Pulmonary Vascular Dysfunction as a Cause of Persistent Exertional Dyspnea After Coronavirus Disease (COVID-19)

Inclusion Criteria:

• Age ≥ 18 years, patients with a suspected diagnosis of post/long-COVID-19 syndromewho present to our pneumology or infectious disease outpatient clinic orcorresponding ward from the start of the study and whose SARS-CoV-2 infection wasdiagnosed at least 3 and not longer than 18 months prior to presentation

• Patients at least 3 and not longer than 18 months after a SARS-CoV-2 infectionwithout post/long-COVID-19 syndrome who present to our post-infection outpatientclinic for follow-up

Exclusion Criteria:

• Patients who refuse to participate in the study

• Severe underlying chronic pulmonary, cardiac, or systemic disease (e.g., Chronicobstructive pulmonary disease (COPD), severe heart failure, neuromuscular disease)that was diagnosed prior to acute COVID-19 disease and whose progression appearslikely as the cause of dyspnea

• Other non pneumologic causes of dyspnea (e.g., hemoglobin < 100 g/L)

• Unstable or acute disease (e.g., acute infection, acute renal failure, acutecoronary syndrome)

• Inability to perform spiroergometry, including transient orthopedic problems,contraindications to central venous and arterial catheter placement (e.g., severebleeding tendency).