Stent-Retriever for Acute Massive Pulmonary Embolism (SRAME)

Inclusion Criteria: \- 1.18≤ age ≤75, no gender limitation; 2.patients clinically diagnosed as acute pulmonary embolism requiring pulmonary artery thrombosis clearance; 3.RV/LV ratio ≥0.9; 4.Patients who agreed to participate in the study and voluntarily signed the informed consent. Exclusion Criteria: 1. Patients with systolic blood pressure\<90 mmHg and lasting for 15 minutes or requiring maintenance of systolic blood pressure ≥ 90 mmHg; 2. Patients with known severe pulmonary hypertension; 3. Patients with Hematocrit \<28%; 4. Patients with known structural heart disease; 5. Patients with left bundle branch block; 6. Patients with history of chronic left heart failure and left ventricular ejection fraction ≤30%; 7. Patients with abnormal renal function (serum creatinine \> 1.8 mg/dL or \>159 umol/L); 8. Patients with known coagulopathy or bleeding tendency (platelet \<100×109/L, or INR\> 3); 9. Patients who cannot receive antiplatelet or anticoagulant therapy; 10. Patients who underwent cardiovascular or pulmonary open surgery within 7 days before peocedure; 11. Patients with intracardiac thrombosis; 12. Patients treated with extracorporeal membrane oxygenation; 13. Patients known to be allergic to contrast agents; 14. Patients with diseases that may cause difficulty in treatment or evaluation (such as malignant tumor, acute infectious disease, sepsis, general condition that cannot tolerate procedure, life expectancy less than one year, etc.); 15. Females who are pregnant or in lactation; 16. Patient is currently enrolled in another investigational study protocol; 17. Other conditions not suitable for inclusion judged by the researcher.