Can an intracoronary doppler wire accurately measure changes in coronary blood flow velocity?

The purpose of this study was to compare a newly developed Doppler guide wire in the measurement of coronary blood flow velocity (CBFV) and coronary flow reserve (CFR) when compared to a previously extensively validated Doppler catheter. Sequential measurements of Doppler signals from the Doppler catheter and wire were obtained in response to graded doses of intracoronary adenosine in the left circumflex of 10 anesthetized dogs. The Doppler catheter signal was recorded on a standard physiologic chart recorder; that from the Doppler wire was recorded both on the chart recorder and the commercially available spectral analysis recording system. High correlations were obtained between the change in coronary velocity and CFR which were independent of the recording system used. Peak flow reserve in response to maximum intracoronary adenosine (24 micrograms bolus) ranged from 3.7-5.6 x basal. These results are similar to those obtained in normal humans. In spite of major differences between engineering specifications of the Doppler wire and Doppler catheter, under optimal conditions these two techniques yield similar results. The Doppler wire may facilitate measurements of CFR during diagnostic angiography in small or diffusely diseased vessels.