Absence of Coronary Artery Calcification in Middle-Aged Familial Hypercholesterolemia Patients Without Atherosclerotic Cardiovascular Disease

Subclinical Atherosclerosis to Guide Treatment in Dyslipidemia and Diabetes Mellitus

PURPOSE OF REVIEW

Dyslipidemia and type 2 diabetes mellitus are two common conditions that are associated with an increased risk of atherosclerotic cardiovascular disease (ASCVD). In this review, we aimed to provide an in-depth and contemporary review of non-invasive approaches to assess subclinical atherosclerotic burden, predict cardiovascular risk, and guide appropriate treatment strategies. We focused this paper on two main imaging modalities: coronary artery calcium (CAC) score and computed tomography coronary angiography.

RECENT FINDINGS

Recent longitudinal studies have provided stronger evidence on the relationship between increased CAC, thoracic aorta calcification, and risk of cardiovascular events among those with primary hypercholesterolemia, highlighting the beneficial role of statin therapy. Interestingly, resilient profiles of individuals not exhibiting atherosclerosis despite dyslipidemia have been described. Non-conventional markers of dyslipidemia have also been associated with increased subclinical atherosclerosis presence and burden, highlighting the contribution of apolipoprotein B-100 (apoB)-rich lipoprotein particles, such as remnant cholesterol and lipoprotein(a), to the residual risk of individuals on-target for low-density lipoprotein cholesterol (LDL-C) goals. Regarding type 2 diabetes mellitus, variability in atherosclerotic burden has also been found, and CAC testing has shown significant predictive value in stratifying cardiovascular risk. Non-invasive assessment of subclinical atherosclerosis can help reveal the continuum of ASCVD risk in those with dyslipidemia and diabetes mellitus and can inform personalized strategies for cardiovascular disease prevention in the primary prevention setting.

Beyond early LDL cholesterol lowering to prevent coronary atherosclerosis in familial hypercholesterolaemia

AIMS

Familial hypercholesterolaemia (FH) patients are subjected to a high lifetime exposure to low density lipoprotein cholesterol (LDL-C), despite use of lipid-lowering therapy (LLT). This study aimed to quantify the extent of subclinical atherosclerosis and to evaluate the association between lifetime cumulative LDL-C exposure and coronary atherosclerosis in young FH patients.

METHODS AND RESULTS

Familial hypercholesterolaemia patients, divided into a subgroup of early treated (LLT initiated <25 years) and late treated (LLT initiated ≥25 years) patients, and an age- and sex-matched unaffected control group, underwent coronary CT angiography (CCTA) with artificial intelligence-guided analysis. Ninety genetically diagnosed FH patients and 45 unaffected volunteers (mean age 41 ± 3 years, 51 (38%) female) were included. Familial hypercholesterolaemia patients had higher cumulative LDL-C exposure (181 ± 54 vs. 105 ± 33 mmol/L ∗ years) and higher prevalence of coronary plaque compared with controls (46 [51%] vs. 10 [22%], OR 3.66 [95%CI 1.62-8.27]). Every 75 mmol/L ∗ years cumulative exposure to LDL-C was associated with a doubling in per cent atheroma volume (total plaque volume divided by total vessel volume). Early treated patients had a modestly lower cumulative LDL-C exposure compared with late treated FH patients (167 ± 41 vs. 194 ± 61 mmol/L ∗ years; P = 0.045), without significant difference in coronary atherosclerosis. Familial hypercholesterolaemia patients with above-median cumulative LDL-C exposure had significantly higher plaque prevalence (OR 3.62 [95%CI 1.62-8.27]; P = 0.001), compared with patients with below-median exposure.

CONCLUSION

Lifetime exposure to LDL-C determines coronary plaque burden in FH, underlining the need of early as well as potent treatment initiation. Periodic CCTA may offer a unique opportunity to monitor coronary atherosclerosis and personalize treatment in FH.

Age- and sex-based heterogeneity in coronary artery plaque presence and burden in familial hypercholesterolemia: A multi-national study

Objectives

Individuals with familial hypercholesterolemia (FH) are at an increased risk for coronary artery disease (CAD). While prior research has shown variability in coronary artery calcification (CAC) among those with FH, studies with small sample sizes and single-center recruitment have been limited in their ability to characterize CAC and plaque burden in subgroups based on age and sex. Understanding the spectrum of atherosclerosis may result in personalized risk assessment and tailored allocation of costly add-on, non-statin lipid-lowering therapies. We aimed to characterize the presence and burden of CAC and coronary plaque on computed tomography angiography (CTA) across age- and sex-stratified subgroups of individuals with FH who were without CAD at baseline.

Methods

We pooled 1,011 patients from six cohorts across Brazil, France, the Netherlands, Spain, and Australia. Our main measures of subclinical atherosclerosis included CAC ranges (i.e., 0, 1-100, 101-400, >400) and CTA-derived plaque burden (i.e., no plaque, non-obstructive CAD, obstructive CAD).

Results

Ninety-five percent of individuals with FH (mean age: 48 years; 54% female; treated LDL-C: 154 mg/dL) had a molecular diagnosis and 899 (89%) were on statin therapy. Overall, 423 (42%) had CAC=0, 329 (33%) had CAC 1-100, 160 (16%) had CAC 101-400, and 99 (10%) had CAC >400. Compared to males, female patients were more likely to have CAC=0 (48% [n = 262] vs 35% [n = 161]) and no plaque on CTA (39% [n = 215] vs 26% [n = 120]). Among patients with CAC=0, 85 (20%) had non-obstructive CAD. Females also had a lower prevalence of obstructive CAD in CAC 1-100 (8% [n = 15] vs 18% [n = 26]), CAC 101-400 (32% [n = 22] vs 40% [n = 36]), and CAC >400 (52% [n = 16] vs 65% [n = 44]). Female patients aged 50-59 years were less likely to have obstructive CAD in CAC >400 (55% [n = 6] vs 70% [n = 19]).

