categorical variables were analyzed using Mann-Whitney U test and Fisher's Exact test, respectively. RESULTS: This study included 48 patients (27 (56%) female). The median age at diagnosis in females was 14.0 (interquartile range (IQR) 9.0-30.0) and in males was 8.0 (IQR 2.0-23.0) (p = 0.07). Baseline clinical characteristics were comparable between both sexes. The median baseline LDL-C was 12.7 mmol/L (10.0-18.3) in females and 15.3 (10.5-20.0) in males (p = 0.51). Follow up LDL-C levels were 7.6 mmol/L (IQR 4.8-11.0) in females and 6.3 (IQR 4.6-7.5) in males (p = 0.1). Most patients were taking 3 or more LLTs, with comparable proportions in both sexes (p = 0.26). Apheresis was similar in both sexes, 14 (51.8%) vs. 10 (47.6%) (p = 0.2). Over a mean of 10 years of follow-up, MACE occurred in 3 females (11.1%) and 4 males (19.1%) (p = 0.2). CONCLUSION: Lipid levels and treatment were similar between sexes. MACE occurred in similar proportions between sexes, indicating that HoFH offsets the inherently lower cardiovascular risk in pre-menopausal females. Further investigation into sex-differences in HoFH in larger sample sizes is warranted.

Recommendations for statin management in primary prevention: disparities among international risk scores.

BACKGROUND AND AIMS: Statin recommendations in primary prevention depend upon risk algorithms. Moreover, with intermediate risk, risk enhancers and de-enhancers are advocated to aid decisions. The aim of this study was to compare algorithms used in North America and Europe for the identification of patients warranting statin or consideration of risk enhancers and de-enhancers. METHODS: A simulated population (n = 7680) equal in males and females, with/without smoking, aged 45-70 years, total cholesterol 3.5-7.0 mmol/L, high-density lipoprotein cholesterol 0.6-2.2 mmol/L, and systolic blood pressure 100-170 mmHg, was evaluated. High, intermediate, and low risks were determined using the Framingham Risk Score (FRS), Pooled Cohort Equation (PCE), four versions of Systematic Coronary Risk Evaluation 2 (SCORE2), and Multi-Ethnic Study of Atherosclerosis (MESA) algorithm (0-1000 Agatston Units). RESULTS: Concordance for the three levels of risk varied from 19% to 85%. Both sexes might be considered to have low, intermediate, or high risk depending on the algorithm applied, even with the same burden of risk factors. Only SCORE2 (High Risk and Very High Risk versions) identified equal proportions of males and females with high risk. Excluding MESA, the proportion with moderate risk was 25% (SCORE2, Very High Risk Region), 32% (FRS), 39% (PCE), and 45% (SCORE2, Low Risk Region). CONCLUSION: Risk algorithms differ substantially in their estimation of risk, recommendations for statin treatment, and use of ancillary testing, even in identical patients. These results highlight the limitations of currently used risk-based approaches for addressing lipid-specific risk in primary prevention.

Increased FH-Risk-Score and Diabetes Are Cardiovascular Risk Equivalents in Heterozygous Familial Hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH) is a genetic condition causing premature atherosclerotic cardiovascular disease (ASCVD). It is well established that patients with FH should be treated with statin therapy. However, there exists discordance concerning low-density lipoprotein cholesterol-lowering goals in the management of these patients between different guidelines worldwide. The objective was to compare the 10-year ASCVD risk of different subgroups of patients with and without FH including those with diabetes or a history of ASCVD and patients with FH within different FH-Risk-Score categories. METHODS: This multinational observational study used data from 3 different prospective cohorts. A total of 3383 FH and 6917 non-FH controls matched for age and sex were included (104 363 person-years of follow-up). The 10-year incident ASCVD risk was assessed using Kaplan-Meier estimates, whereas the relative risk was estimated using Cox proportional hazards regression models. RESULTS: FH patients with a high (score >20%) FH-Risk-Score (hazard ratio, 8.45 [95% CI, 6.69-10.67]; P<0.0001), FH patients with diabetes (hazard ratio, 7.67 [95% CI, 4.82-12.21]; P<0.0001), and non-FH patients with ASCVD (hazard ratio, 6.78 [95% CI, 5.45-8.42]; P<0.0001) had a significantly higher incident ASCVD risk over 10 years than the reference group (non-FH without ASCVD or diabetes). The observed 10-year risks in these groups were 32.1%, 30.8%, 30.0%, and 5.1%, respectively. The 10-year ASCVD risk associated with both FH and ASCVD was extremely high (observed risk of 50.7%; hazard ratio, 14.53 [95% CI, 12.14-17.38]; P<0.0001). CONCLUSIONS: This study strongly suggests that the observed risk of FH patients with diabetes, history of ASCVD, and FH-Risk-Score >20% is as high or higher than non-FH individuals with a history of ASCVD. More aggressive management should be recommended for these patients.

