Hydrophilic Stent Coating Inhibits Platelet Adhesion on Stent Surfaces: Initial Results In Vitro

Abstract

BackgroundEndovascular stents and flow diverter stents (FDS) have revolutionized the treatment of intradural aneurysms; however, the need for dual anti-platelet treatment (DAPT) limits their use and can cause additional issues. Therefore, there is a need to develop stent coatings that negate the need for DAPT.MethodsTwo different hydrophilic polymer coatings (HPC-I and HPC-II) were used to coat small nickel titanium plates to initially test the hydrophilic properties of these coatings when applied to nickel titanium. The plates were subsequently incubated with non-medicated whole blood from healthy volunteers for 10 min and stained with a CD61 immunofluorescent antibody that allows detection of adherent platelets. The coatings were applied to FDS wires and were again incubated with non-medicated whole blood from the same volunteers. Scanning electron microscopy was used to detect adherent platelets on the wire surface.ResultsThe HPC-II coating (1.12 ± 0.4%) showed a significantly lower CD61 +ve cell count (p ≤ 0.001) compared to both uncoated NiTi plates (48.61 ± 7.3%) and those with the HPC-I coating (mean 40.19 ± 8.9%). Minimal adherent platelets were seen on the FDS nickel titanium wires coated with the HPC-II compared to uncoated FDS under electron microscopy.ConclusionThere is a significant decrease in the number of adherent CD61 +ve platelets on nickel titanium surfaces coated with the HPC-II coating compared to uncoated surfaces. The coating can be successfully applied to the wires of flow diverters. The results of this study are promising with regard to the development of new anti-thrombogenic endovascular devices.

The p48 Flow Modulation Device with Hydrophilic Polymer Coating (HPC) for the Treatment of Acutely Ruptured Aneurysms: Early Clinical Experience Using Single Antiplatelet Therapy

“…pHPC is a glycan-based hydrophilic multilayer polymer coating which can be applied to nitinol surfaces. It is designed to mimic the biological properties of the glycocalyx, the coverage that can be found on the luminal surface of the endothelium of the arterial wall, making the coated surface hydrophilic and, consequently, less thrombogenic [4]. pHPC has no pharmaceutical effect, is biocompatible with no evidence of acute inflammatory response, and does not interact with the physical properties of the metallic implant [10,11].…”

“…The p48MW (phenox, Bochum, Germany) is a new FDS that has been designed to treat distal aneurysms in vessels with diameters of between 1.75 and 3 mm [3]. Its hydrophilic polymer coating (pHPC, phenox, Bochum, Germany) is a novel glycan-based multilayer polymer that has been shown to have significant anti-thrombogenic properties when tested in vitro [4]. A recently published study concluded that the p48MW HPC appears both safe and efficacious under single antiplatelet therapy (SAPT) using prasugrel in selected cases of unruptured aneurysms [5].…”

The p48_HPC antithrombogenic flow diverter: initial human experience using single antiplatelet therapy

“…Analysis of coated versus uncoated p48 flow diverters using scanning electron microscopy demonstrated minimal adherent platelets on the coated flow diverters compared with a thick layer of adherent platelets on uncoated devices. 7 Individual thrombocytes tended to adhere in the vicinity of defects on the wire surface, but large cell agglomerates were not detected. Further studies comparing the p48 with the p48_HPC in a flow model have also been performed.…”

The pCONUS HPC: 30-Day and 180-Day In Vivo Biocompatibility Results

“…We have recently shown that the hydrophilic polymer coating (pHPC, registered trademark of Phenox) has anti-thrombogenic properties when tested in vitro [ 26 ], but there is little known about the in vivo biocompatibility of this coating. The purpose of this study was to determine the acute and chronic biocompatibility of the pHPC coating when applied to the pCONUS device.…”