Purpose: The choice of an embolic agent for an application depends on desired clinical endpoints. GPX is a radiopaque, permanent liquid embolic that does not rely on precipitation from DMSO or in situ polymerization. The purpose of this study was to examine handling characteristics, occlusion properties, and histological response in a chronic animal study using the preclinical GPX Embolic Device and several comparisons.
Material and Methods: In 10 swine, standard endovascular technique was used to introduce a microcatheter into the target site. Embolization was performed in a single pole of each kidney and in two distinct arterial sites in the liver. In addition to GPX, NBCA, Onyx-34, PVA-200, and coils were used as comparisons. Flow was monitored before and after embolization using the AFA flow scale. Handling and performance attributes were assessed on a semi-quantitative (1-5) scale. Post-procedure blood chemistry and clinical signs were monitored. Angiograms were performed prior to termination at 30 or 90 days (5 pigs each). In a small pilot study (2 pigs), a percutaneous transhepatic approach was used to embolize the portal vein with GPX.
Results: All embolizations achieved stasis initially (AFA=0). In the physician survey, liquids rated similar in radiographic visualization and ability to occlude, but GPX achieved higher scores in ease of prep and ease of delivery, which were statistically significant. No abnormalities in blood chemistry were found following the procedure. At 30 and 90 days, all sites embolized with GPX (12) remained occluded (AFA=0) with no device migration. The portal vein also remained occluded at 30 days. Some partial angiographic recanalization (AFA=1 or 2) was observed with coils (5/6), Onyx (2/5), PVA (5/6) and NBCA (1/7). Necropsy revealed hard infarcts in the areas embolized with GPX, consistent with the angiography. No adverse effects from the devices were seen. Histopathology will be presented.
Conclusions: GPX was rated highly in ease of preparation and delivery. Furthermore, no recanalization was seen at 30 and 90 days while at least one partial recanalization was seen with NBCA, Onyx, PVA, and coils. Additional studies and clinical experience are needed to validate this finding.