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Endoscopic Closed Tunnel Conduit Harvesting: Tips, Tricks and Traps 91
– Hemopro 2 delivery unit which can be bought
with the company providing the closed tunnel
CO
EVH disposable.
2
– 29 cm length 30-degree telescope.
– Fibreoptic light cable.
– Hemopro 2 black lead for the cauterisation.
This can be sold as part of a EVH disposable
from the EVH company.
– Camera drapes.
– Lens cleaner.
– CO
delivery line with filter.
2
– 20 ml syringe for flushing the vein once
harvested.
– Ioban or plain steridrape for the groin.
Patient Consent and Patient Inform ation
Leaflet:
Informed consent is the process in which a
healthcare professional educates a patient about
the risks, benefits and alternatives of a given
procedure or intervention. The patient must be
competent to make a voluntary decision about
whether to undergo the procedure or intervention
[8]. There are different types of vein harvesting
methods such as open vein harvesting, bridging,
open CO
and closed CO2tunnel endoscopic
2
vein harvesting with their own merits and
drawbacks in relation to postoperative complications. We strongly suggest that providing all
patients who are undergoing endoscopic vein
harvesting with a patient information leaflet will
enhance the process of informed consent and
shared decision making at the preoperative outpatient clinic appointment. It is important for the
reader to obtain local governance and patient
directive group approval before implementing
any patient related leaflets in clinical practice.
Associated Cost and Business Cas e for Setting
Up Endoscopic Vein Harvesting:
Some hospitals do not adopt endoscopic conduit
harvesting technique due to the associated costs
of the disposables which can vary from £600 to
£800 [9–11] depending on volumes of cases per
year. The open vein harvesting has a higher
incidence of wound complications compared to
endoscopic technique [7, 12]. The endoscopic
technique is associated with reduced postoperative pain due to a smaller skin incision compared
to a long scar on the open technique [9]. The
business case should compose of departmental
wound related complications, rationale for
introduction of endoscopic technique, benefits of
endoscopic techniques with patient/staff satisfaction if available, length of hospital stay and
early mobilisation, current literature evidence
and business case proposal. Engaging all relevant
stakeholders (Consultant cardiac surgeons, theatre manager, clinical director, directorate manager, finance officer and patient directive group
member) at an early stage is vital and will support the business case acceptance.
Vein Identification and Incision:
The vein must be identified in three areas for
endoscopic techniques depending upon the
length of vein required. The first incision can be
made 2 cm away and above the medial malleolus
bone for patients who a need lower leg vein. The
second incision can be made on the lateral border
of the tibia and 4 cm below the knee joint for
patients who need a full length of GSV. Please
note through this incision, the vein can be harvested on the lower leg and upper thigh. The foot
end of the table should be lowered during vein
harvesting from the thigh which creates space
and allows handling of the equipment easier.
Incision One:
Creating a skin incision on the lower leg near the
medial malleolus is best for a practitioner who likes
to harvest GSV from the bottom of the operating
table. However, the practitioners need to take
consideration of extending their back, shoulder and
neck for a prolonged length of time which can
causes damage. The benefit of this technique is that
the GSV can be harvested easily because it has less
branches on the lower leg. The main drawback is
that the feet come in the way of the EVH equipments. That can be managed by positioning all
toes and lowering the foot end of the table.
92 B. Krishnamoorthy and J. Blackmore
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Incision Two:
Creating a skin incision at the lateral border of
the tibial bone and 4 cm below the knee joint
allows the practitioner to harvest the vein from
the thigh and lower leg with one single incision.
It is important for the practitioner to stand on the
opposite side when harvesting the vein on the leg
to avoid too much stress on their neck, back and
shoulder. The stalk monitor machine should be
placed diagonally to the operating table on the
foot end to make sure that practitioner feels
comfortable during harvesting. The practitioner
should learn the habit of moving from right to
left when they harvest the right leg above the
thigh (stand on the right side) and lower leg (stand on the left side).
Heparinisation:
Once the vein is identified and dissected, the
heparin should be given systemically by the
anaesthetic team. The dose of heparin depends
on whether the patient had any anticoagulant
prior to surgery. If the patient continued their
anticoagulant until the day of surgery, 2500 units
heparin should be administered and 5000 units
for the patient who have stopped their anticoagulants 7 days prior to the surgery [9]. The reason
for giving systemic heparin prior to the endoscopic technique is to avoid any intraluminal clot
formation inside the GSV which can lead to graft
blockage [13]. It is practitioner’s responsibility to
check the patient notes for anticoagulant administration and confirm this with the patient to
avoid any bleeding complications during harvesting and after harvesting.
