Penn’s School of Medicine is one of 22 institutions nationwide participating in a clinical trial for a procedure that may offer high-risk heart patients a safer alternative to open-heart surgery.
The PARTNER Trial, which stands for Placement of Aortic Transcatheter Valves, tests an alternative procedure for patients with severe aortic stenosis, called transcatheter aeortic valve implantation, or TAVI.
In patients with the disease, the aortic valve is “blocked with calcium, and the heart needs to work harder to eject blood through the valve to the rest of the body,” according to Howard Herrmann, director of cardiac catheterization at the Hospital of the University of Pennsylvania and one of the heads of the Penn trial.
Herrmann explained that traditional treatment for the disease is open-heart surgery, during which patients are put on a heart-lung bypass machine while surgeons take out the old valve and put a new one in its place. Open-heart surgery, however, poses a higher risk for patients with severe aortic stenosis.
The TAVI procedure, which is less invasive than its traditional counterpart, uses a device created by study sponsor Edwards Lifesciences. In a catheter-based process, doctors implant a new valve inside the old one through an artery in the leg or groin.
The trial is divided into two portions. The first began in November 2007 and ended this spring, with its results recently published in this week’s print issue of the New England Journal of Medicine.
Herrmann said the first part of the trial studied the TAVI procedure in patients who are “too old or too sick for open-heart surgery.” The second portion, which is currently being conducted and anticipated to be completed by the end of the year, compares the new therapy to traditional open-heart surgery “in high-risk, but not prohibitive-risk patients,” he said.
The device, known as the SAPIEN valve, has already been approved in Europe. According to Herrmann, the standard for approval in Europe measures safety, while the U.S. Food and Drug Administration measures both safety and efficacy. The device must, therefore, prove to be “as good as or better than another therapy,” he said.
This “cumbersome” approval process, noted Joseph Bavaria, vice chief of Penn Med’s Division of Cardiovascular Surgery and co-leader of the Penn trial, contributes to why the United States has not yet adapted the procedure.
The PARTNER trial is unique in that it calls for a “multidisciplinary team,” according to Herrmann. Generally, “if you need a stent,” a tube inserted into a blood vessel to improve blood flow, “you go to an interventional cardiologist. If you need heart surgery you go to a surgeon,” he said.
“This is a novel procedure and novel approach where both of our skill sets are utilized,” he added. Herrmann and Bavaria have operated together on over 100 patients since the start of the trial in November 2007, and over 100 more are still on the waitlist.
Bavaria said the TAVI procedure will likely open up new treatment options for those high-risk or inoperable patients, estimating that 35,000 to 50,000 people, who would not otherwise receive the valve implantation, will benefit from the procedure once it is approved.
“It’s life saving,” he said.
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