Hemolysis after transcatheter mitral valve replacement in degenerated bioprostheses, annuloplasty rings, and mitral annular calcification: Incidence, patient characteristics, and clinical outcomes

Objectives: To determine the incidence, characteristics, and outcomes of patients with hemolysis after transcatheter mitral valve replacement (TMVR).

Background: Hemolysis is an increasingly recognized complication of TMVR. Clinical outcomes and optimal management for patients with hemolysis after TMVR are unclear.

Methods: Patients that underwent mitral valve-in-valve (MViV), valve-in-ring (MViR), and valve-in-mitral annular calcification (ViMAC) at a single center were retrospectively assessed.

Results: A total of 101 patients had TMVR, including 69 with MViV, 14 with MViR, and 18 with ViMAC. ViMAC patients had an increased frequency of mild or greater paravalvular leak (PVL) (ViMAC, 72.2%; MViR, 14.3%; MViV, 13.0%; p < .001). Hemolysis occurred in eight patients and was more common after ViMAC (ViMAC, 33.3%; MViR, 7.1%; MViV, 1.5%; p < .001). This required transfusion in five (ViMAC, 4; MViV, 1) and was associated with acute kidney injury in five with ViMAC. Among the ViMAC patients, four had transcatheter re-intervention to treat hemolysis with resolution of anemia in three and mild residual anemia in one with persistent mild PVL. The two ViMAC patients without re-intervention had persistent anemia and died within 6 months. Both MViV and MViR patients with hemolysis did not have PVL but had turbulent flow from left ventricular outflow tract narrowing and their hemolysis was self-limited.

Conclusions: Hemolysis occurs with greater frequency and increased clinical severity after ViMAC as compared to MViV or MViR and is likely related to increased incidence of PVL. These findings demonstrate the need to investigate novel strategies that can reduce the burden of hemolysis with ViMAC.