Keywords
ESRD - hemodialysis - arteriovenous fistula - chronic kidney disease - minimal access
surgery - vascular access
Introduction
Arteriovenous fistula (AVF) is a life-saving procedure for long-term survival of patients
with chronic kidney disease.[1]
[2]
[3]
[4] Today minimal access surgery (MAS), with advantages of quick recovery, reduction
in pain, bleeding, and hospitalization, is at the forefront of surgical advances.
Can we then create an AVF through a 0.5, 1.0, or a 1.5 cm skin incision approach?
If so, how? With vascular clamps occupying certain space, such a possibility would
be unthinkable. Here a very simple innovative idea is presented that creates an AVF
through minimal access without using vascular clamps.
Material and Method
From 1998 to 2019, 622 AVFs were created without using a vascular clamp, by an innovative
concept presented here, in an age group ranging from 15 to 82 years. Male to female
ratio in this group was ~2:1.
Zeiss OPMI II or Leica microscope was used to develop the technique, with 33 cases
operated with 0.5 cm skin incision; later, most of the cases were done with a Zeiss
ophthalmic loupe with 4x magnification, with 288 cases within 1 cm and 215 cases within
1.5 cm skin incision approach, at distal forearm, including 3 cases of ulnar AVF.
The series also includes 57 cases of AVF done at the elbow.
The Method
The first method involved side-to-side radial artery cephalic vein AVF creation[5] through a minimal access approach without using vascular clamps.
A skin incision is taken at a suitable site, proximal to the wrist between radial
artery and cephalic vein, where they are closest to each other. Color Doppler is used
to choose the site when the vein is not visible or palpable and collapsible. After
the dermis is cut, a segment of cephalic vein is isolated with a small blunt tip scissor
and a fine tip bipolar cautery. While preserving the radial cutaneous nerve, a buttonhole
is created into the soft tissue below the vein and a vascular loop is passed around
to bring the segment of the vein toward the incision, excess soft tissue is stripped
off, and tributaries if any are cauterized or ligated and divided. Then the skin opening
is shifted medially over the position of the radial artery, and the soft tissue is
cleared till the deep fascia. Next, a small pinch of deep fascia over the radial artery
is elevated and snipped to create an opening in the deep fascia. The artery is then
separated and protected while the deep fascia is divided under vision by exposing
it with a small right-angle retractor pulling the corner of the skin incision proximally
or distally as needed. This prevents kink and compression by the edge of the deep
fascia when the artery is elevated from its bed. With a blunt round tip dissecting
scissor, the radial artery is separated from its venae comitantes, and after ligating
or cauterizing any fine branches excess adventitia is removed. Now, there are two
ways of preparing for an AVF without using a vascular clamp: one with “forceps,” and
the other with an “AVF platform”—a simple device designed by the author, which is
a long and flat device, slightly curved on the flat surface from side to side, with
round borders, with narrow tapering rounded tip at one end that broadens gradually
going toward the other end ([Fig. 1]). In “forceps technique,” both the prongs of the forceps are inserted under the
freed segment of the radial artery and then the freed segment of cephalic vein is
brought over them with the help of the vascular loop; the tips of the prongs are brought
out of the incision and rest across the incision. Then a needle cap is inserted between
the two prongs of the forceps and slid backward toward the fulcrum to widen the gap
between its two prongs till the vessels are sandwiched gently but adequately between
the outer surface of the forceps prong and the soft tissue around it, occluding the
vessels ([Fig. 2]). In the other technique, the narrow blunt rounded end of the AVF platform is pushed
under the freed arterial segment and the venous segment is brought over it with the
help of the vascular loop. Then the tip of the AVF platform is brought out on the
other side of the incision to rest across the incision. It is then gradually pushed
forward till the arterial and venous segments get gently sandwiched between the soft
tissue and the broader rounded edges of the AVF platform to block the lumen to prevent
any blood flow with optimal pressure. The artery and vein segments thus brought out
of the incision are now lying side by side abutting each other. The arterial and venous
segments are then carefully stripped off of excess loose adventitia. Two well-matched,
parallel venotomy and arteriotomy, of anywhere between 5 and 10 mm length, are created.
