Asian Cardiovasc Thorac Ann 2008;16:134-138
© 2008 Asia Publishing EXchange Ltd
Endoscopic vs Conventional Vein Harvesting: a Prospective Analysis
Karthik R Vaidyanathan, MS,
Madhu N Sankar, PhD,
Kotturathu M Cherian, FRACS
Department of Cardiac Surgery, Frontier Lifeline and Dr KM Cherian Heart Foundation, International Center for Cardiothoracic and Vascular Diseases, Chennai, India
For reprint information contact: Karthik R Vaidyanathan, MS, Tel: 91 44 4201 7575, Fax: 91 44 2656 5150, Email: rkvdoc{at}rediffmail.com, Frontier Lifeline and Dr. KM Cherian Heart Foundation, International Center for Cardiothoracic and Vascular Diseases, R-30 Ambattur Industrial Estate Road, Chennai 600101, India.
 |
ABSTRACT
|
|---|
Minimally invasive vein harvesting is associated with better leg wound healing and a lower incidence of wound infections. We analyzed our experience in 2 prospectively enrolled groups of non-randomized patients undergoing elective coronary artery bypass grafting. Group 1 was 81 patients who had endoscopic vein harvesting; group 2 was 80 who had conventional open vein harvesting. The time taken for endoscopic harvest (skin incision to skin closure) was significantly less than that for open harvest (51.07 vs 75.94 min). The number of cases to reach a plateau on the learning curve for endoscopic vein harvest was 20 for 2 lengths of vein and 35 for 3 lengths of vein. Significantly more suture repairs per vein were required in group 1 (1.32) than group 2 (0.38). The incidence of wound infection was 1.2% in group 1 vs 8.8% in group 2. Endoscopic vein harvesting is not difficult to learn and it should be preferred over open vein harvest, given its benefits in wound healing.
|
INTRODUCTION
|
|---|
The era of minimally invasive surgery, which began a couple of decades ago, has extended its influence into cardiac surgery. Apart from minimally invasive coronary artery bypass grafting (CABG) and valve replacements, this concept has also been applied to harvesting the great saphenous vein for use as a conduit in CABG. Since the first description by Lumsden and colleagues in 1994,1 numerous endoscopic and non-endoscopic systems and techniques of minimally invasive vein harvesting have evolved. A recent meta-analysis of these techniques confirmed the benefits of this form of vein harvesting in terms of fewer wound complications.2 Endothelial integrity, function and patency rates are comparable to those obtained by open harvesting.3–5 However, the technical aspects of endoscopic vein harvesting vis-à-vis the conventional open technique have not been addressed exclusively. We analyzed our experience with one of the systems for endoscopic vein harvesting, focusing on the technical aspects, including the learning curve.
|
PATIENTS AND METHODS
|
|---|
This was a prospective non-randomized study undertaken between October 2005 and November 2006. Two groups of patients were identified for comparison from 433 who underwent elective CABG during this period. Group 1 was 81 patients who had endoscopic vein harvesting using the VasoView Uniport Endoscopic Vessel Harvesting System version 6.0 (Guidant Medsystems, Inc., Menlo Park, CA, USA). Informed consent was obtained from all patients specifically for this procedure. Group 2 was 80 patients who underwent conventional open vein harvesting by another member of the surgical team, using longitudinal skin incisions over the leg, with or without skin bridges in between. As the method of vein harvest depended on the operating surgeon, randomization could not be performed. However, the technique of CABG was standardized in both groups. All patients underwent CABG on cardiopulmonary bypass with cold blood cardioplegic arrest. All procedures were performed by a single first-year resident who had carried out approximately 100 open vein harvests before the study, but had no prior experience in endoscopic vein harvesting. Patients with bilateral varicose veins were not considered for any form of great saphenous vein harvesting and received alternative conduits. Two patients who required more than 3 vein grafts were not considered for endoscopic vein harvesting; they underwent conventional vein harvesting and were excluded from the final analysis. There were no other contraindications to endoscopic harvesting. Patients in both groups had their legs prepared in a similar fashion and received the same antibiotic prophylaxis (intravenous cefazolin 1g and ofloxacin 400 mg before skin incision), according to the institutional protocol.
