Background: Recently, reports from multi-center data have been published showing subclinical leaflet thrombosis following bioprosthestic aortic valve replacement. We report the incidence and clinical presentation of leaflet thrombosis in patients referred for follow-up contrast enhanced CT angiography following TAVI.
Methods: 59 consecutive patients referred for follow-up CT angiography following TAVI were screened for inclusion in this analysis. In all patients, retrospectively ECG-gated spiral acquisition with tube modulation were performed to allow for assessment of leaflet motion. All prostheses were analyzed for presence of leaflet thrombosis defined as hypo-attenuated leaflet thickening with or without leaflet restriction. Post procedural antithrombotic regimen as well as symptom status was documented in all patients.
Results: 37 consecutive patients (21 males, 84±4 years) were analyzed. TAVI has been performed in all patients with either balloon-expandable prostheses or self-expandable prostheses. The interval between the index procedure and CT angiography was 2–8 months in 89% of the patients (in 4 patients after 10 days, 4 years, 12 and 20 months). Leaflet thrombosis was detected in 10 patients (27%, 7 Sapien 3, 2 Sapien XT, 1 SJM Portico, CT performed after 3–5 months in 8 patients and after 8 and 20 months in 2 patients). Out of 10 patients with CT-documented leaflet thrombosis, 9 patients had received post-procedural dual antiplatelet therapy for 3–6 months no patient was on effective oral anticoagulation at the time of CT examination. On the other hand, 11 out of 21 patients (52%) with no leaflet thrombosis were on continuous oral anticoagulation following TAVI. In patients with leaflet thrombosis, 3 leaflets were affected in 5 patients, 2 leaflets in 4 patients and in 1 patient only 1 leaflet was affected. Clinical symptoms (angina, dyspnea or both) were reported in 3/10 patients with leaflet thrombosis (40%) and in all 10 patients a significant increase of the mean echocardiographic gradient over the prosthesis was documented (mean: 7±2 mmHg directly after the index procedure versus 19±12 mmHg at the time of CT angiography, p=0.016). The percentage increase in mean gradient was significantly higher in symptomatic versus asymptomatic patients (83%±4 versus 34%±23, respectively, p=0.01) with improvement of symptoms following oral anticoagulation. Follow-up CT was available for 4 patients with complete resolution of the hypo-attenuated leaflet thickening following treatment.
Conclusion: Leaflet thrombosis following TAVI is a relatively frequent finding in patients referred for contrast enhanced CT angiography following TAVI and follows a subclinical course in the majority of patients. It is substantially more frequent in individuals who are not on oral anticoagulation. However, in patients with relevant increase in prosthetic gradients, symptomatic presentations are possible with improvement on oral anticoagulation.