Cardiovascular disease, i.e. heart disease and diseases of the circulatory system, causes one death every three minutes in the UK alone. Coronary heart disease is the largest cause of death within this group; it is the biggest single killer in the UK and indeed continues to be the leading cause of death worldwide.
The majority of deaths from coronary heart disease are due to myocardial infarction (heart attack). Furring up of the arteries (atherosclerosis) is a slow process whereby fatty deposits build up in the walls of the arteries supplying the heart with blood, and over time these deposits can harden and form plaques. Plaques are at risk of rupture, and in this event the undersurface of the artery lining is exposed, provoking an injury response. Anyone who has ever had so much as a papercut will have noticed that the body is quick to create a clot over the wound to halt blood loss and prevent infection. The injury response in arteries is similar, however in this instance the clot formation can block the blood flow through the artery, starving the muscle it supplies of oxygen – otherwise known as a heart attack.
A heart attack carries a high risk of mortality with fewer than one in ten people who suffer one outside of the hospital environment (known as an “out of hospital arrest”) surviving to be discharged home.
There are frequently no warning signs that a patient has cardiovascular disease, and often a heart attack out of the blue will be the first sign of a problem. There are, however, several risk factors which predispose to heart disease, such as:
Many of these can be modified by changes in lifestyle (for example, by eating more healthily, maintaining an ideal body weight, exercising and giving up smoking) and, if necessary, medication (such as statins to lower cholesterol and drugs to lower blood pressure). Most of these risk factors can be readily identified by a doctor undertaking a thorough medical history and examination, together with a simple fasting blood test.
This information can also be entered into a cardiovascular risk calculator called the QRISK2, which determines an individual’s likelihood of sustaining a heart attack or stroke in the next ten years. Anyone with a risk calculated at 10% or higher is now being advised to address the modifiable aspects of their lifestyle to bring their risk down to below 10%, and those that are unable to do so are being offered medication to help lower their risk.
Rather than treat patients empirically based on a perceived risk inferred from population statistics, more modern non-invasive technology has made it possible to individualise potential treatment by looking for the very beginnings of disease in the arteries supplying the heart (coronaries) and those supplying the brain (carotids) with simple tests such as the CT coronary angiogram and carotid artery ultrasound. This has taken screening to a more detailed and personal level such that a patient’s risk can be far more accurately defined and treatment can be offered to those who have been proven to have disease rather than those who are simply at risk.
Screening is not just undertaken to look for coronary artery disease, but in certain circumstances may also be used to look for a number of other cardiac conditions. For example, if one family member is born with a heart abnormality (known as congenital heart disease) or is found to have a heart muscle abnormality known as a cardiomyopathy, there is a risk that other family members may be similarly affected. Screening for such conditions will usually involve an ECG and some form of imaging, such as echocardiography in the first instance, with a view to more sophisticated investigations such as 24 hour ECG monitoring and cardiac MRI (CMR), or even genetic testing, as necessary.