Thirty-day mortality in ST-elevation myocardial infarction (STEMI) patients is primarily driven by cardiogenic shock (CS). A high neutrophil count and a high neutrophil/lymphocyte ratio (NLR) have previously been associated with mortality in STEMI patients, however, there is only sparse knowledge on their association with CS.
We sought to assess the associations between neutrophil count and NLR with the development of CS as well as mortality in STEMI patients.
Patients admitted with STEMI at two tertiary heart centers during 2015/2016 were consecutively included in the study and stratified into quartiles according to the level of leucocyte count upon admission. According to the onset of CS, we divided the patients into two groups: 1) early CS, which entailed patients who either presented with CS on admission or developed CS in the catheterization laboratory, and 2) late CS, which entailed patients who developed CS after leaving the catheterization laboratory. The associations between neutrophils and NLR with CS development were assessed by logistic regression models while the associations with death were assessed by cox proportional hazard models. Furthermore, the associations with death were depicted by Kaplan-Meier curves tested by the log-rank test.
A total of 1892 STEMI patients were included. Of these, 194 (10%) patients developed CS while 122 (6.4%) patients died during the first 30 days. Patients in the highest quartile of neutrophil count (OR, 2.54; 95% CI, 1.40-4.60; p = 0.002) and NLR (OR, 3.64; 95% CI, 2.02-6.54; p < 0.0001) had a higher risk of developing late CS when adjusted for clinical signs of peripheral hypoperfusion, heart rate, systolic blood pressure and admission lactate concentration. Furthermore, an increased 30-day mortality rate was seen among patients in the highest quartiles of neutrophils and NLR (Figure, p < 0.0001) and, moreover, a high level of neutrophils was independently associated with 30-day mortality (HR, 1.95; 95% CI, 1.25-3.03; p = 0.003) when adjusted for age, known heart failure, cardiogenic shock, multiple vessel disease, left ventricular ejection fraction and admission lactate concentration.
High levels of neutrophils (> 11.0 x 109/l) and a high NLR (> 6.9) upon admission for STEMI were independently associated with a higher risk of developing late CS. Additionally, both biomarkers were associated to 30-day mortality and may, thus, prove valuable for early risk stratification.