Heart-lung machine aids artery-clearing technique

November 14, 1990|By Jonathan Bor

People with advanced heart disease who were once considered too sick to withstand conventional treatments can benefit from a popular "balloon" technique if they are temporarily kept alive by a heart-lung machine, a University of Maryland cardiologist reports today.

For several years, doctors have used an inflatable balloon to spread apart the obstructions that often clog the coronary arteries and make it difficult for the organ to pump blood through the body.

The technique, called balloon angioplasty, is considered too risky for some patients whose hearts are so diseased they could die while the procedure is in progress.

But Dr. Robert A. Vogel, chief of cardiology at the University of Maryland Hospital, said a two-year study offers evidence that angioplasty is safe and effective for these patients if they are simultaneously supported by a heart-lung machine. The device gives the heart and lungs a rest during angioplasty by mechanically pumping the body's blood and infusing it with oxygen.

"It really comes down to this: You can safely do angioplasty in the most high-risk patients," Dr. Vogel said in an interview. He is scheduled to present results of the study today at the annual conference of the American Heart Association being held in Dallas.

Patients tethered to a heart-lung machine remain fully conscious and often talk with the medical team while the procedure is being done. During this time, their hearts pump weakly or stop beating altogether.

Dr. Vogel estimated that 15,000 to 20,000 high-risk patients in this country every year could have angioplasty with a heart-lung machine at least on standby -- although many of the patients probably would not need to be connected to the machine.

In the study, researchers found 85 percent of the 455 patients who underwent "supported angioplasty" -- the balloon technique coupled with the heart-lung machine -- were still alive two years after the procedure. "These patients have really done very well -- they have a lot less angina or chest pain, and they have considerably better pumping action of their hearts," he said.

The study, coordinated by the University of Maryland, involved 23 hospitals across the country. Patients had their surgery in 1988. In Maryland, University Hospital first introduced the technique in 1987.

While the study did not involve a control group, Dr. Vogel estimated that 70 percent of high-risk patients whose blockages are left alone can be expected to survive two years.

Candidates for the procedure are patients whose hearts pump weakly and those who have total blockages in two of the three major coronary arteries and a partial blockage in the third. In the latter group, using a balloon to open the partially blocked artery could temporarily cut off all blood flow and prove fatal; the heart-lung machine, however, keeps the patient alive by bypassing the heart while the artery is being opened.

Many patients in the study group had previous bypass operations, but were turned down for another because their arteries were too small to accept a graft. In a bypass operation, surgeons divert blood flow around the blockage by stitching a synthetic loop onto the artery.

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