Sex differences in the perception of cardiovascular risk in familial hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH), a common genetic condition, is characterized by elevated low-density lipoprotein cholesterol (LDL-C) and premature atherosclerotic cardiovascular disease (ASCVD). Recent data indicate an undertreatment of females with FH. OBJECTIVE: To characterize the role of sex in the perception of FH, its associated ASCVD risk and treatment. METHODS: A survey investigating for sex differences in the perception of FH was sent to 1073 patients with FH using a cross sectional study design. RESULTS: A total of 412 patients (51.9 % male) responded to the survey; mean age was 56.2 ± 14.4 years. There was a higher proportion of males with ASCVD than females (41.5 % vs. 16.5 %, respectively, p<0.001). Analyses of the survey responses showed that a majority of both males and females agreed that their risk of ASCVD is higher than healthy individuals of same age (70.8 % vs. 74.7 %, respectively, p = 0.434). Females were more concerned about having high LDL-C levels (67.5 % vs. 56.5 % in males, p = 0.024), especially those in secondary prevention programs. As for treatment of FH, approximately 75 % of both sex groups considered statins to be efficient in reducing the risk of myocardial infarction, but less than half of the females considered statins to be safe (44.8 % vs. 60.0 % in males, p = 0.003). No major sex differences were noted regarding the influence of the doctor in their understanding of FH as a disease. CONCLUSION: Overall, both males and females with FH were well informed about FH, although females were more concerned about having high LDL-C levels and they feared the safety of statins.

Genome-wide association meta-analysis of spontaneous coronary artery dissection identifies risk variants and genes related to artery integrity and tissue-mediated coagulation.

Spontaneous coronary artery dissection (SCAD) is an understudied cause of myocardial infarction primarily affecting women. It is not known to what extent SCAD is genetically distinct from other cardiovascular diseases, including atherosclerotic coronary artery disease (CAD). Here we present a genome-wide association meta-analysis (1,917 cases and 9,292 controls) identifying 16 risk loci for SCAD. Integrative functional annotations prioritized genes that are likely to be regulated in vascular smooth muscle cells and artery fibroblasts and implicated in extracellular matrix biology. One locus containing the tissue factor gene F3, which is involved in blood coagulation cascade initiation, appears to be specific for SCAD risk. Several associated variants have diametrically opposite associations with CAD, suggesting that shared biological processes contribute to both diseases, but through different mechanisms. We also infer a causal role for high blood pressure in SCAD. Our findings provide novel pathophysiological insights involving arterial integrity and tissue-mediated coagulation in SCAD and set the stage for future specific therapeutics and preventions.

Metabolic syndrome predicts cardiovascular risk and mortality in familial hypercholesterolemia.

BACKGROUND: The association between familial hypercholesterolemia (FH) and premature atherosclerotic cardiovascular disease (ASCVD) is well established. Several risk factors other than the cumulative low-density lipoprotein cholesterol (LDL-C) have been shown to modulate the severity of the phenotype in these patients. However, the effect of the metabolic syndrome (MetS) on ASCVD risk in FH remains to be determined. OBJECTIVES: The objective was to study the association between the presence of MetS and the incidence of different ASCVD endpoints and all-cause mortality. METHODS: This prospective follow up study used data from 5 independent FH cohorts from Europe and North America. We analysed data of 2401 adult heterozygous FH without history of a prior ASCVD event (21,139 person-years of follow-up). Multivariate Cox proportional hazards regression was used to estimate the association between MetS and the incidence of the different endpoints. RESULTS: The prevalence of MetS was 14% in the study population. The presence of MetS was a significant predictor of incident 10-year ASCVD after adjustment for traditional cardiovascular risk factors (HR 2.07, 95% CI 1.34-3.19), as well as of 10-year major adverse cardiovascular event (MACE) (HR 4.59, 95% CI 2.27-9.30), 10-year myocardial infarction (MI) (HR 4.29, 95% CI 1.91-9.63), and 30-year all-cause mortality (HR 4.87, 95% CI 1.99-11.89). CONCLUSION: Our findings suggests that FH patients with MetS, have an increased cardiovascular risk that is independent from LDL-C and other traditional risk factors. Future studies are required to determine the most appropriate strategy to reduce the cardiovascular burden associated with MetS in this population.

