Portable driver liberates artificial-heart patient
Seven weeks post-implant, Chris Marshall had walked 156 miles, demonstrating the value of a new surgical option at UW Medical Center.
The case gave UW Medicine’s Regional Heart Center footing in an elite cadre of U.S. cardiac programs that offer a surgical option to patients who otherwise would be managed medically or referred to hospice.
“We have a viable option for patients with biventricular failure that we didn't have before. People with heart failure who also have biventricular failure are good candidates for this,” said Dr. Nahush Mokadam, a surgeon and UWMC’s co-director of heart transplantation.
The heart device is made by SynCardia Systems and approved for use as a bridge to transplant in the United States, Canada and Europe.
During surgery, a patient’s failing ventricles and four heart valves are removed. Two bulbous polyurethane chambers, acting as ventricles, are sutured to the remaining heart structure. Each chamber has an in-flow and out-flow valve and a four-layer diaphragm but no sensors, motors or electronics.
It is powered by a pneumatic driver outside of the patient’s body, which is connected by two tubes that exit the patient’s abdominal wall. The driver supplies vacuum pressure to pull the diaphragm to the bottom of the ventricle, allowing blood to enter, then produces a precisely calibrated pulse of air that pushes the diaphragm to the top of the ventricle to fully eject the blood.
Initially patients’ devices are tethered to “Big Blue,” a 400-pound, refrigerator-sized driver. SynCardia also makes a 14-pound, portable “Freedom” driver, which is in clinical trial to determine whether it is as effective as Big Blue for postoperative patients who are stable.
UWMC is one of just 13 test sites nationally that, as of April 9, were managing one or more patients on the portable driver. It is battery-powered, rechargeable and can be carried in a backpack, shoulder bag or rolling caddy.
“Not only do we have the device, we also have the ability to discharge these patients, so they don't remain prisoners in the hospital. That’s the distinction here,” Mokadam said.
The artificial-heart patient, Chris Marshall, 51, of Wasilla, Alaska, was admitted to UWMC in January with idiopathic cardiomyopathy and episodic ventricular tachycardia. The decade-old diagnosis had left his heart precariously weak. Dr. Daniel Fishbein, UW professor of medicine, managed Marshall’s health until the implant in March.
An avid hiker, Marshall’s health is otherwise good, and this has aided his recovery, Mokadam said. In the seven weeks after his March 21discharge, Marshall walked 156 miles, powered by the portable driver.
“It helped that his heart failure was isolated and that he was in otherwise good shape. That is a factor of getting a good outcome: getting patients before they become chronically ill or so chronically ill that we can't catch up with their other organs that are no longer working,” he said.
UW Medicine cardiac surgeons will place devices in upward of 100 patients this year, he projected, employing ventricular-assist mechanisms, defibrillators and the SynCardia heart. Implants are performed in chronic, acute and emergent circumstances.
During the 10-year clinical study of the Total Artificial Heart that led to its FDA approval in 2004, 79 percent of patients survived until transplant. The device has been implanted in more than 1,000 people worldwide. The current longest-supported patient received a transplant after 1,374 days with the device.
On May 9, 2012, nearly 3,200 Americans awaited a heart transplant, including 93 in Pacific Northwest states, according to the U.S. Organ Procurement and Transplantation Network.
To refer a patient or learn more, contact the UW Medicine Regional Heart Center at 866.UWHEART (894.3278).
University of Washington Medical Center (UWMC) in March became the first Pacific Northwest hospital to discharge a patient implanted with the Total Artificial Heart, the world’s only such approved device.
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