Dynamic change in the left ventricular base with or without a rigid mitral valve prosthesis

Area of Science:

• Cardiovascular Imaging
• Biomedical Engineering
• Prosthetic Heart Valves

Background:

• Left ventricular outflow tract (LVOT) narrowing can occur with prosthetic mitral valves.
• Understanding the geometric relationship between mitral valve prostheses and the left ventricle is crucial for optimizing device performance.

Purpose of the Study:

• To evaluate the systolic narrowing of the left ventricular outflow tract (LVOT) caused by rigid mitral valve prostheses.
• To investigate the geometric relationship between the mitral valve annulus (MVA) and the left ventricular base (LVB) in patients with mechanical mitral prostheses.

Main Methods:

• Three-dimensional reconstruction of mitral valve annulus (MVA) and LVOT orifice from patient imaging.
• Projection of MVA and LVOT images onto the plane of the left ventricular base (LVB).
• Calculation of MVA-LVB ratio (Sm/Sb) during systole in patients and normal subjects.

Main Results:

• In normal subjects, the MVA-LVB ratio remained relatively constant during systole (59-62%).
• In patients with mechanical mitral prostheses, the MVA-LVB ratio significantly increased during systole (61% to 69%).
• An increased MVA-LVB ratio indicates a reduced proportionate share of the LVOT orifice relative to the total LVB.

Conclusions:

• Rigid mitral valve prostheses can lead to dynamic LVOT narrowing.
• Flexibility at the annulus is desirable for optimal performance of mitral valve prostheses.
• This geometric change impacts left ventricular dynamics and suggests design considerations for future prostheses.