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PILLAR-XT

Prospective Trial of Cerebrospinal Fluid Filtration After Aneurysmal Subarachnoid Hemorrhage via Lumbar Catheter Extension

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Year of Publication: 2025

Authors: Spiros L. Blackburn, Marc A. Babi, Andrew W. Grande, ..., Aaron R. McCabe

Journal: Neurocritical Care

Citation: Neurocrit Care. 2025. https://doi.org/10.1007/s12028-025-02328-8

Link: https://doi.org/10.1007/s12028-025-02328-8

PDF: https://www.ahajournals.org/doi/pdf/10.1...EAHA.119.025399

Clinical Question

What is the safety, tolerability, and filtration capability of the Neurapheresis CSF Management System for removing blood and blood lysis products from hemorrhagic CSF in patients with aneurysmal subarachnoid hemorrhage?

Bottom Line

The PILLAR-XT study demonstrated that extracorporeal CSF filtration using the Neurapheresis system safely and significantly accelerated intracranial blood elimination, with 65% reduction in Hijdra Sum Score and dramatic reductions in CSF red blood cells (86%) and protein (82%) compared to standard care.

        Major Points
        PILLAR-XT was a prospective, single-arm, investigational device exemption study at 6 sites
33 patients enrolled, 29 attempted catheter placement, 27 successfully treated (93% success rate)
Dual-lumen intrathecal catheter placed L3-L4 or L4-L5 with extracorporeal filtration for up to 72 hours
Primary outcome: 65% reduction in Hijdra Sum Score from enrollment to catheter removal
CSF red blood cell counts reduced by mean 86% and protein by mean 82%
Median filtration time 37 hours with median waste rate 5.7 mL/hr
Reached normal CSF protein levels in 2.1 days vs never achieving normal in standard care
Excellent safety profile: 5 adverse events in 4 patients, all mild-moderate severity
92% of patients maintained or improved Glasgow Coma Scale from admission to ICU discharge
64% of patients were at home at 30 days

      

Design

Study Type: Prospective, single-arm, investigational device exemption study

Randomization:

Blinding: Open-label, no blinding

Enrollment Period: December 2018 - January 2021

Follow-up Duration: 30 days

Centers: 6

Countries: United States

Sample Size: 27

Analysis: Paired t-tests for HSS and CSF parameters, descriptive statistics, interrater reliability analysis

Inclusion Criteria

Age 18-70 years
Informed consent by patient or legally authorized representative
Modified Fisher Grade 2, 3, or 4
Hunt & Hess I-IV
First aneurysmal SAH confirmed by CT scan and secured via clipping or coiling
Patient ≤48 hours post bleeding event
World Federation of Neurosurgical Societies (WFNS) Grades I-IV
Patient indicated for ventriculostomy (later criterion)

Exclusion Criteria

Coagulopathy that cannot be reversed
Pregnancy
SAH due to mycotic aneurysm or arteriovenous malformation
Acute myocardial infarction or unstable angina
Uncontrolled diabetes at catheter placement
Creatinine >2.0 mg/dl
Supratentorial mass lesions ≥15 cc
≥2 mm midline shift associated with infarction/edema
Infratentorial mass lesion ≥10 cc
Presence of subdural hematoma
Effacement of basilar cisterns
Vasospasm on admission
Thrombocytopenia (platelet count <100,000)
Spinal anatomy preventing catheter placement

Baseline Characteristics

Characteristic	Control	Active
Total Enrolled		33 patients
Successfully Treated		27 patients
Mean Age		49.9 ± 11.8 years
Female		76% (22/29)
Currently Smoking		48% (14/29)
Hypertension		62% (18/29)
Diabetes		17% (5/29)
Aneurysm Clipped		38% (11/29)
Aneurysm Coiled		62% (18/29)
Median WFNS Grade		2
Modified Fisher Grade 3		24 patients
Modified Fisher Grade 4		5 patients
Hunt & Hess Grade 3		20 patients
Hunt & Hess Grade 4		3 patients

Arms

Field	Neurapheresis Treatment
Intervention	ENROUTE Neurapheresis CSF Management System with dual-lumen intrathecal catheter for extracorporeal CSF filtration, removing blood products and returning filtered CSF
Duration	Up to 72 hours of filtration

Outcomes

Outcome	Type	Intervention	P-value
Hijdra Sum Score reduction from enrollment to catheter removal	Primary	65% mean reduction (25.6 to 7.5 median HSS)	<0.001
CSF red blood cell reduction	Secondary	86% mean reduction (540×10⁹ to 30×10⁹ cells/L)	0.003
CSF protein reduction	Secondary	82% mean reduction (3.99 to 0.56 g/L)	0.003
Catheter placement success	Secondary	93% (27/29 attempted)
Median filtration time	Secondary	37:00 hours (IQR 24:03-38:52)
Patients maintaining/improving GCS	Secondary	92% (25/27)
Patients at home at 30 days	Secondary	64% (16/25)
Total adverse events	Adverse	5 events in 4 patients
Serious adverse events	Adverse	1 event (transtentorial herniation, resolved)
Localized pain (legs/back)	Adverse	2 events
Headaches	Adverse	2 events
Delayed cerebral ischemia	Adverse	11% (3/27)
Shunt-dependent hydrocephalus	Adverse	19% (5/27)

Subgroup Analysis

Twenty of 26 patients returned to normal protein range (0.15-0.7 g/L) within 5.5 days of SAH onset. All adverse events were mild or moderate severity with complete resolution.

Criticisms

Single-arm design without randomized control group
Small sample size (27 patients successfully treated)
No direct comparison to standard lumbar drain or EVD
Historical comparison controls from different studies
EVDs were opened in 11/27 patients during treatment
Limited follow-up duration (30 days)
Study did not evaluate impact on long-term clinical outcomes
Potential selection bias inherent in device exemption study design

Funding

Supported by Minnetronix Neuro, Inc. and National Institute of Neurological Disorders and Stroke (R44NS110247)

Based on: PILLAR-XT (Neurocritical Care, 2025)