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Invasive Cardiopulmonary Exercise Testing Identifies Distinct Physiologic Endotypes in Postacute Sequelae of
Michael G Risbano1,2, Corrine R Kliment1, Daniel G Dunlap1
1Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine and UPMC, Pittsburgh, PA.
CHEST Pulmonary
|August 4, 2026
Summary
Post-acute sequelae of COVID-19 (PASC) causes exercise intolerance due to various physiological issues. Invasive cardiopulmonary exercise testing (iCPET) identified distinct PASC endotypes, aiding in understanding and potentially treating these conditions.
Area of Science:
- Cardiology
- Pulmonology
- Exercise Physiology
Background:
- Exercise intolerance and dyspnea on exertion are common in post-acute sequelae of COVID-19 (PASC).
- The underlying physiological contributors to PASC-related exercise intolerance are not well understood.
- Invasive cardiopulmonary exercise testing (iCPET) is a method to evaluate exercise intolerance.
Purpose of the Study:
- To identify the distinguishing clinical and physiological features of exercise-intolerant PASC.
- To categorize patients with PASC into distinct physiological endotypes using iCPET.
Main Methods:
- A cross-sectional observational study enrolled 37 patients with PASC experiencing dyspnea or exercise intolerance.
- Patients underwent iCPET, pulmonary function testing, echocardiogram, and laboratory work.
- Detailed cardiopulmonary and hemodynamic analysis was performed to categorize PASC endotypes.
Main Results:
- Of 37 patients, 25 (67.6%) had reduced peak oxygen consumption, while 12 (32.4%) had normal exercise capacity.
- iCPET identified diverse PASC endotypes: preload insufficiency, decreased oxygen extraction, exercise pulmonary hypertension, chronic pulmonary embolism, deconditioning, and ventilatory limitation.
- Physiological abnormalities were present even in PASC patients with normal exercise capacity, including exercise pulmonary hypertension and decreased oxygen extraction.
Conclusions:
- iCPET revealed heterogeneous physiological endotypes in PASC patients with similar symptoms of exercise intolerance.
- Further research is needed to understand the pathogenesis of these endotypes and develop targeted therapies.
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