Preservation of endothelial vascular function of saphenous vein grafts after long-time storage with a recently developed potassium-chloride and N-acetylhistidine enriched storage solution.
OBJECTIVE
Saphenous vein grafts are still commonly used in cardiac, vessel and also in transplant surgery. In cardiac surgery, a desperate graft situation could force to keep nonutilized explanted vein segments after CABG in reserve for case of early graft failure. Historically there were no options for adequate long-time graft storage protecting the endothelial layer with its important antithrombotic and immunosuppressive functional aspects. Commonly isotonic saline solution (sodium chloride [NaCl]) has been used as a storing solution in this case. We investigated the impact of long-time storage in NaCl and a recently developed potassium-chloride and N-acetylhistidine enriched storage solution (TiProtec, Dr. Köhler Chemie, Germany) on endothelial function of saphenous veins.


METHODS
Saphenous vein segments (n = 19) were intraoperatively isolated and stored for 24 and 96 hours. The segments were examined in a Mulvany-myograph to assess vessel function. Following preconstriction with norepinephrine, dose-response curves were assessed for relaxation with bradykinin and sodium-nitroprusside. We compared developed maximum wall tension and endothelial cell and smooth muscle cell (SMC) dependent vasodilatory function.


RESULTS
Maximum vessel wall tension was significantly better preserved in TiProtec-stored vessels after 24 h in comparison to segments stored in NaCl (5.11 ± 4.79 mN/mm vs. 2.48 ± 2.43 mN/mm; p = 0.033) and 96 h (4.94 ± 2.82 mN/mm vs. 2.80 ± 1.76 mN/mm; p = 0.042). Likewise endothelium-derived vasodilatory function was maintained significantly after 24 hours in TiProtec-stored vessels (36.9 ± 2.6% vs. 11.8 ± 30.9%; p = 0.005). After 96 hours, endothelium-dependent vascular function was nearly abolished in NaCl-stored vessels, but largely preserved in TiProtec-stored segments (20.6 ± 2.9% vs. 1.9 ± 4.3% in NaCl; p = 0.015). Sodium nitroprusside-mediated SMC-vasodilatory function was better maintained after 24 hours of storage in TiProtec group (88.8 ± 6.4% vs. 61.3 ± 8.2%; p = 0.009). After 96 hours of storage, SMC relaxation did not significantly differ between both storage groups which might be due to a distinct reduction of contractile function in NaCl-stored vessels (98.6 ± 5.0% and 77.9 ± 10.5% for Tiprotec and NaCl, respectively).


CONCLUSIONS
Vessel functions comprising contraction, endothelium-dependent and -independent vasodilatation are significantly reduced following 24 hours of cold storage in NaCl. After 96 hours of storage in NaCl these functions are nearly totally abolished. TiProtec is able to largely reduce this loss of function during cold storage. Therefore, TiProtec is a feasible option for longer term storage of saphenous vein grafts in CABG vessel and transplant surgery.
Department for Cardiac Surgery, University Heart Center Dresden, Dresden, Germany.
Manuel
M
Wilbring
Sems Malte
SM
Tugtekin
Birgit
B
Zatschler
Annette
A
Ebner
Hermann
H
Reichenspurner
Utz
U
Kappert
Klaus
K
Matschke
Andreas
A
Deussen
D000368:Aged; D003080:Cold Temperature; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000637:transplantation; D005260:Female; D006639:Histidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D007552:Isotonic Solutions; D008297:Male; D008875:Middle Aged; D009926:Organ Preservation / Q000379:methods*; D019188:Organ Preservation Solutions / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology*; D012501:Saphenous Vein / Q000187:drug effects* / Q000637:transplantation; D012965:Sodium Chloride / Q000494:pharmacology; D013997:Time Factors; D020858:Tissue and Organ Harvesting; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
D007552:Isotonic Solutions; D019188:Organ Preservation Solutions; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D012965:Sodium Chloride; D006639:Histidine; D011189:Potassium Chloride; C023495:N-acetylhistidine