From the Research
Approximately 64.4% of STEMI patients have 100% occlusion of a coronary artery, as indicated by Thrombolysis in Myocardial Infarction (TIMI) flow grade 0. This complete blockage typically occurs when a coronary artery plaque ruptures and a blood clot forms, completely obstructing blood flow to a portion of the heart muscle. The remaining patients may have severe stenosis (narrowing) that is not completely occluded but is still causing significant ischemia, or they may have had spontaneous reperfusion where the clot partially dissolved before cardiac catheterization.
Key Points
- The presence of ST-segment elevation on ECG correlates strongly with complete coronary occlusion, which is why STEMI is considered a medical emergency requiring rapid intervention to restore blood flow and minimize heart muscle damage 1.
- The most common infarct-related arteries (IRAs) were the right coronary artery (RCA) and left circumflex artery (LCx) in the STEMI and NSTEMI groups, respectively 1.
- Totally occluded IRA (TIMI flow grade 0) on baseline angiogram was associated with higher in-hospital mortality in STEMI patients with occlusion of the left anterior descending artery (LAD) or LCx 1.
Clinical Implications
- Complete occlusions require immediate reperfusion therapy, either through primary percutaneous coronary intervention (PCI) or fibrinolytic therapy if PCI is not available within 120 minutes.
- The OMI paradigm shift, based on the presence or absence of acute coronary occlusion (ACO) in the patient rather than STE on ECG, offers the next opportunity to transform emergency cardiology and improve patient care 2.
- Advanced ECG interpretation aided by artificial intelligence, complementary bedside echocardiography and advanced imaging, and clinical signs of refractory ischemia can help identify patients with ACO and guide treatment decisions 2.