Saphenous Vein Conduits Harvested by Endoscopic Technique Exhibit Structural and Functional Damage

Mid-term outcomes of endoscopic vein harvesting in coronary artery bypass grafting: a retrospective cohort study

OBJECTIVES

Endoscopic vein harvesting (EVH) is an alternative technique to obtain the saphenous vein for coronary artery bypass grafting (CABG) surgery. We aimed to evaluate the early and mid-term outcomes of patients with EVH in CABG.

METHODS

This cohort study included consecutive isolated CABG patients in Nanjing First Hospital from July 2020 to December 2022 using propensity score matching methods. Patients were classified to EVH group and open vein harvesting (OVH) group according to the vein harvesting methods. The primary outcome was the all-cause death, and the secondary outcomes were major adverse cardiovascular events (MACEs) including cardiovascular death, heart failure, myocardial infarction and revascularization and asymptomatic survival in the follow-up.

RESULTS

Totally 1247 patients were included in the study with 849 in OVH group and 398 in EVH group. Patients with EVH were more female, diabetes, higher body mass index, more multi-vessel and left main diseases. 308 pairs were formed after the matching. There was no significant difference in the rates of in-hospital death (EVH vs. OVH, 2.3% vs. 1.3%, P = 0.543). During the 3 years follow-up, EVH grafts were considered not inferior to OVH grafts, no differences were found in all-cause death [8.5% vs. 5.0%, hazard ratio (HR) 1.565, 95% confidence interval (CI): 0.77-3.17, P = 0.21], MACEs (8.1% vs. 7.1%, HR 1.165, 95CI: 0.51-2.69, P = 0.71) and asymptomatic survival (66.7% vs. 72.5%, HR 1.117, 95%CI: 0.65-1.92, P = 0.68).

CONCLUSIONS

EVH grafts were considered comparable to OVH grafts in patients following CABG in the 3 years follow-up.

Trimmed central venous catheters do not increase endothelial injury in an ovine model

INTRODUCTION

Central venous catheters (CVCs) are often trimmed during heart transplantation and pediatric cardiac surgery. However, the risk of endothelial injury caused by the cut tip of the CVC has not been evaluated. We hypothesized that there is no difference in the degree of endothelial injury associated with trimmed CVCs versus standard untrimmed CVCs.

METHODS

In four adult male sheep, the left external jugular vein was exposed in three segments, one designated for an untouched control group, one for the trimmed CVC group, and one for the untrimmed CVC group. Trimmed and untrimmed CVC tips were rotated circumferentially within their respective segments to abrade the lumen of the vein. The vein samples were explanted, and two representative sections from each sample were analyzed using hematoxylin and eosin (H&E) staining, as well as with immunohistochemistry against CD31, von Willebrand factor (vWF), endothelial nitric oxide synthase (eNOS), and caveolin. Higher immunohistochemical stain distributions and intensities are associated with normal health and function of the venous endothelium. Data are presented as counts with percentages or as means with standard error.

RESULTS

H&E staining revealed no evidence of endothelial injury in 6/8 (75%) samples from the untouched control group, and no injury in 4/8 (50%) samples from both the trimmed and untrimmed CVC groups (p = 0.504). In all remaining samples from each group, only mild endothelial injury was observed. Immunohistochemical analysis comparing trimmed CVCs versus untrimmed CVCs revealed no difference in the percentage of endothelial cells staining positive for CD31 (57.5% ± 7.2% vs 55.0% ± 9.2%, p = 0.982), vWF (73.8% ± 8.0% vs 62.5% ± 9.6%, p = 0.579), eNOS (66.3% ± 4.2% vs 63.8% ± 7.5%, p = 0.962), and caveolin (53.8% ± 5.0% vs 51.3% ± 4.4%, p = 0.922). There were no significant differences between the groups in the distributions of stain intensity for CD31, vWF, eNOS, and caveolin.

CONCLUSION

Trimmed CVCs do not increase endothelial injury compared to standard untrimmed CVCs.

The Role of Endothelial Cells in the Onset, Development and Modulation of Vein Graft Disease

Endothelial cells comprise the intimal layer of the vasculature, playing a crucial role in facilitating and regulating aspects such nutrient transport, vascular homeostasis, and inflammatory response. Given the importance of these cells in maintaining a healthy haemodynamic environment, dysfunction of the endothelium is central to a host of vascular diseases and is a key predictor of cardiovascular risk. Of note, endothelial dysfunction is believed to be a key driver for vein graft disease-a pathology in which vein grafts utilised in coronary artery bypass graft surgery develop intimal hyperplasia and accelerated atherosclerosis, resulting in poor long-term patency rates. Activation and denudation of the endothelium following surgical trauma and implantation of the graft encourage a host of immune, inflammatory, and cellular differentiation responses that risk driving the graft to failure. This review aims to provide an overview of the current working knowledge regarding the role of endothelial cells in the onset, development, and modulation of vein graft disease, as well as addressing current surgical and medical management approaches which aim to beneficially modulate endothelial function and improve patient outcomes.

