Ten-Year Trends in the UK Show TAVR Rates Rising but SAVR Holding Steady

London, ENGLAND—Ten years after transcatheter aortic valve replacement was introduced in the United Kingdom, the number of patients undergoing the procedure has, not surprisingly, increased exponentially. But in contrast to other parts of the world, the volume of patients undergoing surgery has not significantly dipped, new research shows.

Importantly, rates of early mortality have declined for both procedures, said Tom Cahill, MBBS (Oxford University Hospitals, England), who presented the data here at PCR London Valves 2018.

“There has been dramatic growth in the use of TAVI in the UK between 2007 and 2016, accompanied by significant reduction in in-hospital mortality,” he said. “Unlike in some other cohorts, notably in Germany, the number of SAVR procedures has not changed significantly to date.”

Cautious, Conservative Update

Cahill and colleagues used prospectively recorded patient numbers, characteristics, and hospital outcomes from the National Institute for Cardiovascular Outcomes Research (NICOR) UK TAVI and Adult Cardiac Surgery databases, looking at temporal trends in the use of isolated surgical aortic valve replacement (SAVR) and TAVR procedures between 2007 and 2016.

A total of 13,295 TAVR procedures were conducted over the 10-year period, increasing year-over-year from 66 in 2007 to 3,388 by 2016. By contrast, a total of 41,820 SAVRs were performed during this period and the numbers stayed roughly stable: 3,937 in 2007 and 4,187 in 2016.

As expected, patients undergoing TAVR procedures were typically older compared with those getting SAVR (81.2 vs 68.7 years) and at higher surgical risk (logistic EuroSCORE 20.1% vs 6.8%). Of note, while mean EuroSCORE remained relatively stable for SAVR patients over the study period, in TAVR-treated patients the estimated risk has declined significantly at a rate of approximately 0.5% per year.

Particularly striking in the UK data is the decline in in-hospital mortality rates with TAVR, which fell from 7.8% in 2008 to 2.0% in 2016. Over the same period, SAVR mortality rates fell from 2.1% in 2007 to 1.0% in 2016.

“That’s an interesting phenomenon that we hadn’t expected,” Cahill said. “Although we don’t see a change in the surgical risk score, it may be a change in surgical decision-making in terms of who [the surgeons] will take on, now that there is an alternate treatment strategy for patients who are really at the high end of [risk].” This likely has more to do with frailty and other comorbidities that are not reflected in the EuroSCORE, he added, speculating, “I think the care that’s now taken within the heart team about evaluation of patients has made it clear which patients we perhaps shouldn’t be operating on. Identifying who shouldn’t have a valve replacement is important as well and there is a lot more thought about that aspect than perhaps there used to be.”

Commenting on the study, session co-moderator Edgar Tay, MBBS, MMed (National University Heart Centre, Singapore), pointed to the fact that Germany and US registry data hint that TAVR is starting to overtake SAVR. By 2016, he continued, the UK TAVI Registry numbers are almost on par with surgery, showing the steepest rise after the intermediate-risk TAVR data was published. But, Tay continued, “what’s interesting is that the change in patient risk score over time is very, very gradual. That reflects how strictly you adhere to the heart team concept and guidelines.”

Cahill agreed, saying: “Reimbursement in the UK only comes after randomized controlled trial data. I think with PARTNER 2A and SURTAVI coming out recently, that’s already started the drive towards intermediate-risk populations, and as the lower-risk data comes out next year, I think that will start the ball rolling into a whole group of patients that up until now we’ve only really considered as surgical candidates.”

But data and reimbursement are only part of the equation in the United Kingdom, Cahill continued. “There’s a very established infrastructure for looking at the surgical delivery of care and changing the mindset, changing the heart teams’ approach to these patients will take time. It’s not just about having the data in place, it’s twofold: first the data coming to show that there is safety and efficacy . . . and secondly perhaps a slower change in logistics, mindset, decision-making, and physician referrals—being reassured that this is a genuinely safe procedure in lower-risk groups.”

Also commenting on the study following Cahill’s presentation, Stefano Salizzoni, MD, PhD (Università degli Studi di Torino, Italy), observed that the “most surprising thing” in these data is the near doubling of the number of patients with aortic stenosis now being treated.

“Where were these patients before?” Salizzoni asked. “That’s the most important thing that caught my attention. I think, probably, we also are lowering the indication for TAVR, even if [that is not reflected in] the EuroSCORE. There are a lot of patients that are so-called asymptomatic that once were not treated because of the high surgical risk, but now that they can undergo TAVI with nice results, we are treating more of these patients.”

Speaking with TCTMD following his presentation, however, Cahill said he didn’t think that lower-risk and asymptomatic aortic-stenosis patients make up much of the increase in who’s being treated, stressing again that the UK, because of it’s strictly controlled healthcare system, really sticks to the indications supported by randomized trial data. Cahill’s guess is that it is more the patients at the higher end of the risk spectrum, previously deemed inoperable, who are now getting referred for TAVR.

“We’re now 10 or 11 years out and the message is out: the people who are looking after these patients, the geriatricians and primary care physicians, they’ve all heard of TAVI. And rather than saying, ‘Well, you’re not fit for surgery, we’ll manage you with tablets,’ they now refer these patients to the heart teams and the heart teams are, quite rightly, offering TAVI,” he explained.

In terms of moving to asymptomatic aortic-stenosis patients, Cahill predicted that expansion into this group awaits results of trials like EARLY TAVR and EVOLVED. For now, he said, “if you present someone who is truly asymptomatic in a UK heart team meeting, I think everyone is still relatively conservative about that and I think they’d say: no, hold on. We would tend to watch and wait.”