The neutrophil-lymphocyte ratio (NLR) may serve a potential role as a diagnostic and prognostic marker in acute ischemic stroke (AIS) and may also offer utility in aiding treatment decision making, according to research published in Acta Neurologica Scandinavica.
In the context of AIS, biomarkers can be used to aid prognosis, guide treatment decisions, and predict complications following stroke. Additionally, biomarkers may also be helpful in evaluating the efficacy of secondary prevention protocols. Markers derived from computed tomography perfusion, for instance, may predict clinical outcomes of patients with AIS treated with endovascular thrombectomy.
Currently, NLR is not used as part of standard of care and acute stroke pathways, nor is it recommended in the American Heart Association/American Stroke Association acute stroke guidelines.
Australian researchers recently conducted a literature review to gauge the role of NLR, a potential biomarker, in patients with AIS receiving reperfusion therapy. The study researchers identified some studies and meta-analyses which showed an association between NLR and prognostic outcomes in patients with AIS. However, treatments varied among studies included in the meta-analyses, limiting these findings.
Other meta-analyses found in the literature review showed NLR offered predictive value for patients with AIS treated with reperfusion therapy. The use of NLR was also helpful in previous research for stratifying patients with AIS in the acute critical care setting for cardiac reperfusion. In another study, higher NLR on admission in patients with AIS undergoing revascularization was associated with a higher risk of hemorrhagic transformation and neurologic worsening within a 24-hour period from admission.
While NLR shows promise in the available literature, many of the research studies on NLR in AIS featured small sample sizes. Larger randomized studies may be needed to determine the full extent of NLR in clinical care and to inform clinical guidance.
The review authors suggested characterizing subgroups of patients with AIS “using standardized NLR thresholds may assist in identifying patients who are at an increased risk of poor prognosis following 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