Coronary disease in familial hypercholesterolemia

Defining patients at extremely high risk for coronary artery disease in heterozygous familial hypercholesterolemia

AIM

Heterozygous patients with familial hypercholesterolemia (FH) are known to be associated with a high risk of coronary artery disease (CAD), which is a major determinant of their clinical outcome. The prognosis of heterozygous FH patients substantially varies, being dependent on the level of their CAD risk, and their therapeutic regimen should be individualized. We assessed critical levels of LDL-cholesterol (LDL-C) and Achilles tendon thickness (ATT) to identify heterozygous FH patients at "very high" risk for CAD.

METHODS

One hundred and nine heterozygous FH patients who had no history of CAD and had had their plasma lipid profile and ATT assessed before treatment were followed up until their first CAD event or 31 December 2010. Multivariable logistic regression models were used to analyze the correlation of LDL-C and/or ATT levels with the risk of developing CAD.

RESULTS

During the follow-up period, 21 of the 109 patients had a CAD event, diagnosed by coronary angiogram. Individuals in the highest tertile of LDL-C had a CAD risk 8.29-fold higher than those in the lowest tertile. Individuals in the highest tertile of the ATT group had a 7.82-fold higher CAD risk than those in the lowest tertile. Those who had either LDL-C ≥ 260 mg/dL or ATT ≥ 14.5 had a 23.94-fold higher CAD risk than those with LDL-C < 260 mg/dL and ATT <14.5 mm.

CONCLUSIONS

In heterozygous FH patients, LDL-C 260 mg/dL or higher and/or ATT 14.5 mm or thicker are useful markers for extracting patients at "very high" risk for CAD.

Cholesterol-years score is associated with development of senile degenerative aortic stenosis in heterozygous familial hypercholesterolemia

We retrospectively evaluated the frequency and identified the factors associated with the development of aortic stenosis (AS) in 96 patients with heterozygous familial hypercholesterolemia (FH). The frequency of AS was 31% (4/13) and that of critical stenosis was 15% (2/13) in older patients over the age of 70 years. All 4 patients with AS were female aged more than 70 years who were diagnosed with FH when aged more than 60 years. There were no significant differences in conventional coronary risk factors; however, the age at cardiac catheterization, age at diagnosis of FH and the cholesterol-years score (CYS) with AS were significantly higher than those without AS (p=0.006, p=0.017, p=0.021, respectively). In multiple regression analysis, CYS was a significant independent predictor for the development of AS (p=0.037) in 13 older patients over the age of 70 years. These results suggest that physicians should be aware that AS needs attention in older patients with heterozygous FH, especially women who have been diagnosed late in life and those who have been inadequately treated.

Serum noncholesterol sterols in children with heterozygous familial hypercholesterolemia undergoing pravastatin therapy

OBJECTIVE

To assess causes for insufficient cholesterol-lowering response to pravastatin and plant stanol esters in children with heterozygous familial hypercholesterolemia (HeFH).

STUDY DESIGN

Nine of 16 children with HeFH who had not reached normocholesterolemia (< or =194 mg/dL [< or =5 mmol/L]) by 1 year after treatment (40 mg pravastatin and plant stanol ester) were called nonresponders. The 7 remaining children were responders. Serum noncholesterol sterol ratios (10(2) x mmol/mol of cholesterol), surrogate estimates of cholesterol absorption (cholestanol, campesterol, sitosterol) and synthesis (desmosterol and lathosterol), were studied at study baseline (on plant stanol esters) and during combination therapy with pravastatin and plant stanol esters.

RESULTS

Pravastatin decreased the serum levels of cholesterol and cholesterol synthesis markers, and increased the ratios of cholesterol absorption markers. Compared with the responders, the nonresponders had higher study baseline (on plant stanol esters) serum cholesterol concentrations (299 +/- 39 vs 251 +/- 35 mg/dL [7.7 +/- 1.0 vs 6.5 +/- 0.9 mmol/L]; P <.001) and higher respective ratios of campesterol (371 +/- 99 vs 277 +/- 67 10(2) x mmol/mol of cholesterol; P = .049) and sitosterol (176 +/- 37 vs 126 +/- 24 10(2) x mmol/mol of cholesterol; P = .008). The higher the ratio of cholestanol at study baseline, the smaller the 1-year percent reduction in cholesterol (r = .556; P = .025).

CONCLUSIONS

Pravastatin treatment increases the markers of cholesterol absorption and decreases those of cholesterol synthesis in HeFH during simultaneous inhibition of cholesterol absorption. Combined inhibition of cholesterol absorption and synthesis may not normalize serum lipids in those patients with the highest cholesterol levels, especially if signs of enhanced cholesterol absorption are detectable.

A review on the diagnosis, natural history, and treatment of familial hypercholesterolaemia

BACKGROUND

Familial hypercholesterolaemia (FH) affects approximately 1 in 500 people (10 million world-wide) and the elevated serum cholesterol concentrations lead to a more than 50% risk of fatal or non-fatal coronary heart disease by age 50 years in men and at least 30% in women aged 60 years. Based on a systematic literature search, we review the natural history of FH, describe the diagnostic criteria, and consider the effectiveness of treatment.

METHODS

A comprehensive review was conducted of the literature on the diagnosis of FH, the morbidity and mortality related to treated and untreated FH, and the evidence on the effectiveness of treatment of FH in adults and children. Treatment options have changed since statin treatment became available, and we have not considered pre-statin therapy studies of treatment effectiveness.

