Functional mitral regurgitation in chronic ischemic coronary artery disease: Analysis of geometric alterations of mitral apparatus with magnetic resonance imaging
|Issue Date:||31-Jul-2005||Publisher:||臺北市：國立臺灣大學醫學院外科||Start page/Pages:||543-551||Source:||The Journal of Thoracic and Cardiovascular Surgery 128(4)||Abstract:||
Background: Patients with chronic coronary artery disease have double the mortality
rate if the condition is combined with functional mitral regurgitation. An understanding
based on geometric alterations of the mitral apparatus in functional mitral
regurgitation is desirable.
Methods: Twenty-nine subjects were enrolled in the study, including 9 healthy volunteers
(control group), 12 patients with chronic coronary artery disease without functional
mitral regurgitation (CAD group), and 8 patients with chronic coronary artery disease
with functional mitral regurgitation (CADFMR group). Cine magnetic resonance
imaging was performed to acquire multiple short-axis cine images from base to apex.
Left ventricular end-systolic volume, left ventricular ejection fraction, mitral area, and
vertices of the mitral tetrahedron, defined by medial and lateral papillary muscle roots
and anterior and posterior mitral annulus, were determined from reconstructed images
at end-systole. Anterior-posterior annular distance, interpapillary distance, and annularpapillary
distance (the distance from the anterior or posterior mitral annulus to the
medial or lateral papillary muscle roots) were calculated.
Results: Left ventricular end-systolic volume was inversely associated with left
ventricular ejection fraction (R2 0.778). Left ventricular end-systolic volume was
highly associated with distances related to ventricular geometry (R2 0.742 for
interpapillary distance, 0.792 for the distance from the anterior mitral annulus to the
medial papillary muscle root, and 0.769 for distance from the anterior mitral annulus to
the lateral papillary muscle root) but was moderately associated with distances related
to annular geometry (R2 0.458 for anterior-posterior annular distance and 0.594 for
mitral area, respectively). Moreover, interpapillary distance of greater than 32 mm and
distance from the anterior mitral annulus to the medial papillary muscle root of greater
than 64 mm readily distinguished the CADFMR group from the other groups.
Conclusion: In patients with coronary artery disease, an increase in left ventricular
end-systolic volume is associated with inadequate approximation of the mitral tetrahedron
during systole, which consequently leads to functional mitral regurgitation. Our
study suggests that interpapillary distance and distance from the anterior mitral annulus
to the medial papillary muscle root are sensitive to the increase in left ventricular
end-systolic volume and reliably indicate the presence of functional mitral regurgitation.
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