Transcatheter mitral valve implantation (TMVI) is now indicated to treat patients with bioprosthesis failure (valve-in-valve [ViV]), annuloplasty failure (valve-in-ring [ViR]) and severe mitral annulus calcification (ViMAC); however, few studies have investigated transcatheter heart valve (THV) thrombosis.
As part of the Young Investigator Award Session on Thrombosis held today, Doctor John Kikoïne (Hospital Bichat-Claude Bernard, Paris, France) presented data on the incidence of THV thrombosis and outcomes in patients undergoing TMVI.
The investigators studied all 130 consecutive patients undergoing TMVI at Hospital Bichat-Claude Bernard between July 2010 and September 2019 (62 ViV, 34 ViR and 34 ViMAC). Transoesophageal echocardiography (TOE) and computed tomography (CT) were performed at discharge, 3 months, 1-year and yearly thereafter. THV thrombosis was defined as the presence of at least one thickened leaflet with restricted motion suggestive of thrombus confirmed by TOE or contrast CT. THV thrombosis was classified according to the timing of diagnosis as immediate (until discharge), early (after discharge, until 3 months) or late (beyond 3 months). All patients received anticoagulation therapy with vitamin K antagonists and a low dose of aspirin for the first 3 months.
THV thrombosis was observed in 16 (12.3%) patients, with a median time to diagnosis of 78 days. It was immediate in 43.7% of cases, early in 37.5% and late in 18.8%. Most of these thromboses were subclinical (93.7%) and non-obstructive (87.5%). No stroke or thromboembolic event occurred. After optimisation of antithrombotic treatment, THV thromboses resolved in all but one asymptomatic patient. Predictors were shock for immediate (p<0.001), male sex for early (p=0.045) and absence of anticoagulation for both early (p=0.018) and late (p=0.023) THV thromboses.
Thus, it appears that THV thrombosis occurs relatively frequently after TMVI, particularly in the first 3 months, but most cases are subclinical. THV thrombosis resolved after optimisation of anticoagulation suggesting that anticoagulation for at least 3 months may be necessary after TMVI.