Author + information
- Jesse Baucom1,
- Alex Hill2,
- Rajiv Gupta3,
- Srinivasan Varahoor4,
- John Karanian1 and
- William Pritchard1
- 1FDA Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Laboratory of Cardiovascular and Interventional Therapeutics, Laurel, MD
- 2Medtronic Cardiovascular, Mounds View, MN
- 3Massachusetts General Hospital, Harvard Medical School, Boston, MA
- 4Medtronic Cardiovascular, Minneapolis, MN
Novel transcatheter mitral valve replacement devices are currently undergoing development for treatment of mitral valve disease. Although animal models are used to study safety and effectiveness of these devices, interspecies differences in the geometry and motion of the mitral valve orifice are not well characterized in the literature. The purpose of this study was to develop a quantitative characterization of geometry and motion of the mitral valve orifice over the cardiac cycle in animal models compared to human.
Gated cardiac CT angiograms over the cardiac cycle in eight swine, sheep and normal adults were analyzed (Mimics, Materialise, Leuven, Belgium). Measurements were taken at late diastole and mid-systole, corresponding to maximum and minimum mitral annular areas, respectively. Using a novel mathematical approach to define a two-dimensional outline of the mitral annulus, area, perimeter, and axial lengths were calculated (MATLAB). Area, perimeter, and ellipticity were measured for a left atrial plane 1.0 cm into the left atrium and parallel to the mitral annular plane.
Mitral annular area and perimeter increased in late diastole compared to mid-systole in all three species (Table 1). Area was smaller in swine than in humans in both phases and perimeter was smaller in swine in late diastole. Area of the left atrial plane increased in swine in late diastole but decreased in sheep and humans. Area and perimeter of the atrium in this plane was larger in swine comparted to humans in late diastole.
Mitral annular area and perimeter in sheep were not different from humans, while there were differences between swine and humans. Left atrial area increased in swine in late diastole but decreased in both sheep and humans. These data should inform the design and evaluation of mitral valve replacement technology.