Effects of experimental intracerebral hemorrhage on blood flow, capillary permeability, and histochemistry

Brain edema formation and therapy after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) accounts for about 10% of all strokes in the United States of America causing a high degree of disability and mortality. There is initial (primary) brain injury due to the mechanical disruption caused by the hematoma. There is then secondary injury, triggered by the initial injury but also the release of various clot-derived factors (e.g., thrombin and hemoglobin). ICH alters brain fluid homeostasis. Apart from the initial hematoma mass, ICH causes blood-brain barrier disruption and parenchymal cell swelling, which result in brain edema and intracranial hypertension affecting patient prognosis. Reducing brain edema is a critical part of post-ICH care. However, there are limited effective treatment methods for reducing perihematomal cerebral edema and intracranial pressure in ICH. This review discusses the mechanisms underlying perihematomal brain edema formation, the effects of sex and age, as well as how edema is resolved. It examines progress in pharmacotherapy, particularly focusing on drugs which have been or are currently being investigated in clinical trials.

Cerebral Hemorrhage: Pathophysiology, Treatment, and Future Directions

Intracerebral hemorrhage (ICH) is a devastating form of stroke with high morbidity and mortality. This review article focuses on the epidemiology, cause, mechanisms of injury, current treatment strategies, and future research directions of ICH. Incidence of hemorrhagic stroke has increased worldwide over the past 40 years, with shifts in the cause over time as hypertension management has improved and anticoagulant use has increased. Preclinical and clinical trials have elucidated the underlying ICH cause and mechanisms of injury from ICH including the complex interaction between edema, inflammation, iron-induced injury, and oxidative stress. Several trials have investigated optimal medical and surgical management of ICH without clear improvement in survival and functional outcomes. Ongoing research into novel approaches for ICH management provide hope for reducing the devastating effect of this disease in the future. Areas of promise in ICH therapy include prognostic biomarkers and primary prevention based on disease pathobiology, ultra-early hemostatic therapy, minimally invasive surgery, and perihematomal protection against inflammatory brain injury.

Transcranial Doppler study in acute spontaneous intracerebral hemorrhage: The role of pulsatility index

Objective

Pulsatility index (PI) is a parameter calculated by transcranial Doppler sonography (TCD), which is commonly used for patients with subarachnoid hemorrhage or ischemic stroke. However, we performed a retrospective analysis of patients with acute spontaneous intracerebral hemorrhage (ICH) to assess the function of TCD, particularly the PI.

Methods

This study involved a total of 46 patients with acute ICH who received treatment at a single center between May 2013 and December 2014. Medical records of baseline characteristics, except for the modified Rankin scale, were obtained at initial evaluation in the emergency room, and TCD was used to calculate middle cerebral artery flow velocity (MFV) and PI at admission (baseline), 24 h, and 7 days. The PI and MFV values on the affected middle cerebral artery were compared with those on the contralateral side. Linear regression analysis was used for statistical analyses (SPSS 21.0, IBM Corp., Armonk, NY, USA).

Results

Statistical analysis indicated that sex, age, Glasgow coma scale, intraventricular hemorrhage, and hematoma size were not correlated with PI (p＞0.05); however, only PI was positively correlated with functional outcome at 6 months after treatment (R=0.846, p=0.002).

Conclusions

These results provide evidence that the parameter of PI is an independent determinant prognostic factor in acute spontaneous ICH. Further research is needed to investigate the influence of cerebral blood flow dynamics on a larger, more controlled, and more randomized basis.

Serum Hypoxia-Inducible Factor 1alpha Levels Correlate with Outcomes After Intracerebral Hemorrhage

Background

Serum hypoxia-inducible factor 1alpha (HIF-1α) is a key regulator in hypoxic and ischemic brain injury. We determined the relationship between serum HIF-1α levels and long-term prognosis plus severity of intracerebral hemorrhage (ICH).

Methods

A total of 97 ICH cases and 97 healthy controls were enrolled. Glasgow Coma Scale (GCS) score and hematoma volume were used to assess hemorrhagic severity. Glasgow Outcome Scale (GOS) score of 1–3 at post-stroke 90 days was defined as a poor outcome.

