Acute pulmonary embolism (PE) is a serious disease associated with high mortality rates despite advanced therapeutic options. The treatment options depend on the severity of the disease and the short - term mortality varies widely from 2 to 95%, depending on the severity of the condition

Acute pulmonary embolism (PE) is a serious disease associated with high mortality rates despite advanced therapeutic options. The treatment options depend on the severity of the disease and the short - term mortality varies widely from 2 to 95%, depending on the severity of the condition.

Initial risk stratification of patients with PE could be based on clinical indicators. The presence of shock and hypotension is the most important clinical sign of poor prognosis. Other clinical variables, associated with poor prognosis are age over 70 years, history of bed rest over five days, cancer, chronic obstructive pulmonary disease, renal failure, heart failure, and tachycardia .

Echocardiography represents the most useful imaging tool in everyday clinical practice to show right ventricular dysfunction (RVD) because of its noninvasive nature and relative low cost. RVD assessed on echocardiography has been described as one of the strongest predictor of early mortality in PE .

Currently, computed tomography pulmonary angiography (CTPA) represents the diagnostic gold standard for PE. Additionally, CTPA was used to evaluate the prognosis by determining the distribution and severity of vascular obstruction of clots in pulmonary circulation; this is called computed tomography pulmonary artery obstruction index (CT-PAOI). CTPA was also suggested as a predictor of RVD .

In addition to the clinical findings and the imaging abnormalities, there are several biomarkers and indicators that can be used to predict severity and prognosis in patients with PE. These biomarkers include troponin and brain natriuretic peptide (indicators of RVD and myocardial damage), D-dimer, C-reactive protein, arterial blood gases parameters and complete blood count (CBC) parameters. However, some of these biomarkers have not been widely studied and are not commonly used although they are readily available and cheaper for developing countries.

Inclusion Criteria:

• Adults (≥ 18 years) who will be diagnosed as acute pulmonary embolism based on computed tomography pulmonary angiography (CTPA) and not yet treated.

Exclusion Criteria:

1. Age less than 18 years.
2. Patients with known hematological disorders.
3. Patients with history of recent blood transfusion (within 3 weeks).
4. Patients receive anti-platelet and/or anticoagulant medications.
5. Patients receive immunosuppressive drugs.
6. Patients with known cardiopulmonary diseases other than the pulmonary embolism.
7. Patients with known active infectious diseases or immunological diseases

patients admitted at the Chest Department and Respiratory Intensive Care Unit (RICU) at Assiut University Hospital.