HEART CATHETERIZATION
(Coronary Angiography)
The objective of heart catheterization is to thread a thin plastic tube or catheter through the circulation into the heart for the measurement of pressures and blood flow, and the performance of certain procedures. Coronary arteriography or angiography is a test in which dye is squirted into the heart chambers and coronary arteries, the vessels that supply the heart muscle with blood. Simultaneous X-ray pictures are taken to detect heart muscle and valve abnormalities as well as atherosclerotic blockages of the dye-filled arteries.
Major Indications
1) suspected severe atherosclerotic disease of the coronary arteries. 2) unexplained chest pain or heart failure. 3) disease of the heart valves. 4) evaluation of patients being considered for heart surgery. 5) follow-up evaluation of patients who have had heart surgery. 6) congenital heart disease. 7) assessment of the efficacy of certain heart medications. 8) performance of the following procedures: thrombolysis (dissolution of blood clots in the coronary arteries), coronary angioplasty (balloon dilatation of a narrowed coronary artery) and heart biopsy.
Procedure
Heart catheterization is usually performed in the hospital by cardiologists (heart specialists). Although the patient is awake for the catheterization, a sedating medication like Valium is given just prior to the procedure. The cardiologist may choose to insert the catheter into the blood vessels on the inside of the elbow or in the groin. In order for each side of the heart to be tested, the artery and vein must be entered separately.
After a local anesthetic is injected, a small (one inch) incision is made to locate the desired artery and vein. Alternatively, the vessels can be entered by direct puncture through the skin. The catheter, a plastic tube less than a quarter of an inch in diameter, is then inserted into the vessel and advanced toward the heart under the guidance of fluoroscopic X-rays. It is pushed, pulled and twisted into the proper position for pressure measurements and injection of the dye. The patient feels very little discomfort, except for perhaps, a feeling of warmth and nausea when the dye is injected. A "cath." takes about an hour.
Afterwards, pressure is applied to the puncture sites to minimize bleeding and the patient is observed.
Complications
Heart attack (.07%), stroke (.07%), blood clot formation in the artery and vein, injury to the heart and blood vessels, abnormal heart rhythms, hazards from electrical equipment, bleeding and infection are the major complications. Death occurs in about one out of 700 procedures.
Alternatives
Although catheterization is the best method of demonstrating the anatomy of the coronary arteries prior to heart bypass surgery, there is a great deal of controversy surrounding the selection of patients to have it done. The treating physician must take into account the patient's history of heart disease, symptoms, electrocardiogram (EKG) and treadmill test, as well as whether similar information could be obtained from various heart scans.
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