Coronary Artery Diseases
admin / February 2, 2019
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Introduction
Coronary artery disease
is the narrowing or blockage of the artery or arteries supplying
blood to the heart muscle. This narrowing is caused by plaques,
which are cholesterol deposits on the vessel wall, resulting in
abnormal and gradual thickening of the lining of the heart
arteries (a condition known as atherosclerosis). The narrowing
usually develops slowly over many years. |
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Causes Patients who smoke, or have conditions such as diabetes mellitus, hypertension and high blood cholesterol or fat levels are prone to developing coronary artery disease. The heart has three main coronary arteries. Patients are said to have single, double, or triple-vessel disease, depending on the number of vessels that are narrowed. When the narrowing becomes critical, the patient can develop symptoms such as chest pain or shortness of breath. In medical terms, this is called angina. The cholesterol plaque causing the blockage can sometimes rupture suddenly, causing a blood clot to form. This blood clot will cut off blood supply and cause damage to the heart muscle. This is called myocardial infarction, commonly known as a “heart attack”. The patient may get severe chest pain, shortness of breath, palpitations, giddiness, cold sweaty hands, and even die suddenly. The severity and prognosis of the heart attack depend on the percentage of the heart muscle damaged. Minor heart attacks usually recover. Major heart attacks can result in long-term heart failure, enlargement of the heart, abnormal heart rhythms, heart valve leakage and even death. |
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Treatment Treatment for coronary artery disease is dependent on the extent of the disease and the symptoms experienced by the patient. 1) Lifestyle changes Eating a healthy and balanced diet, with more vegetables or fruits, is important in protecting our heart arteries. Food that are rich in fats, particularly saturated fats, can lead to a higher level of cholesterol, which is a major component of the deposits that contribute to the narrowing of heart arteries. Regular exercise plays a vital role in keeping the heart healthy. Exercise helps us to become fitter and build a stronger circulatory system. It also helps us to lose weight. Obesity is unhealthy, as it leads to a higher incidence of hypertension, diabetes mellitus, and high lipid levels, all of which can damage the heart arteries. 2) Controlling major risk factors of coronary artery disease Diabetes mellitus, smoking, high cholesterol level, and high blood pressure are four major factors that lead to higher risk of coronary artery disease. Good control of these four major risk factors through lifestyle changes and/or medication can help to stabilise the progress of atherosclerosis, and reduce the risk of complications such as heart attack. 3) Medical therapy Various medications are helpful for patients with coronary artery disease. Among the common ones are: · Aspirin / Clopidogrel / Ticlopidine These medications thin the blood and reduce the likelihood for a blood clot to form on top of the narrowed heart arteries, therefore reducing the risk of a heart attack. · Beta-blockers (e.g. Atenolol, Bisoprolol, Carvedilol) These medications help to reduce the heart rate and blood pressure, thus reducing the symptoms of angina as well as protect the heart. · Nitrates (e.g. Isosorbide Dinitrate) These medications work by opening the heart arteries, and therefore improving the blood flow to the heart muscle and reducing symptoms of chest pain. A short-acting form of nitrates, Glyceryl Trinitrate, usually given as tablets or a spray to be administered under the tongue, is commonly used for immediate relief of chest pain. · Angiotensin-Converting Enzyme Inhibitors (e.g. Enalapril, Perindopril) and Angiotensin Receptor Blockers (e.g. Losartan, Valsartan) These medications allow the blood to flow from the heart more easily, and also help to lower the blood pressure. · Lipid-lowering medications (e.g. Fenofibrate, Simvastatin, Atorvastatin, Rosuvastatin) These medications lower the levels of ‘bad’ cholesterol (Low-Density Lipoprotein), which is one of the commonest reasons for early or advanced coronary artery disease. Such medications are a mainstay of coronary artery disease therapy. 4) Percutaneous Coronary Intervention This is a minimally invasive method of ‘unblocking’ a narrowed heart artery. Through a plastic sheath placed in an artery in either the groin or the wrist, a balloon can be delivered to the narrowed segment of the heart artery, where it is then inflated to open up the narrowing. Thereafter, a small wire mesh tube (stent) can be deployed to help keep the artery open. Stents can be either plain (bare-metal) or have medication coated on it (drug-eluting). This method can often save the lives of patients with an acute heart attack. For stable coronary heart disease causing chest pain, it can relieve the symptoms of angina very effectively. Generally, patients with single or double-vessel disease can benefit from this method. With triple-vessel disease, or the presence of poor heart function, a surgical procedure known as Coronary Artery Bypass Grafting can often be a good alternative or a better treatment option. 5) Surgery · Coronary Artery Bypass Grafting (CABG) CABG involves the harvesting of another artery or vein from the chest wall, forearm, or leg to build a new route for the blood to flow directly to the heart muscles. It is like building an expressway parallel to the small and narrowed roads. It is a fairly safe operation, with an average risk of death around 2 per cent. In patients without a previous heart attack and who undergo CABG as an elective procedure, the risk can be as low as 1 per cent. The operation is usually done via an incision in the middle of the chest, and incisions in the thigh and forearm (if the artery from the arm is used). The patient’s heart beating is stopped and a heart lung machine is usually used during the surgery. In selected patients, where the conditions are favourable, the surgeon may choose to do the procedure with the heart still beating, using special devices that can stabilise the portion of the heart that is being stitched. The heart lung machine is not required. This is known as off-pump CABG. The National Heart Centre Singapore does about 13 per cent of its CABG operations using this method. · Robotic Surgery In addition, NHCS has also started doing CABG via a robotic surgery programme. The use of these instruments now allows heart surgery to be done using tiny keyhole incisions on the chest wall. This method results in faster recovery, less pain, and much lower risk of wound infection. However, it is suitable for bypassing only one or two vessels. |
Coronary artery disease is the narrowing or blockage of the artery or arteries supplying blood to the heart muscle. This narrowing is caused by plaques, which are cholesterol deposits on the vessel wall, resulting in abnormal and gradual thickening of the lining of the heart arteries (a condition known as atherosclerosis). The narrowing usually develops slowly over many years.