Features December 2014 Issue

TAVR an Expanding Option for Patients with Aortic Valve Disease

Transcatheter aortic valve replacement (TAVR) is widening its reach as new valves reach the market and a broader pool of patients

In the three years since the U.S. Food and Drug Administration (FDA) approved the first artificial valve for use in transcatheter aortic valve replacement (TAVR), two new valves have also been approved, and more types of patients are being considered for this increasingly common treatment.

Photo: Thinkstock

The first valve approved was the Edwards SAPIEN Transcatheter Heart Valve, and it was only for patients with severe aortic valve stenosis, who were unable to undergo open-heart surgery. Today, a second Edwards valve, the SAPIEN XT, is available. It’s smaller, which means it can be delivered to the heart through narrower arteries with less chance of the catheter causing injury to the blood vessels. And earlier this year, the FDA approved Medtronic’s CoreValve.

Procedure illustration reprinted with permission, Cleveland Clinic Center for Medical Art & Photography

In a transcatherer aortic valve replacement, a catheter is guided to the heart and a small balloon is inflated to open the valve in what is called valvuloplasty (A). A catheter carrying a balloon and artificial valve (B) is then deployed (C) and withdrawn (D) once the new valve is in place.

“Things have changed a lot,” says Cleveland Clinic interventional cardiologist Samir Kapadia, MD. “It’s a very exciting time in this field.”

Among the other big changes is the broadening pool of patients who may be considered for this life-altering treatment. Instead of only inoperable patients, now patients considered “high risk” for open surgery may be candidates for TAVR. And Dr. Kapadia adds that two large clinical trials of patients considered at “intermediate risk” for TAVR have been completed. Results are expected to be published in early 2015.

Advantages of TAVR
Dr. Kapadia also presented research recently at the Transcatheter Cardio­vascular Therapueutics scientific symposium that after five years patients who underwent TAVR had lower rates of mortality and re-hospitalizations, as well as improvements in everyday functioning at home when compared to inoperable aortic valve disease patients who received standard care that included medications but no interventions. Dr. Kapadia noted that, on average, TAVR patients in the study lived about two-and-a-half years after the procedure. Patients on standard therapy lived less than one year. “And these two-and-a-half years are a functionally good two and a half years, not two-and-a-half years as an invalid,” he said at the symposium.

Dr. Kapadia adds that survival rates are likely to improve in the years ahead with the advances in valve technology and physician experience with the procedure.

How TAVR works
TAVR is a minimally invasive procedure that repairs a damaged or diseased aortic valve without removing the natural valve. A catheter fitted with a collapsible replacement valve is guided to the site of the diseased valve. Usually the patient’s condition is aortic valve stenosis, which means the valve between the heart and the aorta is stiff and won’t open fully to allow proper blood flow. Once the new valve is in position, it is expanded, pushing the old valve leaflets out of the way. The prosthetic valve’s leaflets then take over the control of blood flow.

TAVR can be peformed by inserting the catheter through the femoral artery, a large blood vessel in the groin. This is called the transfemoral approach. The procedure can also be done through a small incision in the chest, from which the catheter is guided through a large artery in the chest or through the tip of the left ventricle. This is called the transapical approach.

Aortic valve replacement can also be done through open surgery, but TAVR has been a life-saving development for individuals considered high-risk for surgery or inoperable.
One of the benefits of these second-generation replacement valves is that they can be repositioned as needed to make sure there is no leakage. Dr. Kapadia explains that newer valves have a collar that fits around the valve to help prevent leakage and ensure healthy blood flow. The first generation of valves used in TAVR were not as easily manuevered.

Dr. Kapadia believes more encouraging developments are ahead. Currently, people at low surgical risk are still advised to have aortic valve replacement done through open surgery. But if studies continue to show the merits of TAVR, it may become much more widely performed.

 

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