FINDINGS AND DISCUSSION

A clinical diagnosis of FH is widely used, but a definitive diagnosis can be made by genetic screening, although mutations are currently only detected in 30-50% of patients with a clinical diagnosis. Under-diagnosis of FH has been reported world-wide ranging from less than 1% to 44%. The relative risk of death of FH patients not treated with statins is between three and fourfold but treatment is effective, and delays or prevents the onset of coronary heart disease. Early detection and treatment is important. Aggressive LDL therapy is more effective in the regression of the carotid intima media thickness than conventional LDL therapy. Diagnosis at birth is problematic, and should be delayed until at least 2 years of age. Statins are not generally recommended for the treatment of children up to adolescence. Resins may be used but poor adherence is a problem. Technical advances in mutation detection, and the identification of other genes that cause FH, are likely to have important implications for the cost effectiveness of genetic diagnosis of FH.

Is there a genetic basis for resistance to atherosclerosis?

Atherosclerosis and its major clinical manifestation, coronary heart disease, is and will remain the main cause of mortality. Reviews on this subject dealt with factors that enhance development of atherosclerosis. This review deals with a new facet, that some individuals are less prone to develop atherosclerosis: (1) despite high cholesterol intake or (2) despite hypercholesterolemia with elevated low-density lipoprotein cholesterol (LDL-C) levels. The variability of response of plasma cholesterol to dietary intake was shown to be regulated by liver x receptor (LXR) that determines the rate of intestinal cholesterol absorption through the ATP-binding cassette (ABC) gene family. Other gene products, such as apolipoprotein-E (apo-E), scavenger receptor-B1 (SR-B1) and acyl coenzyme: cholesterol acyltransferase-2 (ACAT-2) affect cholesterol absorption also. The role of a genetic background for relative resistance to atherosclerosis is highlighted by subjects with familial hypercholesterolemia in whom high plasma cholesterol levels has not curtailed their expected life span. Studies in animals have shown that resistance to atherosclerosis in spite of hypercholesterolemia is affected by factors such as high-density lipoprotein (HDL) phospholipids that enhance reverse cholesterol transport, non-responsiveness to induction or lack of monocyte chemotactic protein-1 (MCP-1), C-C chemokine receptor 2 (CCR2), macrophage colony stimulating factor (MCSF), or vascular cell adhesion molecule-1 (VCAM-1). Since macrophages have been regarded as pro- or anti-atherogenic, evidence was collated that the high activity of scavenger receptors may contribute towards resistance to atherosclerosis if accompanied by adequate amounts of apo-E for cholesterol removal.

Coronary heart disease, hypercholesterolemia, and atherosclerosis. I. False premises

Lipid-rich caseous debris of advanced lesions stimulated interest in the role of cholesterol and lipids in atherosclerosis. Lipid-containing arterial lesions in cholesterol-overfed animals (cholesterolosis) and xanthomatous vascular lesions in subjects with familial hypercholesterolemia were then misrepresented as being atherosclerotic and led to the development of the hypercholesterolemic/lipid hypothesis. It is untenable that cholesterol, an essential multifunctional metabolite, is pathogenic at all blood levels and hypercholesterolemia is not prerequisite for human or experimental atherosclerosis. Serum cholesterol levels display a poor correlation with atherosclerosis at autopsy and with unreliable national coronary heart disease (CHD) mortality in each sex. Atherosclerosis topography and its iatrogenic production in humans and experimentally in herbivores by hemodynamic means both support a biomechanical causation and preclude causality by any circulating humoral factor. CHD, not a specific disease, is a nonspecific complication of many diseases including atherosclerosis and cannot be equated with coronary atherosclerosis due to differences in pathology and pathogenesis. Thus, extrapolations from CHD risk factors or correlations with fallacious vital statistics to atherosclerosis are invalid. It follows that the hypercholesterolemic/lipid hypothesis evolving from false premises, misuse of CHD, scientific misrepresentation, and fallacious data has no legitimate basis.

Coronary heart disease, hypercholesterolemia, and atherosclerosis. II. Misrepresented data

Early development of the hypercholesterolemic/lipid hypothesis of atherosclerosis was based on false premises including fallacious national mortality rates and misrepresentation of the vascular lesions in cholesterol-overfed animals and monogenic hypercholesterolemias (MH). Nonspecific coronary heart disease (CHD) was inappropriately used as a surrogate of atherosclerosis, unmeasured and unseen. Causality was assumed and implied by classifying statistical correlates of CHD as atherogenic risk factors. These faults were compounded by methodological errors, pooling of all causes of CHD, a large clinical diagnostic error, biased age selection of cohorts leading to confounding by age and MH, and emphasis on population and cohort mean values which conceal heterogeneity within cohorts and are inapplicable to individuals. Overzealous investigators neglected to review the premises and relevant pathology on which the hypothesis was based or to reconcile valid criticisms, inconsistencies, and invalidation of CHD epidemiology by pathological, experimental, and iatrogenic evidence. Statistical data, pertaining to CHD but with no scientific applicability to atherosclerosis, progressively imparted to readers a misleading perception of the relationship of serum cholesterol to CHD. Concurrently the statistical serum cholesterol range was unjustifiably abandoned. The evidence establishes that the lipid hypothesis of atherosclerosis lacks scientific basis.

