Achilles Tendon Thickness Assessed by X-ray Predicting a Pathogenic Mutation in Familial Hypercholesterolemia Gene

A Japanese Case of Familial Hypercholesterolemia with a Protein-truncating Variant in LDLR and a PCSK9 Variant without Significant Atherosclerosis but Showing Remarkable Achilles Tendon Thickening

The patient was a 54-year-old woman with familial hypercholesterolemia and remarkable Achilles tendon thickening. At 20 years old, the patient had a total cholesterol level of approximately 300 mg/dL. She started receiving rosuvastatin (5 mg/day) for low-density lipoprotein cholesterol (LDL-C) 235 mg/dL at 42 years old, which was increased to 10 mg/day at 54 years old, decreasing her serum LDL-C level to approximately 90 mg/dL. The serum Lp (a) level was 9 mg/dL. A computed tomography coronary angiogram showed no significant stenosis. Next-generation sequencing revealed a frameshift variant in LDL receptor (LDLR) (heterozygous) and a missense variant in proprotein convertase subtilisin/kaxin type 9 (PCSK9) (heterozygous). Continued statin therapy, in addition to low Lp (a) and female sex, can help prevent cardiovascular disease.

Impact of changes in Achilles tendon thickening on cardiovascular events in patients with familial hypercholesterolemia

Background

Achilles tendon thickening (ATT) can be ameliorated by lowering low-density lipoprotein (LDL) levels in patients with familial hypercholesterolemia (FH). The Japan Atherosclerosis Society (JAS) defines ATT as ≥8.0 mm in males and ≥7.5 mm in females. We aimed to determine the clinical impact of changes in ATT on the development of major adverse cardiovascular events (MACE).

Methods

Patients with clinically diagnosed heterozygous FH (HeFH) (N = 1273; 614 males, 659 females) with ATT data from X-ray were assessed. Patients were divided into four groups: patients without ATT from baseline until follow-up (group 1), patients without ATT at baseline but developed ATT at follow-up (group 2), patients with ATT at baseline but regressed at follow-up (group 3), and patients with ATT from baseline until follow-up (group 4). Cox proportional hazard models were used to assess the factors associated with MACE, including cardiovascular death and any coronary events.

Results

On follow-up (median: 10.9 years), 142 MACEs were observed, and the median ATT regressed from 7.8 to 7.6 mm. Changes in ATT were significantly associated with the occurrence of MACE in all groups, when compared to group 1 (hazard ratio [HR]: 2.73; 95 % confidence interval [CI]: 1.33-4.13 [p < 0.001], HR: 2.18, 95 % CI: 1.08-3.28, [p < 0.001], HR: 6.34, 95 % CI: 3.10-9.58, [p < 0.001], in groups 2, 3, and 4, respectively).

Conclusions

Assessing ATT has diagnostic value and allows for risk stratification among patients with HeFH.

Validation of the 2022 Clinical Diagnostic Criteria of Familial Hypercholesterolemia in Japan

AIM

In 2022, the Japan Atherosclerosis Society (JAS) has revised its clinical diagnostic criteria of familial hypercholesterolemia (FH) and adopted the use of definite, probable, possible, and unlikely FH according to the Dutch Lipid Clinic Network (DLCN) FH criteria. However, these strata have not been validated and their impact on coronary artery disease (CAD) is yet to be elucidated.

METHODS

In this study, we retrospectively examined the patients with FH aged ≥ 15 years (N=857, male=431) who were admitted to Kanazawa University Hospital between 2010 and 2022. We assessed the prevalence of patients with a pathogenic variant as FH and odds ratio (OR) of CAD among each group determined by the JAS criteria 2022 for adults.

RESULTS

In total, 414, 128, 142, and 173 patients were found to have definite, probable, possible, and unlikely FH, respectively, in this population. The prevalences of patients with a pathogenic variant as FH were 77.1%, 28.7%, 13.0%, and 1.2 %, respectively, among the definite, probable, possible, and unlikely FH patients (P-trend ＜0.001). Compared with the reference group of unlikely FH, patients with definite, probable, and possible FH were noted to have significantly higher adjusted odds of developing CAD (OR, 9.1; 95% confidence interval [CI], 3.2-12.6; P＜0.001 and OR, 4.2; 95% CI, 1.7-6.4; P＜0.001, and OR, 2.8; 95% CI, 1.2-4.4; P=0.002, respectively).