Conclusion

In this large, multi-national study, we found substantial age- and sex-based heterogeneity in CAC and plaque burden in a cohort of predominantly statin-treated individuals with FH, with evidence for a less pronounced increase in atherosclerosis among female patients. Future studies should examine the predictors of resilience to and long-term implications of the differential burden of subclinical coronary atherosclerosis in this higher risk population.

Association of cardiometabolic and vascular atherosclerosis phenotypes on non-contrast chest CT with incident heart failure in patients with severe hypercholesterolemia

BACKGROUND

Coronary artery calcium (CAC), thoracic aorta calcification (TAC), non-alcoholic fatty liver disease (NAFLD), and epicardial adipose tissue (EAT) are associated with atherosclerotic cardiovascular disease (ASCVD) and heart failure (HF).

OBJECTIVES

We aimed to determine whether these cardiometabolic and atherosclerotic risk factors identified by non-contrast chest computed tomography (CT) are associated with HF hospitalizations in patients with LDL-C≥ 190 mg/dL.

METHODS

We conducted a retrospective cohort analysis of patients with LDL-C ≥190 mg/dL, aged ≥40 years without established ASCVD or HF, who had a non-contrast chest CT within 3 years of LDL-C measurement. Ordinal CAC, ordinal TAC, EAT, and NAFLD were measured. Kaplan-Meier curves and multivariable Cox regression models were built to ascertain the association with HF hospitalization.

RESULTS

We included 762 patients with median age 60 (53-68) years, 68% (n=520) female, and median LDL-C level of 203 (194-216) mg/dL. Patients were followed for 4.7 (IQR 2.75-6.16) years, and 107 (14%) had a HF hospitalization. Overall, 355 (47%) patients had CAC=0, 210 (28%) had TAC=0, 116 (15%) had NAFLD, and median EAT was 79 mL (49-114). Moderate-Severe CAC (log-rank p<0.001) and TAC (log-rank p=0.006) groups were associated with increased HF hospitalizations. This association persisted when considering myocardial infarction (MI) as a competing risk. NAFLD and EAT volume were not associated with HF.

CONCLUSIONS

In patients without established ASCVD and LDL-C≥190 mg/dL, CAC was independently associated with increased HF hospitalizations while TAC, NAFLD and EAT were not.

Stratification in Heterozygous Familial Hypercholesterolemia: Imaging, Biomarkers, and Genetic Testing

PURPOSE OF REVIEW

Heterozygous familial hypercholesterolemia (HeFH) is the most common monogenic autosomal dominant disorder. However, the condition is often underdiagnosed and undertreated. The objective of this review is to provide an update on the risk stratification in patients with HeFH, incorporating new cardiovascular imaging techniques, various biomarkers, and genetic studies.

RECENT FINDINGS

The diagnosis of HeFH places patients in a high cardiovascular risk category due to the increased incidence of premature atherosclerotic cardiovascular disease. However, the level of risk varies significantly among different individuals with HeFH. Achieving an optimal stratification of cardiovascular risk is crucial for establishing appropriate and accurate treatment and management strategies. Different new tools such as risk scores have emerged in recent years, aiding physicians in assessing the risk stratification for HeFH using imaging, biomarkers, and genetics. This review emphasizes that not all patients with HeFH face the same cardiovascular risk. By utilizing different assessment tools, we can identify those who require more intensive monitoring, follow-up, and treatment.

Assessment of cardiovascular disease risk: a 2023 update

PURPOSE OF REVIEW

The aim of this study was to highlight the current best practice for atherosclerotic cardiovascular disease (CVD) risk evaluation, including selective use of adjunctive tools for risk stratification [e.g. coronary artery calcium (CAC) scoring] and risk enhancement [e.g. lipoprotein(a) [Lp(a)], polygenic risk scoring (PRS)].

RECENT FINDINGS

New studies have evaluated the efficacy of various risk assessment tools. These studies demonstrate the role of Lp(a) as a risk-enhancing factor ready for more widespread use. CAC is the gold standard method of assessing subclinical atherosclerosis, enabling true risk stratification of patients, and informing net benefit assessment for initiating or titrating lipid-lowering therapy (LLT).

SUMMARY

Lp(a) concentration and CAC scoring, apart from the traditional risk factors, add the most value to the current CVD risk assessment approaches of all available tools, especially in terms of guiding LLT. In addition to new integrative tools such as the MESA CHD Risk Score and Coronary Age calculator, the future of risk assessment may include PRS and more advanced imaging techniques for atherosclerosis burden. Soon, polygenic risk scoring may be used to identify the age at which to begin CAC scoring, with CAC scores guiding preventive strategies.

