Exertional intolerance and dyspnea with preserved lung function: an emerging long COVID phenotype?

Assessment of lung function variability documents airflow limitation in many patients with long covid

Background

It is estimated that 65 million people worldwide suffer from long covid (LC). Many LC symptoms are also reported by patients with airflow limitation, used to confirm asthma. The primary aim was to detect airflow limitation in LC patients by a methacholine bronchial provocation test (BPT) and if negative, by evaluation of diurnal variability in forced expiratory flow in 1 second (FEV1) over a two-weeks' period. The second aim was to assess responsiveness to asthma treatment on diurnal FEV1 variability and LC symptoms.

Methods

Patients with LC for at least six months were recruited in this open diagnostic study. Burden of LC symptoms were reported on a 10-point Likert scale (0 = not troubled, 10 = extremely troubled) at inclusion and after three weeks' asthma treatment. A positive methacholine BPT was defined by an accumulated provocation dose (PD20)<8 μmol causing 20% fall in FEV1. App-based spirometer was used for diurnal FEV1 variability, deemed positive by diurnalvariability in FEV1 ≥12%.

Results

Airflow limitation was documented by positive methacholine BPT in 8/30 (27%), or by excessive diurnal variability in FEV1 in 21/22 (95%) of the BPT negative LC patients. One patient dropped out due to personal issues. Three weeks' asthma treatment normalised mean diurnal FEV1 variability from 18.0% to 7.3%, p < 0.001. Significant reductions were observed for fatigue and dyspnoea, from 8.3 to 6.1, p < 0.001, and 3.0 to 0, p < 0.001, respectively.

Conclusion

This study indicate that airflow limitation may be detected in many LC patients if evaluation of diurnal variability in FEV1 is included in the diagnostics.

Severe Acute Respiratory Syndrome Coronavirus 2 Did Not Substantially Impact Injury Patterns or Performance of Players in the National Basketball Association From 2016 to 2021

Purpose

To perform a descriptive epidemiologic analysis of National Basketball Association (NBA) injuries from 2016 to 2021, to evaluate the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (coronavirus disease 2019, or COVID-19) on injury patterns and performance statistics, and to determine the effect of infection with SARS-CoV-2 on individual performance statistics.

Methods

Injury epidemiology in the NBA from the 2016 to 2021 seasons was collected using a comprehensive online search. Injuries and time missed were categorized by injury location and type. Player positions and timing of injury were recorded. Performance statistics were collected including traditional game statistics and Second Spectrum (speed, distance) statistics. Comparisons were made over seasons and comparing the pre-COVID-19 pandemic seasons to the pandemic era seasons. Players diagnosed with COVID-19 were analyzed for changes in performance in the short or long term.

Results

Of the 3,040 injuries captured, 1,880 (61.84%) were in the lower extremity. Guards (77.44%) and forwards (75.88%) had a greater proportion of soft-tissue injuries (P < .001) than centers. Guards had the highest proportion of groin (3.27%, P = .001) and hamstring (6.21%, P < .001) injuries. Despite minor differences on a per-season basis, there were no differences in injury patterns identified between pre-COVID-19 and COVID-19 eras. Of players diagnosed with COVID-19 during the NBA Bubble, there were no detriments in short- or long-term performance identified, including traditional game statistics and speed and distance traveled.

Conclusions

In the NBA seasons from 2016 to 2021, most injuries were to the lower extremity. The SARS-CoV-2 pandemic did not substantially impact injury patterns in the NBA, including locations of injury and type of injury (bony or soft tissue). Furthermore, infection with SARS-CoV-2 does not appear to have a significant impact on performance in basketball-specific or speed and distance measures.

Level of Evidence

Level IV, prognostic case series.

Lung function assessment in children with Long-Covid syndrome

INTRODUCTION

A significant percentage of patients who survived the Coronavirus Infection Disease 2019 (COVID-19) showed persistent general and respiratory symptoms even months after recovery. This condition, called Post-Acute Sequelae of COVID-19 or Long-Covid syndrome (LCS), has been described also in children with positive history for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Little is known about the pathophysiologic mechanisms underlying this syndrome. The aim of this study was to investigate any difference between children with LCS and asymptomatic peers with previous COVID-19 in terms of lung function and lung ultrasound (LUS) patterns. Secondly, we tested associations between lung function abnormalities and LUS findings with Long-Covid.

METHODS

We carried out a prospective, descriptive, observational study including 58 children aged 5-17 years: 28 with LCS compared to 30 asymptomatic children with previous COVID-19. We collected demographic data, history of asthma, allergy or smoke exposure, and acute COVID-19 symptoms. After a median period of 4.5 months (1%-95% range 2-21) since the infection, lung function was assessed by spirometry, body plethysmography, diffusion lung capacity for carbon monoxide (DLCO). Airways inflammation was investigated by fractional exhaled nitric oxide (FeNO). LUS was performed independently by two experienced clinicians.