Additional risk factors influence excess mortality in heterozygous familial hypercholesterolaemia

Life expectancy of patients with familial hypercholesterolaemia is decreased. Some untreated patients reach a normal life span and, therefore, additional risk factors and the type of mutation in the low-density lipoprotein (LDL) receptor gene are likely to influence the clinical outcome. We determined all cause mortality in kindreds with the disorder, who were untreated, in order to study (a) additional risk factors for coronary artery disease (CAD) and (b) the types of LDL receptor gene mutations that may contribute to a poor prognosis. The mortality in all 855 first-degree relatives of 113 unrelated patients was compared to the Dutch population after standardisation for age, gender, and calendar period. Analyses restricted to affected relatives could have underestimated the mortality risk due to lack of information about severe cases, who died prematurely. Therefore, all first-degree relatives were analysed and as a result the standardised mortality ratios (SMRs) exhibit only 50% of the excess mortality from familial hypercholesterolaemia. We observed 190 deaths in 32048 person-years leading to an overall SMR of 1.34 (95% confidence interval (CI) 1. 16-1.55, P=0.001). High excess mortality occurred in males between age 40 and 54 (SMR 2.34, 95% CI 1.60-3.31, P<0.001). The excess mortality decreased during the last decades. This change of mortality over calendar time shows that additional risk factors modulate the mortality from the disorder. The SMR of 62 families referred with premature CAD was 1.62 (95% CI 1.32-1.93, P<0.001) and the SMR was 1.10 (95% CI 0.86-1.34, P=0.4) in 51 families without premature CAD. The mortality risk of kindreds with null alleles was similar to that of kindreds with other mutations. In conclusion, the burden of the untreated disorder occurred mainly among middle-aged males and was not influenced by the type of mutation. Additional risk factors increased excess mortality significantly and are highlighted by the presence of premature CAD among first-degree relatives. This underscores the need for active identification of all hypercholesterolaemic relatives of such patients.

Characteristic cardiovascular manifestation in homozygous and heterozygous familial hypercholesterolemia

BACKGROUND

The aortic valve dysfunction of patients with homozygous familial hypercholesterolemia (FH) suggests that hypercholesterolemia affects not only coronary arteries but also the aortic valve. We studied the aortic root of patients with homozygous FH and those of patients with heterozygous FH to characterize the premature atherosclerotic lesions by using histopathologic specimens.

METHODS AND RESULTS

The aortic roots of 10 patients with homozygous FH, age 9 to 58 years, were studied by cardiac catheterization with several angiographies. The aortic roots of 39 patients with heterozygous FH under age 60 years were also examined for aortic and mitral valvular functions by color Doppler echocardiography, and 30 normocholesterolemic patients with coronary artery disease were examined as control subjects. In addition, in 22 patients with FH and 20 control subjects, the internal diameter of the aortic annulus and the aortic ridge in cardiac cycles were measured. Of the 10 homozygotes with FH, 8 patients had aortic regurgitation demonstrated by aortography; 3 of them showed significant transvalvular pressure gradients. Stenotic changes of coronary ostia were observed in 8 of the 10 homozygotes with moderate coronary atherosclerosis. Of the 39 heterozygotes with FH, 10 patients had aortic regurgitation shown by Doppler echocardiography, as did only 1 of the 30 control subjects (P <.05). The average diameter and distensibility of the ascending aorta were significantly reduced in the heterozygotes compared with the control subjects. The surgically resected cusp specimens of aortic valves obtained from 1 homozygous and 1 heterozygous patient showed significant thickening of the cusp with foam cell infiltration.

CONCLUSIONS

Premature atherosclerosis in FH had a characteristic distribution, affecting the aortic root dominantly. The involvement of the aortic valve indicating "hypercholesterolemic valvulopathy" was a peculiar feature of FH, especially its homozygous form, but was reminiscent of ubiquitous processes caused by hypercholesterolemia.

Effects of pravastatin on thoracic aortic atherosclerosis in patients with heterozygous familial hypercholesterolemia

Data regarding the effects of plasma lipid lowering on the evolution of thoracic aortic atherosclerosis (TAA) are scarce. In this study, we performed transesophageal echocardiography to characterize TAA in 16 newly diagnosed patients with heterozygous familial hypercholesterolemia and to follow its evolution after 2 years of statin treatment. TAA was graded as follows: grade I = normal intima; grade II = increased intimal echo density without thickening; grade IIIA = increased intimal echo density with single atheromatous plaque < or = 3 mm; grade IIIB = multiple plaques < or = 3mm; grade IV = > or = 1 plaque >3 mm; and grade V = mobile or ulcerated plaques. Baseline aortic intimal morphology was grade I in one patient, grade II in 4, grade IIIA in 6, grade IIIB in 3, and grade IV in 2 patients. Hypolipidemic treatment resulted in significant reductions in plasma total cholesterol and low-density lipoprotein (LDL) cholesterol. Follow-up aortic morphology was grade I in 5 patients, grade II in 2, grade IIIA in 3, grade IIIB in 3, and grade IV in 3 patients. TAA remained stable in 7 patients, progressed in 3, and regressed in 6 patients. TAA evolved in a uniform manner in the ascending aorta, aortic arch, and descending aorta. Patients with TAA regression were younger (39+/-14 vs 52+/-8 years, p=0.038) and had a greater decrease in plasma LDL cholesterol as a result of treatment (138+/-56 vs 73+/-55 mg/dl, p=0.036) than patients with TAA stability or progression. These observations support the hypothesis that hypolipidemic treatment may favorably affect the course of TAA in patients with heterozygous familial hypercholesterolemia.

Impaired myocardial vasodilation during hyperemic stress with dipyridamole in hypertriglyceridemia

OBJECTIVES

This study sought to investigate the specific role of hypertriglyceridemia in the myocardial hyperemic stress with dipyridamole/rest flow ratio (MDR).