Recent advances in the management and implementation of care for familial hypercholesterolaemia

Familial hypercholesterolaemia (FH) is a common autosomal semi-dominant and highly penetrant disorder of the low-density lipoprotein (LDL) receptor pathway, characterised by lifelong elevated levels of low-density lipoprotein cholesterol (LDL-C) and increased risk of atherosclerotic cardiovascular disease (ASCVD). However, many patients with FH are not diagnosed and do not attain recommended LDL-C goals despite maximally tolerated doses of potent statin and ezetimibe. Over the past decade, several cholesterol-lowering therapies such as those targeting proprotein convertase subtilisin/kexin type 9 (PCSK9) or angiopoietin-like 3 (ANGPTL3) with monoclonal antibody or ribonucleic acid (RNA) approaches have been developed that promise to close the treatment gap. The availability of new therapies with complementary modes of action of lipid metabolism has enabled many patients with FH to attain guideline-recommended LDL-C goals. Emerging therapies for FH include liver-directed gene transfer of the LDLR, vaccines targeting key proteins involved in cholesterol metabolism, and CRISPR-based gene editing of PCSK9 and ANGPTL3, but further clinical trials are required. In this review, current and emerging treatment strategies for lowering LDL-C, and ASCVD risk-stratification, as well as implementation strategies for the care of patients with FH are reviewed.

Coronary Artery Calcium Scoring for Risk Assessment in Patients With Severe Hypercholesterolemia

The American College of Cardiology and the American Heart Association guidelines recommend treatment of patients with severe hypercholesterolemia (low-density lipoprotein cholesterol [LDL-C] ≥190 mg/100 ml) with a high-intensity statin. However, atherosclerotic cardiovascular disease (ASCVD) risk, even among those with severe hypercholesterolemia, is heterogeneous, and coronary artery calcium (CAC) scoring may be used to clarify risk. We sought to evaluate CAC in patients with severe hypercholesterolemia and measure its impact on real-world statin prescriptions. We identified patients with at least 1 LDL-C ≥190 mg100 ml who had a CAC scoring in the Community Benefit of No-Charge Calcium Score Screening Program (CLARIFY) study (NCT04075162) between 2014 and 2020. We explored the CAC distribution, factors associated with CAC >0, and ASCVD risk (myocardial infarction, stroke, revascularization, death). A total of 1,904 patients (1.257 women, aged 57.8 ± 9.3 years) with severe hypercholesterolemia were included. LDL-C ranged from 190 to 524 mg100 ml (mean 215.5 ± 27 mg100 ml). A total of 864 patients (45.4%) had CAC = 0 and 1,561 (82%) had CAC <100. In patients with LDL-C ≥250 mg100 ml, 67 (36.6%) had CAC = 0. Age, male gender, smoking, diabetes, systolic blood pressure, and obesity (ps ≤0.001) were associated with CAC >0. In patients with LDL-C ≥190 mg100 ml, CAC was associated with a higher risk for ASCVD events (CAC ≥100 vs CAC <100, hazard ratio 3.57 [1.81 to 7.04], p <0.001). A higher CAC category was associated with increased statin use after CAC scoring (p <0.001). In patients with severe hypercholesterolemia, 45% had CAC = 0, which was associated with a significantly lower ASCVD risk. CAC was associated with statin prescription and cholesterol lowering. In conclusion, CAC scoring may be used to clarify ASCVD risk in this heterogeneous population with severe hypercholesterolemia.

Maternal Inheritance of Familial Hypercholesterolemia Gene Mutation Predisposes to Coronary Atherosclerosis as Assessed by Calcium Score in Adulthood

BACKGROUND

Animal studies have demonstrated that fetal exposure to high maternal cholesterol levels during pregnancy predisposes to aortic atheroma in the offspring. In humans, little is known about the consequences of this exposure on the development of atherosclerotic cardiovascular disease later in life. We wanted to assess whether maternal/paternal inheritance of familial hypercholesterolemia (FH) gene mutation could be associated with subclinical coronary atherosclerosis.

METHODS

We retrospectively included 1350 patients, followed in the French registry of FH, with a documented genetic diagnosis. We selected 556 age- and sex-matched pair of patients based on the sex of the parents who transmitted the FH gene mutation, free of coronary cardiovascular event, and with a subclinical coronary atherosclerosis evaluation assessed using coronary artery calcium (CAC) score. We performed univariate and multivariate analysis to assess the individual effect of parental inheritance of the FH gene mutation on the CAC score.

RESULTS

In the whole population, patients with maternal inheritance of FH gene mutation (n=639) less frequently had a family history of premature cardiovascular events (27.7% versus 45%, P<0.0001) and were 2 years older (46.9±16.8 versus 44.7±15.9 years old, P=0.02) than those with paternal inheritance (n=711). There was no difference in the prevalence of cardiovascular events between the two groups. In the matched subgroup, maternal inheritance was significantly associated with an increase in CAC score value by 86% (95% CI, 23%-170%; P=0.003), a 1.81-fold risk of having a CAC score ≥100 Agatston units (95% CI, 1.06-3.11; P=0.03), and a 2.72-fold risk of having a CAC score ≥400 Agatston units (95% CI, 1.39-5.51; P=0.004) when compared with paternal inheritance in multivariate analysis.

CONCLUSIONS

Maternal inheritance of FH gene mutation was associated with more severe subclinical coronary atherosclerosis assessed by CAC score and may be considered as a potential cardiovascular risk factor.

Subclinical atherosclerosis determined by coronary artery calcium deposition in patients with clinical familial hypercholesterolemia

Background and aims

Limited knowledge exists regarding the association between coronary artery calcium (CAC) deposition in patients with clinical familial hypercholesterolemia (FH) and FH subtypes such as polygenic causes. We studied CAC score in patients with clinical FH and subtypes including polygenic causes of FH compared to healthy controls.

Methods

In a case-control study, we identified potential clinical FH cases registered with an LDL-C >6.7 mmol/l within a nationwide clinical laboratory database on the Faroe Islands and invited them for diagnostic evaluation according to clinical FH scoring systems. Controls were identified in the background population. All subjects were aged 18-75 years and without a history of cardiovascular disease. FH mutation testing and genotypes of twelve LDL-C associated single nucleotide polymorphisms were determined using conventional methods in selected individuals. CAC scores were assessed by cardiac CT. Odds ratios obtained using multivariate logistic regression were used as measures of association.

