Synergizing Antegrade Endoscopic with Bridging Vein Harvesting for Improvement of Great Saphenous Vein Graft Quality from the Lower Leg

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Summary

Presented here is a protocol for antegrade endoscopic vein harvesting from the lower leg, which can safely be introduced in routine coronary artery bypass grafting. Vein grafts present excellent graft quality following this standardized protocol with positioning of the legs, minimally invasive access to the vein, and antegrade endoscopic vein harvesting.

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Klopsch, C., Kaminski, A., Prall, F., Dohmen, P. Synergizing Antegrade Endoscopic with Bridging Vein Harvesting for Improvement of Great Saphenous Vein Graft Quality from the Lower Leg. J. Vis. Exp. (153), e59009, doi:10.3791/59009 (2019).

Abstract

Antegrade endoscopic harvesting of autografts for bypass grafting may be an optimal strategy addressing excellent graft quality and reduced post-operative wound complications. This standardized protocol for antegrade endoscopic vein harvesting (EVH) from the lower leg has the potential to be introduced to routine coronary artery bypass grafting (CABG). Patients undergoing CABG surgery are positioned on a surgical table with two additional foam rollers below the extended legs, enabling antegrade EVH from the lower leg. Following minimally invasive surgical access through a bridging vein harvest technique, an endoscopic optical dissector is inserted antegrade into the wound. The main vessel and side branches are dissected under continuous optical control of vein quality status and the working channel. After, an endoscopic optical retractor is inserted with an internal bipolar electrocoagulation device for precise, safe, and tissue-protective interruption of side branches. After release of the vein, the vessel is cut off at the proximal and distal ends under optical control, retrieved from the wound, then cannulated and flushed with heparinized saline. Finally, all side branches of the vein graft are double-clipped. Vascular histology is analyzed in a randomized selection of vein samples. After applying this standardized EVH protocol, the learning curve was shown to be steep, and graft quality was sufficient for coronary artery bypass grafting in every case. There was no conversion to surgical harvesting and low risks for tissue damage and bleeding. Leg positioning and synergizing EVH with bridging vein harvesting improved procedural success and vein graft quality. In our hands, antegrade EVH from the lower leg was feasible, demonstrating straightforward graft dissection as well as adequate macroscopic and microscopic graft quality with preserved endothelial integrity. In conclusion, the introduced technique is safe, shows excellent vein autograft quality, and illustrates feasibility for elective and urgent isolated CABG and combined CABG scenarios.

Introduction

Open atraumatic "low-touch" and "no-touch" techniques have been developed over the years for harvesting saphenous veins in coronary artery bypass graft (CABG) surgery or peripheral bypass grafting, producing grafts with excellent endothelial integrity and long-term patency. However, wound complications remain a major problem when using the open technique, especially in obese, diabetic, and chronic venous insufficiency patients1,2,3,4. The question arises of how physicians can harvest the saphenous vein with optimal graft quality and reduced risk for wound complications. Endoscopic vein harvesting (EVH) techniques have been proven to be cost-effective, and clinical outcome parameters are comparable with the open technique. However, strategies protecting endothelial integrity, histological structure, and physiological function of vein grafts during EVH are highly appreciated in order to preserve optimal graft quality2. Recent studies have presented superior graft patency after open harvesting compared to endoscopic techniques5. It has also been shown that bridging vein harvest techniques can directly improve vein quality6. Therefore, it is hypothesized that vein graft harvesting may be advanced through synergizing antegrade EVH with minimally invasive bridging vein harvesting, specific leg positioning, and vein isolation in a tensionless working channel.

To date, conventional EVH techniques for harvesting great saphenous veins have used antegrade approaches for the upper leg and retrograde approaches for the lower leg. However, we have experienced limitations of these techniques and hold concerns about graft quality. The great saphenous vein from the knee and upper leg frequently have revealed numerous side branches and occasionally shown dilated vessel diameter, leading to impaired vessel quality and mismatching of conduit and target vessels that can negatively affect long-term graft patency after CABG and re-revascularization rate7,8,9,10,11. In our experience, the retrograde EVH approach for the lower leg has repetitively resulted in prolonged blood stasis inside the vessel (with augmented intravenous blood pressure due to closed venous valves), increased mechanical stress on the tissue, bleeding, thrombus formations, graft damage, and impaired graft quality. Consequently, this standardized protocol was developed for safe antegrade EVH from the lower leg, combining the bridging vein harvest technique for minimally invasive access site with antegrade EVH in a tensionless working channel for adequate vein graft quality.

