Primary Stroke Prevention

For the most part, this consists of interventions aimed at controlling risk factors for stroke. We can break this down further into a number of categories.  

1. Atherogenic (blood vessel) factors
2. Cardiac abnormalities
3. Other factors.

 

Some of the risk factors for stroke are alterable (such as high blood pressure, diabetes) and some are not (family history, prior history of stroke, age, and sex). 

Atherogenic Factors: Strokes, whether ischemic (non-bleeding, approximately 80%) or hemorrhagic (bleeding, approximately 20%), occur when blood supply to the brain is altered, leading to the death of some of the neurons (nerve cells) in the brain. This is analogous to what happens to heart muscle after a heart attack. There are many risk factors that affect the integrity of blood vessels. Controlling them is one of the most important keys to stroke prevention.  

The blood vessels that supply the brain are damaged by many factors including hypertension (high blood pressure), abnormalities of lipid metabolism (commonly known as, but not limited to high cholesterol), diabetes mellitus, obesity, elevated homocysteine levels, hypercoagulable state (having abnormally “thick” blood).  

Hypertension: Hypertension or high blood pressure is probably the most common disorder that affects the cerebrovascular system (blood supply to the brain). Our blood pressure is, in general, measured by two numbers, systolic blood pressure (the top number) and diastolic blood pressure (the bottom number). The systolic blood pressure is the pressure in your arteries when your heart is beating. The diastolic blood pressure is the pressure in your arteries when your heart is at rest. If somebody’s blood pressure is 140/90, the systolic blood pressure is 140 and the diastolic blood pressure is 90.  

As issues in medicine go, control of blood pressure, in most cases, can easily be accomplished with administration of medication. Of course, lifestyle changes (diet, exercise, decrease in alcohol intake, weight loss, etc.) are the first steps to controlling blood pressure. If these are not successful, we currently have multiple classes of blood pressure medications and dozens of medications in each class. There are certain classes of these medications that have more literature in the stroke population; however, there are many other factors that should go into the decision of which blood pressure medication is appropriate for any particular person. This should be discussed with your primary medical physician or the doctor who was taking care of your high blood pressure. It is clear, however, that no matter which medication one uses, if the blood pressure is reduced, it is beneficial to stroke prevention. This applies to reduction of both the systolic and diastolic blood pressures.  

One caveat is that two related classes of blood pressure medications (the ACE inhibitors and angiotensin receptor blockers [ARB]), at least at this point, seem to confer an additional measure of protection against stroke above and beyond their effect on blood pressure. It is, for this reason, that all other things being equal, these medications should likely be the blood pressure-lower medication of choice for stroke prevention.  

Abnormalities of Lipid Metabolism (better known as high cholesterol): Your body has different types of cholesterol. Elevated LDL (low density lipoprotein) or “bad cholesterol” can lead to dangerous deposits that can cause a stroke. In general, a low LDL number is desired. HDL (high density lipoprotein) or “good cholesterol” actually protects your body by cleaning your blood vessels from dangerous cholesterol deposits. So a high HDL level is protective for stroke.  

To help normalize cholesterol levels, one can control his or her diet. Eating food low in saturated fat such as fruit, vegetables, lean meats, chicken, fish, etc., preparing foods by baking, broiling, or steaming, as opposed to frying, and eating a high-fiber diet, can help lower cholesterol. Regular exercise can also lower cholesterol.  

New classes of powerful medications including those known as statins, help to lower levels of bad cholesterol and are extremely successful at reducing the risk of stroke by up to 25%. Interestingly, these medications seem to protect against stroke by mechanisms other than just lowering the cholesterol.  

Young adults should have their cholesterol checked about once every five years. Men over age 45 and women over age 55, and those with family histories of high cholesterol, should check their cholesterol every one to two years. Cholesterol can be checked by a simple blood test performed by one’s primary medical physician.  

Heart disease: Coronary heart disease (CHD) such as people with recent (within two weeks) heart attacks or myocardial infarction (MI), or known clogged arteries, and those with congestive heart failure or a low ejection fraction (heart has reduced ability to pump blood) can have increased risk of stroke. Proper treatment of these disorders by your internist or cardiologist can help reduce the risk of stroke.  

Atrial fibrillation: Atrial fibrillation is the most common type of arrhythmia (abnormal heart rhythm) in the elderly population. The incidence of stroke in those with atrial fibrillation increases significantly as the population ages. It is even higher in those who have a history of rheumatic heart disease and mitral stenosis (narrowing of a particular heart valve).  

In those who have atrial fibrillation, the blood thinner warfarin (Coumadin) has been shown to be safe and effective in reducing the risk of stroke. The effects of warfarin last a relatively long time in the body and regular blood testing is required to monitor the effectiveness of the warfarin. Interestingly, aspirin and other types of blood thinners, are not as effective in reducing the risk of stroke from atrial fibrillation, but these are still indicated for those where the use of warfarin is contraindicated. Recent literature suggests that even those older than 75 years of age can safely take warfarin. Those with atrial fibrillation will have to take warfarin indefinitely to ensure reduction of the risk of stroke.  

Diabetes mellitus: Diabetes mellitus is a significant risk factor for stroke. This applies even to those who have very tight control of their blood sugars (this does not mean that those with diabetes mellitus should allow their blood sugars to remain uncontrolled, as there are many other complications associated with elevated blood sugars). Those with diabetes mellitus should also control their blood pressure even more stringently than those without diabetes mellitus in order to prevent the occurrence of stroke.  

Type 1 diabetes mellitus (also known as insulin-dependent diabetes mellitus and IDDM) cannot be prevented as a disease entity. Therefore, the risk of stroke associated with type 1 diabetes mellitus cannot be significantly altered once one is diagnosed with this disease. However, with proper weight control, diet control, and exercise program, type 2 diabetes mellitus (also known as noninsulin-dependent mellitus NIDDM) can be prevented. This is likely the best way to reduce the incidence of stroke associated with diabetes.  

Obesity: Those who weigh greater than or equal to 30% above average weight have an increased risk of stroke. This increased risk of stroke is related to two factors. The first is the obesity itself increases the risk of stroke, and the second is that obesity is associated with other previously discussed risk factors of stroke such as hypertension, diabetes, and hypercholesterolemia. Together these factors are additive.  

Stroke seems also to be more associated with central or abdominal obesity (weight distribution focused in the abdomen).  

Proper diet and exercise programs should be the first steps in managing obesity.  

Other factors: Tobacco use in any form leads to dramatic increases in the incidence of stroke. Cigarettes are the most common form of tobacco used. Although the risk is greater the more you smoke, an increased risk is present even by smoking as little as one cigarette per day. Smoking one cigarette per day can increase one’s risk of stroke by two fold, as compared to a nonsmoker. It is important to realize that no amount of smoking is safe.  

The good news about smoking is that it is also never too late to quit. Within one year of quitting, the risk of stroke due to cigarette smoking is cut in half, and within five years of quitting, your risk of stroke due to cigarette smoking is the same as if you never smoked at all.