Normal Saline Infusion After Intravenous Thrombolysis in Stroke

Inclusion Criteria: 1. Age 18 to 80 years. 2. Acute ischemic stroke treated with intravenous thrombolysis. 3. Prestroke mordified Rankin Scale score ≤1; 4. Admission NIHSS score 4-25, with NIHSS 4-5 requiring the presence of a disabling deficit as defined in the 2026 AHA/ASA Guideline for the Early Management of Patients With Acute Ischemic Stroke. 5. Onset-to-needle time≤4.5 hours or DWI-FLAIR mismatch (guided by MRI evaluation) for patients with uncertain stroke onset time according to the inclusion criteria of the WAKE-UP study. 6. Signed informed consent. Exclusion Criteria: 1. Contraindications to intravenous thrombolysis. 2. Planned endovascular treatment prior to enrollment. 3. History of heart failure, or pre-enrollment brain natriuretic peptide (BNP) ≥100 pg/mL, or clinical presentations or signs suggestive of heart failure. 4. History of atrial fibrillation, or pre-enrollment electrocardiogram indicating atrial fibrillation. 5. History of valvular heart disease or valve replacement surgery, suggesting cardioembolic stroke. 6. History of renal dysfunction, or pre-enrollment serum creatinine \>133 μmol/L, or estimated glomerular filtration rate (eGFR) \<60 mL/min/1.73 m². 7. Severe hemorrhage prior to enrollment, including symptomatic intracranial hemorrhage, gastrointestinal bleeding, respiratory tract bleeding, or massive skin and mucous membrane bleeding. 8. Premature termination of intravenous thrombolysis due to any reason, such as hemorrhage, allergic reaction, or seizure. 9. Participation in another clinical trial within the previous 3 months. 10. Poor compliance, or inability to adhere to the trial protocol or complete follow-up.