RESULTS

We found that children with LCS were older than controls (mean (SD) 12 (4.1) vs. 9.7 (2.6); p = .04). Children with LCS complained more frequently fatigue (46.4%), cough (17.9%), exercise intolerance (14.3%) and dyspnea (14.3%). Lung function was normal and similar between the two groups. The frequency of LUS abnormalities was similar between the two groups (43.3% children with LCS vs. 56.7% controls; p = .436). Children with LCS showed lower FeNO values (log difference -0.30 (CI 95% -0.50, -0.10)), but no association of LCS with a lower lung function and abnormal LUS findings was found.

CONCLUSIONS

LCS seems to be more frequent in older age children. Lung functional and structural abnormalities were not different between children with LCS and asymptomatic subjects with previous COVID-19. In addition, children with LCS showed lower FeNO values than controls, suggesting its potential role as a marker in LCS. However, further and larger studies are needed to confirm our findings.

Computable Phenotypes for Post-acute sequelae of SARS-CoV-2: A National COVID Cohort Collaborative Analysis

Post-acute sequelae of SARS-CoV-2 (PASC) is an increasingly recognized yet incompletely understood public health concern. Several studies have examined various ways to phenotype PASC to better characterize this heterogeneous condition. However, many gaps in PASC phenotyping research exist, including a lack of the following: 1) standardized definitions for PASC based on symptomatology; 2) generalizable and reproducible phenotyping heuristics and meta-heuristics; and 3) phenotypes based on both COVID-19 severity and symptom duration. In this study, we defined computable phenotypes (or heuristics) and meta-heuristics for PASC phenotypes based on COVID-19 severity and symptom duration. We also developed a symptom profile for PASC based on a common data standard. We identified four phenotypes based on COVID-19 severity (mild vs. moderate/severe) and duration of PASC symptoms (subacute vs. chronic). The symptoms groups with the highest frequency among phenotypes were cardiovascular and neuropsychiatric with each phenotype characterized by a different set of symptoms.

Structural and functional impairments of skeletal muscle in patients with postacute sequelae of SARS-CoV-2 infection

Following acute coronavirus disease 2019 (COVID-19), a substantial proportion of patients showed symptoms and sequelae for several months, namely the postacute sequelae of COVID-19 (PASC) syndrome. Major phenomena are exercise intolerance, muscle weakness, and fatigue. We aimed to investigate the physiopathology of exercise intolerance in patients with PASC syndrome by structural and functional analyses of skeletal muscle. At least 3 mo after infection, nonhospitalized patients with PASC (n = 11, age: 54 ± 11 yr; PASC) and patients without long-term symptoms (n = 12, age: 49 ± 9 yr; CTRL) visited the laboratory on four nonconsecutive days. Spirometry, lung diffusion capacity, and quality of life were assessed at rest. A cardiopulmonary incremental exercise test was performed. Oxygen consumption (V̇o2) kinetics were determined by moderate-intensity exercises. Muscle oxidative capacity (k) was assessed by near-infrared spectroscopy. Histochemical analysis, O2 flux (JO2) by high-resolution respirometry, and quantification of key molecular markers of mitochondrial biogenesis and dynamics were performed in vastus lateralis biopsies. Pulmonary and cardiac functions were within normal range in all patients. V̇o2peak was lower in PASC than CTRL (24.7 ± 5.0 vs. 32.9 ± 7.4 mL·min-1·kg-1, respectively, P < 0.05). V̇o2 kinetics was slower in PASC than CTRL (41 ± 12 vs. 30 ± 9 s-1, P < 0.05). k was lower in PASC than CTRL (1.54 ± 0.49 vs. 2.07 ± 0.51 min-1, P < 0.05). Citrate synthase, peroxisome proliferator-activated receptor-γ coactivator (PGC)1α, and JO2 for mitochondrial complex II were significantly lower in PASC vs. CTRL (all P values <0.05). In our cohort of patients with PASC, we showed limited exercise tolerance mainly due to "peripheral" determinants. Substantial reductions were observed for biomarkers of mitochondrial function, content, and biogenesis. PASC syndrome, therefore, appears to negatively impact skeletal muscle function, although the disease is a heterogeneous condition.NEW & NOTEWORTHY Several months after mild acute SARS-CoV-2 infection, a substantial proportion of patients present persisting, and often debilitating, symptoms and sequelae. These patients show reduced quality of life due to exercise intolerance, muscle weakness, and fatigue. The present study supports the hypothesis that "peripheral" impairments at skeletal muscle level, namely, reduced mitochondrial function and markers of mitochondrial biogenesis, are major determinants of exercise intolerance and fatigue, "central" phenomena at respiratory, and cardiac level being less relevant.

