Contemporary management of aneurysmal subarachnoid haemorrhage. An update for the intensivist.

Aneurysmal subarachnoid haemorrhage (aSAH) is a rare yet profoundly debilitating condition associated with high global case fatality and morbidity rates. The key determinants of functional outcome include early brain injury, rebleeding of the ruptured aneurysm and delayed cerebral ischaemia. The only effective way to reduce the risk of rebleeding is to secure the ruptured aneurysm quickly. Prompt diagnosis, transfer to specialized centers, and meticulous management in the intensive care unit (ICU) significantly improved the prognosis of aSAH. Recently, multimodality monitoring with specific interventions to correct pathophysiological imbalances has been proposed. Vigilance extends beyond intracranial concerns to encompass systemic respiratory and haemodynamic monitoring, as derangements in these systems can precipitate secondary brain damage. Challenges persist in treating aSAH patients, exacerbated by a paucity of robust clinical evidence, with many interventions showing no benefit when tested in rigorous clinical trials. Given the growing body of literature in this field and the issuance of contemporary guidelines, our objective is to furnish an updated review of essential principles of ICU management for this patient population. Our review will discuss the epidemiology, initial stabilization, treatment strategies, long-term prognostic factors, the identification and management of post-aSAH complications. We aim to offer practical clinical guidance to intensivists, grounded in current evidence and expert clinical experience, while adhering to a concise format.

Optimal Design of Clinical Trials Involving Persons with Disorders of Consciousness.

BACKGROUND: Limited data exist regarding the optimal clinical trial design for studies involving persons with disorders of consciousness (DoC), and only a few therapies have been tested in high-quality clinical trials. To address this, the Curing Coma Campaign Clinical Trial Working Group performed a gap analysis on the current state of clinical trials in DoC to identify the optimal clinical design for studies involving persons with DoC. METHODS: The Curing Coma Campaign Clinical Trial Working Group was divided into three subgroups to (1) review clinical trials involving persons with DoC, (2) identify unique challenges in the design of clinical trials involving persons with DoC, and (3) recommend optimal clinical trial designs for DoC. RESULTS: There were 3055 studies screened, and 66 were included in this review. Several knowledge gaps and unique challenges were identified. There is a lack of high-quality clinical trials, and most data regarding patients with DoC are based on observational studies focusing on patients with traumatic brain injury and cardiac arrest. There is a lack of a structured long-term outcome assessment with significant heterogeneity in the methodology, definitions of outcomes, and conduct of studies, especially for long-term follow-up. Another major barrier to conducting clinical trials is the lack of resources, especially in low-income countries. Based on the available data, we recommend incorporating trial designs that use master protocols, sequential multiple assessment randomized trials, and comparative effectiveness research. Adaptive platform trials using a multiarm, multistage approach offer substantial advantages and should make use of biomarkers to assess treatment responses to increase trial efficiency. Finally, sound infrastructure and international collaboration are essential to facilitate the conduct of trials in patients with DoC. CONCLUSIONS: Conduct of trials in patients with DoC should make use of master protocols and adaptive design and establish international registries incorporating standardized assessment tools. This will allow the establishment of evidence-based practice recommendations and decrease variations in care.

Computational modelling in disorders of consciousness: Closing the gap towards personalised models for restoring consciousness.

Disorders of consciousness are complex conditions characterised by persistent loss of responsiveness due to brain injury. They present diagnostic challenges and limited options for treatment, and highlight the urgent need for a more thorough understanding of how human consciousness arises from coordinated neural activity. The increasing availability of multimodal neuroimaging data has given rise to a wide range of clinically- and scientifically-motivated modelling efforts, seeking to improve data-driven stratification of patients, to identify causal mechanisms for patient pathophysiology and loss of consciousness more broadly, and to develop simulations as a means of testing in silico potential treatment avenues to restore consciousness. As a dedicated Working Group of clinicians and neuroscientists of the international Curing Coma Campaign, here we provide our framework and vision to understand the diverse statistical and generative computational modelling approaches that are being employed in this fast-growing field. We identify the gaps that exist between the current state-of-the-art in statistical and biophysical computational modelling in human neuroscience, and the aspirational goal of a mature field of modelling disorders of consciousness; which might drive improved treatments and outcomes in the clinic. Finally, we make several recommendations for how the field as a whole can work together to address these challenges.

