Coronary angiography is little short of miraculous

Q. My doctor suspects I have heart disease and wants me to have an angiogram. What will happen during this procedure?

A. Coronary angiography is the gold standard for diagnosing coronary artery disease, a narrowing of the coronary arteries that reduces blood flow to the heart.

The miracle of coronary angiography is that the doctor can see not just inside your heart but also inside the arteries that feed your heart — without ever cutting the skin of your chest. But before answering your question, let me give you a little medical history. How did this miracle happen?

Four hundred years ago, the English physician William Harvey described how the heart pumps blood throughout the body to all the tissues through arteries, and then the blood returns to the heart through veins. Each artery is like a highway leading from the heart to somewhere else in the body.

In the 1940s, two scientists followed up on a simple idea that was a century old: Any highway leading from the heart to, say, a leg or an arm is simultaneously a highway leading from the leg or arm back to the heart.

They inserted thin, soft tubes (catheters) into an artery in the leg and pushed “backward” up the artery until the tip of the catheter entered the heart. Pressure measurements and pictures could be taken inside the chambers of the heart. That discovery was honored with the Nobel Prize.

Then in the 1960s, doctors at the Cleveland Clinic extended that advance by showing that the same catheter could inject dye into the coronary arteries. (I've put an illustration of this on my website, AskDoctorK.com.)

Now to your question about what will happen. First, if you are allergic to X-ray dye, tell your doctor. He or she may need to use an X-ray dye that is less likely to trigger allergies, or you may take medication to reduce the likelihood of an allergic reaction.

A nurse will clean and shave the area of your arm or leg where the catheter will be inserted. You will lie on a flat table under a large X-ray machine and be given medication to help you to relax. An intravenous (IV) line is inserted into a vein in your arm to deliver fluids and medications.

The doctor will numb your skin and make a small cut to reach a large blood vessel under the skin surface. The doctor will insert the catheter into the blood vessel and move it toward your heart. The procedure usually takes less than an hour and should not be painful.

Once the test is finished, the catheter will be removed and the insertion site closed with stitches. You will stay in bed for several hours while a nurse monitors your vital signs. The nurse also checks for bleeding and monitors the pulse, color and temperature of the arm or leg in which the catheter was inserted.

If a blockage is found by the angiogram, an angioplasty and stent may be performed to open the blockage.

Ÿ Dr. Komaroff is a physician and professor at Harvard Medical School. Submit questions or get additional information at AskDoctorK.com.