Dyspnea in Post-Acute COVID-19: A Multi-Parametric Cardiopulmonary Evaluation

Post-acute COVID-19 is characterized by the persistence of dyspnea, but the pathophysiology is unclear. We evaluated the prevalence of dyspnea during follow-up and factors at admission and follow-up associated with dyspnea persistence. After five months from discharge, 225 consecutive patients hospitalized for moderate to severe COVID-19 pneumonia were assessed clinically and by laboratory tests, echocardiography, six-minute walking test (6MWT), and pulmonary function tests. Fifty-one patients reported persistent dyspnea. C-reactive protein (p = 0.025, OR 1.01 (95% CI 1.00-1.02)) at admission, longer duration of hospitalization (p = 0.005, OR 1.05 (95% CI 1.01-1.10)) and higher body mass index (p = 0.001, OR 1.15 (95% CI 1.06-1.28)) were independent predictors of dyspnea. Absolute drop in SpO₂ at 6MWT (p = 0.001, OR 1.37 (95% CI 1.13-1.69)), right ventricular (RV) global longitudinal strain (p = 0.016, OR 1.12 (95% CI 1.02-1.25)) and RV global longitudinal strain/systolic pulmonary artery pressure ratio (p = 0.034, OR 0.14 (95% CI 0.02-0.86)) were independently associated with post-acute COVID-19 dyspnea. In conclusion, dyspnea is present in many patients during follow-up after hospitalization for COVID-19 pneumonia. While higher body mass index, C-reactive protein at admission, and duration of hospitalization are predictors of persistent dyspnea, desaturation at 6MWT, and echocardiographic RV dysfunction are associated with this symptom during the follow-up period.

Deduced Respiratory Scores on COVID-19 Patients Learning from Exertion-Induced Dyspnea

Dyspnea is one of the most common symptoms of many respiratory diseases, including COVID-19. Clinical assessment of dyspnea relies mainly on self-reporting, which contains subjective biases and is problematic for frequent inquiries. This study aims to determine if a respiratory score in COVID-19 patients can be assessed using a wearable sensor and if this score can be deduced from a learning model based on physiologically induced dyspnea in healthy subjects. Noninvasive wearable respiratory sensors were employed to retrieve continuous respiratory characteristics with user comfort and convenience. Overnight respiratory waveforms were collected on 12 COVID-19 patients, and a benchmark on 13 healthy subjects with exertion-induced dyspnea was also performed for blind comparison. The learning model was built from the self-reported respiratory features of 32 healthy subjects under exertion and airway blockage. A high similarity between respiratory features in COVID-19 patients and physiologically induced dyspnea in healthy subjects was observed. Learning from our previous dyspnea model of healthy subjects, we deduced that COVID-19 patients have consistently highly correlated respiratory scores in comparison with normal breathing of healthy subjects. We also performed a continuous assessment of the patient's respiratory scores for 12-16 h. This study offers a useful system for the symptomatic evaluation of patients with active or chronic respiratory disorders, especially the patient population that refuses to cooperate or cannot communicate due to deterioration or loss of cognitive functions. The proposed system can help identify dyspneic exacerbation, leading to early intervention and possible outcome improvement. Our approach can be potentially applied to other pulmonary disorders, such as asthma, emphysema, and other types of pneumonia.

Thoracic Ultrasound in COVID-19: Use of Lung and Diaphragm Ultrasound in Evaluating Dyspnea in Survivors of Acute Respiratory Distress Syndrome from COVID-19 Pneumonia in a Post-ICU Clinic

INTRODUCTION

Dyspnea is a common symptom in survivors of severe COVID-19 pneumonia. While frequently employed in hospital settings, the use of point-of-care ultrasound in ambulatory clinics for dyspnea evaluation has rarely been explored. We aimed to determine how lung ultrasound score (LUS) and inspiratory diaphragm excursion (DE) correlate with patient-reported dyspnea during a 6-min walk test (6MWT) in survivors of COVID-19 acute respiratory distress syndrome (ARDS). We hypothesize higher LUS and lower DE will correlate with dyspnea severity.

STUDY DESIGN AND METHODS

Single-center cross-sectional study of survivors of critically ill COVID-19 pneumonia (requiring high-flow nasal cannula, invasive, or non-invasive mechanical ventilation) seen in our Post-ICU clinic. All patients underwent standardized scanning protocols to compute LUS and DE. Pearson correlations were performed to detect an association between LUS and DE with dyspnea at rest and exertion during 6MWT.

RESULTS

We enrolled 45 patients. Average age was 61.5 years (57.7% male), with average BMI of 32.3 Higher LUS correlated significantly with dyspnea, at rest (r =  + 0.41, p =  < 0.01) and at exertion (r =  + 0.40, p =  < 0.01). Higher LUS correlated significantly with lower oxygen saturation during 6MWT (r = -0.55, p =  < 0.01) and lower 6MWT distance (r = -0.44, p =  < 0.01). DE correlated significantly with 6MWT distance but did not correlate with dyspnea at rest or exertion.

CONCLUSION

Higher LUS correlated significantly with patient-reported dyspnea at rest and exertion. Higher LUS significantly correlated with more exertional oxygen desaturation during 6MWT and lower 6MWT distance. DE did not correlate with dyspnea.

Post-COVID dyspnea: prevalence, predictors, and outcomes in a longitudinal, prospective cohort

BACKGROUND

The pathophysiology, evolution, and associated outcomes of post-COVID dyspnea remain unknown. The aim of this study was to determine the prevalence, severity, and predictors of dyspnea 12 months following hospitalization for COVID-19, and to describe the respiratory, cardiac, and patient-reported outcomes in patients with post-COVID dyspnea.