BACKGROUND

Reduced MDR has been reported in hypercholesterolemic patients without evidence of ischemia. However, the specific role of hypertriglyceridemia in MDR has not been studied.

METHODS

Fifteen nondiabetic normocholesterolemic hypertriglyceridemic patients and 13 age-matched control subjects were studied. Myocardial blood flow (MBF) during dipyridamole administration and baseline MBF in hypertriglyceridemic patients and control subjects were measured using positron emission tomography and nitrogen-13 ammonia, after which the MDR was calculated.

RESULTS

Baseline MBF (ml/min per 100 g heart weight) in hypertriglyceridemic patients (mean +/- SD 73.6 +/- 24.1) did not differ significantly from that in control subjects (81.6 +/- 37.2). MBF during dipyridamole loading in hypertriglyceridemic patients (198 +/- 106) was significantly reduced compared with that in control subjects (313 +/- 176, p < 0.05), as was the MDR (2.71 +/- 1.07 vs. 3.73 +/- 1.14, respectively, p < 0.05). Spearman rank-order correlation analysis showed a significant relation between plasma triglyceride concentration and MDR (r = -0.466, asymptotic SE 0.157, p = 0.0125); however, no such significant relation was seen between total plasma cholesterol concentration and MDR (r = -0.369, asymptotic SE 0.130, p = 0.059).

CONCLUSIONS

Impaired myocardial vasodilation was suggested in hypertriglyceridemic patients without symptoms and signs of ischemia.

The in vitro effect of ridogrel on platelet function in normocholesterolaemic and familial hypercholesterolaemic type IIa subjects

Platelets from familial hypercholesterolaemia type IIa patients are hyperreactive and produce increased amounts of thromboxane A2. These modifications of platelet function may play an important role in the occurrence of premature atherosclerosis. One approach to the prevention of the thromboembolic complications of atherosclerosis is the use of antiplatelet agents which depress platelet function. Ridogrel, a combined thromboxane synthase inhibitor and thromboxane A2/prostaglandin endoperoxide receptor blocker inhibits platelet aggregation. This study was designed to investigate the in vitro effect of ridogrel on platelet function in normocholesterolaemic and familial hypercholesterolaemia type IIa subjects. In citrated platelet rich plasma ridogrel significantly inhibited platelet aggregation and thromboxane A2 production in response to collagen, ADP and arachidonic acid stimulation. In washed platelets ridogrel significantly decreased aggregation and serotonin release. Ridogrel significantly increased cAMP levels in response to thrombin stimulation. In conclusion, ridogrel at low concentrations significantly inhibited the in vitro function of platelets in a dose dependant manner in both normocholesterolaemic subjects and familial hypercholesterolaemia IIa subjects.

Characteristics of coronary artery disease and lipoprotein abnormalities in patients with heterozygous familial hypercholesterolemia associated with diabetes mellitus or impaired glucose tolerance

Familial hypercholesterolemia (FH) is a genetic disorder characterized by high levels of serum low density lipoprotein (LDL) cholesterol and premature coronary atherosclerosis. In order to elucidate the influence of abnormal glucose metabolism on the development of coronary artery disease (CAD) in FH patients, we examined the prevalence of CAD and characteristics of lipoprotein abnormalities in patients with heterozygous FH who were accompanied by diabetes mellitus (DM) or impaired glucose tolerance (IGT). The subjects of the present study were 150 patients with heterozygous FH, all over 40 years of age. Oral glucose tolerance tests demonstrated that 15 patients had DM and 27 had IGT. The combination of DM or IGT with FH was associated with a further increase in the prevalence of CAD (DM:IGT:normal glucose tolerance (N), 87:59:43%). Furthermore, the prevalence of the stenoses in the distal coronary arteries was significantly higher in the DM group than in the N group, while there was no significant difference in the prevalence of proximal and middle lesions. Serum triglyceride levels were significantly higher in the DM and IGT groups than in the N group (P < 0.01, DM versus N group; P < 0.01, IGT versus N group), while total cholesterol levels were not significantly different. When lipoproteins were analyzed by polyacrylamide gel electrophoresis, the frequency of midband appearance, which implies an increase in remnant lipoproteins, was significantly higher in the DM and IGT groups than in the N group (DM:IGT:N, 87:72:29%, P < 0.01, DM versus N group; P < 0.01, IGT versus N group). Ultracentrifugation analysis of lipoproteins revealed that intermediate density lipoprotein cholesterol was increased in DM and IGT groups compared with the N group. These data suggest that abnormal glucose metabolism may accelerate the development of CAD in FH patients due to an increase in atherogenic remnant lipoproteins in addition to high concentration of LDL. Special attention should be paid in the treatment of FH patients with impaired glucose metabolism, to avoid the advancement of coronary atherosclerosis.

