Factors Associated with Carotid Atherosclerosis and Achilles Tendon Thickness in Japanese Patients with Familial Hypercholesterolemia: A Subanalysis of the Familial Hypercholesterolemia Expert Forum (FAME) Study

Clinical Impact of Lipoprotein (a) and Cumulative Low-Density Lipoprotein Cholesterol Exposure on Coronary Artery Disease in Patients with Heterozygous Familial Hypercholesterolemia

AIMS

Elevated lipoprotein (a) (Lp[a]), predominantly determined by genetic variability, causes atherosclerotic cardiovascular disease (ASCVD), particularly in patients with familial hypercholesterolemia (FH). We aimed to elucidate the clinical impact of Lp(a) and cumulative exposure to low-density lipoprotein cholesterol (LDL-C) on CAD in patients with FH.

METHODS

One hundred forty-seven patients clinically diagnosed with heterozygous familial hypercholesterolemia (HeFH) were retrospectively investigated. Patients were divided into 2 groups according to the presence of CAD. Their clinical characteristics and lipid profiles were evaluated.

RESULTS

There were no significant differences in untreated LDL-C levels between the 2 groups (p=0.4), whereas the cumulative exposure to LDL-C and Lp(a) concentration were significantly higher in patients with CAD (11956 vs. 8824 mg-year/dL, p＜0.01; 40 vs. 14 mg/dL, p＜0.001, respectively). A receiver operating characteristic (ROC) curve analysis demonstrated that the cutoff values of Lp(a) and cumulative LDL-C exposure to predict CAD in patients with FH were 28 mg/dL (AUC 0.71) and 10600 mg-year/dL (AUC 0.77), respectively. A multivariate analysis revealed that cumulative LDL-C exposure ≥ 10600 mg-year/dL (p＜0.0001) and Lp(a) level ≥ 28 mg/dL (p＜0.001) were independent predictors of CAD. Notably, the risk of CAD remarkably increased to 85.7% with smoking, Lp(a) ≥ 28 mg/dL, and cumulative LDL-C exposure ≥ 10600 mg-year/dL (odds ratio: 46.5, 95%CI: 5.3-411.4, p＜0.001).

CONCLUSIONS

This study demonstrated an additive effect of Lp(a) and cumulative LDL-C exposure on CAD in patients with HeFH. Interaction with traditional risk factors, particularly smoking and cumulative LDL-C exposure, enormously enhances the cardiovascular risk in this population.

Risk Assessment for Cardiovascular Events using Achilles Tendon Thickness and Softness and Intima-Media Thickness in Familial Hypercholesterolemia

AIMS

This was a retrospective cohort study that aimed to determine cutoff values for major adverse cardiovascular events (MACEs) in patients with heterozygous FH (HeFH) for Achilles tendon (AT) thickness (ATT) measured by ultrasonography (US-ATT) and radiography (Xp-ATT), AT softness, and intima-media thickness of carotid artery (C-IMT), and to examine the effectiveness of these values as well as AT calcification as indexes in assessing risk for MACEs.

METHODS

The subjects were 391 clinically diagnosed HeFH patients. Kaplan-Meier curves were drawn based on the threshold values for the individual indexes calculated from ROC curves, and multivariate analysis was used to examine whether they were predictors of the development of MACEs.

RESULTS

The median observation period was 1,239 days (700-1,827 days). Twenty-one subjects (5%) had MACEs during the observation period. The cutoff values for MACEs for US-ATT were 9.9 mm in males and 7.1 mm in females, and those for C-IMT were 1.6 mm in males and 1.5 mm in females. Subjects were classified into two groups according to whether they were above or below the cutoff values and presence of calcification, and we compared MACE rates between them. MACE rates were significantly increased in groups with AT thickening determined by ultrasonography (P＜0.001), AT softening (P＜0.001), presence of calcification in AT (P=0.016) and greater C-IMT (P＜0.001). However, classification according to Xp-ATT revealed no significant difference in MACE rate (P=0.112).

CONCLUSIONS

These thresholds and examination for AT calcification will help in risk assessment for patients in Japanese FH practice and encourage stricter and more comprehensive management for patients who exceed the thresholds.

Validation of physical examinations of tendon xanthomas and changes in the cutoff values of Achilles tendon thickness on radiography in the clinical criteria of heterozygous familial hypercholesterolemia in Japan

BACKGROUND

The 2022 Japan Atherosclerosis Society familial hypercholesterolemia (FH) clinical criteria were modified. In particular, the cutoff value of Achilles tendon thickness (ATT) on radiography was changed from ≥9 mm in both sexes to ≥8.0 mm in men and ≥7.5 mm in women.

