Abstract TMP12: Does Prehospital Magnesium Sulfate Differentially Improve Outcome in Hyperacute Stroke Patients With Higher Pretreatment Blood Pressure?
Introduction: Magnesium sulfate (Mg) has blood pressure (BP) lowering, cerebral blood flow enhancing, and neuroprotective effects in preclinical and clinical studies. In the IMAGES phase 3 trial, Mg up to 12h after onset showed no benefit in acute stroke, but was associated with improved outcome in patients with higher blood pressure at entry.
Hypothesis: We tested the hypothesis that ultra-early Mg improves functional outcome in acute stroke patients with higher baseline BP.
Methods: FAST-MAG is a multicenter, double-blind, randomized, placebo-controlled trial of paramedic-initiated Mg, administered to patients with suspected stroke within 2h of symptom onset. The primary analysis showed neutral effect of Mg. This secondary analysis examines rates of functional independence (mRS 0-2) at 3m for Mg and placebo for different field BP groups.
Results: Among 1622 patients with acute cerebrovascular disease, age was 69.6 (±13.4), 42% female, entry deficit severity in the field was LAMS 3.8 (±1.2), and first post-enrollment NIHSS in the ED was 11.5 (±9.9). Systolic blood pressure prior to enrollment was higher among patients with intracerebral hemorrhage (ICH) than acute cerebral ischemia (ACI), 175 (±25) vs 155 (±27), p < .001. The Figure shows the Forest plot for Mg vs placebo and functional independence among blood pressure groups. Heterogeneity of treatment effect was noted in the all-cerebrovascular patients population (p < .01), with fewer independent outcomes with Mg than placebo among patients with higher entry BPs.
Analysis of Functional Independence (mRS 0-2) at 90 Days in Prespecified Subgroups
Conclusion: This analysis did not confirm the prior finding of magnesium sulfate benefit among acute stroke patients with elevated blood pressure (and actually provided a signal in the opposing direction). Mg was not demonstrated to improve outcome when started in the first 2h of onset among patients with acute cerebrovascular disease and higher blood pressures.
Author Disclosures: P.H. Johnson-Black: None. S. Starkman: None. N. Sanossian: None. D. Liebeskind: None. S. Stratton: None. M. Eckstein: None. F. Pratt: None. R. Conwit: None. S. Hamilton: None. C. Hemphill: None. J. Saver: None.
- © 2016 by American Heart Association, Inc.