Mechanical Properties of Surgical Glues Used in Aortic Root Replacement

Background. Surgical glues are used in mechanical, stentless bioprosthetic, and homograft aortic root replacements to seal and reinforce anastomotic suture lines. The aortic root normally undergoes substantial physiologic dilation and may be affected by the stiffness of applied sealants. We determined the material properties of four common commercial glues, comparing them with known properties of aortic root replacements. Methods. Samples of BioGlue (CryoLife, Inc, Kennesaw, GA), CoSeal (Baxter Healthcare International, Palo Alto, CA), Tisseel (Baxter Healthcare Corp, Glendale, CA), and Crosseal (OMRIX Biopharmaceuticals, Inc, New York, NY) sealants underwent biaxial tensile testing. A Hookean strain energy function was fit to the stress-strain response of each sample, and the Young's modulus was obtained for comparison of material stiffness. Results. Sealants demonstrate a relatively linear response to loading; mean elastic moduli for BioGlue (3,122.04 +/- 1,639.68 kPa), CoSeal (100.02 +/- 67.60 kPa), Tisseel (102.59 +/- 41.13 kPa), and Crosseal (53.56 +/- 32.59 kPa) varied greatly. CoSeal and Tisseel have no significant difference in stiffness (p = 0.897) while Crosseal is more compliant than Tisseel (p = 0.004) and CoSeal (p = 0.055). BioGlue is stiffer than CoSeal, Tisseel, and Crosseal (p < 0.001). Furthermore, BioGlue is much stiffer than cited properties of Dacron grafts, glutaraldehyde-fixed porcine roots, and human aortic tissue. However, CoSeal and Tisseel are much more compliant than the aortic root conduits. Conclusions. BioGlue is much less compliant than the other sealants studied and materials available for aortic root replacement. A surgeon's choice of glue should be determined by stiffness as well as sealant efficacy. Sealants with greater stiffness than aortic root replacement material may restrict normal physiologic dilation and cause anastomotic strictures.