All patients are newly diagnosed Obstructive Sleep Apnea patients performing full night polysmnographic sleep study, whose echocardiographic findings elucidate presence of pulmonary hypertension(PH). These patients seemed to have PH if mPAP ≥25 mmHg . All studied patients were received CPAP therapy with average cumulative adherence ⩾4 h/day of >70% nights [380] obtained from device download with AHI<5 /hr

Echocardiography:

It was performed initially to diagnose pulmonary hypertension and repeated after three months of CPAP therapy as a follow up . All enrolled patients were subjected to trans-thoracic echocardiography using Ultrasound system (Vivid I, GE Healthcare, Little Chalfont, UK), with a 2.5 MHz transducer. Certain measurements were then used to calculate mPAP.

Patients were considered to have PH if mPAP ≥25 mmHg, and were classified into mild (20-40 mmHg), moderate (41-55 mmHg), and severe (>55 mmHg) degrees.

Evidence of PH is found by Doppler echocardiography showing an elevated right ventricular systolic pressure (RVSP).

Inclusion Criteria:

All patients are newly diagnosed Obstructive Sleep Apnea patients performing full night polysmnographic sleep study, whose echocardiographic findings elucidate presence of pulmonary hypertension(PH).

Exclusion Criteria:

• Patients aged < 18 years
• Patients with secondary PH, due to pulmonary diseases, or left ventricular heart diseases , or chronic thromboembolic disorders.
• Patients on long term oxygen therapy (LTOT).
• Patients with respiratory neuromuscular weaknesses or chest wall deformities.
• End-organ failure and malignancies
• Obesity hypoventilation syndrome.