Results and efficacy of public screening for hypercholesterolemia: the Bavarian Cholesterol Screening Project

Hypercholesterolemia is a risk factor for the development of coronary disease. It does not present with symptoms and can be diagnosed by laboratory examination only. Screening is the only means to detect subjects at risk at a time when preventive measures can effectively be applied. We therefore initiated the Bavarian Cholesterol Screening Project (BCSP). Occasional screening was performed in 150,089 subjects (81,286 women, 68,803 men) in 214 campaigns. The mean cholesterol value was 243 +/- 52 mg/dl for women and 231 +/- 53 mg/dl for men; 37.3% of women and 38.1% of men had values of 201-250 mg/dl, 42.2% of women and 33.7% of men values > 250 mg/dl. Also, the following risk factors were recorded: smoking in 11.3% of women and in 20.2% of men, hypertension in 19.8% of women and 17.4% of men, diabetes mellitus in 4.2% of women and 4.1% of men, obesity in 16.8% of women and 20.9% of men, and a family history of myocardial infarction in 34.8% of women and 26.0% of men. Of the 27,084 men who had their cholesterol checked for the first time, 35.6% had levels between 201 and 250 mg/dl, and 22.9% had levels above 250 mg/dl. Of the 27,870 women whose cholesterol level had not been checked before, 38.8% had levels between 201 and 250 mg/dl, and 27.1% had levels above 250 mg/dl. More than 70% of the subjects with levels between 200 and 250 mg/dl had at least one additional risk factor. We conclude, on the basis of this study, that the risk factor hypercholesterolemia is unknown in as much as 20% of the population of Bavaria. These newly detected subjects were offered the opportunity to recognize this risk and take subsequent measures of prevention. Screening projects for hypercholesterolemia therefore can be an effective means of improving public health.

Coronary artery bypass grafting in familial hypercholesterolemia

Familial hypercholesterolemia is an autosomal dominant disorder caused by a mutation of the gene for the low-density lipoprotein receptor and is characterized by rapidly progressing coronary atherosclerosis. We assessed the long-term results of coronary artery bypass grafting performed during the past 13 years in 62 patients with heterozygous familial hypercholesterolemia, whose mean plasma total and low-density lipoprotein cholesterol level was 327 mg/dl, respectively. The patients had severe coronary atherosclerosis, with coronary stenosis index of 19.7, and the prevalence of extracoronary atherosclerotic lesions was 27%. Sixty-one patients underwent successful coronary artery bypass operation, with an average of 2.5 grafts, and the coronary stenosis index decreased to 7.1. After operation, all patients consumed a cholesterol-lowering diet and received drug therapy with pravastatin, probucol, or cholestyramine. Seven patients who were resistant to drug therapy were treated with plasma low-density lipoprotein apheresis. The cholesterol-lowering therapy reduced plasma total cholesterol level by 37%, low-density lipoprotein cholesterol level by 42%, and low-density lipoprotein/high-density lipoprotein cholesterol ratio by 37% (p < 0.001). During the follow-up period (mean, 52 months; range, 10 to 157 months), there was no cardiac death, but three patients died of malignant disease. The actuarial survival rate was 95% at 5 years and 89% at 12 years after operation. The actuarial freedom from recurrent angina was 90% at 5 years and 53% at 11 years after operation. Four patients underwent reoperation, an average of 8 years postoperatively, because of vein graft atherosclerosis. In spite of severe coronary atherosclerosis, these patients with familial hypercholesterolemia showed good long-term outcome after coronary artery bypass operation. The present findings suggest that aggressive use of arterial grafts, intensive cholesterol-lowering drug therapy, and low-density lipoprotein apheresis may be useful in patients with familial hypercholesterolemia.

Effect on plasma lipid levels of different classes of mutations in the low-density lipoprotein receptor gene in patients with familial hypercholesterolemia

We used the single-strand conformational polymorphism method to screen 311 patients with familial hypercholesterolemia from London lipid clinics and Southampton and South West Hampshire health district for mutations in the 3' part of exon 4 of the low-density lipoprotein (LDL) receptor gene. This part of the gene codes for repeat 5 of the binding domain of the LDL receptor, which is known to be critical for the receptor-mediated removal of both triglyceride-rich lipoprotein remnants and LDL. Six previously described mutations were identified in 29 apparently unrelated individuals (9.3%), with the mutations all lying within a 50-bp fragment of the gene. Three of the mutations are null alleles producing no protein, and the other three lead to production of a defective protein. The effect of the different gene mutations on lipid levels was examined, after the data were combined with information on previously reported mutations in this patient group. Mean LDL cholesterol levels were highest in those individuals with a mutation creating a null allele (9.54 mmol/L) and were similar to levels in those individuals with a mutation affecting repeat 5 that resulted in the production of a defective protein (9.37 mmol/L). In this sample, previously identified patients with a defective protein mutation outside repeat 5 had lower mean levels of LDL cholesterol (7.78 mmol/L), which were similar to levels seen in patients in whom the specific mutation had not been identified (7.31 mmol/L). Overall, these differences were highly statistically significant (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Who should treat familial hypercholesterolemia?

The treatment of various manifestations of familial hypercholesterolemia can involve a variety of health professionals over the lifetime of a given patient. The first task is to diagnose the condition. This should be done by primary physicians, i.e., pediatricians, family practitioners and internists. The same professionals, with help from dietitians as necessary, should treat the hypercholesterolemia in most cases. Homozygotes and difficult to treat heterozygotes should be referred to endocrinologists or lipidologists. The various cardiovascular manifestations, at one time or another, may require consultation with cardiologists, neurologists, radiologists, and cardiac or vascular surgeons. Physiatrists and physical and occupational therapists also may contribute to patient care.

