Cutting second-order chords does not prevent acute ischemic mitral regurgitation.

Area of Science:

• Cardiovascular Surgery
• Cardiac Mechanics
• Mitral Valve Disease

Background:

• Ischemic mitral regurgitation (IMR) is a common complication of myocardial infarction.
• Chordal cutting has been proposed as a surgical technique to address IMR.
• The efficacy of cutting anterior mitral leaflet second-order chordae in preventing acute IMR requires further investigation.

Purpose of the Study:

• To evaluate the effectiveness of cutting anterior mitral leaflet second-order chordae in preventing acute ischemic mitral regurgitation (IMR).
• To assess the impact of this chordal cutting on left ventricular (LV) systolic function and mitral valve geometry during acute ischemia.

Main Methods:

• Six sheep underwent radiopaque marker placement for 3D coordinate acquisition.
• Second-order chordae were identified and encircled with wire snares.
• Biplane videofluoroscopy and Color Doppler transesophageal echocardiography were used to assess mitral regurgitation (MR) and LV function before and during acute ischemia, both before and after chordal cutting.

Main Results:

• Chordal cutting increased anterior leaflet inflection angle but did not alter effective leaflet length.
• Left ventricular systolic function, assessed by PRSW, decreased significantly after chordal cutting.
• Acute ischemia induced annular dilation, posterior papillary muscle displacement, and increased leaflet tenting area and volume, irrespective of chordal cutting.
• Mitral regurgitation increased significantly during ischemia, and this increase was not attenuated by second-order chordae cutting.

Conclusions:

• Cutting anterior mitral leaflet second-order chordae did not prevent or reduce the severity of acute IMR.
• The procedure resulted in impaired left ventricular systolic function.
• Chordal cutting did not mitigate ischemia-induced annular dilation, leaflet tenting area, or leaflet tenting volume.