Low-Density Lipoprotein Levels and Not Mutation Status Predict Intima-Media Thickness in Familial Hypercholesterolemia

The Effect of Long-Term Atorvastatin Therapy on Carotid Intima-Media Thickness of Children With Dyslipidemia

Carotid intima-media thickness (cIMT) has been proposed as an early marker of subclinical atherosclerosis in high risk children. Children with heterozygous familial hypercholesterolemia have greater cIMT than matched healthy controls or their unaffected siblings. Statin therapy may delay the progression of cIMT, although long-term studies in children are scarce. We evaluated the effect of atorvastatin treatment on cIMT in children with dyslipidemia. We studied 81 children/adolescents, 27 with severe dyslipidemia (low-density lipoprotein cholesterol [LDL-C] ≥190 mg/dL) and 54 sex- and age-matched healthy controls; LDL-C ≤ 130 mg/dL and lipoprotein (a), Lp(a), ≤30 mg/dL. In the children with dyslipidemia, cIMT was measured twice, before and on treatment (18.2 ± 7.7 months). Anthropometric data, a full lipid profile, liver, kidney, and thyroid function were evaluated. Males with dyslipidemia had a greater cIMT than male controls after adjustment for other factors (P = .049). In addition, a nonstatistically significant decrease in cIMT was observed after treatment (P = .261). Treatment with atorvastatin resulted in a significantly improved lipid profile. Females with dyslipidemia had a significantly thinner cIMT than males. Children with normal and high Lp(a) levels had similar cIMT values. In conclusion, treatment with atorvastatin had a beneficial effect on the lipid profile and cIMT progression in children with severe dyslipidemia.

Risk prediction model of dyslipidaemia over a 5-year period based on the Taiwan MJ health check-up longitudinal database

OBJECTIVE

This study aimed to provide an epidemiological model to evaluate the risk of developing dyslipidaemia within 5 years in the Taiwanese population.

METHODS

A cohort of 11,345 subjects aged 35-74 years and was non-dyslipidaemia in the initial year 1996 and followed in 1997-2006 to derive a risk score that could predict the occurrence of dyslipidaemia. Multivariate logistic regression was used to derive the risk functions using the check-up centre of the overall cohort. Rules based on these risk functions were evaluated in the remaining three centres as the testing cohort. We evaluated the predictability of the model using the area under the receiver operating characteristic (ROC) curve (AUC) to confirm its diagnostic property on the testing sample. We also established the degrees of risk based on the cut-off points of these probabilities after transforming them into a normal distribution by log transformation.

RESULTS

The incidence of dyslipidaemia over the 5-year period was 19.1%. The final multivariable logistic regression model includes the following six risk factors: gender, history of diabetes, triglyceride level, HDL-C (high-density lipoprotein cholesterol), LDL-C (low-density lipoprotein cholesterol) and BMI (body mass index). The ROC AUC was 0.709 (95% CI: 0.693-0.725), which could predict the development of dyslipidaemia within 5 years.

CONCLUSION

This model can help individuals assess the risk of dyslipidaemia and guide group surveillance in the community.

Premature Valvular Heart Disease in Homozygous Familial Hypercholesterolemia

Valvular heart disease frequently occurs as a consequence of premature atherosclerosis in individuals with familial hypercholesterolemia (FH). Studies have primarily focused on aortic valve calcification in heterozygous FH, but there is paucity of data on the incidence of valvular disease in homozygous FH. We performed echocardiographic studies in 33 relatively young patients (mean age: 26 years) with homozygous FH (mean LDL of 447 mg/dL, 73% on LDL apheresis) to look for subclinical valvulopathy. Twenty-one patients had evidence of valvulopathy of the aortic or mitral valves, while seven subjects showed notable mitral regurgitation. Older patients were more likely to have aortic valve calcification (>21 versus ≤21 years: 59% versus 12.5%; p = 0.01) despite lower LDL levels at the time of the study (385 versus 513 mg/dL; p = 0.016). Patients with valvulopathy were older and had comparable LDL levels and a lower carotid intima-media thickness. Our data suggests that, in homozygous FH patients, valvulopathy (1) is present across a wide age spectrum and LDL levels and (2) is less likely to be influenced by lipid-lowering treatment. Echocardiographic studies that focused on aortic root thickening and stenosis and regurgitation are thus likely an effective modality for serial follow-up of subclinical valvular heart disease.

