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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3955_Библиотеки_им_академика_М_И_Перельмана.pdf
Endovascular Management of Ruptured Abdominal Aortic Aneurysm 243
• A 12F ≥45 cm sheath to support an occlusion balloon inserted from a brachial
access
• A molding balloon (can be used for aortic occlusion)
• A range of angioplasty balloons and stents to deal with access vessel stenoses
• A giant balloon expandable stent for proximal aneurysm neck, e.g., Palmaz stent
(Johnson & Johnson)
• 25 and 30-mm diameter balloon for insertion of the giant balloon-expandable
stent into the proximal aneurysm neck
Guidewires
• Standard guidewires for access
• Stiff guidewires – e.g., Lunderquist 260 cm or Back up Meier guidewire 260 cm
• Hydrophilic/selective wires for cannulation of the contralateral limb opening and
for negotiating tortuous iliac arteries
Procedure
Resuscitation/Anesthesia
• Hypotensive resuscitation: Fluid administration should be kept to the minimum
required to maintain cerebral perfusion as indicated by the level of consciousness
and systolic BP ≥60 mmHg.
• Only once the aneurysm is excluded, should volume replacement begin.
• An early request for fresh frozen plasma or other coagulation factor replacement
should be considered.
• The procedure should preferably be started under local anesthesia; some sedation
may be required. The entire procedure can frequently be performed under local
anesthesia, including femorofemoral cross-over grafting.
• General anesthesia should be avoided until the aneurysm is excluded to prevent
precipitous hemodynamic decompensation during muscle relaxation.
• It should be emphasized that the volume of concealed blood in the retroperi-
toneum or peritoneal cavity, which cannot be seen, must still be replaced.
Access
• Percutaneous access is attractive for bifurcated systems, and in less stable
patients.
• Surgical exposure of the femoral arteries can assist delivery system insertion in
diseased access vessels, and will be required for AUI systems, as a fem–fem
cross-over graft.
244 W.C. Loan and C.V. Soong
• In a grossly unstable patient an occlusion balloon can be inserted percutaneously
from femoral access. Inflating the balloon at the top of a 16F sheath, and
using a stiff/super stiff guidewire will allow balloon position to be maintained.
(Fig. 2a, b) An assistant should be tasked with maintaining balloon position,
which must be checked frequently.
• It is possible for operators to gain access simultaneously on both sides, requiring
two sets of puncture needles/wires to be available on the trolley.
a
b
Fig. 2 (a) A molding balloon supported by a sheath to improve stability of balloon during occlu-
sion. (b) Balloon system as seen in (a), balloon inflated in the sac and advanced into the aneurysm
neck, allowing aortic occlusion without causing mesenteric and renal ischemia. Note the conical
upper surface of the balloon as it is held against the aneurysm neck from below. The calibrated
catheter alongside the balloon allows imaging and measurement during balloon occlusion
Initial Angiography
Following Pre-operative CT
• There should be no need for angiography prior to insertion of the stent-graft
delivery system.
• The first digital subtraction run can be delayed until the system is placed at the
approximate level of the renal arteries.
• High-quality imaging is critical to enable rapid, accurate deployment of devices
in emergency cases.
• A significant proportion of patients with ruptured AAA are obese. This may limit
image quality and increase radiation exposure to the patient and staff.
Primary Imaging with Angiography
• Calibrated angiography allows sufficiently accurate evaluation of the anatomy
and measurement.
Endovascular Management of Ruptured Abdominal Aortic Aneurysm 245
• Should the patient deteriorate, the aorta can be occluded, and both angiography
and graft insertion can be carried out with an occlusion balloon in place.
Clinical Scenarios
The specific procedure plan is dependent upon the clinical setting.
A “Stable” Patient
• Avoid aortic occlusion.
• The endograft insertion procedure similar to elective cases.
• Avoid general anesthesia.