Results

Serum HIF-1α levels of ICH patients were significantly higher than those of healthy controls (median, 218.8 vs 105.4 pg/mL; P<0.001) and were substantially correlated with GCS score (r=−0.485, P<0.001), hematoma volume (r=0.357, P<0.001) and GOS score (r=−0.436, P<0.001). Serum HIF-1α levels >239.4 pg/mL discriminated patients at risk of 90-day poor outcome with sensitivity of 65.9% and specificity of 79.3% (area under the receiver operating characteristic curve, 0.725; 95% confidence interval, 0.625–0.811; P<0.001). Moreover, serum HIF-1α levels >239.4 pg/mL were independently associated with a poor 90-day outcome (odds ratio, 5.133; 95% confidence interval, 1.117–23.593; P=0.036).

Conclusion

Serum HIF-1α, in close correlation with hemorrhagic severity and poor 90-day outcome, may serve as a potential prognostic biomarker for ICH.

Secondary Hematoma Expansion and Perihemorrhagic Edema after Intracerebral Hemorrhage: From Bench Work to Practical Aspects

Intracerebral hemorrhages (ICH) represent about 10-15% of all strokes per year in the United States alone. Key variables influencing the long-term outcome after ICH are hematoma size and growth. Although death may occur at the time of the hemorrhage, delayed neurologic deterioration frequently occurs with hematoma growth and neuronal injury of the surrounding tissue. Perihematoma edema has also been implicated as a contributing factor for delayed neurologic deterioration after ICH. Cerebral edema results from both blood-brain barrier disruption and local generation of osmotically active substances. Inflammatory cellular mediators, activation of the complement, by-products of coagulation and hemolysis such as thrombin and fibrin, and hemoglobin enter the brain and induce a local and systemic inflammatory reaction. These complex cascades lead to apoptosis or neuronal injury. By identifying the major modulators of cerebral edema after ICH, a therapeutic target to counter degenerative events may be forthcoming.

Steps to consider in the approach and management of critically ill patient with spontaneous intracerebral hemorrhage

Spontaneous intracerebral hemorrhage is a type of stroke associated with poor outcomes. Mortality is elevated, especially in the acute phase. From a pathophysiological point of view the bleeding must traverse different stages dominated by the possibility of re-bleeding, edema, intracranial hypertension, inflammation and neurotoxicity due to blood degradation products, mainly hemoglobin and thrombin. Neurological deterioration and death are common in early hours, so it is a true neurological-neurosurgical emergency. Time is brain so that action should be taken fast and accurately. The most significant prognostic factors are level of consciousness, location, volume and ventricular extension of the bleeding. Nihilism and early withdrawal of active therapy undoubtedly influence the final result. Although there are no proven therapeutic measures, treatment should be individualized and guided preferably by pathophysiology. The multidisciplinary teamwork is essential. Results of recently completed studies have birth to promising new strategies. For correct management it’s important to establish an orderly and systematic strategy based on clinical stabilization, evaluation and establishment of prognosis, avoiding secondary insults and adoption of specific individualized therapies, including hemostatic therapy and intensive control of elevated blood pressure. Uncertainty continues regarding the role of surgery.

Progress in translational research on intracerebral hemorrhage: is there an end in sight?

Intracerebral hemorrhage (ICH) is a common and often fatal stroke subtype for which specific therapies and treatments remain elusive. To address this, many recent experimental and translational studies of ICH have been conducted, and these have led to several ongoing clinical trials. This review focuses on the progress of translational studies of ICH including those of the underlying causes and natural history of ICH, animal models of the condition, and effects of ICH on the immune and cardiac systems, among others. Current and potential clinical trials also are discussed for both ICH alone and with intraventricular extension.

Hemodynamic effects of mannitol infusion in patients with acute intracerebral hemorrhage

PURPOSE

To evaluate hemodynamic effects of mannitol infusion in patients with acute intracerebral hemorrhage.

