Objective: An acute pulmonary embolism is formed sudden obstructions in some pulmonary arterial and thrombus that cause these obstructions comes mostly from deep leg or pelvis veins. Acute pulmonary embolism with incomplete resolution is observed frequently and chronic thromboembolism can result in pulmonary hypertension. Our purpose in this study is to evaluate the frequency and markers of chronic thromboembolism pulmonary hypertension(CTEPH) and the demographic and clinical features of acute pulmonary embolism patients. Material and Methods: Participants were 127 patients hospitalized due to an acute pulmonary embolism diagnosis between 1 January 2014- 30 April 2015. Patients having any kind deficiency in the D-Dimer blood test, arterial blood gas, computed tomography, lower extremity Doppler ultrasonography, echocardiography, clinical scoring (Wells and revised Geneva) were excluded. 45 patients, whose transcriptions were exact, were included in this study. Results: The p02 value is found to be significantly low in submassive patients in comparison with non-massive patients. Values of Geneva scoring were found to be significantly different not only between submassive and massive patients but also between non-massive and massive. Significant difference between non-massive and massive is deteched in the value of D-Dimer. CTEPH was evolved on 10 subjects. Conclusion: Diagnose acute pulmonary embolism with severe morbidity and mortality, then to start treatment accordingly by determining the severity of the disease are extremely important. Also, physicians need to be aware of CTEPH, which is a preventable complication of acute pulmonary embolism, if they are to predict which patients are likely to develop CTEPH.