Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3869_Библиотеки_им_академика_М_И_Перельмана.pdf
30 Embolization in Post-operative Hemorrhage 295
◦ In the presence of sepsis, embolization should be regarded as a temporizing
measure
• Embolization is often used in certain post-radiation or post-surgical settings, due
to the surgical challenges in such populations.
• The clinical scenario (e.g., hemodynamic stability) largely determines the
urgency of the embolization.
Alternative Therapies
Surgical Repair
• Surgery typically is reserved for patients in whom embolization fails or where
surgical treatment is less risky than transcatheter therapy (e.g., brachial artery
injuries). Remember that repeat surgery can be very difficult in the presence of
adhesions and inflammation.
• Emergency surgery may be necessary if there is any delay obtaining angiographic
intervention.
• It will also be required if, in addition to bleeding, there are other problems such
as sepsis, tissue infarction or anastomotic breakdown.
Alternative Interventional Techniques
• Stents, stent grafts
• Direct puncture with thrombin injection, e.g., common femoral artery pseudoa-
neurysm
Contraindications
• All contraindications are relative in the context of life-threatening bleeding.
• Incorrectable coagulopathy: it is usually better to have a live patient with an
arterial sheath in situ; it can always be removed later when the patient has
stabilized.
• Bleeding foci that are too dangerous to embolize due to inability to sacrifice
downstream organ, e.g., the brain. In the presence of life-threatening hemorrhage,
normal rules do not apply. If there is no surgical alternative, then it is even acceptable to sacrifice a transplant hepatic artery end, though repeat transplant might
subsequently be required.
• In some cases, preservation of flow may be possible in which case stent-graft
placement may be more appropriate, e.g., brachiocephalic artery injury during
attempted central line placement.
296 K. Wright and B. English
Specific Complications
• Embolization following a recent operation might be disadvantageous, due to
the decreased likelihood of adequate healing in the setting of post-embolization
ischemia, e.g., anastomotic breakdown.
• Risk of contrast nephropathy, which may be higher in hemodynamically compromised patients.
• Access-related hemorrhagic complications including pseudoaneurym are more
common if there is coagulopathy.
• “Post-embolization syndrome” following ischemia or infarction of an embolized
organ, with symptoms including pain, fever, nausea, vomiting, and leukocytosis.
Anatomic Considerations
• Specific challenges in the post-operative patient are as follows:
◦ Normal vascular anatomy may have been affected by the surgery. Vessels
may have been ligated or there may be extra anatomic conduits especially in
transplants.
◦ Embolization might be difficult if the normal vasculature was sacrificed during
the operation. Collaterals may have to be s elected, and may prove to be much
more difficult to embolize.
• The ability to embolize depends on the presence of collateral vessels and/or the
ability to sacrifice downstream supply.
◦ Example: embolization within the pelvis is generally possible, due to adequate
collateral vasculature. However, embolization of the main renal artery may
result in renal infarction due to its end-arterial supply. Do not forget better
alive on dialysis than dead.
• Must assess the collateral vasculature prior to embolization. This is generally
accomplished by performing a more central angiogram.
Equipment
• Catheter selection depends on the target vessel size and specific embolic agent to
be employed (Section 1).
• Microcatheters allow for more distal placement and superselection of the targeted
vessel, resulting in more selective embolization. This preserves adjacent tissue
and collateral vessels.
• Sheaths appropriately sized.
30 Embolization in Post-operative Hemorrhage 297
Embolic Agents
This will depend on the exact circumstances and vessels to be occluded; the most
common embolic agents are as follows:
• Coils and microcoils.
• Amplatzer device.
• Gelfoam.
• Polyvinyl alcohol particles.
• Glue.
• Stent grafts are used in large-vessel endovascular repair, such as rupture, false
aneurysm, and AVFs, where preservation of distal flow is desirable.
• An occlusion balloon can be used to transiently occlude an artery and control
bleeding until surgical control is achieved.
Medication
Systemic
• Supportive therapy: blood products, IV fluids, vasopressor support, sedation, and
analgesia.
• Hyoscine to stop peristalsis: remember to let the aneshetist know why the patient
is getting a tachycardia!
• In rare select cases, paralytic agents (succinlycholine, vecuronium) may be
required in order to eliminate motion to facilitate superselective catheterization.
Transcatheter
◦ Adjunctive therapy may include vasoconstrictive agents, notably when temporary
control is needed in an arterial bed only (e.g., temporizing method before the
patient can return to the operating room).
◦ Primarily vasopressin is utilized, causing smooth muscle contraction.
Procedure
• Access
◦ Preferred access is via femoral artery for simple/quick access.
◦ Consider brachial or axillary approach if lower extremity access is not
available.
298 K. Wright and B. English
Angiography and Embolization
• Required to assess vascular injury, the presence of collateral vasculature, and
evaluate for variant anatomy.
• “High, hot, and a helluva lot.” Bleeding vessels should be assessed by more proximal injections (high), high-injection rates (hot), and high-volume injections with
prolonged imaging (a helluva lot).
Angiographic Appearance
Look for abnormalities in the following:
• In the target area.