METHODS

Thirty patients with acute intracerebral hemorrhage were enrolled. Transcranial doppler was used to detect variables of bilateral middle cerebral arteria (MCA) including mean velocity (Vm) and pulsitility index (PI) before and after 125 ml and 250 ml mannitol infusion (0, 30, 60, 90, 120, 180, 240 min).

RESULTS

When 125 ml or 250 ml mannitol was infused in patients with acute intracerebral hemorrhage, Vm of bilateral MCA elevated, and reached the top at 30 min, and then decreased. PI decreased in the affected MCA (250 ml) and in the unaffected MCA (125 ml and 250 ml).

CONCLUSION

Mannitol infusion in patients with acute intracerebral hemorrhage can improve cerebral blood flow in bilateral hemispheres and decrease intracranial pressure in the hemorrhagic hemisphere (250 ml) and in the nonhemorrhagic hemisphere (125 ml and 250 ml).

Brain microbleeds: distribution and influence on hematoma and perihematomal edema in patients with primary intracerebral hemorrhage

Brain microbleed is a marker of small vessel microhemorrhagic or microaneurysmal lesions, which may induce intracerebral hemorrhage (ICH). This study to prospectively evaluated the association between microbleeds, hematoma and perihematomal edema volume, and various clinical data, as well as patient outcome. Thirty-one patients with ICH and 31 healthy age-matched subjects were enrolled in our study. They were divided into two groups according to the presence or absence of microbleeds detected by MRI. Serial clinical and laboratory data were recorded. Modified Rankin Scale and Barthel Index were estimated three months after hemorrhage. The major location of microbleeds among patients with ICH was the basal ganglia. The volume of perihematomal edema was correlated with the initial hematoma volume on the first, fifth and seventh days after hemorrhage in patients with microbleeds. For patients without microbleeds, this correlation was also significant on the seventh day. Cerebral microbleeds in patients with ICH, especially in the basal ganglia region, represent micro-angiopathy, and are associated with leakage of blood and formation of perihemorrhage edema. Brain microbleeds found in patients with ICH warrant further investigation for evaluation of stroke risk.

Thrombin and hemin as central factors in the mechanisms of intracerebral hemorrhage-induced secondary brain injury and as potential targets for intervention

Intracerebral hemorrhage (ICH) is a subtype of stoke that may cause significant morbidity and mortality. Brain injury due to ICH initially occurs within the first few hours as a result of mass effect due to hematoma formation. However, there is increasing interest in the mechanisms of secondary brain injury as many patients continue to deteriorate clinically despite no signs of rehemorrhage or hematoma expansion. This continued insult after primary hemorrhage is believed to be mediated by the cytotoxic, excitotoxic, oxidative, and inflammatory effects of intraparenchymal blood. The main factors responsible for this injury are thrombin and erythrocyte contents such as hemoglobin. Therapies including thrombin inhibitors, N-methyl-D-aspartate antagonists, chelators to bind free iron, and antiinflammatory drugs are currently under investigation for reducing this secondary brain injury. This review will discuss the molecular mechanisms of brain injury as a result of intraparenchymal blood, potential targets for therapeutic intervention, and treatment strategies currently in development.

Evaluation of transcranial Doppler flow velocity changes in intracerebral hemorrhage rats using ultrasonography

This study investigated the blood flow velocity changes in seven major arteries in rat brain before and after intracerebral hemorrhage (ICH) using high frequency transcranial Doppler (TCD) ultrasonography (13-4 MHz). Eighteen adult Sprague Dawley rats received either the collagenase-injection surgery (ICH, n=12) or the saline-injection surgery (control, n=6) after baseline TCD flow velocity values were recorded. The TCD flow velocity changes were measured at 0.5h after the surgery and daily for the following 8 days in seven major cerebral arteries, including bilateral internal carotid arteries, bilateral middle cerebral arteries (MCAs), bilateral posterior cerebral arteries (PCAs), and basilar artery. The results showed a significant decrease of TCD flow velocity in the right MCA at 0.5 h and 24 h after the collagenase-injection surgery, and in the right PCA at 0.5 h in the ICH group rats. The TCD flow velocities in these two arteries gradually increased and then returned to the baseline values in the following days. The control group rats did not show significant changes in TCD flow velocity in all monitored arteries. This study demonstrates the feasibility and reliability of monitoring TCD flow velocity in cerebral arteries using ultrasonography technique in a rat ICH model. The results of this study extend our knowledge in the cerebrovascular changes during intracranial hemorrhage and suggest a possibility of clinical application of TCD ultrasonography in studying the dynamic cerebral circulation after strokes. Moreover, this method could be extensively applied in further studies using potential neuroprotective treatments that affect the cerebral dynamics in the intracerebral hemorrhage.

