Hemostatic efficacy of a novel, PEG-coated collagen pad in clinically relevant animal models.

PURPOSE: Currently available hemostatic pads are effective in treating oozing bleeds, but otherwise ineffective in more severe bleeding. This study investigates the hemostatic efficacy of a new hemostatic pad with advanced sealing properties using protein-reactive polyethylene glycol-coated collagen (PCC, Hemopatch) versus an oxidized regenerated cellulose (ORC, Tabotamp/Surgicel Original) in a leporine arterial bleeding model of vascular reconstruction and a porcine hepatic model of general surgery. METHODS: In both models, paired lesions were created and treated according to a randomized scheme and evaluated up to 10 min after application (40 lesions/group/model). Arterial needle holes were created in the femoral arteries of anesthetized rabbits and hepatic lesions were created into hepatic parenchyma of anesthetized pigs. Both models were heparinized to mimic clinical comorbidity. RESULTS: In the leporine vascular surgical model, PCC provided superior hemostatic success compared to ORC at 2 min (Odds Ratio of Success: 85, 95% CI: 25.8-282) and similar hemostatic success at 10 min. In the porcine hepatic model, PCC provided superior hemostatic success compared to ORC at 2 (98 vs 55%, P < 0.001), 3 (93 vs 65%, P < 0.001), 4 (98 vs 68%, P < 0.001) and 5 min (95 vs 80%, P < 0.001), but similar hemostatic success at 8 and 10 min. DISCUSSION: PCC provided 75.4% greater hemostatic success at 2 min in the arterial model and was at least 100 times more likely to be hemostat effective at 2 min in the hepatic model than ORC. CONCLUSIONS: PCC provided faster hemostasis than ORC in a vascular and hepatic surgical model with impaired coagulation.

Fibrin chain cross-linking, fibrinolysis, and in vivo sealing efficacy of differently structured fibrin sealants.

In this study, we compared the sealing characteristics and efficacy of a fibrin sealant with reduced plasminogen (FS-rplg) and a fibrin sealant with aprotinin as a fibrinolysis inhibitor (FS-apr). The relevant sealing characteristics including clot structure, fibrin chain cross-linking, and clot lysis were tested in the laboratory. The sealing efficacy was then investigated in a follow-up animal model to determine differences in the in vivo sealing properties. A total of 46 animals were available for the final analysis with 23 animals in each treatment arm. In conclusion, we saw differences in vitro between FS-rplg and FS-apr in ultrastructure and α-chain cross-linking rates as well as in the rate of fibrinolysis. These differences may explain the significantly enhanced sealing efficacy in FS-apr compared to FS-rplg shown in vivo in a rabbit intestinal model.

Biochemical characterization of autologous fibrin sealants produced by CryoSeal and Vivostat in comparison to the homologous fibrin sealant product Tissucol/Tisseel.

Different principles for production of "autologous fibrin sealant" have been established, and commercial devices employing these methods are nowadays available and used in clinical routine. Users might anticipate for these autologous fibrin sealants features comparable to commercial homologous fibrin sealants, used in surgical routine for many years. However, only little is known about biochemical properties, formation, cross-linking and stability of fibrin sealant clots produced for autologous use with the aid of commercially available devices. We have investigated protein composition, formation and stability of clots obtained from autologuous fibrin sealants produced with commercially available devices (CryoSeal and Vivostat) and compared these parameters to those of the industrially produced homologous fibrin sealant Tissucol/Tisseel. The CryoSeal product is a mixture of many plasma proteins; the Vivostat product and Tissucol/Tisseel appear as comparatively pure plasma derivatives. The products differ in their protein composition and concentrations, including their concentration in fibrin. Significant fibrin alpha and gamma-chain cross-linking by FXIIIa occurs only in Tissucol/Tisseel clots. In test tubes CryoSeal and Vivostat (tranexamic acid-free formulation) fibrin clots liquefy within 1-2 days, but Vivostat (tranexamic acid containing formulation) clots were stable for 4 days and showed partial liquefaction after 5 days. Tissucol/Tisseel clots, containing the protease inhibitor aprotinin, appeared unchanged over the observation period of 5 days. In an in vitro model mimicking in vivo conditions (diffusion of protease inhibitors and proteolytic digestion) clot liquefaction occurs at day 1 for all autologous fibrin sealants clots, with an observable delay for the tranexamic acid containing Vivostat, and day 5 for Tissucol/Tisseel clots. Characterization of the CryoSeal and Vivostat fibrin sealants and Tissucol/Tisseel and their performance show a clear difference in biochemical properties.