803 Characteristics of patients with COVID-19 undergoing CT pulmonary angiography in the emergency department: a retrospective observational study

Aims/Objectives/Background The shared features of pulmonary embolism (PE) and COVID-19 create a diagnostic challenge for Emergency Departments. Raised D-dimer CRP are predictive PE, critical illness mortality from COVID-19, however guidelines state there is insufficient evidence to recommend that biomarkers be used guide practice diagnose PE. This retrospective observational study analyses characteristics patients with undergoing CT angiography (CTPA) in the Department. aim establish whether role D-dimer, Wells’ score risk stratify CTPA imaging enable early diagnosis Methods/Design scans requested by two London Departments April 2020, December 2020-February 2021 were identified. Inclusion: positive PCR or radiographic appearances. Patient records screened identify: gender, age, days since symptom onset, CRP. Exclusion: >30 symptoms, chronic already receiving anticoagulation data. scores calculated diagnosed Results/Conclusions 468 included, 47 PE on (prevalence=10%). (ng/ml) significantly higher compared no (median 6154; IQR 2455-12092 v med 1221; 787-2350, p<0.05). Odds ratio ≥1000 <1000 = 26.8 (95% confidence interval: 3.66–196.29). Diagnostic testing: sensitivity 97.87%, specificity 36.82%, PPV 14.74%, NPV 99.36%. Mean PE=4 (3–7.5), 53% (n=25) having 4 less (’PE unlikely’). has strong at values than 1000ng/ml population, therefore may have ruling out reducing criteria, if according NICE guidance, would not indicate potentially lead delayed this patient group.