ABSTRACT
Background: Patients recovered from COVID-19 often present with reduced exercise capacity and persistent exertional breathlessness, yet the mechanisms are still poorly understood. Method(s): We aimed to test patients formerly hospitalized for COVID-19 pneumonia with normal chest computed tomography (CT) at 6-month follow up but with persistent exertional breathlessness. Spirometry, chest CT, incremental cycle exercise test with arterial line, resting echocardiography and ventilation/perfusion (V/Q) scan were performed. Result(s): Data represents one patient and 4 healthy controls (CTRL) used for comparison. Patient (age: 41 vs. average 41.5 years in CTRL) was never smoker with FEV1 of 86 %predicted, normal chest CT and normal resting echocardiogram. Patient reported significant activity-related dyspnea (baseline dyspnea index score: 7). During exercise, peak work rate, ventilation, and oxygen update were within normal. Yet, patient had greater dyspnea intensity, ventilatory requirements and ventilatory equivalent for CO during exercise, with 4% drop in O2 saturation, 2 figure. Patient and CTRL had similar tidal volume (VT), rest-to-peak change in dead space/VT, and O2 pulse. V/Q scan showed multiple perfusion defects. Conclusion(s): Preliminary data shows that reduced ventilatory efficiency during exercise, suggesting pulmonary vascular abnormalities, could possibly explain persistent breathlessness in patients recovered from COVID pneumonia.