Important Tips, Tricks for Harvesting:
– Check the stack monitoring, working condi-
tions, level of CO
cylinder and electric con-
2
nections before scrubbing for the surgery.
Never assume that someone in the team will
check for you.
– White balance the camera, before starting the
case.
– Insert the scope on the warm water before
starting the case to avoid any fog effect. You
can use antifog but better to insert the scope
on the warm water will prevent fogging during dissection.
– Do not screw the dissecting glass cone too
tightly to avoid any breakage and stress on the
tip.
– Place a saline pack with towel under the knee
or medium hard knee support to position the
leg as half positioned frog’s leg which aid in
vein harvesting.
– Please note these are small tricks but the
practitioner needs to adapt their own style of
positioning the patient which is convenient for
them to harvest the GSV.
– Lower the foot end of the leg which will allow
the practitioner to handle the EVH equipments easily without fighting with the foot.
– Dissect the vein anteriorly with the small west
retractor in place and do not dissect the vein
posteriorly or laterally to avoid the vein getting trapped or torn during harvesting by the
insertion port.
– Insertion port should be left without inflation
wherever possible, if needed inject the port
bulb with 5 to 10 ml of air which will reduce
the pressure on the vein.
– Insert the camera scope with dissecting cone
gently:
• Please do anterior dissection for all
patients but for patients who are small built
and tiny leg circumference, do posterior
dissection first (Video 1).
• Once the anterior dissection is completed, do
not bring the dissector back to the start. Do
lateral dissections on either side of the vein
and work backwards to the starting point.
• After successful completion of the anterior
and lateral dissections, please do the posterior dissections of the vein until the end
of the tunnel.
• Please note that the practitioner should do
posterior dissection first, lateral and then
anterior dissection for tiny patient with
small circumference (<7 cm) of the leg.
This creates a space posteriorly, laterally
which allows the vein to fall down and
Endoscopic Closed Tunnel Conduit Harvesting: Tips, Tricks and Traps 93
prevents any vein damage caused by the
EVH equipment.
• While doing dissection, please isolate the
vein branches at least 1 cm around them to
have long length vein branches.
In case, the vein branches have split into
two or shorter branches. Please go around
the branch and divide both branches rather
than dissecting/cutting the shorter length
which cause damage to the Intimal layer.
For shorter and thicker branches which
has less than 1 cm length and more than
1 cm width, the vein branches should be
cut using intermittent Hemopro technique
to avoid any risk of bleeding and thermal
heat damages.
Another important trick to dissection is to
keep the dissecting cone away from the
vein and dissect using the peeling off
technique for thin patients and back and
forth technique for obese patients will
prevent any damage to the patients.
• Cauterisation should be done once the vein
is completely dissection to avoid any small
branch tear.
Remove the tip of the cone from the scope
and add the EVH equipments. Please
make sure that you check that the full
system working before inserting. You can
use wet gauze to check whether the cauterising tip working condition. Insert the
tip of the EVH kit in warm water for a few
seconds to bring it to body temperature.
Insert the unit into the leg and try to avoid
any forceful insertion which can tear the
vein. This happens due to branches or
veins being trapped between the port and
the EVH unit. It is important for the harvester to understand that there is a blind
spot on the EVH unit.
The vein branches should be cut from the
lower end to the thigh rather than pushing
the EVH unit fully to the end. This technique allows the EVH unit to pass
smoothly without tearing any vein
branches.
Once the EVH unit is passed to the targeted end whether it is at the thigh or
lower end of the leg, the branches can be
dissected and cut. Please try not to use the
C-ring wherever possible, if needed please
do not twist the vein with the C-ring.
Twisting the vein with the C-ring can
cause histological level damage to the
vein. The small branches can get torn very
easily from the base of the vein.
• Once the vein is completely mobilised
check with C-hook gently, ligate the distal
and proximal end of the vein with ligaclips
and cut it out or make a small skin incision
on the thigh/lower leg area just above the
vein and locate the vein and dissect it.
• Insert the vessel cannula on the proximal
end of the vein and gently inject heparinised blood, tie all the branches with 4/0
vicryl ties and transfer into the heparinised
blood pot.
• Check for any bleeding in the wound site,
if satisfactory insert a leg drain and do the
normal closure of the incisions with 2/0
vicryl and 3/0 vicryl to the skin.
• Apply small dressing, and pressure bandage from the ankle to the thigh.
Important Traps to Remember While
Harvesting:
Technical Errors:
– Switch off everything and start again.
– Ask the theatre staff to check all the electric
and non-electric connections, sometimes it
gets loosened during connection or
transportation.
