P280Transthoracic echocardiography for detection of coronary artery stenoses by use of coronary poststenotic diastolic to systolic velocity ratio in the left anterior descending and circumflex arteries


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Abstract

Purpose: Recent reports have indicated that use of the diastolic to systolic flow velocity ratio (DSVR) measured by transthoracic Doppler echocardiography (TTE) in the distal left anterior descending coronary artery (LAD) is a simple noninvasive method for detecting coronary stenoses located more proximally in the LAD, with significant reduction of the diastolic relative to the systolic flow component when measured poststenotically. However, various cut-off values for significant stenosis have been proposed, with peak DSVR (pDSVR) < 1.6 – 1.8 representing significant stenosis in different studies. To the best of our knowledge, there are no data on TTE DSVR measurements of the circumflex coronary artery (Cx). The purpose of this study was to evaluate by TTE the potential of DSVR measured in distal-to-mid LAD (dmLAD) and marginal branches of Cx (CxMb) for detecting coronary stenoses in the left main (LM), LAD and Cx arteries, compared with quantitative coronary angiography (QCA).Methods: A total of 108 patients scheduled for coronary angiography because of chest pain or acute coronary syndrome were studied. When the relevant coronary segment was identified with antegrade flow, the pDSVR was measured in dmLAD and CxMb. Peak DSVR results were compared with results from QCA, with stenosis severity in the LM/LAD and LM/Cx divided into 2 groups: (1) diameter stenosis 0-49%; (2) diameter stenosis 50-100%. Each main coronary artery could have more than one stenosis, with the most tight stenosis defining the degree of stenosis.Results: Peak DSVR was successfully measured in dmLAD and CxMb in 83% and 31% of patients, respectively. Among coronary arteries with DSVR measurements, QCA identified 34 group 2 stenoses in LAD and 5 group 2 stenoses in Cx. Peak DSVR was significantly different between the groups, with pDSVR 1.90 ± 0.31 in group 1 and 1.50 ± 0.16 in group 2 (p < 0.001). ROC analysis showed that a pDSVR cut-off value of 1.68 had specificity of 90 % and sensitivity of 84 % for detection of group 2 stenoses. Excluding the Cx, the same pDSVR cut-off value had specificity of 91 % and sensitivity of 86 % for detection of group 2 stenoses in LAD.Conclusions: DSVR measurements in dmLAD were feasible in the majority of patients and in CxMb in 1/3 of patients. The ROC analysis showed that a pDSVR cut-off value of 1.68 had high precision for identifying significant stenoses in LAD and Cx, defined as diameter stenosis 50-100%. (ClinicalTrials.gov number NTC00281346.)

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