ACIST Medical Systems announced results from the ACIST-FFR study (Assessment of catheter-based interrogation and standard techniques for fractional flow reserve measurement), which demonstrated—a press release reports—the consistent and correlative performance of the Navvus microcatheter compared to standard pressure wire systems. The study was presented for the first time at EuroPCR 2017 (16–19 May, Paris, France)
This prospective, multicentre study evaluated 245 patients with stable coronary artery disease at 11 US centres. It is assessing the differences in fractional flow reserve (FFR) values obtained using the Navvus microcatheter with those using standard pressure wire systems. Patients’ FFR measurement was obtained by a pressure wire alone and with the microcatheter FFR over the pressure wire. All waveforms and measures were reviewed by an independent FFR core laboratory based upon prespecified criteria for quality measurements.
Of the patients enrolled in the study, 169 had complete data meeting FFR core laboratory criteria. In these patients, an angiographic core lab used quantitative coronary angiography (QCA) to determine a mean reference vessel diameter of 2.8mm, a mean lesion length of 15.3mm, and a mean diameter stenosis of 47%. Unique to this study, 30% of cases included a reference vessel diameter <2.5mm—prior microcatheter FFR clinical studies had only included vessels with reference vessel diameter ≥2.5mm.
The FFR data showed that microcatheter FFR technology offered consistent and modestly lower FFR measurements when compared to a pressure wire, with an average difference of -0.022 (95% CI: -0.029, -0.015). In nearly all of the cases (97%), the differences in FFR measurements did not impact clinical decision-making.
While the mean pressure drift was not different between the pressure wire and the microcatheter (0.015 vs. 0.015, p=0.44), the rate of clinically significant pressure drift was numerically higher with the pressure wire (7.4% vs. 3.5%, p=0.10).
ACIST-FFR co-principal investigator William F Fearon (Stanford University School of Medicine, Stanford Cardiovascular Institute at Stanford University, USA), says: “As the use of FFR in clinical practice continues to grow, it becomes increasingly important to understand the benefits and limitations of each type of FFR technology in regards to delivering consistent measurements and making coronary intervention procedures as efficient as possible.”
The press release states that unlike standard pressure wires, the ACIST RXi rapid exchange FFR Ssystem and Navvus rapid exchange FFR microcatheter allow physicians to use their 0.014” guidewire of choice throughout the procedure—addressing challenges of pressure wires, including accessibility in challenging anatomies, maintaining wire position, pressure‐measurement drift and ease of obtaining post‐intervention FFR.