Background: Pulmonary embolism (PE) is a known complication of COVID-19 disease. The mechanism of thromboembolic events appears to be stimulated by excessive thrombin production, inhibition of fibrinolysis and deposition of antiphospholipids and thrombi, as well as microvascular dysfunction in multiple vascular beds. The occurrence of PE has been well demonstrated in hospitalised patients with severe disease. Very few data are available on its incidence or prevalence in non-hospitalised patients diagnosed with a milder form of the disease.
Objectives: To assess the prevalence of PE in non-hospitalised patients diagnosed with mild COVID-19 who presented with raised D-dimer levels and persistent or new-onset cardiopulmonary symptoms.
Methods: This was a retrospective study conducted in the Department of Nuclear Medicine at Universitas Academic Hospital, Bloemfontein, South Africa. We reviewed the studies of 65 non-hospitalised patients with COVID-19 referred to the department from July 2020 to January 2021 for a perfusion-only single-photon emission computed tomography/computed tomography (SPECT/CT) study or a ventilation/perfusion (VQ) SPECT/CT study. All 65 patients had raised D-dimer levels with persistent, worsening or new-onset cardiopulmonary symptoms after the diagnosis of COVID-19.
Results: Sixty-five patients were studied. The median (interquartile range) age was 46 (41 - 54) years and the majority (88.2%) were female. There were 22 patients (33.8%) with lung perfusion defects in keeping with PE. Two of these patients had a false-negative computed tomography pulmonary angiography (CTPA) study for PE performed the same day as their VQ SPECT/CT study.
Conclusions: We confirm a high prevalence of PE in non-hospitalised patients diagnosed with mild COVID-19 who presented with raised D-dimer levels and persistent or new-onset cardiopulmonary symptoms. We recommend that irrespective of disease severity, hospitalised and non-hospitalised patients with COVID-19 presenting with persistent or new-onset cardiopulmonary symptoms and raised D-dimer levels should be investigated further for PE.