Needles, Numbers, and Nuance: Two Cases of Neuraxial Anesthesia in FXI Deficiency

Fatine Karkri, MD         Kimberly Mendoza, MD, PhD, MPH          Holgar Mua Fang, MD, MPH, DESAIC         Caroline Berube, MD, FRCPC

↑ Carrier screening = ↑ Incidental FXI deficiency

Bleeding phenotype correlates poorly with FXI activity → Bleeding history best guides neuraxial anesthesia (NA) risk

FXI 50% - Delphi consensus

Conservative threshold for NA

Case-by-case multidisciplinary pathway

FXI 30% - Observational series

Safe NA reported in
select asymptomatic patients

Patient 1

♀ 43 y/o G1P0

F11 variant by genetics

∅ Bleeding history, prior myomectomy

FXI 42% (35+0 weeks)

  Elective cesarean at 37+3 weeks

  Single‑shot spinal (uncomplicated)

QBL 1,233 mL

Discharged POD4

Patient 2

♀ 31 y/o G1P0

Heterozygous carrier

Minor prior bleeding

FXI 60% → 36% → 42% (35+2 weeks)

  Vaginal delivery at 39+5 weeks

  Labor epidural (uncomplicated)

QBL 808 mL

Discharged PPD2

Use bleeding history + targeted 3rd trimester FXI testing to guide NA decisions

Consider point‑of‑care viscoelastic testing (ROTEM/TEG) to complement FXI activity, although not yet validated

→ FXI is usually stable in pregnancy, consider lab variability
Interpret single intermediate FXI values in clinical context

Multidisciplinary team
Hematology-Obstetrics-Anesthesiology

→ Individualize NA decisions for FXI 30–50%

Multidisciplinary planning enabled safe NA in two asymptomatic patients with third‑trimester FXI ≈30-50%