K.E.M. Radiology

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Department of Radiology 

  Seth G.S. Medical College and K.E.M. Hospital, Mumbai , India

Interventional Case Record

< Case 38 : September 2023 >

Treatment of an intragenic pseudoaneurysm of the external lilac artery using a covered stent

 Contributed by : Salman Mapara

Introduction:

Pseudoaneurysms occurs due to a disruption in an arterial wall. The high-pressure arterial blood stretches the weakened arterial wall and creates a communicating sac within the lumen of the artery. The sac is surrounded by the adventitia and media of the vessel. There are many causes of pseudoaneurysms with the most common being due to inflammation, iatrogenic surgical or catheterization injuries, and trauma.  It is also important to note that patients with pseudoaneurysms have common symptoms including - but are not limited to - pain, swelling, pulsatile mass, and symptoms associated with nerve and vein compression, such as venous thrombosis and neuropathy. Of the sites in which pseudoaneurysms can be found, those supplied by the external and internal iliac artery, specifically the external are relatively rare. [1, 2, 3]

Because pseudoaneurysms can be fatal, it is important to maintain the diagnostic possibility of a pseudoaneurysm in patients who have had prior history of trauma to the area along with complaints of pain, nerve compression, and loss of mobility in the corresponding limb. We present a case of a middle-aged woman with a medium sized lobular pseudoaneurysm arising from the mid part of right external iliac artery secondary to right sided hemicolectomy for neuroendocrine tumor of caecal region.

Case presentation: 

 A 45-year-old woman was referred to us with a gradually increasing, pulsatile swelling in the right lower quadrant of the abdomen. The patient complained of  pain in the right thigh region. She was post operative Day 8 case - following  right hemicolectomy for an neuroendocrine tumor of caecal region. Her pulse rate was 115 per minute and the blood pressure was 110/70mm of Hg. The Hb was 7.0; Platelets- 1, 40,000; S. Creatinine- 0.8. The patient was given blood transfusions. After hemodynamic stabilization, the patient underwent CT Angiography of abdomen and pelvis.

             Computed Tomography of abdomen and pelvis showed a well-defined multilobulated complex pseudoaneurysm with medial and lateral components with respect to right external iliac artery (EIA). The medial component of pseudoaneurysm located lateral to SFA measured approximately 2.6 x2.4 x 2.2 cm arose from mid EIA with a wide neck along medial wall of right EIA. (Figure 1c) A tortuous contrast filling outpouching was seen arising from it. (Figure 1a and 1b) 

           

 Figure 1a and 1b—axial and coronal CT arterial phase angiogram images showing lobular pseudoaneurysm arising from mid part of right external iliac artery (EIA).

Figure 1c—CT pelvic angiogram volume rendered 3D images showing pseudoaneurysm in relation to right EIA

Under aseptic precaution,  and local anaesthesia, a left transfemoral arterial access was obtained using a 8F sheath. A 4F pigtail catheter was used to obtain a pelvic angiogram, This confirmed the findings on the CT scan. There was a with a pseudoaneurysm in right external iliac artery (EIA). (Figure 2a). Further selective angiogram was performed using cobra catheter which showed a large multilobulated complex pseudoaneurysm arising from right EIA.  (figure 2b 2c and 2d). 


Figure 2a, 2b, 2c and 2d --- DSA angiogram images of pelvic region showing right EIA pseudoaneurysm-

Figure 2a—pigtail angiogram of pelvis

Figure 2b- cobra catheter selective angiogram of right CIA, 

Figure 2c-- showing balkin catheter angiogram and 

Figure 2d-- showing marker pigtail measurement of pseudoaneurysm segment of right EIA.

Interventional Technique:

Using an AES wire, a short sheath was exchanged with 8Fr Balkin crossover sheath. A BARD Covera stent graft (7 x 80 mm) was deployed over the AES wire. The post-stenting angiogram (figure 4a and 4b) showed good antegrade flow across the stent and a complete pelvic angiogram was performed and normal flow was seendistally. (Figure 3a and 3b). The aneurysms did not opacify. 

Figure 3a and 3b- showing DSA images and inverted fluoroscopic x ray image showing deployed stent graft in right external iliac artery (EIA)



Figure 4a and 4b- showing DSA angiogram images showing angiogram from deployed stent graft in right external iliac artery (EIA) with good flow across and distal segments and complete occlusion of the pseudoaneurysm.

Figure 5a and 5b- showing CT Pelvic angiogram images in coronal and sagittal sections showing deployed stent graft in right external iliac artery (EIA) with good flow across and distal segments and complete occlusion of the pseudoaneurysm.