METHODS

A total of 872 patients with FH were retrospectively reviewed. Patients were categorized by an ATT of <7.5/8.0 mm (group 1), ≥7.5/8.0 and <9.0 mm (group 2, new group with FH by ATT), and ≥9 mm (group 3).

RESULTS

In total, 492 patients fell into group 1, 102 in group 2, and 263 in group 3, and 14.0%, 55.9%, and 79.8% of patients in groups 1, 2, and 3, respectively, were positive for a FH mutation. Further, among patients with low-density lipoprotein cholesterol >180 mg/dL, 37.3%, 77.3%, and 86.5% of patients had a FH mutation in groups 1, 2, and 3, respectively. The proportion of patients with protein-truncating mutation (3.8%, 16.7%, and 53.2%, respectively) differed significantly across groups 1 through 3, respectively. Interestingly, only a very small proportion of the patients in groups 2 and 3 had palpable xanthomas (3.0% and 14.4% respectively).

CONCLUSIONS

This study validates the new radiographic ATT criteria, since the vast majority of patients in the intermediate ATT category had true FH, as shown by positive genetic testing, whereas the old ATT criteria left them with just a deferred diagnosis of FH. In addition, use of physical examination alone for the presence of tendon xanthoma may lead to underdiagnosis of FH.

Factors associated with the presence of tendon xanthomas in familial hypercholesterolemia

INTRODUCTION AND OBJECTIVES

Tendon xanthomas (TX) are lipid deposits highly specific to familial hypercholesterolemia (FH). However, there is significant variability in their presentation among FH patients, primarily due to largely unknown causes. Lipoprotein(a) is a well-established independent risk factor for atherosclerotic cardiovascular disease in the general population as well as in FH. Given the wide variability of lipoprotein(a) among FH individuals and the likelihood that TX may result from a proatherogenic and proinflammatory condition, the objective of this study was to analyze the size of TX in the Achilles tendons of FH participants and the variables associated with their presence, including lipoprotein(a) concentration.

METHODS

A cross-sectional study was conducted on 377 participants with a molecular diagnosis of heterozygous FH. Achilles tendon maximum thickness (ATMT) was measured using ultrasonography with standardized equipment and procedures. Demographic variables and lipid profiles were collected. A multivariate linear regression model using a log-Gaussian approach was used to predict TX size. Classical cardiovascular risk factors and lipoprotein(a) were included as explanatory variables.

RESULTS

The mean low-density lipoprotein cholesterol level was 277mg/dL without lipid-lowering treatment, and the median ATMT was 5.50mm. We demonstrated that age, sex, low-density lipoprotein cholesterol, and lipoprotein(a) were independently associated with ATMT. However, these 4 variables did not account for most the interindividual variability observed (R2=0.205).

CONCLUSIONS

TX, a characteristic hallmark of FH, exhibit heterogeneity in their presentation. Interindividual variability can partially be explained by age, male sex, low-density lipoprotein cholesterol, and lipoprotein(a) but these factors account for only 20% of this heterogeneity.

Treatment of pediatric heterozygous familial hypercholesterolemia 7 years after the EAS recommendations: Real-world results from a large French cohort

BACKGROUND

Heterozygous familial hypercholesterolemia (HeFH) predisposes to premature cardiovascular diseases. Since 2015, the European Atherosclerosis Society has advocated initiation of statins at 8-10 years of age and a low-density lipoprotein cholesterol (LDL-C) target of <135 mg/dL. Longitudinal data from large databases on pharmacological management of pediatric HeFH are lacking.

OBJECTIVE

Here, we describe treatment patterns and LDL-C goal attainment in pediatric HeFH using longitudinal real-world data.

METHODS

This was a retrospective and prospective multicenter cohort study (2015-2021) of children with HeFH, diagnosed genetically or clinically, aged <18 years, and followed up in the National French Registry of FH (REFERCHOL). Data on the study population as well as treatment patterns and outcomes are summarized as mean±SD.

RESULTS

We analyzed the data of 674 HeFH children (age at last visit: 13.1 ± 3.6 years; 82.0 % ≥10 years; 52.5 % females) who were followed up for a mean of 2.8 ± 3.5 years. Initiation of lipid-lowering therapy was on average at 11.8 ± 3.0 years of age for a duration of 2.5 ± 2.8 years. At the last visit, among patients eligible for treatment (573), 36 % were not treated, 57.1 % received statins alone, 6.4 % statins with ezetimibe, and 0.2 % ezetimibe alone. LDL-C was 266±51 mg/dL before treatment and 147±54 mg/dL at the last visit (-44.7 %) in treated patients. Regarding statins, 3.3 %, 65.1 %, and 31.6 % of patients received high-, moderate-, and low-intensity statins, respectively. Overall, 59 % of children on statin therapy alone and 35.1 % on bitherapy did not achieve the LDL-C goal; fewer patients in the older age group did not reach the treatment goal.

