Untersuchung zum vaskulären Remodelling in venösen Bypassgefäßen nach Lagerung in verschiedenen Gefäßprotektionslösungen im Gefäßtransplantationsmodell der Ratte

by Manuel J. Santander
Doctoral thesis
Date of Examination:2025-11-24
Date of issue:2025-11-20
Advisor:Prof. Dr. Ingo Kutschka
Referee:PD Dr. Anke Zieseniß
Referee:PD Dr. Michael Didié
Persistent Address: http://dx.doi.org/10.53846/goediss-11631

 

 

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Abstract

English

After the establishment of aortocoronary bypass surgery for the treatment of advanced coronary artery disease, the great saphenous vein, together with the internal mammary artery, became the principal conduit for coronary bypass grafting. Compared with the internal mammary artery, the long-term patency of venous grafts is limited. Consequently, there is great interest in investigating the pathophysiology of graft failure in order to develop strategies to counteract it and thereby improve clinical outcomes. In this context, several approaches have been introduced, including the “no-touch” harvesting technique, various storage and preservation methods, meticulous anastomotic technique, and postoperative pharmacological therapy. Among the storage solutions studied—such as specific buffered solutions, histidine-tryptophan-ketoglutarate (HTK) solution, sodium chloride, and heparinized autologous blood—the results remain controversial. This has led to the development of alternative storage and protection solutions such as TiProtec and DuraGraft. Since no consensus exists regarding the most suitable storage solution, a long-term in vitro study comparing three solutions (sodium chloride, DuraGraft, and TiProtec) was conducted. For this purpose, the right internal jugular vein of Wistar rats was harvested and stored for 120 minutes in one of the respective solutions. The graft was then interposed into the infrarenal aorta, while in a sham group the vein was implanted directly without prior storage. After an observation period of 16 weeks, the rats were euthanized, and the venous grafts were divided into two rings for further analysis. One ring was used for vascular function testing with a myograph, while the other underwent immunohistochemical and immunofluorescence-based examinations. The present results demonstrate that, in functional measurements of vasoconstriction and vasodilation, the TiProtec solution achieved the best outcomes. Histomorphological analysis revealed significant changes in vessel size and wall structure, attributable to remodeling under high wall tension. However, no clear superiority of one protection solution over another could be established.
Keywords: Graft patency; Coronary artery bypass grafting; Storage solution