Antihypertensive treatment of acute intracerebral hemorrhage by intravenous nicardipine hydrochloride: prospective multi-center study

The authors performed a multicenter prospective study to evaluate the feasibility and safety of intravenous nicardipine hydrochloride for acute hypertension in patients with intracerebral hemorrhage (ICH). This study included 88 patients (mean age: 58.3 yr, range 26-87 yr) with ICH and acute hypertension in 5 medical centers between August 2008 and November 2010, who were treated using intravenous nicardipine. Administration of nicardipine resulted in a decrease from mean systolic blood pressure (BP) (175.4 ± 33.7 mmHg) and diastolic BP (100.8 ± 22 mmHg) at admission to mean systolic BP (127.4 ± 16.7 mmHg) and diastolic BP (67.2 ± 12.9 mmHg) in 6 hr after infusion (P < 0.001, mixed-effect linear models). Among patients who underwent follow-up by computed tomography, hematoma expansion at 24 hr (more than 33% increase in hematoma size at 24 hr) was observed in 3 (3.4%) of 88 patients. Neurological deterioration (defined as a decrease in initial Glasgow coma scale ≥ 2) was observed in 2 (2.2%) of 88 patients during the treatment. Aggressive nicardipine treatment of acute hypertension in patients with ICH can be safe and effective with a low rate of neurological deterioration and hematoma expansion.

Clinical practice guidelines in intracerebral haemorrhage

Intracerebral haemorrhage accounts for 10%-15% of all strokes; however it has a poor prognosis with higher rates of morbidity and mortality. Neurological deterioration is often observed during the first hours after onset and determines poor prognosis. Intracerebral haemorrhage, therefore, is a neurological emergency which must be diagnosed and treated properly as soon as possible. In this guide we review the diagnostic procedures and factors that influence the prognosis of patients with intracerebral haemorrhage and we establish recommendations for the therapeutic strategy, systematic diagnosis, acute treatment and secondary prevention for this condition.

PET in Cerebrovascular Disease

Investigation of the interplay between the cerebral circulation and brain cellular function is fundamental to understanding both the pathophysiology and treatment of stroke. Currently, PET is the only technique that provides accurate, quantitative in vivo regional measurements of both cerebral circulation and cellular metabolism in human subjects. We review normal human cerebral blood flow and metabolism and human PET studies of ischemic stroke, carotid artery disease, vascular dementia, intracerebral hemorrhage and aneurysmal subarachnoid hemorrhage and discuss how these studies have added to our understanding of the pathophysiology of human cerebrovascular disease.

Simvastatin and atorvastatin improve neurological outcome after experimental intracerebral hemorrhage

BACKGROUND AND PURPOSE

This study investigates the effects of statin treatment on experimental intracerebral hemorrhage (ICH) using behavioral, histological, and MRI measures of recovery.

METHODS

Primary ICH was induced in rats. Simvastatin (2 mg/kg), atorvastatin (2 mg/kg), or phosphate-buffered saline (n=6 per group) was given daily for 1 week. MRI studies were performed 2 to 3 days before ICH, and at 1 to 2 hours and 1, 2, 7, 14, and 28 days after ICH. The ICH evolution was assessed via hematoma volume measurements using susceptibility-weighted imaging (SWI) and tissue loss using T2 maps and hematoxylin and eosin (H&E) histology. Neurobehavioral tests were done before ICH and at various time points post-ICH. Additional histological measures were performed with doublecortin neuronal nuclei and bromodeoxyuridine stainings.

