THE CHOLESTEROL SCREENING - MEDICAL POINT OF VIEW
Previous chapiter: The cholesterol
You have just seen your doctor and he recommends a blood test to find out your lipid profile. Do you know exactly what he is looking for?
He is looking to see if you have excess cholesterol in your blood so he can better assess your cardiovascular risk.
Cardiovascular risk becomes higher with age, if you are a man, and family history of early cardiovascular disease (heredity). It is also influenced by certain risk factors that can be modified, for example ;
• Type 2 diabetes,
• Physical inactivity,
• The cholesterol concentration in the circulation.
A dyslipidemia is an abnormality in the level of lipids, or in other words, the fat in the body.
Screening for dyslipidemia, for whom and when?
Evaluating the risks of the cardiovascular disease and the determination of lipids should be considered;
• In individuals over 40,
• In individuals at increased risk, regardless of their age.
The following conditions are associated with an increased risk of cardiovascular disease:
• Documented atherosclerosis, or cholesterol plaques in the arteries
• Aneurysm of the abdominal aorta (abdominal hemorrhage)
• High blood pressure
• Appearance of dyslipidemia on the skin or in the eyes (corneal arches, xanthelasms or xanthomas
• Family history of premature cardiovascular disease (<55 years for men, <65 years for women)
• Family history of dyslipidemia
• Chronic kidney disease
• Obesity (BMI ³ 30 kg / m2)
• Inflammatory bowel disease
• HIV infection
• Erectile dysfunction
• Chronic Obstructive Pulmonary Disease (COPD)
• Hypertensive diseases during pregnancy (preeclampsia)
Cholesterol comes from two sources: from our diet and from our own body’s production controlled by a genetic thermostat.
The liver, intestines and skin produce the cholesterol needed to build the cell membranes (the skin that surrounds the cells), the production of sex hormones, vitamin D and bile acids that help digest fats.
Cholesterol is transported throughout the body by lipoproteins that act as taxis for the fat.
Bad and good cholesterol
We find two types of cholesterol in the blood. The first one is low-density lipoprotein cholesterol (LDL-C), also called "bad cholesterol" since it is deposited in the arteries, especially those of the heart (arteries coronary). This reduces their effectiveness because atheroma plaques are formed, the make the passage of blood is more more difficult and clots form which may lead to thrombosis ).
Second, we find the cholesterol carried by the high density lipoprotein (HDL-C), which is called the "good" cholesterol since this cholesterol is collected throughout the human body and returns to the liver to be eliminated through bile salts or more commonly called bile.
High HDL-C levels and low LDL-C levels significantly reduce the risk of clogged arteries and heart attack.
What we are looking for in a screening test
During a screening test for dyslipidemia, your doctor will mainly look for levels of cholesterol in your blood, triglycerides (fat), and specifically the LDL-C and HDL-C levels. These tests refer to the standard lipid profile.
This profile, much like a picture of the fats in your blood, will inform your doctor about your lipid levels. These levels are usually read in mmol / Liter.
Should we be fasting?
Until recently, these tests required fasting for 12 hours. The most recent Canadian recommendations now state that it is acceptable to have the blood test for information on lipids without fasting.
It is possible that a cholesterol test be repeated while fasting for 12 hours if the current test shows a high level of triglycerides (> 4.5 mmol / L). Triglycerides are another type of fat. A high result of this type of fat can falsify the results of good and bad cholesterol.
How to detect
We can detect dyslipidemia by the presence of cholesterol accumulation on the skin, on the eyelids, in the eyes or with a blood test.
Who should be treated?
If you are in good cardiovascular health and have no other risk factors, treatment is not necessary when your LDL-C levels are very low (less than 5 mmol / L).
If you have certain risk factors and your doctor estimates that you have a risk of intermediate or high cardiovascular disease, he or she will start statin therapy to lower your LDL-C to less than 2 mmol / L or at least bring you to half your initial LDL-C.1
But before treating
Medication is rarely started after the first screening. The follow-up that will be done by your doctor depends mainly on your personal history of cardiovascular disease and the presence of risk factors.
The very first thing to do will be to review your lifestyle habits to reduce your risk of cardiovascular disease. For example, stop smoking, attain a healthy weight, lead an active lifestyle and reduce stress. In other words, adopt healthy lifestyle habits.
Do not forget that our diet is one of two sources of blood cholesterol level.
