OBJECTIVE: The use of the saphenous vein in coronary artery bypass graft surgery is associated with high 1-year occlusion rates of as much as 30%. A new "no-touch" technique of saphenous vein harvesting in which the vein is harvested with a pedicle of surrounding tissue and not distended may result in improved early patency rates. We hypothesize that nitric oxide synthase is better preserved with the no-touch technique, and the aim of this study was the investigation of whether nitric oxide synthase distribution and quantity in saphenous veins harvested with the no-touch technique differ from those veins harvested with the conventional technique. The separate contribution of perivascular tissue removal and distension to alterations in nitric oxide synthase was also studied.

METHODS: Segments of 10 saphenous veins were harvested from 10 patients who underwent coronary artery bypass grafting surgery with the no-touch and conventional techniques. Samples were also taken from segments that were stripped of surrounding tissue but not distended. Nitric oxide synthase distribution was studied with reduced nicotinamide adenine dinucleotide phosphate--diaphorase histochemistry, and staining was quantified with image analysis. Immunohistochemistry was used for the identification of specific nitric oxide synthase isoforms, and immunomarkers were used for the identification of associated cell types.

RESULTS: Nitric oxide synthase content was higher in no-touch vessels as compared with conventionally harvested vessels (35.5%; P <.05, with analysis of variance). This content was associated with endothelial nitric oxide synthase on the lumen while all three isoforms were present in the media. In the intact adventitia of no-touch vessels, all three isoforms of nitric oxide synthase were also present, associated with microvessels and perivascular nerves. Perivascular tissue stripping and venous distension both contribute to the reduced nitric oxide synthase in conventionally harvested veins.

CONCLUSION: The new no-touch technique of saphenous vein harvesting preserves nitric oxide synthase, which suggests that improved nitric oxide availability may be an important mechanism in the success of this technique.

BACKGROUND: The technique of harvesting the saphenous vein for coronary artery bypass grafting influences the fate of vein grafts. The patency rate of a novel "no-touch" technique in which the vein is harvested with a pedicle of surrounding tissue and not distended was compared with two other techniques.

METHODS: One hundred fifty-six patients who underwent coronary artery bypass grafting were randomized to three saphenous vein harvesting groups: group C (conventional)--the vein was stripped, distended, and stored in saline; group I (intermediate)--the vein was stripped, local application of papaverine was used instead of distention, and the vessel was then stored in heparinized blood; and group NT (no-touch)--the vein was harvested with surrounding tissue, not distended, and stored in heparinized blood. Surgical and clinical factors that might influence graft occlusion were recorded. One hundred twenty-seven vein grafts in group C, 116 in group I, and 124 in group NT, as well as 118 left internal mammary artery grafts, were angiographically assessed at 18 months mean follow-up time.

RESULTS: The vein graft patency was 88.9% in group C, 86.2% in group I, and 95.4% in group NT. There was a statistically significant difference between the patency of the single-vein grafts in NT and the other two groups (p = 0.025). The higher the flow, the better the patency irrespective of the technique used. A higher attrition rate was found in vein segments taken from the knee area in group I. Poor vein quality affected patency in all groups. Forty-seven of all 51 sequential grafts (92.2%) were patent. The patency of left internal mammary artery grafts was 108 of 118 (91.5%).

CONCLUSIONS: We conclude that preservation of the surrounding tissue of the saphenous vein using this no-touch technique abolishes venospasm intraoperatively and plays an important role in maintaining vein graft function and patency.