Not all PFAS are equal — some are essential to medical devices

Per- and polyfluoroalkyl substances, known as PFAS or forever chemicals, are often grouped into a single category; but while certain PFAS are harmful for human and public health, two new articles in the journal Heart Rhythm emphasise that fluoropolymers, a specific class of PFAS, are not considered environmental contaminants and are indispensable for use in medical devices — and should be acknowledged as such.

PFAS are found in products across all sectors of commerce and all parts of the globe, in industries including textiles, aerospace, communications, electronics, pharmaceuticals, energy and health care. Due to their high chemical stability, PFAS are stubbornly persistent in the environment, with certain PFAS having been linked to water contamination, environmental effects and human disease. Two such substances are the water-soluble, small-molecule compounds perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), which are considered environmental contaminants by the US Environmental Protection Agency (EPA).

But study authors Dr Pierce J Vatterott, Dr Paul D Drumheller, Dr Nadine Ding and Dr Joyce Wong noted in their first article that PFAS encompass over 12,000 compounds besides PFOA and PFOS, and fall into distinct classes that have vastly different chemical, biological and toxicological properties. One specific class of PFAS — fluoropolymers — is essential to human and public health, especially to cardiac electrophysiology. Indeed, fluoropolymers are critical in all phases of medical device use, including their manufacturing process, performance, and delivery within the human body.

According to the US Food and Drug Administration (FDA), approximately 250,000 approved medical devices contain fluoropolymers, including cardiac implantable electronic devices, ablation catheters and sheaths. These fluoropolymers undergo extensive biocompatibility and preclinical testing, and have not been linked to health issues associated with their long-term use. Fluoropolymers are also significantly larger than water-soluble PFAS and are not considered environmental contaminants by the EPA.

“At present, no other class of materials exists with fluoropolymers’ unique combined properties including lubricity, biostability, temperature tolerance, strength, flexibility and electrical insulation,” the authors said. “For over 50 years, they have been safely used in medical devices such as brain shunts, cardiac valves, catheters, vascular grafts, pacemakers and defibrillator systems. Fluoropolymers enable minimally invasive procedures, improve long-term device function [and] reliability, and allow significant advancements including device miniaturisation.”

In their second article, the authors highlight key proposed and enacted bans and restrictions, particularly in the US, Canada and the European Union. According to Drumheller, “Many legislations seek to regulate these over 12,000 distinct chemicals as a single class, motivated by the known risks of specific water-soluble, small-molecule compounds, ie, they do not distinguish between toxic water-soluble small-molecule PFAS and medical fluoropolymers.

“These efforts are threatening the availability of fluoropolymers even in cases where medical device exclusions are allowed,” Drumheller stated. Indeed, many PFAS manufacturers are now exiting the medical fluoropolymer market before any regulations take effect, threatening the supply chain for all medical products that use fluoropolymers

“Loss of access to fluoropolymers will have profound negative effects for our patients and on the practice of medicine, especially cardiac electrophysiology,” Vatterott concluded. “It is critical to find a path that protects our environment but ensures the availability of fluoropolymers that are essential in medical devices [and] minimally invasive procedures, and drives ongoing innovation in medical technology.”

Image credit: iStock.com/Jan-Otto