Coronary Artery Disease

Coronary artery disease occurs as a result of blockages in the arteries supplying the heart, also known as the coronary arteries. These blockages are called atheroma, and are a type of fatty deposit that accumulates on the walls of vessels. If the atheroma get large enough they can rupture or burst, which triggers a clotting mechanism in the blood that may produce a clot that could completely block the coronary artery. This is what most commonly causes a heart attack.

Symptoms of coronary artery disease

All of the above symptoms caused by ischemic heart disease are related to a lack of blood supply (ischemia) to the heart muscle. This is due to a blockage of the coronary vessels by atheroma. Depending on the degree of ischemia the symptoms will be more or less severe. However some conditions such as diabetes may mask some of the symptoms, most commonly reducing the amount of chest pain to little or none at all.

Investigations for coronary artery disease

At a later stage an echocardiogram (heart ultrasound) should be performed to test the heart's function and rule out any valvular disease. An exercise stress test should also be performed to rule out any ischemia while the heart is under stress during exercise.

However the gold standard for investigations of ischemic heart disease is a coronary angiogram. This is performed when there is a significant suspicion that there is sufficient atheroma present to cause ischemia of the heart muscle. It involves threading a wire from vessels in the groin up to the coronary vessels of the heart, radio-opaque dye is then injected into the coronary vessels and visualized with x-ray. Blockages by atheroma can then be identified and possibly be reduced by angioplasty or stent insertion.

Treatment of coronary artery disease

Lifestyle and diet modification is crucial in the treatment of ischemic heart disease. This is because studies have shown that there are a number of risk factors that increase an individual’s risk of developing ischemic heart disease. These include:

Therefore it is important to reduce as many of these risk factors as possible. A healthy balanced diet and exercise will help to reduce high cholesterol, hypertension and diabetes. Quitting smoking will also significantly reduce your risk of ischemic heart disease, as well as many other diseases!

There are a wide range of medications used to treat coronary artery disease. Some of these include:

• Nitrates- these include glyceryl trinitrate (GTN) and isosorbide mononitrate (ISMN). They act by helping to dilate vessels and thereby reduce any blockages that may be present.
• Calcium channel blockers- these include amlodipine, verapamil and diltiazem. Calcium channel blockers act in a similar way to nitrates by causing vessels to dilate, they can also act directly on the heart by reducing the amount of work that it performs reducing its demand for blood supply.
• Beta blockers- these include metoprolol, atenolol, bisoprolol and carvedilol. These act by reducing the heart rate and thereby reducing the amount of work the heart is performing.
• ACE inhibitors- these include ramipril, enalapril and perindopril. These also reduce the amount of work that the heart has to do and increase it’s functionality.
• Statins- these include simvastatin, atorvastatin and pravastatin. These reduce the cholesterol level in the blood, thereby reducing the risk of atheroma forming.
• Blood thinning medications- these include aspirin, clopidogrel, heparin and Clexane. These medications help to thin the blood and reduce the risk of clots forming which may increase the blockage of a coronary artery.

Different combinations of the above medications may be used in people with coronary artery disease depending on individual risk factors and other co-morbidities. However if the ischemic heart disease is severe enough surgical intervention may be required.

The most common surgical intervention used today is coronary angioplasty, which is an extension of the investigative procedure described above where the blockage is reduced either by manipulation of the blockage (basket retrieval, balloon inflation etc) or by stent insertion. These measures help to reduce the size of the atheroma or blockage and reestablish blood flow to the heart muscle.

A coronary artery bypass graft or CABG is also regularly performed in severe ischemic heart disease. This involves open heart surgery to replace the blocked coronary artery with another vessel from a different part of the body, such as the leg or arm.

Prognosis of coronary artery disease

Coronary artery disease is a serious medical condition and it is important to treat it quickly. Lifestyle modification and diet change is a vital part of treating ischemic heart disease and is just as important as starting medications. If you suspect you may have ischemic heart disease it is important to see your local physician or GP as soon as possible.