Hypothermia for Patients Requiring Evacuation of Subdural Hematoma: A Multicenter Randomized Clinical Trial.

BACKGROUND: Hypothermia is neuroprotective in some ischemia-reperfusion injuries. Ischemia-reperfusion injury may occur with traumatic subdural hematoma (SDH). This study aimed to determine whether early induction and maintenance of hypothermia in patients with acute SDH would lead to decreased ischemia-reperfusion injury and improve global neurologic outcome. METHODS: This international, multicenter randomized controlled trial enrolled adult patients with SDH requiring evacuation of hematoma within 6 h of injury. The intervention was controlled temperature management of hypothermia to 35 °C prior to dura opening followed by 33 °C for 48 h compared with normothermia (37 °C). Investigators randomly assigned patients at a 1:1 ratio between hypothermia and normothermia. Blinded evaluators assessed outcome using a 6-month Glasgow Outcome Scale Extended score. Investigators measured circulating glial fibrillary acidic protein and ubiquitin C-terminal hydrolase L1 levels. RESULTS: Independent statisticians performed an interim analysis of 31 patients to assess the predictive probability of success and the Data and Safety Monitoring Board recommended the early termination of the study because of futility. Thirty-two patients, 16 per arm, were analyzed. Favorable 6-month Glasgow Outcome Scale Extended outcomes were not statistically significantly different between hypothermia vs. normothermia groups (6 of 16, 38% vs. 4 of 16, 25%; odds ratio 1.8 [95% confidence interval 0.39 to ∞], p = .35). Plasma levels of glial fibrillary acidic protein (p = .036), but not ubiquitin C-terminal hydrolase L1 (p = .26), were lower in the patients with favorable outcome compared with those with unfavorable outcome, but differences were not identified by temperature group. Adverse events were similar between groups. CONCLUSIONS: This trial of hypothermia after acute SDH evacuation was terminated because of a low predictive probability of meeting the study objectives. There was no statistically significant difference in functional outcome identified between temperature groups.

Proceedings of the First Curing Coma Campaign NIH Symposium: Challenging the Future of Research for Coma and Disorders of Consciousness.

Coma and disorders of consciousness (DoC) are highly prevalent and constitute a burden for patients, families, and society worldwide. As part of the Curing Coma Campaign, the Neurocritical Care Society partnered with the National Institutes of Health to organize a symposium bringing together experts from all over the world to develop research targets for DoC. The conference was structured along six domains: (1) defining endotype/phenotypes, (2) biomarkers, (3) proof-of-concept clinical trials, (4) neuroprognostication, (5) long-term recovery, and (6) large datasets. This proceedings paper presents actionable research targets based on the presentations and discussions that occurred at the conference. We summarize the background, main research gaps, overall goals, the panel discussion of the approach, limitations and challenges, and deliverables that were identified.

A Precision Medicine Framework for Classifying Patients with Disorders of Consciousness: Advanced Classification of Consciousness Endotypes (ACCESS).

