Balloon-expandable, self-expanding TAVR valves associated with comparable long-term outcomes
Balloon-expandable and self-expanding transcatheter aortic valve replacement (TAVR) valves are associated with comparable patient outcomes after six years, according to a new long-term analysis published in the Journal of the American College of Cardiology.[1]
“With the expansion of TAVR indication to younger and lower-risk patients, there is the ongoing need to provide comprehensive long-term data on clinical outcomes and bioprosthetic-valve function on recent generation balloon-expandable and self-expanding valves,” wrote first author Zade Bihag, MD, a researcher with the department of internal medicine at University of Connecticut Health, and colleagues.
The study included data from nearly 2,500 TAVR patients who underwent treatment at a single high-volume facility. All patients underwent transfemoral TAVR, and any valve-in-valve cases were excluded.
While 1,685 patients received a balloon-expandable Sapien 3 or Sapien 3 Ultra valve from Edwards Lifesciences, another 776 patients received a self-expanding Evolut R, Evolut Pro or Evolut Pro+ valve from Medtronic. These are the two most commonly implanted TAVR valve platforms in the United States by a wide margin.
Propensity-score matching was used to deliver the most accurate side-by-side comparison possible; this resulted in groups of 683 balloon-expandable TAVR patients and 680 self-expanding TAVR patients. For the balloon-expandable cohort, the mean patient age was 82.2 years old, 52.3% were women, 95.9% were white and the mean Society of Thoracic Surgeons (STS) risk score was 7.9. For the self-expanding cohort, meanwhile, the mean patient age was 82.1 years old, 52.5% were women, 95.3% were white and the mean STS risk score was 7.9.
The only standout differences between the two groups after propensity-score matching were the higher rates of diabetes, prior myocardial infarction and prior coronary artery bypass grafting among patients who underwent balloon-expandable TAVR.
Overall, in-hospital outcomes as well as one-year outcomes were quite similar for the two groups. Permanent pacemakers implantation was less common with balloon-expandable valves, which is already an established difference between this generation of TAVR valves; Medtronic has specifically focused on lowering that rate with the most recent updates to its Evolut platform.
The median follow-up period for this study was 77 months. At the end of that time, all-cause mortality per a Kaplan-Meier survival analysis was 33.2% for balloon-expandable valves and 40.4% for self-expanding valves, close enough to not be ruled a significant difference.
However, two key differences were identified in the team’s research. First, balloon-expandable valves were linked to an increased rate of treatment for subclinical leaflet thrombosis (SLT). Second, self-expanding valves were linked to a higher incidence of transient ischemic attack (TIA).
Bihag et al. emphasized that that these SLT and TIA differences may not necessarily be because of the valve types these patients received.
“Prior studies have demonstrated an increased risk of SLT in patients with balloon-expandable versus self-expanding valves, larger TAVR bioprostheses, overexpanded TAVR valves, larger sinuses of Valsalva and valve-in-valve procedures,” the authors wrote. “Additionally, while SLT occurs more commonly in patients with elevated aortic valve gradients and in patients with prosthesis-patient mismatch, results from the RESOLVE and SAVORY registries suggest that the difference in the rates of SLT between valve types correlates more with a supra-annular versus an intra-annular design, rather than with a specific transcatheter heart valve.”
They had a similar message when touching on TIA risks:
“Apart from the possible impact of SLT, late transient ischemic attacks (TIA) following TAVR have been primarily attributed to underlying vascular disease and patient specific factors (advanced age, hypertension, diabetes, cerebrovascular disease, atrial fibrillation, peripheral arterial disease, chronic kidney disease), rather than being caused by procedural emboli at the time of the TAVR procedure. Additionally, increased TIA rates have been noted in patients with a history of a periprocedural stroke, in those with higher post-TAVR aortic valve gradients and in those not treated with oral anticoagulants. Of interest, increased TIAs post-TAVR in the current study were seen in the self-expanding cohort despite the higher incidence of diabetes, higher post-procedure AV gradients and more SLT in the balloon-expandable cohort.”
Another key takeaway was the fact that balloon-expandable valves were associated with higher rates of moderate (25% vs. 11.4%) or severe (9.1% vs. 3.1%) prosthesis-patient mismatch. It remains unclear at this time, they wrote, if this had a negative impact on clinical outcomes.
The group also noted that their research is associated with certain limitations, including the fact that it only includes retrospective data from a single facility. The lack of randomization is another limitation, as is the lack of data from an echocardiographic core laboratory.
Reviewing all of these findings, the research team concluded that the in-hospital, one-year and long-term outcomes for these two valve types were “similar” with a handful of notable exceptions.
“The differences in permamnet pacemaker rates between balloon-expandable and self-expanding patients will require ongoing surveillance of groups to continue to monitor comprehensive long-term data on clinical outcomes and bioprosthetic valve function,” the authors wrote.
Click here to read the full study.
Michael has more than 18 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.