June 23, 2001
Background.
Harvesting the great saphenous vein for coronary artery bypass grafting is often associated with complications in wound healing, insufficient cosmetic results, and delay in mobilization of the patients. The aim of this study was to compare the results of our minimally invasive technique with the traditional method.
Methods. We report our experience of minimally invasive direct vision harvesting the great saphenous vein with the Aesculap retractor system (Aesculap AG Co KG, Tutlingen, Germany) by performing 3 (to 5) small cutaneous incisions. We scheduled 255 patients for elective coronary artery bypass grafting prospectively randomized to undergo vein harvesting by either the minimally invasive technique (group A: n = 128; age range, 68.2 ± 9.1 years; male, 53.1%) or by the traditional technique (group B; n = 127; age range, 66.1 ± 8.3 years; male, 62.9%). We classified and defined leg-wound healing disorders in terms of mild, moderate, and severe wound-healing disturbances.
Results. Between group A and B there were no differences with the risk stratification before operation, length of vein being harvested, or total operation time. The time for minimally invasive harvesting of the great saphenous vein was slightly increased. Severe leg-wound healing disorders occurred in 4 of 128 patients of group A (3.1%) versus 12 of 127 patients of group B (9.4%) with significant difference (p = 0.042).
Conclusions. Minimally invasive direct vision harvesting the great saphenous vein is an attractive alternative to the traditional open-harvesting technique. In our trial this procedure resulted in fewer wound complications and showed a much better cosmetic outcome. The total operation time was not increased by using the minimally invasive technique.
Introduction
Coronary artery bypass grafting (CABG) is the most common procedure
performed in adult cardiovascular operations. Despite the increased
use of arterial grafts, the most frequently used conduit is
the greater saphenous vein for coronary revascularization since
its introduction in 1967. The long, continuous incision is the
traditional standard technique for harvesting the greater saphenous
vein for CABG. When using the traditional open technique,
wound-healing disorders are common and have been reported to occur in 1.5%
to 24% of patients [
1–
4]. The prevalence
of wound-healing disturbances varies widely
[5] and depends to some degree on
the definition of these disturbances, as well as on the intensity
of follow-up examinations. Most studies have shown that the
mean time to diagnosis is about 2 weeks after operation
[5].
Large numbers of patients with leg-wound complications are treated on an outpatient basis with antibiotics and by visiting nurses. Some of them have a prolonged hospital stay or require readmission for intravenous antibiotics and secondary surgical treatment with debridement, both of which increase hospital costs.
Minimally invasive vein-harvesting studies have been shown to
be effective in decreasing
leg-wound disturbances, which results
in less postoperative pain and superior cosmetic results [
6–
8].
The aim of this prospective, randomized study was to document the prevalence of leg-wound disturbances in two groups of patients who had undergone traditional open or minimally invasive saphenous vein harvesting for CABG.
Material and methods
A total of 255 patients undergoing elective CABG at the Deutsches
Herzzentrum Berlin (Berlin, Germany) with use of the great saphenous
vein were prospectively randomized using
a computer-assisted procedure dividing them into two groups through
follow-up. The
study was comprised of patients with multivessel disease, normal
or nearly normal cardiac function, and the same preoperative
risk stratification. One hundred
and twenty-eight patients underwent
the
minimally invasive vein harvest (MIVH) procedure (group
A: age range, 68.2 ± 9.1 years; male, 53.1%; female,
46.9%), whereas another 127 patients underwent the traditional
vein harvest procedure (group B: age range, 66.1 ± 8.3
years; male, 62.9%; female, 37.1%). Both groups were demographically
similar
(Table 1).