CONCLUSION

Pediatric patients with FH followed up in specialist lipid clinics in France receive late treatment, undertreatment, or suboptimal treatment and half of them do not reach the therapeutic LDL-C goal. Finding a more efficient framework for linking scientific evidence to clinical practice is needed.

Early Atherosclerosis in Familial Hypercholesterolemia Patients: Significance of Vascular Markers for Risk Stratification

BACKGROUND

Familial hypercholesterolemia (FH) is a genetic disorder that manifests as impaired low-density lipoprotein cholesterol (LDL-C) metabolism, resulting in lifelong exposure to high cholesterol levels and increased risk of cardiovascular disease (CVD). There is heterogeneity in cardiovascular risk for FH patients, so risk stratification is of utmost importance. The aim of this study was to evaluate the impact of increases in LDL-C and the impact of other CVD risk factors on vascular markers in the FH patient population.

METHODS

A total of 428 patients were included in this study and divided into two groups according to age: ≤40 years in the first group and ≥41 years in the second group. Vascular markers of atherosclerosis included the common carotid artery (CCA) intima-media thickness (IMT), pulse wave velocity (PWV), flow-mediated dilation (FMD), ankle-brachial index (ABI), and cardio-vascular index (CAVI). The influence of traditional CVD risk factors on atherosclerotic changes in vascular markers was analyzed.

RESULTS

A statistically significant difference in IMT was detected between the same sex and different age groups (p < 0.001), whereas no significant difference was detected between the sexes within each age group. In the ≤40-year-old group, the mean IMT among males was 612.5 μm (±88.2) and that among females was 580.6 μm (±77.7) (p > 0.05); in the ≥41-year-old group, the mean IMT was 697.4 μm (±138.4) for males and 700.3 μm (±114.4) for females (p > 0.05). Higher LDL-C was associated with greater IMT (r = 0.405; p = 0.009) in the younger age group (≤40 years); however, in the older age group (≥41 years), this correlation was not evident (r = -0.07; p = 0.596). Carotid plaque formation was more common among males (OR = 2.2; 95% CI: 1.2-4.0) and hypertensive patients (OR = 2.7; 95% CI: 1.6-4.7). Age was a mildly significant risk factor for increased ABI (β = 0.13, p < 0.05). FMD was found to be impaired for all patients, and no risk factors were shown to have further influence. Age was a significant risk factor for increased arterial stiffness, as measured by both the CAVI and PWV.

CONCLUSIONS

Although vascular markers of atherosclerosis may provide a unique and valuable way to evaluate cardiovascular risk, the results of this study show that only increased IM thickness could be beneficial for risk stratification in young FH patients, whereas other vascular markers of atherosclerosis would be excessive, as they do not provide merit in risk evaluation in this population.

Prognostic impact of Achilles tendon thickness in elderly patients after percutaneous coronary intervention: A 5-year follow-up

BACKGROUND

Evaluating the Achilles tendon thickness (ATT) may be beneficial for risk stratification of long-term secondary cardiovascular events among patients who underwent percutaneous coronary intervention (PCI).

METHODS

This observational study evaluated major adverse cardiac and cerebrovascular events (MACCEs), including cardiovascular death/death from unknown causes, at 5 years after PCI according to the baseline ATT (≥9 mm vs. <9 mm).

RESULTS

Overall, 355 patients aged ≥75 years were enrolled; 47 (13.2 %) and 308 patients (86.8 %) had an ATT ≥9 mm and <9 mm, respectively. The incidence of MACCEs at 5 years was numerically higher but not significantly different for the ATT ≥9 mm group compared with the ATT <9 mm group (Gray's p-value = 0.10). However, the incidence of cardiovascular death/death from unknown causes at 5 years was significantly higher in the ATT ≥9 mm group than in the ATT <9 mm group (Gray's p-value = 0.034). Multivariable Fine and Gray competing risk analysis showed that an ATT ≥9 mm was associated with both MACCEs [hazard ratio (HR), 1.95; 95 % confidence interval (CI), 1.12-3.41; p-value = 0.019] and cardiovascular death/death from unknown causes (HR, 2.81; 95 % CI, 1.31-6.03; p-value = 0.008) at 5 years in patients with an estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m2.

