the great saphenous vein ( gsv ) is the most commonly used conduit for coronary artery bypass grafting ( cabg ) .   the referenced standard method of harvesting the gsv is by way of the open surgical technique . depending on the required graft length , the average incision will vary between 20 and 40 centimetres . however , in the population of patients undergoing cabg , risk factors for impaired wound healing are overrepresented . evaluation of 1577 patients that underwent open gsv harvest for cabg in maastricht , revealed that in 1.5% of patients donor - site infections were diagnosed before discharge . remarkably this figure increases to 4.6% at 30 days followup and 7.3% at 90 days followup . therefore 80% of the donor - site infections are diagnosed after discharge , for instance by the patients general physician or cardiologist . furthermore wound complications are often found to be responsible for additional surgery , prolonged hospital stay , increased hospital costs , and in some cases permanent disability [ 1 , 2 ] . the introduction of endoscopic vein harvesting ( evh ) in 1996 seemed a welcome contribution to achieve goals set in modern cardiac surgery , namely , making cardiac surgery less invasive and promote earlier recovery after surgery . now approximately 15 years after its introduction evh has conquered an important place in standard clinical care ( 80% of the cabg procedures conducted in the usa use evh ) . nevertheless , recent publications have raised doubts whether the quality and durability of an endoscopically harvested vein is comparable with a vein harvested in the traditional open fashion [ 4 , 5 ] . is evh indeed   a blessing in the attempts to make cardiac surgery less invasive or do the recent publications reveal hidden dangers ? this nonsystematic review article aims to give an overview of 15 years of clinical experience with evh , with appropriate attention for graft quality . based on a pubmed search all original papers , review articles , systematic reviews , and meta - analysis were collected . for the search several combinations of the terms endoscopic , minimal invasive , vessel , vein , conduit , harvest , and harvesting were used . reports investigating radial artery harvest , noncardiac use of vein conduits , the bridging technique , or other nonendoscopic techniques were excluded . during evh disposable or reusable systems are used to harvest approximately 35  cm of the upper leg gsv through a 3  cm incision on the medial side of the knee ( figure 1 ) . by repeating the same procedure in the other direction , the entire gsv ( 70  cm ) several systems are available , most frequently used are the disposable systems , namely , vasoview by maquet , virtuosaph by terumo , and clearglide by sorin . even though evh systems have become more user - friendly over the years , a significant personal as well as institutional learning curve persists . analysis of 1348 patients undergoing evh revealed that the average procedural time of the first 50 cases was 68 minutes , while the procedural time dropped significantly to 23 minutes in the last 200 cases . in general one can expect a personal learning curve of 20100 procedures , depending on surgical experience . based on the review of available literature , evh can be considered a save operative procedure . the few case reports describing evh specific complications relate to the use of co2 insufflation , namely , severe hypercapnia , subclinical co2 embolization ( 10.4% ) , and massive co2 embolization ( 0.22% ) [ 6 , 7 ] . an important preventive measure is reduction of the co2 insufflation pressure , most importantly not allowing the co2 pressure to surpass the central venous pressure . the most complete overview article investigating noninfectious wound healing disturbances is by athanasiou et al . . this meta - analysis included 27 studies republished between 1995 and 2002 , within total 4953 patients . analysis of 12 randomised controlled trials showed a significant reduction of noninfectious wound healing disturbances ( wound drainage , haematoma , oedema , dehiscence , necrosis , need for surgical debridement , and seroma formation ) from 13% in open vein harvest to 4% after evh . the number needed to treat in order to prevent one complication was only 2 for oedema and 13 for the other complications . diabetes , hyperlipidemia , obesity , female gender , advanced age , and peripheral vascular disease are known risk factors for wound healing disturbances after open gsv harvest [ 2 , 14 ] . research has however shown that particularly these high - risk patients benefit most from minimally invasive harvest techniques . for example , in patients with diabetes and obesity no additional risk of wound healing disturbances can be found anymore if evh is used [ 14 , 15 ] . it is assumed that evh reduces the number of donor - site infections because it causes less trauma to the surrounding tissue , preserves tissue perfusion , and is less likely to create vital