Table 1. Preoperative Demographics
Characteristic | Group A (n = 128) | Group B (n = 127) | p Valuea | | Age (years) | 68.2 ± 9.1 | 66.1 ± 8.3 | 0.121 | Male | 68 (53.1%) | 80 (62.9%) |
| Female | 60 (46.9%) | 47 (37.1%) | 0.98 | | | |
| Risk stratification | | | | Diabetes mellitus | 73 (57.0%) | 67 (52.7%) | 0.848 | Obesityb | 38 (29.7%) | 42 (33.1%) | 0.377 | Hypertension | 115 (89.8%) | 109 (85.8%) | 0.864 | Peripheral vascular disease | 41 (32.0%) | 49 (38.6%) | 0.170 | Renal failurec | 66 (51.6%) | 52 (40.9%) | 0.261 | Chronic use of steroids | 39 (30.4%) | 44 (34.6%) | 0.583 | Left ventricular ejection fraction | 55.6 ± 11.6 | 55.3 ± 11.6 | 0.875 | |
a Statistical significance was determined using cross tables and Pearson c2.
b Obesity 30% of normal weight (Broca Index).
c Preoperative serum creatinine 2.0 mg/dL.
Exclusion criteria included emergency surgery, low cardiac function (left ventricular ejection fraction < .40), conversion from the MIVH to the open technique during the operation, harvesting of the vein from both legs, and the presence of leg decubitus ulceration or an active bacterial infection, or both.
The variables that were analyzed included intraoperative time for vein harvesting, number of bypass grafts, total operation time, length of intensive care unit and total hospital stay, risk factors for wound complication (age, sex, diabetes, obesity, peripheral arterial disease, renal failure, chronic use of steroids, left ventricular ejection fraction), and the postoperative grading of leg-wound complications. The incidences of leg-wound complications were assessed during the follow-up period of at least 2 weeks of postoperative hospital stay for all patients in this trial. The wound-healing disturbances were classified and defined as either mild or moderate (without prolonged hospital stay or secondary surgical treatment) or severe (with prolonged hospital stay or secondary surgical treatment). Follow-up examination was carried out in all patients in both groups.
Assessment of wound-healing disturbancesWound-healing disturbances were defined as edema and erythema,
incisional pain with inflammation, wound dehiscence, hematoma,
skin or fat necrosis, dermatitis, cellulitis, lymphangitis,
and infection with purulent drainage. We defined these complications
as mild, moderate, or severe
wound-healing disturbances
(Table 2) and classified the disturbances found in our patients accordingly.
Leg wounds were assessed daily by independent research doctors
and nurses.
Table 2. Grading for Leg-Wound Healing Disturbances After Removal of the Greater Saphenous Vein
Mild | Moderate | Severe | | Erythema | Incisional pain with inflammation | Wound dehiscence ( 1 cm) | Mild wound tension | Severe wound tension without wound dehiscence | Breakdown of wound | Mild wound secretion | | Infection with purulent drainage | Mild edema at the wound edge | Local wound dehiscence ( 1 cm) | Lymphangitis | Local skin necrosis (< 1 cm) | More than one local skin necrosis | Distinctive hematoma | Local incisional pain without inflammation | Hematoma with wound tension but without infection | Distinctive skin or fat necrosis, or both | Mild hematoma on the surface | Cellulitis (mild) | | | | Disturbances without prolonged hospital stay or secondary surgical treatment | Disturbances with prolonged hospital stay, intravenous antibiotics or secondary surgical treatment, or both | |
Surgical protocol of vein harvesting
Variables in surgical technique included the level of experience of the person harvesting the vein, the type of closure (subcuticular closure) and the creation of a flap during harvesting. Cefazolin was used for antibiotic prophylaxis for 48 hours.
Traditional longitudinal vein harvesting
The patient was positioned on the table for CABG with standard preparation and drapes. The traditional technique involves an incision that begins at the ankle, without skin bridges, and ends at the inguinal crease or midthigh region. After removal and preparation of the vein, hemostasis was achieved by the use of electrocautery. In all patients drainage tubes were inserted in the thigh region for at least 24 hours. The use of one or two layers of running 2−0 Vicryl sutures (Ethicon, Somerville, NJ) closed the wound before or during cardiopulmonary bypass. The skin was closed with a continuous 3−0 Vicryl intracuticular suture. Finally, the leg was wrapped with an elastic bandage for 48 hours.
