Statistical assessment of the prognostic and the predictive value of biomarkers-A biomarker assessment framework with applications to traumatic brain injury biomarker studies

Studies that investigate the performance of prognostic and predictive biomarkers are commonplace in medicine. Evaluating the performance of biomarkers is challenging in traumatic brain injury (TBI) and other conditions when both the time factor (i.e. time from injury to biomarker measurement) and different levels or doses of treatments are in play. Such factors need to be accounted for when assessing the biomarker’s performance in relation to a clinical outcome. The Hyperbaric Oxygen in Brain Injury Treatment (HOBIT) trial, a phase II randomized control clinical trial seeks to determine the dose of hyperbaric oxygen therapy (HBOT) for treating severe TBI that has the highest likelihood of demonstrating efficacy in a phase III trial. Hyperbaric Oxygen in Brain Injury Treatment will study up to 200 participants with severe TBI. This paper discusses the statistical approaches to assess the prognostic and predictive performance of the biomarkers studied in this trial, where prognosis refers to the association between a biomarker and the clinical outcome while the predictiveness refers to the ability of the biomarker to identify patient subgroups that benefit from therapy. Analyses based on initial biomarker levels accounting for different levels of HBOT and other baseline clinical characteristics, and analyses of longitudinal changes in biomarker levels are discussed from a statistical point of view. Methods for combining biomarkers that are of complementary nature are also considered and the relevant algorithms are illustrated in detail along with an extensive simulation study that assesses the performance of the statistical methods. Even though the discussed approaches are motivated by the HOBIT trial, their applications are broader. They can be applied in studies assessing the predictiveness and prognostic ability of biomarkers in relation to a well-defined therapeutic intervention and clinical outcome.

Brain Oxygen Optimization in Severe Traumatic Brain Injury (BOOST-3): a multicentre, randomised, blinded-endpoint, comparative effectiveness study of brain tissue oxygen and intracranial pressure monitoring versus intracranial pressure alone

INTRODUCTION

Management of traumatic brain injury (TBI) includes invasive monitoring to prevent secondary brain injuries. Intracranial pressure (ICP) monitor is the main measurement used to that intent but cerebral hypoxia can occur despite normal ICP. This study will assess whether the addition of a brain tissue oxygenation (PbtO2) monitor prevents more secondary injuries that will translate into improved functional outcome.

METHODS AND ANALYSIS

Multicentre, randomised, blinded-endpoint comparative effectiveness study enrolling 1094 patients with severe TBI monitored with both ICP and PbtO2. Patients will be randomised to medical management guided by ICP alone (treating team blinded to PbtO2 values) or both ICP and PbtO2. Management is protocolised according to international guidelines in a tiered approach fashion to maintain ICP <22 mm Hg and PbtO2 >20 mm Hg. ICP and PbtO2 will be continuously recorded for a minimum of 5 days. The primary outcome measure is the Glasgow Outcome Scale-Extended performed at 180 (±30) days by a blinded central examiner. Favourable outcome is defined according to a sliding dichotomy where the definition of favourable outcome varies according to baseline severity. Severity will be defined according to the probability of poor outcome predicted by the IMPACT core model. A large battery of secondary outcomes including granular neuropsychological and quality of life measures will be performed.

ETHICS AND DISSEMINATION

This has been approved by Advarra Ethics Committee (Pro00030585). Results will be presented at scientific meetings and published in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03754114).

Predicting 90-Day Outcome After Thrombectomy: Baseline-Adjusted 24-Hour NIHSS Is More Powerful Than NIHSS Score Change

BACKGROUND AND PURPOSE

The National Institutes of Health Stroke Scale (NIHSS) measured at an early time point is an appealing surrogate marker for long-term functional outcome of stroke patients treated with endovascular therapy. However, definitions and analytical methods for an early NIHSS-based outcome measure that optimize power and precision in clinical studies are not well-established.

METHODS

In this post-hoc analysis of our prospective observational study that enrolled endovascular therapy-treated patients at 12 comprehensive stroke centers across the US, we compared the ability of 24-hour NIHSS, ΔNIHSS (baseline minus 24-hour NIHSS), and percentage change (NIHSS×100/baseline NIHSS), analyzed as continuous and dichotomous measures, to predict 90-day modified Rankin Scale (mRS) using logistic regression (adjusted for age, baseline NIHSS, glucose, hypertension, Alberta Stroke Program Early CT Score, time to recanalization, recanalization status, and intravenous thrombolysis) and Spearman ρ.

RESULTS

Of 485 patients in the BEST (Blood Pressure After Endovascular Stroke Therapy) cohort, 446 (92%) with 90-day follow-up data were included. An absolute 24-hour NIHSS, adjusted for baseline in multivariable modeling, had the highest predictive power of all definitions evaluated (aR² 0.368 and adjusted odds ratio 0.79 [0.75-0.84], P<0.001 for mRS score 0-2; aR² 0.444 and adjusted odds ratio 0.84 [0.8-0.86] for ordinal mRS). For predicting mRS score of 0-2 with a cut point, the second most efficient approach, the optimal threshold for 24-hour NIHSS score was ≤7 (sensitivity 80.1%, specificity 80.4%; adjusted odds ratio 12.5 [7.14-20], P<0.001), followed by percent change in NIHSS (sensitivity 79%, specificity 58.5%; adjusted odds ratio 4.55 [2.85-7.69], P<0.001).

CONCLUSIONS

Twenty-four-hour NIHSS, adjusted for baseline, was the strongest predictor of both dichotomous and ordinal 90-day mRS outcomes for endovascular therapy-treated patients. A dichotomous 24-hour NIHSS score of ≤7 was the second-best predictor. Although ΔNIHSS, continuous and dichotomized at ≥4, predicted 90-day outcomes, absolute 24-hour NIHSS definitions performed better.

Abstract TMP6: Optimal Early Clinical Endpoints for Long-Term Functional Outcome Prediction After Thrombectomy

Background: Early neurological recovery (ENR) is an attractive surrogate marker for long-term functional outcome of endovascularly-treated stroke patients. However, the optimal definition of 24-hour ENR that best predicts 90-day functional independence (modified Rankin Scale, mRS, 0-2) has not been established. We sought to determine ENR measure that best predicts 90-day mRS 0-2.

