Evaluation of severe subclavian artery stenosis by color Doppler flow imaging

This study evaluates the diagnostic value of the hemodynamic parameters of color Doppler flow imaging (CDFI) for severe (70 to 99%) subclavian artery stenosis (SAS) using digital subtraction angiography (DSA) as the reference standard. Two-hundred fifty-two patients with suspected SAS were recruited into the study and examined from June 2005 to December 2009. The degree of stenosis was classified as moderate (50 to 69%) or severe (70 to 99%) stenosis. By using CDFI, the residual diameter (Dr), peak systolic velocity (PSV1) and end diastolic velocity (EDV) at the stenotic vessel segments, as well as the original diameter (Do) and PSV2 of the relative normal segments distal to the stenosis (the segment distal to the poststenotic dilation) were recorded. The diameter stenosis rate (1-Dr/Do) and PSV ratio (PSV1/PSV2) were calculated. Using DSA as the reference standard, the diagnostic values and optimal cutoff values for each parameter for the evaluation of severe (70%-99%) were determined using receiving operating characteristic curve analysis. Among the 252 patients, 109 patients were diagnosed as having severe (70 to 99%) SAS and 143 patients had moderate (50 to 69%) SAS. The optimal cutoff values for PSV1, EDV and the PSV1/PSV2 ratio for evaluating severe (70 to 99%) SAS were PSV1 ≥343 cm/s, EDV ≥60 cm/s and PSV1/PSV2 ≥4.0, respectively. The accuracy for diagnosing SAS with PSV1 (86.1%) was higher than that of EDV (85.7%), PSV1/PSV2 (84.9%) and 1-Dr/Do (80.2%). In addition, when PSV1 was used in combination with EDV and 1-Dr/Do, the accuracy for diagnosing SAS increased from 86.1% to 87.3%. When PSV1 was used in combination with EDV and PSV1/PSV2, the accuracy for diagnosing SAS reached 95.8%. In conclusion, the CDFI hemodynamic parameters of PSV1, EDV and PSV1/PSV2 show good consistency with DSA for diagnosing severe (70 to 99%) SAS, and a combination of these three parameters can ensure even greater accuracy for diagnosing SAS.