SLIDE 1
Nouveaux liquides
Transcatheter embolization in animal models with GPX, a novel water-borne polymer embolic.
Joshua P. Jones, PhD; Jessica C. Karz; and Matthew S. Johnson, MD, FSIR
Swine Kidney and Liver Embolizations
- All procedures/evaluations were done by non-Fluidx personnel.
- A Boston Scientific Direxion HI-FLO microcatheter (0.027” ID)
was placed proximal to the target vasculature.
- GPX was injected (~0.3 mL) over 1 min. Embozene Microspheres
(40µm) were used as a control (deployed as per the IFU).
- Occlusion was assessed at 15 m and 14 d (see Table 1).
Diverse Use Scenarios
- GPX was deployed into coils at multiple sites including the rete
mirabile as well as the splenic, gastric, and renal arteries.
- In rabbits, elastase was used to create model aneurysms in the
subclavian artery. Embolization was performed using a balloon and jailed catheter technique. Follow-up was performed at 28 d.
- These procedures explored the use of GPX with a variety of
catheters ranging from 0.017” ID (Medtronic Echelon 10) to 0.041” ID (Terumo Glidecath).
GPX (Fluidx Medical Technology, Salt Lake City, UT) is a new type of transcatheter embolic: a water-based coacervate which solidifies upon injection into the
- vasculature. The agent is primarily comprised of two
- ppositely
charged polymers, with interactions shielded by high concentrations of monovalent ions (salt). Tantalum powder is added for radiopacity. Solidification results from strengthened interactions between the
- ppositely
charged polymers in response to decreasing salt concentration (Figure 1). This produces a cohesive viscoelastic gel that can be delivered with control and precision without adhering to catheters. Here, the performance of the GPX embolic was evaluated in procedures out to 14 days in a porcine model and 1 month in a rabbit model. GPX was used alone and in combination with other agents to simulate a variety of clinical scenarios.
Purpose Materials & Methods Results Conclusions
AFA Flow Scale Grade Definition AFA Grade No antegrade flow within the treatment site. AFA Grade 1 Contrast passes into the treatment site but “hangs up” and fails to opacify the entire distal vascular bed. AFA Grade 2 Antegrade filling of contrast with complete filling of the artery and its major and minor branches after more than two cardiac cycles. Alternatively, delayed contrast washout in the target site territory may occur , compared with comparable areas of distal vascular bed not perfused by the target site. AFA Grade 3 Antegrade flow of contrast with complete filling of the vessel and its major and minor branches within two cardiac cycles. Contrast also clears from the arterial segment within two cardiac cycles.Post Injection (0.9% Saline) Coacervate (6-9% Saline) Figure 1: GPX solidifies after delivery in response to decreasing salt concentration. Table 1: The AFA Flow Scale was used to grade
- cclusion at 15 minutes and 14 days.
Swine Kidney and Liver Embolization
- GPX distally penetrated into small arteries
without fragmentation, resulting in immediate occlusion.
- All treatment sites [n=20] showed no flow
(AFA grade 0) at the acute follow-up, compared with an average of 0.7 (+/-0.6) for microspheres [n=4].
- In the survival arm, all sites remained fully
- ccluded
(AFA=0) at 14 days [n=7]. Microspheres had an average AFA score of 2.3 (+/- 1.2) [n=4].
- At necropsy, GPX remained cohesive and
was well distributed in the target tissue. Penetration was seen into small arterioles.
Initial angiogram 15 minutes post 14 days post Faxitron of GPX GPX placementFigure 2: Porcine kidney embolization using GPX at 14 days.
Initial angiogram Coil placement Minimal- cclusion
- cclusion
Figure 3: Diverse uses of
- GPX. Top: With coil. Right:
Acute necropsy. Bottom: Swine rete mirabile (left) and aneurysm model (right).
Initial angiogram GPX embolization No balloon adhesion after embolization of rabbit aneurysmDiverse Use Scenarios
- When injected proximal to coils in
branches of the iliac, splenic, and renal arteries, GPX formed a cohesive embolus that did not travel distal to the coils (Fig. 3).
- In
an acute procedure, GPX demonstrated deep penetration into the rete mirabile, resulting in rapid complete occlusion with no signs
- f
crossing into venous circulation (Fig. 3).
- GPX totally occluded model wide-
neck aneurysms at both acute and 1 month evaluations with no signs
- f
catheter
- r
balloon adhesion. Explanted tissue appeared grossly normal (Fig. 3).
- When
used as a stand-alone embolic, GPX demonstrated good distal penetration, filling down to the arterioles, and generating a stable occlusion.
- In the porcine kidney model, kidney lobes embolized
with GPX had less flow at the acute and long term follow-up than those performed with Embozene Microspheres (40 µm).
- When used in tandem with coils, the cohesiveness of
GPX allows it to form a proximal, complete occlusion without distal migration in different vessel/flow situations.
- GPX is a flow directed embolic agent that appears to
have utility in a variety of embolization scenarios.