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Protocol

The study conforms to the Declaration of Helsinki. The protocol follows the guidelines of an independent institutional ethics committee, and human biomaterials were obtained after informed written consent (ethics committee approval: A 2018-0037).

1. Positioning of the legs

NOTE: Patient inclusion criteria included a history of coronary artery disease with elective/urgent indication for CABG surgery and the need for harvesting of at least one venous bypass graft for complete revascularization. Patients with debilitating chronic disease, emergency operations, status post-deep vein thrombosis, and active wet gangrene were excluded. Pre- and post-operative procedures were comparable with previously described clinical studies12,13. 28 patients undergoing CABG were included for antegrade endoscopic vessel harvesting of 30 great saphenous veins from the lower leg after informed written consent. A cardiac surgeon certified and experienced with the technique (>200 cases) for the upper leg executed the antegrade EVH of the great saphenous veins from the lower leg.

  1. Organization of the surgical theatre
    1. Before surgery, ensure supine position of the anesthetized patient on the surgical table following institutional standard procedures for CABG surgery.
    2. Place the vein harvester on the right side of the patient. Place the surgical team and instrumental set-up for cardiac surgery on the left side of the patient. Place the instrumental set-up for EVH near the end of the table (Figure 1, Figure 2; see Table of Materials).
  2. Specific positioning of the legs
    1. Place two foam rollers (length: 60 cm, diameter: 12 cm) below the extended legs. Place one half-cylindrical foam roller just above the knee in order to avoid overstretched knees and common peroneal nerve lesions. Then, place another full cylindrical foam roller below the Achilles tendon for lifted and outward rotated foot position (Figure 1A-D).

2. Minimally invasive surgical access to the vein graft

  1. Access site
    1. Use institutional standard disinfection procedures with Octenidindihydrochlorid followed by standard sterile covering for aseptic surgical conditions.
    2. Make one longitudinal skin incision (length: 1.5-2 cm) with a curved scalpel (size 10) on the lower leg. Start the incision with the distance of approximately one index finger above the imagined ankle joint and proceed upwards parallel to the medial margin of the tibia bone (Figure 2C).
  2. Bridging vein harvesting technique
    1. Obtain minimally invasive access to the great saphenous vein with surgical forceps, dissecting surgical scissors, and an electrosurgical pencil, if necessary. Starting from the skin incision, isolate the vessel 4 cm in each direction using a vessel loop, dissecting scissors, small soft tissue retractor, and Langenbeck hook, applying the standard bridging vein harvesting technique (Figure 2C).
    2. Continuously check vein quality status and surrounding subcutaneous tissue in the working channel. Visualize in order to avoid injury to the saphenous nerve. Avoid harvesting of progressive varicose veins.
  3. Practical hints
    1. Make sure that one small finger can easily access the working channel (antegrade). Avoid surgical clipping of side branches at this time.

