Introduction
Mild deficit is a relative contraindication to administration of IV rtPA for acute ischemic stroke. However, what constitutes “mild” deficit is vague. Prior studies showed patients with mild strokes have substantial disability rates at hospital discharge and at 90 days. We investigated whether the application of a new definition altered the rates of disability overall, and assessed the effects of thrombolysis.
Methods
This analysis included all adult acute ischemic stroke patients from a prospective registry of consecutive patients (UCSD SPOTRIAS database, 2003-2014) with 90-day mRS score available who were defined as “mild” using either: NIHSS 0-5 or a TREAT Task Force definition (NIHSS 0-5 and non-disabling based on pre-specified syndromes). Dichotomized 90-day mRS were compared between treated and untreated patients using the two definitions.
Results
Of 802 ischemic stroke patients with mRS scores available, 184 had baseline mRS(0) and met TREAT criteria; 45(24.5%) were rtPA-treated. Among treated patients, 35.6% had 90-day mRS(2-6), versus 28.8% in the untreated group, a non-significant difference after adjusting for baseline NIHSS (p=0.47). None of the 45 treated patients had symptomatic hemorrhage. Outcomes were similar using the simpler NIHSS 0-5 definition.
Conclusions
About one-third of mild stroke patients were not functionally independent at 90 days, irrespective of treatment or mild definition applied, calling into question the treatment efficacy of IV rtPA for mild strokes as well as what constitutes an appropriate definition of “mild”. Randomized studies are necessary to determine rtPA treatment efficacy in mild stroke patients.
Background:
Treatment of patients with acute ischemic stroke on mobile stroke units (MSUs) improves outcomes compared with management by standard emergency medical services ambulances and is associated with more patients treated with intravenous tPA (tissue-type plasminogen activator) in the first golden hour after last known normal. We explored the predictors and outcomes of first-hour treatment (FHT) compared with later treatment in an alternating-week cluster-controlled trial of MSUs.
Methods:
We analyzed all patients treated with intravenous tPA in the BEST-MSU Study (Benefits of Stroke Treatment Delivered by a Mobile Stroke Unit Compared to Standard Management by Emergency Medical Services). After stratifying by treatment timeframe, we identified factors associated with FHT. We performed adjusted analyses of the association between FHT and clinical outcome and modeled the shape of the relationship between last known normal–to–treatment time and excellent outcome.
Results:
Among 941 tPA-treated patients, 206 (21.8%) had lytic started within 60 minutes. Treatment on the MSU, older age, male sex, alert by 911, faster arrival on-scene and imaging, more severe stroke, atrial fibrillation, and absence of heart failure and pretreatment antihypertensive treatment were associated with FHT. Compared with later treatment, FHT was associated with higher adjusted odds ratio for 90-day modified Rankin Scale score of 0 to 1 (odds ratio, 1.87 [95% CI, 1.25–2.84];
P
=0.003). Among FHT patients, 68% achieved a 90-day modified Rankin Scale of 0 or 1 or returned to their baseline status. FHT was not associated with higher risk of hemorrhage and was associated with reduced risk of treating neurovascular mimics.
Conclusions:
FHT almost doubles the odds of excellent clinical outcome without increased risk compared with later treatment, which supports the use of MSUs.
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