The balloon impasse sign in percutaneous transvenous mitral valvuloplasty

Percutaneous transvenous mitral valvuloplasty (PTMV) is an established therapy for rheumatic mitral stenosis (MS). While the Wilkins score standardizes the description of valve anatomy and predicts successful PTMV, echocardiographic assessment has some limitations. The ‘balloon impasse’ sign is the inability to cross a stenotic valve with a deflated Inoue balloon. This sign was described in the 1990s as an indicator of severe subvalvular thickening (regardless of the echocardiographic findings), portending an increased risk of severe mitral regurgitation (MR) post-PTMV. Despite its implications for management, it has been seldom reported. A 57-year-old woman with symptomatic, severe MS and a Wilkins score of 7 underwent PTMV. The ‘balloon impasse’ sign was observed when attempting to cross the stenotic valve. When the balloon was fully inflated, severe MR was noted, and the patient required mitral valve replacement. This case demonstrates the continued importance of the ‘balloon impasse’ sign and its implications for the therapeutic efficacy of PTMV.