tissue flaps . a meta - analysis from 2003 included all available randomised controlled trials that investigated the incidence of donor - site infections ( drainage of pus from the wound , positive wound cultures , and requirement for additional treatment surgical or antibiotic treatment ) . this meta - analysis revealed that the overall wound infection rate dropped from 13% in the open harvest group to 3% in the evh group . postoperative pain quantified using the visual analogue scale , is significantly reduced after evh compared to the traditional open harvest method [ 1720 ] . demonstrated that patients undergoing evh rate their experience of pain 2 points lower ( on a 010 scale ) throughout the whole postoperative period and label themselves pain - free days earlier than their counterparts that underwent open harvest . it is therefore not surprising that a number of studies show that patients undergoing evh are able to mobilize earlier and are also more mobile at hospital discharge and 6 weeks after surgery [ 17 , 19 , 21 ] . with the reduction of wound complications and earlier mobilisation of patients , it is likely that recovery time and therefore los is reduced . two independent studies have indeed showed reduction in los in patients undergoing evh , respectively , 31 and 34% reduction compared to traditional conduit harvest [ 21 , 22 ] . another study found a nonsignificant increase of los in the evh group . the remaining 7 available studies investigating this aspect of evh , found trends towards reduced los , without significant differences [ 17 , 18 , 2428 ] . a meta - analysis from 2004 with in total 1757 patients confirmed a reduction of los if evh is used .   in the netherlands an average disposable - system costs  400 per procedure . so a legitimate question is whether the additional costs of evh are justified by the potential benefits . a controlled trial compared the total hospital costs of 100 patients undergoing either evh or conventional harvest and found no significant differences . the reduction in costs by evh that the authors had expected , was not found because of the longer use of the operating room on the one hand and failure to reduced los on the other . in 2008 , a study became available which investigated cost - effectiveness . because data on health - related quality of life was lacking , postoperative pain and mobilisation was used as a measure of effectiveness . procedural costs were calculated based on previous publications on los , operation - time , and prices of the most expensive evh system . so it is important to note that costs of readmissions , outpatient visits related to wound problems and costs of wound treatments were not included in his model . nevertheless , evh was found to be the most cost - effective method of vein harvest . since the scare after evh is considerably smaller , it is not surprising that patients are significantly more satisfied with the cosmetic result after evh then after the traditional harvest [ 17 , 23 ] . however this difference in appreciation , measured using a visual analog scale from 010 , is mostly notable during the first postoperative period . whatever the case may be , no improvement in quality of life , measured using a short form 36 questionnaire , has been demonstrated at 2 and 4 weeks after surgery . suture repairs because of holes or torn side branches of the endoscopically harvested vein are 35 times more often necessary then after open vein harvest [ 12 , 32 ] . the presence of these macroscopic lesions make one presume that the endoscopic technique inflicts more trauma to the vessel then the conventional open harvest technique . furthermore , concerns exist with regards to thermal spread due to diathermic coagulation of side branches , detrimental effects of co2 insufflation , and formation of microscopic clots in the collapsed gsv due to the pressurized working tunnel . it has been suggested that this last concern can be dealt with by early systemic heparinization . initial studies addressing graft histology did not find differences in injury to the vascular wall and found comparable endothelial integrity after evh compared to open harvest [ 17 , 19 , 27 , 34 ] . however , in 2009 boston researchers showed evidence of injury to the saphenous vein endothelium during endoscopic harvest .    