Slight Gain in Stroke Protection Seen With DAPT in ViV TAVI

In patients who require a valve-in-valve (ViV) transcatheter procedure for a failed aortic bioprosthesis, the choice of antiplatelet therapy has little bearing on major ischemic and bleeding outcomes at 1 year, although dual antiplatelet therapy (DAPT) may lower the risk of stroke, new data show.

In the nonrandomized study of 278 patients from Italy, use of DAPT resulted in more minor bleeding (VARC 3 type 1) than did single antiplatelet therapy (SAPT), with no difference in major bleeding between the two regimens

The study’s authors, led by Francesco Bendandi, MD (RCCS Azienda Ospedaliero-Universitaria di Bologna, Italy), note that while SAPT is recommended over DAPT based on the potential for increased bleeding and lack of benefit on ischemic outcomes, as seen in the POPULAR TAVI trial, clarity on the best approach in ViV TAVI remains elusive due to lack of studies in this population.

“Theoretically, a more intense antithrombotic treatment could prevent embolic events caused by valve thrombosis, particularly early after implantation, when device endothelization is incomplete,” Bendandi and colleagues write in their paper, published recently in JACC: Cardiovascular Interventions.

The rate of stroke was 0.6% at 1 year in patients who received DAPT after a ViV TAVI procedure compared with 4.6% in those treated with SAPT (P = 0.031). Of the five strokes in the SAPT group, two occurred on the day of the procedure, with the other two occurring on days 16, 217, and 303. In the DAPT group, the single stroke that was seen occurred on day 27.

Bendandi and colleagues also conducted a sensitivity analysis that excluded the two periprocedural strokes in the SAPT group to account for the possibility these were caused by intraprocedural embolization. With those excluded, the incidence of stroke between the DAPT and SAPT groups was 0.6% and 2.7%, respectively at 1 year (P = 0.152).

Commenting for TCTMD, Michael Reardon, MD (Houston Methodist DeBakey Heart & Vascular Center, TX), agreed that there aren’t much data on antiplatelet options for patients after ViV TAVI other than what has been demonstrated to be best in RCTs.

“So far, the consensus seems to be that if you add an oral anticoagulant you bleed more and it doesn’t help. Nobody’s ever shown that adding a second platelet makes any real difference,” he said.

DAPT’s lack of impact on the primary outcome of CV death, stroke, and MI in the study doesn’t inspire confidence that DAPT is needed in this population, a position that is further bolstered by the results of the sensitivity analysis, said Reardon.

“To me, it’s basically a negative trial that is hypothesis-generating at best, and is not likely to change practice,” he added.

Hints of Early Degenerated Valves

The study included patients treated with ViV TAVI followed by DAPT (n = 165) or SAPT (n = 113) at 10 centers in Italy between January 2008 and July 2023. Those in the DAPT group were slightly older and more likely to have hypertension, obstructive CAD, and higher surgical risk according to STS score than those in the SAPT group. There were no major differences in the type of failed surgical or transcatheter bioprosthetic valve or failure mechanism between the DAPT and SAPT groups. The trial included more than a dozen TAVI devices—both self-expanding and balloon-expanding bioprostheses—that are available in Europe.

The incidence of MACCE at 1 year was 5.6% in the DAPT group and 7.5% in the SAPT group (P = 0.572). Other individual clinical endpoints, with the exception of stroke, also were similar between groups.

One-Year Outcomes After ViV TAVI

Despite the lack of difference in clinical endpoints, Bendandi and colleague say DAPT may still have a role to play in this patient population and point to the acceptable risk profile, including the lack of difference in major bleeding (VARC 3 type 2-4) compared with SAPT, which is in line with the findings from POPULAR TAVI.

While the numbers in the trial are small, the group says the greater absolute incidence of premature valve degeneration at 1 year in the SAPT group may be a relevant observation, coupled with a small but significant increase in mean transvalvular gradients observed in the SAPT patients, but not in those on DAPT.

“Although our study is not conclusive, the high number of early degenerated valves confirms that valve-in-valve patients represent a population more susceptible to this event and the significant gradient increase in patients treated with SAPT suggests that subclinical valve thrombosis may represent the underlying mechanism,” they write. “However, systematic assessment of subclinical thrombosis with CT scan would be necessary to test this hypothesis.”

According to Reardon, more clarity also is needed in the form of a randomized trial. This would get rid of the lingering question of how the choice of antiplatelet regimen was made after a ViV TAVI procedure, something that was not accounted for in the study.

“If there is more calcium on the valves that may influence a decision to treat them a little more intensively than other people getting this procedure,” he said. “So, if they’re making conscious choices between one or the other that’s a pretreatment bias that you can’t propensity match out.”

Another confounder in this study, Reardon added, is the mixture of patients with failure of surgical and transcatheter bioprosthetic valves—two potentially very different populations based on their initial treatment eligibility.