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Endothelial damage of the venous graft in CABG. Influence of solutions used for storage and rinsing on endothelial
H R Zerkowski1, M Knocks, M A Konerding
1Universitätsklinikum Essen, Germany.
Insights
Storing saphenous vein grafts (SVG) in heparinized whole blood (HWB) preserves endothelial function, crucial for preventing early graft occlusion after coronary artery bypass grafting (CABG). This finding highlights optimal graft preservation techniques.
Area of Science:
- Vascular Surgery
- Cardiovascular Research
- Biomedical Engineering
Background:
- Early graft occlusion after aortocoronary revascularization using saphenous vein grafts (SVG) is a significant clinical problem.
- Endothelial lesions, mechanical or biochemical, are primary causes of graft failure.
- Morphological examination of endothelium does not assess its functional integrity.
Purpose of the Study:
- To evaluate the impact of different storage solutions on the functional characteristics of SVG endothelium.
- To identify optimal preservation methods to maintain endothelial function and potentially reduce early graft occlusion.
Main Methods:
- In vitro study on macroscopically intact SVG segments from 30 male patients undergoing CABG.
- Segments were stored in heparinized whole blood (HWB), Bretschneider's solution (HTK), human albumin solution (HAS), or Ringer's solution (RS) for 60 minutes.
- Endothelial function assessed by measuring relaxation of pre-contracted vein segments in response to acetylcholine (ACh) after noradrenaline (NE) stimulation.
Main Results:
- Only SVG segments stored in HWB demonstrated maximal contractions to NE comparable to untreated controls.
- These HWB-stored segments also exhibited relaxation in response to ACh, indicating preserved endothelial function.
- Other storage solutions (HTK, HAS, RS) did not maintain the contractile and relaxant responses of the endothelium.
Conclusions:
- Heparinized whole blood (HWB) is a superior storage solution for maintaining saphenous vein graft (SVG) endothelial function compared to HTK, HAS, and RS.
- Preserving endothelial function through optimal storage is critical for improving outcomes in coronary artery bypass grafting (CABG).
- Further research should focus on clinical validation of HWB for SVG preservation.
Abstract:
A significant proportion of early graft occlusions after aortocoronary revascularization using autologous saphenous vein grafts (SVG) are due to mechanical and/or metabolic or biochemical endothelial lesions. The morphological examination of the endothelium, usually carried out using light microscopy or by various types of scanning electron microscopy (SEM), does not give any indication of the functioning of the endothelium (E). Functionally intact E is capable of producing endothelium-derived relaxing factor (EDRF); a practicable in vitro test is the relaxation of pre-contracted vein segments (VS) in response to acetylcholine (ACh) application. To study the effect of the solution used to rinse and store the SVG between removal and implantation on the functional characteristics of the E, we performed in vitro tests on macroscopically intact VS removed from the saphenous vein of 30 male patients who underwent elective CABG surgery. Isolated VS rings were incubated for 60 min in heparinized whole blood (HWB), Bretschneider's cardioplegic solution (HTK), human albumin solution (HAS), or Ringer's solution (RS) and compared with the results obtained immediately after the removal of untreated control samples (C) taken from the same patients. After equilibration in carbogen aerated Krebs-Henseleit solution and precontraction by 3 x 10(-7) M noradrenaline (NE), relaxation induced by 10(-6) M ACh was measured. Only the samples stored in HWB (13.4 +/- 0.4 mN) showed similar maximal contractions with NE to those in the control group (14.4 +/- 0.5 mN), i.e. all those segments which showed both contractions with NE and relaxation with ACh.(ABSTRACT TRUNCATED AT 250 WORDS)