– Before using the camera, make sure you have
done the white balance for image clarity.
– Keep a roll under the knee area to lift the
thigh area up and support the knee during
harvesting.
94 B. Krishnamoorthy and J. Blackmore
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– While harvesting thigh, ask the foot end to be
lowered down which allows you to handle the
EVH equipment smoothly without feet getting
in your way.
– While harvesting the lower end of the leg, put
the foot end down and stand on the opposite
side of the harvesting leg which reduces any
stress/injury on your shoulder, back and neck.
Branches:
– Thin patients GSV can be harvested using
EVH but good assessment and ultrasound
scanning need to be done preoperatively by an
experienced practitioner.
– During dissection, the vein needs to be
removed from the skin’s dermal layer very
slowly and gently using the peeling technique
and keep the cone away from the vein as
much as possible (Video 2).
– During cutting and coagulation, the EVH unit
need to be advanced gently by cutting the
dermal layer of the skin to create more space
inside the leg tunnel.
– The vein should be dissected posteriorly and
then anteriorly to give more room for the
EVH unit and to avoid damaging the vein
adventitial layer.
Bleeding: How to Handle or Avoid?
– Dissect the branches carefully especially a
thin hair line branches which can bleed and
obstruct the view.
Video 2 Haemopro dissection of vein side branches (▶ https://doi.org/10.1007/000-a7c)
Endoscopic Closed Tunnel Conduit Harvesting: Tips, Tricks and Traps 95
– Do not dissect or hit any adventitial or cap-
illaries network whilst dissecting because it
can fill up the leg tunnel quickly.
– Primarily cut and coagulate small branches
and cut all the big/thick branches at the end to
avoid any bleeding. Use the intermittent
coagulation technique rather than continuous
which helps to coagulate the vein slowly. For
thicker or bifurcating branches which are
more than 1 cm thicker, use intermittent
coagulation method of 5 s, stop, 5 s, stop and
final 5 s and stop technique.
– If there is any minimal amount of bleeding on
an isolated area:
• Please leave that area for few minutes to
settle and come back to that area for dissection or branch cutting. Sometimes, you
may experience blood clotting or reddish
bruising around that area and if you do,
please ignore and proceed working.
• If the amount of bleeding is larger, you can
remove the full EVH kit and squeeze the
blood out from the tunnel and leave it for a
couple of minutes to settle. If it is larger
and you are unable to stop it, it is better to
convert to bridging technique or put pressure on that area to stop the bleeding.
• Major bleeding can be avoided by cutting
the thicker/larger branches at the end of the
vein harvesting procedure. Make sure you
check that the full vein is harvested, and all
small branches and surrounding tissues are
removed and then cut the larger branches
before disconnecting the vein.
– Try and avoid injecting any saline to clear the
lens if possible because this fills up the leg
tunnel. Always try to touch the wall of the leg
tunnel to clear your lens.
Vein Damage: How to Avoid It?
– During learning, it is possible to tear the vein
or cut the vein into two pieces. It is important
to take it slowly as a step by step harvesting
method rather than trying to do everything
together.
– Vein can get damaged by the tip of the cone
which can lead to carbon dioxide embolism.
To avoid:
• Always make sure that your dissecting
cone on the middle of the screen during
dissection and try to keep the cone away
from the vein. Important tip to dissection
of the vein is to take vein with surrounding
tissues which will avoid any tears or holes
on the vein.
• Set the carbon dioxide level minimum of
10 mmHg with 1-3 L flow to avoid drying
the adventitial layer of the vein. 1 L for
thin legs and 2-3 L for obese patients.
Obese Patients:
– Scan the leg pre-surgery and mark where your
skin incision is and measure the depth of the
vein which will help you to find the vein.
– If it is very hard to find the vein if the depth of
the vein is above 1 cm. You can use the cone
dissector to search for the vein which avoids
making pockets or rough dissection.
– Make the skin incision smaller than 2 cm will
allow you to keep the insertion port in place
with minimal air in the balloon.
– Set the gas flow to 12 mmHg and 3 L rate
which will help the fat tissues away. Make
sure that you do not create any pockets or
distort the fat tissues during dissection.
96 B. Krishnamoorthy and J. Blackmore
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Vein with surrounding tissues.
C- hook
Vein
Vein surrounded
with fat tissues.
