Endothelial damage of the venous graft in CABG *1Influence of solutions used for storage and rinsing on endothelial function

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)

Even short-time storage in physiological saline solution impairs endothelial vascular function of saphenous vein grafts

“…This is in accord with the results of other groups [16,17]. Zerkowski et al showed a greater degree of dissociation of the endothelial cells and an altered surface structure in saline solution-stored vessel segments studied with scanning electron microscopy [17]. In this context, it is noted here that the frequently added heparin may exert additional toxic effects on the endothelial layer and therefore should be avoided [18,19].…”

“…Frequently used options are HTK solution, Ringer's lactate solution, PSS, or blood augmented with heparin [16]. Several studies have indicated the superiority of HTK solution or heparinized blood in comparison to the reported alternatives [16,17]. However, more recently, a poor preservation of HTK solution with respect to coronary artery function has been reported [20].…”

“…An intact endothelial layer plays a decisive role for whole graft function by influencing the vascular reactivity by paracrine secretion of vasoactive substances [17]. Following this, saphenous vein grafts are not simply passive (in the sense of unreactive) conduits.…”

Noradrenaline-induced contraction of human saphenous vein and human internal mammary artery: involvement of different α-adrenoceptor subtypes

“…Saphenous veins and internal mammary arteries were obtained during cardiopulmonary bypass. Immediately after excision, all specimens were placed in autologous heparinized whole blood (Zerkowski et al 1993) and kept overnight in the refrigerator.…”

Lidocaine relaxation in isolated rat aortic rings is enhanced by endothelial removal: possible role of Kv, KATP channels and A2a receptor crosstalk

“…The aortic rings were then washed with freshly prepared Krebs Henseleit buffer pH 7.4 and the tension was readjusted to 1.5 g tension. Each preparation was sub-maximally contracted using 3 μl of 0.1 mM NE (0.3 μM final concentration) [15, 32]. Those aortic rings that failed to contract were discarded.…”