Pulmonary hypertension (PH) is classified according to the Nice Classification into different etiologies, including pulmonary arterial hypertension (PAH), a disease of the pulmonary arteriolar vasculature (Class I), and forms of pulmonary hypertension associated with left heart disease (Class II), lung disease (Class III), pulmonary artery obstructions including chronic pulmonary embolism (Class IV) or other less common causes (Class V). Patients with PH are at risk in the current COVID 19 pandemic.

The course of the disease and the prognosis of the patients are assessed on the basis of various parameters and therapy is adapted accordingly. In addition to clinical, echocardiographic and laboratory examinations, cardiopulmonary performance tests such as the 6-minute walking distance (6MWD) are of particular significance. According to the ESC/ERS guidelines for PH and the recommendations of the Cologne Consensus Conference, exercise performance is a central criterion for prognostication and treatment decisions.

During the COVID-19 pandemic, hospitals require the constant use of face masks for patients, in most cases also during the 6 minute walking test. We suspect a performance-reducing effect of face masks, thus impacting the results of the 6MWD. A systematic error in the assessment of cardiopulmonary performance should be revealed by comparing the results of the 6MWD with and without mask (particularly surgical mask and FFP2 mask).

Monocentric, prospective, randomized cross-over study in approximately 120 patients with PH (n=60 for surgical face mask versus no mask; n=60 for FFP2 mask vs. no mask) to evaluate the impact of face masks on 6MWD, Borg dyspnea score, and O2 saturation pre- versus post exercise. Patients are randomized to perform the test with vs. without mask first, and then cross over to the respective other condition.

The primary endpoint is the intra-individual difference in 6MWD with and without mask (analyzed for the whole study group, and for surgical mask and FFP2 mask seperately). Secondary endpoints include differences in Borg score, and O2 saturation.

Inclusion Criteria:

• Regular 6MWD in the last 24 months, at least 1 test per 24 months
• Pulmonary (arterial) hypertension according to the Nice Classification Type I-V
• NYHA-WHO/FC I - III
• Lung function test performed within 6 months
• Age ≥18 years
• Severity of symptoms and specific therapy stable during the last 4 weeks
• General ability to participate in the study
• Ability to give consent

Exclusion Criteria:

• Contact allergy to face mask materials
• Significant peripheral arterial occlusive disease (Fontaine ≥ IIb)
• Muscular or orthopedic diseases of the lower extremities that contribute to reduced resilience
• Relevant coronary heart disease (angina pectoris ≥ CCS II or positive stress test, myocardial infarction or bypass surgery within the last 3 months)
• inability to perform the 6-minute walk test (mental, physical) or lack of ability to provide essential information (questionnaire, Borg level)
• Uncontrolled high blood pressure (≥140/90 mmHg or ≥160/100 mmHg with 3 antihypertensive drugs) or resting heart rate ≥ 100 b.p.m.)
• Fresh fractures / broken bones (within the last 3 months)
• Not able to give consent Insufficient ability to walk (NYHA IV, immobility, other ailments)