Identification and characterization of severe familial hypercholesterolemia in patients presenting for cardiac catheterization

BACKGROUND

Patients with severe familial hypercholesterolemia (FH) are often unrecognized despite typical presentation. The introduction of PCSK9 inhibitors opens new therapeutic options and emphasizes the need for identification of severe FH patients.

OBJECTIVES

The objective was identification, characterization, and management of severe FH patients by screening of cardiac catheterization (CC) database.

METHODS

Retrospective analysis of CC database from 2002 to mid-2015 was performed for low-density lipoprotein cholesterol (LDL-C) ≥130 mg/dL (n = 2383). Severe FH was diagnosed if any prior LDL-C was ≥280 mg/dL, excluding secondary causes. Peak/current LDL-C levels and lipid-lowering therapies were evaluated. Initial attempt was made to detect relatives with FH according to identifying data and age-dependent LDL-C cutoffs.

RESULTS

Severe FH was identified in 54 of initial 2382 patients with CC LDL-C ≥130 mg/dL. Mean age at cardiovascular disease diagnosis was 45 years. Peak LDL-C was 280 to 464 mg/dL (median, 322). Coronary artery bypass graft surgery was performed in 26 patients (48%) and redo coronary artery bypass graft surgery in 5 patients (9%). Risk factors included obesity (33%), hypertension (59%), smoking (33%), and diabetes (24%). LDL-C reduction ≥50% of peak value was achieved in 56%, LDL-C <130 mg/dL in 32%, and LDL-C <100 mg/dL in 17% of patients. High-intensity statin plus ezetimibe was prescribed for 67%, high-intensity statin alone for 24%, and other lipid-lowering therapies for 9% of patients. Treatment intensity was directly associated with attainment of LDL-C goals. Matching probands' surnames and place of residency with district health maintenance organization database has identified 161 additional individuals with possible FH; 58% were not treated with lipid-lowering drugs.

CONCLUSIONS

A simple algorithm for identification of patients with severe FH was implemented based on large catheterization and health maintenance organization databases and revealed patients with severe FH and coronary disease at a young age, with low attainment of cholesterol treatment goals. Screening existing cardiovascular databases of populations at risk will promote identification and management of severe FH patients and their affected family members.

Variable expressivity and co-occurrence of LDLR and LDLRAP1 mutations in familial hypercholesterolemia: failure of the dominant and recessive dichotomy

BACKGROUND

The familial inherited genetic disorder of lipoprotein metabolism affects more than 10 million individuals around the world. Lebanon is one of the several endemic areas for familial hypercholesterolemia (FH) with a founder mutation in the low-density lipoprotein cholesterol receptor (LDLR) gene, responsible for most of the cases. We have previously shown that 16% of all familial cases with hypercholesterolemia do not show genotype segregation of LDLR with the underlying phenotype.

METHODS

We used Sanger sequencing to genotype 25 Lebanese families with severe FH for the gene encoding the LDLR-associated protein (LDLRAP1), responsible for the recessive form of the disease starting with the four families that did not show any genotype-phenotype correlation in our previous screening.

RESULTS

We showed that the previously reported p.Q136* variant is linked to the hypercholesterolemia phenotype in the four families. In addition, we showed a variable phenotype between families and between members of the same family. One family exhibits mutations in both LDLR and LDLRAP1 with family members showing differential phenotypes unexplained by the underlying genotypes of the two genes.

CONCLUSION

The p.Q136* variant in LDLRAP1 is yet another founder mutation in Lebanon and coupled with the LDLR p.C681* variant explains all the genetic causes of FH in Lebanon.