Comparison of 2-point and 3-point point-of-care ultrasound techniques for deep vein thrombosis at the emergency department: A meta-analysis

Background: To our knowledge, so far, no studies have comprehensively examined the performance of 2-point and 3-point pointof- care compression ultrasound (POCUS) in the diagnosis of lower extremity deep vein thrombosis (DVT). The aim of this metaanalysis was to compare the performance of 2-point and 3-point POCUS techniques for the diagnosis of DVT and evaluate the falsenegative rate of each POCUS method. Methods: A computerized search of the PubMed, EMBASE, and Cochrane library databases was performed to identify relevant original articles. Bivariate modeling and hierarchical summary receiver operating characteristic modeling were performed to compare the diagnostic performance of 2-point and 3-point POCUS. The pooled proportions of the false-negative rate for each POCUS method were assessed using a DerSimonian-Laird random-effects model. Meta-regression analyses were performed according to the patient and study characteristics. Results: Seventeen studies from 16 original articles were included (2-point, 1337 patients in 9 studies; 3-point, 1035 patients in 8 studies). Overall, 2-point POCUS had similar pooled sensitivity [0.91; 95% confidence interval (95% CI), 0.68-0.98; P=.86) and specificity (0.98; 95% CI, 0.96-0.99; P=.60) as 3-point POCUS (sensitivity, 0.90; 95% CI, 0.83-0.95 and specificity, 0.95; 95% CI, 0.83-0.99). The false-negative rates of 2-point (4.0%) and 3-point POCUS (4.1%) were almost similar. Meta-regression analysis showed that high sensitivity and specificity tended to be associated with an initial POCUS performer (including attending emergency physician >only resident) and separate POCUS training for DVT (trained >not reported), respectively. Conclusion: Both 2-point and 3-point POCUS techniques showed excellent performance for the diagnosis of DVT. We recommend that POCUS-trained attending emergency physicians perform the initial 2-point POCUS to effectively and accurately diagnose DVT.