Cardiovascular disease
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Explainer Video
Summary
Cardiovascular disease
In a nutshell
Cardiovascular diseases (CVD) impact the blood vessels or the heart. There are various risk factors, such as high blood pressure, that can increase the chance of developing cardiovascular diseases. This summary details the development of CVD and how to interpret data relating to CVD.
Cardiovascular disease
Definition
Cardiovascular disease (CVD) is a general term describing diseases impacting the blood vessels or the heart.
Example
Coronary heart disease (CHD) is the most common cardiovascular disease and it occurs when the blood vessels that supply the heart are blocked due to a build up of fatty substances.
Formation of atheromas
The endothelium is the inner arterial lining and it can become damaged due to high blood pressure. When damage occurs, white blood cells and lipids from the blood will be deposited under the lining to form fatty streaks.
Over time, calcium salts and fibrous tissue will also build up in the deposit. A hard swelling called a plaque forms and the artery will lose some of its elasticity. This is called an atheroma.
The plaque will block some of the lumen of the artery and cause it to narrow. This makes it more difficult for heart to pump blood around the body. Consequently, this causes a rise in blood pressure which in turn increases the chance of damage to the endothelial lining. This is a positive feedback loop.
Aneurysms
Definition
Atheromas will increase the risk of aneurysms. When part of an artery becomes narrower and less elastic, blood can build up and cause a bulge swelling. This is an aneurysm. The aneurysm can burst which causes a haemorrhage.
Thrombosis
If an atheroma bursts through the endothelium, the artery wall will be damaged. This can trigger the accumulation of platelets and the protein thrombin. These will form a thrombus (blood clot). This may block the artery or it may become dislodged and travel around the body. It may also settle elsewhere in the body and block a different artery.
Myocardial infarctions
Definition
A myocardial infarction is more commonly known as a heart attack. This may occur when a coronary artery is blocked.
The coronary arteries supply the heart muscle with oxygenated blood and a blood clot in one of these will deprive the heart muscle of oxygen. As a result, the cells will not be able to carry out respiration.
A heart attack can damage (or even kill) the heart muscle. Symptoms of a myocardial infarction include chest pain and shortness of breath.
Risk factors of cardiovascular disease
There are various factors that increase the risk of cardiovascular diseases. These are explained in the table below.
Risk factor | Explanation |
| High blood cholesterol | High blood cholesterol () increases the risk of cardiovascular diseases as cholesterol is a primary component of an atheroma that build up in the arteries. The presence of an atheroma will increase the blood pressure and also increase the risk of blood clots. Blood cholesterol can be raised by a poor diet. Example
|
| Smoking | Carbon monoxide is present in cigarette smoke and this reduces the oxygen supply to the cells by combining with haemoglobin. The reduction in oxygen may trigger a heart attack. Nicotine is also found in cigarette smoke and it narrows the blood vessels. Smoking also decreases the antioxidant level in the blood which increases the risk of cellular damage to the arteries. |
| High blood pressure | High blood pressure increases the risk of artery damage which will increase the risk of atheroma formation. Consequently, this will cause a rise in blood pressure which in turn increases the chance of damage. This is a positive feedback loop. |
To reduce the risk of cardiovascular diseases, lifestyle changes can be made. However, there are some factors, like a genetic predisposition, that can not be controlled.
Data interpretation
When interpreting data there are various steps you should take.
Interpretation step | Example |
Describe the data | The relative risk of developing cardiovascular diseases increases as the blood pressure increases. |
Draw conclusions from the data | There is a positive correlation between blood pressure and the risk of developing cardiovascular diseases. |
Check the validity of conclusions | It is important that the data supports the conclusions. This data only shows male data therefore the conclusion above can not be made. It is also important to note that using the data in the graph you can only conclude that there is a correlation and not a causation between the two factors. |
Conflicting evidence
Sometimes different studies will indicate conflicting results. There are some questions to consider when this occurs.
Examples
- What was the sample size of each study?
- What was the study design like?
- Which other factors may have impacted the results?
- Did the two studies use similar groups of participants?
To overcome this conflicting evidence, more studies should be carried out and other scientists should reproduce the results in order to confirm the results.
FAQs - Frequently Asked Questions
How does high blood cholesterol increase the risk of cardiovascular diseases?
High blood cholesterol increases the risk of cardiovascular diseases as cholesterol is a primary component of the atheroma that build up in the arteries. The presence of the atheroma will increase the blood pressure and also increase the risk of blood clots. Blood cholesterol can be raised by a poor diet.
What is a myocardial infarction?
A myocardial infarction is more commonly known as a heart attack. This may occur when a coronary artery is blocked. The coronary arteries supply the heart muscle with oxygenated blood and a blood clot in one of these will deprive the heart muscle of oxygen. As a result, the cells will not be able to carry out respiration.
What is coronary heart disease?
Coronary heart disease (CHD) is the most common cardiovascular disease and it occurs when the blood vessels that supply the heart are blocked due to a build up of fatty substances.