CORONARY artery disease is currently the number one cause of death in all populations and across all regions of the world except sub-Saharan Africa. Globally, it kills approximately eight million persons per year, which makes it far more deadly than stroke, diabetes, hypertension, diarrhoeal diseases and infectious diseases such as HIV, malaria and dengue. Local data implicates it as the cause of 37 per cent of our deaths. This translates to approximately 7,000 deaths per year in Jamaica, which is five times the number of people who are murdered annually and twice the number who die from cancer.
What is coronary artery disease?
As we age, fat and cholesterol are deposited along the lining of our arteries in soft, fatty deposits called plaque. This process starts in childhood and progresses throughout life in all arteries in all human beings. The process is called atherosclerosis and it is part of the normal ageing process in humans. In most people, this plaque does not grow to the point where it becomes large enough to impede blood flow. However, conditions such as diabetes, hypertension, obesity, cigarette smoking and high cholesterol levels accelerate the rate at which such deposition occurs. In such cases, the plaque deposits can become so large that they impede blood flow along the affected arteries. When this process involves the coronary arteries, blood flow to the heart muscle is eventually compromised and coronary artery disease is diagnosed.
What are the symptoms?
Symptoms vary, but the classic symptom is central or left-sided pressing chest pain which comes with exertion and is relieved by rest. This is called angina. Other symptoms include shortness of breath, fatigue, sweating and dizziness. The occurrence of these symptoms suggests that there is a critical narrowing in one or more of the coronary arteries.
Interestingly, women who have this disease often develop atypical symptoms such as dizziness, shortness of breath and fatigue rather than chest pain. Women are also more likely than men to attribute their symptoms to other causes such as breast and joint pain, and are less likely to seek medical attention promptly. These unfortunate facts mean that coronary artery disease often goes undiagnosed in women until it is relatively advanced.
What are the complications?
Plaque deposits have a soft centre and a thin covering which can easily rupture (tear), causing platelets and clotting factors in the blood to stick to the site of rupture. When this happens the narrowed segment of the artery rapidly narrows further and may even become completely blocked. At this point all blood flow to the heart muscle ceases. The heart muscle, now starved of blood and oxygen, dies, causing severe, crushing chest pain as it does so. This is called a heart attack and it is a major cause of death and disability in people with coronary artery disease.
Repeated heart attacks in different areas of the heart may cause the heart to become weak, flabby and enlarged. This is called a cardiomyopathy and it may result in heart failure which manifests as shortness of breath (especially on lying flat), swelling of the legs and body and profound weakness.
How is coronary artery disease treated?
Treatment of coronary artery disease must be individualised to reflect the extent and severity of the disease as well as the patient's own unique circumstances and preferences. In general, though, it involves medications which relieve symptoms, other medications which prolong life and prevent complications, and various procedures which improve blood flow to the heart muscle. These procedures include using various tiny balloons to open blocked arterial segments, followed by the placement of a metal cage (called a stent) in the vessel. The purpose of the stent is to prevent the now opened vessel from closing again. In extreme cases, bypass surgery is required.
As we can now appreciate, coronary artery disease and its complications pose a challenge even to contemporary medicine. Understanding the disease, its symptoms, complications and treatment are key elements in limiting the burden of this dreadful disease on our population.
Dr Handel Emery is a consultant cardiologist at the Winchester Heart Centre.