Study objectives: The role of blood pressure in acute brain ischemia has been long been a subject of controversy. Although it is generally accepted that too high a blood pressure can harm survival, the lower end of the spectrum is seldom considered. Is there a range of blood pressure below which chances of survival are again poorer so that the survival curve is no longer a linear one? We determine how the mean arterial pressure (MAP), systolic blood pressure, or diastolic blood pressure in the emergency department (ED) correlates with mortality in transient ischemic attack (TIA).Methods: The records of all patients with a final diagnosis of TIA (International Classification of Diseases, Ninth Revision code 435) presenting to the Saint Mary's Hospital ED in a 6-month period was performed. Data on ED blood pressure measurements and dates of death and last follow-up were abstracted. All consecutive patients in the mentioned period were captured; all but 1 patient (subsequently deceased) had blood pressure measurements recorded. Associations with survival were evaluated according to fitting univariate Cox proportional hazards models and summarized by calculating risk ratios (RR, risk/10-unit decrease) and 95% confidence intervals (CIs). This study was approved by the authors' institutional review board.Results: Among the 72 patients with TIAs, 8 deaths occurred, with mean time until death of 196.3 deaths (median, 173 days). The 8 deaths occurred at 17, 17, 61, 145, 201, 321, 377, and 431 days after the initial ED visit. Among the remaining 64 patients who were alive at last follow-up, the mean duration of follow-up was 275.6 days (median 310; range 0 to 463 days). According to univariate Cox models, patients with low systolic blood pressure were more likely to have poorer survival (RR 1.4, 95% CI 1.02 to 1.8, P=.036). Likewise, patients with low MAP were more likely have poorer survival (RR 2.0, 95% CI 1.1 to 3.5, P=.026). There was also a trend for patients with low diastolic blood pressure to have poorer survival (RR 2.1, 95% CI 0.99 to 4.7, P=.054).Conclusion: Low MAP, systolic blood pressure, or diastolic blood pressure in the ED in the setting of a TIA all appear to be associated with poorer survival. These findings argue for judicious use of antihypertensive medications to patients with TIA in the acute setting.