IN-VITRO EVALUATION OF THE INTRAVASAL DOP PLER GUIDE-WIRE - DETERMINATION OF HEMODYNAMIC-EFFECTS OF STENOSES IN A FLOW MODEL

Purpose: In a pulsatile hydraulic model, haemodynamic changes caused b y stenoses were assessed using an intravascular Doppler guide wire. Ma terial and methods: In defined stenoses (25, 50, 75 and 87.5% diameter ratio), and with and without collateral flow, a 0.018 inch (0.46 mm) 12 MHz Doppler guide wire was assessed. Flow velocity measurements wer e taken 20 mm proximal, in, and 20 mm distal to the stenoses. Average peak velocity (APV) and ratios of pre-/poststenotic velocities and pre -/intrastenotic velocities of APV were compared with the grade of sten osis. The degree of the stenosis calculated by the ratio of the cross- sectional area, using the pre- and intrastenotic APV, was correlated w ith the actual stenosis. Results: The intrastenotic APV increased sign ificantly (APV proximal to the stenosis 15.15 +/- 4.5 cm/s, intrasteno tic APV 134.8 +/- 130.9, p < 0.01, Wilcoxon-Mann-Whitney test). The di fference between APV pre- and poststenotic was not significant (p > 0. 5). Concerning the grade of stenosis the ratio APV pre-lintrastenotic and the consecutively calculated cross-sectional area stenoses was the best predictor (correlation with the known cross-sectional area steno sis r=0.94 Pearson). Conclusion: Using the Doppler guide wire, APV mea surements pre- and intrastenotic enable a reliable quantification of t he grade of stenosis. The stenosis calculated via the cross-sectional area correlates significantly with the actual stenosis.