• Adjacent to drains, surgical clips, and suture lines.
• Extravasation: this will be seen in unstable patients. Ill-defined blush of contrast,
outside of a normal vascular territory, which enlarges and changes morphology
during the angiographic run.
• Pseudoaneursym: focal collection of contrast, outside the confines of the normal
vascular contour. Persists beyond normal arterial washout phase.
• Arteriovenous fistula.
• Vascular injury following central line placement: may visualize occlusion, lumi-
nal irregularity, intraluminal thrombus, spasm, or a dissection flap with tapering
of intraluminal contrast opacification.
Clinical Scenarios
Treatment Plan and Technique
• Try to predict the likely source of the bleeding based on discussion with the
surgical team, the operative note, and pre-procedure imaging.
• Consider and discuss the possible therapeutic options and balance these against
the risks of doing nothing and other therapeutic alternatives.
• Discuss this with the patient/relatives if time allows, including the need to
sacrifice tissues and organs
• Formulate a plan and ideally a backup plan!
• The specific embolic agent depends on the desired permanency of embolization
and the ability to sacrifice downstream supply.
◦ To temporarily stop a rapidly bleeding vessel, Gelfoam pledgets or slurry are
most commonly used.
◦ For permanent occlusion, where downstream flow can be safely sacrificed,
coils, acrylic spheres or large particles may be used.
30 Embolization in Post-operative Hemorrhage 299
Unstable Patients
If the patient is unstable, or if there is rapid hemorrhage, performing the procedure in
a timely fashion is essential. A temporary balloon occlusion may be beneficial either
prior to a return to the operating room or while the definitive embolization procedure is being considered. Therefore, it may be better to non-selectively embolize a
proximal bleeding vessel, rather than perform a lengthy selective embolization. This
can only be accomplished in organs or regions with sufficient collateral flow (e.g.,
proximal internal iliac embolization). In this setting, distal collateral vessels prevent
significant tissue necrosis.
Coagulopathic Patients
Many patients will have an underlying coagulopathy due to ongoing hemorrhage.
Coagulopathies should be aggressively managed, but if the patient remains coagulopathic (e.g., disseminated intravascular coagulopathy), then the embolic agent
used may have to be re-addressed.
• Coils require thombosis; consider combining with Gelfoam to achieve the
vascular occlusion “coil–Gelfoam sandwich.”
• Alternatively, glue can be used as this does not require coagulation to achieve
occlusion.
Active Extravasation
If temporary occlusion is desired, Gelfoam is used (slurry or pledgets). However,
if permanent embolization is needed, then coils or large particles are frequently
utilized.
Pseudoaneurysm
Coils are typically used due to their permanence and precise control in deployment.
Several options exist for occluding a pseudoaneurysm.
• The first, and most frequently used, technique is to “trap” the pseudoaneurysm
by coiling both the upstream and downstream portions of the vessel.
• Alternatively, if anatomically possible (e.g., small neck), a coil can be placed
within the neck of the pseudoaneurysm.
• Some PSA may need to be treated by placing a stent graft across the neck,
particularly if downstream flow cannot be sacrificed.
300 K. Wright and B. English
Iatrogenic Injury During Central Line Placement
Dissection or pseudoaneurysm formation from central line placement generally
requires an operation or endovascular stenting due to the central location of the
arterial injury (e.g., subclavian, carotid artery) and inability to sacrifice downstream flow.
• Avoid burning bridges—if a proximal coil is placed, it will be impossible to
access distal sites later.
• The use of microcatheters may be advantageous to preserve collateral vessels,
but may limit the choice of embolic materials (e.g., large particles and Gelfoam
pledgets).
Post-embolization
• Routine puncture site aftercare
• Consider leaving the arterial sheath in situ if
◦ There is the possibility of further bleeding
◦ There is coagulopathy
Follow-Up
Repeat CT
• This is the key investigation.
• Remember that contrast will remain “trapped” in a thrombosed false aneurysm;
this is a pitfall for the unwary and may lead to false-positive reports of continued perfusion on a contrast-enhanced scan. To prevent this, perform unenhanced
scans first.
• CT may also be compromised by artifact from a large coil pack.
• If there is continued bleeding, remember to look for other potential
sources.
Keypoints
• Post-operative bleeding should be urgently investigated with contrastenhanced CT
• Knowledge of the operation is essential.
• Embolotherapy can be very challenging.
• It is essential to consider all therapeutic options with the surgical team.
30 Embolization in Post-operative Hemorrhage 301
a
c
b
d
Fig. 30.1 Eighty-three-year-old man status post-attempted bedside right internal jugular central
venous catheter placement. (a) Right subclavian angiogram performed approximately 1 week after
attempted line placement demonstrates a moderate-sized pseudoaneurysm arising from the subclavian artery (arrow). Notice the close proximity of the internal mammary artery (open arrow)and
vertebral artery (curved arrow) origins. Due to the lack of a narrow neck (precluding embolization)
and the proximity of the vertebral artery origin (precluding stent-graft placement), no intervention
was performed at this time. Given the patient’s underlying vascular disease and age, sacrificing the
vertebral artery was not considered an optimal result. The patient was placed on anticoagulation,
and serial CT scans (not shown) were performed to follow the progress of the pseudoaneurysm.
