Influence of Prolapse Volume in Mitral Valve Prolapse.

Mitral valve prolapse (MVP) is characterized by excessive leaflet tissue leading to a wide spectrum of mitral regurgitation (MR) ranging from trivial to severe. The prolapse volume (PV) below the prolapsing leaflets in end-systole was suspected to impact both chamber remodeling and MR grading in MVP. Based on 157 consecutive patients (45 women; mean age 62±15) referred for CMR assessment of MR, either from MVP (n = 91; 58%) or fibroelastic disease (FED) (n = 66; 42%), we sought to study (i) the interaction between PV and cardiac chamber geometry (ii) to study the impact of PV on MR quantification in MVP. Despite similar left ventricular (LV) size, PV was larger in MVP (11±9ml) than in FED (2±2ml). PV progressively increased with the severity of MR in MVP but not in FED. Despite a low regurgitant volume (32±18ml), some MVP patients with less than moderate MR exhibit significant cardiac chambers remodeling compared to 52 age and sex-matched controls. PV correlated significantly (r = 0.52) with the LV dilatation in severe MR but also in less than moderate MR. In MVP, PV>14ml was associated with a significant underestimation (Bias=-26±32ml) of regurgitant volume by PISA compared to CMR. In conclusion, in MVP, PV may play a role in left cardiac chambers remodeling, even in patients without severe MR, and in discordant grading of MR between echocardiography and CMR.