Sunshine Heart Designs Innovative Heart Assist Device

The Challenge

Auckland Heart Surgeon & Scientist, Dr William Peters, was developing an implantable device, intended for use in patients in severe heart failure and in whom a transplant is not suitable or available. The device needed to have a fatigue life of at least 50 million cycles per year, for 5 years, but early prototypes (not installed in humans!) were failing far short of the design goal, achieving only 8 million cycles maximum

The Solution

Dr Peters turned to Matrix with the design of an inflatable membrane. The analysis simulation was particularly difficult and involved non-linear features such as hyper-elastic material, aortic tissue material, membrane fabric, large displacement and strain, surface-to-surface contact, etc. The simulation cycle involved inflating the curved aorta and then moving the aorta into contact with the balloon membrane, wrapping a fabric around the aorta to hold the balloon membrane against the aorta, and finally inflating the membrane to squeeze the aorta. Coupled with this were all the other issues associated with determining the fatigue life of an elastomer in a hostile environment.

The first phase of the project was completed with design recommendations made to the Sunshine Heart Company to minimise strains in both the balloon and the aortic wall. The next phase (the most critical) was building of the balloons.

The balloons underwent functionality and design life testing on a mock in vivo test rig and, after the equivalent of one year’s cycling, proved no failures. Similar results were seen in preclinical testing.

The Result

Dr Williams said "The Matrix team worked quickly with us to understand our requirements and specifications, then assembled these into practical design solutions, and provided us with real confidence in knowing how the balloon would perform in the human body - the results to date speak for themselves".