The neutrophil to lymphocyte ratio was associated with impaired myocardial perfusion and long term adverse outcome in patients with ST-elevated myocardial infarction undergoing primary coronary intervention.

Objectives: In the present study we aimed to reveal any probable correlation between neutrophil-to-lymphocyte ratio (N/L ratio) and the occurrence of no-reflow, along with assessment of the prognostic value of N/L ratio in patients with ST-segment elevation myocardial infarction (STEMI).

Background: The N/L ratio stands practically for the balance between neutrophil and lymphocyte counts in the body, which can also be utilized as an index for systemic inflammatory status.

Methods: In our study, we included 204 consecutive patients suffering from STEMI who underwent primary percutaneous coronary intervention (PCI). Patients with STEMI were assigned into distinct tertiles based on their N/L ratios on admission. No-reflow encountered following PCI was evaluated through both angiography [Thrombolysis in Myocardial Infarction (TIMI) flow and myocardial blush grade (MBG)] and electrocardiography (as ST-segment resolution).

Results: Patients featured with no ST-resolution were documented to have displayed significantly higher N/L ratio on admission compared to those with intermediate or complete ST-segment resolution. The number of the patients characterized with no-reflow, evident both angiographically (TIMI flow ≤ 2 or TIMI flow 3 with final myocardial bush grade ≤ 2 after PCI) and electrocardiographically (ST-resolution <30%), was encountered to depict increments throughout successive N/L ratio tertiles. Moreover, the same also held true for three-year mortality rates across the tertile groups (9% vs. 15% vs. 35%, p < 0.01). Multivariable logistic regression analysis disclosed that N/L ratio on admission stood for a significant indicator for long-term mortality in patients with no-reflow phenomenon detected with MBG. Elevated N/L ratio on admission was also found to be a significant indicator for three-year mortality and major adverse cardiac events.

Conclusions: In patients with STEMI who underwent primary PCI, elevated N/L ratios on admission were revealed to be correlated with both no-reflow phenomenon and long-term prognosis.