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Patient's Guide to Antithrombotic Therapy in Stroke

11/06/2012 07:00 PM EST

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Source: American College of Chest Physicians - PDF
Related MedlinePlus Page: Stroke

Hemorrhagic Stroke Treatment (Beyond the Basics)

11/06/2012 07:00 PM EST

Hemorrhagic stroke treatment

Source: UpToDate
Related MedlinePlus Page: Stroke

Ischemic Stroke Treatment (Beyond the Basics)

11/06/2012 07:00 PM EST

Ischemic stroke treatment

Source: UpToDate
Related MedlinePlus Page: Stroke

Patient information: Ischemic stroke treatment (Beyond the Basics)

Author Louis R Caplan, MD

Section Editor Scott E Kasner, MD

Deputy Editor John F Dashe, MD, PhD

STROKE OVERVIEW

In the United States, approximately 700,000 strokes occur each year, most of which are caused by a blockage in blood flow. This blockage causes a lack of blood flow to portions of the brain. The brain injury is called ischemia (literally, lack of blood).
During a stroke, one or more areas of the brain can be damaged. Depending upon the area affected, a person may lose the ability to move one side of the body, the ability to speak, the ability to see normally, or a number of other functions. The damage may be temporary or permanent, and the function may be partially or completely lost. A person's long term outcome depends upon how much brain is damaged, how quickly treatment begins, and a number of other factors.
Strokes are a leading cause of long-lasting injury, disability, and death. Early treatment and preventive measures can reduce the brain damage that occurs as a result of a stroke. The treatment of a stroke depends upon the type of stroke (eg, ischemic or hemorrhagic), the time since the first stroke symptoms occurred, and the patient's underlying medical problems. General information about the treatment of ischemic strokes is provided here.
A separate topic review is available that discusses the signs, symptoms, and diagnosis of ischemic and hemorrhagic strokes. (See "Patient information: Stroke symptoms and diagnosis (Beyond the Basics)".)
A topic is also available that discusses the treatment of hemorrhagic stroke. (See "Patient information: Hemorrhagic stroke treatment (Beyond the Basics)".)

EARLY STROKE TREATMENT

For people who have an ischemic stroke, the goal of treatment is to restore blood flow to the affected area of the brain as quickly as possible. The medicines used for the early treatment of ischemic stroke are alteplase, aspirin, and anticoagulants.

Alteplase (thrombolytic therapy) — Thrombolytic therapy uses a medication called tissue plasminogen activator (tPA, alteplase). tPA works to dissolve clots that are blocking blood flow within arteries of the brain. The benefit of thrombolytic treatment slowly decreases over several hours. Thus, the earlier the treatment is given, the more likely the artery can be opened.

The use of thrombolytics for acute stroke requires care in a hospital that is able to coordinate emergency services and offers rapid consultation with a neurologist (physician who specializes in the brain) and has intensive care services and imaging (eg, CT scan or MRI). Not all hospitals are able to provide these services, and in this situation it may be necessary to transfer the patient to a hospital that can. It is best if the ambulance or family can bring the stroke patient directly to a hospital that is able to give this care, rather than to transfer the patient later.

Side effects — Overall, it is estimated that alteplase treatment is 10 times more likely to help than to harm. However, approximately 1 in 15 patients who is given thrombolytic therapy develops excessive bleeding (hemorrhage) in the brain; this type of bleeding can be fatal. It is estimated that of 30 patients treated, one is harmed by the treatment.

When used to treat large numbers of stroke patients, the potential benefits of this treatment outweigh the risks; however, in any individual patient, the decision to take thrombolytic therapy is a very personal one.

Aspirin — Antiplatelet therapy helps prevent new clots from developing. Unlike thrombolytic drugs, these agents do not dissolve clots that are already present. They are often used acutely if thrombolytic drugs cannot be given or after thrombolytics have been given.

Aspirin is the only antiplatelet agent that has been established as effective for the early treatment of acute ischemic stroke. Thus, doctors may use early aspirin therapy (within 48 hours of the start of stroke symptoms) for patients with ischemic stroke who are not receiving alteplase or anticoagulants. (See "Antithrombotic treatment of acute ischemic stroke and transient ischemic attack", section on 'Antiplatelet agents'.)
Platelets are tiny cell fragments circulating in the blood that normally clump together to stop bleeding. This clumping leads to the formation of a blood clot. In strokes, platelets clump together and form clots inside of narrowed arteries. The platelet "plug" itself and/or the clot that forms around the plug can block blood flow in the brain.

