It is a tale of one transcatheter heart valve (the Sapien) with two approaches: enter through an incision in the groin and thread up through the femoral artery (transfemoral); or enter between the ribs and through the bottom part of the heart (transapical).

Edwards Lifesciences (Irvine, California) reported Tuesday that FDA has approved the addition of its Ascendra transapical delivery system to its Placement of Aortic Transcatheter valves (PARTNER) trial. The agency also gave Edwards permission to increase its trial sample size from 600 to 1,040 patients.

The PARTNER trial, initiated last year, is evaluating the company’s Sapien valve in patients who are considered high risk or inoperable for conventional open-heart surgery.

Until now, clinicians in PARTNER delivered the Sapien valve using Edwards’ RetroFlex transfemoral delivery system by making a small incision in the patient’s groin and threading the catheter up through the femoral artery. Now, trial clinicians have a second approach to choose from. The Ascendra transapical delivery system delivers the valve by surgically inserting it between the patient’s ribs and entering through the bottom part of the heart.

The transfemoral approach is performed in a cath lab by an interventional cardiologist, whereas the transapical procedure is performed in the operating room by a cardiac surgeon.

Adding the Ascendra transapical delivery system to the trial is important because not all patients who could benefit from the Sapien valve can be accessed through the femoral artery, Larry Wood, VP and general manager of transcatheter replacement at Edwards, told Medical Device Daily.

With these trial revisions, patients with symptomatic, calcific aortic stenosis – a narrowing of the aortic valve that reduces the outward flow of oxygenated blood – will be evaluated for inclusion in one of two separate treatment arms, surgical or medical management, Edwards said.

“This approval is a really big deal for all the surgeons in the trial because it gives them a chance to do this procedure and help their patients,” Wood said.

Every site in the PARTNER trial has a cardiac surgeon co-principal investigator as well as an interventional cardiologist co-principal investigator, Wood said, in an effort to conduct the trial as a team approach.

Thus, the “partnership” between the interventional cardiologist and the surgeon is one rationale for the trial’s title, he said.

“The addition of the transapical approach to the PARTNER trial is an important milestone for cardiac surgeons and their patients. The transapical approach greatly expands the options for patients who need aortic valve replacement, but face excessive risk with alternative approaches,” said Craig Smith, MD, chief of cardiothoracic surgery at New York-Presbyterian Hospital/Columbia University Medical Center and the co-principal investigator for the U.S. PARTNER trial.

From the company’s perspective, Wood said the addition of the transapical approach should help speed up trial enrollment because a “significant percentage” of patients were getting screened out because of the femoral access issue.

The surgical arm of the trial evaluates the Sapien valve and the two transcatheter delivery systems – Ascendra for transapical access, and RetroFlex for transfemoral access – as compared to surgical, open-heart valve replacement. The medical management arm of the trial evaluates the Sapien valve with the RetroFlex transfemoral delivery system as compared to appropriate medical therapy.

While Edwards has developed one valve (the Sapien) with two approaches (RetroFlex transfemoral or Ascendra transapical), Wood told MDD in March “at the end of the day how you deliver the valve is less important than the valve itself,” (Medical Device Daily, March 22, 2007).

The Sapien transcatheter heart valve integrates balloon-expandable stent technology with a replacement tissue heart valve. The Sapien valve is compressed onto the balloon to about the diameter of a pencil and is threaded through the patient’s circulatory system from either the leg (using the transfemoral approach), or it is inserted between the ribs (using the transapical approach), and expanded directly over the aortic valve.

“The addition of the Ascendra transapical delivery system to the PARTNER trial will enable Edwards to address a larger population of patients who may have few or no options for treatment of their heart valve disease,” said Michael Mussallem, Edwards’ CEO and chairman. “Incorporating Ascendra along with increasing the number of patients in the trial also will better ensure that the trial endpoints are successfully met.”

The merits of transfemoral vs. transapical delivery is an emerging area of controversy in transcatheter valve development, as reported by MDD’s sister publication, Cardiovascular Device Update, last spring. Kenton Zehr, MD, of the Heart, Lung and Esophageal Surgery Institute at University of Pittsburgh Medical Center, discussed the topic last year at the annual conference of the American College of Cardiology (ACC; Washington), during a session on percutaneous heart valve therapy (CDU, April 1, 2007).

The transapical approach, which typically is performed via a mini-thoracotomy, can be accomplished either by using beating heart or stopped-heart techniques, i.e., either with or without extracorporeal circulation. That’s why procedures performed using a transapical approach fall into the realm of the cardiac surgeon, whereas those using a transfemoral approach are more suited to the interventional cardiologist.

Zehr argued that the transapical approach avoids risk of damage to vascular structures that must be crossed using the transfemoral approach, and also allows use of larger-diameter and stiffer delivery catheters, which, at least with existing technologies, facilitates precise placement of the valve.

The Sapien valve with the Ascendra transapical and RetroFlex transfemoral delivery systems is available in Europe. The device received CE-mark approval with the RetroFlex delivery system last September, and with the Ascendra system in December.