Cost Analysis of Endoscopic Conduit Harvesting Technique Using a Non-Sealed System for Coronary Artery Bypass Surgery

Objective: Endoscopic vessel harvest (EVH) is evolving as the standard of care for coronary artery bypass grafting. However, the increase in upfront equipment-related costs has resulted in reluctance of uptake globally. We investigated the costs involving a non-sealed technique for EVH versus open vessel harvesting techniques (OVH) for both the greater saphenous vein and radial artery with a 6-month follow-up. Methods: From September 2016 to December 2018, 226 patients underwent OVH while 251 patients underwent EVH using a reusable non-sealed system and a single-use radiofrequency sealing system. Cumulative costs for OVH versus EVH were calculated as a summation of total operative and in-hospital stay costs. Costs related to harvest site complication management were also analyzed for up to 6 months. Results: Total operative costs were greater in the EVH group (Can$2,283.70 [Can$1,377.60 to $4,183.50] vs Can$1,742.40 [Can$998.50 to $3,628.10], P < 0.001). Total length of stay was significantly shorter for the EVH group (5.9 [4 to 43] days vs 6.8 [4 to 55] days, P = 0.018). Cumulative costs were comparable at the end of the hospitalization period (EVH, Can$6,534.70 [Can$2,076.50 to $33,087.70] vs OVH, Can$6,112.50 [Can$3,322.30 to $45,503.50], P = 0.06). After discharge, harvest site-related complications occurred more frequently in the OVH group (27% vs 4.4%, P < 0.001), resulting in increased use of antibiotics (2.2% vs 0.8%, P = 0.02) as well as more frequent requirement for home nursing assistance in the OVH group (5.7% vs 0.8%, P = 0.002) at 6 months of follow-up. Conclusions: Cumulative costs did not show a statistical difference between OVH and EVH, with higher intraoperative costs for EVH being offset by higher harvest site management costs in the OVH group.

Endoscopic vein harvesting

Coronary artery bypass grafting is the most common cardiac surgical procedure performed worldwide and the long saphenous vein the most common conduit for this. When performed as an open vein harvest (OVH), the incision on each leg can be up to 85cm long, making it the longest incision of any routine procedure. This confers a high degree of morbidity to the procedure. Endoscopic vein harvest (EVH) methods were popularised over two decades ago, demonstrating significant benefits over OVH in terms of leg wound complications including surgical site infections. They also appeared to hasten return to usual activities and wound healing and became popular particularly in North America. Subgroup analyses of two trials designed for other purposes created a period of uncertainty between 2009–2013 while the impact of endoscopic vein harvesting on vein graft patency and major adverse cardiac events was scrutinised. Large observational studies debunked the findings of increased mortality in the short-term, allowing practitioners and governing bodies to regain some confidence in the procedure. A well designed, adequately powered, randomised controlled trial published in 2019 also definitively demonstrated that there was no increase in death, myocardial infarction or repeat revascularisation with endoscopic vein harvest. Endoscopic vein harvest is a Class IIa indication in European Association of Cardio-Thoracic Surgery (EACTS) and a Class I indication in International Society of Minimally Invasive Cardiac Surgery (ISMICS) guidelines.

Endothelial loss during the surgical procedure in saphenous veins harvested by open and endoscopic techniques in coronary artery bypass surgery

The patency of the vein graft in coronary artery bypass grafting could be dependent on the conventional open (vsO) or endoscopic (vsE) harvesting and on the hypoxic damage of endothelial cells. We aimed to evaluate both surgical techniques according to endothelial loss that occurs in the time between harvesting and implantation. Twenty-six saphenous veins were divided into vsO (n = 16) and vsE (n = 10) group. Three samples were taken from each vein. The first sample was taken after removal, the second before implantation of the distal part, and the third before the implantation of the proximal part, and they were stained with HE, Movat, and immunohistochemically with CD31. A significant loss of endothelial cells within both groups was found at the time of implantation of the distal and the proximal part of the vein graft compared to the endothelial cells at the time of harvesting. There were no significant differences in the endothelial loss between vsE and vsO groups at the time of harvesting and at the time before the implantation of the distal part. A higher number of endothelial cells was found in vsE group compared to vsO group at the time just before the implantation of the proximal part. The comparison of the implanted portions of vsE and vsO grafts to mammary arteries revealed a significant loss of endothelial cells only in vsO graft. We conclude that, at the time of implantation, the endothelial layer of the vein graft harvested endoscopically is more preserved than of the vein graft harvested openly.

