Does Preliminary Chest Shape Assessment Improve the Prognostic Risk Stratification of Symptomatic Individuals with Primary Mitral Regurgitation? A Narrative Review of Traditional and Innovative Prognostic Indicators

Primary mitral regurgitation (PMR) is the most common mitral valve disorder in clinical practice. Although several prognostic indicators derived from resting transthoracic echocardiography (TTE) and exercise stress echocardiography (ESE) are available, patient out-comes remain highly variable, with substantial differences in the risk of complications and mortality. Identifying individuals at lower cardiovascular risk is therefore clinically relevant, as they represent a large proportion of cases. Current guidelines recommend an integrative approach—combining qualitative, semiquantitative, and quantitative indices—to determine the timing of intervention, but they do not specifically address risk stratification of low-risk PMR populations. Recent studies from our group have demonstrated the prognostic importance of chest wall configuration, assessed noninvasively us-ing the modified Haller index (MHI). Defined as the ratio of latero-lateral thoracic diame-ter to the antero-posterior (A-P) sternum–spine distance, MHI has been shown to signifi-cantly affect myocardial deformation indices obtained by speckle tracking echocardiography (STE). Patients with PMR due to mitral valve prolapse (MVP) often present with reduced A-P thoracic diameter caused by sternal depression. Among these, individuals with MHI >2.5 or A–P diameter ≤13.5 cm displayed greater impairment in global and basal myocardial strain, particularly in longitudinal and circumferential directions. These ab-normalities appear to reflect extrinsic compressive forces and cardiac displacement lead-ing to intraventricular dyssynchrony, rather than intrinsic myocardial dysfunction. A reduced A-P diameter (≤13.5 cm) was also independently associated with mitral annular disjunction (MAD) in MVP and emerged as a key determinant of impaired strain in this subgroup. In a retrospective cohort of 424 symptomatic MVP patients with moderate MR undergoing ESE, positive tests and exercise-induced severe MR were uncommon (9.8% and 13.2%). Importantly, multivariable analysis revealed that MHI >2.5 or A–P diameter ≤13.5 cm was strongly linked to favorable medium-term prognosis, with very few adverse cardiovascular events. These findings suggest that chest wall assessment using MHI may help distinguish compression-related symptoms from hemodynamically significant MR and identify symptomatic PMR patients with a benign prognosis. This narrative review summarizes the evidence regarding conventional and novel echocardiographic prognostic markers and their implications for risk stratification in PMR.