Predicting adverse events with platelet and neutrophil number

The aim of this study was to determine whether the proportion of platelets and neutrophils can be used to predict long-term negative outcomes in patients who have had a percutaneous coronary intervention (PCI, a procedure done to improve blood flow and prevent heart attacks). 

Neutrophils are cells that are involved in inflammation (reaction to injury or infection). Platelets are cells that stop bleeding. Lymphocytes are cells involved in the immune response. The neutrophil-to-lymphocyte ratio has been shown to be potentially able to predict of risk of heart problems.

Studies suggest that the neutrophil-to-lymphocyte ratio is associated with adverse events (undesired effect of treatment). Studies have also shown that platelet-to-lymphocyte ratio can predict adverse outcomes in various heart diseases. It is not well known whether platelet-to-lymphocyte ratio and the neutrophil-to-lymphocyte ratio can be used together to predict the long-term adverse events in coronary artery disease, such as following PCI.

A total of 798 patients were studied. The average follow-up period was 62.8 months. There was a total of 51 adverse events. Examples of adverse events were death from any cause or heart problems, and heart attack.

Patients were classified into four groups based on the platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio. Patients with a high platelet-to-lymphocyte ratio and a high neutrophil-to-lymphocyte ratio were significantly older. They were less likely to smoke and had lower levels of fat (cholesterol).

Patients with a high platelet-to-lymphocyte ratio were 2.4 times more at risk of poor long-term survival and outcome. Patients with high neutrophil-to-lymphocyte ratio were 3 times more at risk of poor long-term survival and outcome. Patients with a combined high platelet-to-lymphocyte ratio and high neutrophil-to-lymphocyte ratio were 4 times more at risk of poor long-term survival and outcome. 

Patients with a combination of a high platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio were 2.7 times more at risk of an adverse event. 

The authors concluded that the platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio, especially when combined, could predict long-term adverse outcomes.