Treatment of acute ischemic stroke is all about timing, but one count could put a halt to treatment with tissue plasminogen activator (tPA).
Illaria Maestrini, MD, of the University of Lille in France, and colleagues examined the effects of high neutrophil count on the risk of intracerebral hemorrhage and post-stroke modified Rankin Scale score at three months in stroke patients treated with tPA.
Prior to tPA administration, blood samples for leukocyte, neutrophil, and lymphocyte counts were collected from 846 patients (median age 71 years; 50.8% men). Both neutrophil count and neutrophil to lymphocyte ratio (NLR) were independently associated with the studies’ four endpoints: symptomatic intracereral hemorrhage (sICH) (adjusted odds ratio [adjOR] for an increase of 1,000 neutrophils = 1.21 and adjOR 1.11, respectively), death (adjOR 1.16 and adjOR 1.08), and excellent (adjOR 0.87 and adjOR 0.85) and good (adjOR 0.86 and adjOR 0.91) outcomes at three months. Total leukocyte count was not found to be associated with any of the endpoints.
The best discriminating factor for sICH was NLR ≥ 4.80 (sensitivity 66.7%, specificity 71.3%, likelihood ratio 2.32). Researchers found that patients with an NLR ≥ 4.80 had a 3.71-fold greater risk for sICH (95% confidence interval adjOR: 1.97–6.98) compared to patients with an NLR < 4.80.
The findings indicate that neutrophil count could potentially be a simple biomarker for patients at greater risk of intracerebral hemorrhage. Previous studies also associated neutrophil count with short- and long-term stroke outcomes, however those studies had noted limitations.
Recognizing how this could potentially effect clinical practice, the researchers said the results would need to be replicated in an independent cohort of patients to better understand the mechanism and determine its value.
“Even if they are confirmed, we cannot recommend the use of NLR in routine practice for the selection of patients to be treated with recombinant tPA, because it will increase delays in all patients, for a not yet proven benefit in a few of them,” they wrote.