Resolution of leaflet thrombosis under anticoagulant therapy in patients after transcatheter aortic valve implantation: influence of prosthesis type and size

Abstract

Abstract Introduction Leaflet thrombosis can frequently be identified by computed tomography angiography (CTA) in patients after transcatheter aortic valve implantation (TAVI). Oral anticoagulation is assumed to lead to resolution of thrombosis. We analyzed the resolution of leaflet thrombosis after TAVI by anticoagulant therapy in serial CTA and assessed the influence of prosthesis type. Methods Consecutive TAVI patients who underwent CTA follow-up were screened and individuals with leaflet thrombosis on CTA (defined by the presence of hypo-attenuated leaflet thickening, HALT) in whom oral anticoagulation was initiated and who underwent follow-up CTA were included. The type of anticoagulation was according to physicians' discretion. We assessed the resolution of HALT and compared patients with and without resolution of HALT regarding prosthesis type, prosthesis diameter and type of anticoagulation. Results Out of 395 patients screened for participation, 36 patients (mean age 80±7, 67% men) with leaflet thrombosis underwent follow-up CTA at a medial interval of 3 months (IQR: 3; 5.75 months) after anticoagulation was initiated. 36 patients received either vitamin-K antagonists (n=28, 78%) or Factor-Xa Inhibitors (n=8, 22%). A total of 22 (61%) balloon-expandable and 14 (39%) self-expandable transcatheter aortic valves were implanted. Nominal prosthesis diameter was 23, 25, 26, 27 and 29 mm in 7 (19%), 1 (3%), 10 (28%), 7 (19%) and 11 (31%) patients, respectively. 30 patients (83%) with anticoagulation showed resolution of HALT, whereas persistent HALT was detected in 6 patients (17%), of whom 1 patient with balloon-expandable and 5 patients with self-expandable valve. No difference was seen in duration of anticoagulation between patients with and without resolution of HALT (p=0.984). In univariate analysis, prosthesis type (balloon-expandable vs. self-expandable valves) showed a significant association of self-expandable valves with lack of resolution of leaflet thrombosis (p=0.017). In multivariable logistic regression analysis, this association persisted (p=0.043) and was independent of the type of anticoagulation (p=0.660) and prosthesis diameter (p=0.942). Conclusion Persisting leaflet thrombosis despite anticoagulation is not infrequent and seems to be associated with prosthesis-type rather than small valve diameter or type of anticoagulation. Further research is necessary to identify structural aortic valve determinants for this finding. Funding Acknowledgement Type of funding source: None