Methods: The prospective BEST cohort study includes consecutive adult patients treated with endovascular therapy at 12 comprehensive stroke centers. In this post-hoc analysis, we measured the ability of various thresholds of both 24-hour NIHSS and αNIHSS (baseline minus 24-hour) to predict 90-day mRS 0-2 using Youden’s index. The strength of the associations were assessed using logistic regression adjusted for age, glucose, hypertension, ASPECT score, time to recanalization, recanalization status, and thrombolytic treatment.

Results: Of 485 patients in the BEST cohort, 447 with 90-day follow-up were included in this study (228 females, mean age 68.05 ±15 years). The optimal Youden’s Index was achieved at 24 hour NIHSS of ≤7 (sensitivity 80.1%, specificity 80.4%, area under the curve [AUC] 0.855 [0.819-0.887], p<0.001; Figure). The optimal for αNIHSS cut point was ≥4 points (sensitivity 79%, specificity 58.5%, AUC 0.73 [0.685-0.77], p<0.001; Figure), which performed less well at outcome prediction than 24 hour NIHSS (difference between the AUCs 0.126, p<0.001; Figure). Strength of association between other common early clinical endpoints and outcome in this cohort are listed in the Table.

Conclusions: A 24-hour NIHSS ≤7 was the optimal measure to predict functional independence at 90 days in our multicenter, prospective cohort. Among αNIHSS thresholds, ≥4 points was optimal but performed less well. These findings should be validated in independent endovascular cohorts to establish a standard short-term outcome measure for both clinical and research scenarios.

Abstract TMP99: White Matter Hyperintensity Progression and Subsequent Incident Stroke: A Secondary Analysis of the ACCORD Trial

Introduction: Studies have shown that the volume of white matter hyperintensity (WMH) is a risk factor for stroke, but there are scarce data exploring the relationship between WMH progression on serial MRIs and subsequent risk of stroke.

Hypothesis: We hypothesize that WMH progression in the ACCORD trial increases the risk of subsequent incident stroke.

Methods: The exposure period was from baseline to month 40, during which an MRI was performed at both baseline and month 40. The primary outcome was incident ischemic stroke after the month 40 MRI until study completion. We fit Cox models to the primary outcome and included both the baseline and month 40 WMH volume as covariates, with the hazard ratio for the month 40 WMH volume of primary interest because it represents WMH progression in this model.

Results: We included 497 patients, of whom 53.3% were male and the mean (SD) age was 62.7 (5.7) years at enrollment. Mean (SD) follow-up after the month 40 MRI was 5.2 (1.8) years. Incident stroke occurred in 17 (3.4%) patients, in whom 2 were recurrent strokes and 15 were first-ever strokes. WMH progression was associated with subsequent stroke in the Cox model (HR 1.27, 95% CI 1.03-1.57, p=0.024) and remained significant after adjusting for patient age, history of prior stroke, and cigarette smoking (HR 1.33, 95% CI 1.07-1.65, p=0.010).

Conclusions: Although this preliminary analysis is underpowered, WMH progression, independent of absolute WMH burden, may be a risk factor for future stroke in diabetic patients. This novel finding could have translational implications - specifically that interventions which reduce the progression of WMH could, in turn, reduce future risk of stroke.

Abstract TP122: Peri-Procedural Stroke or Death in Stenting of Symptomatic Severe Intracranial Stenosis: A Post-Hoc Analysis of the SAMMPRIS Trial

Background and Purpose: There is limited data on predictors of 30-day stroke or death in patients with symptomatic intracranial atherosclerosis (sICAS) undergoing stenting. We aim to determine these predictors.

Methods: This is a post-hoc analysis SAMMPRIS including patients who underwent angioplasty/stenting. We determined associations between patient-specific, lesion-specific, and procedure-specific variables, and FDA-approved indications and the primary outcome (stroke or death at 30 days) using logistic regression analyses.

Results: We identified 213 patients; 30 patients (14.1%) met the primary outcome. The odds of stroke or death was higher with non-smokers vs. smokers (adjusted OR 4.46, 95% CI 1.79-11.1) and increasing lesion length in millimeters (adjusted OR 1.20, 95% CI 1.02-1.39). These had modest predictive value: absence of smoking history (sensitivity=66.7% and specificity=65.4%) and lesion length (Area Under Curve=0.606). Furthermore, event rates were not significantly different between patients with and without the FDA approved indication for stenting (15.9% vs. 12%, p = 0.437).

Conclusion: In SAMMPRIS patients who underwent angioplasty/stenting, neither clinical and neuroimaging variables nor the FDA indication for stenting reliably predicted the primary outcome. Further work in identifying reliable biomarkers of stroke/death in patients with sICAS is needed before considering new clinical trials of stenting.

Abstract 133: White Matter Hyperintensity and Cardiovascular Disease Outcomes: A Secondary Analysis of the SPRINT MIND Trial

Background: The Systolic Blood Pressure Intervention Trial (SPRINT) randomized patients to a goal SBP <120 mm Hg vs. <140 mm Hg . A subset of patients enrolled in SPRINT MIND, which performed a baseline MRI and measured white matter hyperintensity volume (WMHv). We evaluated the association between WMHv and cardiovascular events.

Methods: The primary outcome was a composite of stroke, MI, ACS, decompensated CHF, or CVD death. The secondary outcome was stroke. The WMHv was divided into quartiles. We fit Cox models to the outcomes and report adjusted hazard ratios for the quartiles of WMHv, and stratified by SPRINT treatment arm.

Results: Among 719 included patients, the mean WMHv in the quartiles was 0.34, 1.09, 2.61, and 10.8 mL. The primary outcome occurred in 51/719 (7.1%) and the secondary outcome in 10/719 (1.4%). The WMHv was associated with both outcomes (Table 1, Figure 1). After stratifying by treatment arm, we found the association persisted in the standard, but not intensive, treatment arm (Table 2). However, the interaction term between WMHv and treatment arm was not significant.