METHODS

We enrolled a prospective cohort of all adult patients admitted to 2 academic hospitals in Vancouver, Canada with PCR-confirmed SARS-CoV-2 during the first wave of COVID between March and June 2020. Dyspnea was measured 3, 6, and 12 months after initial symptom onset using the University of California San Diego Shortness of Breath Questionnaire.

RESULTS

A total of 76 patients were included. Clinically meaningful dyspnea (baseline score > 10 points) was present in 49% of patients at 3 months and 46% at 12 months following COVID-19. Between 3 and 12 months post-COVID-19, 24% patients had a clinically meaningful worsening in their dyspnea, 49% had no meaningful change, and 28% had a clinically meaningful improvement in their dyspnea. There was worse sleep, mood, quality of life, and frailty in patients with clinically meaningful dyspnea at 12 months post-COVID infection compared to patients without dyspnea. There was no difference in PFT findings, troponin, or BNP comparing patients with and without clinically meaningful dyspnea at 12 months. Severity of dyspnea and depressive symptoms at 3 months predicted severity of dyspnea at 12 months.

CONCLUSIONS

Post-COVID dyspnea is common, persistent, and negatively impacts quality of life. Mood abnormalities may play a causative role in post-COVID dyspnea in addition to potential cardiorespiratory abnormalities. Dyspnea and depression at initial follow-up predict longer-term post-COVID dyspnea, emphasizing that standardized dyspnea and mood assessment following COVID-19 may identify patients at high risk of post-COVID dyspnea and facilitating early and effective management.

Functional outcomes in post Covid-19 patients with persistent dyspnea: multidisciplinary approach

BACKGROUND

Post-acute sequelae of SARS-CoV-2 (PASC) have emerged as a major health issue in patients who have previously been infected with Covid-19 virus.

PURPOSE

we aimed at the assessment of functional outcomes in post Covid-19 patients with persistent dyspnea using a multidisciplinary approach including clinical assessment, laboratory investigations, exercise ECG, and different echo-Doppler modalities, including left atrial functions.

METHODS

The current observational randomized controlled study conducted on 60- patients one month after recovery from Covid-19 infection presented with persistent dyspnea compared to 30 healthy volunteers. All participants were subjected to evaluation of dyspnea by different scores, laboratory investigations, stress ECG, and echo-Doppler examination to measure LV dimensions, volumes, systolic and diastolic functions by M-mode, 2D, and tissue Doppler imaging in addition to 2-D speckle tacking LA strain.

RESULTS

Post Covid-19 patients had persistent elevation of inflammatory markers, low functional capacity (evidenced by a higher NYHA class, m MRC score, PCFS scale) and decreased METs by stress ECG compared to control group. Post Covid-19 patients showed LV diastolic dysfunction and impairment of 2D-STE LA functions compared to control group. We found negative correlations between LA strain with NYHA class, mMRC scale, LAVI, ESR and CRP; meanwhile, there were significant positive correlations between LA strain with exercise duration and METs.

CONCLUSION

post Covid patients presented with persistent dyspnea demonstrated low functional capacity evidenced by different scores and stress ECG. Moreover, patients with post Covid syndrome showed elevated inflammatory biomarkers, LV diastolic dysfunction in addition to impaired LA strain functions. Impairment of LA strain was closely correlated to different functional scores, inflammatory biomarkers, exercise duration, and METs suggesting that these could to be the possible etiologies for the persistence of post Covid symptoms.

Epidemiology of post-COVID conditions beyond 1 year: a cross-sectional study

OBJECTIVE

The aim of this study was to investigate the epidemiology of post-COVID conditions beyond 12 months and identify factors associated with the persistence of each condition.

STUDY DESIGN

This was a cross-sectional questionnaire-based survey.

METHODS

We conducted the survey among patients who had recovered from COVID-19 and visited our institute between February 2020 and November 2021. Demographic and clinical data and data regarding the presence and duration of post-COVID conditions were obtained. We identified factors associated with the persistence of post-COVID conditions using multivariable linear regression analyses.

RESULTS

Of 1148 surveyed patients, 502 completed the survey (response rate, 43.7%). Of these, 393 patients (86.4%) had mild disease in the acute phase. The proportion of participants with at least one symptom at 6, 12, 18, and 24 months after symptom onset or COVID-19 diagnosis was 32.3% (124/384), 30.5% (71/233), 25.8% (24/93), and 33.3% (2/6), respectively. The observed associations were as follows: fatigue persistence with moderate or severe COVID-19 (β = 0.53, 95% confidence interval [CI] = 0.06-0.99); shortness of breath with moderate or severe COVID-19 (β = 1.39, 95% CI = 0.91-1.87); cough with moderate or severe COVID-19 (β = 0.84, 95% CI = 0.40-1.29); dysosmia with being female (β = -0.57, 95% CI = -0.97 to -0.18) and absence of underlying medical conditions (β = -0.43, 95% CI = -0.82 to -0.05); hair loss with being female (β = -0.61, 95% CI = -1.00 to -0.22), absence of underlying medical conditions (β = -0.42, 95% CI = -0.80 to 0.04), and moderate or severe COVID-19 (β = 0.97, 95% CI = 0.41-1.54); depressed mood with younger age (β = -0.02, 95% CI = -0.04 to -0.004); and loss of concentration with being female (β = -0.51, 95% CI = -0.94 to -0.09).

