Lasers Offer Hope for Worst Heart Ailments : Health: In experimental surgery, holes are burned through muscle walls to provide oxygen. Treatment may be an alternative when angioplasty and bypasses fail.
An unusual new procedure using a high-powered laser to literally blast holes in the heart is providing hope for patients with severe coronary artery disease who have had bypass surgery and have no other treatment options, researchers reported Saturday.
Pioneered by surgeons at the San Francisco Heart Institute, the technique punctures holes in the heart wall that allow blood to enter capillaries in the muscle, providing oxygen and nutrients to tissues that have been starved by blocked arteries.
The procedure has reduced pain in 91% of the 46 patients who have received it in a clinical trial and has increased mobility in 76%, surgeons reported at a meeting of the Society for Thoracic Surgery in New Orleans.
The laser procedure represents a radical departure from the conventional methods of treating coronary artery disease. “This is a totally revolutionary way to get blood supply to heart muscle,” said Dr. Lawrence H. Cohn of Harvard Medical School, chairman of the department of thoracic surgery at Brigham and Women’s Hospital in Boston.
But proponents are not yet touting the procedure, called transmyocardial revascularization, as an alternative to bypasses or angioplasty. Rather--at least until enough data is accumulated to assess the procedure’s long-term effectiveness--they say it is a last resort for patients for whom all other treatments have failed.
Nonetheless, proponents say the procedure is significantly cheaper and easier to perform than bypass surgery, and preliminary evidence suggests that its beneficial effects may persist longer because--unlike grafted arteries--the laser holes do not seem to plug up again. But surgeons note that it has not worked for everybody who has received the procedure, and they are not sure why. Four patients died of complications from the surgery.
Coronary artery disease is the leading cause of death in the United States. More than 400,000 coronary artery bypasses are performed in this country each year, in which a vein, typically from the leg, reroutes blood around the blockage. Surgeons also perform almost that many angioplasties, in which a balloon is inflated inside an artery to compress blockages and restore blood flow.
But tens of thousands of patients who have undergone such therapies and suffered relapses have arteries that are too fragile for further treatment. The new approach could be their only salvation, some surgeons said.
“We are trying to be very conservative and assess the results from this technique objectively, but we are really quite encouraged,” said noted heart surgeon Dr. Denton Cooley of the Texas Heart Institute, who has treated 12 patients.
“This sounded far-fetched when we were first approached to participate in trials,” Cohn said. “But now that we have done eight patients, it’s proved extremely interesting and makes us somewhat optimistic that this will have a place for treatment of patients who have no other recourse.”
“We need to see confirmation of their results, but this is really the cutting edge of heart surgery,” said Dr. George Sopko of the National Heart, Lung and Blood Institute. “I would like to see a little more animal research, however, to explain how it works.”
Erroll Taylor, an 86-year-old retired butcher, was the first person to undergo the procedure, in San Francisco in January, 1990. Taylor had had two bypass operations, the first at age 67, as well as angioplasty. But since 1977, he had been in virtually constant pain as his heart muscles screamed for oxygen.
“The pains were terrible. There is no way I can describe what those pains were like,” Taylor said in an interview. “When they hit me, I was virtually helpless.”
He was housebound for 13 years, checking into the hospital frequently to receive injections of a blood thinner that reduced the pain somewhat.
Within a month of his operation, Taylor said, “my life was back to normal.” He is able to walk comfortably around the neighborhood, go fishing and enter fly-casting contests, his favorite pastime. “I’ve even won a couple of medals since the operation,” he said.
Although the technique may appear to be a radical departure, its developers note that its roots lie in a natural phenomenon observed in reptiles. Researchers have long known that reptile hearts receive a substantial proportion of their nourishment through similar, naturally occurring channels into the heart muscle.
Scientists have been attempting to reproduce the channels since the 1930s, using needles, catheters and other devices to puncture the tissues, but the trauma always made the holes heal closed.
The groundwork for the current studies was laid by Dr. Mahmood Mihroseini of St. Luke’s Medical Center in Milwaukee, who spent more than 20 years studying the use of lasers in animals. The high-powered lasers vaporize cells in their path, creating a clean hole without any trauma to adjacent cells. The animal studies show that the channels remain open indefinitely--which leads surgeons to hope that they will also remain unplugged in humans.
Dr. John R. Crew of the San Francisco Heart Institute performed the first 15 procedures in humans with a laser developed by PLC Systems Inc., the Massachusetts company that manufactures the $350,000 laser system.
Unlike a bypass operation, in which the heart must be stopped, the new procedure is performed while it is beating. A computer attached to the heart by electrodes fires the laser’s 0.05-second pulses between heartbeats so that the laser does not interfere with the electrical currents that control heart function.
The pulse must also be fired while the heart is full of blood. After the beam burns through the tissue, the rest of its energy is absorbed by blood, preventing further damage to surrounding heart tissue.
Surgeons punch 20 to 35 holes, each a fraction of an inch in diameter, in the area of the heart that needs nourishment. Although blood immediately begins leaking from the holes, clots quickly form on the surface, blocking further blood loss. The rest of the channel remains open, allowing blood to be forced into capillaries.
Because the entire procedure is performed through a four-inch incision in the lower chest, it is much less invasive than a bypass operation. It costs about $15,000 to $16,000, compared to an average of $43,000 for a bypass, and the average hospital stay is about a week.