The back-approach technique of endoscopic saphenous vein harvesting in coronary artery bypass grafting

Purpose

One of the concerns during endoscopic saphenous vein harvesting (EVH) in coronary artery bypass grafting (CABG) is injury to the vein or its branches. The cutting edge of bipolar electrocautery scissors, used to divide the side branches of the saphenous vein, can cause vascular injury leading to reduced graft patency. We have developed a novel back-approach technique using a C-ring to divide the wide side branches of the saphenous vein during EVH. The aim of the study was to describe the technique and assess early outcomes of EVH using this technique. The back-approach technique is as follows: (a) insert the C-ring near the target branch, (b) push the C-ring over the proximal aspect of the target branch, (c) twist the C-ring forward to capture the target branch, and (d) cut the target branch by bipolar electrocautery.

Methods

We investigated 169 patients, including 35 women (mean age 70.1 ± 8.9 years), who underwent CABG at our hospital, using a novel EVH technique. The patients were categorized as those who underwent EVH (EVH group, n = 44) or open vein harvesting (OVH) (OVH group, n = 125). This method involves the creation of a small incision (2 cm), sufficient saphenous vein dissection near the skin incision, adequate dissection to separate the vein from the surrounding tissues, and the back-approach technique with C-ring to divide the side branch of the saphenous vein. The primary endpoint was the graft patency rate, and the secondary endpoints were leg wound complications and length of hospitalization.

Results

No significant intergroup difference was observed in early patency of saphenous vein graft patency (OVH vs. EVH = 94.7 vs. 95.6%, p = 0.763). The incidence of lower extremity wound lymphorrhea was significantly lesser (OVH: EVH = 16.0: 0.0%, p = 0.005) and the length of hospitalization was also significantly shorter in the EVH group (OVH vs. EVH = 24.2 ± 9.8 vs. 19.0 ± 5.3 days, p = 0.001).

Conclusions

EVH, using the back-approach technique, showed satisfactory short-term results; therefore, this technique performed with C-ring might be effective for vein harvesting during EVH.

Drug-eluting Vein Graft with Acetylsalicylic Acid-Ticagrelor-Unfractionated Heparin Complex Inhibits Early Graft Thrombosis

Background

Bypass graft surgery remains to be an important treatment option for left main and multivessel coronary artery disease. Approximately 2% of saphenous vein grafts are lost immediately after the coronary artery bypass graft operations and 12% in the first month due to thrombosis.

Aims

To administer one anticoagulant and two antiplatelet agents in a way that locally affects the vein graft before the bypass operation and to thereby analyse their effects on early graft thrombosis.

Study Design

Animal experimentation.

Methods

Since ticagrelor was used locally for the first time in this study, its efficacy in combination with other drugs (acetylsalicylic acid, acetylsalicylic acid and ticagrelor, and acetylsalicylic acid + ticagrelor + unfractionated heparin) was examined on rats including control (untreated) and sham (pluronic gel) group (n=14 for each group). Before the tunica adventitia layer of the femoral veins was bypassed to the femoral artery, it was coated with the drug-eluting pluronic F-127 gel. The presence or absence of thrombus in the vein graft samples was recorded under light microscopy. In vein graft preparations where thrombus was detected, the thrombus area (μm²) was calculated using the Axiovision software. Immunohistochemical staining was performed with the anti-rat von Willebrand factor polyclonal antibody kit.

Results

The number of preparations containing thrombus was significantly lower in the acetylsalicylic acid + ticagrelor + unfractionated heparin group than in the acetylsalicylic acid, control, and sham groups, according to the comparisons made on the 1^st and 3^rd days (p=0.001 and 0.02, respectively). von Willebrand factor staining was significantly lower in the acetylsalicylic acid + ticagrelor + unfractionated heparin group than in the other groups on the 3^rd day (p=0.005).

Conclusion

Locally effective acetylsalicylic acid-ticagrelor-unfractionated heparin complex has been shown to significantly reduce thrombus formation in vein grafts in this experimental model. Local administration of these drugs, which are routinely administered orally just before stent implantations, on the vein graft before the bypass is performed can prevent the loss of vein grafts due to thrombus, thereby reducing the mortality and morbidity of these patients.

The no-touch saphenous vein is an excellent alternative conduit to the radial artery 8 years after coronary artery bypass grafting: A randomized trial

BACKGROUND

In 2004, a prospective randomized trial demonstrated that after 3 years, saphenous veins (SVs) harvested with a no touch (NT) technique had a greater patency than radial grafts for coronary bypass surgery. Here we report the 8-year follow-up data of this trial.

METHODS

The trial included 108 patients undergoing coronary artery bypass grafting (CABG). Each patient was assigned to receive 1 NT SV and 1 radial artery (RA) graft to either the left or right coronary territory to complement the left internal thoracic artery (LITA). Sequential grafting was common, so overall graft patency as well as the patency of each anastomosis were assessed.

RESULTS

Angiography was performed in 84 patients (78%) at mean of 97 months postoperatively. Graft patency were high and similar for both NT and RA: 86% for NT versus 79% for RA (P = .22). The patency of coronary anastomoses was significantly higher with the NT SV grafts (91% vs 81%; P = .046). The NT grafts also had excellent patency in coronary arteries with <90% stenosis (93% patency) and in coronary arteries of small diameter (87% patency) or with mild calcification (88% patency). Patency for the LITA was 92%.

