Chordal cutting: a new therapeutic approach for ischemic mitral regurgitation

Area of Science:

• Cardiovascular Surgery
• Cardiac Mechanics
• Interventional Cardiology

Background:

• Ischemic mitral regurgitation (MR) is linked to adverse prognosis in heart disease.
• Leaflet tethering due to papillary muscle displacement causes MR, which is not fully addressed by annular reduction.
• The hypothesis tested was that selective chordae cutting could reduce MR by releasing leaflet restriction.

Purpose of the Study:

• To investigate the efficacy of cutting specific basal chordae in reducing ischemic mitral regurgitation.
• To assess the impact of chordal cutting on mitral valve geometry and function.
• To explore a potential minimally invasive treatment for ischemic MR.

Main Methods:

• Experiments were conducted on 8 mitral valves, including a porcine in vitro model and 7 sheep with induced myocardial infarction.
• Three-dimensional (3D) echocardiography was used to quantify MR and analyze 3D valve geometry in vivo.
• Selective cutting of basal chordae was performed to release leaflet tethering.

Main Results:

• Papillary muscle displacement caused leaflet restriction and mild-to-moderate MR in all tested valves.
• Cutting the two central basal chordae effectively reduced MR without inducing prolapse.
• In vivo, MR significantly decreased from 7.1±0.5 mL/beat post-infarction to 0.9±0.1 mL/beat after chordal cutting (P<0.0001).

Conclusions:

• A minimal chordae cutting strategy can improve mitral valve coaptation and reduce ischemic MR.
• This approach offers a potential method for future minimally invasive interventions for ischemic MR.