CONCLUSIONS

A significantly thick Achilles tendon could be a marker for MACCEs, including cardiovascular death/death from unknown causes, at 5 years among elderly patients with an eGFR ≥30 mL/min/1.73 m2 after PCI.

Gaps in the Care of Subjects with Familial Hypercholesterolemia: Insights from the Thai Familial Hypercholesterolemia Registry

AIMS

Familial hypercholesterolemia (FH) is currently underdiagnosed and undertreated. The establishment of a FH registry could facilitate a deeper understanding of this disease. We described the clinical characteristics of subjects with FH from the Thai FH Registry, compared our data with the regional and global data, and identified gaps in the care of these subjects.

METHODS

A multicenter, nationwide prospective FH registry was established in Thailand. Our data were compared with those of the European Atherosclerosis Society-FH Studies Collaboration. Multiple logistic regression analyses were performed for variables associated with lipid-lowering medication (LLM) use and the attainment of low-density lipoprotein-cholesterol (LDL-C) goal.

RESULTS

The study includes 472 subjects with FH (mean age at FH diagnosis: 46±12 years, 61.4% women). A history of premature coronary artery disease was found in 12%. The percentage of LLM use in subjects with a Dutch Lipid Clinic Network score of ≥ 6 (probable or definite FH) in our registry (64%) was slightly lower than the regional data but higher than the global data. Among those who received statins, 25.2% and 6.4% achieved LDL-C levels of ＜100 mg/dL and ＜70 mg/dL, respectively. Women with FH were less likely to achieve LDL-C ＜70 mg/dL (adjusted odds ratio: 0.22, 95% confidence interval: 0.06-0.71, p=0.012).

CONCLUSIONS

FH in Thailand was diagnosed late, and treatment was inadequate for the majority of subjects. Women with FH were less likely to achieve LDL-C goals. Our insights could potentially help raise awareness and narrow the gap in patient care.

Association between Achilles Tendon Softness and Atherosclerotic Cardiovascular Disease in Patients with Familial Hypercholesterolemia

AIMS

Achilles tendon (AT) xanthomas are a specific physical finding of familial hypercholesterolemia (FH) and AT thickness has been used for its diagnosis and evaluation of its severity. Recently, we reported that the AT of FH patients was softer than that of non-FH patients and the combined use of a cut-off value for AT softness with that for AT thickness improved diagnostic accuracy. However, an association between AT softness and severity of atherosclerosis has not been reported. Accordingly, the present study aimed to investigate whether AT softness was associated with carotid atherosclerosis and presence of atherosclerotic cardiovascular disease (ASCVD) in FH.

METHODS

The AT of 176 genetically diagnosed FH patients and 98 non-FH patients was examined to measure AT thickness and the elasticity index (EI) as an indicator for assessing AT softness using ultrasonography.

RESULTS

Increased age was associated with AT softness, and overweight was negatively related to AT softness. There were significant inverse correlations between EI and maximum and mean intima-media thickness (IMT) within the common carotid artery only among FH patients. In multiple linear regression analysis, although the relationship between EI and mean IMT was attenuated, the association between EI and maximum IMT remained robust. In logistic regression analysis adjusted for age, sex and traditional cardiovascular risk factors (smoking history, presence of hypertension, presence of diabetes mellitus, overweight, LDL-cholesterol, HDL-cholesterol, and Log triglycerides), EI was associated with presence of ASCVD (Odds ratio per 1-SD increase, 0.37; 95% CI, 0.15 - 0.86; P=0.0252).

CONCLUSION

The degree of lipid deposition in the AT of FH patients could be assessed by its thickness as well as its softness. AT softness is not only useful in diagnosing FH but is also associated with the severity of carotid atherosclerosis and presence of ASCVD. In addition, these findings suggest that AT softness would be helpful in risk assessment for FH patients.

How Can We Identify Very High-Risk Heterozygous Familial Hypercholesterolemia?

Heterozygous familial hypercholesterolemia (HeFH) is a genetic disorder that elevates low-density lipoprotein cholesterol and increases the risk of premature atherosclerotic cardiovascular disease (ASCVD). However, despite their atherogenic lipid profiles, the cardiovascular risk of HeFH varies in each individual. Their variety of phenotypic features suggests the need for better risk stratification to optimize their therapeutic management. The current review summarizes three potential approaches, including (1) definition of familial hypercholesterolemia (FH)-related risk scores, (2) genetic analysis, and (3) biomarkers. The International Atherosclerosis Society has recently proposed a definition of severe FH to identify very high-risk HeFH subjects according to their clinical characteristics. Furthermore, published studies have shown the association of FH-related genetic phenotypes with ASCVD, which indicates the genetic analysis's potential to evaluate individual cardiovascular risks. Biomarkers reflecting disease activity have been considered to predict the formation of atherosclerosis and the occurrence of ASCVD in HeFH subjects. Incorporating these risk stratifications will be expected to allocate adequate intensity of lipid-lowering therapies in HeFH subjects, which ultimately improves cardiovascular outcomes.

