Intracranial Stenting without Dual Antiaggregation; Reduced Thrombogenicity due to Hydrophilic Coating with pHPC - Concept and Clinical Application

Intracranial stenting is relevant for the treatment of atherosclerotic stenoses and aneurysms. Stents and stent derivates (e.g., flow diverters) are thrombogenic. In order to avoid thromboembolic complications, dual antiplatelet therapy (DAPT; e.g., ASA plus clopidogrel) is required. Related issues include insufficient platelet function inhibition due to non-responder status of the patient with thromboembolic sequelae, hemorrhagic complications of surgical procedures under DAPT, and hyperresponse under standard DAPT dosage. Replacing DAPT in the context of intracranial stent implantation by single antiplatelet therapy (SAPT) is a promising concept, but requires implants with a significantly reduced thrombogenicity.

Several substances were evaluated in vitro and in vivo as candidates for a surface coating. A glycan-based nano-coating which simulates the glycocalix was found efficacious and safe (i.e., biocompatible) and was further developed to pHPC (phenox, Bochum, Germany). This is a hydrophilic coating, which is reducing significantly the thrombogenicity of self-expanding intracranial stents and flow diverters made from nitinol. In vitro testing included the demonstration of increased surface hydrophilicity of coated devices. In vivo tests were focussed on the histocompatibility of pHPC.

Low profile flow diverters (p48_HPC), low porosity flow diverters (p64_HPC) and bifurcation stents (pCONUS_HPC; all phenox) were developed and used clinically. It has been shown that these neurovascular devices can be implanted under DAPT and SAPT as well. ASA or prasugrel in standard dosages have been used for SAPT. Various clinical trials are underway to further evaluate the safety and efficacy of this novel coating under SAPT.