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Validation of Subclavian Duplex Velocity Criteria to Grade the Degree of Stenosis in Occlusive Subclavian Artery Disease
ALBEIR MOUSA,MD.,FACS.,RPVI.,MPH.,MBA1, Mike Broce, BA2, Ramez N. Morkous1, Michael Yacoub, MD1, Aravinda Nanjundappa, MD1, Andrew Sticco, MD1, Zackary AbuRahma, DO1, Shadi AbuHaliamh, MD1, Ali AbuRahma, MD1.
1West Virginia Univeristy, Charleston, WV, USA, 2Charleston Area Medical Center Health Education and Research Institute, Charleston, WV, USA.
Objective: Validation of subclavian duplex ultrasound velocity criteria (SDUS VC) to grade the severity of subclavian artery stenosis (SAS) has not been established nor published. There is no consensus among practitioners for what SDUS VC should be considered when evaluating SAS.
The objective of the present study was to validate SDUS measurements using subclavian angiography (SA) derived measurements. Secondary objectives included measuring the correlation between SDUS values and SA measurements, and determining the optimal cut-off value for predicting significant stenosis (>70%).
Methods: A retrospective review of all patients with suspected SAS and a convenience sample of carotid artery patients who underwent SDUS and SA from May 1999 to July 2013. Vessel diameters were measured by SA, and corresponding SDUS velocities recorded. Percent stenosis by SA was calculated using the North American Symptomatic Carotid Endarterectomy Trial method for detecting stenosis in a sufficiently large cohort. A receiver operating characteristic (ROC) curve was generated for SDUS VC to predict >70% stenosis. Velocity cut-off points were determined with equal weighting of sensitivity and specificity.
Results: We examined 268 arteries for 177 patients. Majority were females (52.5%) with a mean age of 66.7 ± 11.1 years. Twenty-three subclavian arteries had vertebral retro-grade flow, with treated stenosis and excluded from further analysis. For the remaining 245 arteries, the average peak systolic velocity (PSV) was 212.6 + 110.7 centimeters per second (cm/s), with a range of 45-626 cm/s. Average stenosis was 25.8 + 28.2%, with a range of 0-100%. More arteries were on the left side (53%). Following ROC analysis a cut-off value of >240 cm/s best predicted stenosis >70%. Area under the curve (AUC) was 0.91 with 95% confidence intervals of 0.91 to 0.97. The sensitivity and specificity for predicting >70% stenosis was 90.9 and 82.5%, respectively.
Conclusion: SDUS VC appeared to be effective in predicting 70% stenosis in subclavian arteries with good sensitivity and specificity. We propose new PSV criteria to be used for predicting subclavian artery stenosis. However, it is possible the current proposed cut-off point may need to be adjusted for other populations.
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