Backgrounds and Objective: Acute pulmonary thromboembolism (APTE) is known to have higher mortality rate than acute myocardial infarction. We sought to evaluate clinical outcome of APTE according to the initial presentation, treatment mordalities and underlying diseases through the 10-year clinical observation. Methods: APTE was diagnosed by clinical history, CT angio or perfusion scan, Echocardiography and D-dimer. 181 consecutive patients (male 41%, mean 62-yr) were finally included. Massive APTE was defined as initial systolic BP < 90 mmHg or presented as a shock. Results : Among 181 patients with APTE, 48 (26.5%) had massive APTE and 133 (73.5%) had non-massive APTE. There was no significant differences in age, gender, risk factors, anticoagulation, D-idimer, and BNP between massive and non-massive APTE. But initial systolic and diastolic BP, heart rate were significantly different between two groups. Mortality rate of all patients were 23.8%. Patients with massive APTE had higher mortality rate than non-massive APTE (75% vs 5.3%, p=0.0001). During the follow-up, probability of survival in massive APTE was significantly lower than non-massive PTE (Figure). In patients with massive APTE, surgical embolectomy was performed in 4 patients, thrombolysis in 5, and IVC filter in 8. But any of these procedures did not improve the survival (Figure). Conclusions : Patients with massive APTE had very high mortality rate. Surgical embolectomy, thrombolysis or IVC filter could not improve the survival of massive APTE.