The Additive Diagnostic Role of Coronary Flow Reserve in Noninvasive Evaluation of Coronary Stenosis on Left Descending Artery Previously Detected by Multislice Computed Tomography

Purpose: Multislice computed coronary angiography (MSCT) provides valuable morphological information about coronary artery disease, but precise quantification of coronary stenosis remains difficult. Transthoracic color Doppler echocardiography (TDE) gives a new insight into the functional significance of coronary luminal narrowing. We have tried to assess the additive value of coronary flow reserve (CFR) determined by TDE over MSCT in prediction of a significant stenosis on the left anterior descending artery (LAD) using the invasive coronary angiography (ICA) as a reference method. Methods: This prospective study included 63 patients in stable cardiac status with previously detected atherosclerotic lesions on LAD by MSCT. CFR assessment by TDE with adenosine infusion was obtained to all patients (feasibility was 96.92%). CFR was determined as ratio between the peak diastolic flow velocity during adenosine infusion and at basal condition, a cutoff value indicating significant stenosis was <2. ICA was preformed to all patients 2448hours after CFR. Results: MSCT had sensitivity of 86.36%, specificity 53.66%, positive predictive value 50.00%, negative predictive value 88.00%, and diagnostic accuracy of 65.07% in detection of significant LAD stenosis. CFR had sensitivity 81.81%, specificity 97.06%, positive predictive value 94.74%, negative predictive value 89.19%, and diagnostic accuracy of 91.07%. When the results of both methods were agreed diagnostic accuracy was improved to 92.72%. Conclusion: Additional assessment of CFR by TDE increase diagnostic accuracy of MSCT angiography in detection of significant coronary artery lesions.