Persistent dyspnea after COVID-19 is not related to cardiopulmonary impairment; a cross-sectional study of persistently dyspneic COVID-19, non-dyspneic COVID-19 and controls

• Published in: Frontiers in physiology Vol. 13; p. 917886
• Main Authors: Beaudry, Rhys I, Brotto, Andrew R, Varughese, Rhea A, de Waal, Stephanie, Fuhr, Desi P, Damant, Ronald W, Ferrara, Giovanni, Lam, Grace Y, Smith, Maeve P, Stickland, Michael K
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 06.07.2022
• Subjects: DLCO; long-covid; maximal oxygen consumption; Physiology; pulmonary function; pulmonary vascular; VO2; VO2; long-covid; pulmonary function; DLCO; pulmonary vascular; maximal oxygen consumption
• ISSN: 1664-042X; 1664-042X
• DOI: 10.3389/fphys.2022.917886

Up to 53% of individuals who had mild COVID-19 experience symptoms for >3-month following infection (Long-CoV). Dyspnea is reported in 60% of Long-CoV cases and may be secondary to impaired exercise capacity (VO ) as a result of pulmonary, pulmonary vascular, or cardiac insult. This study examined whether cardiopulmonary mechanisms could explain exertional dyspnea in Long-CoV. A cross-sectional study of participants with Long-CoV (n = 28, age 40 ± 11 years, 214 ± 85 days post-infection) and age- sex- and body mass index-matched COVID-19 naïve controls (Con, n = 24, age 41 ± 12 years) and participants fully recovered from COVID-19 (ns-CoV, n = 14, age 37 ± 9 years, 198 ± 89 days post-infection) was conducted. Participants self-reported symptoms and baseline dyspnea (modified Medical Research Council, mMRC, dyspnea grade), then underwent a comprehensive pulmonary function test, cardiopulmonary exercise test, exercise pulmonary diffusing capacity measurement, and rest and exercise echocardiography. VO , pulmonary function and cardiac/pulmonary vascular parameters were not impaired in Long- or ns-CoV compared to normative values (VO : 106 ± 25 and 107 ± 25% , respectively) and cardiopulmonary responses to exercise were otherwise normal. When Long-CoV were stratified by clinical dyspnea severity (mMRC = 0 vs mMRC≥1), there were no between-group differences in VO . During submaximal exercise, dyspnea and ventilation were increased in the mMRC≥1 group, despite normal operating lung volumes, arterial saturation, diffusing capacity and indicators of pulmonary vascular pressures. Persistent dyspnea after COVID-19 was not associated with overt cardiopulmonary impairment or exercise intolerance. Interventions focusing on dyspnea management may be appropriate for Long-CoV patients who report dyspnea without cardiopulmonary impairment.