CONCLUSIONS

NT SV grafts have excellent patency similar to that of RA grafts after 8 years. In addition, NT SV grafts can be used in situations that are not ideal for RA grafts.

“No-Touch” versus “Endo” Vein Harvest: Early Patency on Symptom-Directed Catheterization and Harvest Site Complications

Objective

“No-touch” (NT) saphenous vein harvesting preserves the adventitial vasa vasorum, prevents medial ischemia, and is associated with an improved short-term and long-term vein graft patency. It may also be associated with a higher rate of harvest site complications. Endovascular vein harvesting (endo-vein) has a low rate of harvest site complications but also a tendency toward a lower patency rate.

Methods

During a 2-year period (2011–2012), we compared the vein graft patency at symptom-directed cardiac catheterization as well as wound complication rates in 210 patients who received either NT (87 patients) or endo-vein (123 patients).

Results

The recatheterization rate for the two groups was similar: 9 (10.3%) of 87 of the NT patients versus 11 (9.0%) of 123 of the endo-vein patients. There was a significant difference in vein graft patency between the groups: 15 (94%) of 16 NT vein grafts were patent versus 6 (27%) of 22 of endo-veins ( P < 0.02). The endo-vein graft patency during this 2-year period was similar to the total endo-vein patency (37%) during a 4-year period. A comparison between a more experienced and a less experienced harvester revealed no difference in patency rate. Harvest site complications were significantly higher with the NT harvest: 18% of the NT patients requiring vacuum-assisted wound closure or intravenous antibiotics versus 2% of the endo-vein patients ( P < 0.0001). The application of platelet-rich plasma did not significantly lower wound complication rates ( P = 0.27).

Conclusions

These results suggest that NT vein harvesting may be associated with improved graft patency, but methods should be developed to lower wound complication rates.

State-of-the-Art Coronary Artery Bypass Grafting: Patient Selection, Graft Selection, and Optimizing Outcomes

Despite the progressive expansion of clinical indications for percutaneous coronary intervention and the increasingly high risk profile of referred patients, coronary artery bypass grafting (CABG) remains the mainstay in multivessel disease, providing good long-term outcomes with low complication rates. Multiple arterial grafting, especially if associated with anaortic techniques, might provide the best longer-term outcomes. A surgical approach individualized to the patients' clinical and anatomic characteristics, and surgeon and team experience, are key to excellent outcomes. Current evidence regarding patient selection, indications, graft selection, and potential strategies to optimize outcomes in patients treated with CABG is summarized.

Graft patency after open versus endoscopic saphenous vein harvest in coronary artery bypass grafting surgery: a systematic review and meta-analysis

Background

Saphenous vein grafts (SVG) are a commonly used conduit for coronary artery bypass graft (CABG) surgery and can be harvested by either an open or endoscopic technique. Our goal was to evaluate long-term angiographic and clinical outcomes of open compared to endoscopic SVG harvest for CABG.

Methods

Electronic search was performed to identify all studies in the English literature that compared open and endoscopic SVG harvesting for CABG with at least one year of follow-up. The primary outcome was graft patency. Secondary outcomes included perioperative morbidity and mortality.

Results

Of 3,255 articles identified, a total of 11 studies were included for analysis. Of 18,131 patients, 10,873 (60%) patients underwent open SVG harvest and 7,258 (40%) patients underwent endoscopic SVG harvest. The mean age of patients was 65 years and 87% were male. The overall mean follow-up period was 2.6 years. During follow-up, patients who underwent open SVG harvest had superior graft patency per graft [open 82.3% vs. endoscopic 75.1%; OR: 0.61 (95% CI, 0.43-0.87); P=0.01], but higher rates of overall wound complications in the immediate post-operative period [open 3.3% vs. endoscopic 1.1%; OR: 0.02 (95% CI, 0.01-0.06); P<0.001]. Patients who underwent open SVG harvest had higher postoperative 30-day mortality [open 3.4% vs. endoscopic 2.1%; OR: 0.59 (95% CI, 0.37-0.94); P=0.03], but no significant difference in overall mortality [open 4.9% vs. endoscopic 4.9%; OR: 0.34 (95% CI, 0.50-1.27); P=0.34].

Conclusions

Patients who underwent an open SVG harvest technique had improved graft patency and comparable overall mortality to endoscopic SVG harvest at average follow-up time of 2.6 years. Patients with open SVG harvest had higher rates of early wound complications and postoperative 30-day mortality, however, there was no difference in overall mortality.