Genetic Identification of Homozygous Familial Hypercholesterolemia by Long-Read Sequencing Among Patients With Clinically Diagnosed Heterozygous Familial Hypercholesterolemia.

BACKGROUND: Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disorder characterized by extremely elevated plasma low-density lipoprotein cholesterol and accelerated atherosclerosis. Accurate identification of patients with HoFH is essential as they may be eligible for specialized treatments. We hypothesized that a subset of patients with clinically diagnosed heterozygous FH (HeFH) may in fact have HoFH, and this could be identified by genetic diagnosis. METHODS: We recruited patients with a clinical diagnosis of HeFH based on a Dutch Lipid Clinic Network score ≥6 and no secondary cause of hypercholesterolemia. We performed targeted next-generation sequencing of the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and low-density lipoprotein receptor adapter protein 1 (LDLRAP1) genes, followed by long-read sequencing of the LDLR gene in patients with >1 pathogenic LDLR variant. We examined lipid levels and cardiovascular events. RESULTS: Among 705 patients with clinically diagnosed HeFH, we identified a single pathogenic variant in 300 (42.6%) and >1 pathogenic variant in the LDLR gene in 11 patients (1.6%). We established a genetic diagnosis of HoFH in 6 (0.9%) patients (3 true homozygotes and 3 compound heterozygotes). The mean baseline low-density lipoprotein cholesterol and prevalence of premature cardiovascular disease of patients with genetically identified HoFH was significantly higher than patients with HeFH. CONCLUSIONS: In a cohort of patients with clinically diagnosed HeFH, genetic testing including long-read sequencing revealed that 0.9% had HoFH. These patients tended to have a more severe clinical phenotype. Genetic testing of patients with clinical FH may identify patients with HoFH that had eluded clinical diagnosis.

Longitudinal Control of Lipid Levels in Patients With Premature Coronary Artery Disease.

Background: Lipid-lowering therapy (LLT) is a central aspect of the treatment of patients with coronary artery disease (CAD), and the benefits of LLT accrue over time. However, there are limited real-world data on longitudinal lipid control in patients with premature CAD. Objectives: The purpose of this study was to assess longitudinal attainment of guideline-recommended lipid goals and outcomes in a contemporary cohort of patients with premature CAD. Methods: We enrolled males younger than 50 years and females younger than 55 years with coronary stenosis of >50% and examined achievement of lipid goals, LLT characteristics, and cardiovascular outcomes (major adverse cardiovascular event [MACE]). Results: Of 476 patients who presented with acute coronary syndrome (ST-elevation myocardial infarction, non-ST-segment elevation myocardial infarction, unstable angina) (68%), stable angina (28%), or other symptoms, 73.2% achieved low-density lipoprotein cholesterol (LDL-C) <1.8 mmol/L on at least 1 occasion, but only 27.3% consistently stayed in the target range for 3 years after diagnosis. Although 73.9% of patients received high-intensity LLT at the time of diagnosis, only 43.5% had good adherence over the following 3 years. In multivariable analysis, 1 mmol/L increase in time-weighted average exposure to LDL-C, but not the lowest achieved LDL-C, was associated with a higher risk of MACE, hazard ratio 2.02 (95% CI: 1.48-2.76), when adjusted for sex, age, hypertension, diabetes, and smoking. Conclusions: We found low rates of longitudinal lipid target achievement in patients with premature CAD. Cumulative LDL-C exposure, but not lowest achieved LDL-C, was associated with risk of MACE. This highlights the critical importance of longitudinal control of lipids levels and identifies opportunities to improve LLT and maximize the time-dependent benefits of lipid-lowering.

Homozygous Familial Hypercholesterolemia in Canada: An Observational Study.

