Heart attack patients to receive injectable gel that may limit damage

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Aged 18 to 80 years; 2. Diagnosed with first-onset acute anterior wall ST-segment elevation myocardial infarction (STEMI), requiring primary percutaneous coronary intervention (PCI) and stent implantation; 3. Ischemic symptoms (e.g., chest pain, precordial discomfort) persist for \>30 minutes, and electrocardiographic findings meet the following criteria: ST-segment (J-point) elevation ≥1.0 mm (i.e., amplitude 0.1 mV) in all conventional leads except leads V2 and V3. For leads V2 and V3, the ST-segment elevation criteria are: ≥2.5 mm in males \<40 years old, ≥2.0 mm in males ≥40 years old, and ≥1.5 mm in females of all ages; 4. The time interval from the onset of ischemic symptoms to the first PCI balloon dilation is ≤12 hours; 5. Admission coronary angiography shows that the left anterior descending artery (LAD) has a TIMI flow grade of 0 (complete occlusion), and the TIMI flow grade reaches 3 after stent implantation; 6. Able to understand the purpose of the trial, voluntarily participate in the study, sign the informed consent form personally or via a legal representative, and be willing to complete the follow-up in accordance with the protocol requirements. Exclusion Criteria: 1. Complicated with cardiogenic shock or cardiac arrest; or complicated with acute myocardial infarction mechanical complications requiring surgical or interventional intervention (e.g., ventricular septal perforation, papillary muscle rupture, free wall rupture), or complicated with giant left ventricular aneurysm; 2. Previously diagnosed with hypertrophic cardiomyopathy, hemodynamically significant congenital heart disease, severe valvular heart disease, chronic cor pulmonale, chronic heart failure, or with a history of cardiac tamponade, pericarditis, or myocarditis; 3. History of previous myocardial infarction, coronary intervention (PCI), or coronary artery bypass grafting (CABG); 4. Cerebrovascular accident (CVA) or transient ischemic attack (TIA) within the past 3 months; 5. Heart failure severity at admission reaches Killip classification Grade III or above; 6. Complicated with malignant arrhythmia, complete atrioventricular block, or new-onset complete left bundle branch block (LBBB); 7. Diagnosed or suspected aortic dissection; 8. Diabetes mellitus with severe complications; 9. Complicated with atrial fibrillation and receiving only warfarin treatment, or with a high bleeding risk; 10. Received thrombolytic therapy prior to PCI; 11. Diameter of the infarct-related artery \< 2 mm or abundant coronary collateral circulation in the risk area; 12. Coronary angiography indicates diffuse vascular lesions or severe calcification that may affect the absorption of protein alginate-based hydrogel; 13. Severe complications (e.g., coronary artery rupture, perforation, or stent dislodgement) occurring during PCI; 14. Received coronary bioresorbable stent implantation; 15. Complicated with severe acute infection requiring systemic treatment; 16. Currently diagnosed with malignant tumor or receiving malignant tumor treatment; 17. Severe autoimmune disease requiring therapeutic intervention; 18. History of severe anemia (hemoglobin \< 60 g/L) or thrombocytopenia (platelet count \< 100×10⁹/L); 19. Known renal insufficiency (including estimated creatinine clearance \< 30 ml/min/1.73 m², or receiving treatment for severe renal insufficiency); 20. Alanine aminotransferase (ALT) level exceeding 3 times the upper limit of normal, with the investigator judging clinically significant liver dysfunction; 21. Known allergy to the study product or any radiocontrast agent; 22. Contraindications to cardiovascular magnetic resonance (CMR) examination (e.g., implanted cardiac pacemaker, implantable cardioverter-defibrillator, nerve stimulator, cerebral aneurysm clip, cochlear implant, or claustrophobia); 23. Cognitive dysfunction, dementia, or severe mental illness; 24. Currently participating in other clinical trials and have not yet reached the primary endpoint; 25. Expected survival period \< 1 year due to comorbidities; 26. Pregnant or lactating women, or fertile subjects who do not take effective medical contraceptive measures during the study period; 27. Other factors that the investigator deems may have a significant impact on result judgment or the safety and efficacy of the subjects.