CONCLUSIONS

More than one-fourth of patients after recovery from COVID-19, most of whom had had mild disease in the acute phase, had at least one symptom at 6, 12, 18, and 24 months after onset of COVID-19, indicating that not a few patients with COVID-19 suffer from long-term residual symptoms, even in mild cases.

Post-COVID-19 Syndrome Comprehensive Assessment: From Clinical Diagnosis to Imaging and Biochemical-Guided Diagnosis and Management

The COVID-19 outbreak was first reported in 2019, causing massive morbidity and mortality. The majority of the COVID-19 patients survived and developed Post-COVID-19 Syndrome (PC19S) of varying severity. Currently, the diagnosis of PC19S is achieved through history and symptomatology that cannot be explained by an alternative diagnosis. However, the heavy reliance on subjective reporting is prone to reporting errors. Besides, there is no unified diagnostic assessment tool to classify the clinical severity of patients. This leads to significant difficulties when managing patients in terms of public resource utilization, clinical progression monitorization and rehabilitation plan formulation. This narrative review aims to review current evidence of diagnosis based on triple assessment: clinical symptomatology, biochemical analysis and imaging evidence. Further assessment tools can be developed based on triple assessment to monitor patient's clinical progression, prognosis and intervals of monitoring. It also highlights the high-risk features of patients for closer and earlier monitoring. Rehabilitation programs and related clinical trials are evaluated; however, most of them focus on cardiorespiratory fitness and psychiatric presentations such as anxiety and depression. Further research is required to establish an objective and comprehensive assessment tool to facilitate clinical management and rehabilitation plans.

Breathlessness and exercise with virtual reality system in long-post-coronavirus disease 2019 patients

Long-post-coronavirus disease-2019 (COVID-19) patients tend to claim residual symptomatology from various systems, most importantly the respiratory and central nervous systems. Breathlessness and brain fog are the main complaints. The pulmonary function pattern is consistent with restrictive defects, which, in most cases, are self-resolved, while the cognitive profile may be impaired. Rehabilitation is an ongoing field for holistic management of long-post-COVID-19 patients. Virtual reality (VR) applications may represent an innovative implementation of rehabilitation. We aimed to investigate the effect of exercise with and without the VR system and to assess further breathlessness and functional fitness indicators in long-post-COVID-19 patients with mild cognitive impairment after self-selected exercise duration using the VR system. Twenty long-post-COVID-19 patients were enrolled in our study (age: 53.9 ± 9.1 years, male: 80%, body mass index: 28.1 ± 3.1 kg/m²). Participants' anthropometric data were recorded, and they underwent pulmonary functional test evaluation as well as sleep quality and cognitive assessment. The participants randomly exercised with and without a VR system (VR vs. no-VR) and, later, self-selected the exercise duration using the VR system. The results showed that exercise with VR resulted in a lower dyspnea score than exercise without VR. In conclusion, VR applications seem to be an attractive and safe tool for implementing rehabilitation. They can enhance performance during exercise and benefit patients with both respiratory and cognitive symptoms.

Long-term dyspnea, regional ventilation distribution and peripheral lung function in COVID-19 survivors: a 1 year follow up study

Background

Dyspnea is common after COVID-19 pneumonia and can be characterized by a defective CO2 diffusion (DLCO) despite normal pulmonary function tests (PFT). Nevertheless, DLCO impairment tends to normalize at 1 year, with no dyspnea regression. The altered regional distribution of ventilation and a dysfunction of the peripheral lung may characterize dyspnea at 1 year after COVID-19 pneumonia. We aimed at assessing the pattern of airway resistance and inflammation and the regional ventilation inhomogeneity in COVID-19 pneumonia survivors at 12-months after hospital discharge.

Methods

We followed up at 1-year patients previously admitted to the respiratory units (intensive care or sub-intensive care unit) for COVID-19 acute respiratory failure at 1-year after hospital discharge. PFT (spirometry, DLCO), impulse oscillometry (IOS), measurements of the exhaled nitric oxide (FENO) and Electrical Impedance Tomography (EIT) were used to evaluate lung volumes, CO2 diffusion capacity, peripheral lung inflammation/resistances and the regional inhomogeneity of ventilation distribution. A full medical examination was conducted, and symptoms of new onset (not present before COVID-19) were recorded. Patients were therefore divided into two groups based on the presence/absence of dyspnea (defined as mMRC ≥1) compared to evaluate differences in the respiratory function derived parameters.

