About 700,000 Americans will have a stroke this year—that's one person every 45 seconds. Fortunately, you can reduce your chance of suffering a stroke by gaining a greater understanding of how this condition occurs and by identifying common risk factors and symptoms.
A stroke can occur by two different mechanisms. When a blood vessel (artery) leading to or within the brain becomes blocked this event is called an "ischemic stroke.” Blood carries oxygen and nutrients to the cells in your brain and when the blood flow stops even for just a few minutes, the cells begin to die. As a result, these cells can lose their ability to function. Alternatively, a “hemorrhagic stroke” can occur if a blood vessel within the head ruptures and leaks blood into the surrounding brain tissue. This bleeding causes acute swelling and compression of brain tissue leading to cell death.
The specific physical abilities that will be lost or affected by a stroke depend on the extent of cell death and where in the brain the stroke occurred. The brain is divided into four primary parts.
If the stroke starves oxygen-rich blood from these brain regions, the following related functions will be affected:
- The left hemisphere — Controls the right side of the body, speech, language and memory
- The right hemisphere — Controls the motor function of the left side of the body, depth perception, recognition of faces, body parts and other everyday items, short term memory, problem solving, social judgment and reasoning
- The cerebellum — Controls balance and coordination
- The brain stem — Controls life-support functions such as breathing, blood pressure and heartbeat, eye movements, hearing, speech and swallowing
Some factors that increase your risk of stroke are genetically determined. Others simply happen naturally or are due to lifestyle. The factors resulting from heredity or natural processes can't be changed, but those that are environmental can be modified with the help of our comprehensive approach to vascular care.
The five uncontrollable risk factors include:
- African American heritage
- Family history of diabetes
- Family history of stroke
The basic controllable risk factors include:
- Treatable medical disorders—diabetes, atrial fibrillation, heart attack, high blood pressure, high cholesterol, heart disease, personal history of stroke or TIA, and patent foramen ovale (or "PFO," an abnormal opening between the right and left sides of the heart)
- Excessive alcohol intake
- Drug abuse (especially cocaine)
- Physical inactivity
- Low estrogen in women
The risk of stroke is greatly reduced by lowering your blood pressure, smoking cessation, beginning or increasing exercise, controlling medical problems, maintaining optimal weight and eating a healthy diet.
The warning signs of a major stroke are:
- Sudden weakness or clumsiness (occasionally with numbness) of the face, arm or leg on one side of the body
- Loss of speech, or difficulty speaking (i.e. garbled words)
- Acute dimness or loss of vision in one eye – often described as a shade coming down over the field of vision in one eye
"Temporary strokes" (transient ischemic attacks or TIAs) can occur days, weeks or even months before a major permanent stroke. The symptoms occur rapidly and last a relatively short period of time, usually from a few minutes to several hours. The usual symptoms are like those of a major stroke, except that the signs and symptoms are temporary, typically lasting 24 hours or less. If you experience a TIA, you may be up to 9 times more likely to suffer a major stroke in the near future.
Screening and Diagnosis
Assessing your level of risk is an important step that you can take to prevent a stroke. The St. Joseph Hospital Vascular Institute offers a comprehensive screening program to help you get this critical information. Screenings include a medical history, physical examination and blood tests to check for high cholesterol or other conditions that may contribute to atherosclerosis. An ultrasound examination of your carotid arteries, the blood vessels in your neck that are the primary blood supply to the brain, will also be performed to determine if there is significant disease (a.k.a. atherosclerosis). An ultrasound is a non-invasive examination that uses ultrasound waves, instead of X-rays, to visualize the neck and other peripheral arteries. For more information, click here.
Time is critical. Until a few years ago, acute strokes were regarded as untreatable. Brain cells were thought to die within minutes after a stroke began, so acute treatment was believed to be useless. Now researchers have discovered that treatment following a stroke, especially if begun within three hours of onset, can help preserve brain tissue. At the St. Joseph Hospital Vascular Institute, advances in treatment and rehabilitation have also made it possible for many stroke patients to regain full function and quality of life. Treating a stroke depends on where the stroke occurred in your brain and whether it's ischemic or hemorrhagic. The doctor may use magnetic resonance imaging (MRI), computed tomography (CT) scan or angiography (injecting dye through a catheter inserted into the suspected blocked blood vessel and taking x-rays of the vessels) to determine the stroke type and location.
Some of the cutting-edge treatments offered at the St. Joseph Hospital Vascular Institute include:
Carotid Endarterectomy -this is a minimally invasive surgical procedure that removes plaque from the affected carotid artery. The procedure requires a small incision in the neck so that the diseased artery can be exposed for surgical manipulation. The operation involves gentle plaque extraction from the opened vessel once blood has been appropriately thinned and clamps have been applied to the carotid artery above and below the area of arterial disease. The repaired artery is then closed using synthetic patch material. During the procedure ultrasound is used to ensure a perfect result. Once completed, normal blood flow is restored to the brain and the inside of the diseased blood vessel is restored to a clean, smooth surface that reduces the risk of future stroke events.
There is a small risk of having a stroke during the surgical procedure. The recommendation of the Stroke Council of the American Heart Association is that the stroke rate for carotid artery surgery, for symptomatic patients should be 5% or less and 3.5% or less for asymptomatic patients. The vascular specialists at St. Joseph Hospital have recently analyzed their long-term results of carotid endarterectomy. They have a remarkably low operative stroke rate of 0.45% for all patients (symptomatic or not) and a 0% mortality rate.
Carotid Stenting -this is a minimally invasive endovascular procedure that uses guidewire and catheter techniques to traverse the disease within the carotid artery and then perform balloon angioplasty and stent deployment. These maneuvers essentially tack down the plaque and increase the artery’s flow diameter. Arterial access is usually gained from the femoral artery in the groin but also occasionally from a larger artery in the arm.
Similar to carotid endarterectomy, there is a risk of having a stroke during the angioplasty/stenting procedure due to the dislodging of debris (embolization) from the diseased artery. Most recent large clinical series including our own data demonstrate that the stroke risk is higher with this procedure compared to endarterectomy, especially in patients over age 80. However, in the skilled hands of St. Joseph Hospital vascular specialists the procedure is usually well tolerated if the appropriate patient is chosen for treatment.
- Plasminogen activator (t-PA) – this drug can be given intravenous or intra-arterial during the acute phase of a stroke to help dissolve the blood clot that typically forms within the blocked artery in the brain. This emergency treatment is only performed at tertiary care centers such as St. Joseph Hospital and can be life-saving if given within the first 4 to 6 hours of stroke symptoms. It is therefore critical to seek emergency medical attention at the first signs or symptoms of an acute stroke.
Most stroke patients can benefit from rehabilitation, and today the outlook for stroke patients is more hopeful than ever before. Because of advances in treatment and rehabilitation available at the St. Joseph Hospital Vascular Institute, many stroke patients are being restored to a fully functional life.
To learn more about stroke visit the American Stroke Association website at www.strokeassociation.org.