Eur J Cardiothorac Surg 1998;14:602-606
© 1998 Elsevier Science NL
Tunnelling versus open harvest technique in obtaining venous conduits for coronary bypass surgery
Hanh M. Trana,
Hugh S. Patersona,b,
William Meldrum-Hannaa,
Richard B. Charda
a Department of Cardiothoracic Surgery, Westmead Hospital, Westmead, NSW, Australia 2145
b Department of Surgery, Sydney University, Sydney, NSW, Australia
Received 8 June 1998;
received in revised form 29 September 1998;
accepted 6 October 1998.
Corresponding author. Tel.: +61-2-9845-7994; fax: +61-2-9845-7440.
 |
Abstract
|
|---|
Background: The tunnelling as opposed to the open harvest technique for harvesting long saphenous vein for coronary artery bypass procedures is a less frequently used technique as it requires more handling of the vein and this may induce trauma. This study aims to compare the degree of endothelial denudation and donor site morbidity between the two different harvest techniques. Methods: Saphenous vein segments in 78 patients (45 in tunnelling versus 33 in open harvest group) undergoing coronary artery bypass procedures were examined by light microscopy and graded according to the extent of endothelial denudation varying from grade 1 (most preserved) to grade 6 (>90% endothelial denudation). Clinical parameters relating to donor site morbidity including leg wound pain and infection were also assessed. Results: There was no statistical difference in the age, sex, macroscopic vein quality, length and time taken to harvest the veins between the two groups. The tunnelling technique always used thigh saphenous vein whereas nearly a third of veins harvested by the open harvest technique were lower leg veins (P=0.001). The tunnelling technique resulted in an endothelial score of 2.5 compared with 3.3 for the open harvest technique (P<0.001). In addition, saphenous vein tunnelling resulted in significantly less leg wound pain (1.2 vs. 1.8, P=0.001), no leg wound infection (compared with 12.2% in open harvest group, P=0.02) and produced cosmetically more acceptable scars. Furthermore, length of hospital stay was significantly prolonged to 19.3 days in those with leg wound infection compared to 8.7 days in those without leg wound infection (P<0.001). Conclusions: These results show that saphenous vein tunnelling is an attractive alternative to the open harvest technique in obtaining venous conduits for coronary artery bypass procedures.
Key Words: Endothelial preservation • Saphenous vein • Coronary bypass
|
Introduction
|
|---|
Coronary artery bypass procedures utilizing venous conduits rather than internal mammary arteries are known to have a lower long-term patency rate
[1]
[2]. This is thought to be the result of arterialization of the vessel wall resulting in progressive luminal narrowing and eventual occlusion such that vein grafts are often revised after 8–12 years
[3]
[4]. In addition, poor vein quality may contribute to early occlusion especially if the distal run-off is borderline, with implications in terms of morbidity and mortality
[5]
[6].
Traditionally, the saphenous vein is harvested by the open harvest technique as this allows direct visualization and potentially reduces handling to minimize endothelial damage. In a few centres, the saphenous vein is harvested utilizing a tunnelling technique which involves multiple small incisions. Apart from producing more cosmetically acceptable scars, there is a lower incidence of wound infection
[7]. However, proponents of the open harvest technique argue that tunnelling induces excessive damage to the saphenous vein and would jeopardize its patency rate, both short and long term. The aim of this study is to assess the degree of endothelial damage in saphenous vein segments harvested by the open compared to the tunnelling technique. In addition, the following clinical parameters were also assessed: age, sex, site of harvest, length of vein and time taken to harvest, macroscopic quality of the vein, grade of harvesting surgeon, post-operative wound pain, incidence of wound infection and duration of hospital stay. This study was approved by the Scientific Advisory Committee and the Human Research Ethics Committee of the Western Sydney Area Health Service.
|
Materials and methods
|
|---|
This study is made possible because two of the surgeons (H.S.P. and B.M.H.) use the tunnelling technique while the other surgeon (R.B.C.) routinely used the open harvest technique to obtain the long saphenous vein for coronary bypass procedures at Westmead Hospital.
