Twenty-one-year-old Frederick Anderson went home to Kalamazoo yesterday after spending three weeks recovering from a heart transplant made possible by an artificial heart.
The artificial pumping device preserved his life until a donor heart could be located. Anderson said the device was not too uncomfortable, but it felt a lot different than an ordinary heart.
"The pump was kind of loud," he said. "It shook my chest a lot - it was stronger than a heartbeat."
The artificial heart Anderson received, called Heartmate, is a pneumatically operated pumping device that is unique because it has a much lower risk of stroke - the heart carries a 2-percent risk while most traditional devices have a 30-percent to 40-percent risk.
The Heartmate kept Anderson alive for 40 days after it was implanted at the University Medical Center on Oct. 2.
"This is the first successful transplant using this particular device (in Michigan)," said Dr. Francis Pagani, who implanted the device and then performed the transplant surgery Nov. 12.
Nearly 800 Heartmates have been implanted throughout the world since the device became commercially available two years ago. About 40 institutions in the nation offer surgery using the device.
"It passed FDA regulations with the intent that it be used as a bridge for transplantation," Pagani said, noting that the longest a patient has survived with the device is two years. "But there is currently research being done exploring the possibility of using the device in lieu of a transplant."
Pagani said the Heartmate is a novel design that uses its rough surface in the pumping chamber to collect blood clots.
"Rather than a smooth surface, it is rough," he said. "One can envision it looking like sandpaper - the clots adhere to it and don't break off."
Pagani said the Heartmate's design is counterintuitive because blood vessels in the heart secrete a substance that prevents clots from forming on their walls, but by using the gathered clots, he said the Heartmate creates a smooth lining.
"The blood vessels in the heart have a smooth lining Ñ they make a substance that prevents clots along the walls," he said. "We try to mimic this with the device."
Victor Poirier, president of ThermoCardiosystems of Woburn, Mass., the company that manufactures the heart, said the Heartmate is unlike any other artificial heart currently available, and that its reduced stroke rate derives from its design.
"The reduction in stroke rate is a result of many factors such as the pump design and the valves, but the primary factor is the surface of the tubes Ñ it has a very rough surface," Poirier said.
"When blood flows through the tubes, blood cells and proteins are trapped on the surface and form a lining that converts, over time, to a material much like that found in arteries and veins," he said.
Poirier said the Heartmate anchors the lining and allows surface growth.
"In a nutshell, we grow a living biological lining on the interior of the device to make it more compatible with the patient," he said.
Anderson suffered from a degenerative heart disease known as idiopathic cardiomyopathy, in which the heart muscle beats more rapidly but less vigorously as it deteriorates.
"It was a machine that basically pushed air into a pump that was connected to my aorta," Anderson said. "From there it pushed blood throughout my body."
Poirier said he expects the number of Heartmate implants to increase significantly in coming years and estimated that between 1,000 and 1,200 implants of the device will occur next year alone.
The Heartmate Anderson received was a temporary device to sustain him until his transplant surgery, but Poirier said a new version of the Heartmate, which is currently being researched, is intended to be a permanent substitute for the human heart and will be available for patients in two to three years.
"We're doing clinical studies for permanent use," he said. "It's similar to the old model, but with electric batteries instead of an air pump. It's undergoing trials for use as an alternative to transplants."