Sequential Platelet and Fibrinogen Turnover Studies Associated with left Ventricular Assist Device (LVAD) Implantation

Quantitation of thromboembolism is necessary to guide polymer fabrication and anticoagulant use for artificial organ implantation. Therefore as part of the LVAD program we have solid-phase radioiodinated bovine fibrinogen and developed an autologous ¹¹¹In technique to quantitate platelet survival. Mean platelet survival time(n/a) by the method of Murphy and Francis was 130±20 hrs for 10 animals; platelet aggregation and serotonin release were unaffected by the labelling procedure, n/a for homologous fibrinogen was 55.0±7.3 hrs. for 11 cows; clottability was 93%.

LVAD implantation of the Thoratec Model VIC devices with textured surfaces produced both shortened platelet (47+4.4 hrs.) and fibrinogen survival (30±4.6 hrs.) at 24 hrs. despite coumadin, aspirin and persantin. Survival curves changed from linear to curvilinear, suggesting consumption. Sequential studies at 1, 2 and 4 weeks showed continued platelet and fibrinogen consumption though to lesser degrees than at 24 hrs. Despite coumadin, aspirin and persantin, on-going consumption is occurring and can be quantitated, thereby providing a laboratory monitor to guide future development and clinical use of the LVAD.