During his days at Oberlin, Billy Cohn '82 wanted to be a rock star. Today the Boston heart surgeon plays the bass guitar with his band, Shake, but his celebrity status is a result of his entrepreneurial work in the operating room, not his performances on the stage.
His invention, the Cohn Cardiac Stabilizer, has taken the field of cardiothoracic surgery to new heights. The simple device, fashioned in his basement from a set of soup spoons bought at the neighborhood grocery, allows surgeons to perform bypass surgery on a beating heart--a feat impossible until recently.
Bypass surgery is performed nearly 600,000 times a year, according to the American Heart Association. Traditionally, doctors stop the patient's heart by using a heart-lung machine that keeps the patient alive during the operation. The surgery involves splicing pieces of vein, taken from the leg, around the blockage in the coronary artery. Without the heart-lung machine, trying to carry out such a precise task would be like trying to do needlepoint while riding a horse.
For patients who qualify for bypass surgery, success rates are better than 90 percent. There remain, however, serious side effects that often result from the heart-lung machine itself. Some of the damage is caused by blood clots; patients may experience inflamed kidneys and lungs, and there is a small risk of damage to the retina of the eye.
Furthermore, even a small clot can damage the brain. A third to a half of patients who are put on the heart-lung machine may later exhibit cognitive defects, from memory problems and difficulty concentrating to depression and attention deficiency.
Until very recently, doctors had assumed that these side effects were the intrinsic risks of heart surgery--necessary evils that came along with the heart-lung machine. "That may still be true," Cohn says. "But if you can do an operation without the machine, and you can do it well, then it seems as though this would be a natural way for the field to move."
Wearing cowboy boots under his white lab coat and powder blue scrubs, Cohn doesn't fit the typical image of a surgeon. Give him an opportunity and he'll pull out a deck of cards and ask you to pick one, or make a handful of coins mysteriously jump from one hand to the other. In his Texas twang, he'll tell you how he just got one of his antique cars running again, or how he loves to fly-fish.
At Oberlin (where he dyed his hair black and white and played bass guitar), Cohn discovered performance art and says he did "all kinds of crazy things in the name of art." He remembers a time shortly after deciding on medical school when he and a friend set up a sign in Wilder Bowl that said "Do The Freak 'til You Drop with Young Professionals, 25 cents." For more than two hours they hung out on the grass doing The Freak--a popular 70s dance. "People would walk by and see us and join in," he chuckles. "At one point there was a line of 50 people doing The Freak."
The transition to heart surgery from performance art, sculpture, and music may seem strange for some, but Cohn claims that he's always had a passion for medicine. Growing up in Houston, one of the incubators of heart surgery, he often heard news of heart surgeon pioneers Michael DeBakey and Denton Cooley. He wasn't inclined toward academics in high school, but thought seriously about a medical career during his upper-level science classes in college.
Cohn studied at Baylor Medical School and joined the staff of Boston's Beth Israel Deaconess Medical Center and the faculty of Harvard Medical School in 1994. Two years later he visited Johns Hopkins University and watched as Dr. James Fonger used a new technique to operate on a beating heart without the heart-lung machine. A device that looked like a two-pronged salad fork was passed through a smallincision between the ribs; a stabilizer that Cohn said rode with the heart muscle "like a cowboy on a bronco." Impressed, he started using the method, but found its technical demands unsatisfying.
The Eureka Moment
Bypass surgery without the heart-lung machine is not a new concept; scientists have been looking for ways to get around its use for nearly a decade. But genius strikes when it's least expected. Cohn's "eureka" moment came while driving home from the hospital, when he convinced himself that there had to be a better tool than a salad fork. His vision was a device that would constrain the movement of the delicate coronary artery while allowing the heart to continue to beat around it. The surgeon, he predicted, could then construct the graft through a window cut out of the surface of the device. He drove straight to Stop & Shop and bought several soup spoons and, in his metal workshop (the same basement studio where he and his 7-year-old son built a propane-powered potato cannon), he worked through the night, hammering the spoons flat and cutting holes in their middles. He arrived at the hospital the next morning and headed for the animal lab. He tested the creation on pigs, dogs, and sheep, modifying the instrument as he went along. After several attempts, he was prepared to try his new device on a human patient.
In December 1996, a patient agreed to be operated upon with the homemade instrument. To Cohn's delight, the procedure worked beautifully. "There I was, in the operating room, trying it on the first human," he told a reporter. "And it was gorgeous." That first case was a single bypass, but Cohn has since used the device on patients with multiple blocked vessels. Today quintuple bypasses, using his stabilizer, are commonplace.
The following year the hospital sold his invention to Genzyme Surgical Products in Cambridge, which developed the mold for the commercial model. The prototype earned an enthusiastic response from test hospitals across the country. The final incarnation, constructed of metal and a plastic polymer, with adjustable settings and movable platforms, is far more high-tech than a spoon. More than 110 medical centers have purchased the device and more than 300 surgeons are trained to use it. Cohn estimates that more than 8,000 operations have been performed with the stabilizer.
Brian Cmolik, a surgeon at Case Western Reserve University School of Medicine, first tried the stabilizer in Boston, and reports that, so far, he is pleased with its ease. "You don't have to be God's gift to surgery," he explains. "The results are fairly easy to reproduce. This is a good product, and I appreciate the fact that Bill has been so honest with those of us who are learning to use it, so we don't repeat the mistakes he has already learned from."
Coincidentally, one of the pioneers of the heart-lung machine, Frederick Cross, is a 1942 Oberlin graduate. A member of the first generation of open-heart surgeons, Cross co-developed a heart-lung machine known as the Kay-Cross Rotating Disk Oxygenator, named after Cross and his co-inventor, Earle B. Kaye, which became one of the most widely used heart-lung machines in the world. At the time, in the mid-1950s, heart surgery was still at the forefront of medicine. Machines like Cross and Kaye's invention allowed surgeons to probe a living heart for extended periods of time by transferring the jobs of respiration and circulation from the patient's lungs and heart to a machine.
But beating-heart devices such as Cohn's stabilizer won't make the heart-lung machine obsolete, comments Cross. At this point, such apparatuses work best on select patients with strong blood vessels and a good cardiac output. For patients who don't fall into this category, he believes, the heart-lung machine is still the best option. "The modern era of surgery is changing the way we approach heart surgery," Cross says. "But it's not changing that fast."
Cohn says he gets a bad rap by some heart-lung machine proponents who are annoyed by his calling attention to some of the machine's negative side effects. "I think the heart-lung machine is an incredible device," he argues. "I use it all the time. But it is associated with potential side effects and complications that we'd love to avoid."
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