ABSTRACT
Background: After mild Covid-19, a subgroup of patients reports post-acute sequelae of Covid-19 (PASC), in which exertional dyspnea and perceived exercise intolerance are common. Underlying pathophysiological mechanisms remain incompletely understood. We studied outcomes from cardiopulmonary exercise test (CPET) in these patients. Method(s): In this observational study, we included patients referred for the analysis of PASC after mild Covid-19 in whom CPET was performed after standard clinical work-up turned out unremarkable. Cardiocirculatory, ventilatory and metabolic response to, and breathing patterns during exercise at physiological limits were analyzed. Result(s): Twenty-one patients (76% female, mean age 40y) who reported severe fatigue (CIS-fatigue >= 35), dyspnea (mMRC 2 (IQR1-2)) and disability in physical role functioning (SF-36) underwent CPET at 32 weeks (IQR 22-52) after Covid-19. Mean peak oxygen uptake was 99% (SD13) of predicted with normal anaerobic thresholds at 62% (SD11) of predicted oxygen uptake. No cardiovascular or gas exchange abnormalities were detected. Twenty out of the 21 patients (95%) demonstrated breathing dysregulation, existing of ventilatory inefficiency (29%), abnormal course of breathing frequency and tidal volume (57%), and acute or chronic respiratory alkalosis in resting blood gases (67%). Conclusion(s): In the absence of deconditioning, breathing dysregulation may explain the experienced exertional dyspnea and exercise intolerance in patients with PASC after mild Covid-19.
ABSTRACT
Background: During hospitalization for Covid-19 the prevalence of pulmonary embolism (PE) is ~15%. Occult PE may be undiagnosed during hospitalization. Also, after discharge, factors such as residual (local) inflammation and relative physical inactivity may predispose to PE. Aim(s): To study the presence of occult PE and pulmonary perfusion defects three months after discharge from hospitalization for Covid-19. Method(s): In this prospective study we performed CT pulmonary angiography (CTPA) in adults three months after discharge from hospitalization for moderate-to-critical Covid-19. Exclusion criteria: therapeutic anticoagulation, diagnosed PE during hospitalization, CTPA contra-indications. Primary outcome measure was presence of PE. Secondary outcomes were wedge shaped perfusion defects on subtraction iodine maps, D-dimer concentration, presence of Years criteria at follow-up, and pulmonary parenchymal abnormalities. Result(s): 26 patients (65% male, 61 (SD10) y, hospital length of stay 11 (IQR9-15) days, 34% ICU treatment) underwent CTPA at 13 (SD2) weeks after discharge. 25 patients (96%) had no evidence for PE while one post-ICU patient demonstrated a suspected partial occlusion of a subsegmental pulmonary artery. No wedge shaped perfusion defects were found. D-Dimer values were <1000 ng/ml in all patients and none had Years criteria. Extent of parenchymal abnormalities decreased compared to acute phase (CT severity score 7 (SD5) vs 13 (SD5), p=0.004). Conclusion(s): Prevalence of occult PE three months after discharge from hospitalization for Covid-19 was negligible in our sample. CTPA should not be routinely performed in these patients. .