Is it possible to score two home runs with a single hit? The Society of Thoracic Surgeons achieved that this week during their annual meeting in Orlando, Fla.
The double homer involved study results presented by J. Matthew Brennan, MD, MPH, at cardiologist at Duke University Medical Center in Durham, N.C. Brennan and colleagues combined data from the STS Adult Cardiac Surgery Database and the STS/American College of Cardiology Transcatheter Therapy Registry to track volume and outcomes of patients who underwent surgical or transcatheter aortic valve replacement (TAVR). Their questions: Had the commercial introduction of a TAVR device in the U.S. affected hospitals’ case volume and patient outcomes?
Even before Edwards Lifesciences’ Sapien valve was approved for inoperable patients with severe aortic stenosis in 2011 and for high-risk patents the next year, researchers in the PARTNER clinical trial were observing a “halo effect.” Patients who were reluctant to have an operation for their condition, or their primary care physicians who hesitate to refer them, saw the less invasive TAVR as an option. Those who were not candidates for TAVR then were appropriately approached for surgical AVR.
The result, anecdotally, was an upsurge in surgical AVR volumes at TAVR centers. Brennan and his team put evidence behind the observation. They found that volumes increased for both TAVR and surgical AVR centers, with TAVR centers experiencing the greatest gains.
What this means is that many patients with aortic stenosis who sat at the sidelines now seek treatment, and this is a good thing. An increase in surgical AVR volume also is likely to benefit hospitals’ bottom line, and this is also positive, especially if that offsets potential losses from TAVR. Results from Brennan et al may help TAVR centers make a case for resources.
The data on patient outcomes focused on inhospital mortality. Overall, mortality had dropped for low-, intermediate- and high-risk patients. By the second quarter of 2013, the observed-to-expected ratio of inhospital mortality for surgical AVR high-risk patients dropped close to that for high-risk TAVR patients. From 2008 to mid-2013, the mortality trajectory declined for high-risk TAVR patients, but it shot up after the FDA’s approval.
There are many possible reasons for this trend. Learning curves, low volume and other factors involving the addition of TAVR centers may come into play, despite the careful and limited dispersion of the technology in the U.S. Patient selection also is pivotal, although the analysis accounted for that.
“Once we risk adjust for most of the characteristics that we would expect would make a difference, though, we are still seeing mortality rates increasing, suggesting it may be more than just patient selection,” Brennan said in an interview.
The mortality finding also rates as a home run. TAVR is under a microscope, and identifying early circumstances or practices that could derail its success will help keep the technology viable. Brennan and his colleagues are continuing to evaluate the data. This won’t be the last we hear from them, or from others scouring the registry data.
Candace Stuart
Cardiovascular Business, editor