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16 Systemic Arteriovenous Fistulae 163
Fig. 16.3 Unsubtracted
angiogram of a large AVF of
the extremity. Note how the
AVF is indistinguishable
angiographically from an
extensive AVM
◦ The catheter to be passed beyond the AVF.
◦ Injection into a collateral vessel that supplies the territory beyond the AVF.
◦ Use of a tourniquet or occlusion balloon to reduce venous outflow.
Clinical Scenarios
Etiology of Arteriovenous Fistulae
Congenital arteriovenous fistulae
• These are less common than true arteriovenous malformations, which tend to
have more complex anatomic patterns.
• Examples of true congenital fistulae include those occurring in the central
nervous system (dural, carotid-cavernous), pulmonary AVMs (which typically
resemble fistulas more than true malformations), coronary artery fistulae, and
those in the kidney.
164 R. Rosen
Traumatic arteriovenous fistulae can occur anywhere in the body after a pene-
trating injury, and they were historically the first type of AVF described.
• These lesions are often not apparent until some time after the acute event,
when secondary changes such as abnormal pulsation, a palpable thrill, swelling,
enlarged regional arteries and veins, and distal ischemia may be noted.
• When the lesion is deep seated, the first sign may be that of a high-output
cardiac state.
Iatrogenic arteriovenous fistulae are occurring more frequently with the increasing use of minimally invasive techniques, where a vascular injury may not be
immediately apparent.
AVF in Specific Locations
Renal AVF
• Manifest clinically with renal impairment, hypertension, hematuria, flank pain,
or asymptomatic bruit.
• Acquired fistulae may result from penetrating trauma or iatrogenic injuries such
as renal biopsy, nephrostomy, or percutaneous stone removal.
Small Post-biopsy Renal AVF
• Often resolve without specific treatment; larger fistulae often show progressive
enlargement, related to the high flow rate in the renal circulation.
• Require treatment if symptomatic, especially if associated with reduction in renal
function in a renal transplant.
• Embolization is usually straightforward and should be as selective as possible to
minimize renal parenchymal loss.
Congenital and Large Renal Arteriovenous Fistulae
• These lesions are generally supplied by a single very dilated renal artery branch
with a massive draining vein.
• The flow through these lesions is so high that there is often dilation of the inferior
vena cava, and there may be associated high-output heart failure.
• Massive renal AVF can be problematic to treat due to the size of the AV communi-
cation and the torrential flow.
• There is a significant risk of loss of the embolic device through the fistula and
into the pulmonary circulation.
• A combination of inflow and outflow occlusion balloon flow control, oversized
coils, vascular plugs, and in some cases liquid agents (nBCA, Onyx) may be
necessary to completely close these lesions.
16 Systemic Arteriovenous Fistulae 165
Arterioportal Fistuale
• Generally present with gastrointestinal bleeding due to arterialization of portal
flow (Fig. 16.4).
Fig. 16.4 Digital subtraction angiogram of the common hepatic artery (arrowhead) demonstrating
early filling of the portal vein (arrows) as a result of an arterioportal fistula
• This type of arterialization is also sometimes encountered in aggressive hepato-
cellular carcinoma with rapid arteriovenous shunting through the tumor.
• Care must be taken to avoid loss of embolic materials or devices through the
fistula and into the portal vein.
• An additional risk is acute thrombosis of the portal system shortly after closing
the fistula, presumably due to the acute decrease in pressure in the portal system.
Aortocaval Fistulae
• Uncommon, usually related to erosion of an aortic aneurysm through the caval
wall, penetrating trauma, or iatrogenic injury (particularly during lumbar disc
surgery).
• Clinically these patients present with abdominal bruit, pulsatile abdominal mass,
widened pulse pressure, and in some cases, renal failure.
• Flow through this type of fistula is extremely high and often results in high-output
cardiac failure.
• In the vast majority of these cases, the fistula is side-to-side, and embolization
plays little role.
• Endoluminal aortic stent grafts have recently been used to successfully man-
age this problem while avoiding the risk of free hemorrhage during open repair
(Fig. 16.5).
166 R. Rosen
(a) (b)
Fig. 16.5 a) Digital subtraction aortic angiogram demonstrating an early draining IVC (arrow),
due to fistula formation between an aortic aneurysm (arrowhead)andtheIVC.b) Angiogram
following stent-graft placement, demonstrating complete resolution of the fistula
Treatment Plan and Technique
• The key to successful treatment of an arteriovenous fistula is finding and closing
the point of communication between the artery and the vein.
• Choose the correct embolic agent before starting the embolization.
Coil embolization is suitable if the afferent artery can be safely sacrificed and the
size and flow rate of the fistula permit them to be securely deployed without risk of
migration.
• The initial coils should generally be oversized to create a baffle or nest that will
allow the subsequent coils to be safely packed to achieve complete occlusion.
• In larger or higher flow fistulae, the use of detachable coils allows for trial sizing
and coil placement prior to release in order to avoid escape of the device through
the draining vein.
• An “anchor” approach has been described by White et al., consisting of placing
the end of the coil in a more proximal branch to anchor it in place and prevent
migration.
• While coil retrieval is an interesting and challenging procedure, it is better
avoided by careful planning!
16 Systemic Arteriovenous Fistulae 167
Other occlusion devices
• Detachable plugs such as the Amplatzer device offer many of the same advan-
tages as coils and are simple to use (Fig. 16.6).
• In very large side-to-side fistulae, occluding devices primarily designed for
cardiac use (ASD and VSD closure) have also been used successfully.
• Detachable occlusion balloons were used extensively in the past, but are currently
not commercially available in the United States.
Liquid agents: adhesives (n-butyl cyanoacrylate) and polymers (Onyx) may be
useful in certain types of fistulae where achieving a complete seal is difficult.
a
b
c
Fig. 16.6 a) Unsubtracted angiogram demonstrating a pulmonary AVM (AVF) with a single feed-
ing artery and a single draining vein. b) Unsubtracted image demonstrating a single Amplatzer
device in the feeding artery. c) Unsubtracted image from the post-embolization angiogram
demonstrating complete resolution of the AVM
168 R. Rosen
• Even though the acrylic adhesives can be prepared to form an almost instanta-
neous cast, they are best used after flow has been diminished somewhat by the
initial placement of coils or other devices, or alternatively by using a proximal
balloon to control inflow during the embolization process.
Covered stents: if the fistula is side-to-side or if flow through the involved artery
and vein must be preserved, the use of covered stents or stent-grafts may be an
effective solution (Fig. 16.7).
• As in surgical ligation, they should only be used when there are no branches that
could recanalize the fistula over time.
• The long-term patency of a covered stent must also be taken into consideration,
particularly in younger patients.
a
Fig. 16.7 a) Unsubtracted pelvic angiogram demonstrating an early draining iliac vein (arrow)
during a common iliac artery injection. b) Angiogram following deployment of a stent-graft
demonstrates complete resolution of the AVF
b
Approach
Artery
• Most AVF will be approached from the arterial end; this also allows access into
the draining vein (through the fistula) if necessary.
16 Systemic Arteriovenous Fistulae 169
Ve in
• The venous approach has been described in
◦ Carotid-cavernous fistulae
◦ Vein of Galen “aneurysms”
◦ Certain peripheral arteriovenous fistulae and fistula-like malformations
• If the draining vein can be completely occluded, the arterial feeders will have no
low-pressure sump to empty into, resulting in immediate cessation of flow.
• This approach can be performed via transvenous catheterization or by direct
puncture of the draining vein if it is accessible, and usually involves completely
packing the venous structure with coils and/or liquid agents.
Both
• In high-flow AVF where the risk of systemic embolization is high, consider using
balloons to occlude the inflow and/or outflow vessels.
Technical Points
• The first treatment should be carefully planned and executed, as it represents the
best chance for a permanent cure.
• Simply occluding the feeding artery proximal to the fistula will generally result
in long-term failure due to recruitment and enlargement of collateral branches
closer to the point of arteriovenous communication. Thus, there is not only recurrence of the fistula, but it is now supplied by multiple smaller branches, making
subsequent treatment much more difficult.
• A distinct advantage of endovascular therapy is the ability to obtain detailed,
dynamic images of the point of communication.
• In classic “H”-type AVF, four vessels must be considered: the inflow artery, the
outflow artery, and the outflow veins upstream and downstream of the AVF. Each
of these segments will undergo significant morphologic change.
• The tendency of fistulae to persist or recur suggests that the procedure
should not be considered finished until flow has been completely arrested
angiographically.
• Although the goal should always be occlusion of the actual fistula site, t his may
prove impossible in some situations, and reducing flow through collateral feeders
may be the only therapeutic option, knowing that further collateral recruitment is
inevitable over time.
Aftercare
• In the setting of embolization of a very large AVF, immediate changes in the
patients hemodynamic status can occur.
170 R. Rosen
• This is particularly true of patients who present with high-output cardiac failure.
Close evaluation of such patients in the immediate post-embolization period is
vital!
• Consideration should be given for ICU admissions with close hemodynamic
monitoring.
Arterial Puncture Site
• Normal post-angiography care.
Post-embolization
• Post-procedure pain medications and anti-inflammatory medications, as outlined
above, should be considered.
Follow-Up
• Routine clinical follow-up within a week is recommended.
• Imaging follow-up with cross-sectional imaging within several weeks is recom-
mended to evaluate for incomplete embolization or recurrence of the AVF.
• Non-invasive imaging is generally adequate; the imaging modality used prior
to embolization would allow direct comparison of pre- and post-intervention
studies.
Keypoints
• Arteriovenous fistulae are, by definition, direct anatomic connections
between artery and vein that should be completely curable, unlike some
more complex malformations.
• Endovascular techniques are particularly well suited for managing this
type of clinical problem, whether by embolization or by stent grafting.
• The best opportunity for complete cure is the initial procedure.
• Careful delineation of the pathologic anatomy and the correct choice of
endovascular device are essential.
• Failure to occlude the actual site of connection between artery and vein
is likely to lead to rapid recurrence with a much more complex pattern of
collateral supply, at which point cure becomes difficult or impossible to
achieve.
16 Systemic Arteriovenous Fistulae 171
Safety
• Correct sizing of embolic materials such as coils is vital to decrease the
likelihood of migration of embolic agent.
• Rapid changes in hemodynamic status can occur following complete
occlusion of high-flow arteriovenous fistulae.
Suggested Readings
Holman, E., Arteriovenous aneurism: clinical evidence correlating size of fistula with changes in
the heart and proximal vessels. Ann Surg, 1924. 80(6): 801–16.
Early, S.A., et al., Coronary artery fistula; coronary computed topography—the diagnostic
modality of choice. J Cardiothorac Surg, 2008. 3: 41.
Burchell, H.B., Observations on bradycardia produced by occlusion of an artery proximal to an
arteriovenous fistula (Nicoladoni-Branham sign). Med Clin North Am, 1958. 42(4): 1029–35.
Iloreta, A.T. and M.D. Blaufox, Natural history of post-biopsy renal arteriovenous fistula: a 10-
year follow-up. Nephron, 1979. 24(5): 250–3.
Criado, E., et al., Endovascular repair of peripheral aneurysms, pseudoaneurysms, and arteriove-
nous fistulas. Ann Vasc Surg, 1997. 11(3): 256–63.
Halabi, A.R. and D.E. Kandzari, The thrill is gone: catheter-based exclusion of a posttraumatic
arteriovenous fistula with a covered stent graft. Catheter Cardiovasc Interv, 2005. 66(1): 27–33.
Hart, J.P., et al., Endovascular exclusion of iliac artery to iliac vein fistula after lumbar disk surgery.
J Vasc Surg, 2003. 37(5): 1091–3.
Donmez, H., et al., Use of a balloon and N-butyl-2-cyanoacrylate for treatment of arteriovenous
fistula. Cardiovasc Intervent Radiol, 2008. 31(Suppl 2): S111–4.
Peynircioglu, B., et al., Transvenous embolization of a spontaneous femoral AVF 5 years after
an incomplete treatment with arterial stent-grafts. Cardiovasc Intervent Radiol, 2008. 31(2):
407–10.
Casasco, A., et al., Percutaneous transvenous catheterization and embolization of vein of galen
aneurysms. Neurosurgery, 1991. 28(2): 260–6.
White, R.I., Jr., Pulmonary arteriovenous malformations: how do I embolize? Tech Vasc Interv
Radiol, 2007. 10(4): 283–90.
Chivate, J.G. and R.W. Blewitt, Congenital renal arteriovenous fistula. Br J Urol, 1993. 71(3):
358–9.
Guzman, E.A., McCahill, L.E., and F.B. Rogers, Arterioportal fistulas: introduction of a novel
classification with therapeutic implications. J Gastrointest Surg, 2006. 10(4): 543–50.
Kashyap V.S. et al., Aortocaval fistula. J Am Coll Surg, 2006. 203(5): 780–86.
Mitchell, M.E., McDaniel, H.B., and F.W. Rushton, Endovascular repair of a chronic aortocaval
fistula using a thoracic aortic endoprosthesis. Ann Vasc Surg 2008. 22: 742–9.
Barley, F., Kessel. DO., Nicholson, AA and I. Robertson Technical report: balloon occlusion to
reduce flow during selective embolization of large symptomatic iatrogenic renal transplant
arteriovenous fistula. Cardiovasc Intervent Radiol. 2006;29: 1084–7.
Chapter 17
Klippel-Trenaunay Syndrome
Peter Gaines
Klippel-Trenaunay syndrome has been included in this book since those involved
with treating vascular malformations are likely to encounter such cases. The importance is in recognizing the condition and avoiding the temptation to embark on
embolization therapy unless focal symptoms demand.
Diagnosis
• Klippel-Trenaunay syndrome is a clinical diagnosis.
• Only very rarely is the syndrome inherited.
• Two of the following three features are required for diagnosis of the syndrome.
1. Capillary malformation of the skin (98% of cases) (Fig. 17.1).
2. Venous malformation (72% of cases) (Fig. 17.2).
3. Hypertrophy of bone and soft tissues (67% of cases) (Fig. 17.1).
Clinical Features
The syndrome principally affects a single limb, most commonly the legs (90%), but
it may affect the arms (10%) or be bilateral.
Capillary Malformation (Fig. 17.1)
• Typically referred to as a “port wine stain.”
• Most commonly affects the limb affected by the other features.
• When it extends to the trunk it extends to, or just over, the midline.
• Only rarely complicated by bleeding, infection, or ulceration.
Transcatheter Embolization and Therapy,
Techniques in Interventional Radiology, DOI 10.1007/978-1-84800-897-7_17,
C
Springer-Verlag London Limited 2010
173