Transabdominal Direct Sac Puncture Embolization of Type II Endoleaks after Endovascular Abdominal Aortic Aneurysm Repair

Summary

Researchers from the University of Toronto are reporting the experience with type II endoleak repair via a transabdominal direct sac puncture. This is a retrospective review of 30 patients. Inclusion criteria included the presence of safe, unobstructed access from the anterior abdominal wall to the perfused part of the sac, without needing to traverse organs or major intervening arterial structures. Patients without unobstructed access, and patients with isolated IMA endoleak without lumbar artery contribution, were excluded from the study. The authors used US-guidance to access the sac to avoid bowel and adjacent organs/vessels. An 18-gauge trocar needle was used with placement of a hemostatic valve at the hub following sac access. A 2.4 F microcatheter was then placed through the needle and used to select feeding vessels, if able. In treated patients, embolization materials included cyanoacrylate glue (45.5%), glue/coils (36.4%), and Onyx with or without glue/coils (18.1%). Technical success was defined as complete endoleak embolization on fluoro. The primary outcome was freedom from sac growth defined as ≤ 5% sac growth on CT or ≤ 5mm change in sac diameter on US. The team reported a technical success rate in 97% of patients with mean follow-up of 15.5 months. Freedom from sac growth was seen in 85.2% of patients. Complications were seen in only 3 of 33 procedures and included 1 nontarget embolization with transient neuropraxia and 2 self-limiting rectus sheath hematomas. The authors concluded that percutaneous transabdominal embolization is a safe and efficacious treatment for type II endoleak, with a short procedure time.



Fig 1
Ultrasound (a) with Doppler demonstrates an area of endoflow (arrow) in the posterior right of the aneurysm sac, which was (b) subsequently targeted, and a needle was advanced into it under ultrasound guidance, with the needle tip (arrow) positioned within the posterior aspect.



Fig 2
Fluoroscopic image demonstrates (a) a patent IMA (arrow), which was (b) subsequently coil embolized at sac origin to protect the IMA from nontarget embolization (arrow). In addition, a feeding right lumbar artery (arrowhead) and the aneurysm sac (asterisk) were embolized.

Commentary

This manuscript is noteworthy as it effectively shows that transabdominal direct sac puncture can be a safe and effective method for treatment of type II endoleaks. For anyone that is fortunate (or unfortunate) enough to treat type II endoleaks, they will understand well the challenge of treating endoleaks that lack a defined IMA source. Transarterial access into the culprit lumbar vessel(s) is always challenging and often impossible. Further, it is often difficult to prospectively identify patients that will be adequate candidates for a transarterial approach. The present study provides a convincing argument for incorporating transabdominal direct sac access into the treatment algorithm. This approach may not be suitable in all patients secondary to body habitus and need for continuous compression for bowel displacement at time of ultrasound-guided access. However, with a noteworthy 85% freedom from sac growth, it is worth considering in patients with a lumbar source of type II endoleak.

Click here for abstract

Zener R, Oreopoulos G, Beecroft R, Rajan DK, Jaskolka J, Tan KT. Transabdominal direct sac puncture embolization of type II endoleaks after endovascular abdominal aortic aneurysm repair. J Vasc Interv Radiol. 2018; 29: 1167-1173.

Post Author:
Luke R. Wilkins, MD
Assistant Professor
Department of Radiology and Medical Imaging
Section of Vascular and Interventional Radiology
University of Virginia
@LukeWilkins_UVA

Endovascular Removal of Fractured Inferior Vena Cava Filter Fragments: 5-Year Registry Data with Prospective Outcomes on Retained Fragments

Summary

This is a recent review of IVC filter fragment removal from Stanford University by Kuo and his collegues. The study included 82 patients as part of a prospective registry. The investigators reviewed outcomes of residual fragment removal after the main filter was removed. They included fragments that were intravascular per pre-procedure CT, procedural cone beam CT and/or intravascular US. 185 filter fragments were identified excluding the ones lodged in distal pulmonary artery. Eighty-seven of 185 fragments (47%) were deemed amenable to attempted removal: 65 IVC, 11 PA, 8 cardiac, 2 hepatic, and 1 aortic. Authors successfully removed 78 of 87 fragments (89.7%). There were 6 minor complications and 1 major complication (a cardiac tamponade that was successfully treated). Nineteen patients with retained cardiopulmonary fragments, 81% remained asymptomatic during long-term clinical follow-up of 845 days. Authors concluded that percutaneous removal of filter fragments had high technical success rate and low complication rate, except when fragments are intracardiac. Most residual fragments not amenable for retrieval remained asymptomatic and followed clinically.



Figure 3. Images from a 41-year-old patient who presented for complex retrieval of an indwelling Bard Recovery filter (2,505 d). (a,b) Axial and coronal CT images show multifocal filter penetration, with one component penetrating into the aorta (arrows) and fractured within the lumen. (c,d) Spot image of the filter and subsequent cavogram show the extracaval component (arrows). (e) Following main filter body removal, an aortogram also confirms fragment location within the aortic lumen (arrow). (f–h) Fluoroscopic images show successful percutaneous fragment removal via transfemoral arterial access.

