Non-immunogenic Recombinant Staphylokinase vs Placebo in Patients With Intermediate High-risk Pulmonary Embolism

Inclusion Criteria: * Men and women aged 18 and over. * Verified diagnosis of intermediate high-risk PE using CTPA, no more than two weeks from the symptoms onset. * RV dysfunction, defined as a RV/LV ventricular end-diastolic diameter ratio more than 1.0 assessed by CTPA. * Increased risk of early death or hemodynamic collapse, defined by one of the following criteria: 1. systolic blood pressure less than 110 mm Hg, but not less than 90 mm Hg for more than 15 minutes; 2. respiratory rate more than 20 per minute or SpO2 less than 90% without oxygen support; 3. chronic heart failure with left ventricular ejection fraction less than 40%. * Serum troponin I level more than 14 pg/mL in patients under 75 years, and more than 45 pg/mL in patients aged 75 years or older. * Patient consent to use reliable contraceptive methods throughout the study and for 3 weeks after: * women who have a negative pregnancy test and use the following contraceptives: intrauterine devices, oral contraceptives, contraceptive patch, prolonged injectable contraceptives, double barrier method of contraception. Women who are not fertile can also take part in the study (documented conditions: hysterectomy, tubal ligation, infertility, menopause for more than 1 year); * men using barrier contraception. The study may also involve men who are not fertile (documented conditions: vasectomy, infertility). * Availability of signed and dated informed consent of the patient to participate in the study. Exclusion Criteria: * High-risk PE with hemodynamic instability. * Increased risk of bleeding: * extensive bleeding at present or within the previous 6 months; * intracranial (including subarachnoid) hemorrhage at present or in history; * hemorrhagic stroke within the last 6 months; * a history of diseases of the central nervous system (including neoplasms, aneurysms); * intracranial or spinal surgical interventions within the last 2 months; * major surgery or major trauma within the previous 4 weeks; * recent puncture of an incompressible blood vessel (eg, subclavian or jugular vein); * severe liver disease, including liver failure, cirrhosis, portal hypertension (including esophageal varices) and active hepatitis; * confirmed gastric or duodenal ulcer within the last 3 months; * neoplasm with an increased risk of bleeding; * simultaneous administration of Dabigatran without prior administration of idarucizumab; * arterial aneurysms, developmental defects of arteries / veins; * acute pancreatitis; * bacterial endocarditis, pericarditis; * suspicion of aortic dissecting aneurysm; * any other conditions, in the opinion of the investigator, associated with a high risk of bleeding. * Lactation, pregnancy. * Known hypersensitivity to the non-immunogenic recombinant staphylokinase.