Reducing driveline infection risk in durable mechanical circulatory support devices with ultra-flexible wires for energy transfer.

Background: Driveline infections (DLIs) pose a burden to heart failure patients supported by durable mechanical circulatory support devices (dMCSs). A major factor to DLI comes from the low mechanical compliance of drivelines, affecting wound healing. New drivelines that mitigate mechanical stress on skin may reduce the risk of DLI. We investigate macroscopic and microscopic effects of wires with low flexural stiffness on the risk of DLI.

Methods: Prototypes equipped with ultra-flexible wires, due to their stranded metallic core and small diameter, were percutaneously implanted in an adult ovine model of DLI and subjected to electric conditions typical of dMCS operation. In the control (no bacterial inoculation, n=2 animals, follow-up period around 2 months) and inoculation (with Staphylococcus epidermidis, n=2 animals, follow-up period 1.5 months) study groups, the commercial dMCS drivelines and the prototypes were implanted at equivalent surgical sites of each animal. In the inoculation group, the surgical sites were infected with Staphylococcus epidermidis 2 weeks post-implantation.

Results: Ultra-flexible wires showed flawless electromechanical performance, enabled fast recovery of skin redness in the first 2 weeks (p<0.05), and reduced inflammation (p<0.0001) at the exit site compared to commercial dMCS drivelines. After S. epidermidis inoculation at the exit site, ultra-flexible wires displayed reduced bacterial number (34 times lower) compared to commercial dMCS drivelines, avoiding internal biofilm formation and macroscopic signs of infection.

Conclusions: Using small, ultra-flexible wires reduced wound size and mechanical stress at the exit site, strengthening barrier function and lowering the risk of DLI. The use of ultra-flexible wires may improve the quality and duration of life of patients supported with dMCS.