Visceral Artery Aneurysm and Pseudo Aneurysm

Visceral artery aneurysms (VAAs) and pseudoaneurysms are critical vascular conditions characterized by weakened or damaged blood vessel walls within the abdomen. VAAs represent a dilation or ballooning of these arteries, while pseudoaneurysms result from a breach in the vessel wall, often as a consequence of trauma or surgical interventions. Both conditions can lead to life-threatening complications if left untreated. Prompt diagnosis and intervention are crucial in managing these potentially hazardous vascular anomalies.

Patient Preparation:

Parameter	Requirements/Considerations
Size of pseudoaneurysm & its neck	1. Large size–option of percutaneous approach 2. Wide neck–risk of non target embolization
Coagulation Parameters	Prothrombin Time, INR, Platelet Count
Anti-hypertensive Medication	Morning dose (mandatory for hypertensive patients)
Parent Artery	1. End artery vs. artery with rich collaterals – proximal occlusion vs. sandwich embolization 2. Expendable vs. inexpendable artery – parent artery occlusion vs. preservation approaches 3. Tortuous artery – difficult catheterization; consider other approaches
Location	1. Proximal – short landing zone poses difficulty
Informed Consent	Obtain consent from patients
Anesthesia	Local anesthesia (for most procedures)

Embolic Agents Used:

Agent	Form	Mixing Solution	Concentration (IU/mL)	Mechanism of Action	Advantages	Disadvantages
Gelatin Sponge	Sheets/Powder	Iodinated Contrast Med	N/A	Mechanical Obstruction	Low Cost, Emergency Control of Bleeding	Non-target Embolization, Infection, Chance of Re-Bleed
Amplatzer Vascular Plug	Nitinol Mesh	N/A	N/A	Mechanical Occlusion	High Success Rates Pseudoaneurysms arising from medium-sized vessels.	High Initial Cost (vs. Coil), May Require Oversizing (30-50%)
Coils	Metal	N/A	N/A	Mechanical Obstruction, Thrombosis	1. Most commonly used technique for VAAs 2. Fibered coils more thrombogenic 3. Proper sizing critical (exceed vessel lumen by 20%) 4. High Success Rates 5. Different Techniques	Risk of Non-Target Embolization, Migration
Glue	Liquid	Lipiodol	N/A	Polymerization, Thrombosis	Useful in Tortuous Arteries, Recurrent Cases	Higher Risk of Complications (Use with Caution)
Thrombin	Lyophilized	Calcium Chloride	2500-10000	Activation of Coagulation Cascade	Direct Percutaneous Embolization	Allergy, Local Infection
Thrombin			100-1000	Activates Coagulation Cascade	Direct Percutaneous Embolization	Allergy, Local Infection

Embolization Techniques used:

Technique	Description	Suitable Pseudoaneurysms	Advantages	Disadvantages
Sac Packing	Filling the aneurysm with coils or microcoils.	Saccular pseudoaneurysms with narrow neck.	High packing (80-90%) density occludes the neck.	Risk of secondary rupture (rare).
Sandwich Technique	Occluding the pseudoaneurysm neck and both inflow and outflow collateral vessels.	Pseudoaneurysms likely to have collateral inflow vessels. -Splenic A -Hepatic A -GDA	Prevents incomplete embolization by occlusion of both efferent (back door) and afferent artery (front door)	Requires careful planning.
Proximal Occlusion	Occluding the proximal inflow artery (generally performed for end arteries). - Branch of Renal A	Pseudoaneurysms with wide neck in end arteries.	Preserves patency of parent artery.	Limited to end arteries
Stent Graft	Placing a covered stent across the aneurysm neck.	Larger proximal arterial segments.	Maintains patency of parent artery.	Cannot pass through tortuous arteries.
Stent Assisted Coiling	Using a stent or balloon to assist coil placement.	Used in wide neck saccular aneurysms	Uncovered stent to preserve vessel flow	Requires expandable parent artery.
Balloon Remodelling	Placing a balloon across the aneurysm neck.	Employed in wide neck saccular aneurysms	Microcatheter within aneurysm, parallel balloon inflated to prevent coil migration	Requires expandable parent artery.
Flow Diverting Stents	Using multi-layered bare stents to slow blood flow within the pseudoaneurysm.	Limited use in pseudoaneurysms.	Maintains patency of parent artery, high thrombosis rate.	Suitable for aneurysms with multiple side branches and complex anatomies

Approaches for Treatment of Visceral Artery Pseudoaneurysm:

Approach	Indications	Advantages	Disadvantages
Endovascular	Most cases	Better definition of vascular anatomy and hemodynamics	Difficulty in Catheterization Short Landing Zone
Percutaneous	Pseudoaneurysms with narrow neck	Useful for pseudoaneurysms surrounded by solid organs or large superficial pseudoaneurysm	Requires Ultrasonography/CT guidane

Complications of Visceral Artery Pseudoaneurysm Embolization:

Complication	Description	Management
Puncture Site Complications	Complications at the site of arterial puncture.	- Bleeding: Local compression, resuscitation, balloon placement (if necessary). - Hematoma: Observation or drainage if large. - Pseudoaneurysm Formation: Ultrasound-guided manual compression or thrombin injection. - Arterial Thrombosis: Thrombolysis or thrombectomy if necessary. - Arterio-Venous Fistula: Observation or endovascular repair if symptomatic. - Nerve Damage: Observation or intervention based on severity.
Intervention Site Complications	Complications related to the embolization procedure itself.	- Rupture of Pseudoaneurysm: Immediate control of bleeding, possible endovascular or surgical intervention if unstable. - Arterial Dissection: Heparinized saline infusion, stenting if major artery involved. - Non-Target Embolization: Expectant management, possible intervention if end organ damage. - Coil Migration: Observation or possible intervention if symptomatic. - Straight Deployment of Coil: Observation or possible intervention if symptomatic.
Post-Embolization Complications	Complications that may arise after the embolization procedure.	- Secondary Infection: Observation or intervention based on severity. - Embolization Syndrome (Pain, Fever, Vomiting): Supportive care and symptomatic management.

References