Fig. 2

Conventional and color map sCTA images within 24 h of admission to the hospital and before administration of the first dose of the allocated intervention. A Placebo Arm. 70-year-old male patient before receiving the first dose of placebo with RT-PCR-confirmed COVID-19 at 6 days since symptom onset. Admission Charlson score was 3, A-a gradient was 75.6, and PaO₂/FiO₂ ratio was 322. D-dimer was 272 ng/mL. He was admitted to the ICU, managed with IMV, and died almost 7 weeks after admission. CT severity score: 9; sCTA perfusion score: 10. Moderate lung involvement with patchy ground-glass opacities in both lungs with vascular dilatation in small peripheral subsegmental pulmonary arterial branches, some of them with a varicose appearance (black arrows). Severe hypoperfusion abnormalities in apparently normal lung parenchyma (*). Some areas of ground-glass opacities show marked hyperperfusion, most likely due to vasoplegia (white arrows). B Sildenafil Arm. 64-year-old female patient before receiving the first dose of sildenafil with RT-PCR-confirmed COVID-19 at 7 days since symptom onset. Admission Charlson score was 2, A-a gradient was 109.9, and PaO₂/FiO₂ ratio was 207. D-dimer was 308 ng/mL. She was admitted to the ICU, managed with high flow nasal cannula, and stayed in the hospital for 14 days until discharge. CT severity score: 9; sCTA perfusion score: 10. Moderate lung involvement with patchy ground-glass opacities in both lungs and laminar atelectasis (small black arrows). There is vascular dilatation in small peripheral subsegmental pulmonary arterial branches (black arrow). Severe hypoperfusion abnormalities in apparently normal lung parenchyma (*). Some areas of ground-glass opacities show marked hyperperfusion, most likely due to vasoplegia (white arrows). Linear atelectasis shows increased perfusion in lower left lobe (small black arrows)