Evaluation of fibrin seal in animal experiments

This paper presents experimental investigations to evaluate fibrin seal for bleeding control under systemic heparinization as well as some of the benefits and limits of fibrin-presealing vascular prostheses. Local hemostasis using fibrin seal plus collagen fleece was achieved in 3 standardized sources of bleeding produced in mongrel dogs under full heparinization. Water porosity was measured in 3 standard prosthetic materials of different porosity. It could be shown that all graft types investigated were sufficiently sealed up to a pressure of 600 mmHg. The influence of fibrinolysis on the stability of the fibrin network in vascular grafts was tested by in vitro experiments using urokinase incubation. While water permeability increased in fibrin-sealed fabric without aprotinin added, no fibrinolysis-induced leakage was observed in those exposed to aprotinin. Surface thrombogenicity of the fibrin-sealed grafts was higher than in blood-preclotted prostheses, if not rinsed with isotonic saline. After rinsing, thrombogenicity decreased below values obtained in grafts preclotted conventionally. Survival studies in animals show no difference between blood-preclotted and fibrin-presealed prostheses both 3 and 7 days after implantation.