Results

A total of 120 clinical FH patients and 117 age- and sex-matched controls were recruited. We found a very low frequency of monogenic FH (3%), but a high level of polygenic FH (60%) in those genetically tested (54%). There was a statistically significant association between the CAC score and a diagnosis of clinical FH with the highest observed odds ratio of 5.59 (95% CI 1.65; 18.94, p = 0.006) in those with a CAC score ≥300 compared to those with a CAC of zero. In supplemental analyses, there was a strong association between CAC scores and clinical FH of a polygenic cause.

Conclusion

We found a statistically significant association between CAC levels and clinical FH with the highest observed risk estimates among clinical FH cases of a presumed polygenic cause.

New Trends and Therapies for Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is associated with an elevated risk of atherosclerosis. The finding of monogenic defects indicates higher atherosclerotic risk in comparison with hypercholesterolemia of other etiologies. However, in heterozygous FH, cardiovascular risk is heterogeneous and depends not only on high cholesterol levels but also on the presence of other biomarkers and genes. The development of atherosclerosis risk scores specific for heterozygous FH and the use of subclinical coronary atherosclerosis imaging help with identifying higher-risk individuals who may benefit from further cholesterol lowering with PCSK9 inhibitors. There is no question about the extreme high risk in homozygous FH, and intensive LDL-cholesterol-lowering therapy must be started as soon as possible. These patients have gained life free of events in comparison with the past, but a high atherosclerosis residual risk persists. Furthermore, there is also the issue of aortic and supra-aortic valve disease development. Newer therapies such as inhibitors of microsomal transfer protein and angiopoietin-like protein 3 have opened the possibility of LDL-cholesterol normalization in homozygous FH and may provide an alternative to lipoprotein apheresis for these patients. Gene-based therapies may provide more definite solutions for lowering high LDL cholesterol and consequent atherosclerosis risk for people with FH.

Coronary Artery Calcium Score to Refine the Use of PCSK9i in Asymptomatic Individuals: A Multicohort Study

Background

The value of coronary artery calcium (CAC) in the allocation of PCSK9i (proprotein convertase subtilisin/kexin type 9 inhibitors) among individuals without clinically evident atherosclerotic cardiovascular disease (ASCVD) is unknown for indications that do not require confirmed familial hypercholesterolemia. We aimed to assess the ability of CAC to stratify ASCVD risk under 3 non–familial hypercholesterolemia PCSK9i allocation paradigms.

Methods and Results

We included participants without clinically evident ASCVD from MESA (Multi‐Ethnic Study of Atherosclerosis), CARDIA (Coronary Artery Risk Development in Young Adults) study, DHS (Dallas Heart Study), and HNR (Heinz Nixdorf Recall) study. Three PCSK9i eligibility scenarios were defined: a broad scenario informed only by high low‐density lipoprotein cholesterol levels (N=567), a restrictive one combining higher low‐density lipoprotein cholesterol levels and presence of ≥2 additional risk factors (N=127), and a high‐risk scenario where individuals with subclinical organ damage or high estimated risk would be treated to achieve low‐density lipoprotein cholesterol <55 mg/dL (N=471). The high‐risk scenario had the highest ASCVD event rates (27.8% at 10 years). CAC=0 was observed in 35% participants in the broad scenario, 25% in the restrictive scenario, and 16% in the high‐risk scenario. In all, CAC=0 was associated with the lowest incident ASCVD rates at 5 and 10 years, and CAC burden was independently associated with ASCVD events adjusting for traditional risk factors.

Conclusions

CAC may be used to refine the allocation of PCSK9i, potentially leading to a more conservative use if CAC=0. The value of CAC testing is greater in scenarios that use low‐density lipoprotein cholesterol levels and/or traditional risk factors to define PCSK9i eligibility (CAC=0 present in 1 of 3–4 patients), whereas its prevalence is lower when allocation is informed by presence of noncoronary subclinical organ damage.

Visual Coronary and Aortic Calcium Scoring on Chest Computed Tomography Predict Mortality in Patients With Low-Density Lipoprotein-Cholesterol ≥190 mg/dL

BACKGROUND

Current guidelines recommend coronary artery calcium (CAC) scoring for stratification of atherosclerotic cardiovascular disease risk only in patients with borderline to intermediate risk score by the pooled cohort equation with low-density lipoprotein-cholesterol (LDL-C) of 70 to 190 mg/dL. It remains unknown if CAC or thoracic aorta calcification (TAC), detected on routine chest computed tomography, can provide further risk stratification in patients with LDL-C≥190 mg/dL.

METHODS

From a multisite medical center, we retrospectively identified all patients from March 2005 to June 2021 age ≥40 years, without established atherosclerotic cardiovascular disease and LDL-C≥190 mg/dL who had non-gated non-contrast chest computed tomography within 3 years of LDL-C measurement. Ordinal CAC and TAC scores were measured by visual inspection. Kaplan-Meier curves and multivariable Cox-regression models were built to ascertain the association of CAC and TAC scores with all-cause mortality.

RESULTS

We included 811 patients with median age 59 (53-68) years, 262 (32.3%) were male, and LDL-C median level was 203 (194-217) mg/dL. Patients were followed for 6.2 (3.29-9.81) years, and 109 (13.4%) died. Overall, 376 (46.4%) of patients had CAC=0 and 226 (27.9%) had TAC=0. All-cause mortality increased with any CAC and moderate to severe TAC. In a multivariate model, patients with CAC had a significantly higher mortality compared with those without CAC: mild hazard ratio (HR), 1.71 (1.03-2.83), moderate HR, 2.12 (1.14-3.94), and severe HR, 3.49 (1.94-6.27). Patients with moderate TAC (HR, 2.34 [1.19-4.59]) and those with severe TAC (HR, 3.02 [1.36-6.74]) had higher mortality than those without TAC.

