A randomised controlled trial to compare two coronary pressure wires using simultaneous measurements in human coronary arteries: the COMET trial.

We aimed to examine the relative performance of the new COMET wire from Boston Scientific (BS), and the established technology from St. Jude/Abbott Vascular (SJ). We compared simultaneous readings from pairs of wires. Patients were randomised to one of three groups: BS/BS, SJ/SJ, or SJ/BS. The last group was sub-randomised to specify the type of wire that would be passed first. After pressure equalisation at the guide catheter, we recorded paired observations in sequence: (a) distal to proximal pressure ratio at baseline, (b) FFR at maximum hyperaemia, and (c) pressure on withdrawal into the guide catheter to quantify "drift". We randomised 106 patients, yielding 288 sets of paired recordings (BS/BS=90; SJ/SJ=90; SJ/BS=108). Drift was recorded from 208 vessels (BS=105; SJ=103). All wires were successfully advanced to their desired positions in the coronary vasculature. The mean (±SD) differences for the randomised pairs were similar: BS/BS=0.0016 (0.023); SJ/SJ=0.002 (0.03); SJ/BS=0.0013 (0.028). The primary outcome tested the hypothesis that the absolute magnitude of the difference (irrespective of sign) observed in the SJ/BS pairing would be similar to that in the SJ/SJ group. The median (IQR) values were SJ/BS=0.015 (0.01-0.03); SJ/SJ=0.01 (0.00-0.03); p=0.61. The drift, expressed as the median (IQR) difference in Pd/Pa from 1.0 (irrespective of sign), was similar: BS=0.02 (0.01-0.05); SJ=0.02 (0.01-0.04); p=0.14. We found no significant difference between these wires in terms of safety and performance.