Search

Angiographic vasospasm after aneurysmal subarachnoid hemorrhage (aSAH) is associated with delayed cerebral ischemia (DCI)-related cerebral infarction (radiological DCI) and worsened neurological outcome. Transcranial Doppler (TCD) measurements of cerebral blood flow velocity are commonly used after aSAH to screen for vasospasm; however, their association with cerebral infarction is not well characterized. We sought to determine whether time-varying TCD-measured vasospasm severity is associated with cerebral infarction and investigate the performance characteristics of different time/severity cutoffs for predicting cerebral infarction. We conducted a retrospective single-center cohort study of consecutive adult patients with aSAH with at least one TCD study between 2011 and 2020. The primary outcome was radiological DCI, defined as a cerebral infarction developing at least 2 days after any surgical or endovascular intervention without an alternative cause. Cox proportional hazards models were used to examine associations between time-varying vasospasm severity and radiological DCI. Optimal TCD-based time/severity thresholds for predicting radiological DCI were then determined. Of 262 patients with aSAH who underwent TCD studies, 27 (10%) developed radiological DCI. Patients with radiological DCI had higher modified Fisher scale scores and trended toward earlier onset of vasospasm. Adjusted for age, Hunt and Hess scores, and modified Fisher scale scores, the worst-vessel vasospasm severity was associated with radiological DCI (adjusted hazard ratio 1.7 [95% confidence interval 1.1–2.4]). Vasospasm severity within a specific vessel was associated with risk of delayed infarction in the territory supplied by that vessel. Optimal discrimination of patients with radiological DCI was achieved with thresholds of mild vasospasm on days 4–5 or moderate vasospasm on days 6–9, with negative predictive values greater than 90% and positive predictive values near 20%. TCD-measured vasospasm severity is associated with radiological DCI after aSAH. An early, mild TCD-based vasospasm severity threshold had a high negative predictive value, supporting its role as a screening tool to identify at-risk patients.

Animal experiments recently demonstrated that replacing urinary loses with crystalloid diminishes the therapeutic effect of mannitol by reducing the increase in osmolality. We aimed to investigate whether this effect is similarly seen in in brain-injured patients by studying the association between total body fluid balance (TBB) and the osmolar response to mannitol.We performed a retrospective cohort study of adult patients with acute brain injury between 2015 and 2021 who received ≥ 2 doses of mannitol within 8 hours and no intercurrent concentrated saline solution. We analyzed the association between the change in TBB (∆Of 6,145 patients who received mannitol, 155 patients met inclusion criteria (mean age 60 ± 17 years, 48% male, 83% white). The mean total mannitol dose was 2 ± 0.5 g/kg and the mean change in plasma osmolality was 7.9 ± 7.1 mOsm/kg. Each 1 L increase in ∆In patients with acute brain injury, a positive TBB is associated with a diminished mannitol-induced increase in plasma osmolality. Future prospective studies are needed to confirm these findings and their influence on the therapeutic effect of mannitol.

Cerebral edema is associated with worse outcome after acute stroke; however, the minimum clinically relevant threshold remains unknown. This study aimed to identify the minimal degree of midline shift (MLS) that predicts outcome in a cohort encompassing a broad range of patients with acute stroke. Patient-level data from six acute stroke clinical trials were combined with endovascular thrombectomy registries from two academic referral centers, generating a combined cohort of 1977 patients. MLS was extracted from the original trial data or measured on computed tomography or magnetic resonance imaging that was obtained a median of 47.0 h (interquartile range 27.0–75.1 h) after stroke onset. Logistic regression was performed to identify predictors of poor outcome and the minimal clinically relevant MLS threshold. The presence of MLS was a predictor of poor outcome, independent of baseline clinical and demographic factors (adjusted odds ratio 4.46, 95% confidence interval 3.56–5.59, p