RESULTS

Initial ICH volumes determined by SWI were similar across all groups. Simvastatin significantly reduced hematoma volume at 4 weeks (P=0.002 versus control with acute volumes as baseline), whereas that for atorvastatin was marginal (P=0.09). MRI estimates of tissue loss (% of contralateral hemisphere) for treated rats were significantly lower (P=0.0003 and 0.001, respectively) than for control at 4 weeks. Similar results were obtained for H&E histology (P=0.0003 and 0.02, respectively). Tissue loss estimates between MRI and histology were well correlated (R2=0.764, P<0.0001). Significant improvement in neurological function was seen 2 to 4 weeks post-ICH with increased neurogenesis observed.

CONCLUSIONS

Simvastatin and atorvastatin significantly improved neurological recovery, decreased tissue loss, and increased neurogenesis when administered for 1 week after ICH.

Spontaneous intracerebral haemorrhage in adults: a literature overview

BACKGROUND

A large number of reports have analysed epidemiology, pathogenesis, symptomatology, diagnostics and options for medical and surgical treatment of intracerebral haemorrhage. Nevertheless, management still remains controversial. The purpose of the present review is to summarise the clinical data and derive a current updated management concept as a result.

METHODS

The analysis was based on a Medline search to November 2006 for the term "intracerebral haemorrhage" (ICH). The clinical query functions were optimised for aetiology, diagnosis and therapy to limit the results. A total of 103 articles were found eligible for review.

FINDINGS

Race, age and sex influence the occurrence of ICH. Moreover, hypertension and alcohol consumption are the paramount risk factors. The most frequent pathophysiological mechanism of ICH seems to be a degenerative vessel wall change and, in consequence, rupture of small penetrating arteries and arterioles of 50-200 microm in diameter. The symptomatology depends on the size of ICH, possible rebleeding and the occurrence of hydrocephalus or seizures. The outcome is worse with concomitant occurrence of intraventricular haemorrhage. Treatment with recombinant factor VIIa (rFVIIa) within four hours after the onset of ICH limits the growth of haematoma, reduces mortality and improves functional outcome. Minimally invasive surgery tends to improve functional outcome.

CONCLUSION

A systematic knowledge of currently available data on epidemiology, pathogenesis and symptomatology, the use of diagnostics and the different conservative and surgical treatment options can lead to a balanced management strategy for patients with ICH.

Hyperbaric oxygen for experimental intracerebral hemorrhage

Acute brain edema formation contributes to brain injury after intracerebral hemorrhage (ICH). It has been reported that hyperbaric oxygen (HBO) is neuroprotective in cerebral ischemia, subarachnoid hemorrhage, and brain trauma. In this study, we investigated the effects of HBO on brain edema following ICH in rats. Male Sprague-Dawley rats received intracerebral infusion of autologous whole blood, thrombin, or ferrous iron. HBO (100% O2, 3.0 ATA for 1 h) was initiated 1 h after intracerebral injection. Control rats were exposed to air at room pressure. Brains were sampled at 24 or 72 h for water content, ion measurement, and Western blot analysis. We found that 1 session of HBO reduced perihematomal brain edema (p < 0.05) 24 h after ICH. HBO also reduced heat shock protein-32 (HSP-32) levels (p < 0.05) in ipsilateral basal ganglia 24h after ICH. However, HBO failed to attenuate thrombin-induced brain edema and exaggerated ferrous iron-induced brain edema (p < 0.05). Three sessions of HBO also failed to reduce brain edema 72h after ICH. In summary, HBO reduced early perihematomal brain edema and HSP-32 levels in brain. HBO-related brain protection does not occur through reduction in thrombin toxicity because HBO failed to attenuate thrombin-induced brain edema. Our results also indicate that HBO treatment after hematoma lysis for ICH may be harmful, since HBO amplifies iron-induced brain edema.