BACKGROUND: Consciousness in patients with brain injury is traditionally assessed based on semiological evaluation at the bedside. This classification is limited because of low granularity, ill-defined and rigid nomenclatures incompatible with the highly fluctuating nature of consciousness, failure to identify specific brain states like cognitive motor dissociation, and neglect for underlying biological mechanisms. Here, the authors present a pragmatic framework based on consciousness endotypes that combines clinical phenomenology with all essential physiological and biological data, emphasizing recovery trajectories, therapeutic potentials and clinical feasibility. METHODS: The Neurocritical Care Society's Curing Coma Campaign identified an international group of experts who convened in a series of online meetings between May and November 2020 to discuss and propose a novel framework for classifying consciousness. RESULTS: The expert group proposes Advanced Classification of Consciousness Endotypes (ACCESS), a tiered multidimensional framework reflecting increasing complexity and an aspiration to consider emerging and future approaches. Tier 1 is based on clinical phenotypes and structural imaging. Tier 2 adds functional measures including EEG, PET and functional MRI, that can be summarized using the Arousal, Volition, Cognition and Mechanisms (AVCM) score (where "Volition" signifies volitional motor responses). Finally, Tier 3 reflects dynamic changes over time with a (theoretically infinite) number of physiologically distinct states to outline consciousness recovery and identify opportunities for therapeutic interventions. CONCLUSIONS: Whereas Tiers 1 and 2 propose an approach for low-resource settings and state-of-the-art expertise at leading academic centers, respectively, Tier 3 is a visionary multidimensional consciousness paradigm driven by continuous incorporation of new knowledge while addressing the Curing Coma Campaign's aspirational goals.

Mechanisms Underlying Disorders of Consciousness: Bridging Gaps to Move Toward an Integrated Translational Science.

AIM: In order to successfully detect, classify, prognosticate, and develop targeted therapies for patients with disorders of consciousness (DOC), it is crucial to improve our mechanistic understanding of how severe brain injuries result in these disorders. METHODS: To address this need, the Curing Coma Campaign convened a Mechanisms Sub-Group of the Coma Science Work Group (CSWG), aiming to identify the most pressing knowledge gaps and the most promising approaches to bridge them. RESULTS: We identified a key conceptual gap in the need to differentiate the neural mechanisms of consciousness per se, from those underpinning connectedness to the environment and behavioral responsiveness. Further, we characterised three fundamental gaps in DOC research: (1) a lack of mechanistic integration between structural brain damage and abnormal brain function in DOC; (2) a lack of translational bridges between micro- and macro-scale neural phenomena; and (3) an incomplete exploration of possible synergies between data-driven and theory-driven approaches. CONCLUSION: In this white paper, we discuss research priorities that would enable us to begin to close these knowledge gaps. We propose that a fundamental step towards this goal will be to combine translational, multi-scale, and multimodal data, with new biomarkers, theory-driven approaches, and computational models, to produce an integrated account of neural mechanisms in DOC. Importantly, we envision that reciprocal interaction between domains will establish a "virtuous cycle," leading towards a critical vantage point of integrated knowledge that will enable the advancement of the scientific understanding of DOC and consequently, an improvement of clinical practice.

Phase 1b Study to Evaluate Safety, Tolerability, and Maximum Tolerated Dose of PF-05230907 for Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: This study aimed to determine the maximum tolerated dose and to evaluate the overall safety and tolerability of single doses of PF-05230907 in subjects with acute intracerebral hemorrhage. METHODS: Individuals presenting with intracerebral hemorrhage were enrolled in a phase 1, multicenter, open-label clinical trial. A Bayesian modified continual reassessment method design based on treatment-emergent thromboembolic or ischemic events was adopted. Sequential dosing, an external data monitoring committee, and prespecified stopping rules were incorporated as safeguards. RESULTS: Twenty-one subjects received PF-05230907. The mean (±SD) age in years and intracerebral hemorrhage volume in mL at baseline were 62 (±9) and 18 (±11), respectively. Two treatment-emergent thromboembolic or ischemic events occurred (deep vein thrombosis and cerebral ischemia), in the 30 µg/kg dose group. There were no other clear drug-related toxicities at dose levels ranging from 5 to 30 µg/kg. At the time of study termination, the maximum tolerated dose was estimated to be 24 µg/kg, with a mean fitted dose-toxicity estimate of 11.9% (95% CI, 1.2%-27.4%). CONCLUSIONS: Single doses of PF-05230907 appeared to be tolerated across a range of doses in the intracerebral hemorrhage population, with thrombotic events observed only at the highest dose level tested. Recruitment within the recommended therapeutic window of opportunity remains a challenge. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02687191.

