Caution Urged in Widespread Adoption of TAVR

SAN FRANCISCO, CALIF.—In light of the recent FDA approval of  the first percutaneous artificial valve for patients with severe aortic stenosis ineligible for surgery, the topic of whether to quickly adopt transcatheter aortic valve replacement as a frontline treatment was a topic of much debate at TCT 2011. The panel, which included a surgeon, an interventionalist and a cardiologist, conceded that due to the threat of uncontrolled adverse effects, the risks inherent in rapid adoption, and the need to build consensus among a multitude of constituencies, cautious adoption is recommended.

Craig R. Smith, MD, a surgeon from Columbia University, New York, who also is co-principal investigator of the PARTNER trial, said that the risk of stroke inherent in TAVR is a factor that needs to be considered when selecting treatment. In The PARTNER trial, for example, at both 30-day and 1-year follow-up, neurologic events such as stroke/TIA, major stroke and death from major stroke were nearly double in TAVR patients (n=348) vs. AVR patients (n=351) (see Figure), Smith said.

Martyn R. Thomas, MD, an interventionalist from St. Thomas Hospital in London, countered that stroke risk in these patients might be reduced by “optimal and standardized pharmacology.”

Thomas also indicated that paravalvular regurgitation is another concern, citing data from a German transcatheter aortic valve interventions registry showing that aortic regurgitation values at or greater than 2/4 are the highest predictors of in-hospital mortality, low cardiac output and respiratory failure.

Too rapid vs. not rapid enough

Regarding rate of adoption of TAVR, Smith suggested that the debate could be framed by the cost benefit of either option. “From the perspective of the PARTNER 1-A results, if rapid adoption is considered to be putting this into patients with STS greater than 4, I think from most perspectives … this is not going to be too fast, although the payers might disagree,” Smith said.

Because the percentage of patients with a score greater than 4 is less than 25% of the surgical population, however, Smith also said that rapid adoption of TAVR within reason makes sense, “because we’re not giving the benefit of this treatment to the other 75% [of patients].”

Thomas said that ultimately the choice to proceed with TAVR should not be an “either, or” question, but should be based upon the needs of the individual patient. “There should be cautious adoption in high-risk surgical patients,” he said.

Patrick T. O’Gara, MD, of Brigham and Women’s Hospital, Boston, agreed with this approach, saying that matching the appropriate device with the appropriate patient is critical. “It bothers me a little bit that in the United States, we have a dichotomy of choices with respect to centers that provide only the Medtronic valve versus centers that only provide the Edwards Sapien valve,” he said. “We’re going to be years behind before interventionalists and heart teams can decide the appropriate device per patient, per center.”

Team approach advocated

Thomas emphasized that while the rate of adoption should be dictated by heart teams, “surgeons should remain the ‘gatekeepers’ of the procedure.” Smith also said that a multidisciplinary approach should be rooted in a “culture change” and that the move to TAVR in aortic stenosis would be a long-term process. “It’s an important but somewhat fragile concept,” he said. “Interventionalists and surgeons need to learn to think alike, and these kinds of changes do take time.” Differences between the two specialties, said Smith, include that surgeons are more accustomed to dealing with catastrophic outcomes such as death and stroke.

Additionally, Smith said that surgeons were more likely to have better rapport and more intense relationships with their patients and families, while with some exceptions, interventionalists do not, in large part because they have much lower catastrophe rates. “In [the interventional] setting it’s a lot easier to tell yourself that these [catastrophic events] just don’t happen,” he said. “Interventionalists need to understand that entering the valve space requires ‘broader shoulders’ and that there is risk.”

O’Gara tracking outcomes in a transcatheter valve therapy registry will ensure that clinicians of all specialties are “held to a very high standard.”  He also said that value must be measured to track incremental costs, for the quality that is provided to the patient.