A new study shows that people who take the commonly used blood thinning drug warfarin may have larger amounts of bleeding in the brain and increased risk of death if they suffer a hemorrhagic stroke. The study is published in the September 30, 2008, print issue of Neurology, the medical journal of the American Academy of Neurology.
Warfarin is commonly prescribed to prevent blood clotting. Studies have shown it helps prevent ischemic stroke for patients with an abnormal heart rhythm called atrial fibrillation. However, if the drug makes the blood too thin, it can increase the risk of brain hemorrhage, a type of stroke caused by bleeding in the brain.
The study involved 258 people who had brain hemorrhage, 51 of whom were taking warfarin. Participants were 69 years old on average and lived in or near Cincinnati. The group underwent brain scans to confirm the type of stroke. The brain scans were used to measure the size of the blood clots.
The study found that people who took warfarin and suffered a brain hemorrhage while their international normalized ratio (INR) was above three had about twice as much initial bleeding as those not taking warfarin. However, this effect was not seen in people whose blood was less likely to clot as determined by an INR of less than three. An INR test measures the blood's ability to clot.
"Warfarin is very effective for preventing ischemic strokes among people with atrial fibrillation and for most patients with this condition it is the right choice," said study author Matthew L. Flaherty, MD, with the University of Cincinnati and member of the American Academy of Neurology. "However, people who have bleeding into the brain while taking warfarin are at greater risk of dying than other people with hemorrhagic stroke. Our study may help to explain why. Fortunately, we did not see larger blood clots in people with an INR of less than three. For most patients on warfarin, the goal INR is between two and three. This shows the importance of good monitoring and adjustment of warfarin dose. People should talk to their doctors about the proper management of warfarin and learn the signs of stroke so they can get to an emergency room immediately if a stroke occurs."
To learn the five signs of stroke, visit www.giveme5forstroke.org. Give Me Five for Stroke is a joint campaign of the American Academy of Neurology, the American College of Emergency Physicians and the American Heart Association/American Stroke Association to encourage people to recognize stroke symptoms, call 9-1-1, and get to the emergency department.
The study was supported by the National Institute of Neurological Disorders and Stroke and a University of Cincinnati College of Medicine Medical Student Summer Research Fellowship.
The American Academy of Neurology, an association of more than 21,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as stroke, Alzheimer's disease, epilepsy, Parkinson's disease, and multiple sclerosis.
For more information about the American Academy of Neurology, visit http://www.aan.com/.
About Cardiovascular disease
Cardiovascular disease is a broad term that includes several more specific cardiovascular conditions. Cardiovascular disease is the leading killer in the US.
Common heart conditions include:
Arrhythmias. Irregular, or abnormally fast or slow, beating of the heart. The heart beat is controlled by electrical impulses. When the timing or frequency of these electrical impulses are disrupted, arrhythmias develop. Some arrhythmias are quite serious. An example is ventricular fibrillation, a severely abnormal heart rhythm that causes death unless treated right away by providing an electrical shock to the heart (called defibrillation). Others are less severe but can develop into more serious conditions over time. A particular concern is atrial fibrillation. Atrial fibrillation is rapid, irregular beating of the upper chambers of the heart. The chambers can quiver instead of beating in a regular pattern. Blood is not fully pumped out of them and may pool and clot.
Cardiomyopathy. A weakening of the heart muscle or a change in heart muscle structure. It often results in inadequate heart pumping or other heart function abnormalities. These can result from various causes, including prior heart attacks, viral or bacterial infections, and others.
Congenital Heart Disease. Malformations of heart structures, present during pregnancy or at birth. These may be caused by genetic factors or by adverse exposures during pregnancy. Examples include holes in the walls that divide the heart chambers, abnormal heart valves, and others. Congenital heart defects can disrupt the normal flow of blood through the heart. Congenital heart defects are the most common type of major birth defect.