CONCLUSIONS

In patients without history of atherosclerotic cardiovascular disease and LDL-C≥190 mg/dL, the presence and severity of CAC and TAC are independently associated with all-cause mortality.

Updates on the Use of Subclinical Atherosclerosis to Predict Risk of Cardiovascular Events in Heterozygous Familial Hypercholesterolemia

PURPOSE OF REVIEW

The high variability of cardiovascular risk in heterozygous familial hypercholesterolemia (HeFH) is a challenge for therapeutical management. Subclinical cardiovascular imaging represents a tool to overcome this challenge. The purpose of this review is to update the reader on the most recent findings on the non-invasive detection of atherosclerotic burden by carotid doppler ultrasound (US), coronary artery calcium (CAC) score, and computed tomography coronary angiography (CTCA) for the optimization of risk stratification in HeFH subjects.

RECENT FINDINGS

Carotid ultrasound (US) proved its efficacy in the long-term follow-up of HeFH children treated early on with statins, showing a significant reduction of atherosclerotic progression compared to untreated unaffected siblings. The added value of CAC score has been confirmed to predict the risk of cardiovascular events and improve risk stratification provided by available risk equations in asymptomatic HeFH subjects from large prospective cross-national cohorts. Additionally, CTCA provides detailed information on plaque quality and stability, but its role in primary prevention HeFH subjects needs to be further explored. Cardiovascular imaging for the detection of subclinical atherosclerotic cardiovascular disease in HeFH is a promising tool to improve diagnostic and therapeutical management of this undertreated and late-diagnosed disease.

Coronary Artery Calcium for Risk Assessment in Young Adults

PURPOSE OF REVIEW

To review the prognostic significance and clinical utility of coronary artery calcium (CAC) for risk assessment for atherosclerotic cardiovascular disease (ASCVD) in younger adults.

RECENT FINDINGS

Data from over 3000 young adults (mean age of 40.3 ± 3.6 followed for 12.5 years) in the CARDIA registry found that in an asymptomatic, community representative sample, there was a low prevalence of CAC (~ 10%) but those with CAC had an exponential increase in CAC over time and significantly higher rates of ASCVD events. Alternatively, data from the CAC consortium analyzed 22,346 asymptomatic individuals undergoing CAC for clinical indications (mean age 43.5 ± 4.5 years, followed for 13 ± 4 years) and found a much higher prevalence of CAC at 34% with rates of coronary heart disease mortality that varied significantly according to CAC. In younger adults, CAC provides clear prognostic value and can be considered in select individuals with uncertainties about their ASCVD risk or the benefit of preventive therapies.

Genetic Lipid Disorders Associated with Atherosclerotic Cardiovascular Disease: Molecular Basis to Clinical Diagnosis and Epidemiologic Burden

Genetic lipid disorders, ranging from common dyslipidemias such as familial hypercholesterolemia, lipoprotein (a), and familial combined hyperlipidemia to rare disorders including familial chylomicronemia syndrome and inherited hypoalphalipoproteinemias (ie, Tangier and fish eye diseases), affect millions of individuals in the United States and tens of millions around the world and are often undiagnosed in the general population. Clinicians should take into consideration the potential of inherited lipid disorders or syndromes when severe derangements in lipid parameters are observed. Patients' combined genotype and phenotype should be evaluated in conjunction with a host of environmental factors impacting their risk of atherosclerotic cardiovascular disease.

Association of Coronary Plaque With Low-Density Lipoprotein Cholesterol Levels and Rates of Cardiovascular Disease Events Among Symptomatic Adults

IMPORTANCE

Atherosclerosis burden and coronary artery calcium (CAC) are associated with the risk for atherosclerotic cardiovascular disease (ASCVD) events, with absence of plaque and CAC indicating low risk. Whether this is true in patients with elevated levels of low-density lipoprotein cholesterol (LDL-C) is not known. Specifically, a high prevalence of noncalcified plaque might signal high risk.

OBJECTIVE

To determine the prevalence of noncalcified and calcified plaque in symptomatic adults and assess its association with cardiovascular events across the LDL-C spectrum.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included symptomatic patients undergoing coronary computed tomographic angiography from January 1, 2008, to December 31, 2017, from the seminational Western Denmark Heart Registry. Follow-up was completed on July 6, 2018. Data were analyzed from April 2 to December 2, 2021.

EXPOSURES

Prevalence of calcified and noncalcified plaque according to LDL-C strata of less than 77, 77 to 112, 113 to 154, 155 to 189, and at least 190 mg/dL. Severity of coronary artery disease was categorized using CAC scores of 0, 1 to 99, and ≥100, where higher numbers indicate greater CAC burden.

MAIN OUTCOMES AND MEASURES

Atherosclerotic cardiovascular disease events (myocardial infarction and stroke) and death.