Anticoagulants — Anticoagulants are often, but incorrectly, referred to as blood thinners. They work by decreasing the formation of additional blood clots. Heparin and low molecular weight heparin are anticoagulants.

Because of the risk of excessive bleeding, anticoagulation is seldom recommended for the treatment of patients with acute ischemic stroke. However, anticoagulant therapy with heparin or low molecular weight heparin is used by some practitioners for certain types of stroke. For example, some doctors use anticoagulants for the early treatment of stroke caused by blood clots that travel from the heart (cardioembolism) in patients who have heart valve disease or severe heart failure, and for patients who have stroke caused by dissection (a tear of the inner blood vessel wall) of a large artery that supplies blood to the brain. (See "Antithrombotic treatment of acute ischemic stroke and transient ischemic attack", section on 'Parenteral anticoagulation'.)

LONG TERM PREVENTION OF ISCHEMIC STROKE

For people who have already had an ischemic stroke, doctors often prescribe medicines that can prevent another stroke from happening. This is called secondary prevention. The treatments for secondary prevention of ischemic stroke include antiplatelet medications, anticoagulants, and surgical procedures to reopen blockages in blood vessels (revascularization).

Antiplatelet therapy — The antiplatelet medicines aspirin, clopidogrel, and the combination of aspirin plus extended-release dipyridamole (Aggrenox) are all acceptable options for preventing recurrent ischemic stroke for patients other than those who have a stroke caused by embolism from the heart. (See "Antiplatelet therapy for secondary prevention of stroke".)

Dipyridamole — Dipyridamole is a medication that may be given after a stroke to reduce the risk of another stroke. It is often given in an extended-release form, which combines dipyridamole with aspirin (called Aggrenox®, which contains extended-release dipyridamole 200 mg and 25 mg aspirin). It is taken two times per day.

Side effects of dipyridamole include headache, stomach upset, and/or diarrhea. Headaches usually improve over the first week.

Clopidogrel — Clopidogrel (Plavix®) is an antiplatelet medication that is also used in patients after stroke to reduce the risk of having another stroke. In a study that compared clopidogrel and aspirin, the risk of stroke, MI, or vascular death, was significantly reduced with clopidogrel treatment compared with aspirin treatment [1].

For this reason, some experts recommend use of clopidogrel for patients who are not treated with the combination of aspirin and extended release dipyridamole, rather than use of aspirin alone. Compared with aspirin, clopidogrel causes a slightly higher frequency of rash and diarrhea, and a slightly lower frequency of stomach upset and gastrointestinal bleeding.
Clopidogrel is not usually recommended in combination with aspirin after a stroke because the combination is no more effective for preventing another stroke than either clopidogrel or aspirin alone, while using the two in combination increases the risk of bleeding in the brain. However, selected patients with a recent acute myocardial infarction, other acute coronary syndrome, or recent arterial stent placement are often treated with the combination of clopidogrel plus aspirin.

Aspirin — Aspirin is effective for preventing ischemic stroke. Most studies have found that 50 to 325 mg/day of aspirin is as effective as higher doses for preventing stroke. Furthermore, lower doses within this range appear to provide the same benefit as higher doses. (See "Antiplatelet therapy for secondary prevention of stroke", section on 'Aspirin'.)

In the United States, one advantage of aspirin compared to other antiplatelet medications is cost; one month of aspirin costs approximately $3 compared to at least $160 per month for combined dipyridamole and aspirin and at least $135 per month for clopidogrel.

Anticoagulant therapy — Anticoagulant therapy is used to prevent stroke for selected patients. As an example, for long-term stroke prevention, virtually all patients with atrial fibrillation who have a history of embolic stroke or transient ischemic attack should be treated with anticoagulation (warfarin or dabigatran) in the absence of contraindications.

Warfarin — Warfarin (Coumadin®) is a pill that is taken by mouth. It is often recommended as a long-term treatment for people who have conditions that promote the formation of blood clots, such as atrial fibrillation of the heart. People who take warfarin must be closely monitored with blood tests to ensure that the correct dose is used and that the risk of excessive bleeding or developing blood clots is minimized. (See "Patient information: Warfarin (Coumadin®) (Beyond the Basics)".)

