Cardiac Information
What is a stroke?
A stroke has the same relationship to the brain as a heart attack does to the heart; both result from a blockage in a blood vessel that interrupts the supply of oxygen to cells, thus killing them. Blood is supplied to the brain through two main arterial systems: the carotid arteries that come up through the front of the neck and the vertebral arteries that come up through the rear of the neck. Brain cells require a constant supply of oxygen to stay healthy and function properly. The brain receives about 25% of the body's oxygen supply, but it cannot store oxygen; a reduction of blood flow for even a short period of time can be disastrous. The consequences of a stroke, the type of functions affected and the severity, depend on where in the brain the blockage has occurred and the extent of the damage. A stroke is usually defined as either ischemic or hemorrhagic, depending upon whether it is caused by a blockage in an artery or by a tear in the artery's wall that produces bleeding in the brain.
What are the risk factors of stroke?
The American Stroke Association has identified several factors that increase the risk of stroke. The more risk factors a person has, the greater the chance that he or she will have a stroke. Some of these you can't control, such as increasing age, family health history, race and gender. But you can change, treat or modify most other risk factors to lower your risk. Factors resulting from lifestyle or environment can be modified with a healthcare provider's help.
- Increasing age -- The chance of having a stroke more than doubles for each decade of life after age 55. While stroke is common among the elderly, many people under 65 also have strokes.
- Sex -- The latest data show that, overall, the incidence and prevalence of stroke are about equal for men and women. However, at all ages, more women then men die of stroke.
- Heredity (family history) and race -- The chance of stroke is greater in people who have a family history of stroke. African Americans have a much higher risk of disability and death from a stroke than whites, in part because blacks have a greater incidence of high blood pressure, a major stroke risk factor.
- Prior stroke -- The risk of stroke for someone who has already had one is many times that of a person who has not.
- High blood pressure -- High blood pressure is the most important risk factor for stroke. In fact, stroke risk varies directly with blood pressure. Many people believe the effective treatment of high blood pressure is a key reason for the accelerated decline in the death rates for stroke.
- Cigarette smoking -- In recent years, studies have shown cigarette smoking to be an important risk factor for stroke. The nicotine and carbon monoxide in cigarette smoke damage the cardiovascular system in many ways. The use of oral contraceptives combined with cigarette smoking greatly increases stroke risk.
- Diabetes mellitus -- Diabetes is an independent risk factor for stroke and is strongly correlated with high blood pressure. While diabetes is treatable, having it increases a person's risk of stroke. People with diabetes often also have high cholesterol and are overweight, increasing their risk even more.
- Carotid artery disease -- The carotid arteries in your neck supply blood to your brain. A carotid artery damaged by atherosclerosis (a fatty buildup of plaque in the artery wall) may become blocked by a blood clot, which may result in a stroke. If you have a diseased carotid artery, your healthcare provider may hear an abnormal sound in your neck, called a bruit (BROO ee), when listening with a stethoscope.
- Heart disease -- People with heart problems have more than twice the risk of stroke as those whose hearts work normally. Atrial fibrillation (the rapid, uncoordinated beating of the heart's upper chambers) in particular raises the risk for stroke. Heart attack is also the major cause of death among stroke survivors.
- Transient ischemic attacks (TIAs) -- TIAs are "mini strokes" that produce stroke-like symptoms but no lasting damage. They are strong predictors of stroke. A person who's had one or more TIAs is almost 10 times more likely to have a stroke than someone of the same age and sex who hasn't.
- High red blood cell count -- A moderate or marked increase in the red blood cell count is a risk factor for stroke. The reason is that more red blood cells thicken the blood and make clots more likely.
What other factors can affect the risk of stroke?
- Season and climate -- Stroke deaths occur more often during periods of extremely hot or cold temperatures.
- Socioeconomic factors -- There's some evidence that people of lower income and educational levels have a higher risk for stroke.
- Excessive alcohol intake -- Excessive drinking (an average of more than one drink per day for women and more than two drinks per day for men) and binge drinking can raise blood pressure, contribute to obesity, high triglycerides, cancer and other diseases, cause heart failure and lead to stroke.
- Certain kinds of drug abuse -- Intravenous drug abuse carries a high risk of stroke from cerebral emboli. Cocaine use has been closely related to strokes, heart attacks and a variety of other cardiovascular complications. Some of them have been fatal even in first-time cocaine users.
How are heart disease risk factors related to stroke?
Other risk factors are secondary risk factors for stroke. They affect the risk of stroke indirectly by increasing the risk of heart disease:
- High blood cholesterol and lipids
- Physical inactivity
- Obesity or overweight
Stroke is a medical emergency, call 9-1-1!
Know the warning signs!
- Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
- Sudden confusion, trouble speaking or understanding
- Sudden trouble walking, dizziness, loss of balance or coordination
- Sudden trouble seeing in one or both eyes
- Sudden severe headache with no known cause
Every 53 seconds, someone in America has a stroke. About 600,000 Americans will have a stroke this year - and 160,000 of them will die. In fact, stroke is our nation's No. 3 killer and one of the leading causes of disability. But we're fighting back. The American Heart Association spends more on stroke-related research and stroke-related programs than any other not-for-profit organization, second only to the federal government. In November 1998, the American Heart Association renamed its Stroke Division. It is now the American Stroke Association...a division of the American Heart Association.
How Serious Are Strokes?
A stroke is always serious; unlike cells in other parts of the body, those in the brain cannot be repaired or regenerated. It is the third leading cause of death in the US. About 160,000 Americans die of stroke each year. Stroke is also responsible for more injuries from falls than any other medical condition.
Studies have indicated that one-third of all strokes are fatal within the first 30 days, although mortality rates are declining. Over half of stroke victims survive beyond five years. People who suffer ischemic strokes have a much better chance for survival than those who experience hemorrhagic strokes, however. In addition to brain cell death caused by any stroke, complications of hemorrhagic stroke include increased pressure on the brain or spasms in the blood vessels, both of which can be very dangerous.
In general, a third of those who survive either an ischemic or hemorrhage stroke suffer some neurologic problems, and nearly all have at least some injury in the brain. In one small study, survivors of hemorrhagic stroke had a greater a chance for recovering better function than those who suffered ischemic stroke. In all, however, 90% of stroke survivors experience varying degrees of improvement after rehabilitation. One small 1998 study reported that people who survived for many years after a stroke had a chance for independent living that was about the same as for their peers who had not suffered strokes. The stroke patients even appeared to be less depressed.
The risk for recurring stroke within five years is about 22%, with the risks highest in those who had suffered a hemorrhagic stroke, in people with diabetes, and in the elderly. In patients with embolic strokes, alcoholism, valvular heart disease, atrial fibrillation, nausea and vomiting are specific risk factors for early recurrence. The risk for recurrence for any stroke is highest within the first six months, so preventive measures should be instituted as soon as possible.
Stroke Support Group
Plaza Medical Center of Fort Worth offers a Stroke Support Group for stroke survivors and family.
- Second Thursday of each month
- 6:00 p.m. ~ Classroom A/B