Conclusions: We observed that degree of WMH was associated with CVD and stroke risk in SPRINT MIND. The risk may be attenuated in patients randomized to intensive BP lowering. Trials are needed to determine if intensive BP lowering can prospectively reduce the high cardiovascular risk in patients with WMH.

Abstract WMP106: Why Are Women Less Represented in ICH Trials?

Background: Fewer women than men tend to be enrolled in clinical trials of intracerebral hemorrhage (ICH). It is unclear whether this reflects lower prevalence of ICH in women, selection bias, poor recruitment efforts, or other factors. We undertook this study to examine differences between women and men in the reasons for exclusion from the iDEF (Intracerebral hemorrhage Deferoxamine) trial.

Methods: The screen failure log included 29 different reasons for exclusion. Chi square statistics and p-values were used to evaluate whether women and men differed with regard to reason for screen failure.

Findings: The iDEF trial enrolled 294 subjects; 38.5% were women. A total of 8776 subjects were screen failures. Sex was missing in 58. The remaining 8718 were included in this analysis; 3982 women (45.7%) and 4736 men (54.3%) (p<0.0001). The enrollment rates were 2.8% in women vs. 3.7% in men (p=0.01). We were unable to obtain consent in 1.3% of women vs 1.7% of men (p=0.1), and patients/families declined participation in 1.3% of women vs. 1.3% of men (p=0.9). More women than men failed screening because of age >80 (22.4% vs 12.6%) and pre-existing DNR/DNI (3.7% vs. 2.8%). Conversely, fewer women than men failed screening because inability to administer study drug within 24 hour due to late presentation (6.6% vs 7.8%), admission NIHSS score <6 (10.2% vs 13.2%), coagulopathy (5.3% vs 7.5%), inability to comply with the protocol (0.7% vs 1.3%), abnormal renal function (1.9% vs 2.9%), drug/alcohol abuse (1.7% vs 3.7%), and presentation with confirmed aspiration or pneumonia (1.1% vs 1.8%).These differences were statistically significant.

Interpretation: Results from this multi-center, prospective, ICH trial indicate that lower rates of women enrollment may be attributed to older age and higher rates of pre-existing DNR/DNI orders. Inability to obtain consent or declining participation was similar between women and men, arguing against selection bias. Our findings should be confirmed in other ICH trials to determine if additional efforts are needed to improve women’s participation in future studies.

Funding: US National Institutes of Health and US National Institute of Neurological Disorders and Stroke (U01NS074425)

Abstract WMP14: Association of Systolic Blood Pressure, LDL Cholesterol, and Hgb A1c With White Matter Hyperintensity on MRI in the ACCORDION MIND Study

Introduction: While retrospective studies have shown that poor control of vascular risk factors is associated with progression of white matter hyperintensity (WMH), it has not been studied prospectively.

Hypothesis: We hypothesize that higher systolic blood pressure (SBP) mean, LDL cholesterol, and Hgb A1c will be correlated with WMH progression in diabetics.

Methods: This is a secondary analysis of the Memory in Diabetes (MIND) substudy of the Action to Control Cardiovascular Risk in Diabetes Follow-on Study (ACCORDION). The primary outcome was WMH progression, evaluated by fitting linear regression models to the WMH volume on the month 80 MRI and adjusting for the WMH volume on the baseline MRI. The primary predictors were the mean values of SBP, LDL, and A1c from baseline to month 80. We defined a good vascular risk factor profile as mean SBP <120 mm Hg and mean LDL <120 mg/dL.

Results: We included 292 patients, with a mean (SD) age of 62.6 (5.3) years and 55.8% male. The mean number of SBP, LDL, and A1c measurements per patient was 17, 5, and 12. We identified 86 (29.4%) patients with good vascular risk factor profile. In the linear regression models, mean SBP and LDL were associated with WMH progression and in a second fully adjusted model they both remained associated with WMH progression (Table). Those with a good vascular risk factor profile had less WMH progression (β Coefficient -0.80, 95% CI -1.42, -0.18, p=0.012).

Conclusions: Our data reinforce prior research showing that higher SBP and LDL is associated with progression of WMH in diabetics, likely secondary to chronic microvascular ischemia, and suggest that control of these factors may have protective effects. This study has unique strengths, including prospective serial measurement of the exposures, validated algorithmic measurement methodology for WMH, and rigorous adjudication of study data. Clinical trials are needed to investigate the effect of vascular risk factor reduction on WMH progression.

Abstract WP77: Final Infarct Volume May Predict Functional Outcome After Mild, Nondisabling Ischemic Stroke: Results From the PRISMS Trial

Introduction: In patients with acute cerebral ischemia (ACI) within 3h of onset with mild deficit judged as nondisabling at presentation, up to 20% experience poor functional outcome at 90 days. We tested the hypothesis that the presence of infarction at 24h would independently predict worse outcome at 3 months, and also explored the role of final infarct volume (FIV) on outcomes.

Methods: The phase 3b, randomized PRISMS trial compared intravenous alteplase to aspirin for mild (NIHSS 0-5), nondisabling stroke at <3 h from onset. In a prespecified analysis, we included patients with 24h MRI performed and excluded acute cerebral ischemia mimics. Central readers assessed Day 24h MRIs for acute infarct, chronic infarcts, and white matter hyperintensity (WMH) burden; FIV and WMH volumes were measured quantitatively using semi-automated software. The primary outcome was 3-month EQ5D scores, a measure of QOL, and the secondary outcome was modified Rankin Scale (mRS) scores, a measure of disability. Multivariable linear regression and proportional odds cumulative logit models were used to evaluate the association between (1) acute infarction presence and (2) FIV on the primary and secondary outcomes, respectively, adjusting for relevant covariates (Table 1).

Results: Of 313 patients enrolled, 273 had a final diagnosis of ACI and 212/273 (77%) had 24h MRI scans. Acute infarcts were present In 109 (51%), and median FIV was 1.20 mL (IQR 0.57-2.50). No association between presence of acute infarcts and 3-month EQ5D (p=0.84) or mRS (p=0.17) scores was observed (Table 1A). No association between FIV and EQ5D scores (p=0.31) was observed as well, but FIV was strongly associated with mRS scores (OR 1.11, 95% CI 1.04-1.18, p<0.001), in adjusted models (Table 1B).