Dabigatran — Dabigatran (Pradaxa®) is another medication that is used to thin the blood. It is useful for people who have atrial fibrillation of the heart. Dabigatran is taken twice a day. Unlike warfarin, patients who take dabigatran do not need to be monitored with blood tests. However, dabigatran is more expensive than warfarin. (See "Dabigatran: Patient drug information".)

Revascularization — Revascularization is the medical term for reestablishing blood flow to an area. In people who have had a stroke, revascularization usually refers to a surgical procedure (carotid endarterectomy) that opens a blocked artery in the neck (the carotid artery), which improves blood flow to the brain and reduces the risk of stroke. The amount of blockage in the carotid artery can be measured with an ultrasound imaging test, CT angiogram, MRA, or conventional arteriogram. (See "Patient information: Stroke symptoms and diagnosis (Beyond the Basics)".)

Carotid endarterectomy is most successful when it is performed by a vascular surgeon who has specialized training and experience with the procedure. However, even in experienced hands, the procedure has risks, including bleeding, brain injury, stroke, and even death. Some people are likely to benefit from carotid endarterectomy while for others, the risks of the procedure are greater than the potential benefits. Placement of a stent in the carotid artery is another alternative, although this therapy carries a greater risk of stroke and disability, especially in people over the age of 70 years. (See "Management of symptomatic carotid atherosclerotic disease" and "Management of asymptomatic carotid atherosclerotic disease".)

COMPLICATIONS AFTER STROKE

A number of problems can develop in people who have had a stroke. These complications are significant because approximately half of deaths after stroke are due to medical complications. In the days and weeks after a stroke, clinicians, the patient, and family members can work to decrease the risk of some of these complications. Common complications include the following:

Blood clots
Difficulty eating and drinking, which increases the risk of pneumonia and malnutrition
Pneumonia
Urinary tract infection
Bleeding in the digestive system
Falls
Heart attack or heart failure
Bed sores

(See "Medical complications of stroke" and "Stroke-related pulmonary complications and abnormal respiratory patterns" and "Cardiac complications of stroke".)

Blood clots — People who have strokes are at an increased risk of developing blood clots as they recover. A deep vein thrombosis (DVT) is a blood clot that develops in the deep veins of the leg. If the clot breaks off, it can travel to the lung, where it is called a pulmonary embolus (PE). A PE can cause serious, and potentially fatal, changes in blood flow throughout the body. These blood clots occur most often between the second and seventh day after the stroke.

The risk of pulmonary embolism is especially high in stroke patients who have difficulty with moving or walking around during the recovery period. Difficulty walking may be related to paralysis caused by the stroke or to other medical conditions. Lack of movement increases the risk of a deep vein thrombosis
Heparin or low molecular weight heparin is used commonly to prevent blood clots in patients who are recovering from a stroke, especially if the patient has difficulty moving or walking without assistance. In this situation, anticoagulation can help to prevent a blood clot in a deep vein of the leg or a blood clot that travels to the lung (called a pulmonary embolism). (See "Patient information: Deep vein thrombosis (DVT) (Beyond the Basics)".)
Use of an anticoagulant to prevent blood clots is different that anticoagulation used for treatment of an ischemic stroke; the dose used for prevention is typically smaller than that used to treat stroke.
To decrease the risk of blood clots, the patient is encouraged to get up and move around frequently as soon as they are able to do so. A physical therapist is often available to help, especially if the patient has weakness in the legs as a result of the stroke.

Difficulty swallowing — The act of swallowing requires coordination of the nerves and muscles of the tongue, mouth, and throat. The brain damage that occurs as a result of a stroke can cause muscle weakness and difficulty swallowing. Dysphagia is the medical term for difficulty swallowing.

Dysphagia is concerning because it increases the risk of inhaling saliva or food into the lungs, which can cause a type of pneumonia known as aspiration pneumonia. Patients with stroke-related pneumonia have a higher risk of death and a poorer long-term outcome when compared to patients without pneumonia. However, in people who have weakness of one side of the body, dysphagia is often temporary because both sides of the brain and body control swallowing.
To determine if a patient is at risk for inhaling food or drinks into the lungs, a simple water swallow test may be done. If the patient has difficulty swallowing water, the clinician may recommend that the patient not eat or drink anything temporarily. In the meantime, medication and nutrition can be given into a vein. Specific exercises and training programs can help to retrain a person how to swallow despite muscle or nerve damage. An additive to thicken liquids may be recommended.

