Familial Hypercholesterolemia Treatment & Management

The National Cholesterol Education Program (NCEP) ATPIII defined LDLc goals and cutpoints for therapeutic intervention based on risk for CHD (see Table 2 and Table 3).^{[16, 17]}

The guidelines were updated in 2004 to reflect the findings of several interventional trials demonstrating that coronary event rate was reduced after lowering the LDLc well below 100 mg/dL.^[18]

The European Society of Cardiology (ESC) and European Atherosclerosis Society (EAS) have also released guidelines for the management of dyslipidemias, available at the ESC site.^[19]

CHD or CHD risk equivalent

• Clinical CHD
• Symptomatic carotid artery disease or carotid stenosis greater than 70%
• Peripheral artery disease
• Abdominal aortic aneurysm
• Diabetes
• Global 10-year risk of major CHD event (ie, fatal or nonfatal myocardial infarction) greater than 20%

Determination of risk

Treatment of elevated LDLc levels is based upon the risk for a coronary heart disease (CHD) event (see Table 1). The 2001 National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATPIII) defined target LDLc levels and levels based on risk for CHD.^[16] The 2004 update added optional lower LDLc goals to reflect the findings of several interventional trials demonstrating that more aggressive LDLc lowering further reduced coronary event rate.^[18]

In patients without atherosclerotic disease, the risk for developing CHD is defined by the number of major risk factors for CHD and by the following:

• Hypertension (blood pressure ≥140/90 mm Hg or treatment for hypertension)
• Cigarette smoking (any within the past mo)
• HDLc level below 40 mg/dL
• Male sex and age 45 years or older
• Female sex and age 55 years or older
• Family history of premature CHD: Clinical CHD or sudden death in first-degree male relative younger than 55 years or first-degree female relative younger than 65 years

An HDLc level of 60 mg/dL or greater is a negative risk factor for CHD and its presence removes one risk factor from the total.

Percent risk for developing CHD or having a major CHD event (ie, fatal or nonfatal myocardial infarction) is determined by calculating the Framingham risk score, which is available through the US National Heart, Lung, and Blood Institute (see Risk Assessment Tool for Estimating 10-Year Risk of Developing Hard CHD).

• LDLc goal less than 100 mg/dL
• Therapeutic lifestyle changes (TLC) instituted at LDL 100 mg/dL or more
• Medical therapy initiated at LDL 100 mg/dL or more (new 2004 cut off point)

Optional LDLc goal less than 70 mg/dL, especially for very high risk patients include the following:

• Patients with CHD and multiple other major risk factors for CHD, especially diabetes
• Severe, poorly controlled risk factors, especially continued cigarette smoking
• Multiple risk factors of the metabolic syndrome
• Patients admitted with an acute coronary syndrome

Moderately high risk, more than 2 risk factors

• See Table 2
• Global risk 10-20% - LDLc goal less than 130 mg/dL, optional LDLc goal less than 100 mg/dL
• Consider medical therapy for LDL 100-129

Moderate risk, 2 risk factors or more

• Global risk less than 10% - LDLc goal less than 130 mg/dL

Low risk

• None to 1 major risk factor for CHD
• LDLc goal less than 160 mg/dL
• Low-risk patients have fewer than 2 risk factors and a 10-year risk for a major CHD event that is almost always less than 10%. The goal LDLc is less than 160 mg/dL.
• Moderate risk patients have 2 or more factors and a 10-year risk for CHD of less than 10%. The goal LDLc is less than 130 mg/dL.
• Moderately high risk patients have 2 or more risk factors and a 10-year risk of 10-20%. The goal LDLc is less than 130 mg/dL and the update suggested an optional goal LDLc of less than 100 mg/dL.

The highest category of risk includes CHD and CHD risk equivalents include the following:

• Clinical CHD
• Symptomatic carotid artery disease (transient ischemic attack or stroke of carotid origin)
• Peripheral artery disease
• Abdominal aortic aneurysm
• Diabetes
• 10-year risk less than 20%

The LDLc goal for high-risk patients is less than 100 mg/dL and the 10-year risk is greater than 20%. In addition to lifestyle changes, institution of medication is recommended if LDLc level is greater than 100 mg/dL. Patients at high or very high risk have an optional LDLc goal of less than 70 mg/dL.

Patients with cardiovascular disease who are at very high risk have an optional LDLc goal of less than 70 mg/dL.

