What is Coronary Heart Disease?
Coronary heart disease (CHD) is a group of diseases characterized by the buildup of plaque within the walls of blood vessels. Plaque builds up inside the arteries leading to the heart muscle. When plaque clogs up the arteries, it causes a build-up of pressure in these arteries which leads to chest pain and shortness of breath. A high concentration of cholesterol in the blood is another cause of CHD.
As the plaque continues to build up in the arteries, it can eventually cause a narrowing of these arteries. Narrowed arteries reduce and can even cut off the blood supply to the heart and its muscles, leading to chest pain (angina) or a heart attack.
Less common causes of CHD include abnormalities of the structure of the heart and lifestyle factors such as smoking, obesity and lack of exercise.
Atherosclerosis is a condition in which plaque builds up in the walls of arteries. This build-up narrows the arteries and decreases the flow of blood to your heart, brain, and other organs.
Other names for atherosclerosis include:
Atherosclerotic vascular disease
Hardening of the arteries
Disease of the arteries (Arteriosclerosis)
What are the types of coronary heart disease?
The build-up of plaque in the walls of your arteries occurs over many years. Most often, there are no symptoms for decades.
The process of plaque build-up is called atherosclerosis. The narrowing and blockage of blood vessels by the plaque is called coronary artery disease (CAD).
CAD can affect the arteries that supply blood to your:
Brain (Cerebral artery disease)
Face (Peripheral artery disease)
Heart (Coronary artery disease)
Kidneys (Renal artery disease)
Limb muscles (Peripheral artery disease)
Lungs (Pulmonary artery disease)
Stomach (Gastrointestinal artery disease)
When CAD occurs in the arteries leading to and within the heart, it is called coronary heart disease (CHD).
What causes coronary heart disease?
There are several factors that can cause coronary heart disease:
High blood pressure (hypertension)
High blood cholesterol (HDC)
Lack of exercise
Elevated levels of lipoprotein (a)
Autoimmune diseases (such as rheumatoid arthritis and lupus)
Family history of heart disease
Stress and depression
What are the symptoms of coronary heart disease?
The following are the most common symptoms of CHD:
Chest pain or discomfort
Shortness of breath or rapid breathing
Painfully swollen legs
Nausea and vomiting
How is coronary heart disease diagnosed?
Your doctor will begin the diagnosis with a detailed medical history and a physical examination.
Diagnostic tests may include:
Chest x-ray or CT scan to rule out a lung infection or other diseases that can cause similar symptoms
Transthoracic echocardiogram (ultrasound of your heart) to evaluate the size and structure of your heart
Blood tests to detect diseases that can cause similar symptoms—such as anemia, thyroid disease, or kidney disease
Blood clots (Thrombus) that form along the walls of the narrowed or blocked arteries from atherosclerosis can break off and travel to other parts of your body. A clot that travels to your brain can cause a stroke. Blood clots can also narrow or block blood vessels to the lungs or the kidney, causing chest pain or shortness of breath and kidney failure, respectively.
How is coronary heart disease treated?
Your treatment will depend on the exact location of the blockage, the amount of artery blocked, your age and overall health, and other factors.
If the artery is severely blocked, it may be necessary to place a stent (a metal or plastic tube) to keep the blood flowing to your heart muscle. If the artery is moderately blocked, medications—such as certain blood pressure drugs—may be prescribed.
Coronary Artery Bypass Graft (CABG)
Because of its low survival rate, this operation is no longer used to treat coronary heart disease.
Coronary Artery Bypass Graft (CABG) is the most widely used operation to treat narrowing or blockage of the coronary arteries. During this operation, a healthy artery or vein from another part of your body is taken and grafted onto the coronary arteries. By doing this, blood flow is rerouted around the blocked section of the coronary artery.
Because of the times when a blockage is in an area that makes it difficult or impossible to remove and replace the artery, two techniques have been developed—the saphenous vein graft and the internal mammary artery graft.
Saphenous vein graft
During this operation, a vein from the leg is removed and grafted onto the coronary artery. This is the most common operation used to bypass the coronary arteries. This is because the legs contain healthy veins close to the skin’s surface (the saphenous veins).
