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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

CharacteristicControlActive
Total Enrolled33 patients
Successfully Treated27 patients
Mean Age49.9 ± 11.8 years
Female76% (22/29)
Currently Smoking48% (14/29)
Hypertension62% (18/29)
Diabetes17% (5/29)
Aneurysm Clipped38% (11/29)
Aneurysm Coiled62% (18/29)
Median WFNS Grade2
Modified Fisher Grade 324 patients
Modified Fisher Grade 45 patients
Hunt & Hess Grade 320 patients
Hunt & Hess Grade 43 patients

Arms

FieldNeurapheresis Treatment
InterventionENROUTE Neurapheresis CSF Management System with dual-lumen intrathecal catheter for extracorporeal CSF filtration, removing blood products and returning filtered CSF
DurationUp to 72 hours of filtration

Outcomes

OutcomeTypeControlInterventionHR / OR / RRP-value
Hijdra Sum Score reduction from enrollment to catheter removalPrimary65% mean reduction (25.6 to 7.5 median HSS)<0.001
CSF red blood cell reductionSecondary86% mean reduction (540×10⁹ to 30×10⁹ cells/L)0.003
CSF protein reductionSecondary82% mean reduction (3.99 to 0.56 g/L)0.003
Catheter placement successSecondary93% (27/29 attempted)
Median filtration timeSecondary37:00 hours (IQR 24:03-38:52)
Patients maintaining/improving GCSSecondary92% (25/27)
Patients at home at 30 daysSecondary64% (16/25)
Total adverse eventsAdverse5 events in 4 patients
Serious adverse eventsAdverse1 event (transtentorial herniation, resolved)
Localized pain (legs/back)Adverse2 events
HeadachesAdverse2 events
Delayed cerebral ischemiaAdverse11% (3/27)
Shunt-dependent hydrocephalusAdverse19% (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)

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

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

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