3. Antegrade EVH with the optical dissector

  1. Insertion of optical dissector
    1. Assemble the optical dissector by connecting an extended length endoscope (diameter: 7 mm, length: 48 cm) to an optical camera and dissection tip from the endoscopic vessel harvesting system, according to the manufacturer's instructions. Moisturize the optical dissector with saline containing heparin (i.e., NaCl + Hep: 5.000 per 200 mL).
    2. Put the inflatable blocker balloon (also provided by the endoscopic vessel harvesting system and moisturized with NaCl + Hep) over the optical dissector. Gently insert the optical dissector (antegrade) and, after, the inflatable blocker balloon into the wound under permanent optical control of the vein (Figure 2D-F).
  2. Dissection of the vein
    1. Block the inflatable blocker balloon with room air (10 mL). Flood the working channel with CO2 (flow: 5 L/min, pressure: 15 cm H2O) and indicate to the anesthetic medical staff. Make sure that the working channel is extended by the gas pressure.
    2. Move antegrade until reaching the imagined proximal medial end of tibial diaphysis using the optical dissector, following the manufacturer´s instructions. Gently dissect the main vessel from a majority of subcutaneous tissue until achieving clear identification of side branches.
    3. For optimal results, dissect the main vessel through antegrade movement of the optical dissector 1) above of, then 2) below, the main vessel. Then, selectively dissect the side branches, with one side of the vein preserving the perivascular tissue as far as possible, followed by the other side (Figure 2G-I).
    4. Continuously check vein quality status and mechanical stress in the working channel. Visualize in order to avoid injury to the saphenous nerve. Avoid harvesting of progressive varicose veins.

4. Antegrade EVH with the optical retractor

  1. Insertion of optical retractor
    1. Remove the optical dissector from the wound and disconnect the dissection tip.
    2. Adapt the blocker balloon for the optical retractor and block the working channel with a 5 mL syringe. Assemble the optical retractor by connecting the extended length endoscope to the optical camera and retractor device from the endoscopic vessel harvesting system, which is provided with an internal bipolar electrocoagulation device (power output: level 3-4).
    3. Use anti-fog fluid for the tip of the endoscope (Figure 3A-C). Again, moisturize the optical retractor with NaCl + Hep before antegrade insertion through the blocked balloon.
  2. Isolation of the vein
    1. Advance the optical retractor antegrade to the end of the working channel. Release the vein from the surrounding subcutaneous tissue with the retractor device and selectively interrupt side branches with the bipolar electrocoagulation device in a retrograde fashion (Figure 3D-F). Here, the bipolar electrocoagulation device must be positioned with the convex ending away from the main vessel.
    2. Continuously check vein quality status and mechanical stress in the working channel. Visualize in order to avoid injury to the saphenous nerve.

5. Vein graft retrieval

  1. Finishing of EVH
    1. Execute a stab incision in the skin with a sharp scalpel (size 11) at the distal end of the dissected vein (regarding venous flow direction). Insert a smooth (anatomical) clamp through the stab incision and clamp the vein under optical control with the optical retractor.
    2. Gently retrieve the clamped vein through the stab incision and cut it off proximally (regarding venous flow direction). Thereafter, gently remove the optical retractor through the blocked balloon simultaneously relieving the distal portion of the vein (Figure 3G). Deflate the blocker balloon and remove it from the wound.
    3. Switch off CO2 and indicate it to the anesthetic medical staff. At this time, use surgical clips and interrupt the remaining side branches before retrieval of the vein graft, if necessary.
  2. Finishing of bridging vein harvesting
    1. Execute a stab incision in the skin with a sharp scalpel (size 11) at the proximal end of the isolated vein approximately 3 cm above imagined ankle joint. Insert an anatomical clamp through the stab incision and retrieve the vein though the skin incision under digital and optical control. Visualize and avoid injury to the saphenous nerve.
    2. Then, clamp the vein under direct vision and cut off distally (regarding venous flow direction). Thereafter, gently relieve the entire vein graft through the initial minimally-invasive surgical access site and cannulate the proximal end with a 3.0 mm flexible vessel cannula (Figure 3H).

6. Final preparation of the vein graft

  1. Gently flush the released venous graft with NaCl + Hep (in a 10 mL syringe) alternating with double-clipping of all side branches (Figure 3H). Continuously check vein quality status and repair injuries, if necessary, with polypropylene sutures (7-0 or 8-0). Finally, the vein harvester and primary surgeon must evaluate graft quality of the endoscopic vein, applying the same criteria as is executed for veins harvested by the open technique.
  2. If necessary, store the vein graft in a NaCl + Hep-moisturized compress at room temperature (RT) for short-term storage. However, avoid longer time periods of storage. Transfer the vein graft into heparinized blood as soon as arterial cannulation for cardiopulmonary bypass is accomplished.