Discussion:

Penetrating trauma to vessel wall, whether iatrogenic, or accidental can lead to damage of the arterial wall with formation of a pseudoaneurysm and if there is a communication with the adjacent vein, an arteriovenous fistula. [1] CT and MR imaging play an essential role in the diagnosis of extremity pseudoaneurysms and AVF, however, in most cases conventional angiography is still required for accurate lesion localization and tailoring of the surgical or endovascular treatment. [4,5]

          Recent improvements in endovascular techniques have created significant and effective alternatives to surgical treatment. Metallic coils and covered stent implantations are being utilized frequently for endovascular treatment of AVFs. [6,7,8,9] With the significant improvement in stent technology in the last decade, utilization of covered stents for traumatic AVFs and pseudo aneurysms is becoming quite popular. Using covered stents for treating AVFs is technically easy and it has been reported to have a high technical success rate and a low complication rate in various arteries in different series of literature [6,2]

           Covered Stent is an expandable, flexible, metal (nitinol) tube-shaped device (stent) that is covered with a material called expanded polytetrafluoroethylene (ePTFE). With the significant improvement in stent technology in the last decade, utilization of covered stents for traumatic AVFs and pseudo aneurysms is becoming quite popular [5,6,8]. Using covered stents for treating AVFs is technically easy and it has been reported to have a high technical success rate and a low complication rate in various arteries in different series of literature in a superficial or endoluminally inaccessible artery, management of pseudoaneurysms will include options like direct coil embolization, thrombin injection or direct glue injection. 

           In an endoluminally accessible artery, the choice depends on whether the artery is expendable or not. If expendable, the artery can be embolized, however, in addition, distal embolization might be needed if there is retrograde filling into the sac. In an inexpendable artery, options available are aneurysm embolization if neck is narrow or stent graft placement if wide necked.

Endoluminal management serves to exclude a pseudoaneurysm from the circulation. Selecting the optimal method depends on the size of the pseudoaneurysmal neck and the expendability of the donor artery. [10] Exclusion methods fall into two broad categories: embolization and stent placement. A pseudoaneurysm arising from an inexpendable artery must be excluded from the circulation while preserving the circulation in the involved vessel. The width of the pseudoaneurysmal neck relative to the diameter of the donor artery is the determining factor for the selection of method of therapy. If the neck is narrow, the pseudoaneurysm may be embolized with catheter-directed delivery of coils (the preferred embolization material) into the sac itself made of either stainless steel or platinum. Polyester fibres are incorporated into the body of the coil to increase its thrombogenicity which conform to the shape of and fill the pseudoaneurysmal sac. The disadvantage of using coils as an embolization material is the potential for recanalization of the embolized sac if the coils are not tightly packed. [9.10]

          Stent-graft placement requires a higher profile and a stiffer delivery system than does catheter-directed coil embolization. As a result, the arterial anatomy and the calibre of the arteries leading to and at the pseudoaneurysm site should be favourable (i.e., reduced arterial tortuosity and large diameter arteries). An additional reason for placing stent-grafts only in larger arteries is that in small arteries they pose a higher risk of thrombosis or significant vascular stenosis. [9,10]

Conclusion:

        In our case of itragenic traumatic pseudo aneurysms, stent graft was deployed to treat the complex pseudo aneurysm arising from the right EIA. The procedure yielded good result seen in the form of reduced swelling and cessation of leakage from it. Clinically suggestive of no hematoma and hemodynamic stability. Thus, stent graft can be deployed successfully in acute traumatic pseudoaneurysms yielding better results than open repair.


References:

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3. Kubal C, Cacciola R, Riley P, Ready A. Internal iliac artery pseudoaneurysm following renal transplant biopsy successfully treated with endovascular stenting and thrombosis: a case report. Transplant Proc. 2007;39(5):1676-1678.         

4. Johnson CA. Endovascular management of peripheral vascular trauma. Semin. Intervent. Radiol. 2010; 27: 38– 43.

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8. DuBose JJ, Savage SA, Fabian TC et al. The American Association for the Surgery of Trauma prospective Observational Vascular Injury Treatment (PROOVIT) registry: multicenter data on modern vascular injury diagnosis, management, and outcomes. J. Trauma Acute Care Surg. 2015; 78: 215– 23.

9. Stewart DK, Brown PM, Tinsley EA Jr, Hope WW, Clancy TV. Use of stent grafts in lower extremity trauma. Ann. Vasc. Surg. 2011; 25: 264– e9.

10. Simmons JD, Walker WB, Gunter Iii JW, Ahmed N. Role of endovascular grafts in combined vascular and skeletal injuries of the lower extremity: a preliminary report. Arch. Trauma Res. 2013; 2: 40–45