P2X7R antagonism after subfailure overstretch injury of blood vessels reverses vasomotor dysfunction and prevents apoptosis

Human saphenous vein (HSV) is harvested and prepared prior to implantation as an arterial bypass graft. Injury and the response to injury from surgical harvest and preparation trigger cascades of molecular events and contribute to graft remodeling and intimal hyperplasia. Apoptosis is an early response after implantation that contributes the development of neointimal lesions. Here, we showed that surgical harvest and preparation of HSV leads to vasomotor dysfunction, increased apoptosis and downregulation of the phosphorylation of the anti-apoptotic protein, Niban. A model of subfailure overstretch injury in rat aorta (RA) was used to demonstrate impaired vasomotor function, increased extracellular ATP (eATP) release, and increased apoptosis following pathological vascular injury. The subfailure overstretch injury was associated with activation of p38 MAPK stress pathway and decreases in the phosphorylation of the anti-apoptotic protein Niban. Treatment of RA after overstretch injury with antagonists to purinergic P2X7 receptor (P2X7R) antagonists or P2X7R/pannexin (PanX1) complex, but not PanX1 alone, restored vasomotor function. Inhibitors to P2X7R and PanX1 reduced stretch-induced eATP release. P2X7R/PanX1 antagonism led to decrease in p38 MAPK phosphorylation, restoration of Niban phosphorylation and increases in the phosphorylation of the anti-apoptotic protein Akt in RA and reduced TNFα-stimulated caspase 3/7 activity in cultured rat vascular smooth muscle cells. In conclusion, inhibition of P2X7R after overstretch injury restored vasomotor function and inhibited apoptosis. Treatment with P2X7R/PanX1 complex inhibitors after harvest and preparation injury of blood vessels used for bypass conduits may prevent the subsequent response to injury that lead to apoptosis and represents a novel therapeutic approach to prevent graft failure.

Complications of CO2 insufflation during endoscopic vein harvesting

Over the past few decades, the use of endoscopic harvest of the saphenous vein has gained popularity due to a significant reduction in rates of wound infection and improved cosmesis. The widespread adoption of this technique has introduced a set of complications associated with the use CO₂ insufflation which facilitates exposure during the vein harvest. We describe a case of pneumoperitoneum with systemic acidosis and subcutaneous air following endoscopic vein harvest for coronary artery bypass grafting and review the complications that may arise from CO₂ insufflation during endoscopic vein harvesting.

Randomized Study Comparing the Effect of Carbon Dioxide Insufflation on Veins Using 2 Types of Endoscopic and Open Vein Harvesting

OBJECTIVE

The aim of the study was to assess whether the use of carbon dioxide insufflation has any impact on integrity of long saphenous vein comparing 2 types of endoscopic vein harvesting and traditional open vein harvesting.

METHODS

A total of 301 patients were prospectively randomized into 3 groups. Group 1 control arm of open vein harvesting (n = 101), group 2 closed tunnel (carbon dioxide) endoscopic vein harvesting (n = 100) and Group 3 open tunnel (carbon dioxide) endoscopic vein harvesting (open tunnel endoscopic vein harvesting) (n = 100). Each group was assessed to determine the systemic level of partial arterial carbon dioxide, end-tidal carbon dioxide, and pH. Three blood samples were obtained at baseline, 10 minutes after start of endoscopic vein harvesting, and 10 minutes after the vein was retrieved. Vein samples were taken immediately after vein harvesting without further surgical handling to measure the histological level of endothelial damage. A modified validated endothelial scoring system was used to compare the extent of endothelial stretching and detachment.

RESULTS

The level of end-tidal carbon dioxide was maintained in the open tunnel endoscopic vein harvesting and open vein harvesting groups but increased significantly in the closed tunnel endoscopic vein harvesting group (P = 0.451, P = 0.385, and P < 0.001). Interestingly, partial arterial carbon dioxide also did not differ over time in the open tunnel endoscopic vein harvesting group (P = 0.241), whereas partial arterial carbon dioxide reduced significantly over time in the open vein harvesting group (P = 0.001). A profound increase in partial arterial carbon dioxide was observed in the closed tunnel endoscopic vein harvesting group (P < 0.001). Consistent with these patterns, only the closed tunnel endoscopic vein harvesting group demonstrated a sudden drop in pH over time (P < 0.001), whereas pH remained stable for both open tunnel endoscopic vein harvesting and open vein harvesting groups (P = 0.105 and P = 0.869, respectively). Endothelial integrity was better preserved in the open vein harvesting group compared with open tunnel endoscopic vein harvesting or closed tunnel endoscopic vein harvesting groups (P = 0.012) and was not affected by changes in carbon dioxide or low pH. Significantly greater stretching of the endothelium was observed in the open tunnel endoscopic open tunnel endoscopic vein harvesting group compared with the other groups (P = 0.003).

CONCLUSIONS

This study demonstrated that the different vein harvesting techniques impact on endothelial integrity; however, this does not seem to be related to the increase in systemic absorption of carbon dioxide or to the pressurized endoscopic tunnel. The open tunnel endoscopic harvesting technique vein had more endothelial stretching compared with the closed tunnel endoscopic technique; this may be due to manual dissection of the vein. Further research is required to evaluate the long-term clinical outcome of these vein grafts.

