Patients with severe aortic stenosis (AS) who undergo transcatheter aortic valve replacement (TAVR) enjoy a minor but significant sustained health benefit that isn’t mirrored in patients who opt for surgical AVR (SAVR), according to research reported at TCT 2019 in San Francisco.
TAVR has evolved over the years, morphing from a surgical alternative meant exclusively for high-risk AS patients to an option for lower-risk candidates, and in the process it’s forced a paradigm shift in interventional cardiology. But, presenting her team’s PARTNER 3 results, Suzanne J. Baron, MD, MSc, emphasized the fact that there’s still a lot we don’t know about the transcatheter approach.
A handful of clinical trials have proven TAVR’s safety and efficacy compared to SAVR, but researchers still lack an understanding of the long-term health benefits of TAVR. Baron et al. used PARTNER 3 data to study the relationship between TAVR or SAVR and late health status in AS patients at a low surgical risk.
The baseline characteristics of the analytic cohorts were similar, with patients in both the TAVR and SAVR subgroups reporting an average STS risk score of 1.9% and mild impairment in health status that translated to a mean Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary (OS) score of 70. That score corresponds to New York Heart Association (NYHA) Class II symptoms, consistent with participants’ relatively low rates of comorbidities like peripheral artery disease and prior stroke.
Considering the KCCQ OS score as a primary endpoint, Baron and the PARTNER 3 investigators found a “persistent—albeit small” late benefit in disease-specific health status with TAVR patients.
“Not surprisingly, patients who underwent TAVR demonstrated substantially improved health status at one month,” Baron said. “However, in contrast to prior studies, at six months and 12 months the benefit of TAVR over surgery persisted, although the magnitude was smaller.”
Baron said that by 12 months, patients in both the TAVR and SAVR groups had achieved a KCCQ OS score improvement of about 19 points, representing a large benefit in health outcomes. At one year, the absolute risk difference was 5.2%, driven by the fact that more TAVR patients saw an improvement of 20 points or more in their KCCQ OS score compared to SAVR patients.
Baron also reported that patients with NYHA Class III/IV symptoms at baseline benefited more from TAVR than those with Class I/II symptoms.
“This finding suggests it’s the patients with worse functional impairment at baseline who may be that subset of patients on the cumulative responder curves who gained better health status outcomes with TAVR compared with surgery in the low-risk population,” she said. “Although the late health status benefit of TAVR was numerically small, it represents a subset of individual patients who derived a substantially greater health status benefit from TAVR than SAVR.”
A small subgroup analysis of patients considered “frail” suggested those people also might benefit more from TAVR than the general AS population.
Asked about the financial differences between high-, intermediate- and low-risk TAVRs, Baron said procedures have become “substantially more cost-effective” the lower a patient’s risk. In some cases, intermediate-risk patients who undergo TAVR are saving money, she said.
Baron attributed much of the increasing cost-effectiveness of TAVR to decreasing rates of procedural complications and decreasing lengths of hospital stay, which have fallen dramatically over the years. High-risk patients could once expect a 10-day stay in the hospital; in PARTNER 2 that dropped to between four and six days. Now, it’s even lower.
“I would imagine—although I don’t know—that I would expect in the low-risk population we will see continued benefits from a cost perspective,” Baron said. “But that analysis is yet to be done.”