AbstractObjectiveTo understand the clinical and hemodynamic response of patients with stenotic versus regurgitant prosthetic mitral valve degeneration to transseptal transcatheter mitral valve‐in‐ring/‐valve replacement (TMVR).BackgroundPatients with prosthetic mitral valve repair/replacement failure frequently present high‐risk surgical challenges. TMVR has been employed as an alternative to surgery.MethodsForty‐four patients with stenotic/regurgitant degeneration of prior prosthetic mitral annuloplasty and replacement (38) underwent mitral TMVR. Clinical, echocardiographic, and invasive hemodynamic monitoring was conducted at baseline and follow‐up.ResultsRelative to patients with regurgitant degeneration (28), patients with stenotic degeneration had baseline higher mitral valve gradients (12 ± 4 vs. 7 ± 3 mmHg, p < 0.01) and smaller areas (1.0 ± 0.4 vs. 1.5 ± 0.4 cm2, p = 0.01). TMVR yielded significant reduction in left atrial v‐wave pressures in stenotic and regurgitant cohorts (−7 ± 11, p = 0.03, and −11 ± 12 mmHg, p < 0.01, respectively) and significant, sustained symptomatic improvement. Intracardiac pressures overall, including left ventricular end diastolic pressures, remained elevated.ConclusionDespite baseline differences in valvular disease, TMVR leads to significant hemodynamic and clinical improvement in both stenotic and regurgitant prosthetic mitral valve disease. In both cohorts, TMVR reduced intracardiac pressures to similar postprocedural levels, but pressures remained supranormal. This outcome suggests a multifactorial process defines the pathophysiology of patients undergoing TMVR, including contributions from prosthetic degeneration, changes in left atrial compliance, and diastolic dysfunction, and highlights the need to consider such factors in patient evaluation and treatment.