T. Yoo1, R. Aggarwal1, S. Brathwaite1, B. Satiani1, M. J. Haurani1 1Ohio State University,Vascular/Surgery,Columbus, OH, USA
Introduction: Duplex Ultrasonography (DUS) is the gold standard for diagnosis of deep vein thrombosis (DVT) due to its high specificity/sensitivity, safety, and portability. However, unnecessary testing may represent an inefficiency that pervades healthcare. Here we hypothesize that the majority of four extremity DUS, often ordered for fever of unknown origin (FUO), is unnecessary. Furthermore, by analyzing patient and clinical factors of patients with an acute DVT on four extremity DUS, we aim to identify a subset of high-risk patients that may benefit from four extremity testing.
Methods: We retrospectively reviewed all venous DUS performed in our Intersocietal Accredited Commission Vascular Laboratory from January 1st, 2009, to December 31st, 2016. Patients with DUS of all 4 limbs were included. DVT risks factors, and indication for DUS was recorded. Primary outcome was finding of acute DVT.
Results: 188 patients met criteria of which 31 patients (16.5%) had acute DVT (11 upper extremity, 16 lower extremity, 4 upper and lower extremity). Factors associated with positive DUS were recent surgery (OR =2.50, p<0.02), hospitalization≥7 days (OR=3.85, p<0.01), immobility≥7 days (OR=3.67, p<0.01), presence of central venous catheter (CVC) (OR=3.40, p<0.01), and active malignancy (OR=2.52, p<0.02). FUO was the main indication for requesting four extremity DUS (53.7%). Patients who underwent four extremity DUS for FUO had significantly lower likelihood of DVT (OR=0.41, p<0.02), of which DVT was rarely the proximate cause (<1% of all cases), as follow-up culture results and clinical course most often revealed other sources of fever. Patients with known acute PE had the most significant likelihood of DVT (OR=22.6, p<0.01). Prophylaxis was found to be protective for acute DVT (OR=0.33, p<0.01). Only patients with an upper extremity CVC had an upper extremity DVT, which was usually line associated (93%).
Conclusion: Four limb DUS for FUO is inefficient given that DVT was rarely the proximate cause of fever. Upper extremity acute DVT was only found in patients with an ipsilateral CVC. When upper extremity DVT iss present, the extremity associated with the CVC should be imaged, while the contralateral extremity does not need a full-limb DUS. Our results indicate that a restrictive strategy can reduce DUS testing inefficiency and healthcare cost without compromising patient safety.