NEWTON-2 Cisternal (Nimodipine Microparticles to Enhance Recovery While Reducing Toxicity After Subarachnoid Hemorrhage): A Phase 2, Multicenter, Randomized, Open-Label Safety Study of Intracisternal EG-1962 in Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: A sustained release microparticle formulation of nimodipine (EG-1962) was developed for treatment of patients with aneurysmal subarachnoid hemorrhage (aSAH). OBJECTIVE: To assess safety, tolerability, and pharmacokinetics of intracisternal EG-1962 in an open-label, randomized, phase 2 study of up to 12 subjects. METHODS: Subjects were World Federation of Neurological Surgeons grades 1 to 2, modified Fisher grades 2 to 4, and underwent aneurysm clipping within 48 h of aSAH. EG-1962, containing 600 mg nimodipine, was administered into the basal cisterns. Outcome on the extended Glasgow Outcome Scale (eGOS), pharmacokinetics, delayed cerebral ischemia and infarction, rescue therapy, and safety were evaluated. RESULTS: The study was halted when a phase 3 study of intraventricular EG-1962 stopped because that study was unlikely to meet its primary endpoint. Six subjects were randomized (5 EG-1962 and 1 oral nimodipine). After 90-d follow-up, favorable outcome on the eGOS occurred in 1 of 5 EG-1962 and in the single oral nimodipine patient. Four EG-1962 and the oral nimodipine subject had angiographic vasospasm. One EG-1962 subject had delayed cerebral ischemia, and all subjects with angiographic vasospasm received rescue therapy except 1 EG-1962 patient. One subject treated with EG-1962 developed right internal carotid and middle cerebral artery narrowing 5 mo after placement of EG-1962, leading to occlusion and cerebral infarction. Pharmacokinetics showed similar plasma concentrations of nimodipine in both groups. CONCLUSION: Angiographic vasospasm and unfavorable clinical outcome still occurred after placement of EG-1962. Internal carotid artery narrowing and occlusion after placement of EG-1962 in the basal cisterns has not been reported.

The Curing Coma Campaign: Framing Initial Scientific Challenges-Proceedings of the First Curing Coma Campaign Scientific Advisory Council Meeting.

Coma and disordered consciousness are common manifestations of acute neurological conditions and are among the most pervasive and challenging aspects of treatment in neurocritical care. Gaps exist in patient assessment, outcome prognostication, and treatment directed specifically at improving consciousness and cognitive recovery. In 2019, the Neurocritical Care Society (NCS) launched the Curing Coma Campaign in order to address the "grand challenge" of improving the management of patients with coma and decreased consciousness. One of the first steps was to bring together a Scientific Advisory Council including coma scientists, neurointensivists, neurorehabilitationists, and implementation experts in order to address the current scientific landscape and begin to develop a framework on how to move forward. This manuscript describes the proceedings of the first Curing Coma Campaign Scientific Advisory Council meeting which occurred in conjunction with the NCS Annual Meeting in October 2019 in Vancouver. Specifically, three major pillars were identified which should be considered: endotyping of coma and disorders of consciousness, biomarkers, and proof-of-concept clinical trials. Each is summarized with regard to current approach, benefits to the patient, family, and clinicians, and next steps. Integration of these three pillars will be essential to the success of the Curing Coma Campaign as will expanding the "curing coma community" to ensure broad participation of clinicians, scientists, and patient advocates with the goal of identifying and implementing treatments to fundamentally improve the outcome of patients.

Single-Dose Intraventricular Nimodipine Microparticles Versus Oral Nimodipine for Aneurysmal Subarachnoid Hemorrhage.