• Regional anesthesia can be time consuming; local anesthesia is sufficient at least
until the aneurysm is excluded.
Continuing stability cannot be assumed, decompensation can be extremely rapid.
An Unstable Patient
• Rapid exclusion of the aneurysm is the priority.
• Aortouniiliac devices allow more reliable, rapid aneurysm exclusion.
• Balloon occlusion can be maintained in an infra-renal position, with rapid move-
ment to a supra-celiac position and reinflation possible if required. The stent-graft
can be deployed alongside the sheath supporting the balloon. The balloon can
then be removed through the sheath, which will slide out alongside the graft.
• The duration of balloon occlusion, particularly in the supra-renal position should
be kept to a minimum.
Management of Iliac Aneurysms
• Rupture of isolated iliac aneurysms is rare.
• Aortoiliac aneurysms are relatively common, requiring graft extension into the
external iliac artery, with embolization of the internal iliac artery.
• Internal iliac embolization can be time consuming. A vascular occlusion plug
(Amplatzer) can reduce the time to aneurysm exclusion.
• Avoid excessive over-sizing of the graft to be implanted into the external iliac
artery.Plan to leave the distal end of the device in as straight a segment of external
iliac artery as possible.
• Completion angiography must be carried out after stiff wires have been removed,
to visualized any kinking, particularly of the external iliac arteries.
• Insertion of uncovered stents may be necessary to overcome kinking at distal
landing zones.
246 W.C. Loan and C.V. Soong
Detection of Procedural Endoleaks
Patient Stable
• Perform careful angiography of the proximal anastomosis first.
b
Use a high rate of injection.
b
Use a fast frame rate acquisition.
b
Image in two planes.
• Pull down the catheter into the body of the graft. Perform angiography with a
reduced injection rate of approximately 7 mL/s to ensure contrast does not reflux
above the top of graft.
b
If the leak is still present, it is not a proximal type 1 endoleak.
• Repeat angiography with balloons inflated in both iliac arteries to occlude flow.
b
Inject contrast from below via the balloon catheters.
b
Use a rapid frame rate.
b
Contrast will “spill” out of the leak when it reaches the level of the leak.
• Minor leaks (type 4 or 2) can be left, if hemodynamic stability is maintained.
Patient Unstable: Requiring Significant Fluid Volumes to Maintain
Consciousness and Systolic ≥ 60 mmHg
• The occlusion balloon can be inflated initially in the supra-renal position and
angiography performed beneath the balloon.
• Should the proximal seal appear intact, the balloon can be repositioned in the
juxta- or infrarenal position. The balloon must be supported with a large sheath
to prevent the water hammer effect dislodging the balloon and possibly also the
graft.
Management of Procedural Endoleaks
• Type 1 leaks: Proximal or distal. If there is room, extend the endograft coverage
with a cuff for a proximal leak, a limb extension for a distal leak, or a Palmaz
stent to increase radial force.
• Type 2 leaks: These can generally be left as long as the patient is maintaining
hemodynamic stability.
• Type 3 leak: Repeat balloon dilation of the junctions between device components;
if this fails bridge the junction with a further stent-graft.
• Type 4 leaks: These do not appear to cause significant problems, at least in the
short or medium term.
Endovascular Management of Ruptured Abdominal Aortic Aneurysm 247
Aftercare
• Immediate post-operative imaging is generally not necessary unless there is
evidence of continued or recurrent bleeding.
• Adequate blood transfusion and fluid replacement is difficult to gauge, as visible
and recordable intra-operative blood loss will not reflect the true loss of blood
volume.
• Intensive care is frequently, but not universally necessary. The average ICU stay
post-operatively is on average, around 1 day.
• High ventilation pressures and abdominal distension with poor urine output
suggest abdominal compartment syndrome. Intra-abdominal pressure can be
monitored via the urinary catheter. Early decompression may be necessary.