Abdominal aortic aneurysms in familial hypercholesterolemia--case reports

Familial hypercholesterolemia (FH) is a genetic disease characterized by high serum cholesterol levels and premature coronary atherosclerosis. Hypercholesterolemia is one of the factors promoting the arteriosclerotic process and is a major cause of aortic aneurysm. Few data are available, however, about abdominal aortic aneurysms (AAAs) in patients with FH. In this study, the clinical and angiographic characteristics of AAAs found in patients with FH were investigated. Thirty-one cases (23 men, 8 women, aged fifty +/- fourteen years) were examined by coronary angiography, thoracic and abdominal aortography, and clinical data. Abdominal aortography detected abdominal aneurysms in 8 cases (26%), all of whom were men, including 4 cases (50%) that were complicated by diabetes mellitus. The abdominal aneurysm patients manifested severe coronary atherosclerosis, severe abdominal aortic irregularity, and higher blood pressure than the nonaneurysm FH patients. These findings suggest that AAAs are an important and prevalent feature in FH, especially in men with diabetes mellitus and high blood pressure.

Characteristic features of long-living patients with familial hypercholesterolemia in Japan

OBJECTIVE

To assess characteristics of long-living familial hypercholesterolemics (FHs) in comparison with younger patients.

DESIGN

Cross-sectional study.

SETTING

Lipid clinics of a university hospital and 14 related medical institutions.

PATIENTS

A total of 335 heterozygous FHs including 17 patients over 70 years old. The average ages of the aged (> or = 70 years old) and the younger groups were 73.5 +/- 3.7 and 46.5 +/- 15.0 years, respectively.

MEASUREMENTS

Medical history, serum lipids and apolipoproteins, and radiographic measurement of Achilles tendon xanthomas.

MAIN RESULTS

Age distribution of FHs suggests shorter life of FHs compared with the general population. The age distribution of FH females was shifted to older age compared with that of FH males (P < 0.01). No significant differences were found between the levels of serum lipids and apolipoproteins in the aged and the younger groups. The thickness of the Achilles tendon was positively correlated with the product of excess total serum cholesterol and age in the patients (P < 0.01). Progression of Achilles tendon thickening was less in females than in males. A few cases of longevity could not be explained by any of the anti-atherogenic factors including female gender, a relatively low concentration of serum total cholesterol, a high concentration of HLD-cholesterol, a non-smoking habit, and a familial predisposition for longevity.

CONCLUSIONS

The female gender was found to be one of the most important factors for long survival of FHs. The different progression of Achilles tendon thickening in females and males may be related to the slower development of atherosclerosis and higher survival rate of the female patients.

Risk of fatal coronary heart disease in familial hypercholesterolaemia. Scientific Steering Committee on behalf of the Simon Broome Register Group

OBJECTIVES

(a) To determine the excess mortality from all causes and from coronary heart disease in patients with familial hypercholesterolaemia; (b) to examine how useful various criteria for selective measurement of cholesterol concentration in cardiovascular screening programmes are in identifying these patients.

DESIGN

Prospective cohort study.

SETTING

Eleven hospital outpatient lipid clinics in the United Kingdom.

PATIENTS

282 men and 244 women aged 20-74 with heterozygous familial hypercholesterolaemia.

MAIN OUTCOME MEASURE

Standardised mortality ratio, all adults in England and Wales being taken as standard (standardised mortality ratio = 100 for standard population).

RESULTS

The cohort was followed up for 2234 person years during 1980-9. Fifteen of the 24 deaths were due to coronary heart disease, giving a standardised mortality ratio of 386 (95% confidence interval 210 to 639). The excess mortality from this cause was highest at age 20-39 (standardised mortality ratio 9686; 3670 to 21,800) and decreased significantly with age. The standardised mortality ratio for all causes was 183 (117 to 273) and also was highest at age 20-39 (standardised mortality ratio 902; 329 to 1950). There was no significant difference between men and women. Criteria for measurement of cholesterol concentration in cardiovascular screening programmes (family history, presence of myocardial infarction, angina, stroke, corneal arcus, xanthelasma, obesity, hypertension, diabetes, or any of these) were present in 78% of patients.

CONCLUSIONS

Familial hypercholesterolaemia is associated with a substantial excess mortality from coronary heart disease in young adults but may not be associated with a substantial excess mortality in older patients. Criteria for selective measurement of cholesterol concentration in cardiovascular screening programmes identify about three quarters of patients with the clinically overt condition.

DNA deletions in the low density lipoprotein (LDL) receptor gene in Danish families with familial hypercholesterolemia

DNA samples from 25 unrelated Danish patients with familial hypercholesterolemia (FH) were screened by Southern blot hybridization to detect gross alterations in the low density lipoprotein (LDL) receptor gene. Three FH-patients were found to have a deletion. Two of these delete part of the cysteine rich domain, which comprises the ligand binding region of the LDL-receptor. The third deletion encompasses coding regions for the cytoplasmic part of the receptor. As two of these deletions could be equivalent to previously described LDL-receptor gene alterations, these data seem to support a notion of recombination hot spots which involve Alu-sequences.

Reduction in plasma low-density lipoprotein cholesterol and urinary mevalonic acid by lovastatin in patients with heterozygous familial hypercholesterolemia

The effects of lovastatin, an inhibitor of 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMG CoA reductase), on 24-hour urinary excretion rates of mevalonic acid (an intermediate in cholesterol biosynthesis) and plasma low-density lipoprotein (LDL) cholesterol concentrations were evaluated in patients with heterozygous familial hypercholesterolemia (FH). The mean rates of urinary mevalonate excretion of 28 FH patients were initially higher (2.95 +/- 0.29 (+/- SEM) mumols/d) than in 17 control subjects (1.82 +/- 0.12 mumols/d). Patients with FH were treated with sequentially increasing doses of lovastatin (10, 20, 40, and 80 mg daily, taken as a twice daily dosage) for a period of 6 weeks on each dose. When compared to baseline, LDL cholesterol levels fell by 22%, 26%, 30%, and 35% respectively, on these different doses. The mean daily urinary mevalonate excretion decreased from baseline by 19% after 4 weeks on 10 mg daily of lovastatin, 35% on 20 mg, and 31% on 40 mg and 80 mg daily. Similar decreases in urinary mevalonate excretions were observed when patients with FH were treated directly with 40 mg (20 mg twice daily) or 80 mg (40 mg twice daily) mg of lovastatin daily. The magnitude of decrease in LDL cholesterol did not show any significant correlation with the changes in urinary excretion of mevalonic acid. Lovastatin therapy decreases rates of urinary mevalonate excretion (which has previously been shown to reflect rates of cholesterol synthesis) by up to 35% at doses of 20 to 80 mg/d; such a decrease seems unlikely to compromise other important cellular requirements for mevalonate.