7. Wound closure

  1. Ligate the main vessel at both clamped vein ends, each with a 4-0 polyglactin 910 suture. Remove the clamps.
  2. Insert a 10Fr Redon drain into the wound (Figure 3I). Fixate the Redon drain with 2-0 poly ethylene terephthalate suture at the skin.
  3. Execute subcutaneous and intracutaneous wound closures at the minimally invasive access site with 2-0 and 4-0 polyglactin 910 sutures, respectively. Close the two small stab incisions at the proximal and distal ends, with one U-suture each, stitched intracutaneously (4-0 polyglactin 910). Drape the wounds with sterile plasters.
  4. Wrap the leg, except in peripheral artery disease patients.

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Representative Results

A steep learning curve was demonstrated for an experienced cardiac surgeon performing antegrade EVH of the great saphenous vein from the lower leg (Figure 4). There were no conversions to surgical harvesting. However, there were four cases of vein injury in the beginning of the learning curve. In three of the four cases, major injuries occurred at the distal portion of the vein because of an inadequately narrow working channel when the surgeon isolated the vein above the tibial metaphysis. Disruption of a major side branch in two cases and dilaceration of the distal vein in one case were observed, leading to discarding of the distal portion of the vein. The remaining vein grafts were adequate for CABG in every case. In one of the four cases, minor injury was observed at two small side branches at the proximal portion of the vein, when surgical clipping of side branches was executed in the working channel before antegrade EVH. These injuries were repaired with polypropylene sutures. Final vein graft quality was macroscopically sufficient for CABG in every case regarding graft length, graft diameter, absence of injury, and vessel wall integrity.

In three randomly selected patients, antegrade EVH (as explained above) was extended by additional open vein harvesting from imagined tibial metaphysis upwards to the distal third of the upper leg. Vein samples (about 3 mm in diameter) used for these studies were taken from excess material near the ankle joint (bridging vein harvesting technique), imagined tibial metaphysis (open harvesting technique), and proximal medial end of the imagined tibial diaphysis (antegrade EVH technique). The samples were blinded to the participating pathologist, fixed in formalin, sectioned transversely, and embedded in paraffin by routine procedures. Hematoxylin and eosin-stained 5 µm sections were prepared for light microscopy, and CD31 immunostains were obtained to demonstrate further that endothelial cells and integrity remained intact.

These randomized blind microscopic analyses revealed an intact vascular morphology (Figure 5A,B) and completely preserved endothelial integrity (Figure 5C) in all analyzed vein samples after antegrade EVH as well as employed conventional alternatives. However, lack of experience and negligence for tissue preservation and vein quality can increase the risk for bleeding and graft injury. Therefore, a continuously optical vein quality control is highly recommended, as well as “tissue-gentle” vein isolation and preservation of especially perivascular tissue. In this regard, it should be noted that the lifted and outward-rotated foot position and a prolonged distance from the minimally-invasive access point to the ankle joint (one index finger) remarkably improved forward-downward movability of the endoscope. Consequently, synergizing antegrade EVH with bridging vein harvesting reduced mechanical stress and enhanced vein graft quality during antegrade EVH of the great saphenous vein from the lower leg.

Antegrade EVH from the lower leg was feasible, demonstrating straightforward graft dissection and adequate graft quality. No blood stasis, no thrombus formation, and low risk for bleeding and tissue damage were observed. Leg positioning and synergizing the antegrade EVH with bridging vein harvest technique were the two main factors leading to procedural success. Great saphenous vein grafts from the lower leg showed normal diameters (approximately 3-4 mm). After graft retrieval, veins usually demonstrated slight spasms, comparable to our institutional experiences for conventional vein harvesting techniques. Therefore, matching of vein grafts from the lower leg with cardiac target vessels was deemed appropriate for CABG. Thus, the introduced antegrade approach was applicable for both legs. In two cases, antegrade EVH from both lower legs was successfully executed. No wound complications were experienced in this small initial series. Patient acceptance of the method was high.

