Lumbar muscle atrophy caused by harness replacement in a chronic calf model of total artificial heart implantation.

The postoperative care of animals implanted with mechanical circulatory support devices is complex. The standard of care requires continuous monitoring of hemodynamic parameters post implant, wound care, and maintenance of the animal's well-being, but also includes controlling the animal's biomechanics under conditions of continuous restraint and harnessing. In such studies, a harness provides secure fixation of the exteriorized device driveline and pressure lines and aids animal handling (lifting, position adjustment, and assistance with standing up). Harnessing is a key element in large-animal surgery. It affects the animal's conditions, safety, and post-procedure troubleshooting and thus may drastically worsen postoperative outcomes if improperly handled. Here we report a case associated with an unplanned harness replacement in a chronic animal model implanted with the Cleveland Clinic continuous-flow total artificial heart. Inadvertent changes to the harness resulted in posture change caused by muscular atrophy of the calf's spine that had been under long-term harness support.