Operative procedures
The tunnelling technique involves multiple small incisions along the course of the long saphenous vein mostly starting from the groin. After the vein is suture ligated and divided from the sapheno-femoral junction it is dissected free from surrounding tissues and its branches clipped on the patient's side and cut. Usually 5–10 cm of the vein can be freed in this way before the introduction of a tunneller (Mayo vein stripper; Johnson and Johnson) (
Fig. 1
) which is brought out through a more distal incision together with the vein. The process is repeated until the desired length of the vein is harvested. The open harvest technique exposes the saphenous vein throughout its harvested length. It remains connected both proximally and distally until the branches are either suture ligated or clipped and cut when the desired length of the vein is removed. After harvest, the vein is secured to a Tibbs cannula and distended in length after occluding the proximal end with an atraumatic bulldog clamp. The saphenous vein is distended using a 20 ml syringe containing heparinized Ringer's solution at room temperature and with gentle manual pressure. The saphenous vein is normally taken in excess to ensure sufficient length. In most cases, the long saphenous vein is harvested from either the groin or ankle to just beyond the knee. The anastomoses for grafting the coronary arteries are performed sequentially with the most distal first before eventually performing the proximal anastomosis to the aorta. The excess venous segments (normally 5–10 cm) were placed in heparinized Ringers solution until the end of the case and then stored in buffered formalin containers. Only segments greater than 2 cm from the cannula tips were used to negate spurious endothelial damage secondary to cannulation.
Clinical parameters
- Age and sex
- Harvest site: leg and/or thigh
- Length of distended vein in centimetres
- Harvest time. This starts with skin incision and ends with complete skin closure and includes vein preparation
- Macroscopic quality the harvested saphenous vein. The following was used as a guideline: Grade 1: Excellent calibre (4–6 mm) and thickness with no varicosities. Grade 2: Good calibre and thickness with 1–2 varicosities or a tear requiring repair. Grade 3: Thick or thin-walled, multiple varicosities, or 2 or more tears requiring repair. Grade 4: Combination of any 2 imperfections in grade 3.
- Surgeon: Consultant or registrar
- Post-operative leg wound pain (at day 5): 1, no pain; 2, mild; 3, moderate; 4, severe.
- Leg wound infection. This is defined as either cellulitis requiring antibiotic therapy or deep wound infection requiring incision and drainage.
- Length of hospital stay in days.
- Histological grading of endothelial damage (see Table 1).
Laboratory procedures
All vein segments were collected in a sterile container with buffered formalin until analysis. A 1 cm segment was cut longitudinally and splayed open with pins placed at corners. The tissue was first washed in phosphate buffered saline before being placed in haematoxylin for 90 seconds. The specimen was then rinsed off with water, 70% alcohol and water and then placed in eosin for 10 seconds. The eosin was then rinsed off with 70% alcohol. The above staining technique allows diffusion and staining of a few superficial endothelial layers of cells, permitting a clear visualization of the endothelium under the light microscope
[8]. All venous segments were graded for degree of endothelial denudation by the author (HMT) without knowledge of each individual specimen's grouping.
Statistical analysis
Statistical significance between the two groups, Tu (vein harvested by tunnelling) and Op (vein harvested by open cut) was established using Chi-squared, Fischer's exact, one-way ANOVA, and Mann-Whitney rank sum tests. The data were analyzed using the statistical software package SPIDA (version 6, 1992, Statistical Computing Laboratory, Macquarie University, Sydney, Australia).
|
Results
|
|---|
There was no statistical difference between the age and sex of patients between the two groups. The average age was 64.4 years for group Tu and 62.3 years for group Op (one-way ANOVA, P=0.25). The sex distribution was 37 males and 8 females for group Tu and 22 males and 11 females for group Op (Chi-squared, P=0.11). The tunnelling technique always utilized the thigh vein but frequently extended to below the knee. In contrast, 10 out 33 of the saphenous veins harvested using the open harvest technique were lower leg veins (Chi-squared, P=0.001) (Table 2). There was no statistical difference in the length, duration taken to harvest saphenous vein and the macroscopic quality of the vein between the two groups (Table 3). The amount of post-operative leg wound pain was 1.2 for group Tu and 1.8 for group Op (Mann–Whitney U-test, P=0.001). There was no leg wound infection in group Tu compared with 12.2% in group Op (Fischer's exact test, P=0.02). The average hospital stay was 7.7 days for group Tu and 10.1 days for group Op (Mann–Whitney U-test, P=0.15) (Table 4). However, for those patients with infected vein harvest site, the average hospital stay was prolonged to 19.3 days (Mann–Whitney U-test, P=0.026) compared with 8.7 days in those without vein harvest site infection.
