The European Journal of Neurology recently published a risk score that allows early estimation of the probability for shunt dependency after subarachnoid hemorrhage. CHESS stands for Chronic Hydrocephalus Ensuing from SAH Score. This score can be helpful in deciding whether a permanent CSF diversion is needed in post-hemorrhage hydrocephalus (PHH).
Inclusion criteria for the study:
- admission and treatment of ruptured aneurysm within 48 hours post-ictus
- patient survives up to the time of decision-making for shunt placement
PHH was divided into 3 stages:
- acute (0-3 days post-SAH)
- subacute (4-13 days)
- chronic (>=14 days)
All patients with acute PHH underwent CSF diversion via EVD or lumbar drainage. Continuous drianage was maintained for at least 7 days. Patients who developed subacute PHH were treated with serial lumbar punctures.
The drain (EVD or lumbar drain) was challenged starting the second week of SAH in the absence of clinical contraindications (ICP issues or infection). Drain was closed for 48 hours with CT scans performed before and after clamping.
Patients considered to fail EVD/LD challenge if:
- they deteriorate neurologically and/or they have increased headaches that improve with unclamping the drain
- sustained ICP increase >20 cm H20
- radiographic evidence of increased ventricular size compared to baseline CT (CT prior to clamping)
Shunt placement was performed after two unsuccessful clamping trials.
The following independent risk factors were identified and included in the CHESS:
- Hunt and Hess grade ≥IV (1 point, OR = 2.65)
- aneurysm in posterior circulation (1 point, OR = 2.37)
- (+) IVH on initial CT (1 point, OR = 2.41)
- (+) acute PHH (4 points, OR = 9.36)
- early cerebral infarction on follow-up CT scan (1 point, OR = 2.29)
The ROC curve between the CHESS and shunt rates showed a significant cutoff at 6 points.
- CHESS score ≥6 = 6.74-fold higher risk for shunt dependency (P < 0.0001)
- CHESS score <6 points showed NPV of 84.9%.
- CHESS <2 points showed NPV of 98.5%
- avoid unnecessary prolonged EVD/LD weaning (and reduce catheter-related meningitis)
- reduce readmission rates (for delayed shunt placement)
Based on this score, patients can be stratified into:
- high risk – score of 6-8
- moderate risk – 2-5
- low risk – 0-1
A shunt-restrictive policy as well as an early transfer to rehabilitation can be considered in SAH patients with low CHESS scores.
Jabbarli, R. et al. “The CHESS Score: A Simple Tool For Early Prediction Of Shunt Dependency After Aneurysmal Subarachnoid Hemorrhage”. Eur J Neurol (2016).