Optimization of Device Deairing and Airless Connection Techniques for Cleveland Clinic Continuous-Flow Artificial Heart

Abstract

Prevention of air introduction during mechanical circulatory support device implant is critical for a successful outcome. A substantial amount of air may be introduced into the circulation during pump to outflow port connection, which may become detrimental for optimal pump function and long-term survival. In this study, we evaluated techniques of seamless, airless connection of double-ended centrifugal pump (continuous-flow total artificial heart [CFTAH]) in vivo. The airless CFTAH connection techniques were evaluated in acute in vivo (n=2) CFTAH implants (Jersey calves, weight: 77.8 and 80.8 kg). Techniques consisted of pump priming with normal saline (Fig. 1 A) and application of specifically designed connection sleeve (Fig 1B). The silicone sleeve (0.3-0.5 mm thick) was prototyped using multilayer dip-coating technique over a 3D-printed mandrel. A suture line was added along the long axis, to enable easy removal. Deairing sleeve was pre-placed on each outflow port (conduit) and proximal port (port) ends (Fig.1 C). The present air was evacuated upward from an open line. The conduit and pump ports were connected within the sleeve (Fig.1 D), with air being fully excluded from circuit. The CFTAH was started at the minimum speed (2,200 rpm) after connection. The CFTAH pump were successfully primed with saline prior to implant to remove entrapped air. The completely seamless pump connection and exclusion of air from pump and outflow grafts has been found feasible. There were no clinical signs of air embolism in the pulmonary or systemic circulation observed during the experiment. The seamless connection of CFTAH to outflow grafts using specifically designed connection sleeve and its easy removal was demonstrated to be feasible. Device development is ongoing and will aim to address optimal geometry, size and material selection.