Procedure

The no-touch technique of harvesting the saphenous vein for coronary artery bypass grafting surgery

^a Department of Thoracic and Cardiovascular Surgery, Örebro University Hospital, Örebro, Sweden
^b Department of Cardiovascular Surgery, Anis Rassi Hospital, Goiânia, Brazil
^c Department of Laboratory Medicine, Örebro University Hospital, Örebro, Sweden

^* Corresponding author: Dr. Domingos S.R. Souza, Department of Thoracic and Cardiovascular Surgery, Örebro University Hospital, SE-701 85 Örebro, Sweden. Tel.: +46 19 6025204 (Office); +46 19 247151 (Home); fax: +46 19 6113943. domingos.souza{at}orebroll.se

	Summary

Top Summary Introduction Surgical procedure Randomized study Results Conclusions Acknowledgements References

 
A new ‘no-touch’ (NT) technique of saphenous vein (SV) preparation for coronary artery bypass grafting (CABG) surgery was developed where the vein is harvested with a pedicle of surrounding tissue, which protects the vein from spasm therefore obviating the need for distension. The adventitial layer and the structures contained within the cushion of surrounding tissue possess both mechanical and functional properties that protect the vein from spasm and ischemia. In addition, the surrounding tissue supports excessively long vein grafts and prevents kinking. A detailed description of the technique is presented and this is the first time we publish the technique as a videoclip.

Key Words: CABG • No-touch technique • Saphenous vein harvesting

	Introduction

Top Summary Introduction Surgical procedure Randomized study Results Conclusions Acknowledgements References

 
Despite the widespread use of the internal thoracic artery (ITA) and other arterial conduits, the saphenous vein (SV) continues to be the most commonly used conduit for coronary artery bypass grafting (CABG). However, vein graft failure is associated with recurrence of angina [1] and is one of the primary reasons for reoperation. Vein graft failure occurs in 10% within the first month of implantation, and about 15–30% [2] of SV grafts occlude within the first year [3]. At 10 years, graft occlusion rates are >50% [1] and the grafts that remain patent frequently show angiographic evidence of luminal narrowing. Accordingly, for the SV grafts to remain useful as stable and long-lasting coronary bypass conduit, graft thrombosis and atherosclerosis, which are the most important pathologic changes causing graft failure, must be delayed or prevented.

Preparation of the graft is an important issue since there is direct evidence that injury during surgery causes severe intimal loss as well as biochemical and functional changes of the graft [4]. During harvesting of the SV, a pronounced and protracted spasm occurs and it is triggered when removing the perivascular tissue adherent to the vein (Photo 1). Various pharmacological agents have been used to relax the vein [5, 6], but high-pressure distension of the vein is often required to overcome the spasm and establish a lumen adequate for grafting. It therefore seems reasonable to assume that dissection, manipulation, and distension of the SV induce damage to the media and intima of the graft that impacts on its performance.

View larger version (131K): [in this window] [in a new window]   Photo 1 Vein spasm triggered by the removal of perivascular tissue. The same segment of saphenous vein before and after removal of the perivascular layer.

	Surgical procedure

Top Summary Introduction Surgical procedure Randomized study Results Conclusions Acknowledgements References

 
Preoperative vein mapping using B-mode ultrasonography is fundamental to optimise the NT technique (Photo 2). The course of the vein should be marked on the overlying skin. This facilitates rapid and accurate location of the vein at operation, thus reducing soft tissue injury and the creation of tissue flaps that could lead to wound complications. This is of particular importance in obese patients. In addition, information is obtained to aid selection of the best vein segments for grafting (Videos 1, 2, 3, Photo 3, Videos 4, 5, 6, 7).

View larger version (109K): [in this window] [in a new window]   Photo 2 Mapping of the saphenous vein.

Click on image to view video Video 1 Skin incision. A longitudinal incision is made through the skin and the subdermal vessels ligated to avoid overuse of diathermy. Incisions at the knee level should be avoided as this region of the SV has a larger number of branches and the vein at this level is often of inferior quality. Furthermore, it is more comfortable for the patient if an incision crossing the knee is avoided. Consequently, we recommend performing the incision on the calf and on the thigh separately.

