Validation of minimal luminal area measured by intravascular ultrasound for assessment of functionally significant coronary stenosis comparison with myocardial perfusion imaging.

OBJECTIVES: 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.
BACKGROUND: The use of IVUS to determine the functional significance of coronary artery lesions remains a matter for debate.
METHODS: 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.
RESULTS: 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).
CONCLUSIONS: 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.