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A panel evaluating evidence to revamp Medicare's requirements for reimbursement of transcatheter aortic valve replacement (TAVR) came up with widely varying conclusions on whether procedural volume should continue to be the basis.
Of the voting questions, the average level of confidence in the evidence hovered in the intermediate range for nearly all, with mean scores in the 3 to 4 range on a 5-point scale. However, individual questions saw both 1 or 2 and 4 or 5 answers on all.
The greatest confidence was expressed that there was sufficient evidence that a certain threshold must be met before starting to perform TAVR -- of structural heart disease procedural volumes for the principle interventional cardiologist on a TAVR heart team and of either TAVR or surgical aortic valve replacement (SAVR) volumes for the principle cardiovascular surgeon on the team.
The lowest level of confidence, with a mean score of 3.11, came in for whether the benefits of meeting procedural volume requirements to begin a TAVR program outweighs the harm of limiting access to TAVR to only hospitals that meet volume requirements.
Access to TAVR was a big concern expressed by the panel, noting particularly low rates for minorities and women, although many said they saw the volume requirements keeping TAVR out of reach for smaller, rural, and underserved area hospitals as only part of the problem.
The Centers for Medicare and Medicaid Services (CMS) will take the panel's comments into consideration as it shapes the due out by June 25, 2019.
The purpose of the meeting was to consider whether having volume requirements, as initially set in 2012, is supported by scientific evidence, without discussing what specific numbers these should be, noted Sarah Fulton, MHS, presenting for CMS. It was in response to a formal request challenging procedural volume requirements and calling for coverage to be based on quality outcomes instead of non-TAVR procedural volumes.
Are PCI and SAVR Volume Requirements Needed?
Peter Pelikan, MD, director of interventional cardiology at the Pacific Heart Institute in Santa Monica, California, who initiated that formal request, argued that programs' and operators' quality, not volume, should be the determinant of CMS coverage of TAVR. "The time is right to modernize."
For example, he cited a of more than 18,000 consecutive percutaneous coronary interventions (PCIs) early in the stent era across 165 operators and 14 hospitals showing no relationship between operator volume and in-hospital mortality, although there was a "mild" correlation with major adverse cardiovascular events. A more contemporary also showed no correlation between PCI volume and mortality across 93 hospitals.
Analysis of the MEDPAR database of Medicare patients for 2012-2016 didn't replicate the relationship between current or prior volume of either surgical aortic valve replacement or percutaneous coronary intervention and TAVR in-hospital mortality, said Martin Leon, MD, of Columbia University/New York Presbyterian Hospital in New York City, speaking on behalf of the medical device trade association AdvaMed.
Pelikan acknowledged that operator training is key, but suggested that other structural heart procedures should be included in the volume totals, such as Watchman, MitraClip, patent foramen ovale closure, and so on.
"Individual operator and institutional requirements are not as important as the aggregate requirements that define the infrastructure necessary to provide quality care," noted Ted Feldman, MD, speaking on behalf of SCAI at the meeting. He said he's convinced that a PCI volume requirement is important, not least for handling the "not uncommon" catastrophic complications as well as in handling the complex coronary artery disease seen in at least 20% of these patients.
For the voting panel, the SAVR requirements were seen as both a safety issue, albeit with mixed levels of importance.
Panelist Smadar Kort, MD, director of the Valve Center at New York's Stony Brook University Hospital, said she voted a 5 for confidence in the need for SAVR requirements to start a TAVR program, because it demonstrates the center knows how to take care of sick patients with severe aortic stenosis. If something goes wrong, patients need access to quality SAVR with a team, including nurses and technicians, who have experience, she said.
But for the same question, panelist Sandra Lewis, MD, director of research and prevention at the Northwest Cardiovascular Institute in Chicago, voted 3. "I didn't see a lot of evidence today," she said, but still, "I have this sense that somebody should know their way around the aorta to be involved in a TAVR startup."
Are TAVR Volume Requirements Necessary?