Endothelial Function Is Preserved in Veins Harvested by Either Endoscopic or Surgical Techniques

BACKGROUND

Endoscopic vein harvest for lower extremity arterial bypass grafting has been questioned due to concern for endothelial damage during procurement. We sought to compare nitric oxide (NO)-mediated endothelial-dependent relaxation (EDR) in vein segments harvested using open surgical techniques (OH) versus endoscopic vein harvest (EH) techniques.

METHODS

Saphenous vein segments were harvested for lower extremity bypass, and a single, minimally handled section of saphenous vein, free of branches, was taken from the end of the graft. Four 4-mm venous ring segments were then cut and mounted on force transducers. Segments were mounted in 37° oxygenated Krebs-Henseleit solution and maximally contracted using KCl. Individual ring segments that did not react to KCl were excluded from the study. Norepinephrine (NE) was used to achieve submaximal contraction. EDR was determined using increasing concentrations of bradykinin (BDK). Endothelial-independent relaxation (EIR) was confirmed using sodium nitroprusside. Two-way analysis of variance (ANOVA) was used to analyze differences between harvest techniques across BDK concentration and a Student's t-test was used to analyze single comparisons.

RESULTS

Vein segments harvested from patients (n = 13) led to 28 viable rings that exhibited a positive reaction to KCl (11 rings; 5 patients EH vs. 17 rings; 8 patients OH). Both vein groups achieved moderate relaxation to maximal BDK concentration, [10^-6 M]; (49.5% EH vs. 40.55% OH, P = 0.270). Analysis by 2-way ANOVA for mean % relaxation for BDK concentration [10^-11-10^-6 M] showed improved EDR in EH samples compared with OH (P = 0.029). Mean nitrite/nitrate (NO_(x)) tissue bath concentration measurements post-BDK were 139.8 nM (EH) vs. 97.2 nM (OH; P = 0.264). Histology and positive factor VIII immunohistochemistry staining provided evidence for the presence of intact endothelium in our sample segments. EIR was preserved and was similar in the two groups.

CONCLUSIONS

Endothelial function is preserved when utilizing endoscopic harvesting techniques. The advantages of minimally invasive vein procurement for lower extremity bypass can be obtained without concern for damaging venous endothelium.

Subfailure Overstretch Injury Leads to Reversible Functional Impairment and Purinergic P2X7 Receptor Activation in Intact Vascular Tissue

Vascular stretch injury is associated with blunt trauma, vascular surgical procedures, and harvest of human saphenous vein for use in vascular bypass grafting. A model of subfailure overstretch in rat abdominal aorta was developed to characterize surgical vascular stretch injury. Longitudinal stretch of rat aorta was characterized ex vivo. Stretch to the haptic endpoint, where the tissues would no longer lengthen, occurred at twice the resting length. The stress produced at this length was greater than physiologic mechanical forces but well below the level of mechanical disruption. Functional responses were determined in a muscle bath, and this subfailure overstretch injury led to impaired smooth muscle function that was partially reversed by treatment with purinergic receptor (P2X7R) antagonists. These data suggest that vasomotor dysfunction caused by subfailure overstretch injury may be due to the activation of P2X7R. These studies have implications for our understanding of mechanical stretch injury of blood vessels and offer novel therapeutic opportunities.

Comparative results of endoscopic and open methods of vein harvesting for coronary artery bypass grafting: a prospective randomized parallel-group trial

Background

We compared wound complications between endoscopic and open great saphenous vein harvesting for coronary artery bypass surgery.

Methods

A total of 228 consecutive patients were prospectively randomized into two groups: open vein harvesting (OVH), 115 patients; and endoscopic vein harvesting (EVH), 113 patients. Each group was assessed for post-operative wound complications, pain intensity, and neuropathy in the early post-surgical period. Lymphoscintigraphy of the lower limbs as well as morphological studies of vein walls using light and electron scanning microscopy were performed.

Results

Vein harvesting time was shorter for EVH than OVH: 31.8 ± 6.2 min and 40.3 ± 15.8 min, respectively (p < 0.01). There were fewer complications after vein harvesting in the EVH group (11.5 %) than in the OVH group (44.4 %) (р = 0.001). Multivariate analysis showed that diabetes mellitus was the only risk factor for post-surgical complications after OVH (odds ratio = 3.95 %; 95 % confidence interval 1.03–8.6). Lymphoscintigraphic data in the EVH group did not demonstrate considerable disturbances in lymph drainage after surgery. In the OVH group, the accumulation of radiopharmaceutical drugs in the lymphatic nodes reduced two-fold (р ≤ 0.001). Histological evaluation of vein samples did not show considerable damage to the vein wall in either group.

Conclusions

Using electron microscopy of vein fragments, this study demonstrated that EVH reduces wound complications and provides good-quality conduits.

