Antibiotic-associated eosinophilic and occlusive arteritis in calves complicating preclinical studies of left ventricular assist devices

In vivo Hemodynamic Evaluation of an Implantable Left Ventricular Assist Device in a Long-term Anti-coagulation Regimen

Left ventricular assist devices (LVADs) are used to treat patients with severe (New York Heart Association class IV) heart failure. Thrombosis and bleeding are severe LVAD-related complications; thus, an effective anticoagulation regimen is crucial for successful postoperative management. The CH-VAD™ (CH Biomedical, Inc.) is a small, implantable, full-support (>5 L/min) LVAD with a centrifugal flow pump that has a fully magnetically levitated rotor, which confers superior hemocompatibility. In this study, the CH-VAD™ was implanted in two calves to evaluate its hemocompatibility and to establish an anticoagulation regimen for future GLP (good laboratory practice) studies. Heparin infusion was used during the surgery, and during postoperative management, the proper dosage of warfarin was given orally to maintain an international normalized ratio (INR) between 2.0 and 3.0. Pump performance, animal condition, and hematology results were recorded throughout the study (approximately 60 days). The results show that under the established anticoagulation regimen, the CH-VAD™ was well tolerated in the bovine model, with no significant thrombus or thromboembolic lesion formation in distal end organs. Low plasma free hemoglobin levels suggest that the device did not cause hemolysis. These results and the experience gained pave the way for future GLP studies.

In Vivo Hemodynamic Evaluation of CH-VAD in a Bovine Model for 14 Days

The CH-VAD is a centrifugal-flow magnetically levitated (maglev) left ventricular assist device (LVAD) used to treat end-stage heart failure. It is implanted in the chest cavity; the inflow cannula is inserted into the apex of the left ventricle, and the outflow graft is anastomosed to the aorta. Among several key VAD system improvements, the CH-VAD has a smaller body size than other LVADs and its maglev system offers a large-gap design that makes it superior in terms of hemocompatibility. In this study, we implanted the CH-VAD in a calf and evaluated the hemodynamic and hemocompatibility characteristics over a 14-day period. The hemodynamic parameters, the pump data, and blood test results were recorded throughout the study. The results showed that the CH-VAD provided hemodynamic stability. Hemocompatibility testing indicated negligible hemolysis throughout the study, and no signs of infection were seen. On necropsy, the results showed only expected focal mild-to-moderate adhesions between the pericardial sac (along the pump) and the adjacent rib cage, and between the pericardial sac and the heart. Gross examination of internal organs was unremarkable. Examination of the CH-VAD after explantation revealed no evidence of thrombus formation internally or around the inflow or outflow cannulas.