Metabolic damage to human saphenous vein during preparation for coronary artery bypass grafting

Abstract

Segments of saphenous vein from patients undergoing coronary artery by-pass graft surgery were frozen in liquid nitrogen immediately on dissection (control), after stripping of the adventitia and side branch ligation (manipulation), after distention with blood (distention), or at completion of the last proximal anastomosis (prepared vein). Vein was stored during the operation in patient's heparinised arterial blood at room temperature. Frozen vein was extracted with perchloric acid. ATP, ADP, and AMP, adenosine, inosine and hypoxanthine concentrations were measured by high pressure liquid chromatography. Prepared vein had ca 50% lower ATP concentrations and ATP/ADP ratio than control vein, higher concentrations of inosine and hypoxanthine and lower concentrations of AMP and adenosine. ATP concentration and ATP/ADP ratio did not correlate with the time elapsed between dissection and freezing of the prepared vein. The characteristic changes seen in prepared vein were not seen when control vein was simply stored in arterial blood at 23 degrees C, in normal saline at 23 degrees C or 4 degrees C, in Krebs-Ringer bicarbonate buffer at 37 degrees C or at St Thomas's Hospital cardioplegic solution at 4 degrees C. Distention with unlimited pressure did not distension at less than 300 mmHg gave rise to the same changes in ATP concentration and ATP/ADP ratio as in the prepared vein. These results show that vein suffered metabolic changes during preparation for bypass grafting and suggest that uncontrolled distention may contribute to these changes. Such biochemical measurements provide a quantitative estimate of tissue damage and allow objective comparison of different preparative techniques.

Manual pressure distension of the human saphenous vein changes its biomechanical properties—implication for coronary artery bypass grafting

“…Routine anaesthetic and surgical procedures were done. The saphenous vein was removed through an incision over the vein using conventional open technique (Angelini et al, 1985). All veins appeared without any macroscopic pathology.…”

“…Previous studies have demonstrated that uncontrolled manual distension of the saphenous vein structurally and functionally damage the endothelium (Angelini et al, 1987a, b;Chello et al, 2003;Johnson et al, 2001;Mills and Everson, 1995;Svendsen et al, 1986;Thatte and Khuri, 2001), muscle (Angelini et al, 1985(Angelini et al, , 1987aCornelissen et al, 2004;George et al, 1997;O'Brien et al, 1998), and interstitium (Kennedy et al, 1989a, b). In the present study, the wall thickness and wall area were largest in the saphenous vein with uncontrolled manual distension.…”

“…Several studies have demonstrated that abnormal distension procedures affect the contractility of the vessel (Dhein et al, 1991), damage the integrity of the endothelium (Chester et al, 1998;Sayers et al, 1992), increase expression of endothelial adhesion molecules (Chello et al, 2003) and reduce the release of nitric oxide, prostacyclin and the ATP/ADP ratio in the media (Angelini et al, 1985). The biomechanical properties of the vein may relate to these changes, and changes in the biomechanical properties may relate to early and late pathological changes in the vein graft such as early thrombosis, intimal proliferation and late occlusion of the vein graft (Gusic et al, 2005a, b).…”

Evaluation of endoscopic vein extraction on structural and functional viability of saphenous vein endothelium

“…Using epifluorescence multiphoton imaging techniques, we have previously shown that the pH, temperature, SV distention, and composition of storage solution can affect the endothelial viability and function [4,12-15]. Similarly, surgical manipulation can also damage the endothelium of SV grafts, increasing the risk of vasospasm, thrombogenesis, occlusive intimal hyperplasia, and stenosis [4,5,10,11]. …”

Traditional graft preparation decreases physiologic responses, diminishes viscoelasticity, and reduces cellular viability of the conduit: A porcine saphenous vein model

“…12, 31–36 The impact of unregulated distension on the endothelial layer is more pronounced. Peak distension pressure is proportional to endothelial loss and dysfunction in human SV.…”