Persisting exercise ventilatory inefficiency in subjects recovering from COVID-19. Longitudinal data analysis 34 months post-discharge, 2024, Dorelli+

Persisting exercise ventilatory inefficiency in subjects recovering from COVID-19. Longitudinal data analysis 34 months post-discharge
Dorelli, Gianluigi; Sartori, Giulia; Fasoli, Giulia; Ridella, Nicolò; Bianchini, Nicola; Braggio, Michele; Ferrari, Marcello; Venturelli, Massimo; Carbonare, Luca Dalle; Capelli, Carlo; Grassi, Bruno; Crisafulli, Ernesto

SARS-CoV-2 infection has raised concerns about long-term health repercussions. Exercise ventilatory inefficiency (EVin) has emerged as a notable long-term sequela, potentially impacting respiratory and cardiovascular health. This study aims to assess the long-term presence of EVin after 34 months and its association with cardiorespiratory health in post-COVID patients. In a longitudinal study on 32 selected post-COVID subjects, we performed two cardiopulmonary exercise tests (CPETs) at 6 months (T0) and 34 months (T1) after hospital discharge. The study sought to explore the long-term persistence of EVin and its correlation with respiratory and cardiovascular responses during exercise.

Measurements included also VO2peak, end-tidal pressure of CO2 (PETCO2) levels, oxygen uptake efficiency slope (OUES) and other cardiorespiratory parameters, with statistical significance set at p < 0.05. The presence of EVin at both T0 and T1 defines a persisting EVin (pEVin). Out of the cohort, five subjects (16%) have pEVin at 34 months.

Subjects with pEVin, compared to those with ventilatory efficiency (Evef) have lower values of PETCO2 throughout exercise, showing hyperventilation. Evef subjects demonstrated selective improvements in DLCO and oxygen pulse, suggesting a recovery in cardiorespiratory function over time.

In contrast, those with pEvin did not exhibit these improvements. Notably, significant correlations were found between hyperventilation (measured by PETCO2), oxygen pulse and OUES, indicating the potential prognostic value of OUES and Evin in post-COVID follow-ups.

The study highlights the clinical importance of long-term follow-up for post-COVID patients, as a significant group exhibit persistent EVin, which correlates with altered and potentially unfavorable cardiovascular responses to exercise. These findings advocate for the continued investigation into the long-term health impacts of COVID-19, especially regarding persistent ventilatory inefficiencies and their implications on patient health outcomes.

Link | PDF (BMC Pulmonary Medicine) [Open Access]

 

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Some other LC studies that also used a CPET:

• Use of Cardiopulmonary Exercise Testing to Evaluate Long COVID-19 Symptoms in Adults - A Systematic Review and Meta-analysis
• Reduced exercise capacity, chronotropic incompetence, early systematic inflammation in cardiopulmonary phenotype Long COVID
• Cardiopulmonary testing in long COVID-19 versus non-COVID-19 patients with undifferentiated Dyspnea on exertion
  

 

Cohort characteristics:

32 LC patients (tested at 6 months and 34 months). These patients had all been hospitalized due to COVID-19 pneumonia during the first two waves of the pandemic in Italy.

Patients above the age of 65, a BMI above 35 and with pre-existing illnesses were mostly excluded.

Other than that I didn't see any details on the patients.

In that sense it is not clear whether this has much relevance to "Long-Covid" and indeed as the title suggests is rather a study of patients after they had Covid-19 pneumonia.

As such I don't think it's really much of a missed opportunity to not have conducted a 2-day CPET as the authors seem to be studying something else entirely (rather than ME/CFS or syndromic LC) with a focus on breathlessness in people that experienced pneumonia during a severe infection, an interesting field in its own right. The ventilo-perfusory alteration after COVID-19 references which the authors cite are mostly related to severe acute infections as far as I can see.

If anything this study once again shows that if you want to study phenomena that might not be a direct consequence of a severe acute infection it's most sensible to exclude such people from your study or even better have different cohorts with different acute infection statuses. It could be interesting to compare this data to some of the LC-CPET studies above which also included non-hospitalised patients as far as I remember.

Could be interesting to know what percentage of people are currently exercising or had undergone physical therapy as this would probably apply to most of these patients and suggest that these problems are indeed non-resolving for a subset of people who have a severe acute infection but who are considered "physically fit".

 

I have dyspnoea when walking at a slow pace during viral infections.

 

Can hypervertilation, more Co2, in exercise help to remove lactate?