PC164. Evaluation of Incomplete Lower Extremity Duplex Venous Ultrasound Examinations

Abstract

Deep venous thrombosis (DVT) positive lower extremity venous duplex ultrasound (LEVDUS) examination is an indication for anticoagulation. Incomplete examinations that fail to examine all LE veins in patients not otherwise indicated for anticoagulation may be followed by a repeat examination to exclude missed/progressing DVT. This study examined the frequency of follow-up LEVDUS following incomplete LEVDUS and compared the incidence of positive DVT between initial complete LEVDUS and follow-up LEVDUS after an initial incomplete examination to determine if improving rates of follow-up LEVDUS following an incomplete examination is a reasonable target for quality improvement. From December 2016 to December 2017, incomplete LEVDUS were prospectively identified in patients who did not have an identified indication for anticoagulation. We determined the frequency/demographics of repeat studies performed within 2 weeks after incomplete LEVDUS and DVT rates of initial and repeat LEVDUS. There were 4,828 LEVDUS studies (ankle to groin) performed; 223 (4.8%) were incomplete and did not otherwise identify DVT in the ipsilateral or contralateral leg. Of incomplete studies, 80.3% were ordered in-hospital, 12.1% from outpatient clinics, 7.6% from the ED, with 9.9% ordered by primary care providers, 33.6% by specialists, 29.1% by trauma surgeons and 27.4% by emergency department providers. Initial indications for incomplete studies were high-risk screening in 52.5%, and LE signs/symptoms in 47.5%. In addition, 63.2% of incomplete studies resulted from bandages, wounds, braces, casts or fixation devices, 13.5% from edema, 5.8 % from body habitus and 12.1% from patient study intolerance. Deep veins inadequately evaluated on initial LEVDUS included femoral (36.8%), popliteal (40%) and axial calf veins (85.7%). Sixty-one patients (27.3%) with incomplete LEVDUS had repeat examinations. 11.5% had thrombi detected with six in deep and two in superficial veins. Only 18 of 105 symptomatic patients with an incomplete study had a repeat study with 71% of follow-up studies for screening patients (P < .001). DVT diagnosis rates were similar between initial complete LEVDUSs (8.7%) and repeat LEVDUSs performed after an initial incomplete examination (8.2%; P = .65). Almost one-half of incomplete LEVDUSs are ordered in symptomatic patients. However, the large majority of patients with incomplete LEVDUS, even those with symptoms, do not have a follow-up examination but patients with repeat studies have a DVT diagnosis rate equivalent to patients with an initial complete examination, suggesting the need for quality assurance programs to ensure repeat studies are performed after incomplete LEVDUS, particularly in symptomatic patients.