Coronary blood flow shows phasic and diastolic dominant flow pattern in normal coronary artery, which can be changed in coronary artery stenosis. We measured and analysed coronary blood flow velocity by Doppler-tipped guidewire to clarify the change of flow pattern in the proximal and distal segments of coronary narrowings.

Coronary flow velocity were measured by 0.018 or 0.014 inch Doppler-tipped guidewire in 14 paients, 17 sites(LCS 11, RCA 6) in the proximal and distal segment of coronary narrowings, during coronary angiography or coronary angioplasty after bolus intracoronary infusion of 20µg nitroglycerine. Coronary flow reserve also measured after adenosine intracoronary infusion(LCA 12gµg, RCA 6µg). Perent stenosis of coronary artery was measured by digital cailper in 2 different projections and averaged.

1) The was no significant correlation between percent stenosis and proximal distal velocity ratio(P/D) ration(r=0.56. P>0.05).

2) Average peak velocity(APV, cm/sec) and diastolic artery, respectively(p<0.01) Distal APV was significantly lower than proximal APV(p<0.01) but DSVR showed no significant difference(P>0.01).

3) Coronary flow reserve(CFR) was significantly lower in significant coronary stenotic patients compared to insignificant stenotic patients(1.8 vs 3.6, P<0.01).

Coronary flow velocity measurement by Doppler dipped guidewire gave us physiologic information. We think it could be used as an important tool to assess the significance of the intermediate coronary narrowings and the effect of conorary angioplasty.