For endoscopic harvesting, the leg was positioned with the hip externally rotated and abducted and the knee flexed, as for conventional open vein harvesting. The vein was exposed through a small horizontal incision in the lower thigh, centered 3–4 finger widths behind the medial condyle of the femur. The vein was consistently located at this point even in obese subjects, obviating the need for preoperative marking of the vein with the help of Doppler ultrasound. After creating a small tunnel around the vein, the telescope with a plastic cone at its tip was introduced through a blunt-tip trocar into the tunnel which was insufflated with CO2 to maintain a pressure of 12–15 mm Hg. The cone tip was used to bluntly separate the vein from the surrounding fat and fascia up to the groin. At this point, the vein was seen to lie within the tunnel and the tributaries were clearly visible. A specially designed cannula with bipolar scissors was used to cut the side branches. A small stab incision was made in the upper thigh to divide the upper end of the vein which was then pulled out through the lower incision. This process was repeated down towards the ankle, depending on the length of vein required. In some patients, the vein was initially exposed below the knee through a horizontal 2.5-cm incision sited at the posterior border of the tibia. Dissection was performed towards the ankle in this situation, and carried upwards until the desired length of vein was obtained. After disconnecting the vein at both ends, it was dilated with heparinized blood at room temperature. All tributaries were ligated and small tears were repaired with 7/0 polypropylene suture. The incisions were closed in layers, without the use of drains, and a compression bandage was applied in all patients. During the procedure, blood gas analysis was performed half hourly and endotracheal CO2 levels were monitored continuously to detect CO2 embolism. For open harvesting, the great saphenous vein was exposed through a vertical incision along the posterior border of the tibia. The vein was bluntly dissected from its surrounding fascia, side branches were ligated and divided, both ends were clipped, and the vein was taken out. The knee joint was not crossed, and additional lengths of vein were taken from the other leg. The vein was prepared as described above, and the wound was closed in 2 layers without a drain. A compression bandage was applied.
Continuous variables are expressed as mean ± standard deviation. Assuming a normal distribution, the 2-tailed unpaired Student’s t test was used to test the null hypothesis for continuous variables. Categorical variables were tested for significance using the chi-squared test. All data were analyzed with the intention-to-treat principle. A value of p < 0.05 was considered significant.
|
RESULTS
|
|---|
The patient characteristics are depicted in Table 1
. There was no significant difference in the number of vein grafts per patient or the mean length of vein harvested in each group (Table 2). The length of the unused portion of vein did not exceed 6 cm in any patient. There were 6 irreparable tears in vein segments from 5 patients in group 1. Two of these patients required additional lengths of vein, which were taken by the conventional method; in the others, the damaged segment was discarded and the remaining vein was sufficient. No other patient required additional lengths of vein. The duration of the procedure was noted from the time of skin incision to skin closure, including the time taken to prepare the vein. Time for closure was not analyzed separately. The mean overall time taken was significantly less in group 1. Subgroup analysis was performed according to the number of vein grafts and the results are shown in Table 3. The time taken for the procedure as our experience progressed is illustrated in Figures 1 and 2. The time taken to harvest 2 lengths of vein fell significantly by the 10th case, and by the 22nd case it has become more or less constant at approximately 30 min. To take 3 lengths of vein, the learning curve is much steeper, the duration falling by 12th case to plateau at around 50 min by the 37th case.
