Neutrophil/Lymphocyte Ratio as a Predictor of In-Hospital Major Adverse Cardiac Events, New-Onset Atrial Fibrillation, and No-Reflow Phenomenon in Patients with ST Elevation Myocardial Infarction.

Background: Neutrophil/lymphocyte (N/L) ratio represents the balance between neutrophil and lymphocyte counts in the body and can be utilized as an index for systemic inflammatory status. The no-reflow phenomenon is defined as inadequate myocardial perfusion through a given segment of the coronary circulation without angiographic evidence of mechanical vessel obstruction. Systemic inflammatory status has been associated with new-onset atrial fibrillation (NOAF) as well as no-reflow.

Aim: To evaluate the predictive value of N/L ratio for in-hospital major adverse events, NOAF, and no-reflow in patients with ST elevation myocardial infarction (STEMI).

Patients: Two hundred consecutive patients with STEMI presenting to Alexandria Main University Hospital and International Cardiac Center Hospital, Alexandria, Egypt, from April 2013 to October 2013 were included in this study.

Methods: Laboratory investigation upon admission included complete blood count with mean platelet volume (MPV) and N/L ratio, and random plasma glucose (RPG) level. The results of coronary angiography indicating the infarct-related artery (IRA), initial thrombolysis in myocardial infarction (TIMI) flow in the IRA, and the TIMI flow after stenting were recorded. The patients were studied according to the presence of various clinical and laboratory variables, such as age, gender, pain-to-balloon time, location of the infarction, RPG level and complete blood count including N/L ratio and MPV on admission, and initial TIMI flow in the IRA. They were also evaluated for the final TIMI flow after the primary percutaneous coronary intervention, incidence of NOAF, and the incidence of in-hospital major adverse cardiac events (MACE).

Results: The incidence rate of no-reflow, NOAF, and in-hospital MACE was 13.2%, 8%, and 5%, respectively, with cardiac death as the predominant form of in-hospital MACE. The group of no-reflow, NOAF, and/or MACE showed significantly older age (62.29 ± 7.90 vs 56.30 ± 10.34, P = 0.014), longer pain-to-balloon time (15.90 ± 7.87 vs 6.08 ± 3.82 hours, P < 0.001), higher levels of RPG, N/L ratio (8.19 ± 3.05 vs 5.44 ± 3.53, P, 0.001), and MPV (11.90 ± 2.09 vs 8.58 ± 1.84 fL, P < 0.001) on admission. After adjustment of confounding factors, the independent predictors of NOAF, no-reflow, and in-hospital MACE were higher N/L ratio (odds ratio [OR] = 3.5, P = 0.02) and older age (OR = 3.1, P = 0.04).

Conclusions: Older patient age, longer pain-to-balloon time, hyperglycemia, higher N/L ratio, and MPV on admission are useful predictive factors for the occurrence of no-reflow postprimary percutaneous coronary intervention, NOAF, and/or in-hospital MACE. N/L ratio is a new strong independent predictor of no-reflow, NOAF, and/or in-hospital MACE in patients with STEMI. The use of this simple routine biomarker may have a potential therapeutic implication in preventing NOAF and improving prognosis in STEMI revascularized patients.