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Dynamic balance of the aortomitral junction
Emmanuel Lansac1, Khee Hiang Lim, Yu Shomura
1International Heart Institute of Montana Foundation at St Patrick Hospital, Missoula, Montana 59802, USA.
The Journal of Thoracic and Cardiovascular Surgery
|May 23, 2002
Summary
The mitral and aortic valves function synchronously, not independently. Aortic root expansion during systole drives mitral annulus deformation, impacting surgical strategies for both valves.
Area of Science:
- Cardiovascular Physiology
- Cardiac Mechanics
- Valvular Dynamics
Background:
- The aortic and mitral valves have historically been studied in isolation.
- Their functional independence has been a prevailing assumption in cardiovascular research.
Purpose of the Study:
- To investigate the synchronous function of the aortic and mitral valves.
- To test the hypothesis that these valves operate in synchrony due to the shared myocardial pump and orifice.
Main Methods:
- Sonometric crystals were implanted in sheep to measure geometric changes in the mitral annulus and aortic annular base.
- Simultaneous left ventricular and aortic pressures were recorded in an acute, open-chest model.
Main Results:
- The mitral annulus area contracted by -16.1% during systole, while the aortic base area expanded by +29.8%.
- Mitral annulus deformation was heterogeneous, with anterior expansion and posterior contraction.
- Aortic root expansion during systole was linked to posterior displacement of the intertrigonal area.
Conclusions:
- Mitral annulus deformation is intricately linked to aortic root dynamics.
- Systolic aortic root expansion and posterior movement facilitate maximal ejection.
- Diastolic aortic root reduction contributes to mitral annulus dilatation, suggesting implications for surgical approaches.