Results

Sixty-seven patients were admitted between October and December 2020. Of them, 42/67 (63%) patients were discharged alive and 33 were evaluated during the follow up. Their mean age was 64 ± 11 years and 24/33 (73%) were males. Their maximum respiratory support was in 7/33 (21%) oxygen, in 4/33 (12%) HFNC, in 14/33 (42%) NIV/CPAP and in 8/33 (24%) invasive mechanical ventilation. During the clinical examination, 15/33 (45%) reported dyspnea. When comparing the two groups, no significant differences were found in PFT, in the peripheral airway inflammation (FENO) or mechanical properties (IOS). However, EIT showed a significantly higher regional inhomogeneity in patients with dyspnea both during resting breathing (0.98[0.96–1] vs 1.1[1–1.1], p = 0.012) and during forced expiration (0.96[0.94–1] vs 1 [0.98–1.1], p = 0.045).

Conclusions

New onset dyspnea characterizes 45% of patients 1 year after COVID-19 pneumonia. In these patients, despite pulmonary function test may be normal, EIT shows a higher regional inhomogeneity both during quiet and forced breathing which may contribute to dyspnea.

Clinical trial registration

Clinicaltrials.gov NCT04343053, registration date 13/04/2020.

Relationship between the severity of persistent symptoms, physical fitness, and cardiopulmonary function in post-COVID-19 condition. A population-based analysis

The aim of this study was to determine the relationship between physical fitness, cardiopulmonary function and patient-reported severity of symptoms in people with post-COVID-19 condition. We examined ambulatory patients (n = 72) with post-COVID-19 condition who had a chronic symptomatic phase lasting > 12 weeks from the onset of symptoms, but had not been hospitalized for acute COVID-19. A comprehensive medical screening was conducted, including clinical history, symptomatology, comorbidities, body composition and physical activity levels. We then identified the relationship between physical fitness (cardiorespiratory fitness and muscular strength), cardiopulmonary function (echocardiographic and spirometry parameters) and patient-reported severity of symptoms (fatigue, dyspnea, health-related quality of life, anxiety, and depression). Age, body mass index, sex, number of comorbidities and duration of symptoms were included as potential confounders. Results showed that greater physical fitness and cardiopulmonary function were associated with lower severity of symptoms in people with post-COVID-19 condition. Cardiorespiratory fitness, lower-limb muscle strength, maximal voluntary ventilation and left ventricular ejection fraction account for reducing fatigue and dyspnea. Greater physical activity levels were associated with fewer symptoms and less-severe fatigue and dyspnea. In conclusion, preserving better cardiopulmonary health and physical condition during the course of the disease-even in mild cases-was related to a lower intensity of symptoms in non-hospitalized people with post-COVID-19 condition. It is probable that exercise and physical conditioning are valuable pre- and post-COVID-19 countermeasures that could help decrease the severity, not only of acute infection, but of post-COVID-19 persistent symptoms and prognosis.

Body Weight May Have a Role on Neuropathy and Mobility after Moderate to Severe COVID-19: An Exploratory Study

Background and Objectives: Among the extra-pulmonary manifestations of COVID-19, neuromuscular signs and symptoms are frequent. We aimed to assess the correlation between neuromuscular abnormalities (electrophysiological) and mobility measures (Berg Balance Scale and Timed-Up-and-Go test) twice, at least 6 weeks after hospital discharge and 6 months later, taking into account cognitive performance, nutrition, muscle strength, and submaximal exercise capacity. Materials and Methods: 43 patients (51.4 ± 9.3 years old) accepted to participate in the study; they had a dyspnea score ≤ 3 (Borg scale), and no history of neurology/neuromuscular/orthopedic disorders, but high frequency of overweight/obesity and weight loss during hospital stay. The two evaluations included physical examination, cognitive assessment, nutritional evaluation, muscle strength (hand-grip and quadriceps dynamometry), electromyography, Barthel Index, Six-Minute- Walk-Test (6MWT), Berg Balance Scale and Timed-Up-and-Go test. Bivariate and repeated measures covariance analyses were performed (significance level of 0.05). Results: Electrophysiological abnormalities were evident in 67% of the patients, which were associated with diminished performance on the 6MWT, the Berg Balance Scale and the Timed-Up-and-Go test. At each evaluation and between evaluations, scores on the Berg Balance Scale were related to the body mass index (BMI) at hospital admission and the 6MWT (MANCoVA R ≥ 0.62, p = 0.0001), while the time to perform the Timed-Up-and-Go test was related to the electrophysiological abnormalities, weight loss during hospital stay, sex, handgrip strength, and the 6MWT (MANCoVA, R ≥ 0.62, p < 0.0001). We concluded that, after hospital discharge, patients with moderate to severe COVID-19 may have neuromuscular abnormalities that can be related to BMI/weight loss, and contribute to mobility decrease. In patients with moderate to severe COVID-19 and high BMI/ large weight loss, neuromuscular and intended mobility assessments could be required to provide early rehabilitation. Apart from the 6MWT, handgrip dynamometry and the Timed-Up-and-Go test were useful tools to quickly assess fitness and mobility.