Conclusions: Among patients presenting with mild, nondisabling ACI, FIV appears to be associated with worse functional outcome. Since this was a post-hoc analysis, this hypothesis requires further prospective study.

Abstract WP183: Borderzone Infarcts Predict Early Recurrence in Patients With Large Artery Atherosclerotic Subtype Despite Medical Treatment

Introduction: Large artery atherosclerosis subtype carries a high risk of early recurrent stroke despite medical management. Predictors of recurrence remain poorly understood. We hypothesized that borderzone infarcts are associated with a higher risk of recurrence.

Objectives: We aim to investigate infarct patterns and 90-day recurrence in patients with symptomatic intracranial and/or extracranial atherosclerotic disease.

Methods: We included consecutive patients admitted to NYU Langone Health (Manhattan and Brooklyn campuses) over 32-months with a diagnosis of acute ischemic stroke secondary to symptomatic intracranial or extracranial atherosclerosis. The primary predictor was infarct pattern (borderzone vs. non-borderzone infarction), defined in accordance to previous studies. Borderzone infarcts were divided into internal borderzone and cortical borderzone. We used univariate and multivariable cox-regression models to determine associations between infarct pattern and recurrent cerebrovascular events (RCVE) at 90-days.

Results: Fifty-five patients met the inclusion criteria; 38 were intracranial, 3 tandem, 14 extracranial. Nearly 71% of patients were treated with dual antiplatelet therapy and 96% were treated with high intensity statin. The RCVE rate was 23.6%. In multivariable models, borderzone infarcts were associated with increased risk of RCVE (adjusted HR 9.8 95% CI 2.1-44.8, p=0.003). The risk of RCVE was highest among internal borderzone infarcts (47.3%) as opposed to cortical borderzone infarcts (33.3%) or non borderzone infarcts (18.8%).

Conclusions: Borderzone (and particularly internal borderzone) infarcts are a surrogate marker of impaired distal blood flow and are associated with RCVE despite medical treatment. This highlights the need to develop alternate treatment strategies for this high-risk cohort.

Is There Equipoise Regarding the Optimal Medical Treatment of Patients with Asymptomatic White Matter Hyperintensities?

BACKGROUND

White matter hyperintensity (WMH) is a common manifestation of chronic ischemic microvascular disease that heralds greater risk of functional disability, stroke, and dementia. SPRINT MIND recently reported that intensive blood pressure reduction resulted in lower rates of mild cognitive impairment and WMH progression, suggesting that medical interventions could have a measurable impact on WMH. We conducted an anonymous survey of providers in the NINDS StrokeNet to better understand neurologist attitudes about asymptomatic WMH.

METHODS

We sent a 7-question survey to the 29 Regional Coordinating Centers of the StrokeNet, whose coordinators disseminated the survey to providers "involved in the care of a patient after their stroke."

RESULTS

We received 136 responses. For stroke prevention therapies, including aspirin and statin therapy and blood pressure target, there was substantial equipoise, with no single option receiving >50% endorsement and between 15-32% of respondents choosing the option of "not sure." 83% of respondents indicated high or moderate enthusiasm for a trial targeting this patient population. The clinical outcomes of reduction in ischemic stroke, cognitive impairment, or dementia were high importance (>70% endorsement), while the remaining radiographic, safety, and clinical endpoints all failed to reach 50% endorsement.

CONCLUSIONS

Our survey establishes meaningful neurologist attitudes that can inform future WMH research. There is considerable equipoise regarding optimal medical treatment for patients with asymptomatic WMH and providers in StrokeNet, who would be a vital stakeholder in WMH research in the United States, enthusiastically support a clinical trial to resolve open questions on optimal medical management.

Peri-procedural stroke or death in stenting of symptomatic severe intracranial stenosis

BACKGROUND AND PURPOSE

There are limited data on predictors of 30-day stroke or death in patients with symptomatic intracranial atherosclerosis (sICAS) undergoing stenting. We aim to determine the factors associated with stroke or death at 30 days in the stenting arm of the SAMMPRIS trial.

METHODS

This is a post-hoc analysis of the SAMMPRIS trial including patients who underwent angioplasty/stenting. We compared patient-specific variables, lesion-specific variables, procedure-specific variables, and FDA-approved indications between patients with and without the primary outcome (stroke or death at 30 days). Logistic regression analyses were performed to evaluate associations with the primary outcome.

RESULTS

We identified 213 patients, 30 of whom (14.1%) met the primary outcome. Smoking status and lesion length were associated with the primary outcome: the odds of stroke or death for non-smokers versus smokers (adjusted OR 4.46, 95% CI 1.79 to 11.1, p=0.001) and for increasing lesion length in millimeters (adjusted OR 1.20, 95% CI 1.02 to 1.39, p=0.029). These had a modest predictive value: absence of smoking history (sensitivity 66.7%, specificity 65.4%) and lesion length (area under curve 0.606). Furthermore, event rates were not significantly different between patients with and without the FDA-approved indication for stenting (15.9% vs 12%, p=0.437).

CONCLUSION

In SAMMPRIS patients who underwent angioplasty/stenting, neither clinical and neuroimaging variables nor the FDA indication for stenting reliably predicted the primary outcome. Further work in identifying reliable biomarkers of stroke/death in patients with sICAS is needed before considering new clinical trials of stenting.

TRIAL REGISTRATION NUMBER

SAMMPRIS NCT00576693; Results.

Abstract WP86: What Threshold Defines Penumbral Brain Tissue in Patients With Symptomatic Anterior Circulation Intracranial Stenosis: An Exploratory Analysis

Background: Impaired distal perfusion predicts neurological deterioration in patients with large artery atherosclerosis. We aim to determine the optimal threshold of T max delay on perfusion imaging associated with neurological deterioration in patients with symptomatic proximal anterior circulation large artery stenosis.

