Quantifying mitral regurgitation in MVP: the added value of three-dimensional continuity equation

Quantifying mitral regurgitation (MR) in patients with mitral valve prolapse (MVP) is particularly challenging due to the complex mitral valve anatomy, presence of multiple eccentric jets, and non-holosystolic regurgitation. The continuity equation (CE) offers a potentially more accurate method for assessing MR regurgitant volume in this population.

We evaluated patients with MVP and at least moderate MR. Regurgitant volumes (RVol) were quantified using the three-dimensional continuity equation (3D-CE) with direct area measurements and compared with RVol derived from the conventional diameter-based continuity equation (D-CE) and cardiovascular magnetic resonance (CMR). Among 72 patients (mean age 59.7 years, 65% female), bileaflet MVP was present in 86% and MAD in 96%. Multiple MR jets (32%) limited PISA accuracy (r = 0.40 with CMR). Compared with 3D-CE, D-CE overestimated RVol by 19 mL, though correlation remained strong (r = 0.74). In 21 paired studies, 3D-CE and CMR showed excellent agreement (r = 0.94, bias +2.1 mL). Severity grading showed strong concordance, with most discrepancies within one category.

In patients with MVP, incorporating 3D annular measurements into 3D-CE improves agreement with CMR-based volumetric assessment and mitigates overestimation associated with D-CE and PISA-based methods. This approach may be particularly valuable in patients with moderate or moderate-severe MR, in whom conventional echocardiographic parameters are frequently discordant, and supports the role of integrative multimodality imaging in refining MR severity assessment and guiding clinical management. Larger prospective studies are warranted to confirm these findings.