Heart blockage is a term commonly used by patients referring to coronary artery disease, a build up of plaque causing narrowing of the arteries that supply the heart muscle with blood. This heart blockage, if severe enough can prevent the muscle getting the blood it needs to function, especially at times when more blood flow is required such as when exercising, leading to symptoms such as chest pain and shortness of breath.
Various tests can be used to see if there are areas of the heart that have compromised blood flow, such as exercise stress tests and nuclear scans. These tests are not perfect however, and in patients determined to be at significant risk, the standard way to directly assess the heart blockage is to look at the outline of the actual vessel itself with a procedure called a coronary angiogram as seen in the pictures below.
Heart Blockage – Normal Coronary Arteries
Look at the picture above. There are three arteries that run over the surface of the heart and supply it with blood, see the diagram above. There is one artery on the right side, and two arteries on the left side. The one on the right is known as the right coronary. On the left side, which is the main side, we have the left anterior descending (LAD) that runs down the front of the heart and supplies the front and main wall, and then the left circumflex that supplies the sidewall. If you look carefully, a major artery called the left main artery supplies the LAD and the circumflex. The left main artery and even the LAD artery are so important that critical blockages in these arteries are known as the Widowmaker!
The picture above shows what we call angiographically normal coronary arteries. The artery appears smooth with no irregularity. The reason we call it that is that although it looks normal by angiogram, and there is clearly no significant heart blockage there may be deposition of plaque in the walls of the artery that cant be seen on this test. That can still progress over time, and it’s why patients at risk of coronary artery disease should still pay close attention to minimizing the risk factors for this despite no visual heart blockage and an apparently ‘normal’ angiogram.
Heart Blockage – Mild Coronary Artery Disease
The diagram above shows an artery with some blockages that are in the 20-40% range. Typically we call heart blockage less than 40% mild. Such blockages are clearly not causing restriction to blood flow and therefore very unlikely to be causing symptoms. It is important to note however is that there is clear evidence here of progressive coronary artery disease and such patients need aggressive attention paid to risk factors for coronary disease (cholesterol, diabetes, smoking, blood pressure etc.), appropriate medicines, and it is important to stress things such as lifestyle changes such as exercise, weight loss and dietary modification. Paying close attention to these things can prevent progression of heart blockage and help to stabilize it. Don’t forget it is often the mild heart blockage that can become unstable and burst leading to a heart attack.
Heart Blockage – Moderate Coronary Artery Disease
A moderate amount of heart blockage is typically that in the 40-70% range, as seen in the diagram above where there is a 50% blockage at the beginning of the right coronary artery. Usually heart blockage in the moderate range does not cause significant limitation to blood flow and so does not cause symptoms. Moderate coronary artery disease is treated much in the same way as mild disease, basically attention to risk factors, medications, and healthy lifestyle modification. Occasionally heart blockage at the higher end of the moderate range (50-70%) may require additional testing to see if it is significant or not and may be responsible for symptoms.
Heart Blockage – Severe Coronary Artery Disease
Severe heart blockage is typically that in the greater than 70% range. This degree of narrowing is associated with significantly reduced blood flow to the heart muscle and can underlie symptoms such as chest pain and shortness of breath. In the diagram above an 80% blockage can be seen at the beginning of the vessel. This is actually a bypass graft in someone that has had bypass surgery. The severe heart blockage caused symptoms and was treated with placement of a stent as can be seen in the picture. Sometimes bypass surgery is required in the setting of multiple severe blockages.
Heart blockage – Totally Occluded Artery, Big Heart Attack!
As can be seen in the picture above there is a 100% blockage at the beginning of the right coronary artery stopping blood flowing any further and of course leading to a heart attack. Such a heart blockage is typically accompanied by major symptoms and treatment needs to be given in a very timely manner. As can be seen in the picture, this artery was treated with stent placement to allow normal blood flow to resume. If the treatment for this isn’t done within good time (usually first few hours, the sooner the better) then the heart muscle may die and once dead cannot usually recover which results in reduced heart pumping function and heart failure.
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