Deep vein thrombosis outpatient pathway and ultrasound sensitivity Dr Loay Abdelnour Pinderfields General Hospital

Introduction Incidence of DVT: 100/100,000 in USA, and 104- 183/100,000 in European population NICE guidelines recommend HISTORY & CLINICAL EXAM =Wells Score

NICE Algorithm

Aims Pooled sensitivity for various USS techniques is 94.2% What is USS compression sensitivity in our institution? Does this sensitivity vary across patients’ subsets?

Methods Retrospective analysis of medical records 12 Months period

Table 1: Baseline characteristics of study population The table shows the baseline characteristics of 568 subjects referred for a first USS. IVDU, intravenous drug user; VTE, venous thromboembolism Table 1: Baseline characteristics of study population   Characteristic   N = 568 Missing Data (%) Age, mean (years) 61.16 0.00 Female gender (%) 54.40 IVDU (%) 07.57 0.30 Active cancer (%) 08.80 Previous VTE (%) 19.54 0.10 Recent surgery (%) 10.21 Bed-bound (%) 07.74 0.50 Recent long-haul flight (%) 02.81 Paralysis (%) 0.700 Positive D Dimers test (%) 58.09 25.88 Wells score of 2 points or more (%) 63.02 02.64 Wells score (mean) 02.01

Results: Study Flowchart

Results: All patients Sensitivity = 132/ (132 + 14) = 90.41%

Results: IVDU Flowchart

Results: IVDU Subset Sensitivity = 31 / (31 + 6) = 83.7%

Table 2: Characteristics of patients with positive second USS D-Dimers Wells score 1 Positive 3 2 4 Not done 5 6 Negative 7 8

Conclusion Our institution has a lower USS sensitivity for lower extremity DVT Sensitivity is diluted by IVDUs We recommend repeating USS for: Patients with likely Wells score and positive D-Dimers All IVDUs with negative first scan

Thank You