Comparison of Etamsylate Versus Placebo to Prevent Bleeding in HSCT

Inclusion Criteria: 1. Age between 18 and 70 years (inclusive), regardless of gender; 2. Patients diagnosed with a hematological disease requiring hematopoietic stem cell transplantation; 3. Expected platelet count ≤ 10 x 10⁹/L persisting for 5 days or more; 4. Normal coagulation function; 5. Adequate organ function: Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT) ≤ 3 times the Upper Limit of Normal (ULN), Total Bilirubin ≤ 2 x ULN; Serum Creatinine ≤ 2 x ULN; Creatinine Clearance ≥ 50 mL/min (calculated using the Cockcroft-Gault formula); Left Ventricular Ejection Fraction (LVEF) ≥ 50% as measured by Echocardiography (ECHO); 6. Voluntary provision of signed informed consent, with the ability to understand and comply with all study requirements. Exclusion Criteria: 1. Diagnosis of acute promyelocytic leukemia confirmed according to WHO diagnostic criteria; 2. Pregnant or breastfeeding women, and women of childbearing potential unwilling to use effective contraception; 3. Presence of active bleeding or infection; 4. History of diagnosed primary immune thrombocytopenia or hemolytic uremic syndrome; 5. Patients with known hereditary or acquired hemorrhagic disorders; 6. Patients receiving anticoagulant or antiplatelet therapy; 7. Patients with severe cardiac insufficiency (left ventricular ejection fraction \[EF\] \< 60%); or severe arrhythmias: history of clinically significant QTc prolongation (male \> 450 ms; female \> 470 ms), ventricular tachycardia, atrial fibrillation, second-degree heart block; myocardial infarction within 1 year prior to enrollment; or symptomatic coronary artery disease requiring medication; patients with severe liver impairment (liver function indices \[ALT, TBIL\] \> 3 times the upper limit of normal \[ULN\]); 8. Patients with severe pulmonary insufficiency (obstructive and/or restrictive ventilatory defects); 9. Patients with severe renal insufficiency (renal function index \[Cr\] \> 2 times ULN); or 24-hour urinary creatinine clearance rate (Ccr) \< 50 ml/min; 10. Patients with mental disorders or other conditions preventing provision of informed consent and compliance with study treatment and procedural requirements; 11. Other reasons deemed by the investigator to make the patient ineligible for inclusion.