Tunnel inside the leg
Conclusion:
Endoscopic vein harvesting is an art and the
practitioner needs to be trai ned step by step by
the structured training method to obtain the best
quality vein for the coronary artery bypass
grafting. We strongly believe that nothing is
impossible, but we need careful assessment and
patient selection which will avoid major problems during vein harvesting. Support mechanisms with clear guidance need to be in place to
tackle difficult patients such as obese, thin and
patients with segments of varicose veins. The
EVH trainees need to be given the chance to
learn on patients with no additional comorbidities for vein harvesting.
4 Endoscopic Radial Artery
Harvesting
Historical Context:
The radial artery (RA) was first used as a conduit
for coronary artery bypass graft surgery (CABG)
in 1971 by Carpentier and colleagues [14]. Use
of the RA was abandoned in 1973 due to higher
occlusion rates than the saphenous vein. Poor
patency rates were attributed to graft spasm,
severe intimal hyperplasia due to harvesting
technique (skeletonization), and mechanical
dilation [15]. A patent RA graft was discovered
15 years after it was previously thought to be
Endoscopic Closed Tunnel Conduit Harvesting: Tips, Tricks and Traps 97
occluded, leading to the revitalization of using
the RA as a conduit in CABG [16]. Acar et al.
[16], published results in 1992 showing 100%
early patency rates of radial artery conduits.
Three changes were made at that time including
harvesting the radial artery as a pedicle, rather
than skeletonization, replacing mechanical dilation with pharmaceutical dilation, and adding
postprocedural vasodilator therapy with a calcium channel blocker or nitrate. RA use continues to be promoted in recent years with trusted
evidence suggesting higher patency rates and
survival benefit[17, 18].
Radial Artery Anatomy:
The brachial artery traverses distally through the
upper arm until it’s bifurcation into the radial and
ulnar arteries within the cubital fossa. The RA
continues in the lateral aspect of the forearm,
while the ulnar continues medially. The RA lies
between the flexor carpi radialis and brachioradialis muscles. As the RA continues distally, it
becomes more superficial until it can be palpated
just laterally to the tendon of the flexor carpi
radialis muscle. As the RA approaches the wrist,
it bifurcates into deep and superficial branches
that proceed to anastomose with the branches of
the ulnar artery forming the deep and superficial
palmar arches. The first branch of the RA is the
radial recurrent artery which has a lateral takeoff
just distal to the origin of the RA [19]. The RA is
responsible for blood supply to the posterolateral
muscles of the forearm, elbow joint, carpal
bones, thumb and lateral index finger. The
superficial radial nerve traverses along the RA,
deep to the brachioradialis muscle, then over the
distal radius and radial fossa. The superficial
radial nerve provides sensory innervation to the
thumb, index, middle, and lateral half of the ring
fingers in addition to the dorsal hand area of
those fingers [20].
Endoscopic Radial Artery Harvest (ERAH)
Indications:
The RA should be considered for use in CABG
when the coronary angiogram displays stenoses
of >70% within the left anterior descending and
left circumflex systems and >90% within the
right coronary artery system (Fig. 5) for coronaries perfusing the LV myocardium [21].
The RA has been shown to have superior surgical outcomes to the saphenous vein (SV) and
comparable surgical outcomes to the right internal thoracic artery (RITA) (while having a lower
incidence of deep sternal wound infection),
therefore it shoul d be the second conduit of
choice behind the left internal thoracic artery
(LITA) [22–24]. The patient should be less than
75 years old as this has been shown to be the
cutoff for loss of benefit for RA use [18].
Contraindications:
Contraindications for RA harvest include recent
catheterization, Raynaud’s disease, rheumatoid
arthritis, scleroderma, subclavian stenosis, renal
failure requiring hemodialysis (need for AV fistula), and poor forearm or hand collateral circulation [25]. Dupuytren’s contracture was listed in
this cited publication as a contr aindication,
however it is this author’s opinion that Dupuytren’s is not of vascular origin and neither its
existing condition nor eventual repair would be
affected by harvesting the RA. Additionally,
carpal tunnel syndrome (CPS) was also listed in
this reference as a contraindication, but in our
experience, we have found that patients with
surgically treated CPS can safely undergo RA
harvest without complication.
Preoperative Planning
Collateral Circulation of the Hand:
The RA is predominantly responsible for blood
supply to the thumb and radial side of the index
finger [26]. The radial and ulnar arteries feed into
the hand, forming superficial and deep palmar
arches. A complete superficial palmar arch in
which the ulnar artery is dominant and can adequately perfuse the entire hand is found in 84.4%
of the population [27]. A combination of noninvasive techniques form the modified Allen’s
Test which can accurately determine the completeness of the palmar arch. This is performed
98 B. Krishnamoorthy and J. Blackmore
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Fig. 5 Coronary artery angiogram displays stenoses >90% in the right coronary artery system
by applying a continuous pulse oximeter/
plethysmometer on the thumb. Once a baseline
waveform amplitude and oxygen saturation are
established, the radial and ulnar arteries are
compressed while the patient is asked to clinch
their fist. When the waveform amplitude has
flattened and the oxygen saturation has diminished, the patient opens and relaxes their hand
while the ulnar artery compression is lifted.
