Valve-in-Valve TAVR Results Encouraging

For patients with degenerating bioprosthetic valves who are at extreme risk for open surgical replacement, valve-in-valve (ViV) transcatheter aortic valve replacement (TAVR) is a lifesaving option, says E. Murat Tuzcu, MD, a Cleveland Clinic cardiologist experienced in the procedure. Although ViV TAVR is still considered investigational in the United States, results reported to date are encouraging.

“ViV TAVR can make a life-or-death difference for patients who need a new valve, but who are at very high risk for standard open heart surgery. They should be offered the opportunity to participate in clinical studies,” he says.

At the American College of Cardiology 2014 Scientific Sessions, Dr. Tuzcu and colleagues from the STS/ACC Transcatheter Valve Registry presented an overview of the ViV TAVR experience in the U.S using the first-generation, balloon-expandable, Edwards’ Sapien valve. Of the 201 patients entered into the registry who had undergone ViV TAVR from November 2011 to November 2013 in 250 US centers, the in-hospital mortality rate was 4.0 percent—substantially lower than the STS-predicted perioperative mortality risk of 8.0 percent. In-hospital complications included stroke (2.5 percent), major vascular complications (5.0 percent), major bleeding (3.6 percent) and need for first-time pacemaker (3.5 percent).

“ViV TAVR was an effective treatment for severely degenerated, surgically placed aortic prostheses. Post-TAVR echocardiography demonstrated moderate or severe paravalvular aortic regurgitation in only 2.8 percent, which is considerably less than the rate seen after TAVR for native aortic stenosis,” says Dr. Tuzcu. “The average gradient across the new valve was slightly higher than the gradient usually seen after TAVR procedures done in native valves.”

Higher gradients were seen more often in patients who had surgically placed valves of 21 mm or less.

Global experience

The international experience with ViV TAVR was summed up in an article published in the Journal of the American Medical Association on July 9, 2014. The review, which included 459 patients in 55 medical centers outside the U.S., found high rates of survival and low rates of complications.

In this cohort of very sick patients, the mortality rate was 10 percent at 30 days and 17.0 percent at one year. The rate of major stroke at 30 days was 1.7 percent. Importantly, patients experienced significantly improved function, moving from NYHA class 4 to NYHA class 1 or 2.

Predictors of success

In both the U.S. and international experience, several factors influenced outcomes.

Patients with surgical valves smaller than 21 mm fared worse than those with larger valves. With an aging population and the limited durability of bioprosthetic valves, the likelihood of needing a surgical valve replacement is growing. Dr. Tuzcu suggests surgeons may want to think ahead.

“Put in as large a valve as possible. In patients with a small aortic annulus, consider root enlargement, since a small size produces a smaller gradient,” he says. “The smaller the valve, the smaller the gain that is achieved with ViV TAVR, and the potential for worse outcomes.

The underlying cause for symptoms—stenosis or regurgitation—also plays a role. In the U.S. as well as global experience, patients with predominately leaky, degenerated, surgically placed valves appeared to fare better than those with stenosed valves. “Those with stenotic valves appeared to have more deaths and strokes,” says Dr. Tuzcu.

Summing it up

With only about seven years’ experience in ViV TAVR, researchers are excited, but cautiously optimistic.

“We have reached a fundamental understanding about certain core issues: We are confident that ViV TAVR is safe and feasible. For high-risk patients, it is very promising. For extreme-risk patients, it is a lifesaver,” says Dr. Tuzcu.

“We also know that outcomes are generally better in patients with larger valves. When the surgical valve is small in size, at this time a self-expanding, supravalvular TAVR device may be better suited for the patient,” he says.

How ViV TAVR outcomes compare to those of standard surgical treatment in high- risk and intermediate-risk but operable patients remains unknown. Further studies will answer this question.