New UCH heart failure specialist takes the pulse of LVADs

William Cornwell, MD, plans to examine the possible unintended effects of the powerful pumps that help patients with failing hearts
Aug. 30, 2016

With the recent addition of William Cornwell, MD, University of Colorado Hospital has expanded its team of advanced heart failure specialists, already the largest in the state. In addition to bolstering the team’s clinical and educational expertise, Cornwell brings a strong interest in a promising new avenue of research for both UCH and UCHealth.

Cornwell, 34, recently completed a five-year advanced heart failure fellowship at University of Texas Southwestern Medical Center in Dallas. During his time there, he specialized in cardiac transplantation and in left ventricular assist devices (LVADs), the mechanical circulatory support systems that play a crucial role in meeting what he called “the enormous unmet need” of patients with failing hearts.

William Cornwell, MD, joined UCH’s team of advanced heart failure specialists in July. He plans to study the effects of exercise on heart failure patients equipped with LVADs.

His work led Cornwell to ponder a surprising potential downside of LVADs. He observed that the devices are designed to restore cardiac output to normal levels in patients with failing hearts. They are capable of pumping up to 10 liters of oxygenated blood to the body. Yet he saw that some patients with LVADs still had symptoms of heart failure and struggled with everyday activities.

Paying at the pump

If the LVAD successfully does the job of a healthy heart, why should patients still have problems? One possible answer, Cornwell said, is that an LVAD leaves a patient without a defining feature of a real heart: a pulse.

Literature shows that the lack of a pulse “can have subtle implications on the body,” Cornwell said. These include changes in the structure of blood vessels that may increase the risk of strokes and gastrointestinal bleeding in LVAD patients.

It’s a surprising problem for heart failure specialists and other clinicians to be facing in 2016, Cornwell said. While other cardiac devices, such as defibrillators and pacemakers, respond to changes in heart rate during times of rest and exertion, even the most advanced LVADs “are just pumps,” he said. “They can’t account for needed increases in blood flow. They don’t really talk to the heart.”

The building blocks are in place for Cornwell and his colleagues at UCH to deepen understanding of the chronic effects of pulseless blood flow in patients with LVADs. Cornwell has a five-year grant from the National Institutes of Health to study the effects of mechanical circulatory support devices on exercise capacity in heart failure patients. He’ll have a research lab in the Clinical and Translational Research Center on the 12th floor of Anschutz Inpatient Pavilion 1 for that purpose.

Heart of the matter

He’ll also collaborate with Amrut Ambardekar, MD, medical director of the Cardiac Transplant Program at UCH and a cardiovascular disease specialist with the CU School of Medicine. Ambardekar has worked with bioengineers at CU to measure the properties of blood vessels in patients fitted with LVADs who receive heart transplants. They use tissue rings taken from aortic and pulmonary vessels in the patients’ damaged hearts, which otherwise would be discarded after transplant.

The salvaged material has yielded valuable information about changes in the vessels that might be linked to the LVADs and the banishment of a normal pulse, Ambardekar said. For example, elasticity tests of the artery rings show that the tissue from LVAD patients is often stiffer and less resilient than might be expected with normal aging. The tests have also revealed rapid increases in scarring of the vessels, Ambardekar said.

Cornwell is among the few clinicians nationally doing exercise studies on patients with LVADs, Ambardekar said. He believes the work will help to resolve some of the unanswered questions surrounding the long-term effects of the devices. It’s also part of a broader examination of the “unintended consequences of an engineering marvel,” as Ambardekar put it.

He noted that the original mechanical circulatory devices did generate a pulse in patients. But they were very large, difficult to handle, and not very durable. They generally broke down in 12 to 18 months, a testament to nature’s exquisite engineering.

“The heart is a very powerful machine,” Ambardekar said.

Revving up the research

The next generation of devices produced continuous flow, reducing the number of moving parts and increasingly their longevity many times over. But they eliminated the pulse, perhaps creating a new set of problems that the Heartmate 3, now in clinical trials at UCH and other institutions, attempts to address with so-called artificial pulse technology designed to imitate normal blood flow.

For Cornwell, the ideal solution would be a device that responds to changes in a patient’s activity and heart rate with the push of a button. He foresees working with cardiovascular specialists like Ambardekar, his heart failure colleagues, exercise physiologists, device manufacturers, bioengineers, and others interested in finding new treatment paths.

“There are any number of experts in their respective fields here that I want to learn from,” Cornwell said, citing as examples Michael Bristow, MD, who participated in studies in the late 1990s suggesting the effectiveness of beta blockers as therapy for class IV heart failure patients; and Wendy Kohrt, PhD, a leading researcher in exercise physiology and aging.

New endeavors

Colorado is the latest stop along a road that beckoned Cornwell long ago. “For as long as I can remember, I wanted to be physician,” he said. After earning his undergraduate degree in biochemistry at Ohio State University, he considered pursuing a PhD in that field, but decided in favor of his early aspiration and completed a residency in internal medicine at the University of Michigan.

With a desire to apply his scientific knowledge in the service of improving lives, heart failure seemed a field ripe with possibilities, Cornwell said.

“It’s an incredibly dynamic environment with very high highs and very low lows,” he said. He said he reminds himself that for each heart failure patient who survives to a successful transplant, there is a corresponding story of loss.

“We can tell someone who is on death’s door in a phone call, ‘There is a heart for you,’” Cornwell said. “But for that to happen, someone else had to die.”

He’ll spend the coming months caring for patients in the hospital and clinic, educating students and residents, and setting up the lab to conduct his research. In between, Cornwell said he plans to spend as much time outdoors as possible with wife Amanda and their three kids, ages 8, 6, and 1. They’ve already had their first mountain fishing excursion, he said.

He feels similarly settled in his professional choice. “As I look around, I see cardiology as a unique fusion of physiology and advanced technologies,” Cornwell said. “Where cardiology will go over the course of my career will be fascinating.”

About the author

Tyler Smith has been a health care writer, with a focus on hospitals, since 1996. He served as a writer and editor for the Marketing and Communications team at University of Colorado Hospital and UCHealth from 2007 to 2017. More recently, he has reported for and contributed stories to the University of Colorado School of Medicine, the Colorado School of Public Health and the Colorado Bioscience Association.