Objective      To determine the value of intravascular ultrasound (IVUS) in optimization of diagnosis and treatment in coronary intermediate stenosis

by comparing its results with those by quantitative coronary angiography (QCA).       

Methods      Clinical data of 19 patients who received QCA and identified with stenosis between 40% to 70% in our department from October 2010 to December 2011 were enrolled in this study. QCA and IVUS was used to analyze the parameters of atherosclerotic plaques in the patients with intermediate stenosis

such as

minimal lumen diameter (MLD)

area stenosis (%AS) and diameter stenosis (%DS). The types

characteristics and compositions of coronary plaques were observed with the IVUS and iMAP-IVUS. Stent implantation was performed on the patient with %AS ≥70% by IVUS.       Results      QCA and IVUS showed that the MLD

%DS and %AS were 1.75±0.39

vs

2.07±0.40 mm

(35.04±13.60)%

vs

(46.37±8.02)%

  and (52.91±15.96)%

vs

(62.61±11.54)%

respectively (

P

<

0.05). Myocardial bridging was identified in 7 patients (36.8%) by QCA

and in 10 patients (52.6%) by IVUS. IVUS showed there were 63.2% soft plaques

15.8% fibrotic plaques

10.5% calcified plaques

and 10.5% mixed plaques; there were 84.2% eccentric plaques and 15.8% concentric plaques; and there were 57.9% positive remodeling

26.3% negative remodeling

and 15.8% non-remodeling. iMAP-IVUS showed there were 14 cases  of thin-cap fibroatheroma (TCFA). We presumed that positive remodeling might be associated with instability of plaques.        Conclusion      IVUS improves the accuracy of intermediate stenosis diagnosis

and easy to find out vulnerable plaque. So it is helpful to screen the patients with high risk so as to carry out early intervention and treatment.