In Vitro Evaluation of Coating Performance of Guidewire Surrogates Free

Vascular guidewires are commonly used during interventional surgery to help introduce and position intravascular catheters at the treatment site. Nitinol (NiTi) and stainless steel are the most commonly used alloys in guidewires and a thin layer of polymer coating is usually applied on the guidewire surface to reduce friction within the lumen of blood vessels. Hydrophobic (e.g. PTFE) or hydrophilic (e.g., hyaluronic acid (HA), polyvinylpyrrolidone (PVP), etc.) coatings may be used for this purpose, but coating separation/flaking has been reported from intravascular medical devices [1]. Coating fragments may cause serious adverse events in patients, including pulmonary embolism and infarction, myocardial embolism, necrosis, and death. Hydrophilic polymer emboli in patients has also been reported [2][3][4]. By 2015, the Environmental Protection Agency (EPA) required device manufacturers to phase out the use of the surfactant, perfluorooctanoic acid (PFOA), a potential carcinogen during polytetrafluoroethylene (PTFE) coating manufacturing [5]. Such changes in manufacturing processes need to be evaluated for their effects on coating performance. Of special concern is flaking of coatings, a multifactorial phenomenon that may be related to changes in device design, manufacturing, pre-conditioning, storage, and/or clinical use. There is no comprehensive standard for assessment of coating performance on guidewires. The objective of this study was to evaluate hydrophilic coating integrity and durability during in vitro soaking and bending stress tests.