Commentary

The paper represents outcomes of attempted and retained filter fragments at a high volume clinically oriented academic interventional radiology practice with a dedicated IVC filter clinic. Of note senior author Dr. Kuo has described first in man utilization of laser for IVC filter removal. IVC filter removal has become an increasing trend during the past 5-10 years fueled by associated law suits related to fracture and migration of filters and broken fragments. As many of us witness commonly, it is not uncommon for existing commercial filters to have broken fragments that migrate into different locations in venous system as well as to extra-venous locations. Unfortunately, there is very limited data on potential complications related to those fragments. This is the first article reviewing a large cohort of filter fragment retrieval. Authors demonstrated that most of intravascular components (confirmed by imaging) can be removed using various techniques at a highly specialized center, but at the same time there were no significant clinical negative outcomes among the filter fragments that were left behind.

After review of this manuscript and through personal experience I would recommend retrieval of intravascular fragments especially if they have the risk for eventual migration to the heart. Intracardiac fragments carry higher risk of complication during retrieval but they also pose higher risk of complications when left alone (cardiac tamponade, arrhythmias, etc). Again, when feasible with cardiac surgery support these fragments should be managed at experienced centers. Low risk fragments can be monitored with imaging and confirm stability. Thanks to the authors for providing guidance in this difficult topic.

Click here for abstract

Andrew J. Kesselman, MD, Nam Sao Hoang, BA, Alexander Y. Sheu, MD, and William T. Kuo, MD Endovascular Removal of Fractured Inferior Vena Cava Filter Fragments: 5-Year Registry Data with Prospective Outcomes on Retained Fragments J Vasc Interv Radiol. 2018 Jun;29(6):758-764. doi: 10.1016/j.jvir.2018.01.786. Epub 2018 Apr 26.

Post Author:
Bulent Arslan, MD, FSIR
Associate Professor and Associate Chair of Radiology
Division Director, Vascular and Interventional Radiology
Department of Radiology and Nuclear Medicine
Rush University Medical Center
Chicago, IL
@arslanmd

Quantification of combined effects of transarterial embolization and microwave ablation 

Summary

Combining percutaneous ablation and transarterial embolization for treatment of tumors, including hepatocellular carcinoma (HCC), has been of interest for some time. Although each are effective as monotherapy, improved oncologic outcomes can theoretically be achieved when combining the therapies, especially if the tumor is large or infiltrative. It stands to reason that if the cooling effect from hepatic arterial blood flow can be decreased by first performing an arterial embolization, then ablation efficacy can be improved.

Researchers from Mayo Clinic in Rochester and University of Wisconsin-Madison recently published their results quantifying the effect of embolization on microwave ablation (MW) in an in vivo porcine liver model. They studied the effects of combined MW ablation and embolization in 6 swine. Hepatic artery catheterization was performed in each animal and embolization of 2 of the 4 liver lobes was performed using 100-300 um trisacryl gelatin microspheres. MW ablations were then done in an open manner within each liver lobe immediately after embolization using a 2.45-GHz system and single 17- gauge antenna. They performed cone-beam CT at short intervals during ablation to evaluate gas formation. Diameter, length, area and circularity of ablation zones were measured on gross tissue sections and microscopic and histologic evaluation of both embolized and nonembolized tissue sections performed. They found that the embolization/MW ablation zones had a significantly greater area (mean ± standard deviation, 11.8 cm2 ± 2.5), length (4.8 cm ± 0.5), and diameter (3.1 cm ± 0.6) compared with MW ablation alone (7.1 cm2 ± 1.9, 3.7 cm ± 0.6, 2.4 cm ± 0.3, respectively). CT showed faster and greater gas formation around the antennae in the embolized lobes. Both groups showed a central charred zone and a peripheral zone of noncharred coagulated tissue. However, only the MW group showed a hemorrhagic zone beyond the noncharred coagulated zone. It was this noncharred zone that was responsible for the larger size of the ablation zone in the embolization/MW ablation group (1.3 cm ± 0.4 vs 0.8 cm ± 0.2).



Figure. Gross pathologic specimens demonstrate increased size of the embolization/MW ablation zone (a) compared with MW ablation only (b). The increased size of the ablation zone was predominantly the result of a wider peripheral noncharred coagulative zone (asterisks). The charred central portion (triangles) was not significantly different between the groups (P 1⁄4 .2611).

Commentary

While other studies have shown the clinical benefits of combining transarterial embolization with ablation, the effects have not been well quantified. This study is a step towards gaining an understanding of how combining these therapies influences the ablation zone-embolizing first can be theorized to promote coagulation in tissue that otherwise may not be affected due to persistent arterial flow-and hopefully, ultimately, allowing one to predict the enhanced ablation zone when this technique is utilized. Of course, more studies are necessary to determine whether combination therapy has the same effect on the ablation zone in tumoral, cirrhotic livers and also whether chemoembolization makes a difference.

Click here for abstract

Knavel EM, Green CM, Gendron-Fitzpatrick A, Brace CL, Laeseke PF. Combination Therapies: Quantifying the Effects of Transarterial Embolization on Microwave Ablation Zones. Journal of vascular and interventional radiology : JVIR. 2018;29:1050-1056.

Post Author
Zagum Bhatti, MD
Assistant Professor
Department of Radiology, Interventional Radiology Division
University of Texas Health Science Center at Houston, Houston, TX
@UTHouston_IR
@ZagumBhatti