The relationship between clinical outcomes and calculation of thrombus burden before or after initial flow in patients with ST segment elevation myocardial infarction

Introduction: Primary percutaneous coronary intervention (PPCI), is the standard treatment in patients with STEMI. Although myocardial and epicardial perfusion is usually achieved with PPCI, infarct-related arterial (IRA) thrombus burden negatively affects procedural success and clinical outcomes. In our study, we investigated the relationship between thrombus burden in patients with STEMI before and after initial flow, and clinical outcomes. Method: We retrospectively enrolled 1376 patients with STEMI between May 2012 - November 2015. Patients who underwent only balloon angioplasty and would go to emergency coronary artery bypass graft (CABG) surgery were not included in the study. Initial clinical and demographic characteristics of the patients were obtained from hospital records. Thrombus burden were calculated using the TIMI thrombus score, baseline and final (after wire inflation or small balloon dilatation). The endpoints of our study were defined as no-reflow development after PPCI and death due to all causes at 1-year follow-up. Statistical significance was defined as <0.05 for p value. Results: After the post-procedural records of the patients were examined, no-reflow was detected in 169 patients (12,3%). It was determined that the calculated basal thrombus burden was associated with post-procedural no-reflow (p< 0.001). It was also associated with no-reflow in older age (p< 0.001), longer pain to door time (p< 0.001) and increased blood glucose level (p: 0.032). The calculated final thrombus burden was found to be related to 1-year all-cause mortality (p: 0.047). It was also associated with 1-year all-cause death in older age (p< 0.001), high Killip scores (p: 0,003), increased white blood cell (p: 0.001) and low estimated glomerular filtration rate (p< 0.001). Conclusion: In our study, we found that basal thrombus burden was associated with no-reflow and final thrombus burden was associated with 1-year all-cause mortality. That is, we think that the calculation of the thrombus burden before or after the initial flow of current has different effects on the clinical outcomes. Key words: Myocardial infarction, thrombus burden, no-reflow