Click on image to view video Video 2 Exposure of the saphenous vein. The edge of the wound is elevated using forceps, and with the subcutaneous tissue under tension a plane is created around the vein using scissors. The vein is protected by a thin layer of adherent tissue anteriorly and posteriorly and by a 0.5-cm of fat on either side.

Click on image to view video Video 3 Removal of the vein. The SV, together with its perivascular tissue, is separated from its bed using scissors and diathermy, and all branches are dissected, ligated, and divided at the edge of the pedicle. A segment of the vein from the calf and another from the thigh were removed.

View larger version (85K): [in this window] [in a new window]   Photo 3 Saphenous vein removed from its bed without any spasm. This continuous cushion of perivascular tissue protects the vein from direct handling by surgical instruments and dramatically reduces the incidence of venous spasm. The vein is then left in situ covered with saline-soaked swabs until it is going to be used. After excision, the vein is stored in blood obtained from the aortic cannula.

Click on image to view video Video 4 Performance of the distal anastomosis and checking for leakage. While performing the anastomosis, the perivascular tissue is used to grasp the vein, thereby avoiding direct contact between the vein and instruments. After each distal anastomosis is completed, the graft is perfused with blood from the arterial cannula for 10 s to detect any bleeding from the anastomosis or missed side branches. This is performed through a three-way stopcock delivery system. The vein should never be distended manually. If using off-pump CABG, checking for bleeding from the grafts and anastomoses would be done at the time of graft perfusion. A good method to check for leakage in off-pump surgery is to perform the proximal anastomoses first and then perfuse the grafts with blood from the aorta.

Click on image to view video Video 5 The vein being perfused after removal of aortic cross-clamping. After removal of the aortic cross-clamp and before suturing the proximal anastomoses, all vein grafts are connected to the arterial line to allow early myocardial perfusion. This procedure also helps to determine the graft length, to recheck and identify any further bleeding, as well as to maintain relaxation of the vein.

Click on image to view video Video 6 Performance of the proximal anastomoses, final check for leakage and measurement of graft flow. After completing the proximal anastomoses and before weaning the patient from ECC, it is very important to perform a final check for leakage of all grafts and all anastomoses. The graft flow was routinely measured by the transit time flowmeter (Veriq system, VQ 4122, Medistim AS, Oslo, Norway).

Click on image to view video Video 7 Leg wound closure. The leg wounds are closed with interrupted or continuous 3-0 suture to the subcutaneous tissue and a continuous subcuticular undyed 4-0 absorbable monofilament suture to the skin.

	Randomized study

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Material and methods
One hundred and fifty-six patients who underwent CABG at the Department of Cardiothoracic Surgery, University Hospital, Örebro, Sweden, were randomly allocated to three groups of 52 patients, according to three techniques of harvesting the SV.

Group C: Conventional technique: The vein was exposed by a continuous longitudinal incision, the adventitial layer was stripped and side branches ligated. The vein was removed from the leg immediately after dissection and was manually distended with saline at 300 mmHg for 1 min, using a syringe connected to a manometer. After distension, the vein was stored in saline at room temperature.

Group I: Intermediate technique: The vein was dissected as in group C. Instead of manual distension the vein was subjected to the following procedure: It was left in situ and covered by sponges moistened with saline–papaverine solution (1 mg/ml) until extracorporeal circulation was started. The vein was then removed and stored in blood obtained from the aortic cannula before cooling.

Group NT: ‘No-touch’ technique. The vein was prepared as described in this video presentation.

Morphological and immunohistochemical assessment
SV samples were obtained from some patients for both morphological assessment, using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and immunohistochemical studies.

Angiographic assessment
An angiographic follow-up was performed at mean time 18 months and was repeated at 8.5 years after operation.

	Results

Top Summary Introduction Surgical procedure Randomized study Results Conclusions Acknowledgements References

 
Morphological findings

• The morphological studies using SEM indicated that preservation of the endothelial integrity was better with the new NT technique. The TEM showed that the endothelium was continuous and attached to the basal membrane for the NT veins while the veins which were treated with the conventional technique showed frequently a discontinuous endothelium with detached endothelial cells separated from the basal membrane [8, 9, 10].
  

Immunohistochemical findings

• The CD31 immunostaining, identifying endothelial cells, confirmed that the endothelial cell integrity of ‘NT’ grafts was well preserved, whereas in conventionally harvested veins it was reduced [11].
  