Figure 1
Figure 1: Organization of surgical theatre and specific positioning of legs. (A-C) The instrumental set-up for EVH was prepared and placed near the end of the surgical table. (D) The instrumental set-up for cardiac surgery was placed on the left side of the anesthetized patient. Two foam rollers (dotted line, one half-cylindrical foam roller just above the knee, one full-cylindrical foam roller below the Achilles tendon) were placed below the extended legs. Foot position was lifted and outward-rotated for direct vision on imagined ankle joint (short line), expected minimally invasive access site (bold line), and medial margin of the tibial metaphysis (dashed line). a-z are described in the Table of Materials. Please click here to view a larger version of this figure.

Figure 2
Figure 2: Minimally invasive surgical access and antegrade EVH allowed safe and unimpeded dissection of the great saphenous vein. (A-C) Following sterile draping of patients, the great saphenous vein from the lower leg was isolated and (C) looped through minimally invasive surgical access via the bridging vein harvesting technique. (D-F) The optical dissector was assembled under sterile conditions (D) and inserted antegrade through the inflatable blocker balloon (solid arrow) into the wound (E,F). (G-I) The protocol allowed for a simplified forward-downward movement (dotted arrow) of the optical dissector during EVH (G,H) without impeding the work of the primary surgeon and surgical nurse (I). aa-af are described in the Table of Materials. Please click here to view a larger version of this figure.

Figure 3
Figure 3: Following antegrade EVH, all isolated vein grafts demonstrated adequate quality for CABG. (A-E) After removal of the optical dissector the working channel was blocked with a 5 mL syringe (A, arrow), the optical retractor was assembled, prepared with anti-fog fluid (B), and inserted antegrade through the inflatable blocker balloon into the wound (C). Again, the protocol allowed for a simplified and unimpeded forward-downward movement of the optical retractor during EVH (D,E). (F-I) An anatomical clamp was inserted into a stab incision (F, dotted arrow) and used to clamp the main vessel under endoscopic control before retrieval of the distal portion of the vein (G). Thereafter, another anatomical clamp was inserted into a stab incision at the proximal end of the isolated vein (G) followed by complete retrieval of the vein, proximal venous cannulation, clipping of side branches (H, dashed arrow), and wound closure (I). ag is described in the Table of Materials. Please click here to view a larger version of this figure.

Figure 4
Figure 4: Learning curve for antegrade EVH from the lower leg. A total of 30 great saphenous veins from the lower leg were isolated from 28 CABG patients using antegrade EVH. The graph illustrates an immediate dynamic reduction in time expenditure (min) starting from insertion of the optical dissector until termination of vein graft retrieval. Please click here to view a larger version of this figure.

Figure 5
Figure 5: Antegrade EVH preserved integrity of endothelium and vascular wall. (A-C) Representative images from vein cross sections after antegrade EVH for hematoxylin/eosin staining (A,B), as well as for CD31 immunostaining (C), illustrated normal morphology of vascular wall and completely preserved endothelial integrity, respectively. No differences in histology were detected after comparing all harvesting techniques in the department (open vein harvesting, bridging vein harvesting, antegrade EVH). Please click here to view a larger version of this figure.

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Discussion

It should be stated that we prefer complete arterial coronary revascularization in our department. There is rising evidence that CABG using bilateral internal mammary artery (IMA) grafts can significantly improve long-term survival of patients14,15,16,17. However, there are valid reasons for a "single IMA plus vein grafts" strategy, especially in patients at advanced ages, patients with high risks for surgical site infection, patients in which the radial artery graft is not available, and in cases with chronically occluded coronary target vessels. In these scenarios, this protocol offers a standardized technique for safe antegrade EVH from the lower leg. Optimal vein grafts for CABG will reduce short-term wound complications and improve long-term outcomes with diminished revascularization and higher quality of life1,2,8.

