Incidence and impact of totally occluded culprit coronary artery in patients with non-ST segment elevation myocardial infarction acute coronary syndrome

Background: Significance of totally occluded culprit coronary artery in patients presenting with non-ST segment elevation myocardial infarction (NSTEMI) is underestimated. The aim of the study was to evaluate the incidence and impact of totally occluded culprit artery on in-hospital and 6 months follow-up outcomes of NSTEMI acute coronary syndrome (ACS) patients. Results: We collected retrospectively data of 500 NSTEMI patients who presented to our hospital from June 2016 to June 2017. All patients underwent PCI within 72 h of presentation. We excluded patients with cardiogenic shock, prior CABG, and STEMI. Patients were divided into two groups according to pre-procedural culprit vessel thrombolysis in myocardial infarction (TIMI) flow. Group 1, TIMI flow 0 total coronary occlusion, included 112 patients (22.4%). Group 2, TIMI flow 1-3 non-total occlusion, included 388 patients (77.6%). Group 1 patients had significantly higher incidence of smoking (p=0.01), significantly higher level of cardiac enzymes (p<0.001), significantly more collaterals (p<0.001), and significantly more LCX and RCA as the culprit vessel (p<0.01), while group 2 patients had significantly higher incidence of diabetes (p=0.02) and significantly more LAD as the culprit vessel. There were no significant differences between the two groups regarding the major adverse cardiac and cerebrovascular events (MACCE) in-hospital (5.3% in totally occluded group vs. 1% in non-totally occluded group, p=0.07), but group 1 patients had significantly higher incidence of in-hospital arrhythmia (8.9% in group 1 vs. 1% in group 2, p=0.007). After 6 months follow-up, there were no significant differences regarding MACCE between the 2 groups after 6 months follow-up (5.4% in group 1 vs. 4.6% of group 2, P=0.24). Conclusion: 22.4% of NSTEMI patients have a totally occluded culprit artery. The presence of an occluded culprit artery did not significantly affect the clinical outcomes of NSTEMI patients either in-hospital or after 6 months follow-up but was associated with significantly higher incidence of in-hospital arrhythmia.