A coronary angiography, also known as a coronary catheterization, is a procedure that gives both visual and tactical access to coronary circulation and blood filled chambers of the heart for both diagnostic and interventional purposes. It is one of many diagnostic tests used in cardiology. More specifically, coronary catheterization recognizes occlusion, stenosis, thrombosis or aneurismal enlargement of the walls of the coronary arteries; heart chamber size; heart muscle contraction performance; and various aspects of heart valve function. In addition, internal blood pressures can be measured during the procedure.
Coronary angiography was first performed in 1929 by a German physician who inserted a plastic tube into his own vein and guided it to his heart. In 1960, new advances in coronary angiography were made due to an accidental error on a pediatric patient. Around this time, coronary catheterization was taking several hours. Today, it can be successfully performed in less than one hour.
The only indications for coronary catheterization are significant cardiac risks and/or symptoms. For example, a patient under age 40 with diabetes presenting with chest pain would be a candidate for coronary catheterization. Additionally, patients with symptoms of angina or myocardial infarction should have a cardiac catheterization.
Since patient feeling is often more accurate than medical monitors in recognizing procedure safety, patients are usually awake during the procedure, and only a mild anesthetic is used. The procedure is performed in a hospital’s cath lab with specially-trained nurses standing by. The patient lays flat on a radiolucent table, which has small x-ray sources on the opposite side of it. Usually starting at the femoral artery in the groin, a physician will guide a small, flexible catheter into the patient’s artery all the way until it reaches the opening of a coronary artery. The catheter is transparent and allows a watery radiocontrast dye to be intermittently mixed with the blood flow during the procedure. This allows the physician to see how it flows through the arteries and identify any problems.
Every three to five seconds, the dye is washed out into the coronary capillaries and veins, so injections are needed frequently. In order to monitor the interarterial blood pressures, the catheter is smaller than the diameter of the artery, also known as the lumen. The guiding catheter also allows the physician to push instruments through it and into the artery to a lesion site.
There are minimal risks to coronary catheterization when performed by an experienced team. There is a risk of hemorrhage at the site of insertion, however, pressure will be held in that area for at least 30 minutes to prevent this. Other less frequent problems include cardiac tamponade, heart attack, injury to an artery, and allergies to the dye.
Image Caption: Coronary Angiography. Credit: Bleiglass/Wikipedia (CC BY-SA 3.0)