A Lower Risk Threshold for TAVR?

Published in Cardiovascular Report - Winter 2016

Aortic stenosis affects about 12 percent of people over 75, about a fourth of whom have disease so severe it mandates surgical repair. Many, however, have intraoperative risk that renders them poor candidates for open-heart surgery, the gold standard approach.

For nearly a decade, the less invasive transcatheter aortic valve replacement (TAVR) has gained ground as the safer alternative for people at high operative risk, generally defined as 10 percent or higher. Many patients older than 80 will fall in that category, as will some  younger patients with extensive comorbidities. 

At 80 and otherwise healthy, Joyce Wetzler belonged in neither group. She was diagnosed at Johns Hopkins two years ago after experiencing increasing shortness of breath and worsening fatigue. After a series of echocardiograms, Wetzler was referred for evaluation to cardiac surgeon John Conte and interventional cardiologists Jon Resar and Rani Hasan.

Currently, the sole option for most people like Wetzler is open-heart surgery. At Johns Hopkins, she had the choice of enrolling in a clinical trial evaluating the efficacy and safety of TAVR for intermediate-risk patients. “I thought, I could die having open-heart surgery, and I could die having the minimally invasive one,” she says. “I figured if I had the second, I might help others and do my part for science.” 

With Wetzler under light sedation, Hasan, part of a five-member clinical crew, performed the procedure in August 2015. After examining intraoperative images, Resar later told Wetzler that her native valve leaflets had been opening only a few millimeters. Without surgery, she would have likely died within the year.

Wetzler was discharged home two days after her procedure. A month later, she was running laps with her Old English sheepdog at a dog show. Save for a few hypertensive spikes, she’s been feeling great. “I remember walking toward Madison Square Garden last winter and barely catching my breath,” Wetzler says. “That’s all gone now.”

A Study to Bring Clarity

Even though transcatheter aortic valve replacement (TAVR) carries a decidedly lower operative risk for older and/or medically frail patients than open-heart surgery, for intermediate-risk patients, the risks and benefits are less clear.

“Most patients with an intermediate-risk profile can undergo open-heart surgery relatively safely, but their risk is still a tad higher than we’d like it to be,” says Conte, who with Resar is heading the Johns Hopkins arm of an ongoing multicenter trial called SURTAVI. “Our current trial aims to gauge the pros and cons of either approach in this particular subset of patients.” The primary outcome measures of the study, which will include five-year follow-up, are all-cause mortality or disabling stroke at two years.

In high-risk patients, TAVR carries a notably lower mortality risk (14 percent versus 18 percent) at one year, and a comparable stroke risk. But TAVR patients are more likely to require a pacemaker due to conduction system damage during the procedure. Some 15 to 20 percent of TAVR patients end up needing a pacemaker around the time of the procedure, compared with 5 percent in open-heart surgery, but many of them have underlying conduction disease related to aging that requires pacing anyway, Conte says.

Eight out of 10 TAVR patients need only light sedation and are often able to go to a regular hospital unit rather than an ICU after the procedure. In addition, says Resar, Johns Hopkins experts typically opt for a percutaneous catheter insertion rather than a surgical cut-down to further minimize recovery time. Subclavian artery entry is always an option, but about 90 percent of Johns Hopkins cases are done using iliofemoral insertion because of its lower complication rate.

“Patients are up and moving around the same day,” says interventional cardiologist Rani Hasan. “Most go home in two to five days.”

Regardless of the trial outcomes, a multidisciplinary, case-by-case assessment will remain the centerpiece to optimizing outcomes in individual Johns Hopkins patients, Resar says.

At Hopkins, the preoperative work-up involves two to three pre-procedure visits, an echocardiogram, a CT scan, a pulmonary function test and a carotid ultrasound. Each case is then discussed by a team of clinicians including a cardiologist, a surgeon and an interventional cardiologist.