Commentary — Post-Acute Sequelae of SARS-CoV-2: More Than Deconditioning, 2023, Phillip Joseph; Inderjit Singh

[SNT Gatchaman]

Post-Acute Sequelae of SARS-CoV-2: More Than Deconditioning
Phillip Joseph; Inderjit Singh

No abstract.

Link | PDF (CHEST)

 

[SNT Gatchaman]

The majority of noninvasive CPETs are unrevealing for significant cardiopulmonary pathophysiology condition, with the conclusion that exertional intolerance in PASC may be caused by deconditioning.

We argue that deconditioning remains a diagnosis of exclusion and that further diagnostics that incorporate invasive hemodynamics may reveal the exercise pathophysiology of PASC. Invasive CPET (which combines conventional CPET ventilation and gas exchange analysis with the use of pulmonary and radial artery catheters to measure invasive hemodynamics, oxygen delivery, and systemic oxygen extraction [EO2]) offers explanations for the reduced oxygen uptake described in prior noninvasive CPET studies.

a reduction in oxygen uptake is explained by either impaired oxygen delivery caused by an inability to augment cardiac output during exercise, impaired systemic EO2, or both. After pulmonary mechanical and central cardiac limitations to exercise (ie, the absence of heart failure and pulmonary hypertension) have been ruled out, impaired systemic EO2 remains as the explanation for exertional intolerance in a cohort of patients with PASC who undergo invasive CPET.

While deconditioning is commonly suggested to cause impaired systemic EO2, this does not cause the degree of impairment observed in the aforementioned invasive CPET study. Bedrest studies demonstrate only a mild impairment of systemic EO2 with deconditioning.

Potential causes of impaired systemic EO2 include mitochondrial dysfunction and peripheral macroscopic or microscopic left-to-right shunts.

 

[Michelle]

Invasive CPET (which combines conventional CPET ventilation and gas exchange analysis with the use of pulmonary and radial artery catheters to measure invasive hemodynamics, oxygen delivery, and systemic oxygen extraction [EO2]) offers explanations for the reduced oxygen uptake described in prior noninvasive CPET studies.

Is this the first group to do iCPET aside from Systrom's group? I've been wondering why nobody else was trying to replicate Systrom's iCPET and started thinking that maybe nobody felt it was worth trying to replicate.

 

[SNT Gatchaman]

This is a commentary but they're referencing Systrom's study.