The protocol is based on three essential pillars: (1) specific positioning of the leg, (2) bridging vein harvesting technique for minimally invasive access site, and (3) antegrade EVH in a tensionless working channel. Sufficient leg positioning prevented interference of optical dissector and retractor with the food, guaranteed undisturbed EVH in the surgical theatre, allowed for easy graft preparation through forward-downward movement of the endoscope in the working channel, and reduced the risk of common peroneal nerve lesions. Sufficient bridging vein harvest technique simplified the insertion of endoscopic devices, reduced the tension in the working channel especially near the access site, and minimized the possibility of vein graft damage through improved movability of optical dissector and retractor. Moisturizing the EVH equipment with heparinized saline further simplified antegrade insertion of the EVH equipment as well as allowed for unimpeded endoscope movements. Instead of systemic heparin infiltration, heparin was administered locally in the working channel, which was sufficient here to prevent from both thrombus formation and bleeding. Most importantly, the tensionless working channel allowed for antegrade EVH with minimal risk for graft injury.

In this procedure, the surgeon's attention must be concentrated on several aspects. The working channel must be extended by gas pressure before graft preparation. The optical dissector and retractor must be utilized to enlarge the working channel, and the vein harvester may need to enlarge the minimally invasive access site. To the greatest extent possible, the harvester should preserve perivascular tissue (especially near side branches of the vein graft) and be able to use the precise and tissue-protective bipolar electrocoagulation device for interruption of side branches through free movability of the endoscopic vessel harvesting system. In any case, it is recommended to avoid clips in the working channel before EVH. Harvesting beyond the imagined tibial metaphysis requires a higher level of experience, because the working channel becomes progressively narrow and the graft may be damaged.

Some specific tips for successful antegrade EVH include: Avoid bleeding. It is recommended to avoid a narrow working channel. If necessary, the surgeon should use fine surgical forceps to retract the skin incision during material insertion or enlarge the skin incision with the curved scalpel (and fixate the blocker balloon with an additional intracutaneous U-suture). It should be repetitively evaluated if the working channel is extended by the gas pressure and tension-free. The working channel should be enlarged with the optical dissector or retractor, if necessary. The side branches should be sufficiently dissected with the optical dissector. The integrity of the subcutaneous (especially the perivascular) tissue should be preserved as much as possible, addressing both graft injury prevention and maximal reduction of mechanical stress in the working channel. Surgeons should be aware of sufficient interruption of all side branches from the main vessel with the optical retractor. Additional skin incisions will be required if interruption of side branches was incomplete. Surgeons should be "tissue-gentle" through avoidance of extensive traction forces affecting the vein, especially in chronic venous insufficiency, diabetes, peripheral artery disease, obese, and elderly female patients. Antegrade EVH from the lower leg should be stopped, at the furthest, next to the imagined tibial metaphysis.

Following this protocol, the antegrade EVH approach enables "tissue-gentle" vein preparation at the lower leg, with adequate vein graft quality and low risk of wound complication, even in chronic venous insufficiency, diabetes, peripheral artery disease, obese, and elderly female patients3,8,9,10. Initial randomized histological analyses of vein grafts illustrated completely preserved endothelial and vessel wall integrity after all harvesting techniques in the department (open vein harvesting, bridging vein harvesting, antegrade EVH). Moreover, antegrade EVH from the lower leg illustrated vein grafts with low side-branching and adequate matching of conduit and target vessels during CABG. Therefore, it was hypothesized that this approach may be advantageous compared to the antegrade EVH approach from the upper leg in follow-up studies. Vein grafts harvested from the knee and upper leg usually show frequent side branching and occasional mismatching of dilated conduit vessels (diameters above 5 mm) with coronary target vessels, which can create more turbulent intraluminal flow conditions and lead to an increased risk for graft occlusion after CABG11.

Further, the proposed technique may eliminate a majority of wound complications, especially after open vein isolation in the region of the knee where wound healing can be compromised due to tissue tension during post-operative mobilization of the patient. The manuscript lacks a systematic in-depth analysis of vein graft histology and its endothelial functionality. However, initial data point to possible non-inferiority of antegrade EVH compared to other harvesting techniques. The protocol emphasizes maximal protection of the surrounding subcutaneous (especially perivascular) tissue, addressing both preserved graft integrity and reduced mechanical stress in the working channel. Further studies are required on controlling the graft long-term patency. The small sample of patients may implicate that the learning curve is not finished. Therefore, the protocol for antegrade EVH from the lower leg was established and performed by surgeons experienced with the technique for the upper leg, which should guarantee sufficient vein graft quality18,19. Further investigation is warranted.