using three independent techniques ( immunohistochemistry , western blot , and multiphoton microscopy ) , they demonstrated reduced calcium mobilization , nitric oxide production , and esterase activity and reduced levels of von willebrand factor , all signs of impaired structural and functional viability of saphenous vein endothelium . the authors state that the found detrimental effects on saphenous vein endothelium may lead to decreased graft patency and worse patient outcome . only a limited number of studies are available that give insights into angiographic implication of possible histological vein injury . two randomised controlled trials were not able to show significant differences in patency rate between patient undergoing evh or ovh [ 10 , 12 ] . in both studies followup was however short , namely , 3 and 6 months . davis et al . on the other hand , compared patients who had undergone evh 3.7 years prior , to patients that had undergone open harvest 0.7 years earlier . contrast - enhanced ct showed good patency rate after evh , which did not differ from the control group with the shorter followup . studies that investigate clinical outcome after evh ( e.g. , recurrent angina , number of reinterventions , recurrent acute myocardial infarction , and survival ) are scarcely available . allen et al . conducted an rct with a fairly small number of patients ( 112 isolated cabg patients ) and found comparable 5 years event - free survival between the evh and open harvest group . if a proper power analysis was conducted remains unclear , since no description is provided . several months after the boston group published about inferior histological properties of endoscopically harvested vein an important clinical paper was published in the new england journal of medicine . conducted a secondary analysis on 3000 patients that had been included in the prevent iv trial . this phase 3 trial had investigated the effect of ex vivo treatment of saphenous vein conduits with edifoligide and had not found any beneficial effect on graft patency . in 1753 , study subjects the vein graft had been harvested endoscopically and in the remaining 1247 through open surgery . comparing the two groups revealed that patients who underwent evh had higher rates of vein graft failure at 12 to 18 months . at 3 years , evh was associated with higher death ( 7.4% versus 5.8% ) , myocardial infarction , or repeat revascularization . it is important to note that the harvest method was not randomly assigned and that details on harvest technique ( e.g. , used system , experience of the endoscopist , upper or lower leg harvest , and heparin administration ) were missing . a recent observational study compared 5825 patients of whom 34% had undergone evh . at a followup of 2.6 years no correlation between harvest method and recurrent angina , number of reinterventions , acute coronary syndrome , heart failure or survival could be found . this study was also not able to find differences in the rates of freedom from angina , readmission , need for further antianginals or overall survival . for an overview of the available clinical studies see table 1 . the aim of minimally invasive conduit harvest techniques is to reduce the morbidity and recovery time associated with the procedure , whilst preserving the quality of the conduit . a series of benefits are well founded adequately : evh results in less wound healing disturbances , less donor - site infections , less postoperative pain , earlier postoperative mobilisation , reduced length of hospital stay , and is likely to be cost - effective .   however , recent publications question whether the condition of preserved conduit quality is met . all currently available publication addressing graft quality have important shortcomings , including nonrandomised designs , nonstandardized harvest methods , small sample sizes , retrospective nature , or having only short - term followup . since evh has reached an advanced stage of implementation , and has become accepted and by patients highly appreciated by part of standard care , thorough randomised evaluation has become more difficult . nevertheless a moral obligation exists to ensure without any doubt safety and durability of the endoscopically harvested conduit , since conduit quality is likely to influence clinical outcome of cabg , the golden standard for a considerable portion of patients with multivessel coronary artery disease .   therefore randomised aim of such a trial should be to show noninferiority of evh versus open harvest . since we now have reason to suspect clinical implications of possible inferior graft quality based on the findings of lopes et al . , the only relevant endpoint is mace ( major adverse cardiac events ) . the high number of covariates influencing in the primary endpoint will demand hundreds of study subjects in each study arm . the study of lopes et al . also learned us that followup should be at least one year and that the most interesting secondary endpoint would be graft patency at one year . obviously such a study would be costly , while in this field profit margins are considerably smaller then in the pci industry . willingness of companies to invest large amount of money in such studies will probably be less . nevertheless a randomised controlled trial was initiated by a manufacturer of evh systems , namely , the option study . this study , that is , a single centre , 100 patient trial , investigating graft patency among other endpoint , one year after cabg surgery . results of this and future initiatives will be eagerly awaited , since they will determine the future of endoscopic vein harvesting .