View larger version (8K):
[in this window]
[in a new window]
|
Figure 1. (A) Time to harvest 2 lengths of vein endoscopically; (B) Time to harvest 3 lengths of vein endoscopically.
|
|
View larger version (8K):
[in this window]
[in a new window]
|
Figure 2. (A) Time for open harvest of 2 lengths of vein; (B) Time for open harvest of 3 lengths of vein.
|
|
Endoscopic harvesting had to be abandoned in 15 patients due to inability to identify the vein in 8, vein damage during dissection in 3, a thin vein in a lean patient with minimal subcutaneous tissue, and problems related to the equipment (empty gas cylinder in 1, and light source malfunction in 2). Of these conversions, 7 occurred within the first 40 cases, and 4 in the last 20. There were no cases of CO2 embolism. Wound infection (defined as persistent wound discharge necessitating opening of wound and wet to dry dressings, or a culture-positive wound) was seen in 1 patient in group 1 and in 7 in group 2 (1.2% vs 8.8%). Wound hematoma (n = 1) and ecchymoses of the skin along the vein track (n = 9, 11.11%) were complications seen exclusively in group 1. The patient with hematoma had tense and tender fullness along the leg vein tunnel on the 5th postoperative day. The stab incision used to deliver the vein just above the ankle was opened, and the hematoma was evacuated using sterile suction. A suction drain was left in the tunnel through the same wound for 1 day. One patient in group 1 also developed deep vein thrombosis in the opposite limb, which was not related to vein harvesting. No patient developed cellulitis or seroma. The incidence of myocardial infarction/ischemia (electrocardiogram changes and/or troponin I > 20 ng·mL–1) in the immediate postoperative period was not significantly different between groups (2 vs 1). There was one death in each group: a patient in group 1 had preoperative renal failure, and died from renal failure after CABG; another in group 2 had poor left ventricular function due to an extensive old myocardial infarction, and died from low cardiac output.
|
DISCUSSION
|
|---|
Endoscopic harvesting with the VasoView system definitely has a steep learning curve. None of the published reports have addressed this aspect of the technique. In our experience, 20 to 35 cases are required before a reasonable degree of competency and confidence develops. Difficulty in the early phase is due to 2 factors. First, developing the hand-eye coordination necessary for this procedure takes time, especially as those starting to use the system (residents or physician assistants) seldom have previous experience with minimally invasive surgery. The availability of cadavers or simulators for training in some centers abroad greatly facilitates the process of learning. Second, we feel that identification of the vein through a small incision just adequate to accommodate the blunt-tip trocar is the most important factor in successful endoscopic harvesting. This has been emphasized by others.6 Conversions to the open technique were mostly in cases where identification of the vein was difficult. Routine use of Doppler for preoperative or intraoperative mapping has been described, but availability is an issue that precludes its routine use.7 Mapping techniques are not used in all centers.8 We found that the use of anatomical landmarks was satisfactory, especially as experience increased. Examination of the patient in the standing position preoperatively is useful to locate the vein. However, in patients with excessive subcutaneous fat, extended dissection and a longer skin incision might be required to identify the vein. In such a situation, an adequate seal may not be achieved to insufflate and retain CO2 in the tunnel, thereby making endoscopic dissection difficult; this also predisposes to the formation of seromas.6 Hence it is necessary to locate the vein preoperatively only in obese subjects. Endoscopic harvesting is also difficult in very thin patients with little subcutaneous fat, and in those with thin-walled veins, so it is best avoided in such patients. Once the learning curve is passed, it actually takes significantly less time to perform skin-to-skin endoscopic harvesting than open harvesting. Thus the overall operating time when using endoscopic harvesting is not prolonged. This can be attributed to the longer time taken to close the wound after open harvesting. In the study by Bitondo and colleagues,6 the time taken to deliver the vein was not significantly different between groups, whereas the time taken to close the wound was significantly longer in the conventional group than the endoscopic group.
The major thrust for the use of endoscopic harvesting is its remarkable benefit in leg wound healing. Smaller skin incisions and less trauma to subcutaneous tissue during endoscopic harvesting greatly aid wound healing, which translates into greater patient comfort and early ambulation. It is well established that the traditional method of vein harvest is one of the most consistent predictors of leg wound infection, along with diabetes and obesity.8 Significantly lower wound infection rates of 4%–6.3% in the endoscopic group compared to 14.8%–28.3% in the conventional group have been reported.6,8–10 Endoscopic harvesting confers an 83% reduction in the relative risk of leg wound infection.9 The high prevalence of diabetics in our patient population is one more reason to resort to endoscopic harvesting. The incidence of persistent wound drainage is also significantly lower after endoscopic harvesting.11 The only problem we encountered with endoscopic harvesting, which has not been reported previously, was ecchymoses along part of the dissection site, especially in the groin and above the knee; however, it resolved spontaneously without any sequelae. Some centers routinely use drains, but the efficacy of drains in reducing the incidence of hematoma or ecchymoses has not been addressed in any comparative study thus far.
