Mitral Valve Insufficiency in the Context of Barlow's Disease: A Contemporary Review of Etiopathogenesis, Multimodal Assessment, and Evolving Management Paradigms

Barlow's disease represents a distinct and complex morphological variant of degenerative mitral valve disease, characterized by a unique pathophysiological substrate leading to severe mitral insufficiency. This extensive review provides a comprehensive synthesis of contemporary understanding, emphasizing the transition from a purely anatomical curiosity to a clinically nuanced entity with significant implications for management. The etiopathogenesis is explored through the lens of advanced histopathological and molecular studies, highlighting the interplay between myxomatous degeneration, abnormal collagen metabolism, and genetic predispositions beyond the classic FBN1 and FLNA associations. A critical appraisal of current multimodal imaging is undertaken, detailing the pivotal role of high-resolution three-dimensional echocardiography in delineating the hallmark bileaflet prolapse with multisegment involvement, excessive leaflet tissue, and annular disjunction. Cardiac magnetic resonance and computed tomography are discussed for their growing utility in quantifying regurgitation volume, assessing ventricular remodeling, and informing surgical planning. The core of this review contrasts traditional surgical approaches, predominantly involving complex valve repair with extensive leaflet resection and annuloplasty, against emerging reparative techniques and the evolving, albeit controversial, potential of transcatheter edge-to-edge repair in select, high-risk cohorts with suitable anatomy. Long-term outcome data and persistent challenges, including repair durability, arrhythmic risk, and the management of asymptomatic severe regurgitation, are examined. This synthesis concludes by identifying critical knowledge gaps and future directions, particularly the need for refined risk stratification models integrating quantitative imaging biomarkers and genetics, and the call for dedicated randomized trials to guide therapeutic escalation in this heterogeneous patient population.