Abnormal mitral-aortic intervalvular coupling in mitral valve diseases: a study using real-time three-dimensional transesophageal echocardiography.

BACKGROUND: Mitral and aortic valves are coupled via fibrous tissue. This coupling is considered to be important for cardiac function before and after mitral valve surgery. The relationship between mitral-aortic coupling and different types of mitral regurgitation (MR) is not completely understood.

METHODS AND RESULTS: Real-time three-dimensional transesophageal echocardiography (RT3D-TEE) was performed in 133 subjects: 30 normal subjects, 15 patients with Carpentier type I MR (annular dilatation and congenital cleft), 40 type II (mitral valve prolapse), 20 type IIIa (rheumatic) and 28 type IIIb (ischemic mitral regurgitation). Custom software was used to track mitral (MA) and aortic annuli (AoA) in 3D space throughout cardiac cycle, allowing measurement of changes in mitral and aortic valve morphology. Normal mitral-aortic coupling is characterized by reciprocal changes in the annular areas throughout cardiac cycle, with systolic reduction of the angle between the two annular planes. In Carpentier type II patients, not only MA but also AoA areas were increased (P < 0.05 vs normal), but the reciprocal pattern of mitral-aortic coupling was preserved. In both type I IMR and IIIb patients, MA and AoA areas were both increased (P < 0.05 vs normal) and the reciprocal behavior of mitral-aortic coupling was lost. Only MA area was increased in type IIIa patients. The extent of mitral-aortic angle reduction during systole was diminished in all 4 Carpentier groups (P < 0.05 vs normal).

CONCLUSIONS: Mitral valve diseases may affect normal mitral-aortic coupling and aortic valve function. Different patterns of abnormal mitral-aortic coupling are associated with different Carpentier types of MR.