Ihnken, MD, clinical assistant professor of cardiothoracic surgery at the Stanford University School of Medicine, was using an innovative technique called "beating-heart" surgery for coronary bypass. It replaces the more conventional use of a heart-lung machine, which allows for stopping the heart during surgery.
"It's very, very technically demanding," said Ihnken discussing the challenge of working on a still-beating heart shortly before he stepped into surgery to do so. "Surgeons don't want to put up with the stress. But it's so beneficial for the patient."
Despite its reputation as a technically tricky procedure, beating-heart surgery has garnered renewed attention recently as the trend toward less-invasive methods of heart surgery grows stronger.
"We need to be researching this," said Robert Robbins, MD, chair of the cardiothoracic surgery department at the School of Medicine, who hired Ihnken this summer to lead investigations into the potential benefits of less-invasive surgeries such as beating-heart and robotic heart surgery. "We need to make it available to our patients."
Currently, most heart surgeons use the more conventional method of putting a patient on a heart-lung machine, aka "the pump," for bypass surgeries. The pump lets the surgeon stop the heart by keeping blood circulating throughout the body, which keeps the patient alive, while the doctor sews on new vessels. It's easier for surgeons to perform because they have a stable target. The heart is not moving.
In beating-heart surgeries - currentl y used in about 22 percent of U.S. bypass procedures - a surgeon's ability to stitch vessels onto a moving, blood-filled heart replaces the need for the heart-lung machine. A stabilizer, a small device with a suction cup attached, is used to minimize the motion of the heart where the stitching is done.
The hesitancy of most surgeons to switch to beating-heart surgery is, in part, due to the overall success of the heart-lung machine over the past 40 years. In other words, if it ain't broke, why fix it?
But proponents of beating-heart surgery, such as Ihnken, point to the risks associated with conventional bypass surgery, including blood loss, stroke and kidney failure. Because the body doesn't have the added stress of being put on a heart-lung machine, beating-heart surgery can reduce these risks, and does so particularly well among such high-risk groups as the elderly and, surprisingly, women, Ihnken said.
"For reasons not well-understood, women don't do as well during bypass as men," Ihnken said. "Women have double the mortality rates following bypass."
Besides his own positive experiences with the technique, Ihnken points to a recent report in the new journal Innovations, which presents an analysis by an international group of doctors of more than 150 previous studies of the procedure. It found that the beating-heart technique is as safe as conventional heart surgery, with fewer complications and lower costs. The consensus report, based on randomized controlled trials and retrospective studies, concluded that when complications such as blood loss, stroke, kidney failure and irregular heart beats were considered, beating-heart surgery had a definite advantage over conventional bypass.
"Beating-heart surgery is an advance in cardiac surgery because it provides a better result for patients," said John Puskas, chief of cardiothoracic surgery at Emory Crawford Long Hospital, Atlanta, and one of the 12 authors of the paper.
Still, scientific evidence does not yet conclusively show its benefits, said Robbins, addding that he wants to see more research done before he's convinced.
"It's just so difficult," explained Robbins, who first used the procedure when it was developed a decade ago and now uses it only occasionally. "I don't have the time to devote to it. You need to do it often to be good at it."
Which is exactly what Ihnken plans to do. He's completed more than 130 of the surgeries and does all his bypass work off-pump. "I really want to build Stanford as an off-pump center," he said, before scrubbing up for surgery on that afternoon earlier this year. "I want patients sent here from everywhere."
Ihnken would spend the next three-and-a-half hours intricately stitching new blood vessels onto the beating heart of his patient. When he lifted the heart out of the chest, a tricky step in the beating-heart procedure, the doctors and nurses and technologists in the room turned suddenly quiet. The beat, beat, beat of the heart monitor filled the air. Ihnken, head tilted, found the spot he was searching for on the heart's backside and, finally, looked up.
"Everything OK out there?" Ihnken asked the anesthesiologist breaking the tense silence.
"Really stable, really stable," the anesthesiologist answered. "He's tolerating it really, really well."