Although a satisfactory gross quality of the vein was obtained, concern remains regarding the high number of vein repairs in the endoscopic group. In a randomized trial with 100 patients each in endoscopic and open groups, Yun and colleagues12 noted more suture repairs in endoscopically harvested veins (28% vs 5%). Their protocol directed follow-up angiograms that revealed similar graft patency rates in both groups (78.3% vs 82.4% at 6 months for endoscopic and open harvesting, respectively). This suggests that small tears requiring suture repair probably do not influence vein graft patency. Our experience with this technique is very short, and probably with time the rate of repair will reduce. As our study was aimed specifically at the learning curve of endoscopic harvesting, we did not perform any elective angiograms during follow-up. Perrault and colleagues5 carried out quantitative coronary angiography in patients randomized to endoscopic or open harvesting. At a mean of 96 days after surgery, the graft patency rates were similar (14.8% vs 15.6% for open and endoscopic harvesting, respectively). Davis and colleagues13 obtained 95.4% graft patency (determined by electron-beam computed tomography) at 3.74 years with the endoscopic technique, which is comparable to that after CABG with conventional vein harvesting. The basis for similar graft patency rates is related to the difficulty in differentiating veins harvested by either technique grossly, histologically, or functionally. Blinded histologic evaluation has shown no difference in endothelial, smooth muscle, elastic lamina continuity, or medial and adventitial connective tissue.3 Endothelial function assessed by release of and response to vasoactive agents, such as acetylcholine, sodium nitroprusside, nitric oxide, phenylephrine and calcium ionophores, also showed no differences between veins harvested endoscopically or conventionally.4,14,15 In our series, at a median of 3 months with 70% follow-up, there were no deaths in the endoscopic group, and none of the patients had recurrent angina or myocardial infarction.
The other major concern regarding the VasoView system has been CO2 embolism. Lin and colleagues16 reported a 4% incidence of CO2 embolism after endoscopic harvesting. Sudden cardiac arrest has also occurred as a result of this complication.17 Although we did not encounter any clinically significant CO2 embolism, we are aware that it can happen any at time, with potentially fatal consequences. Given the low incidence of clinically important air embolism, we do not routinely use transesophageal echocardiography, as recommended by Lin and colleagues.16
Endoscopic vein harvesting is a feasible and safe procedure. It is not difficult to learn, and can be routinely employed without prolonging operative times. It should be preferred over conventional vein harvesting, given its beneficial effects in leg wound healing.
|
REFERENCES
|
|---|
- Lumsden AB, Eaves FF 3rd, Ofenloch JC, Jordan WD. Subcutaneous, video-assisted saphenous vein harvest: report of the first 30 cases. Cardiovasc Surg 1996;4:771–6.[Medline]
- Athanasiou T, Aziz O, Al-Ruzzeh S, Philippidis P, Jones C, Purkayastha S, et al. Are wound healing disturbances and length of hospital stay reduced wit minimally invasive vein harvest? A meta-analysis. Eur J Cardiothorac Surg 2004;26:1015–26.[Abstract/Free Full Text]
- Griffith GL, Allen KB, Waller BF, Heimansohn DA, Robison RJ, Schier JJ, et al. Endoscopic and traditional saphenous vein harvest: a histologic comparison. Ann Thorac Surg 2000;69:520–3.[Abstract/Free Full Text]
