Cardiovascular disease and treatments
Laura Armstrong & Joe Wolfensohn
Teachers
Contents
Recall Questions
This topic requires prior knowledge of the structure and function of the heart and blood vessels, and the double circulatory system.
What is the function of the coronary arteries?
They supply oxygenated blood to the heart muscle.
Describe the difference between arteries and veins.
Arteries carry blood away from the heart under high pressure; veins carry blood back to the heart under low pressure and have valves.
Where does the left side of the heart pump blood to?
The body, to deliver oxygen to body tissues (systemic circulation).
Topic Explainer Video
Check out these @JoeDoesBiology videos that explain cardiovascular disease and treatments, then read the study notes. Once you’ve gone through them, don’t forget to try the practice questions!
What is Coronary Heart Disease (CHD)?
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CHD is an example of a non-communicable disease.
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CHD is caused by layers of fatty material building up inside the coronary arteries.
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This narrows the arteries, reducing blood flow to the heart muscle itself.
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The heart muscle receives less oxygen, reducing the rate of respiration.
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This means less energy is released for muscle contraction and muscle contractions are weaker which can lead to a heart attack.
Risk factors for CHD
The following factors increase the likelihood of developing CHD.
- smoking
- having a high-fat diet
- lack of exercise
- being overweight / obese
- having high blood pressure
- having high cholesterol
Treatments for Cardiovascular Disease
1. Stents
- Mesh tubes inserted into narrowed coronary arteries.
- Keep arteries open and maintain blood flow to the heart muscle.
Advantages:
- Effective long-term.
- Recovery time is short.
- Removes a blockage that has already formed.
Disadvantages:
- Risk of infection.
- Risk of internal bleeding or blood clot formation.
- Risk of damage to blood vessels.
- Risk from anaesthetic used during surgery.
- Need to take anti-clotting drugs after surgery.
2. Statins
- Drugs that reduce blood cholesterol levels.
- Slow down the formation of fatty deposits in the arteries.
Advantages:
- Reduce risk of strokes and heart attacks.
- Improve blood cholesterol levels.
Disadvantages:
- Must be taken long-term.
- May forget to take the medication.
- Possible side effects (e.g. muscle pain, liver damage).
- Wont be effective if the blockage has already formed.
Faulty Heart Valves
- Valves may not open fully or may leak.
- This reduces the efficiency of the heart's pumping action.
Example
- If the valve in the aorta is leaky, less blood will be pumped out of the left ventricle.
- This means less blood is transported around the body.
- Less oxygen reaches the body tissues.
- This means there will be less aerobic respiration and less energy released.
- This will lead to tiredness and weaker muscle contraction.
- More anaerobic respiration will take place which leads to a build up of lactic acid and muscle fatigue.
Treatment:
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Biological valves (from animals / humans) or mechanical valves can be used to replace faulty valves.
Pros and Cons:
|
Valve Type |
Advantages |
Disadvantages |
|
Mechanical |
Long-lasting and durable. No risk of rejection or transmission of disease from animal / human. |
Risk of blood clots around the valve - need to take anti-clotting medication |
|
Biological |
No risk of blood clots around the valve. |
May need replacing after ~10 years. May be rejected by the immune system. Ethical issues surrounding the use of animal tissue. May carry disease from the donor animal / human. |
Heart Failure Treatments
1. Heart Transplant
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Used when the heart cannot pump blood effectively.
Pros:
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Can greatly improve life expectancy and quality of life.
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Should be permanent if successful.
Cons:
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Risk of rejection by the immune system.
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Limited donor availability so may be a long waiting time.
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Immunosuppressants needed (medication to suppress the immune system). This could lead to the patient getting other infections.
2. Artificial Hearts
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Temporary devices used while waiting for a transplant or to allow the heart to rest.
Pros:
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Immediate solution for critical patients. No need to wait for a donor.
Cons:
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High risk of infection and clotting.
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Not long-term solutions.
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Restrictive, requiring a prolonged stay in hospital.
Both require surgery which carries risk of infection and risks from anaesthesia.
Key Terms
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CHD (Coronary Heart Disease) – Build-up of fatty material in coronary arteries.
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Stent – A device used to keep arteries open to increase blood flow.
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Statin – A drug that lowers blood cholesterol.
No answer provided.
Exam Tip
When evaluating treatments, always include both advantages and disadvantages. Use comparative language like ‘whereas’ and ‘however’.
If given information in the question to use in your answer, don’t just copy it out. This will not gain marks. Make sure to add value to it by explaining each statement. See the exam style question below for an example of this.
No answer provided.
Praactice Questions
Explain how a stent works as a treatment for a person with a blockage in a coronary artery. (2 marks)
opens / widens the artery or pushes blockage to the side
so more blood can flow through.
After a patient has a stent fitted, a doctor administers an injection of anti-clotting medicine. The patient is then prescribed a daily anti-clotting tablet.
Information about anti-clotting medicines:
- Highly effective
- May take up to a week to reach full effectiveness
- In clinical use for over 60 years
- Inexpensive to manufacture
- May not work well if the patient eats certain foods
The patient’s blood is checked regularly to ensure the medicine is working.
Evaluate the use of anti-clotting medicines for patients who have received a stent. (4 marks)
Advantages:
- only have to take the tablet once a day
- only a tablet so easy to take or only a tablet so not painful to take
- less likely to get a blood clot
- drugs are cheap so less cost to NHS or drugs are cheap so people can afford them
- drugs have been used for a long time so must be safe / trusted
Disadvantages:
- patients have to make sure they always have a supply of drugs
- patients could forget to take the drugs
- patients could still get a blood clot in the first week
- restrictions on lifestyle because patients have to have a blood test every few weeks
- restrictions on lifestyle because patient can’t eat certain foods
- patients may get a blood clot if they eat the wrong food
- risks associated with puncturing skin / infection
- patient may have a fear of needles
- higher risk of bleeding / bruising
More Practice
Try to answer these practice questions from the TikTok videos on your own, then watch the videos to see how well you did!