• Prolonged restriction of oral intake may be necessary. This may be related to
delayed gastric emptying, perhaps due to retroperitoneal hematoma impinging
upon the duodenum.
Follow-Up
• These patients have worse anatomy and often more advanced disease than elec-
tive patients. The follow-up therefore needs to be at least as intensive as for
elective patients.
• CT is the mainstay of follow-up imaging. However, contrast-enhanced ultrasound
and MRI can aid endoleak detection and characterization.
• Plain X-rays of abdomen should be performed to identify wire fracture and
impending or established separation of components.
Results
• The published data are limited.
• The mortality of open repair for ruptured aneurysms is around 41%, despite
improvements in surgical techniques, anesthesia and intensive care support.
• The outcomes of eEVAR vary greatly from center to center and reflect reporting
bias and differences in patient selection.
• A recent metaanalysis of the worldwide experience from 48 centers involving
442 patients demonstrated an average mortality of 18%.
• A randomized trial comparing eEVAR with open repair, failed to demonstrate any
difference between the two groups, although the findings have been the subject
of great controversy.
• There is as yet no strong evidence that eEVAR is better than surgery, especially
in unstable patients.
248 W.C. Loan and C.V. Soong
Alternative Therapies
• Open surgical repair
• Palliative care
Complications
Early
• Thrombosis/Coagulopathy
b
These patients are not routinely heparinized and thrombosis of the graft is not
uncommon. With the common femoral arteries exposed, balloon thrombec-
tomy is usually straightforward. Beware not to dislodge the proximal end of
the graft.
b
Thromboembolic events in the legs are common. These should be treated by
balloon thromboembolectomy.
b
Despite the lack of visible blood loss, clotting factors are diminished and
coagulopathy should be suspected if hemodynamic control proves difficult to
achieve. Early replacement of lost factors should be considered.
• Failure to seal with continued hemorrhage.
• Injury to access vessels: dissection/perforation/avulsion of iliac arteries.
• Impairment of the various organs: renal failure, respiratory failure, cardiac
failure, and intestinal ileus.
• Intestinal ischemia.
• Abdominal compartment syndrome.
• Gastric outlet obstruction by hematoma.
• Deep vein thrombosis.
Late
• Late complications of eEVAR are similar to those of elective EVAR. However,
probably due to less favorable anatomy, or more advanced aneurysmal disease,
they seem to be more common.
• The presence of uncovered stents at the proximal neck of the graft can complicate
the management of migration and proximal endoleaks (Fig. 3).
• Graft infection is probably more common than in elective series.
• Conversion to open repair as an elective procedure to manage late complications
may be necessary. However endovascular management of most complications is
possible, and in general, is associated with a low morbidity.
Endovascular Management of Ruptured Abdominal Aortic Aneurysm 249
Fig. 3 Follow-up CT of an
AUI graft inserted for rupture
showing kinking of the graft
body and distal migration.
This occurred despite a large
self-expanding stent which
was inserted for a type 1
endoleak intra-operatively,
and has been left behind by
migration of the stent-graft.
Treatment by a proximal
extension is made more
difficult by the presence of
the balloon-expandable stent
Key Points
• Agree a management protocol with a multidisciplinary team in advance.
• Assessment of CT/Angiogram for suitability must be carried out by
specialists with extensive experience in planning elective cases.
• Not every case is suitable. Each must be assessed realistically.
• It is impossible to predict future stability of a patient with a ruptured
aneurysm.
• Do not waste time and have a plan for managing the unstable patient.
Suggested Reading
1. Badger SA, O’donnell ME, Makar RR, Loan W, Lee B, Soong CV. Aortic necks of ruptured
abdominal aneurysms dilate more than asymptomatic aneurysms after endovascular repair.
J Vasc Surg 2006 Aug; 44(2):244–9.