RESULTS

A total of 23 143 patients with a median age of 58 (IQR, 50-65) years (12 857 [55.6%] women) were included in the analysis. During median follow-up of 4.2 (IQR, 2.3-6.1) years, 1029 ASCVD and death events occurred. Across all LDL-C strata, absence of CAC was a prevalent finding (ranging from 438 of 948 [46.2%] in patients with LDL-C levels of at least 190 mg/dL to 4370 of 7964 [54.9%] in patients with LDL-C levels of 77-112 mg/dL) and associated with no detectable plaque in most patients, ranging from 338 of 438 (77.2%) in those with LDL-C levels of at least 190 mg/dL to 1067 of 1204 (88.6%) in those with LDL-C levels of less than 77 mg/dL. In all LDL-C groups, absence of CAC was associated with low rates of ASCVD and death (6.3 [95% CI, 5.6-7.0] per 1000 person-years), with increasing rates in patients with CAC scores of 1 to 99 (11.1 [95% CI, 10.0-12.5] per 1000 person-years) and CAC scores of at least 100 (21.9 [95% CI, 19.9-24.4] per 1000 person-years). Among those with CAC scores of 0, the event rate per 1000 person-years was 6.3 (95% CI, 5.6-7.0) in the overall population compared with 6.9 (95% CI, 4.0-11.9) in those with LDL-C levels of at least 190 mg/dL. Across all LDL-C strata, rates were similar and low in those with CAC scores of 0, regardless of whether they had no plaque or purely noncalcified plaque.

CONCLUSIONS AND RELEVANCE

The findings of this cohort study suggest that in symptomatic patients with severely elevated LDL-C levels of at least 190 mg/dL who are universally considered to be at high risk by guidelines, absence of calcified and noncalcified plaque on coronary computed tomographic angiography was associated with low risk for ASCVD events. These results further suggest that atherosclerosis burden, including CAC, can be used to individualize treatment intensity in patients with severely elevated LDL-C levels.

Past, Present, and Future of Familial Hypercholesterolemia Management

Familial hypercholesterolemia (FH) is a monogenic form of severe hypercholesterolemia that, if left untreated, is associated with early onset of atherosclerosis. FH derives from genetic variants that lead to inefficient hepatic clearance of low-density lipoprotein (LDL) particles from the circulation. The FH phenotype is encountered in approximately 1 of every 300 people. The risk of atherosclerotic cardiovascular disease (ASCVD) is higher in those with FH than in normolipidemic individuals and in those with polygenic hypercholesterolemia. FH is usually diagnosed by clinical scores that consider hypercholesterolemia, family history of early ASCVD and hypercholesterolemia, and cutaneous stigmata. Genetic diagnosis is important and should be offered to individuals suspected of FH. Family cascade screening is important to identify asymptomatic hypercholesterolemic individuals. Despite the high risk of ASCVD, this risk is heterogenous in heterozygous FH and depends not only on high LDL cholesterol (LDL-C) but also on other risk biomarkers. Risk can be evaluated by considering biomarkers such as male sex, late-onset therapy (> age 40), LDL-C > 310 mg/dL, low high-density lipoprotein cholesterol, elevated lipoprotein(a), obesity, diabetes, and hypertension by using specific risk equations and by detecting subclinical coronary atherosclerosis. Statins are the main therapy for FH and change the natural history of ASCVD; however, most individuals persist with elevated LDL-C. PCSK9 inhibitors provide robust and safe LDL-C lowering in FH, although elevated costs preclude their widespread use. Newer therapies such as ANGPTL3 inhibitors add intensive LDL-C lowering for refractory forms of FH. Finally, while it is possible to normalize LDL-C in people with FH, the disease unfortunately is still severely underdiagnosed and undertreated.

The Added Value of Coronary Calcium Score in Predicting Cardiovascular Events in Familial Hypercholesterolemia

OBJECTIVES

This study aimed at investigating the additional contribution of coronary artery calcium (CAC) score to SAFEHEART (Spanish Familial Hypercholesterolemia Cohort Study) risk equation (SAFEHEART-RE) for cardiovascular risk prediction in heterozygous familial hypercholesterolemia (HeFH).

BACKGROUND

Common cardiovascular risk equations are imprecise for HeFH. Because of the high phenotype variability of HeFH, CAC score could help to better stratify the risk of atherosclerotic cardiovascular disease (ASCVD).

METHODS

REFERCHOL (French Registry of Familial Hypercholesterolemia) and SAFEHEART are 2 ongoing national registries on HeFH. We analyzed data from primary prevention HeFH patients undergoing CAC quantification. We used probability-weighted Cox proportional hazards models to estimate HRs. Area under the receiver-operating characteristic curve (AUC) and net reclassification improvement (NRI) were used to compare the incremental contribution of CAC score when added to the SAFEHEART-RE for ASCVD prediction. ASCVD was defined as coronary heart disease, stroke or transient ischemic attack, peripheral artery disease, resuscitated sudden death, and cardiovascular death.

RESULTS

We included 1,624 patients (mean age: 48.5 ± 12.8 years; men: 45.7%) from both registries. After a median follow-up of 2.7 years (interquartile range: 0.4-5.0), ASCVD occurred in 81 subjects. The presence of a CAC score of >100 was associated with an HR of 32.05 (95% CI: 10.08-101.94) of developing ASCVD as compared to a CAC score of 0. Receiving-operating curve analysis showed a good performance of CAC score alone in ASCVD prediction (AUC: 0.860 [95% CI: 0.853-0.869]). The addition of log(CAC + 1) to SAFEHEART-RE resulted in a significantly improved prediction of ASCVD (AUC: 0.884 [95% CI: 0.871-0.894] for SAFEHEART-RE + log(CAC + 1) vs AUC: 0.793 [95% CI: 0.779-0.818] for SAFEHEART-RE; P < 0.001). These results were confirmed also when considering only hard cardiovascular endpoints. The addition of CAC score was associated with an estimated overall net reclassification improvement of 45.4%.