Coronary artery disease and bile acid synthesis in familial hypercholesterolemia

A cohort of 97 consecutive patients (mean age 43 years), heterozygous for familial hypercholesterolemia (FH) with tendon xanthomata, were studied to explore the possible association of coronary artery disease (CAD) with classical risk factors of CAD and parameters of cholesterol metabolism, including cholesterol and bile acid synthesis. Seventy percent of the patients had CAD. Male sex, advanced age (in females), increased blood pressure (in females), obesity (in males), short stature and clinical signs of tissue deposition of cholesterol were more common in the patients with than without CAD. Serum total and LDL-cholesterol and triglyceride levels were not associated with the presence of CAD. As compared with normolipidemic healthy subjects, studied under similar conditions, the bile acid synthesis was subnormal in FH. However, the low bile acid values were associated with CAD, especially in men, while the bile acid formation was within the normal limits in the healthy FH patients. The findings suggest that FH patients with a low bile acid synthesis have an increased risk to develop coronary heart disease by an unknown mechanism.

Cardiovascular risk in patients with treated familial hypercholesterolaemia and patients with severe hypertriglyceridaemia

A study was performed to determine the morbidity and mortality from ischaemic heart disease (IHD) in patients with heterozygous familial hypercholesterolaemia (FH) and severe hypertriglyceridaemia (pretreatment plasma triglyceride greater than 5 mmol/l). Twenty-nine (38%) of 76 patients with FH and 8(44%) of 18 patients with hypertriglyceridaemia had evidence of IHD. Over a mean follow-up period of 5.5 years, 2 patients with hypertriglyceridaemia died but there were no deaths in patients with FH. This contrasts with earlier reports which showed a high mortality in FH patients. The lower mortality may be due to improved treatment and consequent lower levels of cholesterol.

Causes of death in patients with familial hypercholesterolemia

Five out of 15 homozygotes and 41 out of 527 heterozygotes of familial hypercholesterolemia (FH) died during the past 10 years. Sudden death or heart failure was the cause of death in each of the 5 deceased homozygotes. Twenty heterozygotes died of myocardial infarction, 9 of sudden death, and 1 died after AC bypass surgery. Thus, 30 heterozygotes (73.2%) died of coronary heart disease (CHD). The mean age of death was significantly younger in male heterozygotes (54 years) than in the females (68 years). Rate of death from CHD in heterozygotes was 11 times higher than in the general population in Japan. Rate of death from pancreas cancer in FH was significantly higher than in the general population. These results suggest that FH is highly associated with pancreas cancer as well as CHD.

Fenofibrate and colestipol: effects on serum and lipoprotein lipids and apolipoproteins in familial hypercholesterolaemia

Effects on serum lipoproteins were studied in ten patients with familial hypercholesterolaemia (FH) during consecutive eight-week treatment periods with fenofibrate 0.3 g/day, fenofibrate plus colestipol, 15 g/day, and fenofibrate 0.25 g/day plus colestipol. VLDL, LDL, HDL, HDL2, and HDL3 were isolated by ultracentrifugation and precipitation. Lipids and apolipoproteins A-I and B were determined by enzymatic and immunonephelometric techniques, respectively. Administration of fenofibrate alone resulted in decreases in VLDL and LDL cholesterol (-48% and -18%) and in serum apolipoprotein B (-10%), but in increases in HDL, HDL2, and HDL3 (+25%, +26%, and +24%), and in serum apolipoprotein A-I (+6%). Addition of colestipol produced a further reduction in LDL cholesterol (-31%) and in serum apolipoprotein B (-19%). The effects were maintained with less fenofibrate. In FH, an acceptable therapy combines the favourable effects of sufficient lowering of LDL and of a rise in HDL.

Hypocholesterolemic effects of mevinolin in patients with heterozygous familial hypercholesterolemia

We have evaluated the hypolipidemic effects of mevinolin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme in cholesterol biosynthesis in 13 patients with heterozygous familial hypercholesterolemia (FH). Patients were maintained on a low-cholesterol diet and received sequentially increasing doses of 5, 10, 20, and 40 mg of mevinolin twice daily for a period of 1 mo on each dose. Plasma concentrations of low density lipoprotein cholesterol decreased by 19.8% on the 5 mg twice daily dose (P less than 0.05 vs. base line), 28.4% on 10 mg of mevinolin twice daily (P less than 0.05 vs. 5 mg twice daily), 35% on 20 mg of mevinolin twice daily (P less than 0.05 vs. 10 mg twice daily), and 37.7% on 40 mg of mevinolin twice daily (not statistically different from 20 mg twice daily). Concentrations of high density lipoprotein cholesterol remained stable on all doses of mevinolin whereas plasma triglyceride levels fell significantly on the 20 mg (-30.7%) and 40 mg (-34.3%) twice daily doses of mevinolin. Mevinolin was well tolerated and all patients completed the study period. Side effects during the period of study were limited to transient insomnia and headaches in two patients, transient increases in alkaline phosphatase in three patients, and a modest but sustained increase in alkaline phosphatase in a fourth patient. These results indicate that mevinolin is an effective hypolipidemic agent in patients with heterozygous FH but that the optimal doses in these patients are greater than those previously reported in normal volunteers. If long-term safety can be satisfactorily established, mevinolin offers considerable promise in the therapy of heterozygous FH.