250 W.C. Loan and C.V. Soong
2. Frank J. Veith, Takao Ohki, Evan C. Lipsitz, William D. Suggs, Jacob Cynamon Treatment
of ruptured abdominal aneurysms with stent grafts: a new gold standard? Seminars Vasc Surg
2003 June; 16(2):171–5.
3. Malina M, Veith F, Ivancev K, Sonesson B. Balloon occlusion of the aorta during endovascular
repair of ruptured abdominal aortic aneurysm. J Endovasc Ther 2005 Oct; 12(5):556–9.
4. Matsuda H, Tanaka Y, Hino Y, Matsukawa R, Ozaki N, Okada K, Tsukube T, Tsuji Y, Okita
Y. Transbrachial arterial insertion of aortic occlusion balloon catheter in patients with shock
from ruptured abdominal aortic aneurysm. J Vasc Surg 2003 Dec; 38(6):1293–6.
5. Rose DF, Davidson IR, Hinchliffe RJ, Whitaker SC, Gregson RH, MacSweeney ST, Hopkinson
BR. Anatomical suitability of ruptured abdominal aortic aneurysms for endovascular repair.
J Endovasc Ther 2003 Jun; 10(3):453–7.
Angioplasty/Stenting/Lysis/Thrombectomy
of Hemodialysis Access
Himanshu Shah and Gordon McLennan
Clinical Features
• Chronic kidney disease (CKD) affects approximately one in nine people in the
United States with over 300,000 patients on hemodialysis.
• Hemodialysis access failure is a major cause of morbidity, cost, and hospitaliza-
tion for patients with end-stage renal disease.
• Access stenosis is a major cause of dialysis access (graft, fistula) failure.
• Screening combined with prophylactic angioplasty lowers the rate of dialysis
access thrombosis.
• The National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative
(K/DOQI) provides evidence-based clinical practice guidelines for the placement
and management of hemodialysis access.
Diagnostic Evaluation
Clinical
• Access dysfunction is screened at the dialysis center and patients are referred for
intervention when an abnormal screening parameter is identified.
• K/DOQI guidelines recommend at least monthly screening with physical exam
as well as surveillance by measuring access flow (e.g., Transonic device), venous
pressures, recirculation, or by duplex ultrasound.
• Patients with an abnormal screening parameter are sent for a fistulogram and
intervention.
• Access stenosis is the most common cause of dialysis graft failure. It results in
an increase in intra-access pressure, decrease in flow rate, and ultimately leads to
thrombosis.
Imaging
• Neointimal hyperplasia is the most common cause of access stenosis in the
outflow veins. A less common cause is valve hypertrophy (Fig. 1).
251
R.A. Morgan, E. Walser (eds.), Handbook of Angioplasty and Stenting Procedures,
Techniques in Interventional Radiology, DOI 10.1007/978-1-84800-399-6_20,
C
Springer-Verlag London Limited 2010
252 H. Shah and G. McLennan
Fig. 1 (a) Dialysis
fistulogram shows a
hypertrophied valve in the
outflow forearm cephalic vein
resulting in significant
stenosis as evidenced by
jetting of contrast. (b)
Significant stenosis is also
evident by the “waist” on the
angioplasty balloon during
balloon inflation
• Concentrated needle sticks can result in stenosis or dilatation/aneurysm formation
(Fig. 2).
• Central venous stenosis and occlusion is often secondary to prior central venous
catheters (especially subclavian vein catheters) but may also be secondary to prior
trauma, surgery, or pacemakers (Fig. 3).
• The classic location of stenoses in native dialysis fistulae is in the juxta-
anastomotic outflow vein. In dialysis grafts the classic location is at the venous
anastomosis (Fig. 4).
• Stenosis can occur anywhere along the dialysis access circuit including the
inflow artery, intragraft, at the arteriovenous anastomosis, at the arterial or venous
anastomoses, in the outflow vein, or in the central veins.
Fig. 2 Forearm dialysis graft
with large arterial limb and
venous limb
pseudoaneurysms