934-24 Do Angiographic Measurements of Stenosis Severity Correlate with Doppler Flow Reserve? Effect of Balloon Angioplasty

The aim of the study is the correlation between angiographic and flow velocity measurements correlated before and after PTCA. In 72 patients undergoing PTCA for a single lesion in a major coronary artery, a Doppler guidewire was used to measure distal flow velocity before and 15 minutes after angiographically successful PTCA. Both measurements were repeated after intracoronary adenosine. A computer-assisted automated edge detection (CAAS II) was used to assess the angiographic minimal luminal diameter (MLD) and percentage diameter stenosis (DS). Minimal luminal cross-sectional area (MLCSA) and percent cross-sectional area stenosis (CSA-St) were assessed with videodensitometry. Results after PTCA, MLD increased from 1.09±0.29mm to 1.83±0.33mm, DS decreased from 61±4% to 36±2% (both p<0.0001), while CSA-St decreased from 79±12% to 48±16% (p<0.0001). Distal coronary flow reserve (CFR) increased from 1.58±0.64 before PTCA to 2.58±0.94 after PTCA, p<0.0001. Distal CFR was significantly correlated with MLD (see figure), MLCSA, DS and CSA-St before PTCA. After PTCA no correlation was observed between distal CFR and both geometric and densitometric indices of stenosis severity. In conclusion, the poor correlation after PTCA between quantitative angiographic measurements and distal coronary flow reserve may indicate acute or chronic disturbance of flow regulation and/or may reflect the limitations of angiography in the assessment of lumen geometry after PTCA.