Targeting Hemoglobin to Reduce Delayed Cerebral Ischemia After Subarachnoid Hemorrhage

Abstract

Delayed cerebral ischemia (DCI) continues to be a sequela of aneurysmal subarachnoid hemorrhage (aSAH) that carries significant morbidity and mortality. Aside from nimodipine, no therapeutic agents are available to reduce the incidence of DCI. Pathophysiologic mechanisms contributing to DCI are poorly understood, but accumulating evidence over the years implicates several factors. Those have included microvessel vasoconstriction, microthrombosis, oxidative tissue damage, and cortical spreading depolarization as well as large vessel vasospasm. Common to these processes is red blood cell leakage into the cerebrospinal fluids (CSF) and subsequent lysis which releases hemoglobin, a central instigator in these events. This has led to the hypothesis that early blood removal may improve clinical outcome and reduce DCI. This paper will provide a narrative review of the evidence of hemoglobin as an instigator of DCI. It will also elaborate on available human data that discuss blood clearance and CSF drainage as a treatment of DCI. Finally, we will address a recent novel device that is currently being tested, the Neurapheresis CSF Management System™. This is an automated dual-lumen lumbar drainage system that has an option to filter CSF and return it to the patient.

Keywords: Cerebrospinal fluid filtration; Delayed cerebral ischemia; Subarachnoid hemorrhage; Vasospasm.

Figure 1.

Schematic representation of the Neurapheresis CSF Management System showing dual lumen catheter with bloody CSF removed via catheter fenestrations in the lumbar spine and “clean” CSF returned to the patient via fenestrations located at the distal catheter tip.

Figure 2.

CSF samples before and after filtration confirming significant reduction in RBCs and protein.

Figure 3.

Significant Reduction in Hijdra cisternal blood score before and after filtration using the Neurepharesis CSF Management