Cardiac impairments in postacute COVID-19 with sustained symptoms: A review of the literature and proof of concept

Although acute COVID-19 is known to cause cardiac damage in some cases, there is still much to learn about the duration and relative permanence of the damage that may occur. Long COVID is a condition that can occur when COVID-19 symptoms remain in the postviral acute period. Varying accounts of long COVID have been described across the literature, however, cardiac impairments are sustained in many individuals and cardiovascular assessment is now considered to be an expected follow-up examination. The purpose of this review and proof of concept is to summarize the current research related to the assessment of cardiac function, including echocardiography and blood biomarker data, during the follow-up period in patients who recovered from COVID-19. Following a literature review, it was found that right ventricular dysfunction along with global longitudinal strain and diastolic dysfunction are common findings. Finally, more severe acute myocardial injury during the index hospitalization appears to exacerbate cardiac function. The available literature implies that cardiac function must be monitored in patients recovered from COVID-19 who remain symptomatic and that the impairments and severity vary from person-to-person. The proof-of-concept analysis of patients with cardiac disease and respiratory disease in comparison to those with sustained symptoms from COVID-19 suggests elevated systolic time interval in those with sustained symptoms from COVID-19, thus reducing heart performance indices. Future research must consider the details of cardiac complications during the acute infection period and relate this to the cardiac function in patients with long COVID during mid- and long-term follow-up.

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

Background: 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_2peak) as a result of pulmonary, pulmonary vascular, or cardiac insult. This study examined whether cardiopulmonary mechanisms could explain exertional dyspnea in Long-CoV.

Methods: 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.

Results: VO_2peak, pulmonary function and cardiac/pulmonary vascular parameters were not impaired in Long- or ns-CoV compared to normative values (VO_2peak: 106 ± 25 and 107 ± 25%_predicted, 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_2peak. 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.

Interpretation: 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.

Respiratory muscle dysfunction in long-COVID patients

Purpose

Symptoms often persistent for more than 4 weeks after COVID-19—now commonly referred to as ‘Long COVID’. Independent of initial disease severity or pathological pulmonary functions tests, fatigue, exertional intolerance and dyspnea are among the most common COVID-19 sequelae. We hypothesized that respiratory muscle dysfunction might be prevalent in persistently symptomatic patients after COVID-19 with self-reported exercise intolerance.

Methods

In a small cross-sectional pilot study (n = 67) of mild-to-moderate (nonhospitalized) and moderate-to-critical convalescent (formerly hospitalized) patients presenting to our outpatient clinic approx. 5 months after acute infection, we measured neuroventilatory activity P0.1, inspiratory muscle strength (PImax) and total respiratory muscle strain (P0.1/PImax) in addition to standard pulmonary functions tests, capillary blood gas analysis, 6 min walking tests and functional questionnaires.

Results

Pathological P0.1/PImax was found in 88% of symptomatic patients. Mean PImax was reduced in hospitalized patients, but reduced PImax was also found in 65% of nonhospitalized patients. Mean P0.1 was pathologically increased in both groups. Increased P0.1 was associated with exercise-induced deoxygenation, impaired exercise tolerance, decreased activity and productivity and worse Post-COVID-19 functional status scale. Pathological changes in P0.1, PImax or P0.1/PImax were not associated with pre-existing conditions.

Conclusions

Our findings point towards respiratory muscle dysfunction as a novel aspect of COVID-19 sequelae. Thus, we strongly advocate for systematic respiratory muscle testing during the diagnostic workup of persistently symptomatic, convalescent COVID-19 patients.

Ongoing Exercise Intolerance Following COVID-19: A Magnetic Resonance-Augmented Cardiopulmonary Exercise Test Study

Background Ongoing exercise intolerance of unclear cause following COVID-19 infection is well recognized but poorly understood. We investigated exercise capacity in patients previously hospitalized with COVID-19 with and without self-reported exercise intolerance using magnetic resonance-augmented cardiopulmonary exercise testing. Methods and Results Sixty subjects were enrolled in this single-center prospective observational case-control study, split into 3 equally sized groups: 2 groups of age-, sex-, and comorbidity-matched previously hospitalized patients following COVID-19 without clearly identifiable postviral complications and with either self-reported reduced (COVID_reduced) or fully recovered (COVID_normal) exercise capacity; a group of age- and sex-matched healthy controls. The COVID_reducedgroup had the lowest peak workload (79W [Interquartile range (IQR), 65-100] versus controls 104W [IQR, 86-148]; P=0.01) and shortest exercise duration (13.3±2.8 minutes versus controls 16.6±3.5 minutes; P=0.008), with no differences in these parameters between COVID_normal patients and controls. The COVID_reduced group had: (1) the lowest peak indexed oxygen uptake (14.9 mL/minper kg [IQR, 13.1-16.2]) versus controls (22.3 mL/min per kg [IQR, 16.9-27.6]; P=0.003) and COVID_normal patients (19.1 mL/min per kg [IQR, 15.4-23.7]; P=0.04); (2) the lowest peak indexed cardiac output (4.7±1.2 L/min per m²) versus controls (6.0±1.2 L/min per m²; P=0.004) and COVID_normal patients (5.7±1.5 L/min per m²; P=0.02), associated with lower indexed stroke volume (SVi:COVID_reduced 39±10 mL/min per m² versus COVID_normal 43±7 mL/min per m² versus controls 48±10 mL/min per m²; P=0.02). There were no differences in peak tissue oxygen extraction or biventricular ejection fractions between groups. There were no associations between COVID-19 illness severity and peak magnetic resonance-augmented cardiopulmonary exercise testing metrics. Peak indexed oxygen uptake, indexed cardiac output, and indexed stroke volume all correlated with duration from discharge to magnetic resonance-augmented cardiopulmonary exercise testing (P<0.05). Conclusions Magnetic resonance-augmented cardiopulmonary exercise testing suggests failure to augment stroke volume as a potential mechanism of exercise intolerance in previously hospitalized patients with COVID-19. This is unrelated to disease severity and, reassuringly, improves with time from acute illness.

