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New Uses for TAVR Growing Fast

Successes and advances point to a bright future for this nonsurgical valve-replacement technique.

If you haven't heard about a procedure called transcatheter aortic valve replacement (TAVR), it's only a matter of time before you will. This method of replacing the aortic valve through a catheter is rapidly fulfilling its potential by demonstrating its safety and efficacy in a wider number of patients with aortic stenosis.

Until TAVR, replacing a stiff, calcified aortic valve required open surgery. But many patients with aortic stenosis are elderly, and have medical conditions that make surgery risky or impossible. TAVR is a growing option for these patients.

The buzz about TAVR intensified when five-year results of the PARTNER study were presented at the American College of Cardiology Annual Meeting in April 2015. This important study compared TAVR with conventional treatments for aortic stenosis and followed patients for five years to see how they fared.

THE VIEW FROM DUKE

ANDREW WANG, MD, Structural Heart Disease Specialist, Duke

Improvements Will Lead to Increased Access
"Calcific aortic stenosis (AS) is a common heart valve lesion caused by similar risk factors as coronary artery disease. When AS becomes severe, symptoms of shortness of breath, chest discomfort, or near fainting occur, and average survival is reduced to two to three years unless aortic valve replacement is performed. Surgical valve replacement can safely be performed for most patients with AS, but some patients may have a higher risk of death or complications related to surgery due to other medical conditions. Transcatheter aortic valve replacement (TAVR) is currently approved for patients with symptoms of severe AS who have high or very high operative risk as assessed by a heart team of cardiologists and surgeons. There are two devices now approved in the U.S. for such patients based on the results of studies such as PARTNER. Improvements in the delivery catheters, valves, and the positioning mechanisms of TAVR devices have been moving ahead rapidly, and will lead to increased access to this treatment, lower procedural risks, and better results long-term."

TAVR for High-Risk Patients.

The first arm of the PARTNER study randomized 700 high-risk patients to surgical valve replacement or TAVR, and analyzed deaths, hospitalizations, and strokes. It also assessed how well the new valve performed, how far patients could walk, and how they viewed their quality of life. In all measures, the results of TAVR and surgery were similar. TAVR for Inoperable Patients.

The second arm of the PARTNER study randomized more than 350 inoperable patients to standard treatment with medical therapy or balloon valvuloplasty, or to TAVR. Five years later, only 6 percent of the standard treatment group was still alive, compared with 28 percent of those who had undergone TAVR.

Valve-in-Valve TAVR.

In clinical trials, TAVR is being used in place of a second valve replacement. In this procedure, called valve-in-valve TAVR, a new valve is inserted inside a failed bioprosthetic valve. At one year, about 83 percent of these patients are still alive and enjoying significant improvement in heart function and quality of life.

Excitement Ahead.

Although TAVR provides a valve-replacement option for patients who have no other choice, researchers are already improving the odds of success by tweaking the design of the valve and its delivery system.

The PARTNER trials were conducted with a first-generation, balloon-expandable valve. Since that trial started, new self-expanding valves are producing even better results. This has opened the door to trying TAVR in patients at moderate risk for surgery and with other, less-dire forms of valve disease.

All patients who undergo TAVR are tracked in U.S. or international registries, which allow researchers to see where the problems are occurring and make necessary adjustments to improve outcomes. New valve designs and pre-procedure testing protocols are ensuring that valves fit tightly. Smaller catheters and better selection of candidates for TAVR are helping prevent injury to the blood vessels. Filters are being tested to protect the brain and minimize stroke risk. And because so many patients undergoing TAVR have kidney disease, cardiologists now take steps to protect existing kidney function.

As with any new procedure, experience is limited to a small number of medical centers. To ensure the best results for any individual with aortic stenosis, the decision to recommend TAVR or surgical valve replacement should be made by a team of physicians and surgeons with experience in both methods.

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