Hutchisson, Marge

Introduction: Accreditation of vascular laboratories has been shown to lead to overall improvements in quality patient care. However, there are still factors that needlessly delay the granting of full accreditation. We performed a retrospective analysis looking at factors associated with delays in accreditation in extracranial carotid artery ultrasound examinations by the Intersocietal Accreditation Commission - Vascular Testing (IAC-VT) division. Materials and Methods: We accessed an active database from the IAC-VT division between 2014 and 2020 and extracted data linked to vascular laboratory accreditation in extracranial carotid ultrasound studies. We used the ‘Delay” versus the “Grant” status as outcome and looked at the association with 18 metrics that are part of the application evaluation. We further used a modified Delphi method to determine the relative role played by either the technologist/sonographer or the interpreting physician for each metric. Statistical significance was evaluated by Chi-square. Results: A “Delay” status was assigned in 1638 (58.6%) out of 2794. Ten factors were noted to be significant univariate predictors of a “Delay” status. The three major factors were solely associated with the interpreting physician while adherence to technical factors showed mostly shared responsibility. Conclusion: This retrospective study indicated that the accreditation process is strongly dependent on interpreting physician performance. Targeted interventions may help decrease time and effort associated with the costs of the accreditation process.

Diagnostic criteria to classify severity of internal carotid artery (ICA) stenosis vary across vascular laboratories. Consensus-based criteria, proposed by the Society of Radiologists in Ultrasound in 2003 (SRUCC), have been broadly implemented but have not been adequately validated. We conducted a multicentered, retrospective correlative imaging study of duplex ultrasound versus catheter angiography for evaluation of severity of ICA stenosis. Velocity data were abstracted from bilateral duplex studies performed between 1/1/2009 and 12/31/2015 and studies were interpreted using SRUCC. Percentage ICA stenosis was determined using North American Symptomatic Carotid Endarterectomy Trial (NASCET) methodology. Receiver operating characteristic analysis evaluated the performance of SRUCC parameters compared with angiography. Of 448 ICA sides (from 224 patients), 299 ICA sides (from 167 patients) were included. Agreement between duplex ultrasound and angiography was moderate (κ = 0.42), with overestimation of degree of stenosis for both moderate (50–69%) and severe (⩾ 70%) ICA lesions. The primary SRUCC parameter for ⩾ 50% ICA stenosis of peak-systolic velocity (PSV) of ⩾ 125 cm/sec did not meet prespecified thresholds for adequate sensitivity, specificity, and accuracy (sensitivity 97.8%, specificity 64.2%, accuracy 74.5%). Test performance was improved by raising the PSV threshold to ⩾ 180 cm/sec (sensitivity 93.3%, specificity 81.6%, accuracy 85.2%) or by adding the additional parameter of ICA/common carotid artery (CCA) PSV ratio ⩾ 2.0 (sensitivity 94.3%, specificity 84.3%, accuracy 87.4%). For ⩾ 70% ICA stenosis, analysis was limited by a low number of cases with angiographically severe disease. Interpretation of carotid duplex examinations using SRUCC resulted in significant overestimation of severity of ICA stenosis when compared with angiography; raising the PSV threshold for ⩾ 50% ICA stenosis to ⩾ 180 cm/sec as a single parameter or requiring the ICA/CCA PSV ratio ⩾ 2.0 in addition to PSV of ⩾ 125 cm/sec for laboratories using the SRUCC is recommended to improve the accuracy of carotid duplex examinations.