Methods: Data were abstracted from a prospective ischemic stroke database of consecutively enrolled patients with symptomatic proximal intracranial stenosis (internal carotid artery or M1 segment of the middle cerebral artery) who underwent magnetic resonance perfusion imaging within 24 hours of symptom onset during a 15 month period. Tissue volumes of perfusion delay T max 0-4 seconds, T max > 4 seconds, T max > 6 seconds, and T max > 8 seconds were calculated using an automated approach. A target mismatch (penumbra - core) was defined as ≥ 15 mL of brain tissue using each of the T max threshold categories. The outcome was neurological deterioration at 30 days defined as new or worsening neurological deficits that are not attributed to a non-vascular etiology.

Results: Among 52 patients with symptomatic intracranial stenosis, 26 patients met inclusion criteria. Neurological deterioration was associated with target mismatch profile defined according to T max >6 [66.7% (6/9) vs. 5.9% (1/17), p <0.01) and T max >8 [57.1% (4/7) vs. 15.8% (3/19), p = 0.05] but not T max >4 [27.3% (6/17) vs. 11.1% (1/9), p = 0.35].

Conclusion: A target mismatch profile using T max > 6 sec may optimally define tissue at risk in patients with symptomatic proximal intracranial stenosis. Larger prospective multicenter studies are needed to confirm our findings.

Is periprocedural sedation during acute stroke therapy associated with poorer functional outcomes?

BACKGROUND

To safely perform acute intra-arterial revascularization procedures, use of sedative medications and paralytics is often necessary. During the conduct of the Interventional Management of Stroke trials (I and II), the level of sedation used periprocedurally varied. At some institutions, patients were paralyzed and intubated as part of the procedural standard of care while at other institutions no routine sedation protocol was followed. The aim of this study was to identify patient characteristics that would correlate with the need for deeper sedation and to explore whether levels of sedation relate to patient outcome.

METHODS

75 of 81 patients in the Interventional Management of Stroke II Study were studied. Patients had anterior circulation strokes and underwent angiography and/or intervention. Four sedation categories were defined and tested for factors potentially associated with the level of sedation. Clinical outcomes were also analyzed, including successful angiographic reperfusion and the occurrence of clinical complications.

RESULTS

Only baseline National Institutes of Health Stroke Scale varied significantly by sedation category (p=0.01). Patients that were in the lower sedation category fared better, having a higher rate of good outcomes (p<0.01), lower death rates (p=0.02) and higher successful angiographic reperfusion rates (p=0.01). There was a significantly higher infection rate in patients receiving heavy sedation or pharmacologic paralysis (p=0.02) and a trend towards fewer groin related complications.

CONCLUSION

In this small sample, patients not receiving sedation fared better, had higher rates of successful angiographic reperfusion and had fewer complications. Further examination of the indications for procedural sedation or paralysis and their effect on outcome is warranted.

Abstract TP370: Association Between Ventricular Symmetry and Perihematoma Edema in Intracerebral Hemorrhage

Purpose: There is rising interest in the assessment of perihematoma edema (PHE) as a surrogate measure of the effectiveness of investigational therapies targeting secondary injury after intracerebral hemorrhage (ICH). However, assessment of PHE on CT scans is challenging. We hypothesized that the ratio of the volumes of the ipsilateral-to-contralateral ventricles (IL/CL) can provide an alternative estimate of PHE, and examined the association between IL/CL ventricles and semi-automated quantitative measures of PHE using non-contrast CT scans in subjects with spontaneous ICH.

Methods: We examined the volumetric imaging data from 42 subjects who participated in the HI-DEF trial. We excluded subjects who had an intraventricular hemorrhage or an EVD placed (n=21). Quantitative measurements of ICH, PHE, and ventricular volumes were performed as a routine part of the trial using ANALYZE 11.0 software. We used Spearman correlation coefficient to describe the association between IL/CL and PHE.

Results: A total of 42 CT scans were assessed (21 subjects each with both baseline and post-treatment scans, approximately 5 days later). We observed a significant correlation between PHE volume and IL/CL (r=-0.60, p<0.0001), and ICH volume + surrounding PHE (absolute PHE volume) and IL/CL (r=-0.65, p<0.0001). The correlation between relative PHE (PHE volume divided by ICH volume) and IL/CL was (r=0.50, p=0.009).

Conclusion: IL/CL seems to correlate with quantitative measures of PHE, absolute PHE volumes and, to a lesser extent, relative PHE. Ventricular symmetry might be a suitable alternative to quantitative measures of PHE on CT scans. We plan to validate the potential usefulness of IL/CL and examine its impact on long-term outcomes in the ongoing iDEF trial.

Abstract TP72: The PRISMS Trial: Baseline Characteristics of the First 100 Subjects

Introduction: Ischemic stroke patients with mild deficits were largely excluded from pivotal trials of IV rt-PA. The balance of benefit versus risk of intravenous thrombolysis for this large, understudied patient cohort is uncertain. The PRISMS trial is underway to test the benefit of IV rt-PA for treatment of mild stroke.

Objective: To characterize baseline features of the first 100 patients enrolled in this prospective cohort of exclusively mild stroke.

Methods: The PRISMS trial is a Phase 3b, double-blind, 75-center, 948-subject study evaluating IV rt-PA administered within three hours of mild stroke onset to improve 90-day functional outcome (modified Rankin Scale 0 or 1). Mild stroke is defined as NIHSS ≤5 and not “clearly disabling” (i.e., inability to return to work or perform basic activities of daily living based on current deficits). Patients are randomized 1:1 to IV rt-PA 0.9 mg/kg with aspirin placebo or IV rt-PA placebo with aspirin 325 mg. Here we describe baseline characteristics, including clinical presentations by NIHSS item, of the first 100 enrolled patients. The study team remains fully blinded to patient treatment assignment and outcomes.

Results: The 100th subject was enrolled on June 15, 2015. Baseline characteristics are presented in the Table. Median NIHSS was 2 (IQR 1-3). Clinical presentations of each patient by abnormal NIHSS items are shown in the Figure. Dysarthria, facial palsy, and sensory loss were the most common deficits.

Conclusions: This initial 100-patient PRISMS cohort is consistent with expectations. Upon completion, the PRISMS trial will determine the benefit of IV rt-PA for mild stroke.

