Predictors of a technically limited renal artery duplex study: A retrospective analysis

Objective. - A renal artery duplex study is the screening study to evaluate for renal artery stenosis. A nondiagnostic study from a renal artery duplex study can be frustrating and labor intensive, with diminished revenue for the vascular laboratory. The purpose of this study is to evaluate patient and environmental factors in predicting a limited study. Methods. - A retrospective chart review of patients who underwent a renal artery duplex study in an Intersocietal Commission for the Accreditation of Vascular Laboratories- accredited vascular laboratory from July 2005 through June 2008 was performed. Patient age, body mass index, technologist experience, and the patient location where imaging was performed (inpatient versus outpatient) were collected and evaluated. A univariate and multivariate analyses were performed by use of the continuous and proportional measures. A p value of less than 0.05 was considered significant. Results. - A total of 390 patients had a renal artery duplex performed during this time period. Of the 390 duplex studies that were performed, 66% (258/390) were considered complete studies. The average age of patients with complete studies was 62 ± 16 versus incomplete 62 ± 15 (p = NS). In the univariate analysis, complete studies were more likely to be performed by experienced technologists (p = 0.04), in an outpatient setting (p < 0.001), in patients with a lower body mass index (p = 0.01). In the multivariate analysis, only body mass index (p = 0.01) and outpatient status (p = 0.002) were found to be significant predictors of a complete study. Conclusions. - One-third of the renal artery duplex studies were limited in our retrospective review. Experience of the ultrasound technologist, lower body mass index of the patient, and the outpatient setting for the study appear to play a crucial role in obtaining a complete study. A prospective analysis of the factors will be necessary to confirm these findings.