What Is Stroke Risk Assessment With CHADS

Studies have found that as the CHADS score increases, the annual risk of ischemic stroke increases proportionally. Patients with high CHADS scores  are at significant risk for stroke: 5.9% annual risk with a score of 3; up to 18.2% annual stroke risk for patients with a score of 6.

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Dr. Chi-Ming Chow, MD, FRCPC Cardiologist, talks about how a Family Physician can assess stroke risk in AFib patients using the CHADS score as well as treatment options including anticoagulants.

Quiz: Do You Understand Stroke?

Test your knowledge by answering the following questions:


A transient ischemic attack is also called a mini-stroke.

If you experience a transient ischemic attack (TIA), also called a mini-stroke, you experience a temporary disruption of blood flow to the brain.

An ischemic stroke is less common than a hemorrhagic stroke.

An ischemic stroke is more common than a hemorrhagic stroke and is caused by a blocked artery.

A hemorrhagic stroke is caused by a blood vessel leaking or bursting.

A hemorrhagic stroke is caused by a blood vessel leaking or bursting.

All risk factors for stroke are controllable.

There are both controllable and non-controllable risk factors for stroke.

Following a stroke, your vision may need rehabilitation.

Stroke treatment will depend on what type of stroke you’ve experienced. Depending on the areas of the brain affected, your movement, sensation, speech, language, balance and vision may need rehabilitation.
(Answer all questions to activate)

Dr. Atul Verma, MD, FRCPC, Cardiologist, Southlake Hospital, Toronto discusses how atrial fibrillation patients are assessed for stroke risk based on the CHADS score.

AFib and Stroke Risk Assessment - CHADS Score

During atrial fibrillation, the chambers of the heart are not beating properly. In particular, the upper chambers of the heart which are called the atrium. They beat in a very chaotic and disorganized way. And when that happens, the blood can pool in the chamber and start to form clots.

And unfortunately, if those clots break off and go to the brain, then that is the cause of a stroke. Stroke is probably the most serious risk associated with atrial fibrillation. We know that patients who have atrial fibrillation and other risk factors can have five times the risk of stroke compared to individuals who do not have atrial fibrillation.

And the main way that we treat or prevent strokes from happening is by putting patients on blood thinners. Now, before the only option we had was Warfarin. And unfortunately, Warfarin was difficult to use. It required routine blood monitoring, doses would change, you couldn’t eat certain foods.

Now we have a whole new group of oral anticoagulants or blood thinners that are new, that are easier to use, that can be taken at fixed doses, and that don’t need any routine blood monitoring. And furthermore, they’re also associated with a decreased risk of fatal bleeding, bleeds in the brain which obviously can be very, very serious, and can be just as effective as Warfarin in preventing stroke.

We also know that even amongst patients who have atrial fibrillation, there are those who are at higher risk than others. And in fact there are certain patient characteristics, which we abbreviate with the acronym CHADS, that can highlight patients who are at the absolute highest risk of stroke, and who can benefit from blood thinning therapy.

So, CHADS stands for patients who have congestive heart failure, patients with high blood pressure, patients who are over the age of 65, patients with diabetes, or patients who have had a previous stroke. And if you have any one of these risk factors, you probably need to be on a blood thinner if you have atrial fibrillation.

Compliance is very, very important in patients with atrial fibrillation. Oftentimes, patients are on multiple therapies for their atrial fibrillation. You’re going to be on a therapy potentially for preventing stroke, like a blood thinner, but you may also be on therapies to control the rate of your atrial fibrillation, or to prevent atrial fibrillation from coming back.

If we think about the blood thinners in particular, if the drugs are not taken on a regular basis, and you skip even one or two doses of the drugs, particularly the newer blood thinners, then a lot of that blood thinning activity can wear off. And as soon as it wears off, you’re back at being at a high risk of stroke.

So it’s very important that when you’re taking one of these blood thinners, you shouldn’t be missing even one or two doses of the drug. And there are a number of lifestyle modifications that you can do as well.

For example, if you’re currently smoking, quitting smoking can substantially reduce your risk of stroke. Alcohol is also known to worsen atrial fibrillation and also increase the risk of stroke. So cutting back to no more than one standard alcoholic drink a day or preferably even no alcohol at all would be of benefit.

And then another risk factor is obesity in atrial fibrillation. So healthy eating and exercise to reduce weight is a very important thing that you can do to reduce your risk of stroke and reduce the severity of atrial fibrillation.

If you’re looking for more information on atrial fibrillation, there are a number of people that you can approach. Feel free to approach your family doctor, nurse practitioner, pharmacist, or consult with a specialist, a cardiologist, for example, to find out more information on atrial fibrillation and how you can best treat this problem.

Presenter: Dr. Atul Verma, Electrophysiologist, Newmarket, ON

Local Practitioners: Electrophysiologist

AFib and Stroke Risk Assessment With CHADS for Family Physicians

When you have atrial fibrillation, the risk of stroke goes up by two to four times. However, not all patients have the same risk, so each of them has to be individualized, assessed and to see if it merits being put on an anticoagulant.

We use a tool called CCS65 in Canada. The way we do it is, if the patient is about 65, anticoagulants in general is recommended. If they are less than 65, then we have to assess whether they have one or more risk factors that are pertaining to the CHADS risk factors, including congestive heart failure, hypertension, diabetes, as well as having a history of stroke or TIA.

If there are no other CHADS risk factors as mentioned, but they have a history of coronary artery disease, heart attack, stroke, or they have peripheral arterial disease, then they should be put on aspirin. If there are none of the above that were mentioned, then no aspirin or anticoagulant is needed.

If a patient needs to be put on anticoagulants, as you know there are two types of anticoagulants. Warfarin, being one of the longest in history that we have used over the last 30 to 40 years, but as many of us know, the chance of actually bleeding is much higher. We also have to check the blood, especially the iron now, quite frequently, and also there are potential interactions with many foods as well as medication. So it becomes quite challenging to use Warfarin.

With the NOACs, the novel oral anticoagulants, the interactions with foods as well as drugs are less frequent, and also they can be taken either once a day or twice a day. And also the chance of having a fatal bleed or intracranial bleed is also much less as well.

For patients with atrial fibrillation, apart from controlling the symptoms, as well as making sure the stroke risk is assessed and reduced, it’s also important to remind them to have a good, healthy lifestyle. It’s important to eat healthily, as well as maintaining a healthy weight. And it’s also to assess how much alcohol they take. Often for males we should recommend them to be less than two drinks a day. For female we should be less than one drink a day. And also it’s important for them to quit smoking as well.

If any of your patients have atrial fibrillation, it’s important for you to assess them regarding the symptoms, the risk of a stroke, and also maybe worthwhile having them assessed by a cardiologist regarding some of the potential risk factors that led to atrial fibrillation and also be considered for the appropriate anticoagulant medication.

Presenter: Dr. Chi-Ming Chow, Cardiologist, Toronto, ON

Local Practitioners: Cardiologist

周醫生, (醫學博士,加拿大皇家醫學院內外科院士,心臟科醫生),討論如何用CHADS評估心房顫動病人的中風風險


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