Coronary angiography is an X-ray of the heart and blood vessels of a living patient. The X-ray is taken with a moving camera, which produces a very detailed and accurate picture of the condition of the coronary arteries. The procedure is considered invasive (involving entry into the living body), because a thin, flexible tube called a catheter is inserted into an artery, usually in the groin. The catheter then must be threaded through the circulatory system to the heart. A dye that will appear on the X-ray film is injected through the catheter while the pictures are taken. The dye may produce a temporary burning sensation, and some patients experience some nausea and possibly an urge to urinate. After the procedure is completed, the patient rests to allow the incision to heal. The patient is also observed to make sure there are no negative reactions to the procedure, such as bleeding, clotting, or sensitivity to the dye.
Researchers had tried since the 1930s to develop a technique for viewing coronary arteries, which is considered necessary for diagnosing and treating coronary artery disease. Early coronary angiography faced two major problems. First, the procedure required that enormous amounts of contrast agent (or dye) be injected, which often caused serious side effects. Secondly, the procedure produced only one radiographic plate. Success became more likely when serial (successive) film changers and image intensifier were introduced in 1949. Film changers allowed for true motion cinematography, or pictures taken with a moving camera.
Until the late 1950s physicians would not allow the dye to enter the heart itself, believing that patients would experience ventricular fibrillation (an irregular contraction of the heart that frequently causes cardiac arrest, or heart attack). In 1958 Mason Sones, a physician at the Cleveland (Ohio) Clinic, was conducting an angiogram on a patient. He intended the dye to go only as far as the aorta (main artery branch that carries blood from the left side of the heart to the arteries of all limbs and organs except the lungs), but the catheter slipped inside the heart. When the patient experienced no ill effects from the dye and the X-ray films were so much better than previous angiography, a new standard was established.
Sones's coronary angiography became widely used. Considered the "gold standard" for diagnosing coronary artery disease, angiography is now done so frequently that it is almost commonplace. But the procedure is very expensive (one 1995 analysis priced angiography at $5,500 per procedure). Doctors have less expensive—and less direct, or non-invasive—ways of assessing the health of the heart, such as an echocardiogram (an ultrasound of the heart) and exercise tests. A study published in the Journal of the American Medical Association (JAMA) in 1992 found that of patients who were told they needed angiography, 80 percent did not actually need it.
Other studies reveal that physicians are not as likely to recommend angiography for their female patients, even when they exhibit the same symptoms as male patients who receive the procedure. More studies need to be conducted to find out whether women are being deprived of the test, or whether they are being handled more appropriately than male patients. In any event, the American College of Cardiology (ACC) and the American Heart Association (AHA) have joined to create specifications on how angiography should be used.