Pulmonary ischaemia without pulmonary arterial thrombus in COVID-19 patients receiving extracorporeal membrane oxygenation: a cohort study

AIM: To evaluate the incidence of pulmonary ischaemia in COVID-19 patients on extracorporeal membrane oxygenation (ECMO), and its correlation with pulmonary artery thrombosis. MATERIALS AND METHODS: Computed tomography (CT) thorax of all patients receiving ECMO with proven COVID-19 pneumonitis between March and May 2020 were analysed for the presence and extension of pulmonary thromboembolic disease. RESULTS: Fifty-one patients were reviewed. The mean (range) age of 45 (26–66) years; 38/51 (74.5%) were men. All patients had severe COVID-19 pneumonitis, and 18/51 (35.3%) had macroscopic thrombosis (15 with associated ischaemia); however, 13/51 (25.5%) patients had ischaemia without associated thrombus. CONCLUSION: The majority of patients with COVID-19 who received ECMO had areas of ischaemia within consolidated lungs, almost half of these without subtending pulmonary artery thrombosis. Although the prognostic significance of these findings is unclear, they are highly suggestive of lung ischaemia due to isolated microvascular immune thrombosis.