One notices that as the walls of the artery and vein lie abutting each other, the
inner cut edges are in end-to-end contact, which makes suturing easy. The side-to-side
anastomosis is created with 7–0 Prolene sutures ([Fig. 3]). After starting at one corner, care is taken that the second and the subsequent
continuous stitches over the posterior wall edges are close enough to prevent leakage,
and the site is repeatedly sprayed with a solution of Heparin 500 units diluted in
100 cc of 0.9% normal saline to prevent drying and for intimal protection ([Video 1]).
Video 1Dr. Gajiwala's technique of arteriovenous fistula creation without using vascular
clamps through minimal access. Online content including video sequences viewable at:
https://www.thieme-connect. com/products/ejournals/html/10.1055/s-0041-1729503.
Fig. 1 Arteriovenous fistula platform.
Fig. 2 Forceps technique for arteriovenous fistula creation.
Fig. 3 Completed arteriovenous fistula.
After ensuring hemostasis, the proximal venous outflow is examined to release any
kink or compression or a band of tissue across. Aim is to see that proximal outflow
is larger and smoother than the distal one. Rarely, one may tie off the distal end
converting it into a side-to-end AVF.
The second method involved creating brachial artery–antebrachial vein/proximal radial or ulnar artery
and antebrachial or a perforating vein[6] AVF without using vascular clamps—a different challenge.
Here the surgery is performed under medial antebrachial cutaneous nerve block with
3 to 4 cm vertical incision parallel to the vessels between the artery and vein. After
isolating antebrachial vein, the biceps aponeurosis is divided lateral to medial just
sufficient enough to expose and isolate the brachial artery and its branches, radial
and ulnar, with gentle blunt dissection. A perforator vein connecting antebrachial
vein to deep vein is either ligated or used for AVF anastomosis and then disconnected
from deep vein to prevent diversion of AVF blood flow into a deep vein creating a
useless left to right shunt. The advantage of minimal access, creating optimal condition
for skin and soft tissue pressure that occludes arteriovenous segments, is missing
at elbow as the artery is deep and needs larger incision. Here the trick is to create
a smaller button hole in soft tissues below the arterial and venous segments that
would allow AVF platform or prongs of the forceps to pass though and stretch gently,
but the surrounding soft tissues will push the vessels downward creating an occlusion
of the lumen. However, before starting both brachial arteries and antebrachial vein
are secured with a double loop of a linen or a vascular loop ([Fig. 4]), which if needed can be tightened to prevent bleeding. Brachial artery (or proximal
radial or ulnar division)–antecubital vein (or deep perforator vein) is similarly
occluded with AVF platform or prongs of the forceps and 4 to 5 mm linear window is
created to do the anastomosis. A larger AVF may cause very large diversion of blood
flow into the vein leading to relative ischemia of the forearm and the hand or a huge
left to right shunt with high chances of cardiac failure.[7]
Fig. 4 Arteriovenous fistula being done at the elbow, over the forceps.
Results
In a functioning AVF dialysis, blood flow rate of 250 to 350 mL per minute was achieved
on an average and patients received dialysis for 3 to 4 hours per session on usually
twice- or thrice-a-week schedule. One of the first two cases done in the month of
August 2002 with 0.5 cm incision approach ([Figs. 5 ]) a very tiny window, is still functional after 18 years. This incision, half the
width of an adult finger nail, is quite challenging and took an average of 3 hours.
But for a larger incision of 0.8 to 1.5 cm, the time required was around 45 to 90
minutes. In general fistula first approach, before superficial veins were punctured,
had a better outcome. Also, it was found useful if patients, nurses, medical colleagues,
and anesthesiologists were educated regarding preserving cephalic vein, renaming it
as a “future kidney or a dialysis vein.” Early presurgery exercise of forearm muscles
developed better venous channels and ensured higher success rates.