• In an autoradiographic assessment for localisation of nitric oxide synthase (NOS) there was endothelium-dependent radioligand binding on the luminal aspect of vessels, which was almost continuous on the ‘NT’ segments, but reduced on the conventionally prepared segments [11].
  
• Also, all three isoforms of NOS were identified in the media, contributing to the positive NADPH-diaphorase staining. In the intact adventitia of ‘no-touch’ vessels, abundant NOS III (eNOS) positive staining was associated with microvessels, and this coincided with positive CD31 staining. These microvessels also stained positive for NOS II (iNOS). NOS I (nNOS) immunostaining was associated with adventitial perivascular nerves [12, 13, 14, 15].
  

Surgical data

• The majority of patients in all groups received three vein grafts and an ITA. A total of 127 vein grafts and 41 ITA grafts were inserted in group C. In group I, a total of 116 vein grafts and 35 LITA grafts were used and in group NT, a total of 124 vein grafts and 42 ITA grafts were implanted.
  
• No operative mortality occurred in the three groups. Preoperative myocardial infarction occurred in two patients in group C. There was one reoperation to control postoperative bleeding performed in one patient in group NT, where the source of the bleeding was from the ITA bed. Only minor wound complications were seen in a few cases in all the three groups. Two of 46 patients (4.3%) in group C, three of 41 patients (7.3%) in group I and five of 45 (11.1%) in group NT developed superficial infection or cellulitis. We had no major complication that required subsequent surgical intervention [16].
  

Graft patency

• One hundred and thirty-two patients, 46 patients from group C, 41 from group I and 45 from group NT underwent an angiographic follow-up at mean time 18 months after the operation. The remaining 24 patients declined the angiographic assessment. The patency for NT was 118/124 (95.4%), for grafts in group C was 113/127 (88.9%) and for grafts in group I was 100/116 (86.2%). The patency for LITA was 108/118 (91.5%) [16].
  
• Another angiographic assessment was performed at mean time 8.5 years in 37 patients from both C and NT groups. Due to limited economic resources, we did not evaluate patients from the intermediate group. An additional reason for exclusion was that this group had the lowest patency rate at the 18-month assessment. At this time, the patency rate was 76% (77/101) for group C and 90% (91/101) for group NT (P=0.01) [17].
  
• The patent grafts that had a flow rate below 40 ml/min were 36/50 (72%) in group C vs. 44/46 (95.7%) in the NT group (P=0.002) (Video 8).
  
• No kinking will occur in veins supported by the surrounding tissue. This may be an additional contributory factor explaining the high patency rate (Video 9).
  
• All sequential grafts in the NT group were still patent at mean time 8.5 years after the operation (Video 10).
  

Click on image to view video Video 8 Angiographies showing vein grafts anastomosed to small size coronary arteries. A high patency rate was found in grafts which had low flow.

Click on image to view video Video 9 Angiographies of excessively long grafts. The risk for kinking in excessively long grafts is avoided since the perivascular tissue supports the vein wall.

Click on image to view video Video 10 Angiographies of sequential grafts. No occlusion was observed even with multiple sequential grafting.

	Conclusions

Top Summary Introduction Surgical procedure Randomized study Results Conclusions Acknowledgements References

	Acknowledgements

Top Summary Introduction Surgical procedure Randomized study Results Conclusions Acknowledgements References

 
We would like to thank Lars-Göran Jansson from the Department of Medical Photography, Örebro University Hospital for his expert work in producing the video sequences.

	Footnotes

 
This study was supported by the financial funding from the Swedish Heart Lung Foundation and the joint Örebro-Värmland Research grants.

	References

Top Summary Introduction Surgical procedure Randomized study Results Conclusions Acknowledgements References

 

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14. Dashwood MR, Savage K, Dooley A, Shi-Wen X, Abraham DJ, Souza DSR. Effect of vein graft harvesting on endothelial nitric oxide synthase and nitric oxide production. Ann Thorac Surg 2005;80:939–944.[Abstract/Free Full Text]
15. Dashwood MR, Dooley A, Shi-Wen X, Abraham DJ, Souza DS. Does periadventitial fat-derived nitric oxide play a role in improved saphenous vein graft patency in patients undergoing coronary artery bypass surgery? J Vasc Res 2007;44:175–181.[CrossRef][Medline]
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