Cardiac Patch Delivery Device
Cardiac Patch Delivery Device
Cardiac Patch Delivery Device
For my senior capstone course, Medical Device Design (2.75), my team and I spent the semester developing and designing a cardiac patch delivery device which can deliver multiple types of cardiac patches to the heart in a minimally invasive and controlled manner. Heart failure is a major issue and the leading cause of death in America. When someone has a heart attack, or myocardial infarction, tissue in the heart muscle dies due to a lack of blood flow through the heart’s arteries. Various types of cardiac patches have been developed to mechanically reinforce the dead tissue, or infarct, after the heart attack. Early intervention is crucial in reinforcing the infarct, so these patches are most effective if deployed immediately after the cardiac event. However, the delivery of these patches is currently really invasive and requires open heart surgery. Such an aggressive procedure is unsafe immediately after a myocardial infarction, so the patches are currently not being used. Therefore, there is a clinical need for a device that can enable minimally invasive patch delivery to allow more patients to benefit from cardiac reinforcement as a therapeutic measure after a heart attack. Our device addresses this need in an innovative and cost-effective manner.
Cardiac patches are one promising mode of mechanical reinforcement that are not yet clinically practical due to the invasiveness of implantation. We developed a minimally invasive patch delivery device. This device was designed to (1) fit a patch that is up to 50 mm in maximum planar dimension into a 12 mm trocar, (2) deploy multiple sizes and shapes of patches, (3) unroll the patch and adhere it to heart tissue without large creases, (4) prevent self-adhesion of patch during deployment, and (5) control the timing and orientation of patch release. The device consists of shape-set Nitinol wires which slide into pockets on either edge of the patch. The patch can subsequently be rolled up around the wires in a scroll-like manner to fit into a retractable sheath, which all fits inside a trocar. Once the tool is inserted into the pericardium through a subxiphoid approach after an apical pericardial incision, the sheath is retracted and a 3D printed wedge pushes the wires apart to unroll the patch. A PVA backing which dissolves when hydrated prevents the patch from adhering to itself. When the patch is held on the epicardial surface with the conformable tool, the PVA backing is hydrated and begins to dissolve, allowing the patch to adhere to the epicardium. The function of the device was tested on an ​ex vivo porcine heart with beating motion simulated by a cyclically inflated intraventricular balloon. These tests confirmed successful expansion and retraction of the patch delivery device and demonstrated the ability to apply adhesive patches to the epicardial surface of a beating heart.
Depiction of Subxiphoid Approach
Below is a final presentation about the device as well as an academic paper documenting the design and testing methods and results.
The paper below was submitted and accepted to the 2021 Design of Medical Devices Conference at the University of Minnesota where our team presented our work.