P299Patient-specific mitral valve model from 3D echocardiographic imaging: towards the virtual heart for surgery planning


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Abstract

Purpose: Finite element models (FEMs) represent an innovative approach for biomechanical analysis of cardiac structures. Our aim were to: 1) obtain a realistic FEM of the mitral valve (MV) by using mitral annulus (MA) and papillary muscles (PMs) patient-specific information from transthoracic (TTE) real-time 3D echocardiography (RT3DE), applying this strategy to 3 normals (NL) and 3 patients with organic MV prolapse (MVP); 2) test for differences in FEM quantitative parameters; 3) validate FEM morphology in MVP by comparison with transesophageal (TEE) RT3DE.Methods: RT3DE (Philips) was performed via TTE in all subjects, and also by intraoperatory TEE in MVP patients. The MA position was obtained frame-by-frame from TTE data, by custom 3D tracking, and integrated into patient-specific FEM, where time-dependent pressure up to 120 mmHg was applied on the leaflets to simulate closure. TEE data were separately analyzed (QLab, Philips) to obtain 3D MV reconstructions.Results: Compared to NL, in MVP leaflets maximum principal stresses showed asymmetric distribution at systolic peak, larger in anterior MA and decreasing towards the free margin, with the most stress focused in fibrous trigones. Both PMs tension and MA reaction forces at trigones increased by 50% in MVP, consistent with abnormal anchorage associated to MV insufficiency. FEM morphology captured with good approximation the position and extent of regurgitant areas, compared to TEE data (Figure).Conclusions: The adopted FEM strategy seemed flexible enough to reproduce different pathological scenarios and inter-subject variability, providing quantitative biomechanical parameters useful to interpret the effects of organic MV insufficiency. This approach represents the basis for the development of a patient-specific surgical planning tool.

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