Predictors of suboptimal coronary blood flow after primary angioplasty and its implications on short-term outcomes in patients with acute anterior STEMI

Background: Suboptimal coronary blood flow after primary percutaneous coronary intervention (PCI) is a complex multifactorial phenomenon. Although extensively studied, defined modifiable risk factors and efficient management strategy are lacking. This study aims to determine the potential causes of suboptimal flow and associated impact on 30-day outcomes in patients presenting with anterior ST-elevation myocardial infarction (STEMI). Methods: We evaluated a total of 1104 consecutive patients admitted to our hospital from January 2016 to December 2018 with the diagnosis of anterior wall STEMI who had primary PCI. Results: Overall, 245 patients (22.2%) had final post-PCI TIMI flow ≤2 in the LAD (suboptimal flow group) and 859 (77.8%) had final TIMI-3 flow (optimal flow group). The independent predictors of suboptimal flow were thrombus burden grade (Odds ratio (OR) 1.848; p < 0.001), age (OR 1.039 per 1-year increase; p < 0.001), low systolic blood pressure (OR 1.017 per 1 mmHg decrease; p < 0.001), total stent length (OR 1.021 per 1 mm increase; p < 0.001), and baseline TIMI flow ≤1 (OR 1.674; p = 0.018). The 30-day rates of major adverse cardiovascular events (MACE) and cardiac mortality were significantly higher in patients with TIMI flow ≤2 compared to those with TIMI-3 flow (MACE: adjusted risk ratio [RR] 2.021; P = 0.025, cardiac mortality: adjusted RR 2.931; P = 0.031). Conclusion: Failure to achieve normal TIMI-3 flow was associated with patient-related (age) and other potentially modifiable risk factors (thrombus burden, admission systolic blood pressure, total stent length, and baseline TIMI flow). The absence of final TIMI-3 flow carried worse short-term clinical outcomes.