Very high risk is defined as the presence of the following:

• Multiple other major risk factors for CHD, especially diabetes
• Severe, poorly controlled risk factors, especially continued cigarette smoking
• Multiple risk factors for the metabolic syndrome (especially triglycerides >200 mg/dL, non-HDLc >130 mg/dL, and HDLc < 40 mg/dL)
• Patients with acute coronary syndromes

Table 1. LDLc Target levels and levels Indicating Therapeutic Lifestyle Changes (TLC) and Drug Therapy (Open Table in a new window)

Because of improved diet normally results in upregulation of LDL receptors, the impact of diet changes on LDLc levels in homozygous patients is negligible (there are no receptors to upregulate), but lifestyle changes have other cardiovascular benefits and should be strongly encouraged.^{[20, 21]}

Because of the severity of CHD and lack of response, homozygous FH patients require heroic intervention.

Occasionally, the LDL receptors retain some degree of function and diet control and high doses of HMG-CoA reductase inhibitors combined with bile acid sequestrants, ezetimibe, and niacin can be effective.^[22] Estrogen replacement therapy in postmenopausal women is also effective, but this therapy is not recommended because of its adverse effects in older women. However, in some women the benefits may outweigh risks.

When the LDL receptors are absent or nonfunctional, one of the following is necessary:

LDL apheresis for homozygous FH involves selective removal of lipoproteins that contain apo-B by heparin precipitation, dextran sulfate cellulose columns, or immunoadsorption columns. All methods reduce LDLc levels more than 50% and also lower lipoprotein (a), VLDL, and triglyceride levels. HDL is spared. The procedure takes 3 or more hours and is performed at 1- to 2-week intervals. Few adverse events are experienced, most of which are noncritical episodes of hypotension. LDL apheresis is an extremely expensive procedure and is not readily available.^{[23, 24]}

Portacaval anastomosis

Compared to liver transplantation (see Surgical Care), this procedure is less hazardous and requires no immunosuppression.

Although cholesterol levels are not reduced as dramatically when compared with transplantation or apheresis, the clinical benefits appear comparable.

LDLc reductions 50% have been reported; regression of coronary lesions, aortic lesions, and xanthomas have been documented.

The exact mechanism by which LDLc is lowered is unclear.

Other treatments for homozygous FH

Probucol, a medication with only mild LDL-lowering effects and an undesirable HDL-lowering impact, has been shown to cause regression of cutaneous and tendon xanthomas in patients with both homozygous and heterozygous FH. An animal model has demonstrated reduced coronary atherosclerosis. No long-term benefits have been documented for patients with FH.

Gene therapy is still at the investigational stage. Initially, expectations were high that genetic manipulation would be a less hazardous method for providing functional LDL receptors compared with liver transplantation; however, advances have been slow.

In patients with heterozygous FH, lifestyle modification should always be instituted but is unlikely to result in acceptable LDLc levels; therefore, cholesterol-lowering medication (usually more than one) is necessary.^[21]

A diet that severely limits saturated fats, trans fats, and cholesterol (see Table 2)^[20]

Desirable weight should be attained. Significant weight loss should improve all lipid parameters (LDLc, HDLc, triglycerides).

Aerobic and toning exercises improve blood lipid levels if performed for longer than 30 minutes, 4 or more days per week.

While these efforts often have only a modest impact on LDLc levels, rigorous dietary intervention works synergistically with lipid-lowering medications, especially diet.^[20]

With 50% functional LDL receptors, heterozygous FH patients have an excellent response to the usual cholesterol-lowering drugs, but treatment still remains difficult.

To approach the recommended LDLc goals, a high dose of one of the 3 strongest HMG-CoA reductase inhibitors (statins), simvastatin, atorvastatin, or rosuvastatin, and one or more other LDL lowering medications, bile acid sequestrants, ezetimibe, or niacin, is recommended.^[22] To decrease the risk of myopathy, one step below the maximum dose of the statin should be considered. For additional resources, please visit Landmark Statin Trials.

Because doubling the dose of any statin lowers the LDLc only 6-7%, adding a second, third, or even fourth agent is more effective.^[25]

A pooled analysis of 5 statin trials revealed that intensive-dose therapy was associated with a greater risk of diabetes when compared with moderate dosing.^[26]

Fibrates have no place in treatment of patients with FH unless triglyceride levels are elevated.

Estrogen replacement therapy in postmenopausal women also helps lower LDLc levels, but this therapy is not recommended because of its adverse effects in older women, although the benefits may sometimes outweigh risks.