Background and Purpose- EG-1962 is a sustained release formulation of nimodipine administered via external ventricular drain in patients with aneurysmal subarachnoid hemorrhage. A randomized, open-label, phase 1/2a, dose-escalation study provided impetus for this study to evaluate efficacy and safety of a single intraventricular 600 mg dose of EG-1962 to patients with aneurysmal subarachnoid hemorrhage, compared with standard of care oral nimodipine. Methods- Subjects were World Federation of Neurological Surgeons grades 2-4, modified Fisher grades 2-4 and had an external ventricular drain inserted as part of standard of care. The primary end point was the proportion of subjects with favorable outcome at day 90 after aneurysmal subarachnoid hemorrhage (extended Glasgow outcome scale 6-8). The proportion of subjects with favorable outcome at day 90 on the Montreal cognitive assessment, as well as the incidence of delayed cerebral ischemia and infarction, use of rescue therapy and safety were evaluated. Results- The study was halted by the independent data monitoring board after planned interim analysis of 210 subjects (289 randomized) with day 90 outcome found the study was unlikely to achieve its primary end point. After day 90 follow-up of all subjects, the proportion with favorable outcome on the extended Glasgow outcome scale was 45% (65/144) in the EG-1962 and 42% (62/145) in the placebo group (risk ratio, 1.01 [95% CI, 0.83-1.22], P=0.95). Consistent with its mechanism of action, EG-1962 significantly reduced vasospasm (50% [69/138] EG-1962 versus 63% [91/144], P=0.025) and hypotension (7% [9/138] versus 10% [14/144]). Analysis of prespecified subject strata suggested potential efficacy in World Federation of Neurological Surgeons 3-4 subjects (46% [32/69] EG-1962 versus 32% [24/75] placebo, odds ratio, 1.22 [95% CI, 0.94-1.58], P=0.13). No safety concerns were identified that halted the study or that preclude further development. Conclusions- There was no significant increase in favorable outcome for EG-1962 compared with standard of care in the overall study population. The safety profile was acceptable. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02790632.

Nimodipine pharmacokinetics after intraventricular injection of sustained-release nimodipine for subarachnoid hemorrhage.

OBJECTIVE: The objective of this study was to measure the concentration of nimodipine in CSF and plasma after intraventricular injection of a sustained-release formulation of nimodipine (EG-1962) in patients with aneurysmal subarachnoid hemorrhage (SAH). METHODS: Patients with SAH repaired by clip placement or coil embolization were randomized to EG-1962 or oral nimodipine. Patients were classified as grade 2-4 on the World Federation of Neurosurgical Societies grading scale for SAH and had an external ventricular drain inserted as part of their standard of care. Cohorts of 12 patients received 100-1200 mg of EG-1962 as a single intraventricular injection (9 per cohort) or they remained on oral nimodipine (3 per cohort). Plasma and CSF were collected from each patient for measurement of nimodipine concentrations and calculation of maximum plasma and CSF concentration, area under the concentration-time curve from day 0 to 14, and steady-state concentration. RESULTS: Fifty-four patients in North America were randomized to EG-1962 and 18 to oral nimodipine. Plasma concentrations increased with escalating doses of EG-1962, remained stable for 14 to 21 days, and were detectable at day 30. Plasma concentrations in the oral nimodipine group were more variable than for EG-1962 and were approximately equal to those occurring at the EG-1962 800-mg dose. CSF concentrations of nimodipine in the EG-1962 groups were 2-3 orders of magnitude higher than in the oral nimodipine group, in which nimodipine was only detected at low concentrations in 10% (21/213) of samples. In the EG-1962 groups, CSF nimodipine concentrations were 1000 times higher than plasma concentrations. CONCLUSIONS: Plasma concentrations of nimodipine similar to those achieved with oral nimodipine and lasting for 21 days could be achieved after a single intraventricular injection of EG-1962. The CSF concentrations from EG-1962, however, were at least 2 orders of magnitude higher than those with oral nimodipine. These results supported a phase 3 study that demonstrated a favorable safety profile for EG-1962 but yielded inconclusive efficacy results due to notable differences in clinical outcome based on baseline disease severity.Clinical trial registration no.: NCT01893190 (ClinicalTrials.gov).

Burden of cerebral hypoperfusion in patients with delayed cerebral ischemia after subarachnoid hemorrhage.