IntroductionDisorders of consciousness, EEG background suppression and epileptic seizures are associated with poor outcome after cardiac arrest. The underlying patterns of anoxic brain injury associated with each remain unknown. Our objective was to identify the distribution of anoxic brain injury after cardiac arrest, as measured with diffusion MRI, and to define the regional correlates of disorders of consciousness, EEG background suppression, and seizures.MethodsWe analyzed patients from a prospectively-maintained, single-center database of unresponsive patients who underwent diffusion-weighted MRI following cardiac arrest (n = 204). We classified each patient based on recovery of consciousness (command-following) before discharge, the most continuous EEG background (burst suppression versus continuous), and the presence or absence of seizures. Anoxic brain injury was measured using the apparent diffusion coefficient (ADC) signal. We identified abnormalities in ADC relative to control subjects without cardiac arrest (n = 48) and used voxel lesion symptom mapping to identify regional associations with disorders of consciousness, EEG background suppression, and seizures. We then used a bootstrapped lasso regression procedure to identify robust, multivariate regional associations with each clinical and EEG variable. Finally, using area under receiver operating characteristic curves, we then compared the classification ability of the strongest regional associations to that of brain-wide summary measures.ResultsCompared to control subjects, cardiac arrest patients demonstrated a reduction in the ADC signal that was most significant in the occipital lobes. Disorders of consciousness were associated with reduced ADC most prominently in the occipital lobes, but also in the basal ganglia, medial thalamus and cerebellar nuclei. Regional injury more accurately classified patients with disorders of consciousness than whole-brain injury. Background suppression mapped to a similar set of brain regions, but regional injury could no better classify patients than whole-brain measures. Seizures were less common in patients with more severe anoxic injury, particularly in those with injury to the lateral temporal white matter.DiscussionAnoxic brain injury was most prevalent in posterior cerebral regions, and this regional pattern of injury was a better predictor of disorders of consciousness than whole-brain injury measures. EEG background suppression lacked a specific regional association, but patients with injury to the temporal lobe were less likely to have seizures. Collectively, our results suggest that the regional pattern of anoxic brain injury is relevant to the clinical and electrographic sequelae of cardiac arrest and may hold importance for prognosis.

BackgroundThe presence of angiographic vasospasm after aneurysmal subarachnoid hemorrhage (aSAH) is associated with delayed-cerebral ischemia (DCI)-related cerebral infarction and worsened neurological outcome. Transcranial doppler (TCD) measurements of cerebral blood velocity are commonly used after aSAH to screen for vasospasm. We sought to determine whether time-varying TCD measured vasospasm severity is associated with cerebral infarction and to investigate the performance characteristics of different time/severity cutoffs for predicting cerebral infarction.MethodsWe used a retrospective, single-center cohort of consecutive adult aSAH patients with angiographic vasospasm and at least one TCD study. Our primary outcome was DCI-related cerebral infarction, defined as an infarction developing at least 2 days after any surgical intervention without an alternative cause. Time-varying TCD vasospasm severity was defined ordinally (absent, mild, moderate, severe) by the most abnormal vessel on each post-admission hospital day. Cox proportional-hazards models were used to examine associations between time-varying vasospasm severity and infarction. The optimal TCD-based time/severity thresholds for predicting infarction were then identified using the Youden J statistic.ResultsOf 218 aSAH patients with angiographic vasospasm, 27 (12%) developed DCI-related infarction. As compared to those without infarction, patients with infarction had higher modified Fisher scale (mFS) scores, and an earlier onset of more-severe vasospasm. Adjusted for mFS, vasospasm severity was associated with infarction (aHR 1.9, 95% CI: 1.3-2.6). A threshold of at least mild vasospasm severity on hospital day 4 had a negative predictive value of 92% for the development of infarction, but a positive predictive value of 25%.ConclusionsIn aSAH, TCD-measured vasospasm severity is associated with DCI-related infarction. In a single-center dataset, a TCD-based threshold for predicting infarction had a high negative predictive value, supporting its role as an early screening tool to identify at-risk patients.