Using the histological criteria in Table 1, the grading of venous segments varied from 1.5 (minor lineation) to 5 (up to 90% denudation) for both groups. However, venous segments in group Tu had more preserved endothelium with an endothelial grading of 2.5 compared with 3.3 in group Op (Mann–Whitney U-test, P<0.001) (Table 5). Furthermore, there was no statistical difference between the grade of the harvesting surgeon and the endothelial grading of venous segments within group Tu (Table 6).
|
Discussion
|
|---|
This study utilized the extent of endothelial denudation as an endpoint to assess the amount of trauma induced on harvested long saphenous vein by the tunnelling and open harvest techniques. The tunnelling technique resulted in a more preserved endothelial architecture than the open harvest technique suggesting that factors other than direct handling during vein harvest are equally if not more important. One constant observation of the harvesting procedure is that the long saphenous vein is nearly always more contracted when harvested as an open harvest than when it is tunnelled. It is possible that the vigorous smooth muscle cell contraction seen in the open harvest group is associated with the most endothelial damage. It has been previously shown that prolonged contraction of a vein leads to endothelial protrusion and sloughing
[9]
[10]. In addition, the excessively contracted vein would require increased distending pressure and this potentially further enhances endothelial denudation
[8]
[11]. The use of topical vasodilatators on the vein during the open harvest technique has been shown to improve endothelial preservation
[10] but these were not used in this series. The majority of vein harvesting was performed by the registrar surgeons (Table 2) who each worked with all consultants and performed both techniques. The tunnelling technique, quite apart from producing cosmetically more acceptable scars also resulted in no leg wound infection which is consistent with the 0.9% wound complication rate, all of minor proportions, reported by Meldrum-Hanna et al.
[7] in 2439 patients undergoing this procedure. In contrast, the open harvest technique resulted in a leg wound infection rate of 12.2% and this is consistent with reported frequencies of impaired wound healing of open harvest site incisions
[12]. In this study the patients with an infected vein harvest site had a more prolonged hospital stay of 19.3 days compared to 8.7 days in those without leg wound infection. In conclusion, based on the parameters studied including the extent of endothelial damage, saphenous vein tunnelling appears a superior alternative to the open harvest technique as a means of obtaining venous conduits for coronary artery bypass procedures. It seems likely that endoscopic saphenous vein harvesting with the use of a modified Mayo vein stripper will also be associated with improved endothelial preservation relative to open harvest techniques. However, the tunnelling technique described in this paper requires no disposable instruments and the harvest times are less than those reported for the endoscopic technique
[13] resulting in a substantial cost-benefit.
|
Acknowledgments
|
|---|
The authors wish to thank Dr. J. Davidson for her technical assistance and Dr. Karen Bigh for her statistical analysis.
|
References
|
|---|
- Acinapura A.J., Jacobowitz I.J., Kramer M.D., Zisbrod Z., Cunningham J.N. Internal mammary artery bypass: thirteen years of experience. Influence of angina and survival in 5125 patients. J Cardiovasc Surg 1992;33:554-559.[Medline]
- Tector A.J., Kress D.C., Downey F.X., Schmahl T.M. Complete revascularization with internal thoracic artery grafts. Semin Thorac Cardiovasc Surg 1996;8:29-41.[Medline]
- Weintraub W.S., Jones E.L., Craver J.M., Guyton R.A. Frequency of repeat coronary bypass or coronary angioplasty after coronary artery bypass surgery using saphenous venous grafts. Am J Cardiol 1994;73:103-112.[Medline]
- Davies M.G., Hagen P.O. Pathophysiology of vein graft failure: a review. Eur J Vasc Endovasc Surg 1995;9(1):7-18.[Medline]
- Campeau L., Enjalbert M., Lesperance J., Vaislic C., Grondin C.M., Bourassa M.G. Atherosclerosis and late closure of aorto-coronary saphenous vein grafts: sequential angiographic studies at 2 weeks, 1 year, 5–7 years and 10–12 years after surgery. Circulation 1983;68(Suppl. II):1.
