TAVR proliferation linked to better outcomes, more options for patients

The introduction of transcatheter aortic valve replacement for the treatment of aortic stenosis has increased the number of patients eligible for aortic valve replacement and also has led to a decrease in patient mortality, according to findings presented at the 50th Annual Meeting of the Society of Thoracic Surgeons.

The results suggest that patients fare better when multiple treatment options are available, J. Matthew Brennan, MD, MPH, of Duke University Medical Center, and colleagues reported.

“Early in the TAVR experience, there was concern that the availability of transcatheter procedures would lead to an abrupt reduction in the volume of surgical valve replacements,” Brennan stated in a press release. “Our findings confirm what other surgeons have observed — implementation of a TAVR program likely will broaden the surgical referral base and increase the volume of patients considered for treatment.”

Increased volume

The researchers conducted a review of data from the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database (2008-2012) and the STS/American College of Cardiology Transcatheter Valve Therapy Registry (2012) to evaluate the association between TAVR availability and subsequent volumes and outcomes for TAVR and surgical aortic valve replacement (AVR).

Results were reported for all cases as well as stratified by low- (STS Predicted Risk of Mortality [PROM] <4%), intermediate- (STS PROM 4% to 8%) and high-risk (STS PROM >8%) cases.

Annual volume of aortic valve interventions increased from 34,699 in 2008 to 43,282 in 2012, which researchers attributed to expanded use of surgical AVR in low- and intermediate-risk patients and expanded use of TAVR in high-risk patients.

This is important because results from a 2009 study demonstrated that “52% of patients with severe aortic valve disease never undergo an operation,” Brennan said during a press conference. “Their mortality is expected to be around 50% at 2 to 3 years. But valve replacement can bring them back to a normal survival curve. The most common reason why the therapy is not delivered is perceived risk.”

When TAVR became commercially available in the United States in 2012 and its use was no longer limited to patients enrolled in clinical trials, the volume of high-risk surgical aortic valve replacement cases declined, but the combined volume of surgical AVR and TAVR procedures in high-risk cases nearly doubled, from 4,249 cases in 2011 to 8,082 cases in 2012.

“More patients are coming in for diagnosis and treatment,” Brennan said. “Some of those are appropriate for surgery, some are appropriate for transcatheter therapies.” TAVR centers saw a higher rate of increase in surgical AVR volume than did centers not offering TAVR, likely because doctors are writing referrals with TAVR in mind, he noted.

The commercial introduction of TAVR also led to improved outcomes, Brennan said. Observed in-hospital mortality for TAVR and surgical AVR combined declined from 8.9% in 2011 to 7% in 2012. This outcome improved over time for low-, intermediate- and high-risk patients, he said.

There was no difference between the rate of improvement in in-hospital mortality for low-risk patients at TAVR centers and non-TAVR centers. However, for high-risk patients, the rate of improvement was better at TAVR centers than non-TAVR centers.

“A second mode of treatment is typically good for patients,” Brennan said. “You can fit patients to the appropriate treatment, rather than fitting a square peg into a round hole.”

Other findings

However, in-hospital mortality for patients who underwent TAVR increased after commercialization, Brennan said.

“What we saw in clinical trial results was that TAVR outcomes were tremendously better than expected,” he said. “But once we reached commercialization, the technology was dispersed from about 60 centers to about 250 centers, and we saw a difference in patients who are being selected for the procedure. Even after we risk-adjusted for those differences and casemix, we saw almost a doubling in the risk for in-hospital mortality for those patients.”

In-hospital mortality rates for TAVR remained lower than for surgical AVR, he noted.

Follow-up studies will examine why there was an uptick in TAVR-related in-hospital mortality. Brennan noted that hypotheses include differences in case selection not accounted for by current risk adjustments; lower volumes the centers that did not perform TAVR until commercialization; and learning curves occurring prior to 2008 in centers that had TAVR clinical trials but not occurring until 2012 in centers that did not perform TAVR until commercialization.

Disruptive technology

The increase in complications with a newer technology is not surprising, Joseph E. Bavaria, MD, of the Hospital of the University of Pennsylvania, said at the press conference.

“Any time you introduce new surgical technology to a larger population of physicians who are implementing it, and to a larger group of patients, there is virtually always an increase in complications as a result of that. We’ve seen that in every new technology, whether it be in cardiac or thoracic surgery.

“The beauty of this trial, at a time when CoreValve (Medtronic) is about to be introduced, is that it shows [TAVR’s] value and that it is disruptive technology. It’s so important that we have this data, that we’ve rolled [TAVR] out carefully, and that we’ve done it in high-risk patients with good results,” Bavaria said. – by Erik Swain

For more information:

Brennan JM. General Session I: Richard E. Clark Paper for Adult Cardiac Surgery. Presented at: STS 50th Annual Meeting; Jan. 25-29, 2014; Orlando, Fla.

Disclosure: Brennan reports no relevant financial disclosures. Bavaria reports financial ties with Edwards Lifesciences, Medtronic and St. Jude Medical.