Post-TAVR SLT risk does not differ with edoxaban or DAPT

The risk of subclinical valve leaflet thrombosis (SLT) following transcatheter aortic valve replacement (TAVR) did not differ regardless of whether patients received edoxaban or dual antiplatelet therapy (DAPT) post-surgery, according to results of the ADAPT-TAVR* trial.

“The overall incidence of SLT on computed tomography (CT) scans was less frequent with the edoxaban therapy than with the DAPT therapy, although it did not reach statistical significance,” presented principal investigator Dr Duk-Woo Park from the Asan Medical Center, Seoul, South Korea, at ACC.22.

The population of this multinational, open-label trial were 220 adults who successfully underwent TAVR and had no indication for long-term oral anticoagulants. They were randomized 1:1 to receive the novel oral anticoagulant edoxaban (30 or 60 mg QD depending on underlying renal disease, body weight, or use of P-glycoprotein inhibitors) or the DAPT combination of aspirin plus clopidogrel for 6 months. The patients underwent four-dimensional cardiac CT 6 months post-TAVR.

In the intention-to-treat (ITT) population, there was a numerical but not statistically significant difference in the risk of SLT among patients assigned to edoxaban vs DAPT at 6 months (9.8 percent vs 18.4 percent; risk ratio [RR], 0.53, 95 percent confidence interval [CI], 0.26–1.09; p=0.076). [ACC.22, abstract 22-LBCT-15759-ACC]

The risk of SLT was also reduced with edoxaban vs DAPT in the per-protocol population (9.1 percent vs 19.1 percent; RR, 0.48, 95 percent CI, 0.23–0.99; p=0.047).

Magnetic resonance imaging showed no significant difference between the edoxaban and DAPT groups** in terms of presence of new cerebral lesions (25.0 percent vs 20.2 percent; p=0.40), total number of new lesions (median 1 in each group; p=0.85), and total volume of new lesions (median 36.6 vs 43.9 mm³; p=0.88).

There was also no significant difference between edoxaban and DAPT recipients with regard to the proportion of patients with worsening score on the National Institutes of Health Stroke Scale (5.0 percent vs 3.7 percent; p=0.74), worsening Modified Rankin Scale score (2.0 percent vs 0.9 percent; p=0.69), and worsening of Montreal Cognitive Assessment score (30.0 percent vs 22.2 percent; p=0.20).

“We saw no correlation between the number of occurrences of detectable SLT and the number of new signs of blood clotting in the brain or changes in cognitive function,” Park pointed out.

There were three and two deaths in the edoxaban and DAPT groups, respectively, at 6 months (hazard ratio [HR], 1.48), and two ischaemic strokes in each group (HR, 1.05). Thirteen patients in the edoxaban group and 15 in the DAPT group experienced bleeding events, and 17 and 14, respectively, were re-hospitalized.

“The key messages from this study are that SLT has not been proven to affect clinical outcomes for patients undergoing valve replacement and that in patients in whom SLT causes no symptoms or complications, its presence should not dictate the type of antithrombotic therapy that patients receive following the implantation of an artificial heart valve,” said Park.

“Additionally, these findings do not support the routine use of CT scans to detect SLT,” Park added.

Park noted that the findings may not apply to patients who have an indication for oral anticoagulants, who make up approximately one-third of patients who have undergone TAVR. Furthermore, the follow-up period was relatively short. “[As such,] the long-term effect of leaflet thrombosis or different antithrombotic strategies on bioprosthetic valve durability is still unknown.”

*ADAPT-TAVR: Anticoagulant versus Dual Antiplatelet Therapy for Preventing Leaflet Thrombosis after Transcatheter Aortic Valve Replacement  

**ITT population