Evaluation of coronary flow feserve by intracoronary Doppler flowire

Objective To evaluate the intracoronary Doppler flowire in coronary arteries with or without stenosis. Methods 55 patients with coronary angiography were studied by Cardiometrics FloMap Ⅱultrasound instrument and 0.014 inch flowire. The patients were divided into four groups. Group A consisted of 7 patients without underlying diseases of coronary microvascular lesions and with normal angiography. Group B consisted of 20 patients with underlying diseases of coronary microvascular lesions including hypertension 16, hypertension combined with diabetes 2, and cardiomyopathy 2. Group C consisted of 12 patients with moderate stenosis (30%~70% diameter narrowing in angiography). Group D consisted of 16 patients with severe stenosis (70% diameter narrowing in angiography). The measurements included distal baseline average peak velocity (APV), hyperemic APV and flow reserve (CFR). Results The baseline APV in group B was higher than group A [(19.05±6.46) vs (15.39±6.29), P0.05], so CFR in group B was significantly lower than group A [(2.48±0.69) vs (3.19±0.65), P0.0005]. To assess the difference of APV between patients with normal and abnormal CFR in group B, CFR2.0 was determined as normal CFR criteria according to group A. CFR was normal in 37 arteries (77%), and 11 arteries (23%) was abnormal. Among the 11 abnormal CFR arteries, 7 arteries (63.64%) with left ventricular hypertrophy. Compared with group A, CFR in distal arteries had significantly decreased in group C [(2.02±0.48) vs (3.19±0.65), P0.001], CFR had further deterioration in group D [(1.50±1.01) vs (3.19±0.65), P0.005]. Significantly lower hyperemic APV was also observed in group D [(21.69±16.28) vs (46.32±14.08), P0.001]. Conclusions Although the coronary angiography was normal in patients with underlying diseases of coronary microvascular lesions, 23% arteries had abnormal CFR. Compared with normal coronary control, CFR was further decreased with increassing severity of stenosed coronary arteries.