Stent Retriever Thrombectomy in Patients With Myocardial Infarction The Open-label, Multicenter NATURE Superiority trial.

BACKGROUND: Patients with myocardial infarction and large thrombus burden face greater infarct size and higher mortality, yet no effective therapy exists for this high-risk subgroup. OBJECTIVES: To investigate the effects of stent-retriever thrombectomy in addition to conventional percutaneous coronary intervention (PCI) versus conventional PCI alone on infarct size. METHODS: In this open-label, multicenter, superiority trial, 160 patients with ST-segment elevation myocardial infarction and large thrombus burden at angiography (TIMI thrombus grade ≥3 in infarct-related artery) were consented and 156 randomly assigned to undergo stent-retriever thrombectomy followed by conventional PCI or conventional PCI alone. Primary outcome was infarct size extension assessed by area under the curve (AUC) for creatine kinase (CK)-MB. Safety outcome was major adverse cardiovascular events (MACE; comprising cardiovascular death, nonfatal myocardial infarction, nonfatal stroke), at 3 and 30 days. RESULTS: Infarct size (CK-MB AUC) was lower in the stent-retriever group (n=78) versus the conventional group (n=76) (3965 IU/L·h; interquartile range [IQR] 2480-5092 versus 5250; IQR 3506-7449; difference -1359, 95% CI -2231 to -522; p=0.001). At exploratory cardiac magnetic resonance findings, infarct size was lower in the stent-retriever group (n=64; left ventricle, 17%; IQR 11-28) versus the conventional PCI group (n=59; 28.0%; IQR 18-33; difference -7.0, 95% CI -12 to -2.0), whereas left ventricular volumes and ejection fraction did not differ. There was no MACE at 3 days and 1 at 30 days in the stent-retriever group versus 2 and 3, respectively, in the conventional PCI group. CONCLUSIONS: Stent-retriever thrombectomy followed by conventional PCI in patients with large thrombus burden undergoing primary PCI ≤8 hours of symptom onset was associated with reduced infarct size versus conventional PCI alone.