Material properties of CorCap passive cardiac support device

Area of Science:

• Biomedical Engineering
• Cardiovascular Mechanics
• Materials Science

Background:

• Congestive heart failure (HF) leads to myocardial dysfunction and ventricular remodeling.
• Ventricular restraint therapy with cardiac support devices (CSDs) aims to reduce ventricular stress and halt remodeling.
• The mechanical properties of CSDs, particularly their anisotropy, are not well understood.

Purpose of the Study:

• To investigate the mechanical properties of a specific CSD (CorCap) in different fiber orientations.
• To determine the stiffness of the CSD material along various axes relevant to cardiac implantation.

Main Methods:

• Composite specimens of CorCap fabric and silicone were created with varying fiber orientations.
• Biaxial testing was performed using a custom stretcher to assess stress-strain behavior.
• CSD coefficients and stiffness were calculated based on composite and silicone matrix data.

Main Results:

• Silicone matrix exhibited linear behavior with a stiffness of 2.57 MPa.
• CSD composites showed higher stiffness along the aligned fiber direction (14.39 MPa) compared to the cross-fiber direction (5.66 MPa).
• When oriented for clinical use, the CorCap demonstrated greater stiffness circumferentially (10.55 MPa) than longitudinally (9.70 MPa).

Conclusions:

• The CorCap exhibits significant mechanical anisotropy, with greater stiffness in the circumferential direction.
• Understanding and accounting for this directional biomechanical property is essential for optimizing the clinical application of the CorCap for ventricular restraint.