US Aortic Valve Trends in Older Patients Hint at Better Outcomes, Access

Among older patients, the advent of TAVI coincided with declines in mortality, readmission, and more probability of being discharged home, as well as a substantial increase in AVR procedures in the 65 and over population between 2012 and 2019, a new Medicare analysis shows.

Makoto Mori, MD (Yale School of Medicine, New Haven, CT), the study’s lead author, told TCTMD that the Medicare database represents a well-defined population for understanding how TAVI’s arrival impacted the overall balance in high- and intermediate-risk patient populations and outcomes between the complementary transcatheter and surgical procedures.

“What our paper showed was that the characteristics of people who had access to AVR technology hadn't changed drastically after the initial dramatic uptake of TAVR in the highest-risk strata, and the rapidly increasing volume of total AVR would suggest that it has improved access,” he said.

The last decade has seen TAVI emerge as a disruptive technology in AVR. An earlier Medicare analysis of patients with aortic stenosis treated from 2011 through 2014 found that isolated SAVR rates dropped as TAVI volumes increased, with a corresponding decrease in comorbidities among surgical patients. In 2020, an analysis from the Society of Thoracic Surgeons/American College of Cardiology TVT Registry of more 276,316 TAVI patients reiterated that transcatheter has become the dominant form of valve replacement in a fairly short period of time, but how this has impacted SAVR numbers and outcomes remains an evolving picture.

Mori said looking at all AVR procedures combined, as their new Medicare study does, adds a slightly different and important perspective.

In an accompanying editorial, Sreekanth Vemulapalli, MD (Duke University School of Medicine, Durham, NC), and Vinod H. Thourani, MD (Piedmont Heart Institute, Atlanta, GA), say analyzing TAVI and SAVR in isolation, which is typically done as a result of the different registry data available, “effectively clouds our ability to recognize simple trends in overall AVR care.” This, they add, is a public health and health policy problem in light of concerns over disparities in geographical distribution, access for racial and ethnic minority groups, and quality issues in TAVI care.

“In the face of the relative clinical maturity of TAVR, there remain a significant number of societally important public health questions concerning the real-world implementation and provision of AVR care in the United States,” they write.

Reassurance of Better Outcomes

For the study, published in the Journal of the American College of Cardiology, Mori and colleagues examined Medicare data on 181,359 hospitalizations for TAVI and 221,312 hospitalizations for SAVR from 2012 to 2019.

There were some unusual trends. Median interquartile age range remained similar between the two time periods (77 to 78 years), despite declining mean age in both the TAVI and SAVR groups. Also counterintuitively, as some comorbidities decreased in TAVI-treated patients and surgical patients, the overall AVR group saw a rise over time in unstable angina, stroke, renal failure, and dementia.

Total AVR procedures increased from 80,241 in 2012-13 to 120,783 in 2018-2019, driven by a more than doubling in the number of TAVI procedures after indication expansion (from 14,078 to 30,522). By contrast, SAVR procedure numbers declined over this same window (from 66,163 to 42,055).

The increase in TAVI volume from 2012 to 2019 was accompanied by declining rates of 30-day and 1-year mortality across all procedures—apart from 30-day mortality post-SAVR, which held steady—as well as a decrease in readmission within 30 days over the same time period.

Changes in Outcomes, 2012-2019: HR (95% CI)

Median length of stay was shorter for TAVI, SAVR, and AVR as a whole in 2019 compared with 2012: 2 versus 6 days for TAVI, 7 versus 8 days for SAVR, and 3 versus 8 days for AVR as a whole. Discharge to home without home care increased in the TAVI population over time, from 28.4% in 2012 to 69.9% in 2019. Among SAVR patients, discharge status remained mostly unchanged, with 32.8% requiring home care in 2012 and 37.2% in 2019. In all AVR, home discharge more than doubled from 24.2% to 54.7%.

Mori and colleagues say the decrease in TAVI mortality and the increase in patients being discharged home “likely relate to the increasing application of TAVR to lower-risk patients, increased operator experience, and improvements in device technology.” To TCTMD, Mori said it is reassuring that the shift from SAVR to TAVI in older patients did not worsen SAVR outcomes, and that AVR patients as a group showed continuous improvement over time. Another finding that may be especially reassuring for payers, he added, is that increase in discharge to home in both TAVI and SAVR suggests no compromise of functional outcomes, which can be important in deciding on treatment options for older adults.

The ‘Will Rogers Phenomenon’

The apparent paradoxes in both the age and comorbidity patterns for TAVI/SAVR separately versus overall AVR fall into the category of the “Will Rogers phenomenon,” say both Mori and the editorialists. Named after the American humorist, the phenomenon refers to the ability of individual parts to suggest different trends than the combined whole.

“When you look at just TAVR and SAVR in an isolated fashion, it appears that the age and prevalence of comorbidities declined consistently over the years, but that really is not the case,” Mori noted. It makes sense, he added, in the context of knowing that the highest-risk SAVR patients migrated to TAVI, which made them either average risk or low risk for that procedure, but they were still high risk for SAVR.

Vemulapalli and Thourani say that while this analysis, looking at the whole of AVR, is a good starting point for filling remaining gaps in knowledge, they would like to see “cardiologists and cardiac surgeons, and their respective professional societies, link the existing STS Adult Cardiac Surgery database and the Transcatheter Valve Therapies registry, along with administrative claims data.” Doing this, they add, “would facilitate needed pragmatic, prospective studies and retrospective research to answer pressing implementation and health policy questions specific to this new, mature phase of AVR care in the United States.”

Mori said he would support that collaboration. “I think that would be a great thing to do because long- term data are really in need of discussion right now with lower-risk TAVR coming on board,” he concluded.