The Moviemakers

Nearly three out of four Americans suffer from some degree of artery disease, but those who finally learn of their illness usually do so the hard way--with a heart attack or a stroke. And because doctors have been unable to look into the body and watch the small coronary arteries work, they have also been unable to pinpoint blockages and accurately determine the extent of artery disease.

Arteriograms (Xray still photos of arteries that have been flooded with radiopaque dye) help, but they are not always reliable: the "flooding" technique often fails to fill the arteries with enough dye, and still pictures do not clearly separate small vessels that are superimposed on each other. One of the major breakthroughs at last week's AHA meeting came when the Cleveland Clinic's Drs. Earl Shirey and F. Mason Sones Jr. demonstrated a diagnostic technique that seems likely to improve on the arteriogram--a method of coordinating the ray, a specially designed catheter and a movie camera to produce the first high-peed (60 frames per second) pictures of he coronary arteries in action.

Simple Dexterity. Prime element in he Sones-Shirey method is the catheter, a snakelike, 31-in. tube that tapers in diameter from 3.2 mm. down to 1.6 mm. at its tip. The catheter is first inserted in the patient's brachial artery, inside the elbow of the right arm, and maneuvered up the arm into the chest, until its passage is stopped by the aortic valve, directly above the heart. Except for a dull ache in the elbow (local anesthesia is administered) the operation is painless Because the arterial nerves are insensitive to the catheter's presence.

Monitoring the operation through an image intensifier--a refined fluoroscope that produces an X-ray image 1,500 times Drighter than the old-style fluoroscopic screen--Drs. Sones and Shirey then release a tiny amount of radiopaque dye through the catheter into the aorta in order to locate the spot at which right and left coronary arteries join the circulation's main stem. "The rest," says Sones, 'requires only a little bit of simple dexterity." The catheter is successively slipped into both coronary arteries, and small injections of dye (2 cc. to 5 cc.) are sufficient to silhouette the arteries' full course for the benefit of a movie camera attached to the image intensifier.

Half a Toothpick. With high-speed film, the resultant X-ray image is sharp enough to show blockages only one-fourth the width of a coronary artery, and to pick out collateral blood vessels only 80 microns in diameter--about half the thickness of a toothpick. Says Sones: "We hope eventually to be able to see vessels as small as 30 microns (.0012 in.) in diameter, because even vessels that small can act as effective collateral channels for blood from a diseased artery."

Dr. Sones admits that his technique involves some risk. Although the catheter is less than half as thick as an average coronary artery, it can still obstruct the flow of blood into the heart. Throughout the operation, Drs. Sones and Shirey monitor the pressure of the blood against the catheter's tip. Explains Sones: "If the pressure starts to flatten out, we know the tip has obstructed the artery or one of its branches. Then we have from ten to 30 seconds to get it out before the heart is starved for blood and the patient has a heart attack." The mortality rate so far: two deaths in 526 examinations.

Despite its risks, the technique will be welcomed, says Dr. Sones, if it proves to offer physicians a precise method of diagnosing coronary artery disease.

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