Proenkephalin as marker for severity of aneurysmal subarachnoid hemorrhage: a pilot study

Objective: Several biomarker have shown associations with severity, vasospasm, ischemic events or outcome in aneurysmal subarachnoid hemorrhage. Yet no biomarker is used in daily clinical routine. Previously encephalin peptides were described as new biomarkers in ischemic stroke and traumatic brain injury. We sought to evaluate the usefulness of Proenkephalin A, a precursor protein of encephalin peptides, as biomarker in aneurysmal subarachnoid hemorrhage. Method: Eighteen consecutive patients with aSAH had plasma PENK A levels measured with a validated chemiluminescence sandwich immunoassay. The association of PENK A levels at admission with severity of SAH according to the World Federation of Neurological Surgeons (WFNS) grade after resuscitation was the primary endpoint. Levels of PENK A are analyzed with respect to different clinical and radiological scores as well as between patients with ICH, intraventricular hemorrhage, hydrocephalus, brain edema, vasospasm and ischemia. Results: Good grade patients showed median PENK A levels of 73.9pmol/l (IQR 69-80.4) and poor grade patients 117pmol/l (IQR 86-149). PENK A levels are significantly associated with severity of SAH as graded on the WFNS scale (p=0.03). No other parameter had a significant association. Conclusions: PENK A might be a useful serum marker in aSAH. Yet, larger trials also with serial PENK A assessments are needed