High cholesterol and cardiac risk
Hyperlipidemia is a medical problem in which there are high levels of lipids (fats) in the blood. This can increase one’s risk of heart disease, brain stroke, and limb ischemia. These conditions happen when the blood vessels in these different organs get clogged with fatty deposits, restricting blood flow and leading to organ damage.
There are several types of hyperlipidemia:
This type is characterised by high levels of cholesterol in the blood. While total cholesterol has been the primary focus, most current guidelines focus on low-density lipoprotein-type cholesterol, as high LDL levels are associated with the greatest risk of cardiovascular diseases and death. In general:
● A total cholesterol level of less than 200 mg/dL is normal.
● A total cholesterol level of 200 to 240 mg/dL is borderline high.
● A total cholesterol level of greater than 240 mg/dL is high.
Total cholesterol level and LDL can be measured any time of day. It is not necessary to fast before testing.
It is characterised by high levels of triglycerides in the blood.
Where there are high levels of both cholesterol and triglycerides.
Lipid levels can almost always be lowered with a combination of diet, weight loss and medications. There are several types of drugs that can be used to treat hyperlipidemia. The mostly-used ones include:
They work by blocking an enzyme in the liver that is involved in the production of cholesterol. Statins are one of the best-studied classes of anti-lipid agents and the most effective drugs for cardiovascular risk prevention, as they reduce LDL-cholesterol levels by as much as 50 per cent. In addition, they can lower triglycerides. Statins may also reduce inflammation, preventing heart attacks and strokes through this mechanism. Since their inception, statins have saved millions of lives across the globe.
While most people tolerate statins well, there are some potential side effects, mainly muscle aches. In addition, and in those with prediabetes, statins may slightly increase the risk of developing overt diabetes. However, the cardiovascular protection benefit is several fold higher than that of diabetes risk.
It blocks the body's ability to actively transport cholesterol from food and inside the body systems. It lowers LDL levels by 20 per cent and has relatively few side effects. It is usually prescribed in combination with a statin, but can be used alone in patients intolerant to statins.
They are a new class of drugs that can deeply lower LDL levels. They are given by injection every two to four weeks. They have a few side effects but are quite expensive, and their use is limited to patients treated with maximal tolerated statins and ezetimibe, who have persistently elevated LDLs.
Bile acid sequestrants
These medications work by binding to bile acids in the intestine, which helps to lower cholesterol levels in the blood.
They work by increasing the breakdown of triglycerides in the liver.
Oily fish, such as mackerel, sardines, and salmon contain two beneficial omega-3 acids called docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Eating a diet that includes two servings of oily fish per week can lower triglyceride levels and reduce the risk of death from coronary heart disease.
Fish oil supplements, that have usually 1 gram per day of combined DHA and EPA, had been thought to provide cardiac benefit, but large trials have found no such advantage. With that, they are no longer recommended. On the other hand, pharmacological preparations with more refined omega-3 acids at much higher doses have been found to reduce cardiovascular risk, but mainly when combined with a statin.
It is worth mentioning that omega-3 acids have been found in some studies to slightly increase the risk of an irregular heart rhythm called atrial fibrillation.
When is a treatment for high lipids needed?
In people with established cardiovascular disease
Many studies have shown the significant benefit of treating everyone with known CVD, with a high-dose statin therapy. After starting a statin, LDL level is rechecked; a second medication may be suggested if the level remains higher than 70 mg/dl. In fact, clinical trials have found that if the LDL-cholesterol is reduced to less than 70 mg/dL and preferably less than 50 mg/dL, the size of fat plaques in the vessels can get slightly smaller. More importantly, these plaques can become stable, ie may not increase in size, or rupture causing a stroke or a heart attack.
In people without CVD
They also benefit from cholesterol-lowering therapy, although the goal is generally not as aggressive as in people with CVD. The decision of whether to start such a treatment is based on one’s individual risk for developing heart disease. Calculators are available to estimate this risk based on age, sex and medical history. Sometimes a coronary calcium score test is done to see if a cholesterol build-up is already present in the heart arteries; if so, then statin treatment is recommended.
People with high triglyceride levels
Diet and exercise are usually quite effective in lowering triglycerides. The dietary interventions include low carbohydrates diet, restricted calories, and no alcohol. However, patients with very high triglyceride levels (above 800-1000 mg/dL) may be started on treatments to lower the risk of pancreatitis (inflammation of the pancreas, a serious condition). In this instance, a statin combined with fibrates [mentioned above] are usually the first line of treatment.
People with diabetes
People with diabetes are at high risk of heart disease. A moderate- or high-intensity statin is recommended in most adults with diabetes, regardless of their baseline LDL cholesterol level.
When should hyperlipidemia screening start?
An initial screening profile is often pursued during childhood, and should be repeated again at 18 years of age. For adult men, a regular lipid check should start at age 35 years if there are no known cardiovascular disease risk factors. Screening should start 10 years earlier if the patient has obesity, diabetes, high blood pressure, smoking, or a family history of premature cardiac disease. Same applies to women, but with a ten-year lag known as “gender gap”.
Afterwards, a reasonable approach would be to repeat lipid screening every three to five years, as long as the patient is not yet on therapy. More frequent checks are needed once a drug is started.
A word on nutritional supplements
They contain isoflavones that can slightly lower total cholesterol, LDL, and triglycerides. However, because isoflavones imitate oestrogen in the body, normal dietary proteins should not be replaced with soy proteins in an effort to lower lipids.
Plant sterols may act by blocking the absorption of cholesterol in the intestine. Despite lowering cholesterol levels, there are no studies demonstrating a reduced cardiac risk in persons who consume the above nutritional supplements, and hence they are not recommended as statins replacements. Other supplements are fads and do not reduce lipids and/or cardiovascular risk.
The information herein is not intended as medical advice nor as a substitute for professional medical opinion. Always seek the advice of your physician. You should never delay seeking medical advice, disregard medical advice or discontinue treatment because of any information in this article.