Medical practice attempts to modify lifestyles harmful to health and a control test is done after a few months.
It is possible that medication is necessary to lower your LDL-C levels. Your doctor may prescribe a statin.
This drug is now recognized as the best medication to lower blood cholesterol levels and minimize the risk of atherosclerotic heart disease.
How does statin therapy work
Statins act in the liver by blocking the enzyme responsible for producing cholesterol.
By decreasing circulating cholesterol, less plaque builds up on the artery walls, arteries do not narrow as much and the possibility of blood clots causing a heart attack or stroke are reduced.
Thus, this therapy reduces LDL-C and total cholesterol. Il also lowers triglycerides and increases HDL-C levels.
It can also help stabilize plaques in the arteries and decrease the risk of heart failure making them less likely to crack.
A therapy with a major impact on life
Taking statins significantly reduces the mortality rate in people with high cardiovascular risk.
In fact, studies have shown that taking statin reduces the risk of reliving a major vascular event, heart attack or stroke by 25% for each 1 mmol / L reduction in LDL-C for each subsequent year.2
Several kinds of statins
Your doctor will choose the right statin and start treatment with the lowest effective dose.
The most common side effects to watch out for
The known side effects of statins are mainly muscle pain (myalgia). These pains are always present. It is as if the muscle had made a great effort.
In fact, all medications in the statins category are associated with muscle disorders.
Moreover, in approximately 1% of patients, the liver seems to function less effectively with statin intake.
Some statin drugs are potentially diabetogenic with a higher risk for higher doses.
It is possible to check all these side effects with blood tests.
Finally, statins have certain interactions with other medication like most pills.
It has been shown that most of the side effects that cause symptoms attributed to statin therapy in current practice are not really caused by this treatment implying that they are falsely reported.
It is of concern to note that some patients discontinue the use of their statin because of these exaggerated reports on side effects, especially patients at increased risk for cardiovascular events.
As mentioned, there are several types of statins, and all major brands are now available in generic forms.3 The major pharmaceutical industries receive more revenue from these sales.
An informed decision is necessary
The decision to take a statin and to choose one type over another should be taken in collaboration with your doctor, after one or more discussions about your medical and personal concerns. The discussions should also be based on facts from broad scientific studies done around the world over many years.
When a patient does not reach a sufficiently low level of LDL-C with statin therapy, the health care professional may prescribe additional treatment: ezetimibe 10 mg / day.
Ezetimibe is recommended by Canadian specialists for dyslipidemia in addition to the already prescribed medication.1
This drug acts in the intestine to reduce the reabsorption of cholesterol by the body favoring its elimination, promoting a further decrease in LDL-C in the blood of up to 25%.
Bile acids chelators
Other medicines called chelating resins of bile acids also act in the intestine; a rather complicated name that simply means that they prevent bile salts from being reabsorbed normally by the intestine to return to the gall bladder.
This exaggerated loss of bile salts must be replaced. To be made, they require cholesterol and they get it from the blood, obviously reducing cholesterol levels in the blood. This type of medication can be added to the therapy against hypercholesterolemia.
A new addition: the inhibitor of PCSK9
The preferred additional statin treatment after adding ezetimibe is the use of an inhibitor of PCSK9, a new class of medications.
The evolocumab and alirocumab have recently been accepted in Canada and have demonstrated an ability to reduce LDL-C by 50 to 70% in patients with and without statins.
These new drugs are currently prescribed to patients with known cardiovascular disease who do not achieve low levels of LDL-C despite taking statin and / or ezetimibe, or to patients with genetic hypercholesterolemia (known genetic cause of elevated levels of LDL-C).
A control for cholesterol in blood with the therapy to be done
The lipid profile should be repeated about 3 months after the start of the treatment.
Subsequently, a regular follow-up for the LDL-C will be necessary in order to check if the results reach the target level. If this is the case, the lipid balance will have to be repeated 1 to 2 times per year in order to verify if the levels of LDL-C are maintained. However, in the opposite case, the treatment must be modified.
So in summary:
• A blood test is done to determine the amount of cholesterol in your blood.
• If your LDL cholesterol level is high, your risk of heart disease increases, especially when other factors increase your risk.
• Depending on your overall risk, your doctor may recommend lipid-lowering therapy with statins to lower your cholesterol.
• If necessary, he will use ezetimibe and PCSK9 inhibitors for further LDL-C reduction.