- Black EA, Guzik TJ, West NE, Campbell K, Pillai R, Ratnatunga C, et al. Minimally invasive saphenous vein harvesting: effects on endothelial and smooth muscle function. Ann Thorac Surg 2001;71:1503–7.[Abstract/Free Full Text]
- Perrault LP, Jeanmart H, Bilodeau L, Lesp?rance J, Tanguay JF, Bouchard D, et al. Early quantitative coronary angiography of saphenous vein grafts for coronary artery bypass grafting harvested by means of open versus endoscopic saphenectomy: a prospective randomized trial. J Thorac Cardiovasc Surg 2004;127:1402–7.[Abstract/Free Full Text]
- Bitondo JM, Daggett WM, Torchiana DF, Akins CW, Hilgenberg AD, Vlahakes GJ, et al. Endoscopic versus open saphenous vein harvest: a comparison of postoperative wound complications. Ann Thorac Surg 2002;73:523–8.[Abstract/Free Full Text]
- Allen KB, Shaar CJ. Facile location of the saphenous vein during endoscopic vessel harvesting. Ann Thorac Surg 2000;69:295–7.[Abstract/Free Full Text]
- Crouch JD, O’Hair DP, Keuler JP, Barragry TP, Werner PH, Kleinman LH. Open versus endoscopic saphenous vein harvesting: wound complications and vein quality. Ann Thorac Surg 1999;68:1513–6.[Abstract/Free Full Text]
- Kiaii B, Moon BC, Massel D, Langlois Y, Austin TW, Willoughby A, et al. A prospective randomized trial of endoscopic versus conventional harvesting of the saphenous vein in coronary artery bypass surgery. J Thorac Cardiovasc Surg 2002;123: 204–212.[Abstract/Free Full Text]
- Allen KB, Griffith GL, Heimansohn DA, Robison RJ, Matheny RG, Schier JJ, et al. Endoscopic versus traditional saphenous vein harvesting: a prospective, randomized trial. Ann Thorac Surg 1998;66:26–32.[Abstract/Free Full Text]
- Puskas JD, Wright CE, Miller PK, Anderson TE, Gott JP, Brown WM 3rd, et al. A randomized trial of endoscopic versus open saphenous vein harvest in coronary bypass surgery. Ann Thorac Surg 1999;68:1509–12.[Abstract/Free Full Text]
- Yun KL, Wu Y, Aharonian V, Mansukhani P, Pfeffer TA, Sintek CF, et al. Randomized trial of endoscopic versus open vein harvest for coronary artery bypass grafting: six-month patency rates. J Thorac Cardiovasc Surg 2005;129:496–503.[Abstract/Free Full Text]
- Davis Z, Garber D, Clark S, Roth H, Bufalino V, Budoff MJ, et al. Long-term patency of coronary grafts with endoscopically harvested saphenous veins determined by contrast-enhanced electron beam computed tomography. J Thorac Cardiovasc Surg 2004;127:823–8.[Abstract/Free Full Text]
- Cable DG, Dearani JA, Pfeifer EA, Daly RC, Schaff HV. Minimally invasive saphenous vein harvesting: endothelial integrity and early clinical results. Ann Thorac Surg 1998;66:139–43.[Abstract/Free Full Text]
- Rinia-Feenstra M, Stooker W, de Graaf R, Kloek JJ, Pfaffendorf M, de Mol BA, et al. Functional properties of the saphenous vein harvested by minimally invasive techniques. Ann Thorac Surg 2000;69:1116–20.[Abstract/Free Full Text]
- Lin TY, Chiu KM, Wang MJ, Chu SH. Carbon dioxide embolism during endoscopic saphenous vein harvesting in coronary artery bypass surgery. J Thorac Cardiovasc Surg 2003;126:2011–5.[Abstract/Free Full Text]
- Kypson AP, Greenville NC. Sudden cardiac arrest after coronary artery bypass grafting as a result of massive carbon dioxide embolism. J Thorac Cardiovasc Surg 2005;130:936–7.[Free Full Text]
This article has been cited by other articles:
|
|
|
|
 
J. F. Reed
Leg Wound Infections Following Greater Saphenous Vein Harvesting: Minimally Invasive Vein Harvesting Versus Conventional Vein Harvesting
International Journal of Lower Extremity Wounds,
December 1, 2008;
7(4):
210 - 219.
[Abstract]
[PDF]
|
|
|
TOP
ABSTRACT
INTRODUCTION