Background: Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disease characterized by very high levels of low-density lipoprotein cholesterol (LDL-C). Untreated patients present with extensive xanthomas and premature atherosclerosis. Lipid-lowering therapy is highly efficacious and has dramatically increased life expectancy of patients with HoFH. Objectives: The aim of the study was to obtain a comprehensive registry of HoFH in Canada, known to have several founder effect regions, and describe the clinical characteristics and cardiovascular outcomes of this population over time. Methods: Clinical and genetic data on patients with HoFH were collected via a standardized questionnaire sent to academic sites participating in the Familial Hypercholesterolemia Canada network. Results: A total of 48 patients with HoFH were enrolled. The median age at diagnosis was 12 years (interquartile range [IQR]: 5-24) and untreated LDL-C levels were 15.0 mmol/L (IQR: 10.5-18.6 mmol/L; 580 mg/dL IQR: 404-717 mg/dL). At last follow-up visit, median age was 40 years (IQR: 26-54 years). Treated LDL-C levels were 6.75 mmol/L (IQR: 4.73-9.51 mmol/L; 261 mg/dL IQR: 183-368 mg/dL) with 95.5% of patients on statins, 88.6% on ezetimibe, 34.1% on proprotein convertase subtilisin/kexin type 9 inhibitors, 27.3% on lomitapide, 13.6% on evinacumab, and 56.8% were treated with low-density lipoprotein apheresis or plasmapheresis. Deaths were reported in 7 (14.5%) and major adverse cardiovascular events were observed in 14.6% of patients with the average onset at 30 years (IQR: 20-36 years). Aortic stenosis was reported in one-half the patients (47.9%) and 10 (20.8%) underwent aortic valve replacement. Conclusions: This HoFH patient registry in Canada will provide important new health-related knowledge about the phenotypic manifestations and determinants of cardiovascular risk in this population, allowing for closer examination of quality of life and burden to the health care system.

Estimating the Prevalence of Hypercholesterolemia in Indigenous Populations: A Systematic Review and Meta-Analysis.

Background: Hypercholesterolemia is a common condition characterized by elevated levels of low-density lipoprotein cholesterol (LDL-C) and increased risk of atherosclerotic cardiovascular disease (ASCVD). Indigenous populations experience disproportionate rates of ASCVD, however, the extent to which hypercholesterolemia contributes to this burden is unknown. Objectives: This study aimed to estimate the prevalence of hypercholesterolemia, severe hypercholesterolemia, and familial hypercholesterolemia (FH) in Indigenous populations in Canada, the United States, Australia, and New Zealand. Methods: We searched MEDLINE, EMBASE, Web of Science, Native Health Database, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews for peer-reviewed studies reporting on hypercholesterolemia and elevated LDL-C in Indigenous populations. All diagnostic criteria used to classify hypercholesterolemia were included. Pooled prevalence and 95% CIs were calculated using a random-effects model. Results: There were no studies reporting the prevalence of FH and one study reporting the prevalence of severe hypercholesterolemia in Indigenous populations. The pooled prevalence of hypercholesterolemia was 28.9% or ∼1 in 3 to 1 in 4 individuals (95% CI: 22.4%-36.4%) and 12.6% (95% CI: 7.7%-19.9%) using an LDL-C cutoff of ≥3.5 mmol/L (135 mg/dL). The pooled prevalence in Indigenous populations in North America was 24.3% (95% CI: 17.1%-33.3%) compared with 40.0% (95% CI: 31.3%-49.3%) in Australia. Meta-regression showed diabetes had a significant effect on prevalence (P = 0.022). Conclusions: Hypercholesterolemia is prevalent in Indigenous communities and may contribute to the high burden of ASCVD these populations face. There is insufficient research on FH and severe hypercholesterolemia in Indigenous populations worldwide.

Burden of Rare Genetic Variants in Spontaneous Coronary Artery Dissection With High-risk Features.

Importance: The emerging genetic basis of spontaneous coronary artery dissection (SCAD) has been defined as both partially complex and monogenic in some patients, involving variants predominantly in genes known to underlie vascular connective tissue diseases (CTDs). The effect of these genetic influences has not been defined in high-risk SCAD phenotypes, and the identification of a high-risk subgroup of individuals may help to guide clinical genetic evaluations of SCAD. Objective: To identify and quantify the burden of rare genetic variation in individuals with SCAD with high-risk clinical features. Design, Setting, and Participants: Whole-exome sequencing (WES) was performed for subsequent case-control association analyses and individual variant annotation among individuals with high-risk SCAD. Genetic variants were annotated for pathogenicity by in-silico analysis of genes previously defined by sequencing for vascular CTDs and/or SCAD, as well as genes prioritized by genome-wide association study (GWAS) and colocalization of arterial expression quantitative trait loci. Unbiased genome-wide association analysis of the WES data was performed by comparing aggregated variants in individuals with SCAD to healthy matched controls or the Genome Aggregation Database (gnomAD). This study was conducted at a tertiary care center. Individuals in the Canadian SCAD Registry genetics study with a high-risk SCAD phenotype were selected and defined as peripartum SCAD, recurrent SCAD, or SCAD in an individual with family history of arteriopathy. Main Outcomes and Measures: Burden of genetic variants defined by DNA sequencing in individuals with high-risk SCAD. Results: This study included a total of 336 participants (mean [SD] age, 53.0 [9.5] years; 301 female participants [90%]). Variants in vascular CTD genes were identified in 17.0% of individuals (16 of 94) with high-risk SCAD and were enriched (OR, 2.6; 95% CI, 1.6-4.2; P = 7.8 × 10-4) as compared with gnomAD, with leading significant signals in COL3A1 (OR, 13.4; 95% CI, 4.9-36.2; P = 2.8 × 10-4) and Loeys-Dietz syndrome genes (OR, 7.9; 95% CI, 2.9-21.2; P = 2.0 × 10-3). Variants in GWAS-prioritized genes, observed in 6.4% of individuals (6 of 94) with high-risk SCAD, were also enriched (OR, 3.6; 95% CI, 1.6-8.2; P = 7.4 × 10-3). Variants annotated as likely pathogenic or pathogenic occurred in 4 individuals, in the COL3A1, TGFBR2, and ADAMTSL4 genes. Genome-wide aggregated variant testing identified novel associations with peripartum SCAD. Conclusions and Relevance: In this genetic study, approximately 1 in 5 individuals with a high-risk SCAD phenotype harbored a rare genetic variant in genes currently implicated for SCAD. Genetic screening in this subgroup of individuals presenting with SCAD may be considered.