Antihypertensive Treatment of Acute Cerebral Hemorrhage (ATACH): rationale and design

This trial is a multicenter open-labeled pilot trial to determine the tolerability and safety of three escalating levels of antihypertensive treatment goals for acute hypertension in 60 subjects with supratentorial intracerebral hemorrhage (ICH). The pilot trial is the natural development of numerous case series evaluating the effect of antihypertensive treatment of acute hypertension in subjects with ICH. The proposed trial will have important public health implications by providing necessary information for a definitive phase III study regarding the efficacy of antihypertensive treatment of acute hypertension in subjects with ICH. The specific aims of the present pilot study are to: (1) Determine the tolerability of the treatment as assessed by achieving and maintaining three different systolic blood pressure goals with intravenous nicardipine infusion for 18 to 24 hours postictus in subjects with ICH who present within 6 hours of symptom onset; (2) Define the safety, assessed by the rate of neurological deterioration during treatment and serious adverse events, of three escalating systolic blood pressure treatment goals using intravenous nicardipine infusion; and (3) Obtain preliminary estimates of the treatment effect using the rate of hematoma expansion (within 24 hours) and modified Rankin scale and Barthel index at 3 months following symptom onset.

Reducing the risk of ICH enlargement

Intracerebral hemorrhage (ICH) comprises 15% of all strokes, and carries the highest risk of mortality and poor long-term outcome. ICH has long been recognized as the least treatable form of stroke, and hematoma volume as the strongest single predictor of mortality and outcome. CT-based studies have found that early substantial hematoma expansion occurs in 18-38% of patients initially scanned within 3 h of symptom onset. This finding is associated with early neurological deterioration and an increased risk of poor outcome. Ultra-early hemostatic therapy might be beneficial in preventing hematoma growth, resulting in improved mortality and neurological function. Recombinant activated factor VII (rFVIIa) promotes local hemostasis in the presence or absence of coagulopathy at sites of vascular injury, and is a promising treatment for arresting active bleeding in ICH. The safety and feasibility of this approach was confirmed in a phase IIb randomized, double-blind, placebo-controlled, dose-ranging trial of 399 patients with non-coagulopathic ICH. Administration of rFVIIa within 4 h of ICH onset resulted in a significant reduction of hematoma expansion at 24 h, and reduced mortality and improved functional outcome at 90 days. A confirmatory phase III trial (The FAST Trial) to confirm these results will complete enrollment in the end of 2006.

Acute hypertension in intracerebral hemorrhage: pathophysiology and treatment

Non-traumatic or spontaneous intracerebral hemorrhage (ICH) is defined as intra-parenchymal bleeding with or without extension into the ventricles and rarely into the subarachoid space. Primary ICH in most cases is associated with chronic hypertension. Acute hypertension is associated with hematoma expansion, and poor neurological outcome. The treatment of hypertension in acute ICH is a topic of controversy. Experiments have shown an area of ischemia around the hematoma, with the reduction of regional cerebral blood flow (CBF) secondary to compression of microvasculature. Not all scientific results agree with the above findings. Recent studies have shown that CBF decreases in the perihematoma region but with concomitant reduction of cerebral metabolism, which would argue against an area of ischemia in the perihematoma region. Based on the above result, there have been several clinical trials looking at clinical outcome and decrease in hematoma expansion rates with reduction of blood pressure acutely after ICH. The parameters for the blood pressure control are still under investigation. The American Heart Association has put forward guidelines for blood pressure control which have been adopted in the centers around the country. We have described the protocol we use at our center for the blood pressure control in patients with acute ICH.

Surgical treatment of intracerebral haemorrhage

PURPOSE OF REVIEW

Controversy still exists about the management of spontaneous intracerebral haemorrhage. This review summarizes our current knowledge on indications and benefits of surgery for intracerebral haemorrhage. It further describes the detailed meta-analysis of the surgical results in lobar (superficial) supratentorial intracerebral haemorrhage, summarizes the limited information on the surgical treatment of cerebellar intracerebral haemorrhage, and identifies three ongoing trials.

RECENT FINDINGS

A meta-analysis of 12 prospective randomized controlled trials of neurosurgical intervention in spontaneous intracerebral haemorrhage shows a strong trend to reduced mortality (0.85; 95% confidence interval 0.71-1.02). There is an apparent significant benefit from surgery in the three trials in which lobar intracerebral haemorrhage was identified in relation to both death and disability (0.58; 95% confidence interval 0.36 - 0.92). No surgical trial data are available for spontaneous cerebellar intracerebral haemorrhage or for any type of traumatic intracranial haemorrhage. Three trials are ongoing to resolve existing uncertainties.

