Differences in mitral valve-left ventricle dimensions between a beating heart and during saline injection test

Area of Science:

• Cardiovascular Surgery
• Cardiac Anatomy
• Surgical Echocardiography

Background:

• The saline injection test is commonly used during mitral valvuloplasty to assess regurgitation.
• Discrepancies exist between intraoperative saline test findings and postoperative echocardiography.
• Geometric differences in the mitral valve-left ventricular complex may explain these discrepancies.

Purpose of the Study:

• To compare the three-dimensional geometries of the mitral valve-left ventricular complex during a saline injection test versus a beating heart.
• To elucidate the geometric alterations that occur during the saline injection test.

Main Methods:

• Sonomicrometry crystal markers were implanted in seven mongrel dogs.
• Markers were placed at the mitral annulus, leaflet edges, papillary muscle tips, and left ventricular apex.
• Geometric data were acquired during both the saline injection test and in the beating heart state.

Main Results:

• The mitral annulus flattened, with increased commissural width and decreased annular height during the saline test.
• Mitral leaflet scallops were wider, and papillary muscle tips were further apart, indicating leaflet stretching.
• The distance between papillary tips and the annular plane remained constant.

Conclusions:

• The saline injection test can inform chordal reconstruction length.
• However, the test may yield inaccurate mitral-left ventricular dimensional data due to annulus flattening and leaflet overstretching.
• These geometric changes highlight potential limitations of the saline injection test for accurate regurgitation assessment.