Minimally invasive vein harvestingThe patient was positioned on the table for CABG with standard
preparation and drapes. A 2 cm skin incision was made at the
medial aspect of the knee and the greater saphenous vein was
identified. Great care was taken to remain directly anterior
to the vein to aid visualization and to avoid undermining the
surrounding subcutaneous tissue. The Aesculap retractor (Aesculap
AG Co KG, Tutlingen, Germany) was inserted anterior to the vein
and used to create a tunnel
(Fig 1). The device is composed
of a blade (various lengths up to 18 cm) coupled with a light
source, and it allows dissection of the vein under direct vision
of the surgeon. Vessel loops were used for traction, and branches
were clipped under direct vision. The next skin incision, also
2 cm in length, was made in the midthigh region. Again the vein
was identified and the retractor was inserted to connect the
tunnels and to complete the inferior dissection. Finally, the
last incision was made approximately 3 to 4 cm distally to the
inguinal crease, and the greater saphenous vein was identified
and dissected in the same procedure to connect the tunnels.
The 2 cm skin incisions were approximately 12 to 18 cm apart.
If necessary, if more vein segments were needed, the other extremity
could be used or the next incision could be done on the lower
leg to advance the tunnel from the knee region to the lower
leg up to the groin area. Proximally and distally the vein was
clipped under direct vision. After removal and preparation of
the vein, hemostasis was performed by the use of electrocautery.
The drainage tubes were inserted in the tunnel for at least
24 hours in all patients. The wounds were closed by the use
of one or two layers of running 2−0 Vicryl sutures and the skin
with continuous intracuticular sutures that used 3−0 Vicryl
before systemic heparinization and cardiopulmonary bypass were
undertaken
(Fig 2). The leg was wrapped with an elastic bandage
for 48 hours.
Statistical analysis
Statistical significance between the groups was established using the t-test for equality of means, Levene’s test for equality of variances, and cross-tables and 2 tests by the use of SPSS software (SPSS Inc, Chicago, IL).
Results
A total of 255 patients who underwent elective coronary artery
bypass with use of the great saphenous vein at our institution
were followed-up for at least 2 weeks until their hospital release.
Both groups were demographically similar. There were no statistical
differences
(Table 3) between the time of vein harvesting (p
= 0.15), the number of bypass grafts (p = 0.239), the total
operation time (p = 0.995), the length of intensive care unit
stay (p = 0.454), or risk factors for wound complications (age,
sex, diabetes, obesity, peripheral arterial disease, renal failure,
chronic use of steroids, left ventricular ejection fraction).
The mean age was 68.2 years in group A and 66.1 years in the
patients who underwent the open technique of vein harvesting
(p = 0.121). Male patients dominated in both groups. The mean
length of the removed vein was 42.7 cm in the MIVH group and
41.8 cm in the group that had the open technique (p = 0.325).
The average harvesting time, calculated from leg incision to
wound closure, was 43.2 minutes in the MIVH group and 41.8 minutes
in the open technique group (p = 0.15). The MIVH technique always
used the upper leg vein but frequently extended to below the
knee (in 27 cases).
Fifty-one of the 127 saphenous veins harvested
using the open technique (40.2%) were lower leg veins.
Table 3. Operative Variablesa
Variable | Group A (n = 128) | Group B (n = 127) | p Valueb | | Vein harvested (cm) | 42.7 ± 6.20 | 41.8 ± 5.90 | 0.325 | Number of bypass grafts | 2.2 ± 0.60 | 2.0 ± 0.50 | 0.239 | Harvest time (min) | 43.2 ± 18.8 | 41.8 ± 13.4 | 0.150 | Total operation time (min) | 228.6 ± 60.4 | 228.7 ± 62.4 | 0.995 | Postoperative intensive care unit time (h) | 26.3 ± 21.3 | 28.9 ± 22.9 | 0.454 | Type of operation | | | | Coronary artery bypass grafting (n) | 121 (94.5%) | 115 (90.5%) | 0.711 | Aortic valve replacement and coronary artery bypass grafting (n) | 7 (5.50%) | 12 (9.50%) | | |
a All data are represented as mean ± standard error mean.
b Statistical significance was determined using cross tables and Student’s t test.
