Pseudonormalized mitral valve prolapse by secondary left ventricular remodeling

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K20721
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 90130:Medical systems-related
• Research Institution: University of Occupational and Environmental Health, Japan
• Principal Investigator: Iwataki Mai 産業医科大学, 医学部, 講師 (40771308)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 僧帽弁逸脱症 / 左室リモデリング / 僧帽弁閉鎖不全症 / 3次元経食道心エコー図法

Outline of Final Research Achievements

In patients with mitral valve prolapse (MVP) and severe mitral regurgitation (MR), nonprolapsed mitral valve leaflets are often apically tented due to secondary mitral valve tethering with left ventricular (LV) remodeling. This secondary mitral valve tethering may act on prolapsed leaflets as long as the leaflets have connection to papillary muscles. We, therefore, hypothesized that secondary LV remodeling is associated with attenuated mitral valve superior shift in patients with primary severe MR. Some patients with severe MR and MVP, 3D transesophageal echocardiography was performed. MVP volume relative to mitral valve annulus, MVP volume relative to opposing non-prolapsed leaflet, leaflet tip MV prolapse relative to non-prolapsed leaflet, 1) MV leaflet tip prolapse area was significantly correlated with MR VCA index. 2) MV leaflet tip prolapse area was positive correlated with LV mid-systolic volume (LVMSV). MV leaflet tip prolapse area is superior to evaluate severity of MVP.

Free Research Field

心エコー図学

Academic Significance and Societal Importance of the Research Achievements

重症MRでは、弁輪を基準としたMVP容量は、左室拡大により減少したが、非逸脱弁尖を基準としたMVP容量と逸脱弁尖先端のMVP面積は、左室拡大でも減少しなかった。さらに、弁尖先端MVP面積はMR重症度と有意相関を認めた(R=0.72, p<0.0001)。高度左室拡大を伴った重症MVP例(重症MRを伴う)は、弁輪を基準としたMVP容量は減少する一方で、弁尖先端MVP面積は重症となり、MR重症度に合致した。本研究により、MVPに伴う重症MRの決定因子や病態の理解が得られ、外科的弁形成術やMitraClip時の治療ターゲットが解明し、治療へ貢献すると考える。