Dynamic balance of the aortomitral junction.
OBJECTIVE
The aortic and mitral valves have been studied in isolation, as if their functions were independent. We hypothesized that both valves work in synchrony on the basis of the shared myocardial pump and orifice.


METHODS
Six sonometric crystals (7 sheep) were placed in both trigones, the midpoint of the anterior and posterior anulus, and the lateral extremities of the posterior anulus. In a separate series of animals, 3 crystals (8 sheep) were implanted in the aortic annular base of the right, left, and noncoronary sinuses of Valsalva. In an acute, open-chest model, under stable hemodynamic conditions, geometric changes were time related to simultaneous left ventricular and aortic pressures.


RESULTS
From mid-diastole to end-systole, the mitral anulus area contracted by -16.1% +/- 1.9% (mean +/- SEM), whereas the aortic base area expanded by +29.8% +/- 3.3% during systole. The mitral anulus deformation was heterogeneous. In systole, the anterior mitral anulus expanded (intertrigonal distance, +11.5% +/- 2.3%) and the posterior mitral anulus contracted (distance between lateral extremities of the posterior anulus, -12.1% +/- 1.5%). The intertrigonal distance corresponded to the base of the left and noncoronary sinus of Valsalva, which expanded similarly during systole (+12.9% +/- 2.0%). The anteroposterior diameter of the mitral anulus was reduced twice that of the transverse diameter. This disparity of reduction can be explained by the posterior displacement of the intertrigonal area corresponding to the systolic aortic root expansion.


CONCLUSIONS
Mitral anulus deformation is closely related to aortic root dynamics. During systole, the posterior movement of the aortic curtain allows for aortic root expansion, probably to maximize ejection, whereas during diastole, aortic root reduction participates in mitral anulus dilatation. These findings should affect mitral and aortic surgical approaches.
Lansac
Emmanuel
E
International Heart Institute of Montana Foundation at St Patrick Hospital, Missoula, Montana 59802, USA.
Lim
Khee Hiang
KH
Shomura
Yu
Y
Goetz
Wolfgang A
WA
Lim
Hou Sen
HS
Rice
Nolan T
NT
Saber
Hashim
H
Duran
Carlos M G
CM
D000818:Animals; D001021:Aortic Valve / Q000502:physiology* / Q000601:surgery*; D002318:Cardiovascular Diseases / Q000503:physiopathology / Q000601:surgery*; D003971:Diastole / Q000502:physiology; D004195:Disease Models, Animal; D006334:Heart Function Tests; D006439:Hemodynamics / Q000502:physiology; D008943:Mitral Valve / Q000502:physiology* / Q000601:surgery*; D012680:Sensitivity and Specificity; D012756:Sheep; D013599:Systole / Q000502:physiology