Twelve-month clinical outcomes of acute non-ST versus ST-segment elevation myocardial infarction patients with reduced preprocedural thrombolysis in myocardial infarction flow undergoing percutaneous coronary intervention

Background Reduced preprocedural thrombolysis in myocardial infarction (TIMI) flow in patients with ST-segment elevation myocardial infarction (STEMI) is known to be associated with increased mortality. However, clinical implications of reduced preprocedural TIMI flow in patients with non-ST-segment elevation myocardial infarction (NSTEMI) have not been fully elucidated as yet. The aim of the present study was to compare the clinical influence of reduced preprocedural TIMI flows between patients with STEMI and NSTEMI undergoing percutaneous coronary intervention (PCI). Methods From the Korea Acute Myocardial Infarction Registry, a total of 7336 AMI patients with angiographically confirmed reduced preprocedural TIMI flow (TIMI 0/1) during PCI were selected and divided into STEMI (n=4852) and NSTEMI (n=2484) groups. The 12-month composite of total death, nonfatal myocardial infarction, coronary artery bypass graft, and repeated PCI was compared between the two groups. Results After adjustment of baseline confounders by propensity score stratification, the NSTEMI group had lower incidences of major adverse cardiac events than the STEMI group (7.15 vs. 11.19%; hazard ratio: 0.63; 95% confidence interval: 0.47-0.84; P=0.001) at 12 months, which was largely attributable to the lower incidences of total deaths (2.43 vs. 3.99%; P=0.04) and repeated PCI (3.81 vs. 6.41%; P=0.01). Conclusion Among AMI patients with TIMI 0/1, patients with NSTEMI had better outcomes compared with those of patients with STEMI on the basis of the incidences of 12-month outcomes. This could be attributable to lower total death and repeated revascularization in patients with NSTEMI.