Implementation of an institution-wide acute stroke algorithm: Improving stroke quality metrics.

BACKGROUND: In May 2012, an updated stroke algorithm was implemented at Vanderbilt University Medical Center. The current study objectives were to: (1) describe the process of implementing a new stroke algorithm and (2) compare pre- and post-algorithm quality improvement (QI) metrics, specificaly door to computed tomography time (DTCT), door to neurology time (DTN), and door to tPA administration time (DTT). METHODS: Our institutional stroke algorithm underwent extensive revision, with a focus on removing variability, streamlining care, and improving time delays. The updated stroke algorithm was implemented in May 2012. Three primary stroke QI metrics were evaluated over four separate 3-month time points, one pre- and three post-algorithm periods. RESULTS: The following data points improved after algorithm implementation: average DTCT decreased from 39.9 to 12.8 min (P < 0.001); average DTN decreased from 34.1 to 8.2 min (P ≤ 0.001), and average DTT decreased from 62.5 to 43.5 min (P = 0.17). CONCLUSION: A new stroke protocol that prioritized neurointervention at our institution resulted in significant lowering in the DTCT and DTN, with a nonsignificant improvement in DTT.

Routine clinical evaluation of cerebrovascular reserve capacity using carbogen in patients with intracranial stenosis.

BACKGROUND AND PURPOSE: A promising method for identifying hemodynamic impairment that may serve as a biomarker for stroke risk in patients with intracranial stenosis is cerebrovascular reactivity (CVR) mapping using noninvasive MRI. Here, abilities to measure CVR safely in the clinic using hypercarbic hyperoxic (carbogen) gas challenges, which increase oxygen delivery to tissue, are investigated. METHODS: In sequence with structural and angiographic imaging, blood oxygenation level-dependent carbogen-induced CVR scans were performed in patients with symptomatic intracranial stenosis (n=92) and control (n=10) volunteers, with a subgroup of patients (n=57) undergoing cerebral blood flow-weighted pseudocontinuous arterial spin labeling CVR. Subjects were stratified for 4 substudies to evaluate relationships between (1) carbogen and hypercarbic normoxic CVR in healthy tissue (n=10), (2) carbogen cerebral blood flow CVR and blood oxygenation level-dependent CVR in intracranial stenosis patients (n=57), (3) carbogen CVR and clinical measures of disease in patients with asymmetrical intracranial atherosclerotic (n=31) and moyamoya (n=29) disease, and (4) the CVR scan and immediate and longer-term complications (n=92). RESULTS: Noninvasive blood oxygenation level-dependent carbogen-induced CVR values correlate with (1) lobar hypercarbic normoxic gas stimuli in healthy tissue (R=0.92; P<0.001), (2) carbogen-induced cerebral blood flow CVR in patients with intracranial stenosis (R=0.30-0.33; P<0.012), and (3) angiographic measures of disease severity both in atherosclerotic and moyamoya patients after appropriate processing. No immediate stroke-related complications were reported in response to carbogen administration; longer-term neurological events fell within the range for expected events in this patient population. CONCLUSIONS: Carbogen-induced CVR elicited no added adverse events and provided a surrogate marker of cerebrovascular reserve consistent with intracranial vasculopathy.

Right Hemisphere Ischemia is more likely to Cause Falsely "Mild" Symptoms and Poor Outcomes without Thrombolysis.

BACKGROUND: Rapidly improving or mild symptoms is the most common reason that acute stroke patients arriving within the approved time window are not treated with intravenous tissue-type plasminogen activator (IV tPA). We reviewed outcomes at discharge for patients excluded from IV tPA because of rapidly improving or mild symptoms, with the aim of being better able to identify patients who may benefit from thrombolysis. METHODS: All patients between April 2006 and June 2010 from our center who did not receive IV tPA with "rapidly improving or mild symptoms" as the reason for exclusion were identified. Poor outcome was defined as hospital discharge to location other than home or inability to ambulate independently at discharge. RESULTS: There were 66 patients excluded from tPA treatment because of rapidly improving or mild symptoms. Eleven patients (16.7%) had poor outcomes. In 6 patients (9%), poor outcome was due to neurologic deficit. All 6 patients with neurologic deficits had right hemisphere strokes, and one also had cerebellar infarcts. CONCLUSIONS: Patients presenting with rapidly improving or mild symptoms do not universally have good outcomes. This may be particularly true in the case of right hemispheric ischemia where deficits are not fully reflected by NIHSS score. If a patient with a low NIHSS score is otherwise a candidate for tPA, a more detailed exam is warranted to better identify potentially disabling deficits that might benefit from thrombolysis.

