welcomes you to the new, improved website!The authors conducted a randomized prospective study comparing 3 methods of SVG harvesting in 156 patients. The 3 methods compared were as follows: Conventional (C)–stripped and distended veins; Intermediate (IM)–stripped but not distended veins; and, No Touch (NT)–neither stripped nor distended but harvested on a pedicle. In comparing the C (n=27) and NT (n=27) groups that were available at a mean of 16 years, crude SVG patency was 64% in C vs. 83% in NT (p=0.03). The latter was comparable to the observed LIMA patency, 88%.
You are here:
The no-touch saphenous vein for CABG maintains a patency after 16 years comparable to the left internal thoracic artery. A Randomized Trial
Submitted by: Arie Blitz
Source: Journal of Thoracic and Cardiovascular Surgery
Keywords:
Author(s): N. Samano, H. Geijer, M. Liden, S. Fremes, L. Bodin, D. Souza
6 Comments
Is there enough evidence here to start harvesting the SVG en-bloc? If so, what are the implications for EVH?
I get very concerned when I read studies like this. We have results on 30% of the veins only (Not to mention this is a very small study anyway). We have no detailed data or randomisation of target vessels. The target is the biggest predictor of patency. This study is of very limited value to myself.
Dr. Kolocassides,
I agree with you that there are definitely weaknesses of the published study. Part of the issue with the small sample size in comparison to the original group is the long-term follow-up, during which one would expect attrition from mortality. In such a study it would be difficult to randomize the target vessels, since the subjects themselves were randomized to one of the harvest methods. Nonetheless, I do agree that the small sample size and the failure to control for the target vessels do weaken the study’s impact.
Thank you for your important comments. I postponed commenting on your remarks until the article was published and I hope you have read the full text of the study.
Answering the first question by Dr. Blitz about if there is enough evidence to start harvesting the saphenous vein graft en-bloc and the implications for EVH? I think there is enough evidence. There are more than 30 publications that support the different advantages of the no-touch saphenous vein harvesting technique. We definitely recognize the advantages of minimal invasive techniques in harvesting the saphenous vein especially in terms of wound healing. Mannion et al. showed in a recent study that the no-touch vein grafts which were harvested by an open technique had a higher patency rate compared to the traditional endoscopic harvested veins but the NT group had significantly higher harvest site complications (1). The ambition is to develop an endoscopic or minimally invasive harvesting technique for the no-touch vein grafts and to start a study comparing both the endoscopic and open techniques for the no-touch vein grafts.
In regard to Dr. Kolocassides comments, 52% (27/52) of the patients initially included in the conventional and no-touch groups were included in the 16 years follow-up and regarding the number of grafts, totally 59% (147/251) of the grafts were included in the last follow-up. Concerning detailed data or randomization of target vessels, the patients were randomized into the different groups and all target vessel and vein graft characteristics in relation to patency are reviewed in detail in table 3. Thereby describing the target vessel size and quality during the 3 follow-ups; 1.5, 8.5 and 16 years.
Lastly in reply to Dr. Blitz about failure to control for the target vessels, in table 4 we performed a Cox proportional hazard regression model for analysis of time to occlusion including all the vein grafts (n=251) in both the conventional and no-touch groups using a multifactor model where the harvesting technique, graft flow, target vessel diameter and harvesting site were included in the analysis. All included factors fulfill the proportionality assumption of the Cox proportional hazard model.
References:
1. Mannion JD, Marelli D, Brandt T, Stallings M, Cirks J, Dreifaldt M, et al. “No-touch” versus “endo” vein harvest: early patency on symptom-directed catheterization and harvest site complications. Innovations (Phila). 2014;9(4):306-11.
I humbling comment here as a CVT PA of 30+ years of vein harvesting experience…i have developed EVH techniques to preserve surrounding tissue…my goal is to preserve 2-5mm of adventitia. That said, i am not sure that the true improvement in vein graft viability lies in the fact that in one group the vein was not prepared until proximally attached first to the aorta…
Thank you for your comments. Preserving the surrounding tissue is one of the most important steps in the no-touch vein harvesting technique. Nonetheless it is not the only step. Minimal manipulation of the vein grafts is mandatory to avoid graft spasm and the need for dilatation, the later causing irreversible damage to the vessel wall and eventually vein graft failure. I thinks it’s very interesting that you harvest the vein with its surrounding tissues. I would love to see a video of your harvesting technique. About your second comment, the fact that the grafts in the conventional group were stored in saline and the grafts in no-touch and intermediate groups were kept in situ until going on bypass was to compare the ischemic storage time between the vein grafts in saline vs. vein grafts in heparinized blood which was first obtained from the aortic cannula before going on bypass and cooling. There was a significant difference in the ischemic storage time between the 2 groups.