Safety and Efficacy of Peripheral Embolization with EASYX Liquid Embolic Agent: A Multicenter Prospective Study

Clinical question
Is EASYX, a new non-adhesive precipitating liquid embolic agent based on a polyvinyl alcohol ether polymer labeled with iodine molecules, safe and effective for peripheral embolization.

Take away point
EASYX is a novel copolymer liquid embolic agent that is safe and effective for peripheral embolization. The absence of tantalum allowed reduced CT artifacts on imaging follow-up, which was especially useful in patients with type II endoleaks.

Reference
Sapoval M., Vidal V., Dean C., Del Giudice C., Tradi F., Chevallier O., Charles-Nelson A., Pellerin O., Loffroy. Safety and Efficacy of Peripheral Embolization with EASYX Liquid Embolic Agent: A Multicenter Prospective Study. J Vasc Interv Radiol. 2021 Aug; 32 (8): 1136-1143

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Study design
Prospective, observational analysis of embolization using EASYX on a range of indications including varicoceles, type II endoleaks, portal vein embolization before hepatectomy (PVE), acute arterial hemorrhage, and angiomyolipomas (AML).

Funding Source
The study was funded by a grant from Antia Therapeutics and Qmedics. The study was sponsored by Assistance Publique-Hôpitaux de Paris.

Setting
Academic setting. AP-HP - Hopital Europeen Georges-Pompidou Paris, France, Paris, Ile-de-France, France

Figure

Figure. Cone-beam computed tomography of the gonadal vein after previous coil embolization and re-embolization with EASYX. The gonadal vein was 100% occluded and because EASYX contains no tantalum, no beam artifacts were seen, comparing favorably to the artifact around the metallic coils that had been previously implanted.

Summary

EASYX liquid embolic is a new liquid embolic rendered radiopaque by iodine bound to the polymer backbone, thus minimizing beam-hardening artifacts on follow-up imaging associated with liquid embolics containing micronized tantalum as the radiopaque agent. Research of EASYX in a porcine model reported effective embolization without safety/technical issues; however, studies using humans have not been reported. The authors performed a multicenter, prospective, open label phase 2 study at 3 centers in France to assess the safety and efficacy of EASYX use in humans with a range of indications. A total of 8 interventional radiologists used the device for the study purpose, and embolization was performed according to the SIR guidelines for percutaneous transcatheter embolization for each indication. Statistical analysis used quantitative variables expressed as mean ± SD and range, and qualitative variables expressed as raw numbers (n) and proportion and percentages (%). Also, mean of variables before and after the procedure were compared using the paired Mann-Whitney U test.

The efficacy primary endpoint was the percentage of clinical success depending on the indication: target vessel occlusion (arterial hemorrhage), stability or reduction of the aneurysm maximal diameters on CT at 6 months compared to baseline (type II endoleak), growth of future liver remnant by >15% on presurgical CT compared with baseline (portal vein embolization), absence of reflux on ultrasound Doppler at 1 month (varicocele embolization), and >10% reduction of at least 1 diameter on MR or CT at 3 months compared with baseline (angiomyolipoma).

The primary safety endpoint was the expected and unexpected per-procedure serious adverse events related to the EASYX as adjudicated by an independent Critical Events Committee. A total of 3 major device related complications occurred in 2 patients:

• Non-target embolization in a patient with acute hemorrhage related to pseudoaneurysm in which distal coil protection was contraindicated due to a history of Ehlers-Danlos syndrome. 
• Non-target embolization and acute kidney failure in a patient referred for AML embolization which led to complete occlusion of the renal artery.

As for secondary endpoints, 6 patients died before the last study visit (6 months), all deaths adjudicated as the normal evolution of the index illness. The mean pain score was 0.5 ± 1.41 (range, 0–4) for type II endoleaks, 1.6 ± 2.59 (range, 0–8) for active bleeding, and 5.03 ± 2.11 (range, 2–8) for varicocele, assessed using a 0 to 10 visual analog scale in patients under local anesthesia. The satisfaction of the interventional radiologists was >90% for EASYX ease of use, ease of injection, cohesivity, and overall angiographic results.

There was reported operator dissatisfaction with fluoroscopic visibility compared to other ethylene vinyl alcohol-based agents; however, there was significantly less streak artifact on subsequent CT scans. Also, a higher rate of varicocele recurrence was reported, although no associated inflammatory responses were reported, as compared to sclerosants and coils. Overall, the above results demonstrate high user satisfaction and relatively low complications.

Commentary

The authors of this study describe EASYX as both safe and effective for embolization in human subjects for a variety of indications via positive primary and secondary endpoints. The heterogeneous nature of the procedures included introduces bias. Additional limitations include the small number of patients in some indications and short-term follow-up. However, the study provides support for a phase two study as EASYX was generally safe with few complications, easy to use, and effective for its indications. Future direct comparison of EASYX to standard embolics is necessary to establish its clinical value. Additionally, longer term follow-up and larger sample size in future studies will be needed.

Post Author
Colin Marshall, D.O.
PGY-3 Diagnostic Radiology Residency
University Hospitals Cleveland Medical Center
@colinradsIR

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