Neutrophil-to-lymphocyte ratio (NLR) could play a potential role as a diagnostic and prognostic marker in acute ischemic stroke (AIS) and also be useful in treatment decision-making, according to a study published in Acta Neurologica Scandinavica.
In the context of AIS, biomarkers can be used to aid prognosis, make treatment decisions, and predict complications after a stroke. In addition, biomarkers can also be helpful in evaluating the effectiveness of secondary prevention protocols. For example, markers derived from computed tomography perfusion can predict clinical outcomes in patients with AIS who have been treated with endovascular thrombectomy.
Currently, NLR is not used as part of standard care and treatment pathways for acute stroke, nor is it recommended in the American Heart Association / American Stroke Association guidelines for acute stroke.
Australian researchers recently conducted a literature review to assess the role of NLR, a potential biomarker, in patients with AIS receiving reperfusion therapy. Study researchers identified several studies and meta-analyzes that showed an association between NLR and prognostic outcomes in patients with AIS. However, the treatments varied between the studies included in the meta-analyzes, which limited these results.
Other meta-analyzes found in the literature review showed that NLR provides predictive value for patients with AIS who are treated with reperfusion therapy. The use of NLR has also been helpful in previous research stratifying patients with AIS in acute critical care for cardiac reperfusion. In another study, a higher NLR at admission in patients with AIS undergoing revascularization was associated with a higher risk of hemorrhagic transformation and neurological deterioration within 24 hours of admission.
While NLR shows promise in the available literature, many of the research studies on NLR in AIS showed small sample sizes. Larger randomized trials may be needed to determine the full extent of NLR in clinical care and to inform clinical guidance.
The review authors suggested characterizing subsets of patients with AIS “who, using standardized NLR thresholds, can help identify patients who are at increased risk of poor prognosis after reperfusion therapy”.
Sharma D, Spring KJ, Bhaskar SMM. Neutrophil-lymphocyte ratio in acute ischemic stroke: immunopathology, management, and prognosis. Published online June 30, 2021. Acta Neurol Scand. doi: 10.1111 / ane.13493