Intravenous rt-PA is not associated with increased risk of hemorrhage in patients with intracranial aneurysms.

BACKGROUND AND PURPOSE: The presence of an intracranial aneurysm is listed as an exclusion criterion for the administration of recombinant tissue-plasminogen activator (rt-PA). This study was designed to test the hypothesis that the administration of rt-PA is safe in patients who have an unruptured intracranial aneurysm. METHODS: We performed a retrospective analysis of all acute ischemic stroke patients treated with rt-PA at our tertiary care academic medical center from June 2006 to June 2010 who also received intracranial vessel imaging. Baseline clinical characteristics were prospectively determined. Identification of hemorrhage and the presence of aneurysm were obtained from radiology report, and neuro-imaging findings were confirmed by study investigators. Symptomatic intracerebral hemorrhage (sICH) was defined according to National Institutes of Neurological Disorders and Stroke criteria. RESULTS: Five percent of patients (8/172) had at least one intracranial aneurysm on vessel imaging. A total of seven patients (4 %) had sICH. There was no significant difference in intracranial aneurysms between patients with or without sICH [1/7 (14 %) vs. 7/165 (4.2 %), p = 0.29]. In one patient with sICH and an intracranial aneurysm, the location of hemorrhage was distant from the aneurysm. The only predictors found for sICH in our cohort were atrial fibrillation (p = 0.03) and infarct size (p = 0.0004). CONCLUSIONS: Incidental intracranial aneurysms are common in patients who were present with acute ischemic stroke and not associated with sICH in our population. The concern that these patients are at increased risk of hemorrhage after thrombolysis may not be warranted.

No increased risk of symptomatic intracerebral hemorrhage after thrombolysis in patients with European Cooperative Acute Stroke Study (ECASS) exclusion criteria.

BACKGROUND AND PURPOSE: The European Cooperative Acute Stroke Study (ECASS) III trial used additional exclusion criteria not present in current guidelines for thrombolytic therapy in the United States (age >80 years; National Institutes of Health Stroke Scale >25, combination of previous stroke and diabetes, aggressive measures required to control blood pressure [intravenous infusion], and oral anticoagulant treatment). We tested the hypothesis that thrombolysis is not safe in patients with 1 of the additional exclusion criteria. METHODS: All patients treated with intravenous tissue-type plasminogen activator for acute stroke at our center between June 2006 and June 2010 were identified (n=191), and stratified based on presence of each of the exclusion criteria. Primary outcomes were rate of symptomatic intracerebral hemorrhage and in-hospital mortality. Additionally, patients with and without symptomatic intracerebral hemorrhage were analyzed for differences in baseline characteristics. RESULTS: No exclusion criterion was associated with increased risk of symptomatic intracerebral hemorrhage. Symptomatic intracerebral hemorrhage was associated with atrial fibrillation (5 of 9 [55%], versus 35 of 182 [19.2%]; P=0.021), larger final infarct volume (mean 173 mL(3) versus 42 mL(3); P=0.0002), and elevated glucose (mean 166 mg/dL versus 127 mg/dL; P=0.038). There was higher mortality in patients >80 years (5 of 31 [16%] versus 6 of 160 [4%]; P=0.0186) and those with National Institutes of Health Stroke Scale >25 (2 of 5 [40%] versus 7 of 159 [4.4%]; P=0.025). CONCLUSIONS: In our cohort, none of the more stringent exclusion criteria from ECASS III were associated with increased risk of symptomatic intracerebral hemorrhage. Prospective randomized studies are needed clarify the safety and efficacy of tissue-type plasminogen activator in these patients through all treatment time windows.