To the Editor:
We read with great interest the article by Fawaz Al-Mufti et al1 in your journal regarding the prediction of delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage (aSAH). The results from the study suggested that white blood cell (WBC) count is a marker for prediction of DCI in aSAH patients. The authors found that WBC count >12.1 × 109/L within 72 h of admission was predictor of DCI in good-grade (WFNS grade <3) aSAH patients. And WBC count in the first 72 h of admission was stronger than modified-Fisher score.
This article has great clinical significance, providing a trouble-free way to predict DCI following aSAH. We simply need to evaluate WBC count to predict the DCI after aSAH and determine whether the patients should be downgraded from the intensive care unit, which is cost-saving both for patients and hospitals. However, some issues still need to be discussed.
This is a single center observational cohort study, and the value of WBC count in predicting DCI following aSAH should be verified in multi-center prospective controlled trials to give more supporting evidence for its routine clinical use. In addition, the authors found that WBC count is a good predictor in good-grade aSAH patients. So, what about the poor-grade patients? Is there still a better marker for predicting both good-grade and poor-grade aSAH patients? A good biomarker should be generalizable. As mentioned in this article, the poor-grade aSAH patients experience dramatic inflammation and WBC count elevations, so WBC count is not a good marker for them. On the other hand, for patients with certain immune deficiency diseases, WBC count is not a good way to make predictions.2 Therefore, a more specific marker is still needed.
DCI following aSAH occurs in up to 30% of patients, and it is characterized by delayed onset of cerebral ischemia, leading to motor deficits, cognitive dysfunction, and reduced quality of life.3 Cerebral vasospasm is one of the important contributors to DCI.4 A recent study by Vellimana et al5 suggested that MMP-9 expression and activity increased after SAH and MMP-9 inhibition led to decreased vasospasm and neurological deficits. So, will MMP-9 might be a marker for predicting DCI after aSAH. Additionally, a recent published article by Matsumoto Atsushi et al indicated that histidine-rich glycoprotein could be a predictor of vasospasm following aSAH, but the patient number is limited (7 controls and 14 aSAH patients).6 Further clinical research should be carried out to provide more evidence.
DCI following aSAH is a multifactorial pathophysiological process and it is of great significance to find out a specific biomarker to predict it in clinical scenarios.
The author has no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.
1. Al-Mufti F, Misiolek KA, Roh D, et al. White blood cell count improves prediction of delayed cerebral ischemia following aneurysmal subarachnoid hemorrhage. Neurosurgery. 2019;84(2):397-403.
2. Miyamoto S, Hara T, Tabei Y, Honma H, Kondo T, Oka S. Aneurysmal subarachnoid hemorrhage in a patient with human immunodeficiency virus type 1 infection. Case report. Neurol Med Chir (Tokyo). 2006;46(7):348-352.
3. Schweizer TA, Al-Khindi T, Macdonald RL. Mini-mental state examination versus montreal cognitive assessment: rapid assessment tools for cognitive and functional outcome after aneurysmal subarachnoid hemorrhage. J Neurol Sci. 2012;316(1-2):137-140.
4. Francoeur CL, Mayer SA. Management of delayed cerebral ischemia after subarachnoid hemorrhage. Crit Care. 2016;20(1):277.
5. Vellimana AK, Zhou ML, Singh I, et al. Minocycline protects against delayed cerebral ischemia after subarachnoid hemorrhage via matrix metalloproteinase-9 inhibition. Ann Clin Transl Neurol. 2017;4(12):865-876.
6. Matsumoto A, Nakamura T, Shinomiya A, et al. Histidine-rich glycoprotein could be an early predictor of vasospasm after aneurysmal subarachnoid hemorrhage. Acta Med Okayama. 2019;73(1):29-39.