(b). Right subclavian angiogram performed 24 days after the initial angiogram demonstrates significant enlargement of the pseudoaneurysm (arrow). Ultrasound of the supraclavicular fossa (not
shown) demonstrated a good window to access the pseudoaneurysm from a percutaneous approach.
(c) Via a right brachial artery approach, an 11-mm occlusion balloon catheter was inflated in the
suclavian artery origin (open arrow), central to the pesudoaneurysm but peripheral to the origin of
the carotid artery. This was performed in an attempt to decrease the risk of non-target embolization
of thrombin during percutaneous injection directly into the pseudoaneurysm. (d) Right subclavian
artery angiogram following ultrasound-guided percutaneous injection of thrombin directly into the
pseudoaneurysm. Angiography demonstrates decreased flow of contrast into the pseudoaneurysm
(arrow) and patency of the cervical vessels. Continued injection of thrombin resulted in complete
occlusion of the pseudoaneurysm
302 K. Wright and B. English
a
c
e.1
b
d
e.2
Fig. 30.2 Fifty-one-year old woman with history of intravenous drug abuse and HIV, who pre-
sented to the emergency department with signs and symptoms of pulmonary embolus. Due to the
lack of venous access, a central line placement was placed in her right femoral vein, after which
she was started on heparin. She developed a right groin hematoma that could not be controlled with
manual compression, and her serum hematocrit dropped from 43 to 25%. (a and b) Angiography
of the right common femoral artery demonstrates a small pool of contrast arising from a branch
of the external pudendal artery (arrows). (c and d) Superselective angiography of the bleeding
external pudendal artery branch redemonstrates bleeding source (arrow). A small amount (1 cc) of
Gelfoam slurry was used to embolize the bleeding branch. Notice how the contrast pool (circle)
enlarges and changes morphology from image to image, confirming the extravascular location of
the contrast
30 Embolization in Post-operative Hemorrhage 303
Safety
• Embolization in the presence of sepsis should be considered a temporizing
measure, as further hemorrhage is likely if there is ongoing infection.
• Embolization may lead to anastomotic dehiscence
• Remember that contrast trapped in thrombus will lead the unwary to
diagnose ongoing bleeding
• Serial blood draws, to ensure the HCT remains stable. If the HCT continues to decrease, a contrast-enhanced CT or additional angiography can be
pursued to assess hemorrhage.
Suggested Reading
Bauer, J.R. and Ray, C.E. (2004). Transcatheter Arterial Embolization in the Trauma Patient: A
Review. Seminars in Interventional Radiology: 2004;21(1):11–22.
Kaufman JA. Vascular Interventions. In Kaufman, JA., Lee, MJ. (eds) Vascular and Interventional
Radiology: The Requisites. Philadelphia: Mosby, 2003:105–113
Ray CE Jr., Waltman AC. General Principles of Embolization and Chemoembolization. In Bakal,
CW., Silberzweig, J., Cynamon, J. (eds). Vascular and Interventional Radiology: Principles and
Practice. New York: Thieme, 2002: 89–100.
Sharafuddin MJ, Sun S, Golzarian J. Embolotherapy: basic principles and applications. In
Golzarian, J., Sun, S., Sharafuddin, MJ. (eds.). Vascular Embolotherapy: A Comprehensive
Approach. Berlin Heidelberg: Springer-Verlag, 2006: 3–14.
Chapter 31
Tract Embolization
George Behrens and Nilesh H. Patel
General Concepts
• Used in various procedures and implies plugging the biopsy or drainage track
using a hemostatic agent (Cowan and Traill 1998; Rosen and Rothberg 1982;
Nakagawa and Nakajima 1994; Shiham and Siddiqi 2005; Allison 1988; Lyon
2006; Riddle and Bilal 2008; Androussi 2005; Schmitz-Rode and Blaum 2000
and Bourgouin and Shepard 1998).
◦ Reduces risk of bleeding.
◦ Reduces risk of bile leak/biloma and urine leak/urinoma.
◦ Reduces risk of pneumothorax.
• Tract embolization is feasible in almost all cases.
• Reduces significantly the risk of hemorrhage in 90–95% of the cases and bile
leaks in liver biopsies.
• Cases have been reported of vascular occlusion as a complication of drainage
track embolization (Cowan and Traill 1998; Rosen and Rothberg 1982;
Nakagawa and Nakajima 1994; Lyon 2006; Riddle and Bilal, 2008 and
Androussi, 2005).
Pre-procedure Evaluation
• Careful patient evaluation is important to determinate risk factors for bleeding.
• Coagulation status, hemoglobin, and hematocrit.
Indications for Tract Embolization
• High probability of bleeding complications.
◦ INR: >1.5
◦ Platelets: <20,000
◦ Von Willbrand’s disease or other known coagulopathy.
Transcatheter Embolization and Therapy,
Techniques in Interventional Radiology, DOI 10.1007/978-1-84800-897-7_31,
C
Springer-Verlag London Limited 2010
305