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

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

3. NICE Algorithm

4. 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?

5. Methods
Retrospective analysis of medical records
12 Months period

6. 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

7. Results: Study Flowchart

8. Results: All patients
Sensitivity = 132/ ( ) = 90.41%

9. Results: IVDU Flowchart

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

11. 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

12. 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

13. Thank You