CONCLUSIONS

CAC score proved its use in improving cardiovascular risk stratification and ASCVD prediction in statin-treated HeFH.

Role of coronary artery calcium score in the primary prevention of cardiovascular disease

First developed in 1990, the Agatston coronary artery calcium (CAC) score is an international guideline-endorsed decision aid for further risk assessment and personalized management in the primary prevention of atherosclerotic cardiovascular disease. This review discusses key international studies that have informed this 30 year journey, from an initial coronary plaque screening paradigm to its current role informing personalized shared decision making. Special attention is paid to the prognostic value of a CAC score of zero (the so called "power of zero"), which, in a context of low estimated risk thresholds for the consideration of preventive therapy with statins in current guidelines, may be used to de-risk individuals and thereby inform the safe delay or avoidance of certain preventive therapies. We also evaluate current recommendations for CAC scoring in clinical practice guidelines around the world, and past and prevailing barriers for its use in routine patient care. Finally, we discuss emerging approaches in this field, with a focus on the potential role of CAC informing not only the personalized allocation of statins and aspirin in the general population, but also of other risk-reduction therapies in special populations, such as individuals with diabetes and people with severe hypercholesterolemia.

Coronary lesion complexity in patients with heterozygous familial hypercholesterolemia hospitalized for acute myocardial infarction: data from the RICO survey

BACKGROUND

Although patients with familial heterozygous hypercholesterolemia (FH) have a high risk of early myocardial infarction (MI), the coronary artery disease (CAD) burden in FH patients with acute MI remains to be investigated.

METHODS

The data for all consecutive patients hospitalized in 2012-2019 for an acute MI and who underwent coronary angiography were collected from a multicenter database (RICO database). FH (n = 120) was diagnosed using Dutch Lipid Clinic Network criteria (score ≥ 6). We compared the angiographic features of MI patients with and without FH (score 0-2) (n = 234) after matching for age, sex, and diabetes (1:2).

RESULTS

Although LDL-cholesterol was high (208 [174-239] mg/dl), less than half of FH patients had chronic statin treatment. When compared with non-FH patients, FH increased the extent of CAD (as assessed by SYNTAX score; P = 0.005), and was associated with more frequent multivessel disease (P = 0.004), multiple complex lesions (P = 0.022) and significant stenosis location on left circumflex and right coronary arteries. Moreover, FH patients had more multiple lesions, with an increased rate of bifurcation lesions or calcifications (P = 0.021 and P = 0.036, respectively). In multivariate analysis, LDL-cholesterol levels (OR 1.948; 95% CI 1.090-3.480, P = 0.024) remained an independent estimator of anatomical complexity of coronary lesions, in addition to age (OR 1.035; 95% CI 1.014-1.057, P = 0.001).

CONCLUSIONS

FH patients with acute MI had more severe CAD, characterized by complex anatomical features that are mainly dependent on the LDL-cholesterol burden. Our findings reinforce the need for more aggressive preventive strategies in these high-risk patients, and for intensive lipid-lowering therapy as secondary prevention.

Evaluation of Transthoracic Echocardiography in the Assessment of Atherosclerosis of the Left Main Coronary Artery: Comparison with Optical Frequency Domain Imaging (a Pilot Study)

Background: Risk stratification using non-invasive imaging of the coronary vessels is emerging as an optimal standard of care for patients with dyslipidemias. Of particular interest is the evaluation of the left main coronary artery (LMCA), where calcium deposition appears to be a predictor of cardiovascular events. Methods: In coronary patients, we evaluated wall thickness and internal diameter of the LMCA examined by transthoracic echocardiography (TTE) and compared these with findings obtained by optical frequency domain imaging (OFDI), this latter also used to evaluate calcium deposition. Results: A significant positive correlation between TTE and OFDI for the anterior wall thickness (r = 0.41, p = 0.043) and internal diameter (r = 0.36, p = 0.048) of the LMCA was detected. Echocardiographic wall measurements were higher in patients with fibro-calcific plaques. The receiver operating characteristic (ROC) curve showed that an anterior wall thickness of LMCA ≥ 1.4 mm was predictive of fibro-calcific plaque (area under the curve = 0.815 and p = 0.006), sensitivity and specificity being 76.9% and 80%, respectively (Youden’s Index = 0.56). Conclusions: Measurement of anterior wall thickness of the LMCA by TTE and OFDI appears to be closely correlated and may predict the presence of coronary calcification.

Correlates of Coronary Artery Calcification Prevalence and Severity in Patients With Heterozygous Familial Hypercholesterolemia

Background

Determinants of coronary artery calcification (CAC) prevalence and severity in heterozygous familial hypercholesterolemia (HeFH) remain understudied. The objective of this cross-sectional study was to investigate correlates of CAC in patients with HeFH.

Methods

A CAC score was calculated by a noncontrast computed tomography scan in women (n = 68) and men (n = 78) with genetically defined HeFH. We classified CAC prevalence and severity using 3 categories: CAC score = 0 Agatston Unit (AU), CAC score = 1-100 AU, and CAC score > 100 AU. Information on potential correlates of CAC including familial and personal health history, cardiovascular risk factors, lipid-lowering medication, and lifestyle habits was collected.

