The target population of this interventional study was STEMI patients. Primary discussion: Early rhBNP reduces microcirculation obstruction in STEMI patients undergoing primary PCI

Direct percutaneous coronary intervention is the preferred reperfusion strategy for acute ST-segment elevation myocardial infarction. During the opening of infarct-related vessels, 5%-50% of patients showed slow flow or no reflow and other coronary microcirculation dysfunction, which aggravated myocardial injury and increased the incidence and mortality of heart failure. Studies have shown that recombinant human brain natriuretic peptide (rhBNP) can reduce reperfusion injury and reduce myocardial infarction area CMD. Prolonged ischemia leads to rapid depletion of intracellular ATP and tissue metabolic acidosis. Blood flow irrigation during reperfusion leads to decreased levels of ATP precursors, calcium overload in mitochondria, release of a large number of inflammatory factors and oxygen free radicals, which can lead to injury or death of myocardial and endothelial cells. rhBNP can enhance the activity of antioxidant enzymes, reduce the irreversible oxidative damage caused by free radicals to myocardium, reduce the myocardial infarction area during ischemia reperfusion, and may reduce the reperfusion injury and protect the viable myocardium.

Inclusion Criteria:

• STEMI
• PPCI within 24 hours of symptom onset
• Target vessel QFR-MR>250mm Hg*s/m

Exclusion Criteria:

• claustrophobia
• Postoperative TIMI grade 0-1
• Pregnancy