Fig. 5 5-mm approach: 18 years of follow-up.
Discussion
Recent advances in surgeries have focused on MAS due to advantages of less pain, shorter
hospitalization, faster recovery, and smaller scars. A small incision is used as a
port of entry for an endoscope to view or to insert an instrument to manipulate, dissect,
coagulate, cut, and take a biopsy, requiring many ports to complete a surgery. Reduction
in pain seen in MAS leads to an idea of creating a successful functional AVF through
just 0.5 cm skin incision in 31 of 33 cases, with the use of a microscope. This opened
the possibility of creating successful AVF routinely through 1 to 1.5 cm skin incisions
mostly under ophthalmic loupe magnification, which was used later. This is not possible
with vascular clamps, which occupy a certain space. The idea presented here, to occlude
the lumen without using vascular clamps, is very simple indeed. The pressure to occlude
lumen comes from surrounding soft tissues, which is safer and least harmful to the
vessels, akin to soft tissue pressure-occlusion of different vessels when a tourniquet
is applied. Another advantage is that the technique brings a segment of artery and
vein in close proximity abutting each other, which makes anastomosis very easy and
gives an uncluttered, focused, bloodless surgical field where only a completely isolated
anastomotic site stabilized on a platform is seen. Further, the AVF platform or the
forceps separate the rest of the tissue away from the anastomotic field and avoid
soft tissue being caught up into the sutures while suturing the posterior wall. And
since the posterior cut edges are abutting each other, it makes it easier to suture
the posterior walls together without any struggle, pull, or much handling with the
forceps, and also avoids tension on the suture line and tears in the wall. With a
small incision, lesser number of cutaneous sensory nerve endings are cut and therefore
there is less pain. Painkillers are given only on patient demands, given to about
one out of three patients in this series, except for an AVF created at elbow. Bleeding
is less. And there has been no infection in this series. Wound gap is rare. Also,
there is less likelihood of creating a very high-flow fistula that can lead to cardiac
failures and steal phenomena.[7]
[8]
[9]
[10]
[11]
[12] The problem does, however, arise when one comes across a very thick atherosclerotic
blood vessel. Here a proper dissection and freeing of a longer segment of blood vessels
and gentle stretching is a key to prevent tears and disruptions in intima. At times
one finds that intima does crack and cholesterol plaques are jutting out of the edge
of an arteriotomy. Handling this vessel is fraught with danger of further damaging
the intima.[13] Intravenous heparin has very rarely been used in the postoperative period except
when there is severe atherosclerosis and is followed by low-molecular-weight heparin
and antiplatelet agents ([Table 1]). It is the high flow across the fistula that saves the day. Therefore, it is important
that patients do not become dehydrated. And with the help of a nephrologist adequate
fluid intake be calculated and instructions given to the patient. Most cases of early
thrombosis or failures have been due to atherosclerosis, small diameters of vein and
the artery, poor venous channels or veins with partial blockage due to intraluminal
thrombus due to previous intravenous infusions, dehydration that reduces blood flow,
compression of operative site, smoking, or some form of coagulopathy.[14]
[15]
[16]
[17]
[18] With small size of fistula, there are less chances of developing eddy currents and
thrombosis. On an average these fistulas develop between 400 and 800 mL of flow over
a period of time and are adequate for dialysis at the flow rate of 250 to 350 mL/minute.
But since all AVFs are a left-to-right shunt, this leads to an effective reduction
in ejection fraction. And many of these patients of end-stage renal disease along
with diabetes and hypertension also have associated cardiac problems like ischemic
heart disease, arrhythmias, and diabetes-related cardiac autonomic neuropathy and
poor cardiac function.[11]
[12] The small AVF rarely develops 1,500 to 2,000 mL/minute of flow rate, which is a
major cause of recurrent congestive heart failure in patients on maintenance hemodialysis.[12]
[19]
[20] There has been not a single case of steal syndrome. It may simply be that distal
venous outflow with arterialized blood provides alternate retrograde flow to the digits,
which is quite often seen in cases of venous hypertension. Another advantage of side-to-side
fistula is seen quite often, when due to repeated venipuncture a proximal venous outflow
shuts down, and the distal venous outflow creates another circuit through dorsal venous
arch. Or at times it provides two enlarged veins providing double access. There are
also disadvantages and difficulties, like the technique is time consuming specially
with 0.5 cm approach, which requires microscope, microsurgical skills, and patience.
