Role of Combined CT Pulmonary Angiography and Indirect CT Venography in Diagnosing Venous Thromboembolism in COVID-19 Patients - Experience From an Indian Quaternary Centre.

Objectives: To study the role of combined CTPA and indirect CT venogram to diagnose venous thromboembolism (VTE) in patients with COVID-19 pneumonia and to compare the clinical characteristics, laboratory parameters, CT findings and clinical outcomes between the VTE positive and negative groups.
Methods: In this retrospective study, 131 patients with COVID-19 pneumonia who underwent CTPA and venogram between August 2020 and January 2021 were included. Relevant demographical, clinical and laboratory data and CT images were collected. Two thoracic radiologists independently reviewed the CTPA and venogram images.
Results: VTE was identified in 29 patients (22% of the study population). CT venogram identified DVT in 9 patients. No statistical difference was observed between the two groups with respect to age, gender, BMI and presence of comorbidities. There was a significant difference in the hospital stay duration, which is increased in the VTE positive group. The number of patients who were dependent on oxygen and mortality were also high in the positive group. There was statistically significant difference in the mean D-dimer value and the mean Neutrophil/lymphocyte ratio, which were higher in the VTE positive group.
Conclusion: Combined CTPA and venogram can be used as a one-stop investigation for diagnosing PE and DVT of lower limbs in patients with COVID-19 pneumonia. CTPA with venogram should be performed in patients with D-dimer value in the range of 1000 - 1200 μg/L and above to rule out VTE as the hospital stay duration and final outcomes vary between the positive and negative groups.