Starting in January 2019 through December 2019 a recommendation to obtain a repeat LEVDUS after an I/N study was appended to the preliminary and final reports of all I/N LEVDUS of patients who did not otherwise have an indication for anticoagulation (Group 2). Patients were identified on an ongoing basis through the study period and entered into an Excel database. Group 2 patients were compared to a previously reported historic control cohort of patients identified January 2017 to December 2017 (Group 1). We compared Groups 1 and 2 with respect to the frequency of repeat studies performed within 4 weeks following an I/N LEVDUS and DVT rates of the follow-up LEVDUS following an I/N LEVDUS.
There were 187 Group 1 and 229 Group 2 I/N LEVDUS with 28% of Group 1 and 40.2% of Group 2 studies with follow-up duplex US examination; P<.01. Previously unidentified lower extremity thrombi were discovered in 21% of Group 2 follow-up examinations and the rate of new thrombi detected was not different in Group 2 vs. Group 1, the historic controls, (DVT: 14.3% vs 18.5%, P=.25 and SVT: 6.3% vs 3.3%, P=.15). There was a definitive answer of either positive for DVT/SVT or negative and complete in 50% of Group 2 patients with follow-up examinations.
A recommendation to obtain a follow-up examination appended to preliminary and final reports of I/N LEVDUS is associated with an increased rate of follow-up examinations which revealed many previously undetected DVTs and SVTs or allowed for definitive exclusion of DVT.