Urinary tract infection — After a stroke, some men and women have difficulty getting out of bed to empty their bladder. Others have difficulty with urinary leakage or are not able to empty their bladder completely because of muscle weakness. For these reasons, a catheter is often placed inside the bladder, especially during the first few days to weeks after a stroke. However, there is an increased risk of urinary tract infections related to the use of a catheter.

Urinary tract infections are a common complication after stroke, occurring in about 11 percent of patients during the first three months after stroke [2].
There are a number of strategies that can decrease the risk of urinary tract infections in patients who require a catheter. A few of these strategies are listed below:

Use a catheter only when necessary
Remove the catheter as soon as possible
It is not necessary to change the catheter to prevent infections. The catheter should only be changed if it begins to crack or deteriorate or if the patient has a urinary tract infection.
For men, there is a lower risk of infections with a condom-type catheter.
There are not good data to support using antibiotics to prevent infection during catheter use. Antibiotics are recommended to treat a urinary tract infection if it develops.

Nutrition — After a stroke, some patients have difficulty consuming an adequate number of calories. In addition, some patients are underweight or malnourished before their stroke. These problems can interfere with a person's ability to recover from stroke, potentially increasing the risk of long-term disability.

For these reasons, a patient's nutritional status should be evaluated before discharge from the hospital. This includes a review of the patient's past and current body weight, a basic history of the patient's eating habits, blood testing, and a physical examination that focuses on the condition of the eyes, hair, skin, mouth, and muscles.
If a person is not able to consume an adequate number of calories, a feeding tube may be placed through the nose and into the stomach (called a nasogastric tube). If the feeding tube will be needed for more than two to three weeks, a tube can be inserted through the abdomen into the stomach (called a percutaneous endoscopic gastrostomy (PEG) tube). The PEG tube may be removed if the person regains the ability to eat normally.

GI bleeding — Patients who have had a severe stroke, especially those who are in the intensive care unit and require a ventilator to breathe, have an increased risk of developing a bleeding ulcer in the stomach. To lower this risk, a medication can be given to lower the stomach's production of acid.

Heart problems — Heart problems, such as an irregular heart rhythm (called an arrhythmia) or heart attack (called a myocardial infarction) are commonly seen following stroke, with some heart problems occurring in up to 70 percent of people. It is important to determine whether the heart problems are caused by the stroke, unrelated to it, or the cause of the stroke.

Tests often performed to screen for these problems include an electrocardiogram (ECG), blood testing, and continuous monitoring of the heart rhythm (called telemetry). Because a large number of people with ischemic strokes also have coronary artery disease, there is a risk of ischemia (lack of blood flow) in the heart during the stroke. In some cases, the person may not be able to tell the clinician that he or she feels chest pain. The ECG will help the clinician to diagnose and treat heart problems as quickly as possible.
Other heart testing may also be recommended, such as an echocardiogram. This test uses sound waves to examine the heart and the aorta (the large vessel that arises directly from the heart); blood vessels that supply the brain with blood originate from the aorta (figure 1). In some people with embolic strokes, the heart or the aorta is the source of the blood clot that led to the stroke.

Bed sores — Bed sores are areas of skin and underlying tissue that are injured when compressed between a bone (eg, tail bone) and an external surface (eg, a mattress) for a prolonged period of time. Other names for bed sores are pressure sores and decubitus ulcers.

The consequences of this type of skin injury range from mild skin redness to deep ulcers extending down to the bone. The ulcer can be uncomfortable and increases the risk of infection for the patient and also potentially increases the healthcare costs and hospital stay.
Bed sores are common in people with a limited ability to move without assistance, and may be preventable by moving or turning (or being moved by a family member or nurse) at least every two hours. It is recommended that:

Patients should be placed at a 30 degree angle when lying on their side to avoid direct pressure over the hip bone (greater trochanter).
Pillows or foam wedges may need to be placed between the ankles and knees to avoid pressure at these sites.
The heels require particular attention; pillows may be placed under the lower legs to elevate the heels, or special heel protectors can be used.
Elevation of the head of the bed should be limited.

Chair-bound patients may generate considerable pressures over the sit bones (ischial tuberosities); they should probably be repositioned at least every hour.

