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There are still some people who are unsure about what a stroke is. This is perfectly understandable to me since strokes come in two varieties with lots of variation in severity and symptoms.
A stroke is a brain attack, so both types of stroke occur in the brain. However, some strokes are caused by bleeding into the brain (hemorrhagic strokes) and some are caused by the blockage of blood vessels that supply blood, containing nutrients, energy and oxygen, to the brain tissue (ischemic strokes).
A couple of weeks ago, I briefly discussed things you might do to prevent having a stroke in the first place. This column is about preventing ischemic strokes in those people who have already had one.
The leading cause of ischemic stroke is atherosclerotic blood vessel disease, which gives rise to blockage or tightening of major arteries that feed the brain, as well as narrowing of smaller arteries inside the brain. This is the same process that causes heart attacks due to blockage of the coronary arteries, which feed the heart.
There are several risk factors we cannot change that increase the likelihood of this blood vessel disease in both the heart and the brain. These include our age (50 years or older), gender, ethnicity and family history.
However, several conditions can be altered to slow down the disease in the blood vessels. This requires control of risk factors that speed up development of atherosclerosis, such as hypertension (high blood pressure), hyperlipidemia (high cholesterol and/or triglycerides), diabetes mellitus (high blood sugar), obesity and smoking.
If a smoker stops smoking, the risk for stroke decreases to that found in a nonsmoker just five years after stopping.
Other treatment strategies include increasing fruit and vegetable intake, increasing potassium intake and reducing sodium (salt) intake, weight control, regular exercise, and avoidance of heavy alcohol consumption. In older women, postmenopausal hormone therapy is associated with an increased risk for ischemic stroke and should be avoided, especially in those with a previous stroke.
Management of hypertension should aim to achieve a normal blood pressure for the patient, realizing that no specific drug or drug combination is ideal for all patients. Arterial hypertension, defined as systolic blood pressure of more than 140 or diastolic blood pressure of more than 90, is the most important modifiable risk factor for stroke. A 30 to 40 percent reduction in the risk for recurrent stroke can be achieved by reducing blood pressure.
Some evidence suggests that aggressive lowering of cholesterol levels may slightly increase the risk for hemorrhagic (bleed) stroke. However, the benefits of statins to decrease the risk for recurrent ischemic (blockage) stroke and other blood vessel obstructions are thought to outweigh the risk of bleeding. A target range of 70 to 100 for low-density lipoprotein (LDL or bad) cholesterol levels and more than 50 for high-density lipoprotein (HDL or good) cholesterol levels is recommended to prevent recurrent stroke. In patients with diabetes, the target LDL cholesterol level is less than 70.
About 25 percent of patients with stroke also have diabetes mellitus, which increases the likelihood of recurrent stroke. In these patients, the blood sugar must be monitored and kept under strict control along with blood pressure and cholesterol control.
For some people, carotid (neck) artery surgery or stenting may be used in an effort to keep blood flowing continuously to the brain. This may be used in addition to medical treatment and is most effective in patients with severe occlusion of the internal carotid artery.
Virtually all patients who have had an ischemic stroke should take aspirin, or aspirin plus extended-release dipyridamole (Aggrenox), or clopidogrel (Plavix) to thin the blood by keeping platelets from sticking together. Specific choice among these should be guided by the patient’s previous treatment and history of ischemic events as well as allergies or other potential contraindications.
The most important message to those people who have had an ischemic stroke is to follow up with regular visits to your doctor to try to prevent further damage to your brain by monitoring and treating the factors that are otherwise invisible to you.
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