- Sasaki Y., Ueda M., Suehiro S., Shibata T., Minamimura H., Hattori K., Kinoshita H. Early changes at anastomotic sites of saphenous vein grafts after coronary artery bypass grafting. Nippon Geka Gakkai Zasshi 1995;96:466-472.[Medline]
- Meldrum-Hanna W., Ross D., Johnson D., Deal C. An improved technique for long saphenous vein harvesting for coronary revascularization. Ann Thorac Surg 1986;42:90-92.[Abstract]
- Dries D., Mohammad S.F., Woodward S.C., Nelson R.M. The influence of harvesting technique on endothelial preservation in saphenous veins. J Surg Res 1992;52:219-225.[Medline]
- Baumann F.G., Catinella F., Cunningham J., Spencer F. Vein contraction and smooth muscle cell extensions as causes of endothelial damage during graft preparation. Ann Surg 1981;194(2):199-211.[Medline]
- Roubos N., Rosenfeldt F.L., Richards S.M., Conyers R.A., Davis B.B. Improved preservation of saphenous vein grafts by the use of glyceryl trinitrate-verapamil solution during harvesting. Circulation 1995;92:31-36.[Abstract/Free Full Text]
- LoGerfo F.W., Quist W.C., Crawshaw H.M., Haudenschild C.C. An improved technique for the preservation of endothelial morphology in vein grafts. Surgery 1981;90:10-15.[Medline]
- Wepke-Tevis D.D., Stotts N.A., Skov P., Carrieri-Kohlman V. Frequency, manifestations, and correlates of impaired healing of saphenous vein harvest incisions. Heart lung 1996;25(2):108-116.[Medline]
- Cable D.G., Dearani J.A. Endoscopic saphenous vein harvesting: minimally invasive video-assisted saphenectomy. Ann Thorac Surg 1997;64:1183-1185.[Abstract/Free Full Text]
This article has been cited by other articles:
|
|
|
|
 
V. Dusterhoft, M. Bauer, S. Buz, B. Schaumann, and R. Hetzer
Wound-healing disturbances after vein harvesting for CABG: a randomized trial to compare the minimally invasive direct vision and traditional approaches
Ann. Thorac. Surg.,
December 1, 2001;
72(6):
2038 - 2043.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
V. Agarwal, S. K Agarwal, N. K Gupta, and A. K Srivastava
Minimally Invasive Saphenous Vein Harvesting Using Conventional Instruments
Asian Cardiovasc Thorac Ann,
September 1, 2001;
9(3):
246 - 247.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. M. Fabricius, A. Diegeler, N. Doll, H. Weidenbach, and F. W. Mohr
Minimally invasive saphenous vein harvesting techniques: morphology and postoperative outcome
Ann. Thorac. Surg.,
August 1, 2000;
70(2):
473 - 478.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. Goel, N. M. Sankar, S. Rajan, and K. M. Cherian
Use of direct laryngoscope for better exposure in minimally invasive saphenous vein harvesting
Eur. J. Cardiothorac. Surg.,
February 1, 2000;
17(2):
182 - 183.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. A. Carpino, K. R. Khabbaz, R. M. Bojar, H. Rastegar, K. G. Warner, R. E. Murphy, and D. D. Payne
CLINICAL BENEFITS OF ENDOSCOPIC VEIN HARVESTING IN PATIENTS WITH RISK FACTORS FOR SAPHENECTOMY WOUND INFECTIONS UNDERGOING CORONARY ARTERY BYPASS GRAFTING
J. Thorac. Cardiovasc. Surg.,
January 1, 2000;
119(1):
69 - 76.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
