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Objective Vasospasm is the primary obstacle to widespread adoption of the radial artery as a conduit in coronary artery bypass grafting. We used optical coherence tomography, a catheter-based intravascular imaging modality, to measure the degree of radial artery spasm induced by means of harvest with electrocautery or a harmonic scalpel in patients undergoing coronary artery bypass grafting. Methods Radial arteries were harvested from 44 consecutive patients with a harmonic scalpel (n = 15) or electrocautery (n = 29). Vessels were imaged before harvesting and after removal from the arm, with saphenous vein tracts serving as internal controls. Optical coherence tomographic findings for the degree of harvesting-induced injury were validated against histologic measures. Results Optical coherence tomographic measures of endovascular dimensions and injury correlated strongly with histologic findings. Mean luminal volume, a measure of vasospasm, decreased significantly less after harvesting with a harmonic scalpel (9% ± 7%) than with electrocautery (35% ± 6%, P = .015). Completely intact intima was present in 11 (73%) of 15 radial arteries harvested with a harmonic scalpel (73%) compared with 9 of 29 arteries harvested by means of electrocautery (31%, P = .011). Intraoperative flow measurements and patency rates at 5 days postoperatively were not significantly different among groups. Conclusions Optical coherence tomography provides a level of speed and accuracy for quantifying endothelial injury and vasospasm that has not been described for any other modality, suggesting potential as an intraoperative quality assurance tool. Our optical coherence tomographic findings suggest that the harmonic scalpel induces less spasm and intimal injury compared with electrocautery.

Objectives Endothelial disruption within saphenous vein and radial artery grafts increases thrombosis risk. However, no clinically applicable method for imaging the intima currently exists. We used a novel infrared imaging technology, optical coherence tomography (OCT; LightLab Imaging, Inc, Westford, Mass), to visualize the intima within harvested conduits. Methods Conduits were procured endoscopically (37 saphenous vein grafts and 8 radial artery grafts) or with the open technique (9 radial artery grafts) from 50 patients. Surplus segments were analyzed by means of OCT for evidence of preexisting pathology or traumatic injury. Focal plaques in radial artery grafts and the intimal hyperplasia area in saphenous vein grafts were quantified as having an intimal/medial thickness ratio of greater than 0.5. Biopsy specimens were obtained for histologic confirmation and to analyze matrix metalloproteinase 2 levels (saphenous vein grafts) and prostacyclin/nitric oxide metabolites (radial artery grafts). Interobserver κ coefficients and a Bland–Altman analysis were used to determine the reproducibility and accuracy of OCT interpretations. Results Radial artery imaging revealed plaque in 76%. Endoscopically harvested vessels showed intraluminal clot (38%) and intimal tears ranging from severe (6%) to mild (88%). In saphenous vein grafts intimal thickening was detected in 86% and intraluminal clotting in 68%. The intimal/medial thickness ratio determined by means of OCT correlated directly with matrix metalloproteinase 2 levels ( R = 0.6804) in saphenous vein grafts and inversely with metabolites of prostacyclin ( R = −0.55) and nitric oxide ( R = −0.58) in radial artery grafts. OCT imaging was reproducible (interobserver κ coefficients of >0.81 for the characterization of plaque types) and showed a strong correlation with histology ( R = 0.8, P Conclusions OCT imaging provides an accurate, real-time, and reproducible means for assessing saphenous vein graft and radial artery graft bypass conduits. As a quality assurance tool, this technology might afford a more objective basis for conduit selection.