SUMMARY

Clinicians are encouraged to discover if the suspected beneficial role of surgery truly exists by randomizing patients with intracerebral haemorrhage in the ongoing prospective randomized controlled trials in the following circumstances: lobar intracerebral haemorrhage (clot reaches to within 1 cm of the cortical surface), STICH II; intraventricular haemorrhage (clot maximum size of 30 ml), CLEAR IVH; deep intracerebral haemorrhage and minimal invasive surgery, MISTIE.

Mast cell blocking reduces brain edema and hematoma volume and improves outcome after experimental intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is associated with high mortality and disability, and there is no widely approved clinical therapy. Poor outcome after ICH results mostly from a mass effect owing to enlargement of the hematoma and brain swelling, leading to displacement and disruption of brain structures. Cerebral mast cells (MC) are resident inflammatory cells that are located perivascularly and contain potent vasoactive, proteolytic, and fibrinolytic substances. We previously found pharmacological MC stabilization and genetic MC deficiency to be associated with up to 50% reduction of postischemic brain swelling in rats. Here, we studied the role of MC and MC stabilization in ICH using in vivo magnetic resonance imaging and ex vivo digital imaging for calculating brain edema and hematoma volume. In a rat ICH model of autologous blood injection into the basal ganglia, four groups of Wistar rats received either saline or sodium cromoglycate (MC stabilizer, two groups) or compound 48/80 (MC degranulator). Evaluated 24 h later, MC stabilization had resulted in highly significantly better neurologic scores (P<0.001), decrease mortality (P=0.002), less brain swelling (P<0.001), and smaller hematoma volume growth (P<0.001) compared with saline and compound 48/80. Moreover, to support our hypothesis, we induced ICH in MC-deficient rats and their wild-type littermates (WT). MC-deficient rats responded with significantly better neurologic scores (P<0.001), decrease mortality (0% versus 25%), less brain swelling (P<0.05), and smaller hematoma growth (P<0.05) than WT. The role of MC deserves a close evaluation as a potential target in the development of novel forms of ICH therapy.

Diffusion-weighted magnetic resonance imaging versus computed tomography in the diagnosis of acute ischemic stroke

Current treatment protocols using reperfusion therapy for acute ischemic stroke rely on non-contrast computed tomography (NCCT), with most indications including the absence of acute hemorrhage or large volume of infarction in the presence of clinical signs and symptoms. This predictably results in a significant incidence of the administration of reperfusion therapy to patients with "stroke mimics," such as migraine headache or Todd's paralysis after a seizure. Diffusion-weighted imaging (DWI) is a technique based on magnetic resonance imaging (MRI) that may be more sensitive and specific for acute cerebral ischemia than NCCT. In addition, data for techniques such as perfusion-weighted imaging can be acquired with minimal additional time required. This may allow better risk assessment of a clinical response to reperfusion therapy vs. the possibility of hemorrhagic complications. This article describes a methodical review of studies comparing the sensitivity, specificity, positive predictive value, and negative predictive value of DWI vs. NCCT in the evaluation of acute ischemic stroke. Data from studies meeting our screening criteria are combined to produce overall values for each.

Treatment of acute hypertension in patients with intracerebral hemorrhage using American Heart Association guidelines

OBJECTIVE

To determine the feasibility and safety of treatment of acute hypertension in patients with intracerebral hemorrhage within 24 hrs of symptom onset. Elevated blood pressure, observed in up to 56% of patients with intracerebral hemorrhage, may predispose to hematoma expansion; on the other hand, reduction of blood pressure may reduce hematoma expansion and subsequent death and disability.

DESIGN

Single-center prospective registry supplemented by retrospective chart review.

SETTINGS

University-affiliated medical center with dedicated stroke service.

PATIENTS

All patients admitted to the stroke service with spontaneous intracerebral hemorrhage and acute hypertension within 24 hrs of symptom onset.

