Study Evaluates Performance of Acist's Navvus Microcatheter for FFR
May 17, 2017—Acist Medical Systems Inc., a Bracco Group Company, announced results from the ACIST-FFR study demonstrating the consistent and correlative performance of the company's Navvus microcatheter compared with standard pressure wire fractional flow reserve (FFR) systems. The multicenter ACIST-FFR study includes multiple pressure wire comparators. The ACIST-FFR study findings were presented for the first time by Coprincipal Investigator Matthew Price, MD, at the EuroPCR 2017 conference in Paris, France.
According to the company, this prospective, multicenter study evaluated 245 patients with stable coronary artery disease at 11 centers in the United States. Investigators assessed the differences in FFR values obtained using the Navvus microcatheter compared with those using standard pressure wire FFR systems. The 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 on 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 to determine a mean reference vessel diameter (RVD) of 2.8 mm, a mean lesion length of 15.3 mm, and a mean diameter stenosis of 47%. In addition, 30% of cases in this study included an RVD < 2.5 mm; previous microcatheter FFR clinical studies had only included vessels with RVD ≥ 2.5 mm, noted the company.
Acist stated that 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% confidence interval, -0.029 to -0.015). In 97% of the cases, the differences in FFR measurements did not impact clinical decision making.
Although the mean pressure drift was not different between the pressure wire and the microcatheter (0.015 vs 0.015; P = .44), the rate of clinically significant pressure drift was numerically higher with the pressure wire (7.4% vs 3.5%; P = .1).
The company noted that unlike standard pressure wires, the Acist RXi rapid exchange FFR system and Navvus rapid exchange FFR microcatheter allow physicians to use their 0.014-inch 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 postintervention FFR.
ACIST-FFR Coprincipal Investigator William F. Fearon, MD, commented in the company's announcement, “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.” Dr. Fearon is with the Stanford University School of Medicine and Stanford Cardiovascular Institute at Stanford University in Stanford, California.
Dr. Price, who is Director of Cardiac Catheterization Laboratory at Scripps Clinic in La Jolla, California, stated, “The difference found between FFR measurements with a pressure wire and microcatheter tended to be influenced by RVD and lesion length; however, from a practical perspective, the clinician can just look at the microcatheter FFR itself." He continued, “This study confirms and expands upon previous findings in a much more robust manner. It is encouraging to see these data further validate the diagnostic capabilities and technical merit of microcatheter FFR technology.”