Inclusion Criteria:  Patients over 18 years old. Patients diagnosed with polycythemia vera, essential thrombocythemia, primary myelofibrosis and chronic myeloid leukemia according to the 2016 WHO classification and attended the outpatient Hematology Clinic at Sohag University Hospital.  Exclusion Criteria:  Patients less than 18 years old. Patients with pre-existing pulmonary hypertension from any other cause. Patients with left sided heart disease e.g. left sided heart failure, left sided valvular diseases, cardiomyopathies, left ventricular systolic or diastolic dysfunction. Patients with chronic lung disease e.g. COPD & interstitial lung disease. Patients with chronic kidney disease. Patients with connective tissue diseases. Patients with congenital heart diseases.