Functional mitral regurgitation in chronic ischemic coronary artery disease: Analysis of geometric alterations of mitral apparatus with magnetic resonance imaging☆
Received 13 December 2003; received in revised form 31 March 2004; accepted 6 April 2004.
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 (CAD+FMR 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 annular-papillary 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 CAD+FMR 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.
aDepartment of Surgery, National Taiwan University Hospital, Taipei, Taiwan, ROC
bDepartment of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan, ROC
cInstitute of Biomedical Engineering, National Taiwan University Medical College, Taipei, Taiwan, ROC
dCenter for Optoelectronic Biomedicine, National Taiwan University Medical College, Taipei, Taiwan, Republic of China
Address for reprints: Wen-Yih Isaac Tseng, MD, PhD, No. 1, Jen-Ai Road, Sec. 1, Center for Optoelectronic Biomedicine, National Taiwan University Medical College, Taipei, Taiwan, ROC
☆ This work was supported by the National Science Council, Taiwan (NSC91-2314-B-002-217-M08 and NSC93WFA0100159).
ABSTRACT