Assessment of coronary fractional flow reserve using a monorail pressure catheter: the first-in-human ACCESS-NZ trial

Aims: FFR measurements have been limited by the handling characteristics of pressure wire (PW) systems, and by signal drift. This first-in-human study evaluated the safety and efficacy of a new monorail catheter (Navvus) to assess coronary FFR, compared to a PW system. Methods and results: Resting measurements were acquired with both systems. After initiating IV adenosine, FFR was measured with the PW alone, simultaneously using both systems, and again with PW alone. Any zero offset of PW or Navvus was then recorded. Navvus measured FFR in all patients in whom a PW recording was obtained (50 of 58 patients); there were no complications related to Navvus. Navvus FFR correlated well with PW FFR (r=0.87, slope 1.0, intercept -0.02). Within PW measurement accuracy, in no cases did Navvus FFR classify lesion significance differently from PW FFR. PW signal drift was significantly greater than Navvus (0.06 +/- 0.12 vs. 0.02 +/- 0.02, p=0.014). Conclusions: Navvus and PW FFR correlated well. Navvus had less sensor drift. This new catheter-based system offers an alternative method for measuring FFR, with some potential advantages over PW.