Internal Mammary Artery Graft
The internal mammary arteries (IMAs) are two arteries that branch off the aorta and run toward the chest. Unlike the saphenous veins, the IMAs stay on the heart’s surface, which makes them more accessible.
This operation is usually performed when the coronary artery to be repaired is in a difficult location. This means that it is risky to remove a vein from the leg to use on the artery. Instead, the IMA is used as a bypass to reduce complications such as bleeding and infection.
This operation is more common in women and in younger patients. Also, the IMA grafts have a greater tendency to narrow over time when used in bypass operations.
Other operations may be used to treat narrowing or blockages of the coronary arteries. These include:
Atrial septectomy. In this operation, your doctor will remove part of an atrium (the upper chambers of the heart) to correct abnormalities such as an abnormal heart rhythm causing the atria to quiver uncontrollably. This operation will not, however, correct narrowing or blockages in the coronary arteries.
Angioplasty. During angioplasty, a small balloon on a catheter (a narrow flexible tube) is passed through an artery and into the coronary artery. Once the catheter is in place, the balloon is inflated to push the clot or plaque against the artery wall.
A mesh wick is then threaded over the catheter. As the catheter is pulled back over the wick, it slowly pulls the wick—and the clot or plaque—back through the artery to be removed from the body.
Bypass surgery. During bypass surgery, the procedure used to treat narrowing or blockages in the coronary arteries is bypass surgery.
This operation uses arteries or veins from the chest or legs to reroute blood flow around the blocked coronary artery. The blockage and sections of the coronary artery that supply blood to the heart muscle are then removed. The vessels (from the chest or legs) used to do this are sewn into the coronary artery in their place.
This operation is the most effective way to ensure normal blood flow to the heart muscle. It is, however, a more invasive and complex surgery than angioplasty or atherectomy. As a result, it is usually reserved as a treatment of last resort.
There are three types of bypass operations, with each type used depending on the location and extent of the blockages:
Off-pump coronary artery bypass: In this procedure, the patient’s heart is still beating when the operation begins. The surgeon pulls the chest wall muscles aside and makes an incision between the ribs to access the coronary artery. The artery is then removed from the aorta and bypassed.
The vessel is sewn into place and the incision in the chest wall is closed with stitches.
On-pump coronary artery bypass: In this procedure, the heart is stopped and blood is pumped continuously through the body by a machine (cardiopulmonary bypass). A separate incision is made into a large blood vessel in the leg or arm. This incision is used to access the coronary artery to remove plaque and widen the artery.
A synthetic tube called a graft is sewn into place to bypass the blockage. The aorta is then sewn back together.
Off-pump coronary artery bypass with arterial graft: This is a combination of the two previous operations where the heart is still beating when the operation begins. The surgeon makes an incision between the ribs to access the coronary artery. He or she then removes plaque and widens the artery as with off-pump coronary artery bypass.
Artery is then sewn into place and the incision in the chest wall is closed with stitches.
What are the risks of heart surgery?
As with any major operation, there is always a risk of complications. However, the chance of a successful operation and a full recovery are very good.
The specific complications that may occur are related to the type of surgery you will undergo. These include:
Blood clots or additional blockages in blood vessels (heart attack or stroke)
Pain in the chest or prolonged soreness
Stitches coming undone
Damage to blood vessels or nerves in the chest wall
What will happen during and after surgery?
During your hospital stay, you will be monitored very closely by medical staff. This is to ensure that your heart and your blood flow to the heart are working properly before you are allowed to leave.
To ensure there is no additional damage to your heart, you will be placed on bed rest for several days. Once transferred from the intensive care unit, you will be able to sit up, watch television and read. You will also be encouraged to walk around your hospital room.
Most patients are able to go home within a week of surgery. Before you are discharged, you will be given a list of restrictions. These may include no smoking, no heavy lifting or physical exertion and possibly a low-cholesterol diet.
You may also be scheduled to see your doctor again in a month. Depending on your recovery, you may require further treatment.
Make sure you understand and follow all your doctor’s orders. If you have any questions, do not hesitate to ask.
Learn more about Cardiac Bypass.
Sources & references used in this article: