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390 A.N. Keeling
a
b
c
Fig. 39.1 A 71-year-old with painless obstructive jaundice secondary to a Klatskin tumor. Biliary
drainage was performed. Hemobilia from the biliary drain necessitated blood transfusion. A DSA
of the celiac artery demonstrated a large pseudoaneurysm arising from a right hepatic arterial
branch. As the vessel was in a non-critical vascular territory, it was elected to embolize both the
entry and exit arteries with coils, i.e., the sandwich technique, using a microcatheter. A repeat
DSA demonstrated no contrast filling of the feeder artery or the pseudoaneurysm (Keeling, A.N.,
McGrath, F.P., Lee, M.J., Interventional Radiology in the Diagnosis, Management, and Follow-Up
of Pseudoaneurysms, Cardiovascular and Interventional Radiology 2009; 32: 10)
39 Embolization of Visceral Arterial Aneurysms 391
Fig. 39.2a A 42-year-old alcoholic with acute pancreatitis became septic and thus had a contrast-
enhanced CT abdomen to identify any abscess formation. Of note there was a large abscess in the
left upper quadrant. This was drained at the time of the CT examination. However, there was also
a large splenic arterial pseudoaneurysm and an arterio-venous fistula between the splenic artery
and vein. (Keeling, A.N., McGrath, F.P., Lee, M.J., Interventional Radiology in the Diagnosis,
Management, and Follow-Up of Pseudoaneurysms, Cardiovascular and Interventional Radiology
2009; 32: 7)
Fig. 39.2b ADSAfollowing
coiling (coiling was
performed after treatment of
the local sepsis) of the
pseudoaneurysm
demonstrates no contrast
filling of the
pseudoaneurysm. Note also
the drainage catheter within
the large abscess cavity.
(Keeling, A.N., McGrath,
F.P., Lee, M.J., Interventional
Radiology in the Diagnosis,
Management, and Follow-Up
of Pseudoaneurysms,
Cardiovascular and
Interventional Radiology
2009; 32: 7)
392 A.N. Keeling
Fig. 39.2c A repeat contrast-enhanced CT abdomen 1 week later to check the abscess showed the
coils within the pseudoaneurysm sac. However, there is an enlargement of the sac with marked
contrast enhancement within it, indicating reperfusion (Keeling, A.N., McGrath, F.P., Lee, M.J.,
Interventional Radiology in the Diagnosis, Management, and Follow-Up of Pseudoaneurysms,
Cardiovascular and Interventional Radiology 2009; 32: 7)
Fig. 39.2d A repeat DSA
confirms t he CT findings and
demonstrates the sac filling
with contrast material.
(Keeling, A.N., McGrath,
F.P., Lee, M.J., Interventional
Radiology in the Diagnosis,
Management, and Follow-Up
of Pseudoaneurysms,
Cardiovascular and
Interventional Radiology
2009; 32: 7)
39 Embolization of Visceral Arterial Aneurysms 393
Fig. 39.2e The splenic artery proximal and distal to the neck of the psuedoaneurysm was coiled to
exclude the pseudoaneurysm. A repeat DSA confirms no filling of the sac with contrast. The pseudoaneurysm did not recur on follow-up CT. (Keeling, A.N., McGrath, F.P., Lee, M.J., Interventional
Radiology in the Diagnosis, Management, and Follow-Up of Pseudoaneurysms, Cardiovascular
and Interventional Radiology 2009; 32: 7)
Keypoints
• High mortality from visceral arterial aneurysm rupture.
• Embolization is a valuable life-saving procedure.
• Non-invasive imaging is useful for treatment planning.
• Treat ruptures, pseudoaneurysms, true aneurysms >2 cm, high-risk patients
– pregnancy, high flow states, transplants.
• Be aware of the different embolization techniques; consider combination
techniques.
• Stent-grafts are quick to deploy – consider if ruptured.
Suggested Reading
Tulsyan N, Kashyap VS, Greenbery RK, Sarac TP, Clair DG, Pierce G, Ouriel K. The endovascular
management of visceral artery aneurysms and pseudoaneurysms. J Vasc Surg 2007;45:276–283.
Sachdev U, Baril DT, Ellozy SH et al. Management of aneurysms involving branches of the celiac
and superior mesenteric arteries: a comparison of surgical and endovascular therapy. J Vasc Surg
2006;44:718–724.
Saltzberg SS, Maldonado TS, Lamparello PJ et al. Is endovascular therapy the preferred treatment
for all visceral artery aneurysms? Ann Vasc Surg 2005;19:507–515.
Carr SC, Pearce WH, Vogelzang RL, McCarthy WJ, Nemcek AA Jr, Yao JS. Current management
of visceral artery aneurysms. Surgery 1996;120:627–633.
Chapter 40
Renal Artery Aneurysms
M.J. Lee
Clinical Features
• Renal artery aneurysms (RAA) are rare, accounting for 0.1% of visceral
aneurysms.
• Sixty percent of patients are female, with the right kidney more often affected
than the left.
• Sixty percent of RAA occur at the division of the renal artery; only 10% are
intraparenchymal.
• 80% are saccular and 20% are fusiform.
• Causes include: fibro-muscular dysplasia, atherosclerosis, Ehler Danlos,
Marfans, trauma/iatrogenic.
• Other causes of smaller aneurysms include: polyarteritis nodosa and
amphetamine abuse.
• Aneurysms may also occur as part of angiomyolipoma.
• RAA is usually found incidentally and is often associated with hypertension.
• Rupture is the most feared complication. There is an increased risk of rupture
in pregnancy with a greater than 70% maternal mortality and almost 100% fetal
mortality.
Diagnostic Evaluation
Clinical
• Hypertension is commonly associated with RAA. Occasionally a bruit may be
auscultated over the kidney.
Laboratory
• Renal function should be measured.
Transcatheter Embolization and Therapy,
Techniques in Interventional Radiology, DOI 10.1007/978-1-84800-897-7_40,
C
Springer-Verlag London Limited 2010
395
396 M.J. Lee
Imaging
• Renal scintigraphy should be performed to document renal function as a base
line.
• CT angiography is the best test to elucidate the location of the aneurysm and
renal artery anatomy.
• If endovascular intervention is considered, angiography is useful to confirm CTA
findings and determine the best obliquity to display the aneurysm in profile.
Treatment Indications
• Size greater than 2 cm in males or post-menopausal women.
• Local complications, such as dissection, distal embolization or rupture.
• Urological symptoms such as hematuria or pain.
All women of childbearing age with RAA irrespective of size. Some investigators recommend treatment of RAA in this population only if the size is greater
than 1 cm
Contraindications
• These are relative as most RAA can be treated endovascularly, with novel embolic
techniques.
Equipment
• Equipment will vary depending on the method of treatment, but may include
some or all of the following:
• 5Fr cobra catheter or sidewinder
• 6Fr guiding catheter
• Microcatheters and microwires
• Detachable coils
• Amplatzer vascular plugs
• Detachable balloons
•Onyx
• Stents and stent grafts
Procedure
Access
• Access is usually through the groin, but occasionally may be from the arm.
40 Renal Artery Aneurysms 397
Angiography
• A flush aortogram is only needed if CT has not delineated the number and
location of the renal arteries.
• Selective angiography is then performed, with oblique or craniocaudad angula-
tion as required to fully display the aneurysm in profile. This is one circumstance
when rotational angiography can be helpful.
• Note: it is always worthwhile to perform angiography at a different session to
plan for treatment or to treat in a staged fashion for complex lesions.
Assessing Lesions
• The location of the aneurysm with regard to the main renal artery, branch vessels,
neck size (narrow or wide neck), and whether the lesion is intraparenchymal.
• For truly intraparenchymal lesions, it may be possible to sacrifice the portion of
the kidney supplied by the artery containing in the aneurysm. This, however, is a
rare occurrence.
Forming a Treatment Plan
• Numerous options are available depending on the location of the aneurysm,
and whether it has a narrow neck or wide neck. Not all RAAs are suitable for
endovascular treatment. If function is paramount and there are multiple branches
arising from the aneurysm, surgical alternatives such as bench dissection should
be considered.
Covered Stent
• Covered stents can be used if the RAA is arising from the main renal artery and
there is a proximal and distal landing zone.
• Remember most aneurysms are at the bifurcation of the main renal artery and
therefore use of a covered stent will involve sacrifice of renal tissue.
Balloon Remodeling
• This requires two vascular access points or use of a sheath/guide catheter able to
accommodate two separate catheter systems.
• Balloon remodeling can be used if the RAA has a wide neck, which increases the
risk of coil extrusion.
• A microcatheter is first placed into the RAA and a separate angioplasty balloon
inflated across the neck of the RAA.
398 M.J. Lee
• Using the balloon as a buttress the RAA can be coiled, preferable with detachable
coils until completely occluded. The balloon is then deflated and the balloon and
microcatheter removed.
• More than one modelling balloon may be necessary to protect the renal circula-
tion in complex aneurysms or when using polymers such as Onyx.
Bare Stent Assisted
• Stent-assisted coiling involves placement of a stent across an aneurysm neck, and
subsequent coil embolization through a microcatheter that is placed through the
interstices of the stent. The stent then keeps the coils from migrating back into
the feeding artery.
• Stent-assisted coiling can be used for bifurcation aneurysms, where there is a risk
of non-target embolization of adjacent branch arteries.
• Stents for neurointervention are preferred as they are quite flexible and have a
loosely woven mesh.
• Stents include the Neuroform stent (Boston Scientific), the Leo Stent (Pyramed),
the Enterprise Stent (Cordis), and the Solitaire Stent (EV3).
• Note: the Solitaire Stent is the only stent that is detachable, which means that
it can be either left permanently in situ or removed at the end of the coiling
procedure.
Primary Coiling
• Primary coiling is suitable for many RAA.
• Generally, if the neck of the aneurysm is less than 50% of the maximum diameter
of the aneurysm, primary coiling is often feasible.
• Detachable coils are preferred for control.
• A large framing coil is first inserted, with placement of additional coils until the
aneurysm is packed completely. The coil sizes can be reduced as the RAA fills
with coils.
• Consider using a hydrogel coil for the neck of the aneurysm (Hydrogel coils swell
to three to four times their normal size and are useful for occluding the neck of
the aneurysms.).
Performing the Embolization
• Remember that RAAs are often complex aneurysms, and decisions should be
made by a multidisciplinary team that includes experienced Transplant Urology,
Nephrology, and IR services.
40 Renal Artery Aneurysms 399
• Individual decisions are required for each patient because of the differing sizes
and locations of RAA.
• Once decided on a treatment plan, take your time and carry it out with care.
• Do not be afraid to call for help, if needed.
Embolization Endpoint
• The embolization procedure is complete when the entire aneurysm is excluded
including the neck. If the neck is not adequately embolized, there is a significant
risk of recanalization of the aneurysm.
Immediate Post-procedure Care
• Care is similar to all angioplasty procedures.
• Serum creatine is obtained after 24 h.
Long-Term Follow-Up
• Follow-up imaging can be difficult depending on the embolic agent used.
• If coils are used, they will often cause an acoustic shadow on ultrasound, making
it difficult to accurately visualize flow within the aneurysm.
• Similarly for MRA, coils can cause artifact making aneurysm assessment
difficult.
• Angiography is the most useful modality to exclude any reperfusion of the RAA.
Follow-up angiography is typically performed at 6-months. If the aneurysm
remains excluded on angiography at 6 months, follow-up with ultrasound, CTA,
or MRA can be performed at yearly intervals for up to 5 years.
Results
• Published results for endovascular aneurysm repair are limited as this is a rare
aneurysm.
• More and more small series using novel embolization techniques are appearing
in the literature.
Alternative Therapies
• Imaging follow-up is used for aneurysms that are under 2 cm in size in males or
post-menopausal women.
• A number of surgical options are available including the following.
400 M.J. Lee
In Vivo Aneurysmectomy
• This implies operating on the kidney in situ, with resection of the aneurysm and
either primary closure, patch angioplasty, or RAA resection with the placement
of a graft.
Ex Vivo Resection and Autotransplant
• Ex vivo resection implies removing the kidney and performing bench surgery to
remove the aneurysm and autotransplanting the kidney to the iliac artery.
Nephrectomy
• Either partial or total nephrectomies can be performed.
• The largest surgical series of 252 RAA in 168 patients had a total nephrectomy
rate of 28% (25 planned nephrectomies and 8 unplanned nephrectomies).
◦ During a mean follow-up over 91 months, there were two graft failures and a
60% significant decrease in blood pressure.
• Endovascular treatments are usually preferable where renal tissue can be
sacrificed.
Complications
• Complications mainly relate to non-target embolization.
• These can be avoided by meticulous attention to detail and careful treatment
planning.
• Considerable experience is necessary for treating complex RAA.
Keypoints
• The management plan should be made in consultation with the patient. All
relevant clinical staff should be involved in the decision-making process
(interventional radiologists, vascular surgeons, nephrologists, physicians,
and sometimes obstetricians) usually in the context of a multidisciplinary
team meeting.
• High-quality pre-procedural imaging is important for embolization planning.