We investigated the effect of a novel surgical preparative technique for human saphenous vein by using the concentration of adenosine triphosphate and the adenosine triphosphate/diphosphate ratio to quantify medial integrity and by using stimulated rates of prostacyclin production to quantify endothelial function. Freshly isolated vein had an adenosine triphosphate concentration of 358 +/- 54 nmol.g-1 wet weight and an adenosine triphosphate/diphosphate ratio of 2.89 +/- 0.13 (n = 12); it produced prostacyclin in response to fluid shear at a rate of 14.3 +/- 2.0 pg.min-1.mg-1 wet weight (n = 12). Surgically prepared vein obtained on completion of the last proximal anastomosis had been distended with the patient's own arterial pressure using a side-arm connected to the aortic cannula. This vein had an adenosine triphosphate concentration of 413 +/- 70 nmol.g-1 wet weight and an adenosine triphosphate/diphosphate ratio of 2.74 +/- 0.44 (n = 11), and it produced prostacyclin at a rate of 13.1 +/- 0.2 pg.min-1.mg-1 wet weight (n = 12). All values were indistinguishable from those in freshly isolated vein. The results demonstrate that this simple technique for distention at arterial pressure preserved medial and endothelial function.