Apixaban lowers valve thrombosis risk, does not affect ischemic events post-TAVR
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Apixaban reduced valve thrombosis at 90 days after transcatheter aortic valve replacement, but there was no difference in ischemic outcomes at 1 year vs. standard care, according to data from the ATLANTIS 4D-CT substudy.
“Apixaban reduces valve thrombosis in the majority of patients who undergo [TAVR] and do not have an established indication for anticoagulation,” Gilles Montalescot, MD, PhD, professor of cardiology at the Pitié-Salpêtrière Hospital in Paris, said during a presentation at the American College of Cardiology Scientific Session. “When this is compared to antiplatelet therapy, this effect is not observed vs. vitamin K antagonists in the cohort of patients with an indication for oral anticoagulation. The reduction of valve thrombosis at 3 months with apixaban in the cohort of patients, without an indication for oral anticoagulation, is not associated with clinical benefit at 1 year.”
The randomized, open-label ATLANTIS trial included 1,510 patients who underwent successful TAVR at 50 centers across France, Germany, Italy and Spain from 2016 to 2019.
As Healio previously reported, apixaban (Eliquis, Bristol Myers Squibb/Pfizer) was not superior to standard care for the primary composite endpoint of all-cause death, transient ischemic attack/stroke, MI, valve thrombosis, pulmonary embolism, deep venous thrombosis, systemic embolism or major bleeding at 1 year (HR = 0.92; 95% CI, 0.73-1.16). These findings were consistent among patients with an indication for oral anticoagulation other than TAVR (HR = 0.88; 95% CI, 0.66-1.17) and those without an indication for oral anticoagulation (HR = 1.02; 95% CI, 0.68-1.51; P for interaction = .57).
For this analysis, researchers evaluated whether the use of apixaban affected the incidence of valve thrombosis at 3 to 6 months post-TAVR compared with standard care. Patients were stratified according to whether patients had an indication of oral anticoagulation for a reason other than the TAVR procedure.
Thrombosis was measured based on marked reductions in prosthetic valve leaflet motion:
- grade 0, normal/unrestricted;
- grade 1, minimally restricted (< 25%);
- grade 2, mildly restricted (25% to 50%);
- grade 3, moderately restricted (50% to 75%); and
- grade 4, largely immobile (> 75%).
The primary endpoint was proportion of patients with at least one prosthetic valve leaflet with reduced leaflet motion of grade 3 or 4, or hypoattenuated leaflet thickening (HALT) of grade 3 or 4. In total, 762 CT scans for all endpoints were completed.
According to the presentation, apixaban reduced the occurrence of the primary endpoint among patients with no other indication of oral anticoagulation compared with standard care (OR = 0.54; 95% CI, 0.31-0.94; P = .0111).
Apixaban also reduced the likelihood of experiencing the secondary endpoint of reduced leaflet motion of grade 3 or 4 compared with standard care among patients not indicated for oral anticoagulation (OR = 0.12; 95% CI, 0.03-0.4).
Findings were similar for the outcomes of HALT 3 or 4 (OR = 0.5; 95% CI, 0.31-0.94) and presence of thrombus (OR = 0.51; 95% CI, 0.34-0.76), favoring apixaban over standard care among patients with no other indication for anticoagulation aside from TAVR.
Patients who experienced the primary endpoint at 3 months also experienced numerically more ischemic events at 1 year compared with those who did not, but this finding was not statistically significant (HR = 1.68; 95% CI, 0.82-3.44).
“We saw a trend to more clinical events at 1-year follow-up for patients with reduced leaflet motion of grade 3 or 4 or HALT of grade 3 or 4, but this difference is not significant,” Montalescot said during the presentation. “Of course, we may lack power in this analysis. We may need longer or more patients, but this trend is not significant.
“There was no superiority of apixaban vs. standard care for patients who were selected for this 4D CT scan substudy,” Montalescot said.
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Montalescot G, et al. Featured Clinical Research I. Presented at: American College of Cardiology Scientific Session; May 15-17, 2021 (virtual meeting).
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