Endoscopic Versus “No-Touch” Saphenous Vein Harvesting for Coronary Artery Bypass Grafting

The advantage in terms of wound infection, wound healing, and scarring has resulted in the recent adoption of endoscopic vein harvesting (EVH) as a standard of care for coronary artery bypass grafting in some centers. However, concerns regarding the quality of these grafts have been raised after recent evidence of decreased graft patency, increased reoperation rate, and myocardial infarct, problems that are associated with vascular trauma caused when using this technique. Simultaneously, an atraumatic, “no-touch” technique for harvesting the saphenous vein was developed producing grafts with improved patency comparable to the internal thoracic artery. However, wound complications remain a problem using this technique. This review outlines the need to consider the poor graft quality that may result from EVH and raises the question what is likely to be the “best practice principle” in saphenous vein harvesting?

Endoscopic harvesting device type and outcomes in patients undergoing coronary artery bypass surgery

OBJECTIVE

To evaluate angiographic and clinical outcomes associated with open and closed dissection tunnel endoscopic vein harvesting (EVH) devices.

BACKGROUND

A previous PREVENT-IV (PRoject of Ex-vivo Vein graft ENgineering via Transfection IV) analysis reported that EVH for coronary artery bypass graft surgery was associated with worse outcomes than with traditional vein harvesting; however, outcomes by EVH device type were not available.

METHODS

Using data from the PREVENT-IV trial, we compared 1549 patients from 75 surgical sites who underwent EVH with open (n = 390) or closed (n = 1159) harvest tunnel devices. Outcomes included the incidence of vein graft failure at 12 to 18 months and a composite of death, myocardial infarction, and revascularization through 5 years.

RESULTS

Among patients undergoing open and closed tunnel EVH, no difference in the per-patient incidence of vein graft failure (43.8% vs 47.1%; adjusted odds ratio, 0.91; 95% confidence interval, 0.53-1.55; P = 0.724) or per-graft incidence of vein graft failure (25.5% vs 25.9%; adjusted odds ratio, 0.96; 95% confidence interval, 0.59-1.55; P = 0.847) was observed. At 5 years, no difference was observed in the primary composite clinical outcome between patients who underwent open and closed system EVH (21.5% vs 23.9%; adjusted hazard ratio, 0.85; 95% confidence interval, 0.66-1.10; P = 0.221).

CONCLUSIONS

No differences in angiographic or clinical outcomes were observed among patients who underwent open versus closed tunnel endoscopic harvesting for coronary bypass surgery. These findings suggest that the risks associated with EVH that were reported in a previous PREVENT-IV analysis are not related to a specific EVH device.

Vein harvesting technique for infrainguinal arterial bypass with great saphenous vein and its association with surgical site infection and graft patency

OBJECTIVE

The objective of this study was to investigate the association of vein harvesting technique (VHT) with surgical site infection (SSI) and graft patency after infrainguinal arterial bypass.

METHODS

The Vascular Quality Initiative database was used to review VHT of all patients undergoing single-segment great saphenous vein graft infrainguinal arterial bypass from 2003 to 2013. Patients were divided into three groups according to the VHT used (continuous incision, skip incision, and endoscopic). Multinomial logistic regression was performed to estimate propensity scores for each treatment group. Propensity score adjustment was included in multivariable analysis of the primary outcomes: SSI and graft primary patency.

RESULTS

From 2003 to 2013, 5066 patients underwent single-segment great saphenous vein graft infrainguinal bypass. The VHT was continuous incision in 48.6%, skip incision in 39.7%, and endoscopic in 12.7%. SSI rates did not differ significantly among the groups (continuous, 4.7%; skip, 4.0%; endoscopic, 3.4%; P = .278). On multivariable analysis, there was no difference in discharge primary patency between the three groups. At 1 year, primary patency rates were 69.5% for continuous, 73.0% for skip, and 58.6% for endoscopic (P < .001). After multivariable analysis, endoscopic vein harvest was independently associated with higher 1-year primary patency loss compared with both continuous (hazard ratio [HR], 1.35; 95% confidence interval [CI], 1.05-1.74; P = .020) and skip (HR, 1.53; 95% CI, 1.18-2.00; P = .002). There was no significant difference in 1-year primary patency loss between continuous and skip techniques (HR, 0.88; 95% CI, 0.73-1.05; P = .170).

CONCLUSIONS

No association between the choice of VHT and the development of SSI after infrainguinal arterial bypass was identified in the Vascular Quality Initiative population. Endoscopic VHT was associated with significantly reduced 1-year primary patency rate compared with both continuous and skip techniques.

Immunohistochemistry comparing endoscopic vein harvesting vs. open vein harvesting on saphenous vein endothelium

Objective

The present study attempts to compare the immunohistochemistry (IHC) of von Willebrand factor (vWf) , endothelial cadherin, Caveolin and endothelial Nitric Oxide Synthase (eNOS) in VasoView Endoscopic Vein Harvesting (EVH) versus traditional Open Vein Harvesting (OVH) techniques for Coronary Artery Bypass Graft (CABG) Surgery performed in Javad al Aemeh Hospital of Mashhad, Iran in 2013,.