OBJECTIVE: Delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) may result in focal neurological deficits and cerebral infarction, believed to result from critical regional rather than global impairments in cerebral blood flow (CBF). However, the burden of such regional hypoperfusion has not been evaluated by gold-standard voxel-by-voxel CBF measurements. Specifically, the authors sought to determine whether the proportion of brain affected by hypoperfusion was greater in patients with DCI than in SAH controls without DCI and whether the symptomatic hemisphere (in those with lateralizing deficits) exhibited a greater cerebral hypoperfusion burden. METHODS: Sixty-one patients with aneurysmal SAH underwent 15O PET to measure regional CBF during the period of risk for DCI (median 8 days after SAH, IQR 7-10 days). Regions of visibly abnormal brain on head CT studies, including areas of hemorrhage and infarction, were excluded. Burden of hypoperfusion was defined as the proportion of PET voxels in normal-appearing brain with CBF < 25 ml/100 g/min. Global CBF and hypoperfusion burden were compared between patients with and those without DCI at the time of PET. For patients with focal impairments from DCI, the authors also compared average CBF and hypoperfusion burden in symptomatic versus asymptomatic hemispheres. RESULTS: Twenty-three patients (38%) had clinical DCI at the time of PET. Those with DCI had higher mean arterial pressure (MAP; 126 ± 14 vs 106 ± 12 mm Hg, p < 0.001) and 18 (78%) were on vasopressor therapy at the time of PET study. While global CBF was not significantly lower in patients with DCI (mean 39.4 ± 11.2 vs 43.0 ± 8.3 ml/100 g/min, p = 0.16), the burden of hypoperfusion was greater (20%, IQR 12%-23%, vs 12%, 9%-16%, p = 0.006). Burden of hypoperfusion performed better than global CBF as a predictor of DCI (area under the curve 0.71 vs 0.65, p = 0.044). Neither global CBF nor hypoperfusion burden differed in patients who responded to therapy compared to those who had not improved by the time of PET. Although hemispheric CBF was not lower in the symptomatic versus contralateral hemisphere in the 13 patients with focal deficits, there was a trend toward greater burden of hypoperfusion in the symptomatic hemisphere (21% vs 18%, p = 0.049). CONCLUSIONS: The burden of hypoperfusion was greater in patients with DCI, despite hemodynamic therapies, higher MAP, and equivalent global CBF. Similarly, hypoperfusion burden was greater in the symptomatic hemisphere of DCI patients with focal deficits even though the average CBF was similar to that in the contralateral hemisphere. Evaluating the proportion of the brain with critical hypoperfusion after SAH may better capture the extent of DCI than averaging CBF across heterogenous brain regions.

Clinical Trial Protocol: Phase 3, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group, Efficacy, and Safety Study Comparing EG-1962 to Standard of Care Oral Nimodipine in Adults with Aneurysmal Subarachnoid Hemorrhage [NEWTON-2 (Nimodipine Microparticles to Enhance Recovery While Reducing TOxicity After SubarachNoid Hemorrhage)].

BACKGROUND: Nimodipine is the only drug approved in the treatment of aneurysmal subarachnoid hemorrhage (aSAH) in many countries. EG-1962, a product developed using the Precisa™ platform, is an extended-release microparticle formulation of nimodipine that can be administered intraventricularly or intracisternally. It was developed to test the hypothesis that delivering higher concentrations of extended-release nimodipine directly to the cerebrospinal fluid would provide superior efficacy compared to systemic administration. RESULTS: A Phase 1/2a multicenter, controlled, randomized, open-label, dose-escalation study determined the maximum tolerated dose and supported the safety and tolerability of EG-1962 in patients with aSAH. EG-1962, 600 mg, was selected for a pivotal, Phase 3 multicenter, randomized, double-blind, placebo-controlled, parallel-group efficacy, and safety study comparing it to standard of care oral nimodipine in adults with aSAH. Key inclusion criteria are patients with a ruptured saccular aneurysm repaired by clipping or coiling, World Federation of Neurological Surgeons grade 2-4, and modified Fisher score of > 1. Patients must have an external ventricular drain as part of standard of care. Patients are randomized to receive intraventricular investigational product (EG-1962 or NaCl solution) and an oral placebo or oral nimodipine in the approved dose regimen (active control) within 48 h of aSAH. The primary objective is to determine the efficacy of EG-1962 compared to oral nimodipine. CONCLUSIONS: The primary endpoint is the proportion of subjects with favorable outcome (6-8) on the Extended Glasgow Outcome Scale assessed 90 days after aSAH. The secondary endpoint is the proportion of subjects with favorable outcome on the Montreal Cognitive Assessment 90 days after aSAH. Data on safety, rescue therapy, delayed cerebral infarction, and health economics will be collected. Trail registration NCT02790632.