Abstract 53: Multimodal CT Imaging: Time to Treatment and Outcomes in the Interventional Management of Stroke (IMS) III Trial

Introduction: The importance of time in acute stroke is well established. Using the Interventional Management of Stroke (IMS) III trial data, we explored the effect of imaging on time to treatment and outcomes for subjects those receiving multimodal imaging [CT angiogram (CTA) + CT perfusion (CTP) versus CTA alone] versus those who did not.

Materials and Methods: Multimodal CT was not a prerequisite for IMS III entry .We examined 3 subgroups; those with baseline CTA alone, CTA + CTP, versus those with no CTA or CTP. The baseline demographics and imaging and treatment time parameters of these 3 subgroups were studied.

Results: Of the 656 subjects enrolled, 98 (14.9%) underwent baseline (pre-IV t-PA treatment) CTA+CTP. 8 out of these 98 patients received only CTP. 216 (32.9%) received CTA alone and 342 (52.1%) had neither.

Time parameters for the CTA+CTP, CTA alone, and no CTA/CTP groups were as follows: median from stroke onset to IV t-PA (120.5 vs. 117.5 vs 120 min; p=0.5869), median IV t-PA bolus to groin puncture (GP) (78 vs. 81 vs. 91 min; p=0.0043) and median GP to start of endovascular therapy (EVT) (31 vs. 38 vs. 44 min; p=0.0001). Pairwise comparison demonstrated no significant difference in time from IV tPA to GP and time from GP to IA therapy between CTA+CTP and CTA alone groups (p=0. 9883 and p=0.1421, respectively). With removal of drip n’ ship subjects, no statistical differences were seen between groups for time from onset to IV t-PA bolus (p=0.5509) or time from imaging to GP (p=0.8459). Time from GP to start of EVT was still shorter in the CTA+CTP and CTA alone paradigms (p =0.0019).

In the IV t-PA treatment arm, no differences in 90d mRS 0-2 outcome were seen in the 3 subgroups (36.4% versus 40.9% versus 38.2%; p=0.8941). In the EVT arm, differences in good outcome were seen (38.5% versus 52.0% versus 33.8%; p=0.0020). CTA alone remained strongly associated with good outcomes in EVT arm (adjusted OR, 2.117; 95% CI, 1.35- 3.30), irrespective of age, stroke severity and time from onset to IV tPA initiation.

Conclusion: Multimodal imaging did not delay treatment times in IMS III. The CTA alone group was associated with favorable clinical outcomes in the endovascular arm. The CTA+CTP paradigm resulted in worse outcome over the CTA alone paradigm in the endovascular arm.

Abstract 143: Evaluation of Interval Times from Onset to Recanalization in Patients Undergoing Endovascular Therapy in the IMS III Trial

Background: There were significant delays in achieving recanalization observed in the IA arm of IMS III. A detailed analysis of the workflow helps to identify factors contributing to overall delay.

Methods: In 418 subjects randomized to the IA arm, the following time intervals were calculated: stroke onset to ED arrival; ED to CT; CT to start of IV tPA; IV tPA to randomization; randomization to groin puncture; groin puncture to thrombus identification; thrombus identification to start of IA therapy; start of IA therapy to reperfusion. The effects of time of day and general anesthesia (GA) on workflow were evaluated. The change of ED to reperfusion and groin puncture to reperfusion over the study period were also evaluated. All times are reported as medians (with IQR).Kruskal-Wallis test was applied.

Results: Time intervals are shown in figure 1. Intubation had no significant effect on the overall workflow time. The time from CT to groin puncture during business hours (Mon-Fri; 0800-1700) was 119 min (n=201; IQR 49 min) and after hours was 141 min (n=203; IQR 54 min, p <0.0001). The time from CT to groin puncture during day time (0800-2100) was 127 min (n=341; IQR: 51 min) and during night time was 142 min (n=63; IQR 60 min, p=0.0012). After adjusting for multiple comparisons (Bonferroni method), the times from ED to reperfusion (316 min in 1st quartile to 246 min in last quartile,p<0.0001), and groin puncture to reperfusion (145 min in 1st quartile to 120 min in last quartile;p=0.0005) decreased over the trial duration.

Conclusion: In the endovascular arm of the IMS III trial there were significant delays from start of IV tPA to groin puncture. Endovascular techniques used in the trial were quite inefficient in achieving recanalization. Use of GA did not result in additional delays. Endovascular treatment outside of daytime hours did result in slight additional delays. These data may help in designing, optimizing and documenting workflow in current and future endovascular trials.

Abstract W P4: Time to Angiographic Reperfusion: A Decision Analysis

Introduction: The Interventional Management of Stroke (IMS) III trial found no significant difference in outcomes between the combined intravenous (IV) t-PA/endovascular and IV t-PA groups. A suggested reason for lack of IV/IA effect is that good clinical outcome following angiographic reperfusion is strongly time dependent; this was shown in IMS I/II and validated in IMS III. Using decision modeling we addressed the following question: How quickly should reperfusion with IA therapy be achieved to demonstrate superiority of IV/IA therapy versus IV t-PA alone?

Methods: We developed a decision analytic model using IMS III trial data and comprehensive literature review. Base case: large vessel occlusion, IV t-PA within 3 hours, time from stroke onset to reperfusion 325 min, reperfusion rate with IA therapy 0.76, probability of good outcome after IA reperfusion 0.40, probability of good outcome after no IA reperfusion 0.10. IV t-PA rates of good outcome were based on subset of IMS III subjects with large vessel occlusion on baseline CTA. Utilities were assigned to mRS outcome levels based on previously published data.

Results: The IV t-PA alone approach yielded expected utility of 1.26 quality-adjusted life years (QALYs) compared to 1.08 QALYs for the IV/IA approach. One-way sensitivity analyses for time to reperfusion demonstrated superiority of IV t-PA alone above a reperfusion time of 273 minutes. IV/IA approach could be superior if reperfusion times were shorter.