There was no clinical evidence for acute graft closure in either group; ie, there were no significant changes in electrocardiography or cardiac enzymes in the follow-up period.
Severe
wound-healing disturbances occurred in 3.1% of patients
who had MIVH (4 of 128) versus 9.4% of patients who had the
traditional longitudinal incision (12 of 127). Mild or moderate
wound healing disturbances occurred in 5.4% of patients who
had MIVH (7 of 128) versus 11% with the open technique (14 of
127). All patients with severe
wound-healing disorders required
a prolonged hospital stay (average, 26 postoperative days) and
intravenous antibiotics. Five patients from group
B had leg-wound complications that required secondary surgical treatment with
debridement after wound dehiscence with flap necrosis or purulent
infection. Two of these 5 patients required more than one secondary
surgical treatment. All other
wound-healing disturbances were
treated by conservative methods such as the use of topical solutions
or intravenous antibiotics. The exact nature
of all wound-healing disturbances in both groups is shown in
Table 4.
Table 4. Wound-Healing Disturbances in Each Group After Removal of the Saphenous Vein
Group A (n = 128) | Group B (n = 127) | | Mild/moderate | | Mild/moderate | | | | | | 3 | Mild wound secretion without infection | Thigh region | 4 | Mild wound secretion without infection | Lower leg | | | | | 2 | Local wound dehiscence | Thigh region | 2 | Mild wound secretion without infection | Thigh region | | | | | 2 | Hematoma with wound tension | Thigh region | 2 | Incisional pain with inflammation | Thigh region | | | | | | | | 3 | Local wound dehiscence | Lower leg | | | | | | | | 2 | Hematoma with wound tension | Thigh region | | | | | | | | 1 | Erythema | Thigh and lower leg | | | | | Severe | | | Severe | | | | | | | 2 | Distinctive skin necrosis | Lower leg | 3 | Distinctive skin and flap necrosis | Lower leg | | | | | 1 | Separation of wound | Thigh region | 3 | Distinctive skin and flap necrosis with secondary surgical treatment | Thigh region | | | | | 1 | Infection of wound | Thigh region | 2 | Wound dehiscence | Lower leg | | | | | | | | 1 | Breakdown of wound | Lower leg | | | | | | | | 1 | Breakdown of wound | Thigh region | | | | | | | | 1 | Infection with purulent drainage with secondary surgical treatment | Thigh region | | | | | | | | 1 | Infection with purulent drainage with secondary surgical treatment | Lower leg | | | | | |
Comment
Leg-wound complications after CABG are an underestimated source
of patient morbidity. The traditional open technique is often
associated with complications in wound healing, insufficient
cosmetic results, and delays in mobilization of the patients,
but it is rapid and provides optimal visualization of the saphenous
vein during harvest. The traditional open technique is
invasive, requiring a large incision and a longer period for wound closure,
with a larger scar. Complication rates from saphenous vein harvesting
vary widely in vein harvesting studies, depending on the definition
of wound-healing disturbances and the intensity
of follow-up procedures. Previous reports observed morbidity rates ranging
from 13% to 24% [
1–
5,
9]. Clearly they can be a source
of increased length of hospital stay (thus increased costs)
and extremity pain with discomfort.
Studies of different
minimally invasive vein harvesting techniques
have shown a decreased
leg-wound complication rate, lower extremity
pain, shorter hospital stay because of quicker mobilization,
better cosmetic results, and an overall improved level of patient
satisfaction [
6–
8,
10,
12]. Most of these studies demonstrated
a significantly lower
rate of leg-wound complications compared
with the traditional technique [
10–
13].
Our incidence
of leg-wound complications and the associated
risk factors noted in this study are in agreement with those
of other studies. In our trial we observed severe
leg-wound complications in 3.1% of patients who had
minimally invasive vein harvesting versus 9.4% of patients who had traditional
open technique vein harvesting. We saw no differences between
the groups regarding risk stratification, but all severe complications
occurred in patients with peripheral vascular diseases or diabetics.