Absolute risk and predictors of the growth of acute spontaneous intracerebral haemorrhage: a systematic review and meta-analysis of individual patient data.

BACKGROUND: Intracerebral haemorrhage growth is associated with poor clinical outcome and is a therapeutic target for improving outcome. We aimed to determine the absolute risk and predictors of intracerebral haemorrhage growth, develop and validate prediction models, and evaluate the added value of CT angiography. METHODS: In a systematic review of OVID MEDLINE-with additional hand-searching of relevant studies' bibliographies- from Jan 1, 1970, to Dec 31, 2015, we identified observational cohorts and randomised trials with repeat scanning protocols that included at least ten patients with acute intracerebral haemorrhage. We sought individual patient-level data from corresponding authors for patients aged 18 years or older with data available from brain imaging initially done 0·5-24 h and repeated fewer than 6 days after symptom onset, who had baseline intracerebral haemorrhage volume of less than 150 mL, and did not undergo acute treatment that might reduce intracerebral haemorrhage volume. We estimated the absolute risk and predictors of the primary outcome of intracerebral haemorrhage growth (defined as >6 mL increase in intracerebral haemorrhage volume on repeat imaging) using multivariable logistic regression models in development and validation cohorts in four subgroups of patients, using a hierarchical approach: patients not taking anticoagulant therapy at intracerebral haemorrhage onset (who constituted the largest subgroup), patients taking anticoagulant therapy at intracerebral haemorrhage onset, patients from cohorts that included at least some patients taking anticoagulant therapy at intracerebral haemorrhage onset, and patients for whom both information about anticoagulant therapy at intracerebral haemorrhage onset and spot sign on acute CT angiography were known. FINDINGS: Of 4191 studies identified, 77 were eligible for inclusion. Overall, 36 (47%) cohorts provided data on 5435 eligible patients. 5076 of these patients were not taking anticoagulant therapy at symptom onset (median age 67 years, IQR 56-76), of whom 1009 (20%) had intracerebral haemorrhage growth. Multivariable models of patients with data on antiplatelet therapy use, data on anticoagulant therapy use, and assessment of CT angiography spot sign at symptom onset showed that time from symptom onset to baseline imaging (odds ratio 0·50, 95% CI 0·36-0·70; p<0·0001), intracerebral haemorrhage volume on baseline imaging (7·18, 4·46-11·60; p<0·0001), antiplatelet use (1·68, 1·06-2·66; p=0·026), and anticoagulant use (3·48, 1·96-6·16; p<0·0001) were independent predictors of intracerebral haemorrhage growth (C-index 0·78, 95% CI 0·75-0·82). Addition of CT angiography spot sign (odds ratio 4·46, 95% CI 2·95-6·75; p<0·0001) to the model increased the C-index by 0·05 (95% CI 0·03-0·07). INTERPRETATION: In this large patient-level meta-analysis, models using four or five predictors had acceptable to good discrimination. These models could inform the location and frequency of observations on patients in clinical practice, explain treatment effects in prior randomised trials, and guide the design of future trials. FUNDING: UK Medical Research Council and British Heart Foundation.