Antegrade EVH with the endoscopic vessel harvesting system produced additional peri-operative procedural costs during CABG and is not reusable. However, cost efficiency was proven, and the closed tunnel EVH system demonstrates multiple highly appreciated advantages over existing reusable or open EVH techniques2,20. In this set-up, a closed tunnel EVH system was chosen because it offers a long (maximum 35-40 cm), small lumen working channel and allows for antegrade EVH from the lower leg with only one minimally invasive skin incision. A single switch from optical dissector to optical retractor and the integration of directed, precise, and graft-protective electrocauterisation enabled a short time expenditure and optimized cost efficiency, quality of life, and vein graft histology2. Moreover, the antegrade approach can be applied for the full length of the leg if a second small incision (standard incision, recommended by the manufacturer) is added next to the imagined tibial metaphysis. As shown, antegrade EVH of the great saphenous vein can be repeated in the second lower leg. Apart from that, antegrade EVH of the small saphenous vein was enabled through specific positioning of the leg with lifted and inward-rotated foot position and lateral minimally invasive access site in two patients (unpublished data by A. Kaminski, 2018), comparable with the work of Rustenbach et al.21

The introduced antegrade EVH concept for the great saphenous vein from the lower leg illustrates feasibility for straightforward graft dissection and adequate graft quality, indicating a promising clinical perspective for routine use in CABG. The protocol has a steep learning curve in experienced cardiac surgeons. Besides the explained benefits, the antegrade EVH approach for the great saphenous vein from the lower leg displayed low risks for blood stasis, thrombus formation, bleeding, and graft injury, which was previously seen with the conventional retrograde approach. For these reasons, we had cancelled the retrograde approach earlier in patients before starting this study. However, there is a lack of data supporting a general assumption of superiority of the antegrade over the retrograde approach.

Absence of blood stasis (with augmented intravenous blood pressure because of closed venous valves) and limited mechanical stress on the vein may reduce the risk for graft injury and thrombosis as well as improve long-term patency of bypass grafts18,22. The data showed that all great saphenous veins isolated by antegrade EVH were adequate grafts for CABG surgery with respect to general macroscopic and randomly selected microscopic evaluations. However, we discarded distal vein graft parts with major injuries resulting from EVH preparation in an inadequately narrow working channel in the early phase of the learning curve. There were no graft injuries during the last 21 EVH procedures. The cardiac surgeon should not accept inadequate bypass graft material, because in these cases, graft occlusion is more frequent and could worsen clinical outcomes23.

A study by Kodia et al. underlined that currently applied EVH protocols should be advanced in order to improve vein graft quality5. Nonetheless, a recent prospective randomized controlled trial clearly depicted that closed tunnel EVH demonstrated gains in quality of life, superior cost-effectiveness, and minor differences in graft integrity compared to open vein harvesting without affecting major adverse cardiac event (MACE) rate after CABG surgery2. Another prospective pilot study similarly showed improved post-operative physical recovery, better quality of life, and equal MACE rates after CABG with EVH compared to open vein harvesting24. Moreover, the question arises whether or not post-operative outcome after CABG with vein grafts isolated by conventional EVH (in clear majority from the upper leg) may be further enhanced with the described antegrade EVH approach for the lower leg. Follow-up studies are warranted. Experienced surgeons and a structural, protocol-based education of inexperienced colleagues may help maintenance of a higher vein graft quality standard isolated by antegrade EVH and broadening of the technique. Besides isolated and combined CABG scenarios, EVH was also shown to be feasible in elective and high-urgency peripheral bypass grafting scenarios25,26. However, caution should be taken. In high-urgency CABG scenarios, a higher level of experience in EVH is required in order to minimize the time exposure and guaranty adequate vein graft quality.

