Faculty Bibliography

BACKGROUND AND PURPOSE/OBJECTIVE:Early neurologic improvement (ENI) in patients treated with alteplase has been shown to correlate with functional outcome. However, the definition of ENI remains controversial and has varied across studies. We hypothesized that ENI defined as a percentage change in the National Institute of Health Stroke Scale (NIHSS) score (percent change NIHSS score) at 24-hours would better correlate with favorable outcomes at 3 months than ENI defined as the change in NIHSS score (delta NIHSS score) at 24 hours. METHODS:Retrospective analysis of prospectively collected single-center quality improvement data was performed of all acute ischemic stroke (AIS) patients treated with alteplase. We examined delta NIHSS score and percent change NIHSS score in unadjusted and adjusted logistic regression models as predictors of a favorable outcome at 3 months (defined as mRS 0-1). RESULTS:Among 586 patients who met the inclusion criteria, 194 (33.1%) had a favorable outcome at 3 months. In fully adjusted models, both delta NIHSS score (OR per point decrease 1.27; 95% confidence interval [CI] 1.19-1.36) and percent change NIHSS score (OR per 10 percent decrease 1.17; 95% CI 1.12-1.22) were associated with favorable functional outcome at 3 months. Receiver operating characteristic (ROC) curve comparison showed that the area under the ROC curve for percent change NIHSS score (.755) was greater than delta NIHSS score (.613) or admission NIHSS (.694). CONCLUSIONS:Percentage change in NIHSS score may be a better surrogate marker of ENI and functional outcome in AIS patients after receiving acute thrombolytic therapy. More studies are needed to confirm our findings.

BACKGROUND:There is limited data on predictors of symptomatic intracranial haemorrhage (sICH) in patients who underwent mechanical thrombectomy. In this study, we aim to determine those predictors with external validation. METHODS:and t tests to identify independent predictors of sICH with p<0.1. Significant variables were then combined in a multivariate logistic regression model to derive an sICH prediction score. This score was then validated using data from the Blood Pressure After Endovascular Treatment multicentre prospective registry. RESULTS:We identified 578 patients with acute ischaemic stroke who received thrombectomy, 19 had sICH (3.3%). Predictive factors of sICH were: thrombolysis in cerebral ischaemia (TICI) score, Alberta stroke program early CT score (ASPECTS), and glucose level, and from these predictors, we derived the weighted TICI-ASPECTS-glucose (TAG) score, which was associated with sICH in the derivation (OR per unit increase 1.98, 95% CI 1.48 to 2.66, p<0.001, area under curve ((AUC)=0.79) and validation (OR per unit increase 1.48, 95% CI 1.22 to 1.79, p<0.001, AUC=0.69) cohorts. CONCLUSION/CONCLUSIONS:High TAG scores are associated with sICH in patients receiving mechanical thrombectomy. Larger studies are needed to validate this scoring system and test strategies to reduce sICH risk and make thrombectomy safer in patients with elevated TAG scores.

Background: Stroke code activations are a valuable tool in providing prompt care to stroke patients who may be eligible for treatments such as tPA and endovascular interventions. However, stroke codes involve the immediate attention of many members of the healthcare team and significant hospital resources. The National Institutes of Health Stroke Scale (NIHSS) is commonly used to evaluate stroke severity; however, even patients with an NIHSS score of zero can have ongoing neurologic symptoms and disability. Confusion over the goals of stroke codes and the appropriate situations for their use may contribute to unnecessary activations.
Objective(s): The purpose of this analysis was to evaluate the frequency of stroke code activations in situations where activating a stroke code provides little potential benefit in terms of therapeutic options over a non-emergent neurology consult.
Method(s): We reviewed the records for all emergency department (ED) stroke code activations over the first five months of 2018, looking specifically at cases with an NIHSS score of zero. Within this pool, we identified cases where the patient was documented as being asymptomatic during initial ED evaluation as their symptoms had resolved (transient ischemic attack), as well as those who had been symptomatic for over 24 hours and were outside the therapeutic window. These patients were not eligible for emergent therapeutic intervention. Thus, these were cases in which a stroke code activation was avoidable.
Result(s): Of the 120 stroke codes with an NIHSS of zero, 39 (32.5%) involved patients whose symptoms had completely resolved prior to arrival. Another three cases involved patients who had been symptomatic for over 24 hours and were outside the therapeutic window. Thus, of the stroke code activations with an NIHSS of zero in this time period, 42 (35%) were avoidable as these patients would not have been considered candidates for emergent treatment.
Conclusion(s): Clarification and reinforcement of appropriate criteria for stroke code activation have the potential to reduce overutilization of resources in situations unlikely to affect acute therapeutic management. Addressing this would allow for a reduction in the burden on healthcare professionals and ED resources

