Heparinized blood better preserves cellular energy charge and vascular functions of intraoperatively stored saphenous vein grafts in comparison to isotonic sodium-chloride-solution

Abstract

OBJECTIVE: Several studies have addressed the optimal storage conditions for vascular grafts during surgery. The results remain contradictionary. This may be attributed to the fact, that the various vascular beds have a different sensitivity to storage. We analyzed the impact of storage in isotonic saline solution (NaCl) or heparinized blood the vascular functions of human saphenous vein grafts. Special care was taken to choose storage conditions which are relevant for intraoperative storage of a saphenous vein graft in a setting of coronary artery bypass grafting with vein and internal mammary artery as grafts. METHODS: Intraoperatively isolated V. saphena-segments (n = 36) were stored in NaCl or heparinized blood for approximately 30 minutes at room temperature. Subsequently, the segments were examined in a Mulvany-myograph. Following preconstriction with norepinephrine, concentration-relaxation curves were assessed for bradykinin and sodium-nitroprusside to assess developed vessel-wall tension as well as endothelium-and smooth-muscle-cell dependent vasorelaxation. The availability of adenosintriphosphate (energy charge) was determined based on liquid chromatography measurements of nucleotide tissue levels. RESULTS: Mean storage time was 27.4 ± 2.4 min in NaCl-and 26.3 ± 2.7 min in blood-group, respectively. After this period, receptor-dependent and-independent maximum of developed vessel wall tension was significantly reduced in NaCl-group (p = 0.05 and p = 0.045, respectively). Furthermore, the energy charge was significantly (p = 0.046) better preserved after blood storage (74 ± 1%) in comparison to NaCl-group (68 ± 2%). Endothelium-induced vasodilatation in response to bradykinin reached only 12.3 ± 2.5% in NaCl-group, but 19.3 ± 5.2% in blood-group (p = 0.033). Alike, EC 50 -concentration of bradykinin for half-maximal relaxation was significantly lower in blood-than in NaCl-group (log EC 50 −7.08 ± 0.3 and −5.91 ± 0.4; respectively; p = 0.046). Endothelium-independent smooth muscle relaxation in response to sodium-nitroprusside was not different between both groups. CONCLUSION: Heparinized blood better preserves vascular contractile and endothelial functions of the saphenous vein graft. Storage in NaCl rapidly compromises vascular functions and impaires cellular energy. NaCl should no longer be recommended for intraoperative storage of harvested V. saphena grafts.

Cardioplegic storage solution: Is it the guardian of saphenous vein graft endothelium?

“…Endothelial integrity preventing early and late graft failure is critical for SVG function 3,7 . Several intraoperative factors, such as vessel harvesting technique, manipulation, and mechanical distension of venous grafts, quality of target vessel and exposure to high arterial pressures and turbulent flow have been accused to impair endothelial integrity thus triggering graft failure 1,9 .…”

“…Consequently, there is no consensus concerning the optimal storage solution in daily practice, the choice of which is subjected to the surgeon and widely varies between different patients 1,7 . The most frequently used storage solution is NS/PSS (sodium chloride [0.9% NaCl]) 3 . Alternative storage solutions commonly used in cardiac surgery include, autologous heparinized blood (AHB), histidine‐tryptophan‐ketoglutarate, RL, University of Wisconsin solution (UWS), GALA solution (glutathione, ascorbic acid, l ‐arginine) and other solutions containing ions for pH buffering, antioxidants, high‐molecular‐weight molecules, and an ionic composition similar to that of intracellular fluid 3,5,7,9,15 …”

“…Although PSS still remains the most frequently used storage media, 5 there is an endless debate whether the blood or saline is superior. The first study showing the superiority of AHB in terms of storage of venous endothelium compared with NS storage solution at the same temperature was conducted in 1980 by Gundry et al 16 Many other studies confirmed the superiority of storage in autologous blood with regard to the minimization of endothelial damage and preservation of contraction and relaxation properties of human vein grafts 3,17‐21 . However, other studies failed to prove the superiority of autologous blood over crystalloid storage solutions 7,21‐24 .…”

“…Coronary artery disease (CAD) is the leading cause of death worldwide 1 . Globally performed in 800 000 cases per year, 2 coronary artery bypass grafting (CABG) is currently the treatment of choice regarding myocardial revascularization against multivessel CAD 3 . Saphenous vein grafts (SVGs) are still the most widely used conduits during CABG to achieve complete revascularization, 2,4 especially in the elderly 3,5 .…”

The effect of storage solutions, gene therapy, and antiproliferative agents on endothelial function and saphenous vein graft patency

“…Four other studies failed to find any significant superiority of AHB over saline in preserving graft function. More recently, Wilbring et al reported that AHB preserves vascular contractile and endothelial functions of the SVG. Storage in NS rapidly compromises vascular functions and impairs cellular energy.…”