BACKGROUND:
Human saphenous vein (HSV) remains the most widely utilized conduit for vascular bypass procedures. Outcomes remain limited by vein graft failure and intimal hyperplasia. Endothelial function is considered an important determinant of vein graft failure. We have observed significant variability in endothelial function in freshly isolated HSV samples. We therefore evaluated clinical predictors of endothelial function in HSV.
Methods:
We obtained freshly isolated HSV samples from the operating room immediately following harvest from patients undergoing coronary artery bypass procedures from Vanderbilt University Hospital and the Nashville VA Hospital. We obtained HSV samples prior to any intraoperative manipulations. HSV viability, smooth muscle function, and endothelial-dependent relaxation (EDR) were measured in a muscle bath. We collected the following clinical and demographic information: age, height, weight, gender, ethnicity, medical comorbidities, laboratory values (creatinine, HbA1c, lipids), ejection fraction, preoperative medication regimen, and method of vein graft harvest. We performed a univariate and multivariate analysis of predictors of endothelial function in HSV.
Results:
HSV samples were obtained from 149 patients. HSV EDR varied from -11% to 63%. Open harvest was employed for 39 HSV samples, compared with endoscopic harvest in 110 HSV samples. On univariate analysis, only open harvest was a statistically significant predictor of endothelial function (p=0.02): mean HSV EDR was 21.5% in HSV samples harvested open, compared with 15.4% in HSV harvested with an endoscopic technique. HSV EDR was also improved with preoperative aspirin use: mean HSV EDR was 18% in patients with preoperative aspirin use compared with 11.6% in patients who were not administered preoperative aspirin in a multivariate model when controlling for method of vein graft harvest (p=0.05).
Conclusions:
Endoscopic vein graft harvest is associated with endothelial dysfunction in HSV, while preoperative aspirin use is associated with improved endothelial function. Further work will be necessary to determine whether these factors are associated with development of intimal hyperplasia and vein graft failure.
The no-touch saphenous vein should be considered in a risk score of vein graft failure