Remote stent surgery safer, easier for MD

The procedure is called an angioplasty; sometimes, doctors will finish by inserting a stent — a miniature, tube-shaped cage — into the artery, to keep the pathway open for blood flow.

The patient lies sedated, but conscious. An X-ray machine is continually taking pictures, giving doctors a real-time picture of the wires and catheters as they progress through zig-zagging arteries.

The patient will do this only once, but the doctor may perform many such procedures. To avoid exposure to the X-rays, he or she will wear a lead apron, vest, and collar weighing as much as 40 pounds. It’s uncomfortable enough to be a real burden, especially during such time-consuming, exacting work.

Corindus Vascular Robotics, based in Natick, has developed an experimental system to allow surgeons to perform angioplasties by remote control.

The doctor sits a short distance away from the patient, in a radiation-proof cockpit, and uses a video-game-like console to control a robot that can navigate through blood vessels. The CorPath 200 System could bring the working conditions of doctors up to date with other revolutionary advancements in their field, the advocates said.

“The first stent was first placed in 1986,’’ said Corindus’s chief executive, David Handler. “There are all of sorts of new stents, new guide wires, new X-ray machines. But the procedure was still being done the same way it always had been.’’

It’s a delicate process.

Interventional cardiologists manipulate the wires and catheters the way a plumber extends a snake into a stopped-up drain, using both hands at once to torque and push or pull the wires and catheters. The difference is that for a doctor, a wrong move could damage the wall of a patient’s artery.

The lead gear used during angioplasties is “like you are wearing a camping backpack continuously,’’ said Dr. Douglas Drachman, an interventional cardiologist at Massachusetts General Hospital. Yet the procedure “requires finesse to advance the guide wire across a complex narrowing in an artery,’’ he said.

Almost half of physicians who perform angioplasties and similar procedures in lead apparel report spine problems, according to a survey cited in a 2009 issue of the journal Catheterization and Cardiovascular Interventions.

The same article warned that more studies are needed on the effects of radiation on interventional cardiologists, although doctors who regularly work with radiation are more likely to contract cancer.

The CorPath 200 is designed to bypass those troubles, said Handler. After a doctor inserts the initial wires and catheters necessary to send the balloon and stent into the patient’s artery, he attaches a robotic arm to the lines. The doctor then moves to the cockpit a few feet away, and without needing the lead gear, finishes the job using two joysticks. The cockpit has screens above the console that show the X-ray images and other vital signs.

“It’s just like flying a plane,’’ said Dr. Joseph Carrozza, chief of cardiovascular medicine at St. Elizabeth’s Medical Center. “We’re putting the doctor in a better ergonomic position, where he or she can access information much easier.’’

Carrozza is overseeing clinical trials of the CorPath 200 before Corindus applies for Food and Drug Administration approval to market the system. The device has been successfully tested on people in the United States and abroad, Handler said. Doctors remain close to the patient in case complications arise, he said.

Dr. Daniel Fisher, director of interventional cardiology at UMass Memorial Medical Center in Worcester, said he used an early version of the machine a few years ago during a test at Corindus. He liked how the company was trying to make his job easier, and he was eager to see the results of the trials. But he remained skeptical the machine could replace his experienced hands.

“We’re used to the tactile feeling of hardware within the patient’s body and coronary artery and other vessels,’’ he said. “The more sensory input you have probably provides you with more checks and balances to guide you through the procedure.’’

Obviously the machine more directly benefits the doctors than the patients, Carrozza said. But in reducing the effort physicians expend remaining upright in the lead equipment, patients would benefit — as long as trials demonstrate that angioplasties can be completed as safely and effectively as with the current approach.

“By the time you are doing your fourth, fifth, or sixth case, you really feel as if you’ve taken a beating,’’ Carrozza said.

“Most interventional cardiologists will tell you they are not as sharp, they’re not as fresh, at the end of the day. [The machine] is not comfort for the sake of comfort. It’s comfort for the sake of being able to focus on the patient.’’