Precipitating hydrophobic injectable liquid embolization of intracranial vascular shunts: initial experience and technical note

Abstract

Precipitating hydrophobic injectable liquid (PHIL) is a newly available liquid embolic agent for endovascular therapy. It is nonadhesive and composed of a biocompatible polymer dissolved in dimethyl sulfoxide solvent and bonded covalently with iodine. In this report, the authors present their preliminary experience using PHIL in the treatment of intracranial vascular shunts. Between July 2015 and December 2015, 11 patients underwent endovascular embolization using the PHIL embolic agent. Five patients had arteriovenous malformations, 4 had dural arteriovenous fistulas, 1 patient had a carotid-cavernous fistula, and 1 patient had a pial arteriovenous fistula. Clinical features, angioarchitectural characteristics, procedural details, and periprocedural complications were included in the analysis. Complete or near-complete obliteration of the nidus or fistulas was achieved in 8 of these patients. Partial embolization (approximately 80% in 2 and 30% in 1) was attained in the other 3 patients. Satisfactory venous penetration after nidal embolization was achieved in all patients. In 1 patient, the microcatheter could not be retrieved. No other major complications related to PHIL injection were noted during the procedure or periprocedural period. Clinical follow-up ranging from 8 months to 1 year showed good outcomes in all but 1 patient, who experienced an intraventricular hemorrhage 6 weeks after embolization. PHIL appears to be an effective alternative embolic material with certain advantages over other available liquid embolic agents. Further studies with adequate follow-up are required to fully evaluate its safety and efficacy.

Long Vascular Sheaths for Transfemoral Neuroendovascular Procedures in Children

“…Arteriovenous intracranial shunting lesions are challenging lesions, mandating careful technical nuance that is made easier by dual microcatheter technique to enable optimal nidal penetration while avoiding nontarget embolization and reflux of liquid embolic agent. Several recent technical advancements, predominantly described in the adult literature, including microballoon assistance, 4 use of newer liquid embolic agents like Onyx and precipitating hydrophobic injectable liquid (PHIL), 5,6 and pressure cooker technique, 7 all of which have been shown to increase the efficacy and safety of endovascular treatment, have a limited role with a single 4 Fr access that is traditionally employed in children. 8 Similarly, treatment of pial arteriovenous fistula (AVF) and fistulous points of nidal AVMs have been thus far dependent on carefully controlled injections of n-butyl cyanoacrylate, [9][10][11][12] which although effective, have a significant risk profile.…”

In vivo evaluation of the new PHIL low viscosity in a swine rete mirabile model

“…The microcatheter or balloon distal markers can easily be seen even within large embolization casts (Figure 1). 3 Precise localization of the microcatheter/balloon tip during embolization facilitates reflux control, assessment of venous penetration and nidal embolization in treatment of AVMs and complex arteriovenous fistulas. 2,9 Gentric et al also described their experience with PHIL and Onyx 18 in embolizing swine rete.…”

“…PHIL (25, 30 and 35) has been used in the embolization of arteriovenous malformations (AVMs) and arteriovenous fistulas, among others. [1][2][3] Initial experience in these clinical scenarios has demonstrated its safety and effectiveness.…”

Advocating Intraluminal Radiation Therapy in Cerebral Arteriovenous Malformation Treatment

“…Triiodophenol is used as an iodine component, being covalently bound to the copolymer for radiopacity [72]. Initial studies show embolization characteristics, embolization extent, and biocompatibility to be comparable with those of Onyx [72][73][74]. However, further studies are required to fully evaluate its safety and efficacy [74].…”

“…Initial studies show embolization characteristics, embolization extent, and biocompatibility to be comparable with those of Onyx [72][73][74]. However, further studies are required to fully evaluate its safety and efficacy [74]. PHIL main advantages are: shorter pause times that result in significantly higher embolization success compared with Onyx; lower volumes required for the same extent of embolization compared with Onyx; it comes ready for use (does not require preliminary preparation); and improved visibility compared with Onyx.…”