TAVR Deterioration Rare Over 5 Years: Meta-analysis
Stronger and longer-term evidence is needed to allay worries over what durability might be for younger TAVR patients, researchers say.
Durability—or the lack thereof—of bioprosthetic valves continues to be a hot topic, especially as TAVR is being explored as an option for ever younger patients. A new meta-analysis published online last week in Heart offers at least some reassurance that the deterioration of the transcatheter devices is “probably an infrequent event within the first 5 years,” researchers say.
Specifically, lead author Farid Foroutan, MD (McMaster University, Hamilton, Canada), and colleagues estimated a pooled incidence of 28 structural valve deterioration (SVD) cases per 10,000 patient-years. But given that in surgical AVR “rates of deterioration increase substantially at 10 years, and even more at 15 years,” further study in patients with longer life expectancies is required, urge the investigators, who last year released a set of rapid recommendations for TAVR decision-making that stratified advice based on age.
“To the best of our knowledge this is the first systematic review to address this concern of structural valve deterioration,” the study’s senior author, Rodrigo Bagur, MD (Western University, London, Canada, and Keele University, Stoke-on-Trent, England), told TCTMD. He pointed out that the patients included in the analysis represent the “initial cohort” of TAVR, and as such they are “high risk and very elderly. And that’s why we can’t obtain longer follow-up.”
Moreover, the first-generation TAVR devices did not have anticalcification properties, Bagur added. “This technology has [since] been incorporated from the surgical proprostheses into the transcatheter [realm],” he said. Thus, while the current findings are reassuring, there is still uncertainty.
Most Cases Tied to Valve Restenosis
Foroutan et al combined data from 13 observational studies including 8,914 patients that were published between 2002 and September 2016. Median follow-up among the studies ranged between 1.6 and 5 years.
Though the pooled incidence of SVD was 28.08 per 10,000 patient-years, it ranged between 0 and 134 per 10,000 across the studies. However, results were consistent between the studies that did and did not use the VARC-2 definition, and between those having median follow-up durations above and below the threshold of 4 years. In the five studies that reported on the cause of SVD, 58% of cases were related to valve restenosis, 39% to regurgitation, and 3% to mixed factors.
Only three patients in the data set underwent transcatheter valve-in-valve treatment, for a rate of 12%. Many patients “may not have undergone intervention either because they were too old, too frail, or simply had died before any intervention or diagnosis of structural valve deterioration,” Bagur pointed out.
Contrary to expectations, even after adjustment for potential confounders, patients with self-expanding valves experienced 6.4 more cases of SVD per 10,000 patient-years compared with those treated with balloon-expandable valves (P = 0.0366).
“Prior speculations suggested that balloon-expandable valves result in a traumatic effect on the leaflets and potential structural damage on crimped leaflets that may impact valve durability,” Bagur noted, stressing that the researchers’ finding of increased risk with self-expanding valves has “low credibility” as it comes from a post hoc comparison and was inconsistent across studies.
Additionally, there were signs that lack of anticoagulation at discharge was linked to higher risk, but this association was no longer apparent after adjustment.
Foroutan F, Guyatt GH, Otto CM, et al. Structural valve deterioration after transcatheter aortic valve implantation. Heart. 2017;Epub ahead of print.
- Foroutan and Bagur report no relevant disclosures.