Methods and materials

Forty-seven patients were scheduled for CABG (30 EVH and 17 OVH) among whom patients with relatively same gender and similar age were selected. Three separate two cm vein samples were harvested from each patient’s saphenous vein. Each portion was collected from distal, middle and proximal zones of the saphenous vein. The tissues were deparaffinized, and antigen retrieval was done using EZ-retriever followed by an immunohistochemistry evaluation with vWf, e-cadherin, Caveolin and eNOS. In addition, demographic questioner as of Lipid profile, FBS, BMI, and cardiovascular risk factors were collected. Data analyses, including parametric and nonparametric tests were undertaken using the SPSS 16 software. A P value < 0.05 was regarded as statistically significant.

Results

The mean age of the EVH and OVH groups were 63.76 ± 9.51 and 63.63 ± 8.31 years respectively with no significant difference between them (p = 0.989). In addition, there was no great difference between the EVH and OVH groups in lipid profile, DM, HTN, smoking history, CVA, and valvular dysfunction (P > 0.05). Qualitative report of vWf, e-cadherin, Caveolin and eNOS reveals no significant difference between the EVH and OVH (P > 0.05).

Conclusion

This study indicates that VasoView EVH technique causes no endothelial damage in comparison with OVH. This study could be a molecular confirmation for the innocuous of EVH technique.

Choice of vein-harvest technique for coronary artery bypass grafting: rationale and design of the REGROUP trial

The Randomized Endo-vein Graft Prospective (REGROUP) trial (ClinicalTrials.gov NCT01850082) is a randomized, intent-to-treat, 2-arm, parallel-design, multicenter study funded by the Cooperative Studies Program (CSP No. 588) of the US Department of Veterans Affairs. Cardiac surgeons at 16 Veterans Affairs (VA) medical centers with technical expertise in performing both endoscopic vein harvesting (EVH) and open vein harvesting (OVH) were recruited as the REGROUP surgeon participants. Subjects requiring elective or urgent coronary artery bypass grafting using cardiopulmonary bypass with use of ≥1 saphenous vein graft will be screened for enrollment using pre-established inclusion/exclusion criteria. Enrolled subjects (planned N = 1150) will be randomized to 1 of the 2 arms (EVH or OVH) after an experienced vein harvester has been assigned. The primary outcomes measure is the rate of major adverse cardiac events (MACE), including death, myocardial infarction, or revascularization. Subject assessments will be performed at multiple times, including at baseline, intraoperatively, postoperatively, and at discharge (or 30 days after surgery, if still hospitalized). Assessment of leg-wound complications will be completed at 6 weeks after surgery. Telephone follow-ups will occur at 3-month intervals after surgery until the participating sites are decommissioned after the trial's completion (approximately 4.5 years after the full study startup). To assess long-term outcomes, centralized follow-up of MACE for 2 additional years will be centrally performed using VA and non-VA clinical and administrative databases. The primary MACE outcome will be compared between the 2 arms, EVH and OVH, at the end of the trial duration.

Endoscopic versus open saphenous vein graft harvest for lower extremity bypass in critical limb ischemia

OBJECTIVE

Endoscopic vein harvest (EVH) has been demonstrated to improve early morbidity when compared with conventional open vein harvest (OVH) technique for infrainguinal bypass surgery. However, recent literature suggests conflicting results regarding mid- and long-term patency with EVH. The purpose of this study is to compare graft patency between harvest techniques specifically in patients with critical limb ischemia.

METHODS

This retrospective study compared two groups of patients (EVH = 39 and OVH = 49) undergoing lower extremity revascularization from January 2009 to December 2011. Outcome measures included patency rates, postoperative complications, and wound infection. Graft patency was assessed using Kaplan-Meier curves.

RESULTS

Both groups were matched for demographics and indications for bypass (critical limb ischemia). Median follow-up was 22 months. There was a significant reduction in the incidence of wound infection at the vein harvest site in the EVH group (OVH = 20%; EVH = 0%; P < .001), nevertheless, the difference was not significant when only the anastomotic sites were included (OVH = 12.2%; EVH = 15.4%; P = .43). The hospital length of stay was comparable between the two groups (EVH = 8.73 ± 9.69; OVH = 6.35 ± 3.28; P = .26) with no significant difference in the recovery time. Primary graft patency rate was 43.2% in the EVH group and 69.4% in the OVH group (P = .007) at 3 years. The most common reason for loss of primary patency was graft occlusion (61.5%) in the OVH group and vein graft stenosis (54.5%) in the EVH group. The average number of vascular reinterventions per bypass graft was significantly lower in the OVH group compared with the EVH group (OVH = 0.37; EVH = 1.28; P < .001).

CONCLUSIONS

Our findings demonstrate inferior primary patency when using the technique of EVH. Additionally, we identified a significantly higher rate of reintervention in the EVH cohort as well as a higher rate of vein graft body stenosis. However, EVH was associated with a decreased rate of wound complications with similar limb salvage and secondary patency rates when compared to OVH. EVH should therefore be selectively utilized in patients at high risk for wound complications.