CONCLUSION

The new JAS diagnostic criteria for FH have been noted to work well in terms of diagnosing definitive, probable, or possible FH patients. Thus, it is seen to be of great help in terms of risk discrimination.

Achilles tendon thickness normalized to body surface area as a marker of asymptomatic peripheral arterial disease

OBJECTIVES

The normalisation of Achilles tendon thickness (ATT) to anthropometric parameters may increase the diagnostic efficiency of the assessment of ATT. The aim of this study was to compare the diagnostic value of AT dimensions depending on their normalization to body surface area (BSA) in patients with asymptomatic peripheral arterial disease (PAD).

METHODS

All patients underwent duplex scanning of the carotid arteries and the lower limb arteries. Asymptomatic PAD was defined as the presence of ≥50% stenosis in the carotid and/or lower limb arteries. ATT was measured using a longitudinal scan, width (ATW) and cross-sectional area (AT CSA), which was determined during a cross-sectional scan.

RESULTS

The study included 369 patients, among whom asymptomatic PAD was detected in 18 (4.88%) patients. Only the ATT demonstrated diagnostic value for asymptomatic PAD. After normalizing the size of the AT to the BSA, the diagnostic performance of ATT, ATW and AT CSA became statistically significant. Among the studied parameters, only an increase in ATT/BSA >0.29 cm/m2 was associated with a significant increase in the odds ratio (OR) of asymptomatic PAD by 4.11 times (95% CI 1.08-15.7; p = .038) after adjustments.

CONCLUSION

An increase in ATT/BSA >0.29 cm/m2 predicted the presence of asymptomatic PAD with a sensitivity of 61.1% and a specificity of 77.9%. ATT/BSA values of less than 0.29 cm/m2 made it possible to exclude asymptomatic PAD with a probability of 97.5%. An increase in ATT/BSA >0.29 cm/m2 was associated with a 4.11-fold increase in the OR of asymptomatic PAD (95% CI 1.08-15.7).

Familial hypercholesterolemia with special focus on Japan

Familial hypercholesterolemia (FH) is an inherited disorder characterized by increased low-density lipoprotein LDL) cholesterol and atherosclerotic cardiovascular disease. Although initial genetic analysis linked FH to LDL receptor mutations, subsequent work demonstrated that a gain-of-function mutation in the proprotein convertase subtilisin/kexin type 9 (PCSK9), which causes LDL-R degradation, was shown to be the cause of FH. In this review, we describe the history of research on FH, its clinical phenotyping and genotyping and advances in treatment with special focus on Japan.

Association of cumulative low-density lipoprotein cholesterol exposure with vascular function

BACKGROUND

The relationship between cumulative low-density lipoprotein cholesterol (LDL-C) exposure and progression of atherosclerosis remains uncertain.

OBJECTIVE

The aim of this study was to determine the relationship between cumulative LDL-C level and flow-mediated vasodilation (FMD), nitroglycerine-induced vasodilation (NID) and the presence of plaque in the common carotid artery (CCA).

METHODS

This was a cross-sectional study. We measured FMD in 8208 subjects, NID in 1822 subjects, and CCA plaque in 591 subjects who were not taking lipid-lowering drugs. The subjects were divided into four groups based on cumulative LDL-C exposure: <4000 mg·year/dL, 4000-4999 mg·year/dL, 5000-5999 mg·year/dL, and ≥6000 mg·year/dL.

RESULTS

The odds ratio of the lower quartile of FMD in the cholesterol-year-score <4000 mg·year/dL group was significantly higher than the odds ratios in the other groups. The odds ratio of the lower quartile of NID in the <4000 mg·year/dL group was significantly higher than the odds ratios in the 5000-5999 mg·year/dL and ≥6000 mg·year/dL groups. The odds ratio of the prevalence of CCA plaque in the <4000 mg·year/dL group was significantly higher than that in the ≥6000 mg·year/dL group.

