Oral Presentation Asia Pacific Stroke Conference 2024

Prehospital recruitment of ultra-early ICH patients in the STOP-MSU trial: implications for patient selection in ICH trials (107550)

Henry Zhao 1 2 , Nawaf Yassi 1 2 3 , Teddy Wu 4 , Leonid Churilov 1 5 , Vignan Yogendrakumar 1 2 , Henry Ma 6 , David Anderson 7 , Bruce Campbell 1 2 , Geoffrey Donnan 1 2 , Stephen Davis 1 2
  1. Royal Melbourne Hospital, Parkville, VIC, Australia
  2. Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
  3. Walter and Elizabeth Hall Insitute of Medical Research, Melbourne
  4. Department of Neurology, Christchurch Hospital, Christchurch, New Zealand
  5. Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia
  6. Department of Neurology, Monash Medical Centre, Melbourne
  7. Ambulance Victoria, Manningham, VIC, Australia

Introduction: The STOP-MSU RCT of tranexamic acid (TXA) in ICH <2h onset was the first haemostatic trial to include recruitment on a Mobile Stroke Unit (MSU). Although the trial did not demonstrate benefit of TXA, we investigated haematoma growth and outcomes in participants receiving prehospital treatment on the MSU compared to hospital-recruited patients.

Methods: We conducted a post-hoc analysis of the STOP-MSU trial assuming neutral treatment effect. We compared MSU-recruited to hospital-recruited patients for treatment time and haematoma growth (dichotomised 33%/6ml or absolute growth) and 90-day mRS (adjusted for age, sex, NIHSS and baseline ICH volume).

Results: Of n=201 trial patients, 44(21.9%) were recruited on MSU. There were no significant differences in baseline demographics including age, location, baseline volume, BP or glucose. MSU-recruited patients received faster treatment from onset (76min[IQR 67.5-100] vs 107min[IQR 97-118],p<0.001) and were treated more frequently ≤60min (OR 15.0[95%CI 3.0-75.1]). MSU patients had higher rates of growth on both dichotomised (52.3% vs 36.3%,aOR 2.0[95%CI 1.0-4.2],p=0.062) and absolute criteria (median 3.3ml[IQR 0.5-17.8] vs 0.8ml[IQR -0.8-6.5], mean 16.0ml[SD28.5] vs 7.0[SD15.4]). MSU patients trended towards poorer outcomes for mRS 0-3/return-to-baseline (40.9% vs 52.2%,aOR 0.75[95%CI 0.33-1.71]) and mortality (25.0% vs 14.7%,aOR 1.3[95%CI 0.4-3.8] with no modification from TXA (p-interaction=0.07).

Conclusions: MSU-recruited patients received significantly faster treatment and showed a two-fold increased odds of haematoma growth compared to hospital-recruited patients. Growth parameters were comparable or even surpassed previous TXA trials that required CTA spot-sign for eligibility. As such MSU-facilitated ultra-early recruitment may be key for optimal patient selection in acute ICH trials.