Long COVID: current status in Japan and knowledge about its molecular background

Even after recovering from coronavirus disease 2019 (COVID-19), patients can experience prolonged complaints, referred to as "long COVID". Similar to reports in Caucasians, a follow-up study in Japan revealed that fatigue, dyspnea, cough, anosmia/dysgeusia, and dyssomnia are common symptoms. Although the precise mode of long COVID remains elusive, multiple etiologies such as direct organ damage by infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), autoimmunity, prolonged inflammatory reactions, and psychiatric impairment seem to be involved. Notably, SARS-CoV-2 is neurotropic, and viral RNA and proteins are continuously detectable in multiple organs, including the brain. Viral proteins exert a number of different toxic effects on cells, suggesting that persistent infection is a key element for understanding long COVID. Here, we first reviewed the current status of long COVID in Japan, and then summarized literature that help us understand the molecular background of the symptoms. Finally, we discuss the feasibility of vaccination as a treatment for patients with long COVID.

The effectiveness of pulmonary rehabilitation for Post-COVID symptoms: A rapid review of the literature

BACKGROUND

Multi-disciplinary rehabilitation is recommended for individuals with post-acute sequelae of COVID-19 infection (i.e., symptoms 3-4 weeks after acute infection). There are emerging reports of use of pulmonary rehabilitation (PR) in the post-acute stages of COVID-19, however the appropriateness of PR for managing post-COVID symptoms remains unclear. To offer practical guidance with regards to post-COVID PR, a greater understanding of the clinical effectiveness literature is required.

METHODS

A rapid review of the published literature was completed. An electronic database search of the literature published between July 1, 2020 and June 1, 2021 was performed in MEDLINE, Pubmed, and EMBASE. Primary studies evaluating the clinical effectiveness of PR for individuals with post-COVID symptoms were included.

RESULTS

Nine studies evaluating the effectiveness of PR were identified; most were small, experimental or quasi-experimental studies, including 1 RCT, and were primarily of low quality. After attending PR, all studies reported improvements in exercise capacity, pulmonary function, and/or quality of life for individuals with post-COVID symptoms who had been hospitalized for their acute COVID-19 infection. Few studies evaluated changes in post-COVID symptom severity or frequency and, of these, improvements in dyspnea, fatigue, anxiety and depression were observed following PR. Further, no studies evaluated non-hospitalized patients or long-term outcomes beyond 3 months after initiating PR.

CONCLUSIONS

With limited high-quality evidence, any recommendations or practical guidance for PR programmes for those with post-COVID symptoms should consider factors such as feasibility, current PR capacity, and resource constraints.

Chronotropic Incompetence in Non-Hospitalized Patients with Post-COVID-19 Syndrome

Patients recovering from COVID-19 commonly report persistence of dyspnea, exertional fatigue, and difficulties in carrying out their daily activities. However, the nature of these symptoms is still unknown. The purpose of the study was to identify limiting causes of cardiopulmonary origin for the performance of physical exercise in post-COVID-19 condition that could explain the symptomatic persistence of dyspnea or fatigue-related symptoms. Thirty-two non-hospitalized patients with post-COVID-19 condition (i.e., still presenting a chronic symptomatic phase lasting >90 days since debut of symptoms that lasted for at least 2 months and cannot be explained by an alternative diagnosis) completed a clinical examination including echocardiography, submaximal and maximal cardiorespiratory fitness tests (Ekblom-Bak and Bruce’s protocols), and a battery of validated questionnaires about fatigue and exercise intolerance. Four participants (12.5%) reported an abnormal cardiac response to exercise during the submaximal test, which aroused suspicion of the presence of chronotropic incompetence. All of them were confirmed with a positive diagnosis maximal exercise test after cardiology screening, even with a comprehensive clinical examination, resting ECG, and echocardiogram, without other findings. No statistical differences were found in any physiological variables or questionnaire values, between patients with positive and negative diagnoses. Chronotropic incompetence and other autonomic disorders may appear in patients with mild forms of COVID-19 presentation and may persist in the long term, being responsible for exercise intolerance after resolution of acute infection. Clinicians should be aware that chronotropic incompetence and other autonomic disorders may be a complication of COVID-19 and should consider appropriate diagnostic and therapeutic interventions in these patients, especially when early exercise-related fatigability is reported.