Objectives: Unregulated intraoperative distension of human saphenous vein (SV) graft leads to supraphysiologic luminal pressures and causes acute physiologic and cellular injury to the conduit. The effect of distension on tissue viscoelasticity, a biophysical property critical to a successful graft, is not well described. In this investigation, we quantify the loss of viscoelasticity in SV deformed by distension and compare the results to tissue distended in a pressure-controlled fashion. Materials and Methods: Unmanipulated porcine SV was used as a control or distended without regulation and distended with an in-line pressure release valve (PRV). Rings were cut from these tissues and suspended on a muscle bath. Force versus time tracings of tissue constricted with KCl (110 mM) and relaxed with sodium nitroprusside (SNP) were fit to the Hill model of viscoelasticity, using mean absolute error (MAE) and r2-goodness of fit as measures of conformity. Results: One-way ANOVA analysis demonstrated that, in tissue distended manually, the MAE was significantly greater and the r2-goodness of fit was significantly lower than both undistended tissues and tissues distended with a PRV (p<0.05) in KCl-induced vasoconstriction and SNP-induced vasodilation. Conclusions: Unregulated manual distension of SV graft causes loss of viscoelasticity and such loss may be mitigated with the use of an in-line PRV.
Bibliographical noteFunding Information:
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: National Institutes of Health grant R01HL70715-09 for design and conduct of the study, collection, management, analysis or interpretation of the data or review and approval of the manuscript (Dr Brophy) and National Institutes of Health grant R01HL105731-01A1 for design and conduct of the study, collection, management, analysis and interpretation of the data and preparation and approval of the manuscript (Dr Cheung-Flynn).
- bypass grafts
- saphenous vein