Coronary artery bypass surgery, also coronary artery bypass graft surgery, and colloquially heart bypass or bypass surgery is a surgical procedure performed to relieve angina and reduce the risk of death from coronary artery disease. Arteries or veins from elsewhere in the patient's body are grafted to the coronary arteries to bypass atherosclerotic narrowings and improve the blood supply to the coronary circulation supplying the myocardium (heart muscle). This surgery is usually performed with the heart stopped, necessitating the usage of cardiopulmonary bypass; techniques are available to perform CABG on a beating heart, so-called "off-pump" surgery.
Angiography
Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins and the heart chambers. This is traditionally done by injecting a radio-opaque contrast agent into the blood vessel and imaging using X-ray based techniques such as fluoroscopy. The word itself comes from the Greek words angeion, "vessel", and graphein, "to write or record". The film or image of the blood vessels is called an angiograph, or more commonly, an angiogram.
Although the term angiography is strictly defined as based on projectional radiography, the term has been applied to newer vascular imaging techniques such as CT angiography and MR angiography.
Technique of performing an Angipgraphy
Depending on the type of angiogram, access to the blood vessels is gained most commonly through the femoral artery, to look at the left side of the heart and the arterial system or the jugular or femoral vein, to look at the right side of the heart and the venous system. Using a system of guide wires and catheters, a type of contrast agent (which shows up by absorbing the x-rays), is added to the blood to make it visible on the x-ray images.
The X-ray images taken may either be still images, displayed on a image intensifier or film, or motion images. For all structures except the heart, the images are usually taken using a technique called digital subtraction angiography (DSA). Images in this case are usually taken at 2 - 3 frames per second, which allows the radiologist to evaluate the flow of the blood through a vessel or vessels. This technique "subtracts" the bones and other organs so only the vessels filled with contrast agent can be seen. The heart images are taken at 15-30 frames per second, not using a subtraction technique. Because DSA requires the patient to remain motionless, it cannot be used on the heart. Both these techniques enable the radiologist or cardiologist to see stenosis (blockages or narrowings) inside the vessel which may be inhibiting the flow of blood and causing pain.
Angioplasty
Angioplasty is the technique of mechanically widening a narrowed or obstructed blood vessel; typically as a result of atherosclerosis. Tightly folded balloons are passed into the narrowed locations and then inflated to a fixed size using water pressures some 75 to 500 times normal blood pressure (6 to 20 atmospheres).
The word is composed of the medical combining forms of the Greek words aggeîos meaning "vessel" and plastós meaning "formed" or "moulded". Angioplasty has come to include all manner of vascular interventions typically performed in a minimally invasive or percutaneous method.
The current success rate for bypass surgery is 96 to 98 percent.
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