Genetic mutations, regression of Achilles tendon thickness, and cardiovascular events among patients with familial hypercholesterolemia

BACKGROUND AND AIMS

Achilles tendon thickness (ATT) can be regressed through LDL-lowering in patients with familial hypercholesterolemia (FH). We aimed to determine factors associated with regression of ATT and its role in development of major adverse cardiovascular events (MACE).

METHODS

Patients with clinically diagnosed FH (N = 1,050, male/female = 490/560) were retrospectively assessed. FH-related gene mutations and ATT data using X-ray were collected. Multivariable linear regression analysis was exploited to test the factors associated with deterioration of ATT. Cox proportional hazards models were used to assess factors associated with MACE, including cardiovascular death and acute coronary events.

RESULTS

The median follow-up period was 12.6 years. FH-linked mutations were identified in 777 patients. During the follow-up period, 113 MACEs were observed, and median ATT was regressed from 8.7 to 8.5 mm. We found that there was more significant positive correlation between cholesterol-year score and ATT among patients with FH-related gene mutation (p < 2.2 × 10^-16; Spearman's r = 0.42). Multivariable linear regression analyses revealed that age (standardized coefficients [SCs] = 0.307, 95% confidence interval [CI] = 0.241-0.373), hypertension (SCs = 0.069, 95%CI = 0.001-0.138), and diabetes (SCs = 0.059, 95% CI = 0.003-0.115) were positively correlated with changes in ATT (progression). Baseline ATT (SCs = -0.474, 95%CI = -0.535-0.413) and FH-related mutations (SCs = -0.058, 95%CI = -0.091-0.024) were negatively correlated with changes in ATT (regression). Considering this confounding factors, regression of ATT was significantly associated with reduced MACE (hazard ratio [HR] = 0.67, 95%CI = 0.51-0.89, per 1.0 mm).

CONCLUSIONS

Assessed ATT condition and presence of FH-linked gene mutations represent diagnostic values and risk stratification information among patients with FH.

Prospective Registry Study of Primary Dyslipidemia (PROLIPID): Rationale and Study Design

Introduction: Primary dyslipidemias are inherited disorders in plasma lipoprotein metabolism that lead to serious cardiovascular and other complications. The Japanese Ministry of Health, Labor and Welfare (MHLW) covers medical expenses, under the Research Program on Rare and Intractable Diseases, for homozygous familial hypercholesterolemia (FH), familial chylomicronemia, sitosterolemia, cerebrotendinous xanthomatosis, lecithin:cholesterol acyltransferase deficiency, Tangier disease, and abetalipoproteinemia. Apolipoprotein A1 deficiency, heterozygous FH, and type III hyperlipoproteinemia are covered by the MHLW Pediatric Chronic Disease Program. Heterozygous FH and type III hyperlipoproteinemia are also important for their relatively common prevalence and, accordingly, high impact on Japanese public health by significant contribution to the overall prevalence of cardiovascular diseases. Therefore, a systemic survey of these diseases is mandatory to estimate their actual situation, such as prevalence, clinical manifestations, and prognoses among the Japanese population. The impact of these rare and intractable diseases on cardiovascular and other complications will likely be higher among Japanese people than other ethnicities because the general Japanese population has many cardioprotective aspects. The current study intends to conduct a multicenter registry of these diseases to assess their demographics and clinical features comprehensively.

Methods and Analysis: The Prospective Registry Study of Primary Dyslipidemia is a registry-based prospective, observational, multicenter cohort study in Japan, enrolling patients who fulfill the Japanese clinical criteria of the primary dyslipidemias listed above, from 26 participating institutes from August 2015 to March 2023. A total of 1,000 patients will be enrolled in the study and followed for 10 years. Clinical parameters are collected, including physical and laboratory findings, genetic analysis, drugs, lifestyle management, and clinical events, especially cardiovascular events. The primary endpoint of this study is the new onset of cardiovascular disease and acute pancreatitis, and the secondary endpoint is death from any causes.

Ethics and Dissemination: This study complies with the Declaration of Helsinki, the Ethical Guidelines for Medical and Health Research Involving Human Subjects, and all other applicable laws and guidelines in Japan. The institutional review boards have approved this study protocol at all participating institutes. The final results are to be published at appropriate international conferences and in peer-reviewed journals.