The prevalence and severity
of wound-healing complications correlated
with the presence of diabetes, obesity, and peripheral vascular
disease, as shown by other studies in the past [
4,
5,
9]. All
patients with severe wound complications had a prolonged hospital
stay (average, 26 days), with correspondingly higher costs,
which, however, were not exactly measured. In the group with
traditional open vein harvesting, the majority
of leg-wound complications (7 of 12) occurred in the lower leg
[12] because
of the lower vascularity in patients with peripheral vascular
disease and diabetics. In our trial, the harvesting of the vein
in the
minimally invasive procedure was done mainly from the
upper leg; we extended the harvesting to the lower leg only
in 27 of 128 patients. In the traditional procedure we used
the lower leg vein in addition to the thigh vein in 51 of 127
patients. The risk stratification
for wound-healing disturbances
was similar in both groups. Therefore we assume that there
were more wound-healing disturbances in the traditional group because
of this fact.
Most of the wound-healing problems occurred on
about the seventh postoperative day in both groups. Severe wound
complications occurred especially after the creation of flaps
and extensive use of electrocautery near the skin, and therefore,
the outcome was not insignificantly dependent on the surgical
technique and care. Compared with the reported complication
rate of 2% to 4% [
8,
10,
11] for patients who had undergone
different
minimally invasive vein harvesting procedures,
our leg-wound complication rate was acceptable.
The problem of wound cosmetics was greatly improved because the patients who had the minimally invasive approach were more than satisfied with the cosmetic result postoperatively, whereas not all of those in the traditional group were satisfied. The same was observed with the problem of postoperative pain in the leg from which the vein was removed. Most of the patients with the minimally invasive approach had no problems with mobilization because of pain or tension, but patients who had the traditional approach complained mostly of extensive pain or tension on mobilization of the leg. These problems were assessed by observations of the doctors.
We hypothesize that our MIVH technique and several others maintain
improved vascularity to superficial tissues and reduce the development
of complications because of small skin incisions, creation of
a subcutaneous tunnel along the vein, and only slight surgical
injuries of the tissue. This prospective, randomized trial demonstrated
that factors including patient satisfaction, reduced wound complications,
and reduced harvesting time justify a
minimally invasive approach
for vein harvesting in the future.
Minimally invasive techniques
to harvest the saphenous vein have improved and evolved by using
common instruments, such as a simple retractor
[7], a lighted
retractor
[13], or other new tunneling instruments besides commercially
available,
minimally invasive endoscopic instruments [
2,
5,
6,
14]. We chose a lighted retractor after testing several systems
because of its relatively low costs and simple technique. Our
technique described here provides good exposure and light within
the tunnel and is easily learned. The equipment is reusable,
inexpensive, and readily available. Before this technique was
used, the main argument against this approach was the risk of
excessive vein handling and damage. There were no surgical injuries
to the vein or avulsed branches because of removal under direct
vision. A number of studies have shown that the immediate postharvested
vein pathology using the
minimally invasive technique was no
different from the traditional method [
15–
17]. Although
we did not send the vein graft for pathologic examination, we
did see the same vein quality from the clinical results.
Few studies have been performed prospectively [
9,
11] to evaluate
complications of saphenous vein harvesting for CABG. Therefore,
we performed our trial prospectively and with randomization
to compare two techniques of harvesting the saphenous vein in
two patient groups with the same risk profile.
In conclusion, from our experience, it is possible to harvest an equal length of vein and an equal quality of vein in a slightly longer time using the minimally invasive direct vision approach. This is an attractive, practicable, and safe method, which can be easily performed after a short learning period without compromising the aortocoronary bypass procedure. The cosmetic results are excellent with a tremendously positive response from the patients. The modified, minimally invasive vein harvest method is a relatively new method, and long-term patency rates need time to be proved. Our trial compared two different approaches to vein harvesting for CABG and showed a lower percentage of wound complications in the minimally invasive group.
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