TAVI Proficiency Doesn’t Spell Success for M-TEER at Large US Sites

High-volume TAVI centers also tend to do a lot of mitral transcatheter edge-to-edge repair (M-TEER) procedures, but there is little correlation between procedural and short-term outcomes of TAVI and M-TEER at centers capable of handling both interventions, according to a registry analysis.

For multiple outcome measures, including in-hospital and 30-day mortality, just 1 in 9 hospitals had a similar ranking for TAVI and M-TEER, with most hospitals having discordant track records for the two valve interventions, report investigators.

“There’s been this rapid explosion in terms of this broad umbrella term of ‘structural heart interventions,’” lead investigator Dharam Kumbhani, MD (UT Southwestern Medical Center, Dallas, TX), told TCTMD. That’s led to some centers being designated as “centers of excellence” based on an underlying assumption that proficiency and skill in one procedure would be linked to high-quality treatment of another valve, he said. 

That’s not borne out by these data, said Kumbhani.

“Fundamentally, there's some overlap in the procedures, just in terms of maybe large-bore access management, but otherwise the skills that you need are very different,” said Kumbhani. “These are very different procedures and you're really comparing apples to oranges. . . . They shouldn’t be considered similar from a training standpoint or from a proficiency standpoint.”

Mohamad Alkhouli, MD, Juan Crestanello, MD, and Charanjit Rihal, MD (all from Mayo Clinic, Rochester, MN), in an accompanying editorial, come to the same conclusion, observing that many sites excelled in one procedure, but underperformed in the other. They point out that TAVI is now a “mature and widely adopted procedure” but that transcatheter mitral valve therapies remain the domain of specialized centers, with less than 60% of TAVI sites in the US performing M-TEER.

Centers of Excellence

In 2019, an expert consensus statement from multiple US organizations, including those representing surgeons and interventional cardiologists, proposed a tier-based system designating level 1 hospitals as comprehensive valve centers with a high level of expertise in all valve therapies, including complex or specialized procedures. A similar approach has been adopted in Europe, with centers of excellence capable of performing all approved surgical and percutaneous procedures, including TAVI and M-TEER.

This has also impacted training pathways, Kumbhani noted. “These are the centers that have the fellowships, where a lot of the people are getting trained. So that’s why, for multiple reasons, we wanted to study this systematically using TVT data: are the centers that are doing TAVRs well, the high-performing centers, are those the same as those doing [M-TEER] well?”

The researchers turned to the Society of Thoracic Surgeons/American College of Cardiology (STS/ACC) TVT Registry to assess the relationship between TAVI and M-TEER hospital volumes and outcomes and to identify variables that predict M-TEER outcomes separate from TAVI outcomes.

Between 2013 and 2022, 384,394 patients underwent TAVI and 53,274 were treated with M-TEER at 453 US sites. The median annual volume was 93.6 TAVIs and 18.8 M-TEERs performed at each center.

High-volume TAVI sites were more likely to also be high-volume M-TEER centers (Spearman coefficient = 0.48). For both procedures, in-hospital mortality was low and did not differ by center volume. In-hospital mortality for TAVI was 1.6%, 1.7%, and 1.6% at low-, mid-, and higher-volume centers, and 2.3%, 2.1%, and 2.0% for M-TEER at low-, mid-, and higher-volume centers, respectively.

When it came to both TAVI and M-TEER outcomes, however, there was a high degree of variability between sites. Across multiple different performance outcomes, including in-hospital and 30-day mortality, 30-day procedural success, in-hospital complications, and a 30-day composite endpoint, just 13% to 15% of hospitals had the same level of performance with TAVI as with M-TEER.

Stratified by decile, 50% to 58% of hospitals were within two deciles of each other in terms of overall performance, while 77% to 82% were within four deciles. More than one-third had even larger variations in performance.    

In a model aimed at identifying site-level predictors of M-TEER outcomes, one that accounted for differences in patient case mix, the 30-day composite endpoint varied across US centers by a median of 57%. Put another way, two statistically identical patients would have an approximately 60% difference in the 30-day endpoint at two random US sites, according to investigators.

Looking for Operator-Level Data Next

Kumbhani said they initially expected to see overlap in performance between sites capable of performing TAVI and M-TEER. In terms of why there was such discordance, he hypothesized that some hospitals now have completely separate teams for each procedure, with one team possibly outpacing the other.

Most places, however, would still have a “fair amount of overlap between the teams,” he said. “It’s not completely segregated.”

Another explanation might be that operators at some centers are still learning M-TEER techniques, he said, pointing out that the median annual volume was significantly lower relative to TAVI. “It’s easier to get more proficient with TAVI quickly,” said Kumbhani, adding that a 2019 paper published by Adnan Chhatriwalla, MD (Saint Luke's Mid America Heart Institute, Kansas City, MO), and colleagues in JACC: Cardiovascular Interventions suggested it takes at least 50 M-TEER procedures before operators are comfortable and achieving optimal outcomes.

Interventional cardiologist Saurav Chatterjee, MD (Maimonides Medical Center, New York), who wasn’t involved in the new study, told TCTMD that there is some overlap in terms of technique and skill sets for TAVI and M-TEER, but they are inherently different procedures, each with its own nuances.

Still, “operators can be quite capable with enough experience to be proficient in both procedures,” he said.

One of the limitations of the present analysis, which is not meant as a criticism, is that it is focused on sites rather than operators, said Chatterjee.

“Broadly speaking, there is a significant variation and variability in outcomes with different volumes and other factors with individual operators,” he said. “The other question, which is related: is there then a remedy, where if it’s just procedural technique or another set of factors, that can help differentiate an operator’s performance?”

Being able to identify predictors of poorer outcomes at the operator level would help address some of discordance seen in the present site-level analysis, said Chatterjee.

“I think everyone is trying to do the best for their patient, but if there was something that I could learn from my peers, whether it be at the same center or neighboring center of excellence, [it] would potentially provide a great incentive and a great opportunity to elevate the field as a whole,” Chatterjee said.

Chatterjee noted that previous studies have shown no association between inpatient PCI volumes and TAVI or M-TEER outcomes, findings that questioned whether the minimum PCI requirements are necessary to establish solid TAVI or M-TEER programs.   

As to whether sites should be separated based on their expertise with each valve, such as a dedicated mitral valve center of excellence, Kumbhani said one option that’s been proposed is the creation of tiered systems of care based on disease. Before that, though, researchers need to take a closer look at operator-level data.

“There’s still a lot of heterogeneity on the mitral side,” he said. “We're trying to drill down more into how much of that is driven by operators, how much of that is driven by the hospital itself. That may have a bearing on, or help further inform, this ‘centers of excellence’ discussion.”