Objectives: To demonstrate the development and use of an acute imaging protocol for the metabolic assessment of tissue viability during acute stroke.
Method(s): The DAWN and DEFUSE 3 trials (1,2) have demonstrated that there is much to gain from the use of physiologically based guidelines to extend the use of mechanical recanalization. Literature reports provide strong data supporting the use of brain tissue sodium concentration (TSC) as a biomarker for identifying physiologically non-viable tissue during evolving brain ischemia (3,4). Testing this hypothesis in vivo, in humans, have been previously hampered by acquisition times that were long for routine clinical use. Recent developments in MRI data acquisition and hardware make it possible to acquire the data to provide the aforementioned assessment in under 5 minutes at a level of signal-to-noise ratio (SNR) and spatial resolution compatible with physiologically driven MRI scans such as diffusion weighted imaging and perfusion imaging. This was achieved using an Ultra-Short-Echo Time sequence with optimal acquisition throughput (TPI, TE/TR 0.3/100 ms, p 0.2). Signal excitation/reception was performed using a patient-friendly double-tuned (¹H/²³Na) birdcage coil (Quality Electrodynamics Inc., Mayfield Heights, Ohio). The protocol was implemented on a MAGNETOM Skyra 3 Tesla scanner at NYU's Tisch hospital. The scanner is located adjacent (20 feet) to the neuro interventional suite where patients are recanalized. Subject's anesthesia was maintained (FabiusMRI, DraegerInc., Telford, PA) and physiological status continuously monitored using MRI-compatible equipment (Expression MR400, Phillips Healthcare, Andover, MA).
Result(s): After phantom validation and healthy volunteer studies to determine the quantitative performance of the data acquisition techniques the protocol was used on post-endovascular thrombectomy subjects (n 3), immediately upon procedure completion and under its own IRB approved protocol. During these studies, the use of the proposed methodology was found to be compatible with the clinical care of the subjects. Specifically, performing the required scans was not found to interfere with the subject's post-recanalization care. Tissue sodium concentration data were, likewise, found to meet the required levels of SNR to provide the quantitative assessment mentioned above. A representative data set from one of these sessions is shown in figure 1. This mechanically-recanalized patient had an area of non-salvaged tissue in the left parietal lobe that is clearly depicted on the ²³Na MRI scan. The TSC in this area was 76 mM at the time of the scan. (Figure presented)
Conclusion(s): This work demonstrates that state-of-the-art MRI methodology can be used to provide a clinically viable imaging protocol for evaluating the use of sodium MRI as a quantitative biomarker for identifying physiologically viable tissue during evolving brain ischemia

Background and Aims: Contemplating the use of N-acetylcysteine as a neuroprotectant, with dextran as an antithrombotic for patients with NIHSS less than or equal to 5, we quantified treatment-relevant clinical characteristics of a sample of this patient population at a single stroke center over one year.
Method(s): Patients with NIHSSResult(s): One-hundred twenty-eight of 310 (41%) patients with ischemic stroke had NIHSSConclusion(s): Minor stroke symptoms may not be captured by the current NIHSS. This population rarely had renal or hepatic failure, making them good candidates for combination N-acetylcysteine and dextran

BACKGROUND AND PURPOSE/OBJECTIVE:Patients with intracerebral hemorrhage (ICH) frequently present with hypertension, but it is unclear if this is due to pre-existing hypertension (prHTN) or to the bleed itself or associated pain. We sought to assess the relationship between prHTN and admission systolic blood pressure (aBP) and bleed severity. METHODS:We retrospectively assessed the relationship between prHTN and aBP and NIHSS in patients with ICH at 3 institutions. RESULTS:Of 251 patients, 170 (68%) had prHTN based on history of hypertension/antihypertensive use. Median aBP was significantly higher in those with prHTN (155 mm Hg (IQR 135-181) versus 139 mm Hg (IQR 124-158), P < .001). Patients with left ventricular hypertrophy (LVH) on electrocardiogram (ECG) or transthoracic echocardiogram (TTE) had significantly higher aBP than those without LVH (median aBP 195 mm Hg (IQR 155-216) for patients with LVH on ECG versus 147 mm Hg (IQR 129-163) for patients with no LVH on ECG, P < .001; median aBP 181 mm Hg (IQR 153-214) for patients with LVH on TTE versus 152 mm Hg (IQR 137-169) for patients with no LVH on TTE, P = .01). prHTN was associated with a higher median NIHSS (11 (IQR 3-20) for patients with history of hypertension/antihypertensive use versus 6 (IQR 1-14) for patients without this history (P = .02); 9 (IQR 3-19) versus 5 (IQR 2-13) for patients with/without LVH on ECG (P = .085); and 10 (IQR 5-18) versus 5 (IQR 1-13) for patients with/without LVH on TTE (P = .046). CONCLUSIONS:Patients with ICH who have prHTN have higher aBP and NIHSS, suggesting that prHTN may worsen reactive hypertension in the setting of ICH.