Impact of acute total occlusion of the culprit artery on outcome in NSTEMI based on the results of a large national registry

BACKGROUND: The impact of acute total occlusion (TO) of the culprit artery in non-ST-segment elevation myocardial infarction (NSTEMI) is not fully established. We aimed to evaluate the clinical and angiographic phenotype and outcome of NSTEMI patients with TO (NSTEMI(TO)) compared to NSTEMI patients without TO (NSTEMI(NTO)) and those with ST-segment elevation and TO (STEMI(TO)). METHODS: Demographic, clinical and procedure-related data of patients with acute myocardial infarction who underwent percutaneous coronary intervention (PCI) between 2014 and 2017 from the Polish National Registry were analysed. RESULTS: We evaluated 131,729 patients: NSTEMI(NTO) (n = 65,206), NSTEMI(TO) (n = 16,209) and STEMI(TO) (n = 50,314). The NSTEMI(TO) group had intermediate results compared to the NSTEMI(NTO) and STEMI(TO) groups regarding mean age (68.78 ± 11.39 vs 65.98 ± 11.61 vs 64.86 ± 12.04 (years), p < 0.0001), Killip class IV on admission (1.69 vs 2.48 vs 5.03 (%), p < 0.0001), cardiac arrest before admission (2.19 vs 3.09 vs 6.02 (%), p < 0.0001) and death during PCI (0.43 vs 0.97 vs 1.76 (%), p < 0.0001)—for NSTEMI(NTO), NSTEMI(TO) and STEMI(TO), respectively. However, we noticed that the NSTEMI(TO) group had the longest time from pain to first medical contact (median 4.0 vs 5.0 vs 2.0 (hours), p < 0.0001) and the lowest frequency of TIMI flow grade 3 after PCI (88.61 vs 83.36 vs 95.57 (%), p < 0.0001) and that the left circumflex artery (LCx) was most often the culprit lesion (14.09 vs 35.86 vs 25.42 (%), p < 0.0001). CONCLUSIONS: The NSTEMI(TO) group clearly differed from the NSTEMI(NTO) group. NSTEMI(TO) appears to be an intermediate condition between NSTEMI(NTO) and STEMI(TO), although NSTEMI(TO) patients have the longest time delay to and the worst result of PCI, which can be explained by the location of the culprit lesion in the LCx.