Falls — After a stroke, many people have difficulty walking due to muscle weakness, paralysis, or lack of coordination. When a person becomes less active or unable to walk, they are at increased risk of bone thinning (osteoporosis) and worsened muscle weakness. These risks greatly increase the chance of breaking a bone after a fall. Falls are one of the most common complications of stroke, occurring in up to 25 percent of patients.

To reduce the risk of falls, several interventions may be helpful:

Muscle strengthening and balance retraining exercises — This may include exercise or rehabilitation programs tailored to an individual's needs and abilities. Group classes, such as Tai Chi, may be helpful for patients who are able to walk without assistance.
Evaluation of fall risk — An evaluation may be recommended to determine if a person is at risk for falling. If there is a risk of falling, treatments (eg, a walker, balance training) may be recommended to decrease the risk.
Home hazards — Home hazards such as poor lighting or loose rugs can increase the risk of falling. The following tips can reduce this risk:

Remove loose rugs, electrical cords, or other items that could lead to tripping, slipping, and falling
Ensure that there is adequate lighting in all areas inside and around the home (including stairwells and entrance ways)
Avoid walking on ice, wet or polished floors, or other potentially slippery surfaces, and avoid walking in unfamiliar areas outside
Ensure that the person has properly fitted, non-slip footwear

OUTCOME AFTER STROKE

A patient's healthcare team can often provide guidance to family members regarding the patient's risk of long-term disability or death. However, it may difficult to know exactly what to expect, and in most cases, it is necessary to watch and wait.

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient information: Stroke (The Basics)
Patient information: Medicines after an ischemic stroke (The Basics)
Patient information: Lowering the risk of having another stroke (The Basics)
Patient information: Transient ischemic attack (The Basics)
Patient information: Aphasia (The Basics)
Patient information: Recovery after stroke (The Basics)
Patient information: Atherosclerosis (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient information: Stroke symptoms and diagnosis (Beyond the Basics)
Patient information: Hemorrhagic stroke treatment (Beyond the Basics)
Patient information: Warfarin (Coumadin®) (Beyond the Basics)
Patient information: Deep vein thrombosis (DVT) (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Antiplatelet therapy for secondary prevention of stroke
Antithrombotic therapy to prevent embolization in nonvalvular atrial fibrillation
Cardiac complications of stroke
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)
Cerebrovascular disorders complicating pregnancy
Clinical diagnosis of stroke subtypes
Cryptogenic stroke
Decompressive hemicraniectomy for malignant middle cerebral artery territory infarction
Definition of transient ischemic attack
Differential diagnosis of transient ischemic attack and stroke
Etiology and classification of stroke
Etiology, clinical features, and diagnosis of cerebral venous thrombosis
Etiology, clinical manifestations, and diagnosis of aneurysmal subarachnoid hemorrhage
Reperfusion therapy for acute ischemic stroke
Headache, migraine, and stroke
Initial assessment and management of acute stroke
Initial evaluation and management of transient ischemic attack and minor stroke
Intracranial large artery atherosclerosis
Lacunar infarcts
Medical complications of stroke
Neuroimaging of acute ischemic stroke
Overview of the evaluation of stroke
Posterior circulation cerebrovascular syndromes
Secondary prevention for specific causes of ischemic stroke and transient ischemic attack
Secondary prevention of stroke: Risk factor reduction
Spontaneous intracerebral hemorrhage: Pathogenesis, clinical features, and diagnosis
Spontaneous intracerebral hemorrhage: Prognosis and treatment
Treatment of aneurysmal subarachnoid hemorrhage

The following organizations also provide reliable health information.

National Library of Medicine

(www.nlm.nih.gov/medlineplus/healthtopics.html)

National Institute of Neurological Disorders and Stroke

www.ninds.nih.gov/disorders/stroke/stroke.htm

American Stroke Association

(www.strokeassociation.org)

National Stroke Association

(www.stroke.org)

Several books are also recommended:

Caplan LR. Stroke, American Academy of Neurology and Demos Publishers, New York 2006.
Hutton C, Caplan LR. Striking back at stroke: a doctor-patient journal, Dana Press, New York 2003.
Hutton C. After a stroke: 300 tips for making life easier, Demos, New York 2005.

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Literature review current through: Oct 2012. | This topic last updated: ago 15, 2011.

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References

GRAPHICS

Anatomy of the aorta

The aorta is the main artery that delivers blood from the heart to the body. The aorta travels through the chest (thoracic aorta) and the abdomen (abdominal aorta).