Coronary Heart Disease (CHD). CHD is the most common type of heart disease. CHD occurs when the coronary arteries, that supply blood to the heart muscle, become hardened and narrowed due to the plaque buildup. The plaque buildup and the narrowing and hardening of the arteries is called atherosclerosis. Plaques are a mixture of fatty substances including cholesterol and other lipids. Blood flow and oxygen supply to the heart can be reduced or even fully blocked with a growing plaque. Plaques may also rupture and cause blood clots that block arteries. CHD can lead to a heart attack. Angina, the most common symptom of CHD can also occur. Angina is chest pain or discomfort that occurs when the heart muscle is not getting enough blood. Irregular heart beats, called arrhythmias, can develop.Over time, CHD can weaken the heart muscle and lead to heart failure, a serious problem where the heart cannot pump blood the way that it should.
Heart Attack. A heart attack , also called a myocardial infarction may occur when blood supply to the heart is severely reduced or completely blocked. When blood flow is restricted the heart muscle cells do not receive enough oxygen and begin to die. The more time that passes without treatment to restore blood flow, the greater the damage to the heart. This damage can cause irregular heart rhythms or even sudden cardiac arrest or stopping of the heart beat. Death can result. Coronary artery disease is the chief underlying cause of a heart attack. A less common cause of a heart attack is a severe spasm of a coronary artery that reduces the blood supply to the heart.
Heart Failure. This may also be called congestive heart failure or chronic heart failure. Heart failure is a condition where the heart cannot pump enough blood and oxygen to meet the needs of other body organs. Heart failure does not mean that the heart has stopped, but that it cannot pump blood the way that it should. Heart failure is a serious condition. There is no cure for heart failure at this time, except a heart transplant. Once diagnosed, medicines are needed for the rest of the person's life.
Peripheral Arterial Disease (PAD). Hardening of the arteries that supply blood to the arms and legs. PAD is usually the result of atherosclerosis, the buildup of plaque and narrowing of the arteries. Blood flow and oxygen to the muscles in the arms and legs can be reduced or even fully blocked. Painful leg muscles, numbness, swelling in the ankles and feet, and weak pulse in the feet are some of the signs and symptoms of PAD.
Rheumatic Heart Disease.This condition is damage to the heart valves and other heart structures due to inflammation and scarring caused by rheumatic fever, which occurs from streptococcal infection.Heart disease is an umbrella term for a number of different diseases affecting the heart.Heart disease is a number of abnormal conditions affecting the heart and the blood vessels in the heart.
About Stroke A
stroke is an interruption of the blood supply to any part of the brain. A
stroke is sometimes called a "brain attack." Types of strokes
stroke is the most common type of stroke. Usually this type of stroke results
from clogged arteries, a condition called atherosclerosis. Fatty
deposits collect on the wall of the arteries, forming a sticky substance called
plaque. Over time, the plaque builds up. Often, the plaque causes the blood to
flow abnormally, which can cause the blood to clot. There are two types of
- Ischemic stroke
- Hemorrhagic stroke
- A clot that stays in place in the brain
is called a cerebral thrombus.
- A clot that breaks loose and moves
through the bloodstream to the brain is called a cerebral embolism.
Another important cause of cerebral
embolisms is a type of arrhythmia called atrial fibrillation. Other causes
of ischemic stroke include endocarditis, an abnormal heart valve, and having a
mechanical heart valve. A clot can form on a heart valve, break off, and travel
to the brain. For this reason, those with mechanical or abnormal heart valves
often must take blood thinners.
A second major cause of stroke is bleeding
in the brain hemorrhagic stroke. This can occur when small blood vessels in the
brain become weak and burst. Some people have defects in the blood vessels of
the brain that make this more likely. The flow of blood after the blood vessel
ruptures damages brain cells.
Risk factors/causes of strokes may include:
- High blood pressure is the number one
reason that you might have a stroke. The risk of stroke is also increased
by age, family history of stroke, smoking, diabetes, high cholesterol, and
- Certain medications increase the chances
of clot formation, and therefore your chances for a stroke. Birth control
pills can cause blood clots, especially in woman who smoke and who are
older than 35.
- Men have more strokes than women. But,
women have a risk of stroke during pregnancy and the weeks immediately
- Cocaine use, alcohol abuse, head injury,
and bleeding disorders increase the risk of bleeding into the brain.