Conclusion: If mean reperfusion time can be reduced to ≤ 273 minutes our analysis suggests that IV/IA therapy could be superior to IV t-PA alone using the IMS III revascularization approaches given the original sample size of IMS III. Further analyses will be included in the abstract presentation, by which time the IMS III database will be closed and additional relevant data available to investigators. We then will be able to more accurately estimate the various time components modeled, including: time from onset to IV start, IV start to groin puncture, groin puncture to IA start and time from IA start to IA end, as well as the impact of reperfusion delay and reperfusion rates on clinical outcomes along with probabilistic sensitivity analyses.

Abstract 7: Differential Effect of Baseline Cta Collateral Status on Clinical Outcomes in Patients Enrolled in the Ims-3 Trial

Introduction: In the IMS 3 trial, we test the hypothesis that a differential effect of endovascular therapy on clinical outcome will be most apparent in patients with severely ischemic but salvageable brain tissue (moderate collaterals on baseline CTA).

Methods: Data is from patients in the IMS 3 study. Of 656 patients in the study, 306 patients had baseline CTA and 204 patients had M1 MCA +/_ intracranial ICA occlusion where baseline collaterals could be measured. Collateral status was assessed by consensus using 3 different scores and categorized as good, intermediate and poor. Details of the IMS 3 study protocol are described in the primary paper.

Results: Of 204 patients, 138 received endovascular therapy (85.7% recanalized, 44.2% achieved 90-day mRS 0-2) and 66 received IV tPA only (57.1% recanalized, 36.4% achieved 90-day mRS 0-2). Proportion of patients with 90-day mRS 0-2 in good, intermediate and poor collateral categories between endovascular therapy and IV tPA across the 3 scores were: score 1(good: 56.5% vs. 41.7%, intermediate: 45.2% vs. 22.2%, poor: 18.4% vs. 23.5%); score 2 (good: 57.4% vs. 42.3%, intermediate: 40% vs. 23.1%, poor: 5.3% vs. 14.3%); score 3 (good: 51.6% vs. 42.3%, intermediate: 43.3% vs. 23.5%, poor: 20.6% vs. 18.8%). Using the van-Elteren test, a significant shift in 90-day mRS distribution in favor of endovascular therapy was noted only for subjects with intermediate collaterals. (p=0.01 for scores 1 and 2, Figure 1) Clinical outcome was poor with no differential effect of therapy in patients with poor collaterals.

Conclusion: Patients with baseline intermediate collaterals have the highest likelihood of showing better clinical response to endovascular therapy. Future clinical trials testing IV tPA vs. endovascular therapy may have a higher likelihood of showing differential treatment effect if patients with baseline poor collaterals are excluded.

Abstract TP49: Association Between Low CBV and ICH in Acute Stroke Patients Undergoing Intra-Arterial Therapy

Background: Acute stroke patients with middle cerebral artery (MCA) or intracranial internal carotid artery (ICA) occlusion who have decreased cerebral blood volume (CBV) in the basal ganglia (BG) on CT perfusion (CTP) imaging are thought to be at high risk of intracerebral hemorrhage (ICH) following recanalization with intra-arterial therapy (IAT). We sought to determine if low BG CBV in patients with MCA or ICA occlusion is associated with post-IAT ICH.

Methods: This is a single-center retrospective chart review of consecutive stroke patients seen in the emergency room from 6/07 - 12/10. All acute stroke patients with an MCA (M1) or intracranial ICA occlusion on CT angiogram, who underwent CTP imaging and were treated with IAT (IA tpa and/or thrombectomy) were included. The primary outcome was the presence of ICH on CT 24 hours post-IAT. Good clinical outcome was defined as a modified Rankin score ≤ 3 at discharge. Clinical variables, CBV, and ICH were each assessed by investigators who were blinded to the other abstracted data. CBV and ICH were agreed upon by at least 2 readers. Univariate analyses were performed using chi-square tests. Multivariate analyses of other potential predictors of ICH were done using logistic regression.

Results: Sixty-two patients were included in these analyses. The mean age was 65.8 years, 44% were male, and 34% were non-white. The mean time to artery recanalization was 717 minutes. In univariate analysis, there was a trend toward higher rates of post-IAT ICH in patients with low BG CBV compared to those with preserved CBV (64.3% vs. 47.1%, p=0.175). Patients with post-IAT ICH had higher rates of a poor outcome than those without ICH (94.1% vs 64.3%, p=0.0031). Multivariate analyses did not demonstrate any independent predictors of ICH.

Conclusion: Acute stroke patients with proximal MCA or ICA occlusion and low BG CBV on CTP imaging had a trend toward a higher risk of post-IAT ICH, but this association was not statistically significant, possibly due to the small sample size. Given that ICH is associated with poor outcome, future studies are needed to determine if patients with low BG CBV should be excluded from IAT due to increased risk of ICH. .

Abstract WP5: Collaterals in the Interventional Management of Stroke (IMS) III Trial

Background: Collateral circulation may exert an influential effect on arterial recanalization, downstream angiographic and tissue reperfusion and ensuing clinical outcomes after revascularization for acute ischemic stroke. Endovascular strategies provide unique opportunity to correlate definitive angiographic measures of collaterals at the time of interventional therapy. We conducted a systematic analysis of collaterals on conventional angiography in the endovascular treatment arm of the Interventional Management of Stroke (IMS) III trial.

Methods: Prospective evaluation of angiographic collaterals was conducted via central review of all cases enrolled and treated in the endovascular arm of IMS III. Collateral grade was assessed with the ASITN/SIR scale on angiography at procedure start and immediately prior to intra-arterial treatment (time 0), blind to all other data. Statistical analyses investigated the association between collateral grade with baseline clinical data, angiographic measures of recanalization (AOL), angiographic reperfusion (TICI), and clinical outcomes.

Results: From 2006-2012, 380 cases were prospectively evaluated for collateral grade at start of procedure and time 0 prior to treatment. Adequate collateral views were available in 283/380 (75%) cases at baseline, and 277/380 (73%) cases at time 0 and after subsequent treatment with intra-arterial tPA, EKOS, MERCI, Penumbra, and Solitaire devices. Detailed results will be presented at ISC in coordination with release of the primary trial results. The relationships between collateral flow grade and baseline clinical features (NIHSS and age), location of vascular occlusion at cerebral angiography, AOL recanalization and TICI reperfusion, and mROS of 0-2 at 90 days will be presented. Analyses will explore potential interactions between collateral flow grade with recanalization, angiographic reperfusion, and clinical outcome.

