Aortic Valve Replacement | Replacing a heart valve – one of the trickiest, most difficult and most dangerous things a human can do to strengthen the structure of a heart – is about to become a minimally invasive procedure. The procedure, transcatheter aortic valve replacement surgery, or TAVR (pronounced TAY-ver), is coming to UCH as soon as March, and the hospital’s Valve Clinic will be the first – and for a time the only – hospital in the state to offer it.
TAVR stretches the imagination nearly as much as it helps patients. Imagine replacing a car-engine cylinder via the tailpipe, and you’re in the conceptual ballpark. Instead of cracking open the chest, clinicians make a small incision in the groin, then replace the heart’s aortic valve – oxygen-rich blood’s gateway to the body – via a catheter thin enough to be threaded through the vascular system to its intended target.
And imagine doing it for the kind of extraordinarily sick, typically elderly patient who suffers from a structural problem like that.
Lorna Prutzman, RN, MSN, executive director of the Cardiac and Vascular Services, calls these patients “the frailest of the frail.” Their median age is 83.
The U.S. Food and Drug Administration approved the implantable stent valve and delivery system used for the procedure in November 2011 for patients who have aortic stenosis and who are not eligible for surgery. Aortic stenosis, in which a creaky, narrowed aortic valve starves the body of blood flow, is itself often a function of age. It afflicts about eight percent of those over 85 years old, according to John Carroll, MD, director of Cardiac Interventions at UCH.
Carroll is now leading the hospital’s multidisciplinary roll-out of the hospital’s TAVR program.
Often, Carroll explained, these patients’ frailty or other high-risk factors preclude traditional aortic-valve replacement surgery.
For many, that’s meant living with low energy, dizziness, shortness of breath, chest pain and other serious symptoms that lead to frequent hospitalizations and a terrible quality of life. Recent data showed aortic valve disease had higher mortality rates than most cancers, Carroll said, with more than half of inoperable patients dying within a year.
The new alternative to open-heart surgery is a bioprosthetic valve dubbed the SAPIEN,® and a system that snakes it into the heart, both made by Edwards Lifesciences of Irvine, Calif. In the procedure, an interventional cardiologist threads the new valve – crimped down on a delivery balloon catheter to roughly the diameter of a #2 pencil – through the femoral artery and into the beating heart.
Using 3-D ultrasound and fluoroscopy, doctors position the SAPIEN® valve inside the patient’s damaged aortic valve. A balloon expands the new valve to just under an inch in diameter, squashing and then taking over for the damaged valve (to see an animation of how the procedure plays out, click here).
TAVR is a demanding procedure, involving specialists in interventional cardiology, cardiac surgery, cardiac imaging, and cardiac anesthesia, among other areas Carroll estimates that fewer than five percent of U.S. cardiologists have the experience and skills even to attempt TAVR. But he and colleague John Messenger, MD, who will be performing TAVR at UCH, have the benefit of having done transcatheter insertions of MitraClips to close leaky mitral heart valves, among other interventions, he adds.
“There are a variety of skill sets that one needs to have conquered before you start doing this,” Carroll said. Adding to the challenge is that, given how sick the aortic stenosis patients often are, “there’s not much margin for error,” he said.
The UCH TAVR team is currently in the midst of a 10-week training program on the finer points of the procedure, Messenger added.
TAVR works, according to the clinical trial that led to its FDA approval.
Two years after the procedure, the all-cause mortality rate was 36 percent lower among those who underwent TAVR than among those who didn’t. In addition, TAVR hospital stays were six days shorter, admissions costs were $2,500 lower, and patients had higher quality-of-life scores the month after the procedure.
TAVR is not without risk, though. More than 43 percent of the patients who got the procedure during the trial died within two years, an indication of the frailty of the patients. Including minor strokes, those who underwent TAVR had a stroke rate of 13.8 percent at two years, compared to 5.5 percent for those who didn’t have the procedure.
In addition to stroke risk, Carroll said, there’s the risk of ruptured blood vessels (the crimped valve is still a millimeter or two wider than the average femoral artery). If the valve is implanted more than a couple of millimeters out of place, he added, it can break loose and ride the circulatory system to destinations unknown.
Stroke, though, is the top concern, and to help manage the risk, William Jones, MD, who co-chairs the UCH Stroke Program, will be part of the TAVR team.
Going forward, one can probably expect increasing numbers of aortic valve replacements to be done via leg arteries. A follow-up clinical trial is considering the relative benefit of TAVR versus traditional aortic-valve surgery among patients who can tolerate surgery. The next-generation Sapien valve will be narrower when crimped, making it easier on leg arteries.
Medtronic is in trials with a competing TAVR system, called CoreValve.
Ultimately, TAVR will be good for patients as well as for UCH, Prutzman said.
“These are high-end procedures that are technically difficult and very specialized, and we have a great team of people who work well together at that level to pull this off,” Prutzman said. “This is what an academic medical center is meant to do.”
Know a TAVR candidate?
UCH is looking for patients eligible for transcatheter aortic valve replacement (TAVR). Know of someone who has aortic stenosis but can’t undergo traditional aortic valve surgery? Contact the Cardiac & Vascular Center at (720) 848-5300.