Do not be fooled by appearances when N-STEMI is a TIMI 0-1 blood grade flow: Definition, prevalence, and predictive factors of total occlusion-NSTEMI

BACKGROUND: Owing to chest pain units, rates of cardiovascular mortality due to acute coronary syndrome have decreased. However, some patients present as ACS without ST-segment elevation but with total arterial occlusion on invasive coronary angiography. This study aimed to identify the prevalence of total occlusion-NSTEMI and identify predictive factors compared to other true NSTEMI for early treatment.

METHODS: This observational retrospective study analyzed 9552 patients admitted to the cardiac emergency room of Poitiers University Hospital between January 2014 and June 2016: among them, 1603 presented for chest pain with cardiac troponin elevation. Fifty-two patients were identified as having TO-NSTEMI. The circumflex artery was the most frequently occluded coronary artery (58%).

RESULTS: Multivariate analysis demonstrated that the first troponin dose was already much higher for the TO-NSTEMI group than for the NSTEMI group (P < 0.001) and that the Global Registry of Acute Coronary Events (GRACE) score was lower in the TO-NSTEMI group (P=0.01). The probability of TO-NSTEMI occurrence was significantly greater in patients with a first troponin dose >0.152 μg/L (sensitivity, 67%; specificity, 67%).

CONCLUSION: TO-NSTEMI, representing 3.2% of our acute coronary syndrome population, is not a rare diagnosis. These patients have no specific characteristics compared to NSTEMI. GRACE score does not seem predictive at all. A first troponin dose greater than ten times the normal dose must make us suspect the diagnosis. According to our study, any persistent chest pain, although slight, with abnormal ECG findings, should be considered as STEMI requiring immediate coronary angiography.