Patients with documented CHD whose LDLc level cannot be lowered below 200 mg/dL by conventional therapy are candidates for LDL apheresis. Patients without CHD but with an LDLc level of higher than 300 mg/dL also qualify for this intervention. However, health insurance coverage is not automatic, and decisions are made on a case-by-case basis because of the costs, which approach $3000 for each treatment, every 2 weeks, for the patient's lifetime.

Liver transplantation for homozygous FH

Liver transplantation is rarely performed because of the considerable risks associated with the surgery itself and long-term immunosuppression. But a new liver provides functional LDL receptors and causes dramatic decreases in LDLc levels.

If not normalized, LDLc levels then can be treated with the usual LDL-lowering medications.

Portacaval anastomosis for homozygous FH

This may be indicated.

Homozygous FH

Because the risk of sudden death or nonfatal myocardial infarction is so high, early or highly specialized treatment is necessary.

As soon as a child is diagnosed with homozygous FH, a referral should be made to a medical center specializing in severe lipid disorders.

Referral to center providing LDL apheresis

Heterozygous FH

Refer to qualified nutritionist to provide guidance in reducing intake of saturated and trans fats and cholesterol and assist in weight reduction if indicated.

If patients do not reach recommended treatment goals under the care of their primary care physicians, they should be referred to an endocrinologist or lipid specialist and to a qualified nutritionist.

If patients are considered candidates for LDL apheresis and are willing to undertake this arduous procedure, referral should be made to a medical facility offering this procedure.

Predicting the degree of improvement in an individual's lipids levels with dietary change is difficult because many variables affect the response, including the makeup of the baseline diet, the degree of patient compliance, and the individual's LDL responsiveness to the diet, which is genetically determined. A decrease of at least 15% can be expected in heterozygous patients who are willing to make significant dietary changes.

The 2001 NCEP ATPIII guidelines emphasize a multifaceted approach to the prevention of CHD.^[16] Designated therapeutic lifestyle changes (TLC), its features include increased physical activity, weight reduction, and diet modification. The same diet is recommended for all patients with lipid abnormalities.

The NCEP recommendations for the dietary management of hypercholesterolemia are not highly restrictive, but a more stringent regimen may have a greater impact on lipid levels (see Table 2).

Restricting total fat is less important than reducing the intake of saturated fat, trans fat, and cholesterol. Moreover, diets very low in total fat are high in carbohydrates, which may increase triglyceride levels and lower HDLc levels. Substituting monounsaturated fats (eg, olive and canola oils, avocados, nuts) for carbohydrates does not increase LDLc levels and, in the absence of weight gain, may increase HDLc levels and lower triglyceride levels in patients who have maintained a diet very low in fat.

Diets should be rich in whole grains, whole fruit, and legumes and other vegetables. These foods are high in soluble fiber, which has a small (approximately 5%) cholesterol-lowering effect; they are also high in antioxidants and flavonoids, which may be cardioprotective.

Table 2. Recommended Dietary Intake (Open Table in a new window)

Other features of the NCEP diet are as follows:

• Fiber (soluble fiber): Intake should be 20-30 g/d.
• Carbohydrates: Intake should be 50-60% of total energy (caloric) intake. Carbohydrates should be derived predominantly from foods rich in complex carbohydrates, including grains, especially whole grains, fruits, and vegetables.
• Plant sterols and stanols: Intake should be 2 g/d.^[15] These are present in commercial margarines (eg, Benacol, Take Control).
• Total energy (caloric) intake: Balance energy intake and expenditure to maintain desirable body weight and prevent weight gain. Daily energy expenditure should include at least moderate physical activity, contributing approximately 200 Kcal/d (eg, a brisk walk of 2 miles or more).
• Trans- fatty acids (trans fats): Intake should be avoided. Products made with hydrogenated fats contain variable amounts of trans fats. Similar to saturated fats, trans fats increase LDLc levels. However, unlike saturated fats, trans fats decrease HDLc levels. Hydrogenated fats and trans fats are found in many margarines, cakes, cookies, crackers, and frosting.

Exercise has many cardiovascular benefits and can improve blood lipid levels. Although a greater proportion of time should be spent doing aerobic exercise because of its greater impact on lowering blood pressure and decreasing insulin resistance, resistance training also has benefits.

Patients with CAD or symptoms suggestive of ischemic heart disease should undergo a symptom-limited exercise stress test before undertaking a new program of vigorous exercise.