In conclusion, antegrade EVH from the lower leg is a safe method for the isolation of venous graft material for CABG. Macroscopic evaluation and initial histological analyses demonstrated excellent graft quality with preserved endothelial integrity, and this leads to promising clinical results underlining that the method may be a valid alternative to conventional antegrade EVH from the upper leg. Also illustrated is a steep learning curve in experienced cardiac surgeons and low risks for graft-associated complications. The protocol offers a specific institutional step-by-step procedure for antegrade EVH from the lower leg with practical hints, troubleshooting, and possible solutions. Three essential pillars for success were highlighted: (1) specific positioning of the leg, (2) synergizing with bridging vein harvesting technique for minimally invasive access site, and (3) antegrade EVH in a tensionless working channel under continuously optical control of vein graft quality. Therefore, it is proposed that this protocol may help both cardiac and vascular surgeons in developing optimal approaches for high-quality vein graft isolation.

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Disclosures

Manuscript publication was funded by Getinge Group (Germany). Alexander Kaminski is a consultant to Getinge Group and receives speaker honoraria from Getinge Group. All authors declare study conduction and entire scientific analyses were executed independently from industrial partners. All authors declare responsibility for the integrity of the work as a whole and have given final approval to the version to be published. All authors declare that there are no conflicts of interest.

Acknowledgments

We thank the entire surgical staff for excellent technical assistance.

Materials

Name Company Catalog Number Comments
disposable scalpel (size 11, Präzisa Plus) Dahlhausen, Germany a
small curved smooth (anatomical) clamps B. Braun Aesculap, Germany b
toothed (surgical) forceps B. Braun Aesculap, Germany c
surgical scissors B. Braun Aesculap, Germany d
holder for scalpel blade (size 10) B. Braun Aesculap, Germany e
fine smoth (anatomical) forcep B. Braun Aesculap, Germany f
sponge-holding clamp B. Braun Aesculap, Germany g
clipping device Fumedica, Switzerland h
18 Gauge cannula (Sterican) B. Braun, Germany i
light handle Simeon Medical, Germany j
needle holder B. Braun Aesculap, Germany k
tissue retractor B. Braun Aesculap, Germany l
Redon needle B. Braun Aesculap, Germany m
adhesive hook and loop fastener Mölnlycke, Germany n
extended length endoscope Karl Storz, Germany o
optical cable Karl Storz, Germany p
transparent drap camera cover ECOLAB Healthcare, Germany q
connection cable for electrocauterisation Maquet, Getinge Group, Germany r
gas insufflation set Dahlhausen, Germany s
Fred Anti-Fog Solution Medtronic, USA t
bipolar electrocoagulation device Maquet, Getinge Group, Germany u
monitor (WideView) Karl Storz, Germany v
light source (xenon 300) Karl Storz, Germany w
gas insufflation controller (Endoflator) Karl Storz, Germany x
half-cylindrical foam roller Almatros, Gebr. Albrecht KG, Germany y
full-cylindrical foam roller Almatros, Gebr. Albrecht KG, Germany z
bulldog clamp B. Braun Aesculap, Germany aa
flexible vessel cannula Medtronic, USA ab
vessel loop (Mediloops) Dispomedica, Germany ac
Heparin-Natrium (5000 U) in 200ml saline B. Braun, Germany ad
Langenbeck hooks B. Braun Aesculap, Germany ae
sutures (polygalctin 910, Vicryl 2-0, 4-0; poly ethylene terephthalate, Ethibond 2-0) Ethicon, Johnson & Johnson, USA af
Endoscopic vessel harvesting system, Vasoview Hemopro II Maquet, Getinge Group, Germany ag
Octenidindihydrochloride, Octeniderm Schuelke & Mayr GmbH, Germany

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References

  1. Kopjar, T., Dashwood, M. R. Endoscopic Versus "No-Touch" Saphenous Vein Harvesting for Coronary Artery Bypass Grafting: A Trade-Off Between Wound Healing and Graft Patency. Angiology. 67, (2), 121-132 (2016).
  2. Krishnamoorthy, B., et al. Study Comparing Vein Integrity and Clinical Outcomes in Open Vein Harvesting and 2 Types of Endoscopic Vein Harvesting for Coronary Artery Bypass Grafting: The VICO Randomized Clinical Trial (Vein Integrity and Clinical Outcomes). Circulation. 136, (18), 1688-1702 (2017).
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