Left ventricular function after surgical correction of chronic mitral regurgitation

Area of Science:

• Cardiology
• Cardiovascular Surgery
• Biomedical Engineering

Background:

• Mitral regurgitation (MR) is thought to increase left ventricular ejection fraction (EF) by reducing systolic load.
• Mitral valve replacement (MVR) is believed to increase afterload, causing a postoperative EF decrease.
• These assumptions lack direct clinical confirmation in chronic MR patients.

Purpose of the Study:

• To investigate the actual systolic wall stress and stress-shortening relations in patients with chronic MR.
• To determine the factors influencing left ventricular function post-MVR in compensated and decompensated MR.

Main Methods:

• Evaluation of systolic wall stress before and after MVR.
• Assessment of stress-shortening relations in compensated and decompensated chronic MR patients.

Main Results:

• Chronic MR patients exhibit normal or high systolic wall stress, refuting the unloading hypothesis.
• Decompensated MR patients show increased systolic wall stress post-MVR, potentially lowering EF.
• Compensated MR patients experience reduced wall stress post-MVR, yet EF still declines, suggesting other factors.

Conclusions:

• Chronic MR does not cause systolic unloading.
• Post-MVR EF decline in decompensated MR may relate to increased afterload.
• In compensated MR, reduced EF post-MVR is likely due to prosthetic valve complications, not increased afterload.