Edema, obesity, scarring due to previous intravenous fluid extrusions, and patients
on blood thinners do pose a challenge in dissection through this small window and
a confined space. Also, one is unable to ligate number of venous tributaries to prevent
diversion, and relies on the principle that the venous flow will occur through the
path of least resistance. Also, there are higher chances of venous hypertension.[21]
[22] And one needs to at times ligate the distal venous outflow or its tributaries, to
redirect the flow. As with vascular clamp technique, in these series too there were
cases of either early thrombosis or failure of AVF to develop a good flow. Failure
to develop can best be explained in Dixon’s words, “maturation requires a compliant
and responsive vasculature capable of dilating in response to the increased velocity
of blood flowing into the newly created low-resistance circuit.”[23]
Table 1
Results: arteriovenous fistula (AVF) through minimal access
|
0.5 cm (33)
|
0.5–1.5 cm (503)
|
>1.5 cm (29)
|
At elbow (57)
|
Total (622)
|
|
Abbreviations: AVF, arteriovenous fistula; LMWH, low-molecular-weight heparin; VAES,
vascular access ecosystem.
Notes:
• VAES, enhanced by regular exercise, was used for two-needle hemodialysis after adequate
flow was established, mostly between 4 and 8 weeks. AVF was considered matured if
there were at least six consecutive successful dialysis.
• With ~90% having hypertension and 40% diabetes, 70% had some form of atherosclerosis.
Severe cases of atherosclerosis were given low-molecular-weight heparin postoperatively
at least for 5 days. All atherosclerotic patients were put on antiplatelet agents.
• Two cases of thrombosis that occurred within a day were explored and redo surgery
were done. Other thrombosis occurred much later.
• Bleeding occurred in four cases, following heparinized hemodialysis, which were
explored and controlled with protamine spray. No AVF leakage was seen.
• Mild wound gap of ~2 mm occurred in three patients near elbow, due to postoperative
edema that later healed spontaneously.
• An infected aneurysm occurred 2 years later, following infective endocarditis.
• Painkillers were given on demand in ~168 out of 565 cases of minimal access, except
in surgery at elbow.
Six out of 18 cases were of severe venous hypertension and 2 needed ligation of AVF.
Others needed ligation of distal venous outflow.
|
|
LMWH
|
2
|
49
|
4
|
6
|
61
|
|
Thrombosis
|
1
|
23
|
2
|
2
|
28
|
|
Failure to mature*
|
1
|
52
|
5
|
4
|
62
|
|
Bleeding
|
–
|
3**
|
1
|
–
|
4
|
|
Infection
|
–
|
–
|
–
|
–
|
–
|
|
Wound gap
|
–
|
–
|
–
|
3#
|
3
|
|
Hematoma
|
–
|
9
|
1
|
2
|
|
|
Pain killers needed
|
2*
|
154*
|
12
|
57
|
168/565
|
|
Venous hypertension
|
1
|
13
|
1
|
3
|
18
|
|
Vascular steal phenomenon
|
–
|
–
|
–
|
–
|
–
|
|
Aneurysm
|
–
|
1*
|
–
|
–
|
1
|
Conclusion
A new simple innovative concept is presented here to create an AVF through minimal
access without using vascular clamps that helps simplify surgery by bringing vessels
in juxtaposition thereby reducing tension at suture line, giving a clear unencumbered
field isolated from the surrounding tissues, with added benefit of less bleeding and
less postoperative pain.