CONCLUSIONS

Endothelial dysfunction occurred from cumulative LDL-C exposure of 4000 mg·year/dL, vascular smooth muscle dysfunction occurred from cumulative LDL-C exposure of 5000 mg·year/dL, and prevalence of CCA plaque occurred from cumulative LDL-C exposure of 6000 mg·year/dL. CLINICAL TRIAL REGISTRY INFORMATION: http://www.umin.ac.jp (UMIN000012950, UMIN000012951, and UMIN000012952, UMIN000003409).

Achilles Tendon Thickening as a Risk Factor of Cardiovascular Events after Percutaneous Coronary Intervention

AIM

The Achilles tendon (AT) thickening may be affected by several factors (e.g., lipid disorders or age). This study aims to determine the prevalence rate of AT thickening in patients with coronary artery disease (CAD) and investigate the correlation between AT thickening and the incidence of major adverse cardiovascular events (MACE) after percutaneous coronary intervention (PCI).

METHODS

The clinical records of 887 patients who had undergone successful PCI and measured Achilles tendon thickness (ATT) using soft X-ray radiographs were retrospectively examined. Subjects were divided into two groups depending on the presence or absence of AT thickening. AT thickening was defined as having ATT of ＞8.0 and ＞7.5 mm in men and women, respectively. Among the two groups, the incidence of MACE was measured for a maximum of 5 years after PCI. MACE was defined as cardiovascular mortality, nonfatal myocardial infarction, or revascularization due to restenosis or the increase of stenosis in other lesions.

RESULTS

This study found that 241 (27.2%) patients have AT thickening. Patients with AT thickening had higher low-density lipoprotein cholesterol (LDL-C) levels. In addition, the Kaplan-Meier curve with a log-rank test demonstrated that patients with AT thickening had a significantly higher incidence of MACE. Furthermore, the multivariate analysis indicated that the presence of AT thickening was independently correlated with the incidence of MACE after PCI.

CONCLUSION

A high percentage of patients with CAD were found to have AT thickening. In addition, the presence of AT thickening was significantly associated with a higher incidence of MACE, independent of LDL-C levels.

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.

Effects of Different Types of Pathogenic Variants on Phenotypes of Familial Hypercholesterolemia

Objective: It has been shown that pathogenic variants are associated with poor clinical outcomes in patients with familial hypercholesterolemia (FH). However, data on the effect of different types of pathogenic variants on FH phenotype is limited.

Methods: We retrospectively investigated the associations between genotypes and phenotypes, including low-density lipoprotein (LDL) cholesterol level and the occurrence of major adverse cardiac events (MACEs), defined as cardiovascular death, myocardial infarction, unstable angina, or coronary artery revascularization, in patients with FH (N = 1,050, male/female = 490/560). Based on genotype, the patients were divided into the following three groups: patients without pathogenic variants, patients with missense variants, and patients with protein-truncating variants (PTVs). Cox proportional hazard model was used to identify the factors associated with MACEs.

Results: The median follow-up duration was 12.6 years (interquartile range = 9.5–17.9 years). There were 665 patients with FH-mutation (277 patients with missense variants and 388 patients with PTVs) and 385 patients without FH-mutation. Over the follow-up duration, 175 MACEs were observed. We identified 89 different pathogenic variants in the 665 patients with FH. LDL cholesterol level was found to be significantly higher in patients with PTVs (256 mg/dl) than in patients with missense variants (236 mg/dl) and patients without pathogenic variants (216 mg/dl). It was also found that PTVs and missense variants are significantly associated with MACEs (hazard ratio [HR] = 1.58, 95% confidence interval [CI] = 1.08–2.08, p = 0.0033 and HR = 3.24, 95% CI = 2.12–4.40, p = 3.9 × 10⁻⁶, respectively), independent of classical risk factors.

Conclusion: Pathogenic variants, especially PTVs, are significantly associated with poor outcomes in patients with FH. Genetic testing is useful for the diagnosis and risk stratification of patients with FH.

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.

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.