Pressure wire versus microcatheter for FFR measurement: a head-to-head comparison.

ABSTRACT

AIMS: Recently developed microcatheters can be used instead of a pressure wire for fractional flow reserve (FFR) measurement. We sought to assess the haemodynamic and clinical impact of using a larger profile device to measure FFR. METHODS AND RESULTS: Our prospective registry included 77 consecutive patients who underwent invasive FFR measurement of intermediate coronary stenoses between June 2015 and July 2016. FFR values were obtained first using a pressure wire only (FFRw), second using a Navvus microcatheter (FFRMC), and finally using the wire with the microcatheter still in the stenosis (FFRw-MC) during intravenous adenosine infusion. Eighty-eight stenoses were suitable for a thorough head-to-head comparison. Mean FFRw (0.83±0.08) was significantly higher than mean FFRMC (0.80±0.10) and FFRw-MC (0.80±0.10). Mean FFRMC and FFRw-MC did not differ significantly. Bland-Altman analysis showed a bias of -0.03±0.05 for lower FFRMC values compared to FFRw values. Using a threshold of 0.80 for FFR, the indication for revascularisation would have differed when based on FFRMC versus FFRw in 20/88 (23%) of the lesions and 18/77 (23%) of the patients. CONCLUSIONS: FFR measured using a microcatheter overestimates stenosis severity, leading to erroneous indication for revascularisation in a sizeable proportion of cases.