Physical characteristics of Vivostat patient-derived sealant. Implications for clinical use.

This study compared the physical characteristics of Vivostat patient-derived sealant with two conventional fibrin sealants, Tissucol and Beriplast. Vivostat sealant exhibited greater elasticity without compromising tensile strength. Vivostat sealant polymerised at low temperatures (4 and 25 degrees C) or at high temperature (70 degrees C) exhibited similar viscoelastic properties as when polymerised at normal physiological temperature (37 degrees C). Vivostat fibrin I solution can be stored at room temperature for up to 8 h without affecting the mechanical properties of the derived sealant. These physical characteristics of Vivostat patient-derived sealant suggest that it may have suitable stability and performance characteristics for use in a wide range of surgical procedures.

Comparative kinetics of polymerisation of three fibrin sealants and influence on timing of tissue adhesion.

The clinical performance of fibrin sealants may be influenced by physical properties such as elasticity, tensile strength, and ability to adhere to human tissue. These properties are related to the internal structure of the fibrin sealant that builds as it polymerises. Analysis of the minimum polymerisation time to achieve a functional fibrin clot is clinically important. Instant tissue-fibrin sealant adhesion is desirable to ensure that the fibrin sealant functions on contact and remains at the site of application without being washed away by blood or displaced by movement of the target tissue (e.g., the heart or lungs). The physical characteristics of fibrin sealants are related to the extent of fibrin cross-linking. Determination of the polymerisation rate allows calculation of the minimum time required to produce a functional clot. The adhesion characteristics to vital human tissue and kinetics of polymerisation between 20 and 300 seconds postapplication of Vivostat system patient-derived sealant have been analysed and compared to those obtained for two conventional fibrin sealants, Tissucol and Beriplast. Mathematical analysis of the experimental data revealed that polymerisation of Vivostat sealant followed first-order kinetics, whereas that of Beriplast and Tissucol followed second-order kinetics. This study demonstrates that Vivostat sealant polymerises faster than these other conventional fibrin sealants.

Development of a model for measurement of adhesion strength of fibrin sealant to human tissue.

It is crucial for the surgeon to know the physical properties of a surgical sealant. Current test methods of fibrin sealant involving animal testing or in vitro testing of sealant using artificial substrates have little clinical relevance. Most of these test methods also lack accuracy and reproducibility. A new model was developed for testing strength and in vitro adhesion of fibrin sealant to vital human tissue using fresh vein leftover from coronary artery bypass grafting. The vein leftover was cut into samples and fastened in a tensiometer linked to a computer. Patient-derived fibrin sealant (0.1 ml) was applied to the tissue, and the surfaces of the tissue samples were held together for 5 min, and then automatically pulled apart by the tensiometer. Data were generated in a load cell and recorded and analysed by the computer. The reproducibility for the adhesion strength was 6.6%, adhesion energy 9.8%, and elongation at break 8.4%. The method has been considered ethical and has good reproducibility. The method can be used for standardised measurements and comparison of different types of fibrin sealant without the sacrifice of animals.