Validation of Minimal Luminal Area Measured by Intravascular Ultrasound for Assessment of Functionally Significant Coronary Stenosis: Comparison With Myocardial Perfusion Imaging

Abstract

This study sought to evaluate the ability of minimal luminal area (MLA) measured by intravascular ultrasound (IVUS) to assess the functional significance of coronary artery disease. The use of IVUS to determine the functional significance of coronary artery lesions remains a matter for debate. From our prospective IVUS imaging database, between July 2009 and April 2010, 170 coronary lesions in 150 patients who underwent stress myocardial single-photon emission computed tomography (SPECT) performed within 1 month of IVUS evaluation were identified and analyzed. MLA and other parameters were measured by IVUS and compared with the results of myocardial SPECT. Overall, 45 lesions had positive SPECT, and 125 lesions had negative SPECT. The MLA of lesions with positive SPECT was smaller than the MLA of those with negative SPECT (1.7 ± 0.5 mm² vs. 2.3 ± 1.1 mm², p < 0.001). By logistic regression analysis, MLA (odds ratio: 3.1 by decrease of 1 mm², 95% confidence interval [CI]: 1.75 to 5.5, p < 0.01) was an independent predictor of the positive SPECT. Using receiver-operator characteristic curve analysis, the best cutoff value of MLA was ≤ 2.1 mm² with an 86.7% sensitivity, a 50.4% specificity, a 38.6% positive predictive value, and a 91.3% negative predictive value versus lesions with a positive SPECT (area under the curve: 0.690, 95% CI: 0.615 to 0.759, p < 0.01). The best cutoff value of MLA measured by IVUS to predict myocardial ischemia was 2.1 mm². The IVUS-measured MLA appeared to play a limited role in detecting functionally significant lesions assessed by myocardial SPECT.