Virtual Medical Centre

Ischaemic Stroke

• What is Ischaemic Stroke?
• Who gets Ischaemic Stroke?
• Predisposing Factors
• Progression
• Probable Outcomes
• How Will Ischaemic Stroke Affect Me?
• Clinical Examination
• How is Ischaemic Stroke Diagnosed?
• How is Ischaemic Stroke treated?
• Ischaemic Stroke References
• Drugs/Products Associated with Ischaemic Stroke

What is Ischaemic Stroke?

3D Animation on Stroke This animation brought to you by Blausen Medical Communications. Contact Andrew Walbank.

A stroke or cerebrovascular accident (CVA) occurs when a blood vessel that carries oxygen and nutrients to the brain is blocked by a clot (ischaemic stroke), or bursts and bleeds (haemorrhagic stroke). As a result, part of the brain cannot get sufficient blood (and hence cannot get enough oxygen and nutrients), and starts to die. Ischaemic stroke can be due to: Thrombosis - local blockage of an artery as a result of disease in the blood vessel wall. Embolism - particles of debris originating elsewhere block arteries supplying a particular part of the brain. Systemic hypoperfusion - general inadequate blood supply that may affect the brain as well as the other organs.

Who gets Ischaemic Stroke?

In the United States:

• The number of new or recurrent stroke cases is about 700,000 every year.
• On average, a stroke occurs every 45 seconds.
• Stroke is the third leading cause of death, killing about 157,000 people a year.
• Men are at a higher risk than women for stroke.
• In 2003, the stroke death rates per 100,000 population for specific groups were 51.9 for white males, 50.5 for white females, 78.8 for black males and 69.1 for black females.

In Australia:

• Stroke is also the third largest cause of death, and one of the leading causes of disability.
• There are over 48,000 new cases of stroke a year, with a stroke occurring every 11 minutes.
• At the current rate, this figure is predicted to reach 74,000 by the year 2017.
• One third of stroke patients die in the first 12 months.
• More than 50% of strokes occur in people under 75 years old, and 5% are under the age of 45.

In general, ischaemic stroke accounts for around 80% of all strokes, and haemorrhagic stroke makes up about 20%.

Predisposing Factors

Risk factors for ischaemic stroke include:

• Age (the risk doubles with every 10 years)
• High blood pressure
• High cholesterol
• Smoking
• Diabetes mellitus
• Heart disease
• Previous stroke
• Family history of stroke
• Atrial fibrillation (irregular heart rhythm)
• Transient ischaemic attacks (TIA) - warning strokes. Even though the symptoms disappear after a short time, TIAs are strong indicators of a possible major stroke.
• Thrombophilia (conditions that make the blood more prone to clotting, especially in young patients).

General Cardiovascular Disease 10-Year Risk Calculator

This risk assessment tool is based on data from the Framingham Heart Study to estimate 10-year risk for general cardiovascular disease outcomes (coronary death, myocardial infarction, coronary insufficiency, angina, ischaemic stroke, haemorrhagic stroke, transient ischaemic attack, peripheral artery disease, heart failure). This tool is designed to estimate risk in adults aged 30-74 years of age without CVD at baseline examination. Use the calculator below to estimate 10-year risk.

Predictors

Age		years
		Male	Female
Gender
		Yes	No
Have you been diagnosed with Type II diabetes?
Are you a smoker?*
Are you prescribed medication to lower your blood pressure?
If you do not know the following blood pressure and cholesterol parameters ask your General Practitioner on your next visit.
Systolic blood pressure**		mmHg
Total cholesterol***	mmol/L      OR	mg/dl
HDL cholesterol****	mmol/L      OR	mg/dl

Results

Significant (> 20%)
Elevated (10–20%)
Mild risk (< 10%)
You have a significant risk of future cardiovascular disease requiring aggressive risk factor modification. You should see a health professional to ensure appropriate management.

• If diabetic, your sugar levels should be well controlled.
• Continue to avoid tobacco use or if you are a smoker, consider stopping this is something your General Practitioner can help you with.
• Blood pressure should be monitored closely. If elevated you should consider either lifestyle modification or appropriate medication. Your general Practitioner can advise you on this.
• Cholesterol levels should be assessed at least annually. Depending on your level, you might be advised to commence lifestyle changes or medication.

Significant (> 20%)
Elevated (10–20%)
Mild risk (< 10%)
You have an elevated risk of future cardiovascular disease requiring risk factor modification. You should see a health professional to ensure appropriate management.

• If diabetic, you should aim for your sugar levels to be well controlled.
• Continue to avoid tobacco use or if a smoker, consider stopping this is something your general practitioner can help you with.
• Blood pressure should be monitored closely. If elevated you should consider either lifestyle modification or appropriate medication. Your general Practitioner can advise you on this.
• Cholesterol levels should be assessed at least annually. Depending on your level you might be advised to commence lifestyle changes or medication.

Significant (> 20%)
Elevated (10–20%)
Mild risk (< 10%)
You have a mild risk of future cardiovascular disease, consider risk factor modification. You may like to see a health professional to ensure appropriate management.

• If diabetic, you should aim for your sugar levels to be well controlled.
• Continue to avoid tobacco use or if a smoker, consider stopping this is something your general practitioner can help you with.
• Blood pressure should be monitored closely. If elevated you should consider either lifestyle modification or appropriate medication. Your general Practitioner can advise you on this.
• Cholesterol levels should be assessed at least annually. Depending on your level you might be advised to commence lifestyle changes or medication.

^*For these purposes "smoker" means any cigarette smoking in the past month.
^**Use current blood pressure, regardless of whether the person is on antihypertensive therapy.
^***Total cholesterol values should be the average of at least two measurements obtained from lipoprotein analysis.
^****HDL cholesterol values should be the average of at least two measurements obtained from lipoprotein analysis.

References:

1. D'Agostino RB, Vasan RS, Pencina MJ, Wolf PA, Cobain M, Massaro JM, Kannel WB. General cardiovascular risk profile for use in primary care: the Framingham Heart Study. Circulation 2008; 117: 743-753.
2. National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) final report. Circulation 2002; 106: 31433421.
3. Stancoven A, McGuire DK. Preventing macrovascular complications in Type 2 Diabetes Mellitus: glucose control and beyond. American Journal of Cardiology 2007; 99: 5H-11H.

Progression

As mentioned earlier, ischaemic stroke can be due to thrombosis, embolism or systemic hypoperfusion.

Thrombotic stroke

Thrombotic strokes are those in which clot formation reduces blood flow, or a clot breaks off and travels to a later part of the blood vessel. Thrombotic strokes can be divided into large and small vessel disease. Thrombosis-related symptoms progress in a stepwise or stuttering fashion, with some periods of improvement.

Embolic stroke

Embolism (particles of travelling debris originating elsewhere) may be from the heart, the aorta or other large vessels. Symptoms often start suddenly and improve very quickly.

Systemic hypotension

Reduced blood flow is more global and does not affect isolated regions. Symptoms are more generalised and without a particular focus, in contrast to thrombosis and embolism.