Treatment of hypercholesterolemia

After discussing the indications for treatment of familial hypercholesterolemia and the importance of a differential diagnosis, the authors describe drug therapy for the disorder with special attention to combined drug regimens. The surgical treatment of hypercholesterolemia and the treatment of homozygous and other forms of hypercholesterolemia are also detailed.

Familial type II hyperlipoproteinemia with coronary heart disease: effect of diet-colestipol-nicotinic acid treatment

Heterozygous familial type II hyperlipoproteinemia (F type II) is primarily manifested in hypercholesterolemia (due to low density lipoprotein-cholesterol [LDL-C] elevation) and premature coronary heart disease (CHD). We studied sequentially the effects of low cholesterol-low saturated fat-low simple carbohydrate diet; diet and colestipol, 30 g/day; and diet, colestipol, plus nicotinic acid (NA) 3 to 7 g/day on plasma cholesterol (Ch), LDL-C, triglyceride (TG), high density lipoprotein-cholesterol (HDL-C) and angiographically documented coronary arterial lesions of 32 F type II patients. Effective control of F type II resulted in arresting the progression of angiographically demonstrated coronary arterial lesions.

Normalization of low-density-lipoprotein levels in heterozygous familial hypercholesterolemia with a combined drug regimen

We studied the effect of th bite acid sequestrant colestipol, alone and in combination with clofibrate or niacin, in patients with heterozygous familial hypercholesterolemia who were given a diet low in cholesterol and saturated fat. With colestipol alone, mean cholesterol levels in serum decreased 16 to 25 per cent. The addition of clofibrate produced a total mean decrement of only 28 per cent. In contrast, serum cholesterol levels fell 45 per cent when colestipol as combined with niacin. Low-density-lipoprotein (LDL) cholesterol decreased 55 per cent with colestipol and niacin, whereas high-density-lipoprotein (HDL) cholesterol increased. Mean LDL cholesterol was lower in patients given this regimen than in matched normal controls eating an unrestricted diet. Tendinous xanthomas, measured by quantitative xeroradiography, were significantly reduced (P < 0.01), indicating that this regimen mobilized cholesterol from tissue pools with slow turnover. Colestipol plus niacin promises to be useful in the treatment of patients at high risk from elevated levels of LDL.

Achilles tendon thickness and ischemic heart disease in familial hypercholesterolemia

Achilles tendon thickness (ATT) of 112 patients with familial hypercholesterolemia (FH) with and without ischemic heart disease (IHD) was measured radiographically and was compared with that of normal subjects. The mean and SD of serum cholesterol in the heterozygotes (107 cases), the homozygotes (5 cases) and the normal subjects (36 cases) were 347 +/- 63, 589 +/- 69 and 187 +/- 30 mg/dl, respectively. The mean and SEM of ATT in the heterozygotes, the homozygotes and the normal subjects were 12.5 +/- 0.4 mm, 18.6 +/- 6.6 mm, and 6.3 +/- 0.2 mm, respectively. Cutaneous xanthomas were observed in 34 out of 112 patients (30.4%). Increased ATT was observed in 95 (84.8%). IHD was diagnosed in 39 (34.8%). The ATT of FH with IHD was significantly thicker than that of FH without IHD (P less than 0.05) and that of normal subjects (p less than 0.001). Thus, the increased ATT evaluated by x-ray was the earliest clinical sign of FH and the measurement of ATT seems to be a useful adjunctive procedure for detecting familial hypercholesterolemic patients and predicting IHD in them.

Evaluation of an automated immunoassay procedure for apo-LDL for phenotyping type II hyperlipoproteinemia

Apo-low density lipoproteins were determined by an automated immunoassay procedure on serum samples from 88 normolipidemic individuals and 84 hyperlipoproteinemic subjects, to establish whether this method was useful in the routine detection of type II hyperlipoproteinemia. The results obtained were compared with the cholesterol levels of the same specimens. In subjects with type II hyperlipoproteinemia, the apo low density lipoprotein levels, as well as the ratio of low density lipoprotein cholesterol/apo-low density lipoprotein were higher, as expected, than in normals or in subjects with other types of hyperlipoproteinemia. However, there was considerable overlap in individual values of both these parameters, between patients with type II hyperlipoproteinemia and normals or subjects with other types of hyperlipoproteinemia, suggesting that apo low density lipoprotein levels alone were not sufficiently discriminatory for the laboratory determination of type II hyperlipoproteinemia.

Family similarities in the age at coronary death in familial hypercholesterolaemia

In a combined Norwegian and British study of the age at death from coronary heart disease of heterozygotes for familial hypercholesterolaemia (FH) the correlation coefficients within families for 43 sib pairs was 0-70 and for 14 first cousin pairs 0-61. There was no significant correlation between the age at death and serum cholesterol concentration in either series. The intrafamilial correlations suggest that information about the age at death from coronary heart disease in heterozygotes within families may have some prognostic value and may also be interpreted as evidence for genetic heterogeneity in FH.