Preliminary Study of the Effects of Smectite Granules (WoundStat) on Vascular Repair and Wound Healing in a Swine Survival Model

Abstract

WoundStat (WS) (TraumaCure, Bethesda, MD) is a topical hemostatic agent that effectively stops severe hemorrhage in animal models. To the best of our knowledge, no survival study has been conducted to ensure long-term product safety. We evaluated vascular patency and tissue responses to WS in a swine femoral artery injury model with survival up to 5 weeks. Anesthetized swine received a standardized femoral artery injury with free hemorrhage for 45 seconds followed by WS application. One hour after application, the WS was removed, the wound copiously irrigated, and the artery repaired using a vein patch. Six groups of three animals received WS and were killed either immediately after surgery or at weekly intervals up to 5 weeks. Three control animals were treated with gauze packing and direct pressure followed by identical vascular repair and survival for 1 week. At the time of killing, angiograms were performed, and tissue was collected for histopathology. Hemostasis was complete in all WS animals. All animals survived the procedure, and there were no clinically evident postoperative complications. Vascular repairs were angiographically patent in 15 of 18 animals (83%) receiving WS. Histopathologic examination of WS animals revealed severe diffuse fibrogranulomatous inflammation, early endothelial degeneration with subsequent intimal hyperplasia, moderate myocyte necrosis, and fibrogranulomatous nerve entrapment with axonal degeneration. Although an effective hemostatic agent, WS use was associated with a substantial local inflammatory response and neurovascular changes up to 5 weeks postinjury.