Conclusions: Collateral circulation was available and prospectively evaluated in the largest endovascular therapy trial for stroke conducted to date. The role of collaterals may be an important consideration in the design of future endovascular trials.

Abstract 3192: A Descriptive Study of Interventional Management of Stroke III Trial Investigator Recruitment Enhancement Strategies

Purpose: Randomized control trials (RCT) are the gold standard of clinical research, yet most RCTs do not finish on time or on budget of the original proposal. The literature lacks research relevant to enhancing investigator recruitment strategies. Therefore, we sought to explore the role of these strategies in the ongoing NIH-funded, Interventional Management of Stroke (IMS) Phase III Trial.

Method: We limited this analysis to November 1, 2007 - July 31, 2011 to exclude the start-up period for the trial. We compiled the dates of all potential recruitment enhancing strategies used in the trial, including investigator meetings, contests to reward recruitment, amendments to broaden eligibility criteria, and the addition of more sites in the US and internationally. We compared mean enrollment in the two months immediately before and after the month of intervention, and prespecified that an enrollment change of ≥ 25% would be considered a potentially effective recruitment strategy. Given the limited variability, only descriptive analyses were performed.

Results: From November 2007 through July 2011, the mean monthly recruitment in the IMS III Trial was 9.77, ( SD = 3.2) subjects and the range was 4-20. There was no significant change in recruitment rates over time ( p = 0.56). We identified a change of ≥ 25% after each investigators’ meeting at the International Stroke Conference in 2008, 2009, 2010, and 2011. Other interventions that exceeded the 25% change were the submission of Amendment 3 (Jan 2009), conduct of an investigators’ conference call (Aug 2010), and initiation of screening at European sites (Mar 2011). See Table 1.

Discussion: Investigators’ meetings and/or the International Stroke Conference appeared to increase enrollment significantly in the IMS III Trial. We speculate that these investigators’ meetings convey the commitment of the PI and administrative staff and increase the enthusiasm of investigators to complete the study. Additional efforts may have been beneficial, but our analysis was limited by multiple confounding factors, including the imprecision of the timing for implementation of some strategies as with IRB-approval of new amendments at each institution, and individual site factors such as the probation of underachieving sites. Review of the literature identified online education pertaining to consent methodology as a new avenue for the IMS III Trial to explore to maintain recruitment. Further evidence-based study of methods to improve investigator-initiated recruitment is needed. Table 1: Recruitment Efforts and Corresponding Monthly Enrollment Rates

Safety and tolerability of deferoxamine mesylate in patients with acute intracerebral hemorrhage

BACKGROUND AND PURPOSE

Treatment with the iron chelator, deferoxamine mesylate (DFO), improves neurological recovery in animal models of intracerebral hemorrhage (ICH). We aimed to evaluate the feasibility, safety, and tolerability of varying dose-tiers of DFO in patients with spontaneous ICH, and to determine the maximum tolerated dose to be adopted in future efficacy studies.

METHODS

This was a multicenter, phase-I, dose-finding study using the Continual Reassessment Method. DFO was administered by intravenous infusion for 3 consecutive days, starting within 18 hours of ICH onset. Subjects underwent repeated clinical assessments through 90 days, and computed tomography neuroimaging pre- and post-drug-administration.

RESULTS

Twenty subjects were enrolled onto 5 dose tiers, starting with 7 mg/kg per day and ending with 62 mg/kg per day as the maximum tolerated dose. Median age was 68 years (range, 50-90); 60% were men; and median Glasgow Coma Scale and National Institutes of Health Stroke Scale scores on admission were 15 (5-15) and 9 (0-39), respectively. ICH location was lobar in 40%, deep in 50%, and brain stem in 10%; intraventricular hemorrhage was present in 15%. DFO was discontinued because of adverse events in 2 subjects (10%). Six subjects (30%) experienced 12 serious adverse events, none of which were drug-related. DFO infusions were associated with mild blood-pressure-lowering effects. Fifty percent of patients had modified Rankin scale scores ≤2, and 39% had modified Rankin scale scores of 4 to 6 on day 90; 15% died.

CONCLUSIONS

Consecutive daily infusions of DFO after ICH are feasible, well-tolerated, and not associated with excessive serious adverse events or mortality. Our findings lay the groundwork for future studies to evaluate the efficacy of DFO in ICH.

Is periprocedural sedation during acute stroke therapy associated with poorer functional outcomes?

BACKGROUND

To safely perform acute intra-arterial revascularization procedures, use of sedative medications and paralytics is often necessary. During the conduct of the Interventional Management of Stroke trials (I and II), the level of sedation used periprocedurally varied. At some institutions, patients were paralyzed and intubated as part of the procedural standard of care while at other institutions no routine sedation protocol was followed. The aim of this study was to identify patient characteristics that would correlate with the need for deeper sedation and to explore whether levels of sedation relate to patient outcome.

METHODS

75 of 81 patients in the Interventional Management of Stroke II Study were studied. Patients had anterior circulation strokes and underwent angiography and/or intervention. Four sedation categories were defined and tested for factors potentially associated with the level of sedation. Clinical outcomes were also analyzed, including successful angiographic reperfusion and the occurrence of clinical complications.

RESULTS

Only baseline National Institutes of Health Stroke Scale varied significantly by sedation category (p=0.01). Patients that were in the lower sedation category fared better, having a higher rate of good outcomes (p<0.01), lower death rates (p=0.02) and higher successful angiographic reperfusion rates (p=0.01). There was a significantly higher infection rate in patients receiving heavy sedation or pharmacologic paralysis (p=0.02) and a trend towards fewer groin related complications.

CONCLUSION

In this small sample, patients not receiving sedation fared better, had higher rates of successful angiographic reperfusion and had fewer complications. Further examination of the indications for procedural sedation or paralysis and their effect on outcome is warranted.