The Role of Infarct Stiffness in Cardiac Patch Therapy: A Computational Study Using an Idealized Left Ventricular...

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Computational Biology

Background:

• Myocardial infarction (MI) leads to heart failure (HF) due to adverse ventricular remodeling.
• Tissue-engineered contractile patches are a potential therapy for restoring cardiac function.
• Infarct mechanical properties, such as stiffness and thickness, may impact patch efficacy.

Purpose of the Study:

• To computationally investigate how infarct tissue stiffness and wall thickness affect the functional restoration provided by a cardiac patch.
• To quantify the impact of infarct mechanical properties on cardiac mechanics and patch contribution.

Main Methods:

• A computational model of cardiac mechanics simulated MI in 15% of the left ventricle.
• Active stress generation was removed in the infarct region; passive stiffness and wall thickness were varied.
• A cardiac patch was modeled as healthy myocardium, with its volume 25% of the infarcted tissue.

Main Results:

• Following MI, stroke work decreased by 32%, with greater loss at higher infarct stiffness and lower wall thickness.
• The cardiac patch restored up to 15% of the lost stroke work.
• Patch contribution was one-third direct and two-thirds indirect (improved adjacent myocardium function).
• Decreased infarct stiffness improved overall pump function restoration and the patch's relative contribution.
• Reduced wall thickness improved pump function but decreased the patch's relative contribution.

Conclusions:

• Lower infarct stiffness, achieved through reduced tissue stiffness or wall thinning, enhances cardiac function restoration via patch implantation.
• The mechanical environment of the infarct significantly influences the success of cardiac patch therapy.