A Sheep Model for Thoracic Aortic Surgery in the Presence of Systemic Coagulopathy
Authors: Tran, H. S.; Chrzanowski, F. A.; Puc, M. M.; Marra, S. W.; Cilley, J. H.; Malli, D.; Patel, N.; Hewitt, C. W.; Delrossi, A. J.
Source: Journal of Investigative Surgery, Volume 13, Number 2, 1 March 2000 , pp. 111-116(6)
Publisher: Informa Healthcare
Abstract:Surgical repair of aneurysms, traumatic injuries, or congenital anomalies of the thoracic aorta are associated with high morbidity and mortality mainly as a result of excessive and uncontrollable hemorrhage from diffuse coagulopathy. We developed a model in sheep that simulates this coagulopathic state for experimentation with thoracic aorta surgery. This experimental animal model involves administering a 600-mg aspirin suppository once a day for the 2 days preceding surgery and a final dose on-call to surgery. Prior to cross-clamping the aorta, an intravenous (iv) bolus of heparin (400 IU/kg) was administered. Thirty minutes later, the iv heparin bolus was repeated. Pre and intraoperative activated clotting time was 101+-10 s and > 1500 s (p < .0001); prothrombin time, 21+-1 s and >100 s (p < .0001); and activated partial thromboplastin time, 20+-1 s and > 50 s (p < .0001), respectively. We utilized a partial cross-clamp-and-sew technique to anastomos a woven, gelatin-impregnated, 16-mm tube graft end-to-side to the descending thoracic aorta. Mean total blood loss was 1367+- 282 mL, which included mean blood loss from time of release of aortic cross-clamp to close (422+-135 mL) and mean total blood output from chest tube drain (945 203 mL). The mean time to achieve hemostasis at suture lines after aortic cross-clamp release was 15.5 6.6 min. In conclusion, a sheep model with induced coagulation defects was successfully developed and reproducible for experimentation involving thoracic aortic surgery.
Document Type: Research Article
Publication date: March 1, 2000