The RA rema ins occluded by compression currently. Return of the pulse waveform to 50%
amplitude or greater and baseline oxygen
saturation is considered a negative test indicating
the RA can be safely harvested without concern
for hand ischemia.
Ultrasound:
Ultrasound (US) should be utilized preoperatively on every RA harvest case. The RA can be
easily identified with the venae comitantes and
visible pulsations. Measureme nts can be made
quickly and accurately via US with the target
diameter greater than 2 mm. The US can also be
used to follow the length of the artery to evaluate
Endoscopic Closed Tunnel Conduit Harvesting: Tips, Tricks and Traps 99
Radial artery
Fig. 6 Illustrates the ultrasound image of the radial artery
for any anatomical anomalies or intraluminal
plaques (Fig. 6).
Surgical Steps:
Routine Setup:
Two arm boards are attached to the bed, and the
arm is laid out to an angle slightly less 90°. If
using a tourniquet; a non-sterile webril and
tourniquet are placed on the upper arm. With a
permanent marker, draw a line two finger widths
below the antecu bital fossa to demarcate the
proximal limit of dissection. Draw a line on the
wrist crease to demarcate the distal limit of dissection. Circumferentially prep from fingertips to
the tourniquet per hospital protocol. After prep,
exclude the non-sterile tourniquet with two 1010
drapes. The arm boards are then draped with a
sterile Mayo stand cover. The arm is placed
down with a rolled towel under the wrist (Fig. 7)
to extend the incision sit.
Heparinization: Preoperative heparinization
is initiated depending on surgeon preference.
Tourniquet Use:
A common debate within the RA harvesting
community is whether or not to use a tourniquet
for the procedure. The RA and its branches are
significantly more delicate than that of the SV
and the harvesting tunnel is often smaller than
what is found in the leg. The use of a tourniquet
ensures a bloodless field providing the best
environment for precise dissection and cauterization of the branches and connective tissue.
Often the argument is made to have the tourniquet in place and deflated, only to be inflated if
significant bleeding is encountered. This scenario
place’s reliability on OR staff to quickly inflate
the tourniquet and leaves a bloody environment
in which additional harvesting would be more
challenging due to compromised visualization.
Use of the tourniquet is not without risk. Potential complications include nerve injury (1:6200
for upper limb), muscle injury, vascular injury,
skin injury. The most common side effect seen
with upper extremity tourniquet use is sudden
decrease in CVP and MAP due a combination of
the release of anaerobic metabolites into the
systemic circulation and shif t in blood volume
back into the extremity. For this reason, it is
important to communicate with your anesthesia
provider about the tourniquet deflation. One to
three hours has been described as a safe time
100 B. Krishnamoorthy and J. Blackmore
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Fig. 7 Illustrates the hand position and setup before harvesting radial artery
limit for tourniquet use, however, with this procedure, no more than one hour should be needed
nor exceeded [28].
Vasodilators:
Preoperative initiation of a vasodilator can aid in
avoiding spasm of the RA. A nicardipine or
diltiazem drip is started prior to incision at a
modest rate of 2.5 mg/hr as tolerated by the
patient’s hemodynamics. The vasodilator drip is
continued postoperatively until a PO calcium
channel blocker can be started. Our practice
prefers starting Amlodipine at 2.5 mg PO on
postop day 1 with a 2 h overlap of the IV infusion prior to cessation. The calcium channel
blocker is continued postoperat ively for three
months to one year, depending on institutional
preference and patient tolerance [29].
Closed Tunnel Harvesting Technique:
Dissection:
An approximately 3 cm longitudinal incision is
made over the RA just lateral to the tendon of the
flexor carpi radialis muscle. A thin layer of adipose tissue will be dissected away to reveal the
fascia (Fig. 8) covering the RA. The fascia can be
cut away with Jameson scissors revealing the RA
and satellite veins. There are numerous vascular
branches in this area requiring delicate and precise ligation to avoid bleeding. Small clips are
adequate to aid in the ligation of the branches;
however, an ultrasonic scalpel is preferred for
increased efficiency. Once the RA and accompanying veins are isolated, a vessel loop is passed (Fig. 9) under the pedicle. A soft bulldog
clamp is applied to the RA and the modified
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