The TVT Registry data shows the relationship is real, argued Carl Tommaso, MD, and Joseph Bavaria, MD, speaking on behalf of the American Association for Thoracic Surgery, American College of Cardiology, Society of Cardiovascular Angiography and Interventions (SCAI), and Society of Thoracic Surgeons.
They argued for a site volume requirement of at least 50 TAVR cases per year, citing data from the TVT Registry. The current requirement to maintain an existing program is a combined total of 20 TAVRs in the prior year between the cardiovascular surgeon and interventional cardiologist combined (or 40 in 2 years).
In that database in 2016, lower TAVR site volume was associated with a higher risk-adjusted ratio of observed-to-expected 30-day mortality. Notably, 96% of sites with a ratio over 2, which they called concerning, had a volume under 100 per year. A root cause of death analysis showed an exponential decay relationship between 50 and 100 cases.
Further analysis of the registry data through 2017, dividing centers by case volume of 50 again showed that hospitals falling under this threshold had higher mortality.
Leon pointed out that the TVT Registry data on the latest generation of devices Evolute R/PRO and Sapien 3 has shown no significant correlation between in-hospital or 30-day mortality and TAVR volume.
When it came time to vote, though, the panel didn't seem thoroughly convinced by either side.
Daniel Ollendorf, PhD, of the Institute for Clinical and Economic Review, said he went into the meeting feeling that he needed to be convinced that the volume-outcome relationships consistently seen across complex procedures didn't exist. But while he said that he remained convinced of it, "volume as the only surrogate for quality also doesn't make sense to me."
Guest panel member Patrice Desvigne-Nickens, MD, of the National Heart, Lung, and Blood Institute, said she found it frustrating. "Of course, you have to have some experience to have good outcomes," she said. But volume requirements impair access, and worse than low volume is not even having access, she said. "I hope there's an opportunity to point out just how thin, even if necessary, volume is to assess this breakthrough technology."
The Low-Volume Center Conundrum
In that Evolute data, some low-volume centers outperformed high-volume centers, while some high-volume centers achieved poorer outcomes than low-volume centers. Leon noted that of the centers doing TAVR now that wouldn't meet the 50 TAVR cases-per-year threshold proposed by the cardiology societies, 70% had 0% in-hospital mortality in 2016.
However, anything below 50 TAVR cases per year at a site can't be reliably statistically assessed for quality, Bavaria and Tomaso argued. Rather than close down such program, they would need a robust quality assessment program, regular review of structure and process, close monitoring of patient selection, and a review of outcomes of every case, they said.
More than 84% of current programs in existence for at least 2 years meet this 50 case per year threshold, Tomaso said.
The concern was raised that these smaller programs are important for access to care, particularly in rural settings and for minorities and those who refuse or are unable to travel to larger, higher-volume centers.
However, the lower rate in African Americans is something that has been seen across cardiology procedures and has persisted at least from the time bypass surgery started, said panelist Aloysius Cuyjet, MD, MPH, of HealthCare Partners in Garden City, New York. The answer is not to increase the number of centers doing TAVR, he said. "It's more fundamental to how the healthcare system works."
Potential Solutions
Leon called for shifting to TVT Registry mortality-based quality measures immediately, rather than waiting for a gradual 7-year shift as proposed by the cardiology societies. Then these could evolve into validated outcome measures, perhaps a composite of hard events and quality of life measures, over time, he suggested.
There is high variability in outcomes across all volume categories, which is a top priority for the field to figure out in the next 5 years, Bavaria and Tomaso emphasized. Risk-adjusted composite quality measures are still under development, but components could include risk-adjusted in-hospital and 30-day mortality as well as stroke or transient ischemic attack, vascular complications, pacemaker implantation, and quality of life.
Cardiac surgery has moved to composite measures as a more powerful tool, especially at lower volumes, noted speaker David M. Shahian, MD, chair of the Society of Thoracic Surgeons' Council on Quality, Research, and Patient Safety. And TAVR is moving that way too, he said.
There is broad consensus that if there were other quality measures already available, those would be preferred, said Naftali Zvi Frankel, the patient and consumer advocate on the panel. But they aren't available, especially not publicly for patients, he said. Until better alternatives are available, volume is all there is.