TAVI Is Broadening the Treatable AS Population, Not Cutting Into SAVR

Not only is TAVI bringing aortic valve replacement (AVR) to a wider range of US patients with severe symptomatic aortic stenosis, but it has also yielded better outcomes over time, according to an analysis of the National Inpatient Sample.

The number of patients treated with TAVI rose from just 6,470 in 2012 to 57,155 in 2018, with the procedure overtaking surgery in terms of the share of all AVRs during that span. TAVI accounted for 11.1% of AVRs in 2012 and 58.0% at the end of the study period, lead author Katherine Clark, MD, MBA (Yale University School of Medicine, New Haven, CT), and colleagues report in a research letter recently published online in the American Heart Journal.

But SAVR volumes did not fall very much during TAVI’s growth, with 44,117 surgical replacements performed in 2008 and 41,455 in 2018.

That is “quite encouraging,” Clark told TCTMD. “It suggests that we’re reaching an increased number of patients with severe aortic stenosis and making a meaningful impact on a broader patient population.”

Moreover, there were reductions in in-hospital mortality, length of stay, and procedural costs associated with TAVI over time. “It hits the triple aim of healthcare—the outcomes have improved, the cost and resource utilization have decreased, and access to this technology has grown to a broader population,” Clark said.

Still, commented Benjamin Wessler, MD (Tufts Medical Center, Boston, MA), another key finding is that there are lingering racial/ethnic disparities in access to TAVI and SAVR, despite some gains during the study period.

“Treatment of white patients dominates the national landscape, and I think while [Clark et al] identify a modest increase in the number of Hispanic patients that are treated, really I think the observation is that there’s profound undertreatment of underrepresented minorities in this space,” he said, calling for more research into the underlying reasons.

Clark acknowledged that “we still have a lot of work to do, but the needle is definitely moving in the right direction.”

National Trends

Since the first TAVI device was approved in the United States in 2011—the Sapien valve (Edwards Lifesciences)—the procedure has taken off, with indications widening from inoperable patients to include patients at moderate then low surgical risk.

Turning to the National Inpatient Sample, Clark et al set out to examine how the AVR landscape has changed since then. The analysis included 208,500 admissions for TAVI between 2011 and 2018 and 540,775 admissions for SAVR (with concomitant procedures in 12.5%) between 2008 and 2018.

The total volume of AVR procedures increased from 58,120 in 2012 to 98,610 in 2018 (P < 0.001), the net effect of a surge in TAVI and a slight decline in SAVR.

On average, patients undergoing TAVI were much older than those undergoing surgery (mean age 80.1 vs 68.9), although age skewed lower for the transcatheter approach over time. Most patients, regardless of AVR type, were men (53.7% for TAVI and 65.7% for SAVR) and white (87.0% for TAVI and 83.8% for SAVR). The proportion of patients undergoing TAVI who were Hispanic increase from 2.4% in 2012 to 5.6% in 2018 (P < 0.001).

Socioeconomic status and geographic region did not have a strong relationship with AVR use. Medicare was the primary payor for both TAVI (90.0%) and SAVR (65.4%), although that number declined slightly over time for the transcatheter intervention.

Both procedures were performed mostly at large teaching hospitals in urban areas for the overall study period, but they were increasingly done at small- and medium-sized hospitals over the years.

From 2012 to 2018, the proportion of patients discharged home increased for TAVI (64.2% to 86.1%), with a smaller change for SAVR (68.7% vs 76.0%). Median length of stay fell from 6 to 2 days for TAVI (P < 0.001), with no change for SAVR (median 7 days throughout).

In-hospital mortality was lower overall with TAVI than with SAVR (1.9% vs 2.7%) and declined to a greater extent during the study with the transcatheter approach (from 4.5% to 1.4%) than with surgery (from 2.7% to 2.2%). The authors caution, however, that “mortality was not adjusted between groups, so differences in indications between procedures, which are more extensive for SAVR than those for TAVR, may have affected the observed mortality and length of stay [differences].”

Total hospital costs also fell over time for TAVI, from a median of $61,508 in 2012 to $47,642 in 2018, while remaining relatively stable for SAVR; costs of transcatheter and surgical treatment were roughly equal at the end of the study period.

What’s Behind the Improvements in TAVI?

Clark et al say the positive trends in TAVI results are likely related to multiple factors, “including optimized valve design with improved hemodynamics, improved operator skills and procedural training, as well as fewer periprocedural complications.” The lower costs, they continue, “can potentially be attributed to a shorter length of stay and fewer periprocedural complications. The inclusion of lower-risk patients is also likely contributing to the improved in-hospital mortality and lower total cost; however, further understanding is needed regarding TAVR valve durability as indications expand.”

Wessler also attributed gains in TAVI to improvements in performing the intervention and to changes in the types of patients getting treated. “We’re better at providing this procedure to patients with respect to procedural success and systems of care to move patients through the hospital safely,” he explained. “Additionally, the patients who are being treated now generally are less sick than they were in 2011, and that’s as the surgical risk, or the procedural-risk profile, has marched down as [TAVI] has been available to a wider set of patients given clinical trial data.”

The fact that SAVR volumes didn’t go down much despite a rapid rise in use of TAVI is not particularly surprising, Wessler commented, because other studies have shown a stabilization of SAVR rates. “There are a number of patients . . . who are optimized with an open technique, and that cohort will persist through the years,” he said, pointing to younger patients, those with bicuspid valves, and those who also require CABG. “And I also think as there’s increased recognition of the need to identify and refer and treat symptomatic aortic stenosis, the rates of surgical AVR will be maintained.”

Ultimately, Clark said, “we hope that the use and adoption of TAVR continues to expand as we’ve shown that even over a relatively a short time period, the use of TAVR has made a dramatic impact on a common cardiovascular disease, allowing for a substantially increased number of patients who can obtain an aortic valve replacement.”