Results

A total of 95 patients had prevalent CAC. Independent correlates of CAC prevalence and severity included age (odds ratio [OR] per 10 years: 5.06, 95% confidence interval [CI]: 3.19, 7.93, P < 0.0001), family history of premature cardiovascular disease (OR: 3.88, 95% CI: 1.71, 8.81, P = 0.001), male sex (OR: 3.40, 95% CI: 1.49, 7.78, P = 0.004), statin use (OR: 15.5, 95% CI: 1.89, 126, P = 0.01), diet quality assessed with the Alternative Healthy Eating Index score (OR per 1 standard deviation: 0.59, 95% CI: 0.39, 0.90, P = 0.01), ever smoking (OR: 3.06, 95% CI: 1.20, 7.81, P = 0.02), receptor-negative genotype (OR: 3.17, 95% CI: 1.16, 8.66, P = 0.02), lipoprotein(a) year-score (OR per 1 standard deviation of log-transformed year-score: 1.53, 95% CI: 0.99, 2.36, P = 0.05).

Conclusions

In individuals with HeFH, age, family history of premature cardiovascular disease, sex, statin use, diet quality, smoking status, the LDLR genotype, and lipoprotein(a) concentrations were independently associated with CAC prevalence and severity.

Polygenic Contribution to Low-Density Lipoprotein Cholesterol Levels and Cardiovascular Risk in Monogenic Familial Hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH) is a common autosomal codominant genetic disorder, which causes elevated levels of low-density lipoprotein cholesterol (LDL-C) and increased risk of premature atherosclerotic cardiovascular disease (ASCVD). Even among individuals with monogenic FH, there is substantial interindividual variability in LDL-C levels and risk of ASCVD. We assessed the influence of an LDL-C polygenic score on levels of LDL-C and risk of ASCVD for individuals with monogenic FH.

METHODS

We constructed a weighted LDL-C polygenic score, composed of 28 single-nucleotide variants, for individuals with monogenic FH from the British Columbia FH (n=262); Nutrition, Metabolism and Atherosclerosis Clinic (n=552); and UK Biobank cohorts (n=306). We assessed the association between LDL-C polygenic score with LDL-C levels and ASCVD risk using linear regression and Cox-proportional hazard models, respectively. ASCVD was defined as myocardial infarction, coronary or carotid revascularization, transient ischemic attack, or stroke. The results from individual cohorts were combined in fixed-effect meta-analyses.

RESULTS

Levels of LDL-C were significantly associated with LDL-C polygenic score in the Nutrition, Metabolism and Atherosclerosis Clinic cohort, UK Biobank cohort, and in the meta-analysis (β [95% CI]=0.13 [0.072-0.19] per a 20% increase in LDL-C polygenic score percentile, P<0.0001). Additionally, an elevated LDL-C polygenic score (≥80th percentile) was associated with a trend towards increased ASCVD risk in all 3 cohorts individually. This association was statistically significant in the meta-analysis (hazard ratio [95% CI]=1.48 [1.02-2.14], P=0.04).

CONCLUSIONS

Polygenic contributions to LDL-C explain some of the heterogeneity in clinical presentation and ASCVD risk for individuals with FH.

Association of Monogenic vs Polygenic Hypercholesterolemia With Risk of Atherosclerotic Cardiovascular Disease

Importance

Monogenic familial hypercholesterolemia (FH) is associated with lifelong elevations in low-density lipoprotein cholesterol (LDL-C) levels and increased risk of atherosclerotic cardiovascular disease (CVD). However, many individuals with hypercholesterolemia have a polygenic rather than a monogenic cause for their condition. It is unclear if a genetic variant for hypercholesterolemia alters the risk of CVD.

Objectives

To assess whether a genetic variant for hypercholesterolemia alters the risk of atherosclerotic CVD and to evaluate how this risk compares with that of nongenetic hypercholesterolemia.

Design, Setting, and Participants

In this genetic-association, case-control, cohort study, individuals aged 40 to 69 years were recruited by the UK Biobank from across the United Kingdom between March 13, 2006, and October 1, 2010, and followed up until March 31, 2017. Genotyping array and exome sequencing data from the UK Biobank cohort were used to identify individuals with monogenic (LDLR, APOB, and PCSK9) or polygenic hypercholesterolemia (LDL-C polygenic score >95th percentile based on 223 single-nucleotide variants in the entire cohort). The data were analyzed from July 1, 2019, to December 30, 2019.

Main Outcomes and Measures

The study investigated the association of genotype with the risk of coronary and carotid revascularization, myocardial infarction, ischemic stroke, and all-cause mortality among the overall study population and among participants with monogenic FH (n = 277), polygenic hypercholesterolemia (n = 2379), or hypercholesterolemia with undetermined cause (n = 2232) at comparable levels of LDL-C measured at study enrollment.

Results

For the 48 741 individuals with genotyping array and exome sequencing data, the mean (SD) age was 56.6 (8.0) years, and 54.5% were female (n = 26 541 of 48 741). A monogenic FH variant for hypercholesterolemia was found in 277 individuals (0.57%, 1 in 176 individuals). Participants with monogenic FH were significantly more likely than those without monogenic FH to experience an atherosclerotic CVD event at 55 years or younger (17 of 277 [6.1%] vs 988 of 48 464 [2.0%]; P < .001). Compared with the general population, both monogenic and polygenic hypercholesterolemia were associated with an increased risk of CVD events. Moreover, among individuals with comparable levels of LDL-C, both monogenic (hazard ratio, 1.93; 95% CI, 1.34-2.77; P < .001) and polygenic hypercholesterolemia (hazard ratio, 1.26; 95% CI, 1.03-1.55; P = .03) were significantly associated with an increased risk of CVD events compared with the risk of such events in individuals with hypercholesterolemia without an identified genetic cause.

Conclusions and Relevance

The findings of this study suggest that among individuals with hypercholesterolemia, genetic determinants of LDL-C levels may impose additional risk of CVD. Thus, understanding the possible genetic cause of hypercholesterolemia may provide important prognostic information to treat patients.