As a multicenter prospective single-arm clinical study, the investigators plan to recruit patients with acute pulmonary intravascular embolization from nationwide multi-center hospital organizations in China. The investigators use the production of transcatheter pulmonary artery bolt system which named 'TwiFlow Thrombectomy Catheter System' developed by the MorningSide (NanTong) medical device Co., LTD. on pulmonary artery interventional therapy to evaluating the efficacy and safety of this novel system in the treatment of patients with pulmonary intravascular embolization disease.

As a multicenter prospective single-arm clinical study, the investigators plan to evaluate the new production's efficacy and safety which named 'TwiFlow-Thrombectomy Catheter System'. This study will be carried out in nationwide multi-center hospital organizations in China. According to the statistical principle, the sample size of this study was estimated, and the final number of selected cases was 127. After screening, all subjects will be treated with transcatheter pulmonary artery thrombectomy system, and clinical follow-up will be conducted at 48 hours, 14 days and 30 days after surgery. Right Ventricular/Left Ventricular decline from baseline to 48 hours after surgery and the incidence of major adverse events (MAE) within 48 hours after surgery were used as primary endpoints. In instrument performance evaluation, the success rate of surgery, postoperative immediate target lesion embolus removal efficiency, pulmonary artery pressure changes before and after operation value, values of arterial oxygen partial pressure changes before and 14 days after operation, death rates related to the equipment in 48 hours after surgery, incident rate of bleeding in 48 hours after operation, postoperative clinical deterioration rate in 48 hours after surgery, postoperative pulmonary vascular injury incidence in 48 hours after surgery, the incidence of heart damage injury in 48 hours after surgery, all-cause death rate in 30 days after surgery, and symptomatic Pulmonary Embolization recurrence rate in 30 days after surgery were secondary endpoints.

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. Duration of pulmonary embolism symptoms ≤14 days
5. Systolic blood pressure ≥90mmHg
6. Patients who agreed to participate in the study and voluntarily signed the informed consent.

Exclusion Criteria:

1. Target vessel diameter < 6.6mm;
2. Calcification, plaque or stenosis of target lesions;
3. Pulmonary arterial hypertension with peak pulmonary arterial pressure >70mmHg;
4. Vasopressor is required after infusion to maintain pressure ≥90mmHg;
5. Hematocrit < 28%;
6. Patients with left bundle branch block;
7. A history of chronic left heart failure and left ventricular ejection fraction≤30%;
8. Patients with abnormal renal function (serum creatinine > 1.8 mg/dL or >159umol/L);
9. Patients with known coagulopathy or bleeding tendency (platelet<100×109/L, or INR> 3);
10. Patients who cannot receive antiplatelet or anticoagulant therapy;
11. Patients who underwent cardiovascular or pulmonary open surgery within 7 days before surgery;
12. Patients with intracardiac thrombosis;
13. Patients treated with extracorporeal membrane oxygenation;
14. Patients known to be allergic to contrast agents;
15. Patients with diseases that may cause difficulty in treatment and evaluation (such as malignant tumor, acute infectious disease, sepsis, general condition that cannot tolerate surgery, life expectancy less than 3 months, etc.);
16. Pregnant and lactating women;
17. Patients who are participating in clinical trials of other drugs or medical devices;
18. Other patients deemed unsuitable for the study by the investigator;