1Boston University School of Medicine, Boston, MA, USA, 2Saint Vincent Hospital, Worcester, MA, USA.
Objective:
Endoscopic vein harvest (EVH) is standard of care for CABG in the US, but recent comparisons to open harvest suggest worse graft patency. This may be due to compromised conduit integrity during the learning curve for EVH. To test this hypothesis, we analyzed the quality of conduits procured by technicians with varying EVH experience.
Method:
EVH was performed during CABG by “experienced” (>1000 total cases, >30/month) vs. “novice” (<100 cases, <3/month) technicians. After EVH but prior to saline distension, vein conduits were examined ex vivo for evidence of injury using intraoperative imaging with a 1F optical coherence tomography catheter (OCT, Lightlab Imaging Corp). Conduits harvested using an open technique were imaged as a control (n=10). Surplus segments of conduits from all 3 group were analyzed histologically for endothelial integrity and for tissue factor activity using a customized assay.
Results:
Conduits in the experienced (n=62) vs. novice (n=21) groups had similar total length (33 vs. 34 cm) and harvesting times (32.4 vs. 31.8 minutes). OCT imaging detected injury to conduits in both EVH groups with a similar distribution between adventitial disruption (62%, FigA), intimal tears at branch points (23%, FigB) and dissections (15%, FigC). However, veins procured by experienced harvesters showed a lower incidence of each of these types of injury (branch ostia: 1.0±1.0 vs. 2.1±1.9 tears/vein, p<0.03; adventitia: 2.7 ±2.6 vs. 4.9± 4.5 tears/vein, p=0.05; dissection: 0.7±1.2 vs. 0.9±0.9/vein, p=NS) resulting in 4.4± 3.1 vs. 7.9± 4.6 total abnormalities noted per vein (p=0.005). These injuries were rare in the open control group (0.4± 1.5 total abnormalities/vein). Percent endothelial integrity on histology and tissue factor activity showed significant correlations with the number of abnormalities noted on OCT imaging (R=-0.5, p<0.02 and R=0.4, p=0.03).
Conclusion:
Intraoperative OCT imaging confirmed a significantly higher incidence of conduit injury when EVH is performed by inexperienced technicians. This strongly suggests that the learning curve for EVH should be monitored using intraoperative imaging in order to optimize the safety of EVH.
Back to 2010 Annual Meeting
Back to Cardiac Track Program