The study aims to explore the efficacy and safety of erythrocytapheresis in chronic mountain sickness

This study aims to evaluate the efficacy and safety of erythrocytapheresis in patients with Chronic Mountain Sickness (CMS). Residents of high-altitude regions diagnosed with CMS will be enrolled and randomly allocated into two groups. The control group will receive standard of care, including supplemental oxygen and medical management. The intervention group will receive erythrocytapheresis in addition to standard of care. Clinical outcomes, including CMS scores, the Incremental Shuttle Walk Test (ISWT), and relevant hematological and hemodynamic indicators, will be assessed and compared between the two groups to determine the therapeutic benefit of erythrocytapheresis as a hematocrit-reduction strategy.

Inclusion:

1. Age ≥18 years;
2. High-altitude residents or long-term dwellers (continuous residence at ≥2500 meters above sea level for at least 1 year), with no travel history to low-altitude areas in the past 3 months;
3. Hemoglobin (Hb): Men: ≥210 g/L, Women: ≥190 g/L; at least one symptom or sign: headache, dizziness, dyspnea, palpitations, sleep disturbances, fatigue, localized cyanosis, burning sensation in palms/soles, venous dilatation, muscle/joint pain, loss of appetite, poor concentration, or memory changes; CMS total score ≥6;
4. Written informed consent obtained from patients or their legal representatives.

Exclusion:

1. Hematocrit < 60%;
2. Patients with erythrocytosis attributable to: polycythemia vera; secondary erythrocytosis due to dehydration, cyanotic congenital heart disease, or chronic obstructive pulmonary disease; or other underlying hematologic or oncologic conditions;
3. Patients with active pneumonia, pulmonary embolism, or severe organ dysfunction (including cardiac, hepatic, or renal failure);
4. Patients with contraindications to study procedures (including erythrocytapheresis, pulmonary function tests, or incremental shuttle walk test), such as impaired consciousness, pneumothorax, severe arrhythmia, or significant coagulation disorders;
5. Patients who have received CMS-specific interventions within the last 6 months, including phlebotomy, erythrocytapheresis, or targeted pharmacotherapy;
6. Patients currently pregnant, breastfeeding, or planning to become pregnant within 1 year;
7. Any terminal condition with an estimated life expectancy of < 6 months;
8. Current participation in other clinical trials.