Effect of the LDL receptor mutation type on incident major adverse cardiovascular events in familial hypercholesterolaemia.

AIMS: Patients with familial hypercholesterolaemia (FH) are at increased risk of cardiovascular disease (CVD) due to extremely high circulating LDL cholesterol (LDL-C) concentrations. Our objective was to study the effect of the type of LDL receptor (LDLR) mutation on the incidence of major adverse cardiovascular events (MACEs). METHODS AND RESULTS: This was a multinational prospective cohort study, which included patients with heterozygous FH aged 18-65 years, without a prior history of CVD, and carrying a pathogenic or likely pathogenic variant in the LDLR gene. A total of 2131 patients (20 535person-years of follow-up) were included in the study, including 1234 subjects carrying a defective mutation in the LDLR and 897 subjects carrying a null mutation. During the follow-up, a first MACE occurred in 79 cases (6%) in the defective group and in 111 cases (12%) in the null group. The mean baseline LDL-C concentration was 17% higher in the null group than in the defective group (7.90 vs. 6.73 mmoL/L, P < 0.0001). In a Cox regression model corrected for traditional cardiovascular risk factors, the presence of a null mutation was associated with a hazard ratio of 2.09 (1.44-3.05), P = 0.0001. CONCLUSION: Carriers of a null mutation have an independent ∼2-fold increased risk of incident MACE compared with patients carrying a defective mutation. This study highlights the importance of genetic screening in FH in order to improve patient care.

RARG S427L attenuates the DNA repair response to doxorubicin in induced pluripotent stem cell-derived cardiomyocytes.

Doxorubicin is a commonly used chemotherapeutic drug, but its use is limited by doxorubicin-induced cardiotoxicity (DIC), which can lead to irreversible heart failure and death. A missense variant rs2229774 (p.S427L) in the retinoic acid receptor gamma (RARG) gene is associated with increased susceptibility to DIC, but the precise mechanism underlying this association is incompletely understood. We performed molecular dynamic simulations to determine the effect of this variant on RARG structure and then validated these predictions using CRISPR-Cas9-genome-edited, induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). We found that this variant leads to reduced activation of its target genes in response to doxorubicin, including gene pathways involved in DNA repair and consequently an inability to mediate DNA repair after exposure to doxorubicin. Our findings establish a role of RARG p.S427L in attenuating DNA repair in DIC and provide insight into the pathogenesis of this cardiotoxic effect.

Polygenic risk scores for the diagnosis and management of dyslipidemia.

PURPOSE OF REVIEW: To review current progress in the use of polygenic risk scores for lipid traits and their use in the diagnosis and treatment of lipid disorders. RECENT FINDINGS: Inherited lipid disorders, including those causing extremes of low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, or triglycerides were initially identified as monogenic traits, in which a single rare variant with large effect size is responsible for the phenotype. More recently, a polygenic basis for many lipid traits has also been identified. Patients with polygenic dyslipidemia can be identified through the use of polygenic risk scores (PRSs), which collapse information from a handful to several million genetic variants into a single metric. SUMMARY: PRSs for lipid traits may aid in the identification of the genetic basis for the lipid phenotype in individual patients, may provide additional information regarding the risk of cardiovascular disease, and could help in guiding therapeutic decision making.