Cardiology Researchers Seek Low-Risk Subjects for Transcatheter Aortic Valve Replacement Trials

A team of cardiology researchers led by Eduardo J. de Marchena, M.D., professor of medicine and surgery at the University of Miami Miller School of Medicine, is seeking low-risk subjects for the next phase of an ongoing series of trials comparing the outcomes of transcatheter aortic valve replacement (TAVR) versus conventional open-heart surgery. In prior trials with high-risk and intermediate-risk patients, TAVR produced equivalent or superior patient outcomes.

TAVR surgery involves the placement of a medical device into the damaged heart valve using a catheter inserted into an artery in the groin or leg. The interventional cardiologist then implants the device, which takes over the task of pumping blood through the valve.

Approximately 85,000 aortic valve replacement procedures are performed in the U.S. each year. The most common cause is aortic stenosis, an acquired condition usually found in elderly patients in which scarring or calcium buildup narrows the valve and restricts blood flow from the heart to the aorta, and from there to the rest of the body. An estimated 1.5 million Americans suffer from aortic stenosis; 500,000 (half of whom are undiagnosed) have a severe form that has a high risk of death within two years without valve replacement.

Before TAVR, the challenge — especially with patients who may be in their 80s or 90s — was that the risk of perioperative complications or death was too high for conventional surgical valve replacement to be considered, said de Marchena, who is also Associate Dean for International Medicine and Director of the International Structural Heart Disease Training Program.

“That started to change in 2010, when the first TAVR trials began in the U.S., including here at the University of Miami,” de Marchena said. “In the trials with the high-risk subset, half received the transcatheter valve, and half had surgery. The results showed near equivalency between the two procedures.”

De Marchena points to Bruce Kirsch, one of the subjects in the high-risk trials, as an example of the patients who have had positive results with the less-invasive TAVR procedure. Kirsch, a retired businessman in his early 60s, had a conventional open-heart surgical valve replacement in 2006. Over time, the valve began to function poorly, leaving him as chronically fatigued and short of breath as he had been before the surgery. Because of his prior surgery, and the unrelated liver disease that forced him into retirement, Kirsch was a poor candidate for a repeat open-heart procedure. Accepted into the Miller School trial, he had the TAVR procedure in November of 2014 — an experience that was “life-changing,” he said.

“It was like night and day after the TAVR procedure,” Kirsch said. “I entered the hospital on November 6, and the procedure was done that day. I remained in the hospital the next day, and on the third day I went home. I felt like a new man. By comparison, after my open-heart surgery, I was in the hospital for two weeks. All I can say is thank you to Dr. de Marchena and his amazing team.”

De Marchena said the results of trials with intermediate-risk patients — who tend to be younger and healthier than the high-risk subset — are even better.

“Our trial is currently active, but others are completed, and the transcatheter valve procedure has proved to be superior to surgery,” he said. “Now we’re moving to a trial with the low-risk group — those patients who, in the past, would have automatically been sent to surgery. We need to know if the added complexity and discomfort of surgery conveys better outcomes than the less invasive TAVR procedure.”

The unknown, said de Marchena, is what will happen over time. The average life of a replacement valve is 10 to 15 years. A younger patient might need two or three additional replacements in the course of his or her lifetime.

“Fortunately, for a failed valve, we can generally insert a new transcatheter valve inside the failing tissue valve,” he said. “Our progress has been amazing. The technology has evolved through clinical trials to get us to a point where we can randomize trials with low-risk patients and compare a surgical procedure with a transcatheter valve. That was inconceivable 10 or 15 years ago.”

De Marchena is the principal investigator in the upcoming trial. The co-investigator is Tomas Salerno, M.D. Other members of the research team include Anthony Panos, M.D., Carlos Alfonso, M.D., Donald Williams, M.D., Christian Marin y Kall, M.D., Ximena Marincic-Sanchez, M.P.H., and Suresh Atapattu, M.S.

For more information on the upcoming trial, call 305-243-9200.

Tags: aortic stenosis, cardiology, clinical trials, transcatheter aortic valve replacement