INTERVENTION

Patients were treated with intravenous nicardipine within 24 hrs of symptom onset to reduce and maintain mean arterial pressure of <130 mm Hg. The mean arterial pressure goal was consistent with the American Heart Association guidelines.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the tolerability of the treatment as assessed by achieving and maintaining the mean arterial pressure goals for 24 hrs after initiation of intravenous nicardipine infusion. Other end points ascertained were: neurologic deterioration defined by a decline in Glasgow Coma Scale from pretreatment assessment by >or=2 points or increase in National Institutes of Health Stroke Scale score by >or=2 points and hemorrhage growth defined as an increase in the volume of intraparenchymal hemorrhage of >33% as measured by image analysis on the 24-hr computed tomographic scan compared with the baseline computed tomographic scan. Rates of favorable outcome and death were ascertained at 1 month. Of the total 46 patients admitted with intracerebral hemorrhage in our service, 29 patients were treated. Mean age of the treated patients was 58 +/- 13 yrs; ten were women. Initial National Institutes of Health Stroke Scale ranged from 1 to 38. The primary outcome of tolerability was achieved in 25 of the 29 patients (86%). Neurologic deterioration was observed in 4 of 29 patients. Hematoma enlargement was observed in five patients. Favorable outcome (defined as modified Rankin scale of <or=2) and death at 1-month was observed in 11 (38%) and 9 (31%) of the 29 patients, respectively.

CONCLUSIONS

We observed a high rate of tolerability among patients with intracerebral hemorrhage who were treated with intravenous nicardipine using mean arterial pressure goals defined by American Heart Association guidelines within 24 hrs of symptom onset.

Quantitative analysis of influence of sevoflurane on the reactivity of microglial cells in the course of the experimental model of intracerebral haemorrhage

BACKGROUND

Microglial cells play an important role in the pathophysiology of intracerebral haemorrhage. We have examined the possible influence of sevoflurane on the reactivity of microglial cells during intracranial haemorrhage.

METHODS

Forty adult male rats were divided into two groups. All animals were anaesthetized with fentanyl, dehydrobenzperidol and midazolam. In the experimental group animals additionally received sevoflurane 2.2 vol% end-tidal concentration. Intracranial haemorrhage was produced through infusion of blood into the striatum. The microglial cell population (numerical density of immunoreactive cells and their distribution) was assessed on days 1, 3, 7, 14 and 21 after producing a haematoma using antibodies OX42 and OX6.

RESULTS

In the control group significant differences in the density of OX42-ir cells between 3rd and 7th (81.86 vs. 129.99) (95% CI: -77.99 to -18.25, P = 0.0035) and between 14th and 21st (105.36 vs. 63.81) (95% CI: 13.21 to 69.89, P = 0.006) survival days were observed. However, significant increase of percentage of amoeboid OX42-ir cells between 3rd and 7th (0.98 vs. 48.71) (95% CI: -52.17 to -43.30, P = 0.0001) and between 7th and 14th (48.71 vs. 58.47) (95% CI: -13.96 to -5.55, P = 0.0002) and then their decrease - between 14th and 21st (58.47 vs. 31.74) (95% CI: 22.52 to 30.93, P = 0.0001) days of observation were noted. In the sevoflurane groups OX42-ir cells were not found. On the 3rd day the density of OX6-ir cells in the sevoflurane group was significantly lower than that in the control group (12.39 vs. 34.57) (95% CI: -49.78 to -2.96, P = 0.02). The percentage of an amoeboid form of OX6-ir cells was significantly lower in the sevoflurane group than that in the control group (27.31 vs. 82.03) (95% CI: -72.52 to -36.92, P = 0.0001) (58.76 vs. 82.37) (95% CI: -38.81 to -8.41, P = 0.003) (42.87 vs. 81.55) (95% CI: -53.23 to -24.10, P = 0.0001) respectively for 3rd, 7th and 14th days of survival.

CONCLUSION

Administration of sevoflurane during anaesthesia in animals with intracerebral haemorrhage evoked a decrease of activation of the microglial cells.

Rapid administration of antifibrinolytics and strict blood pressure control for intracerebral hemorrhage

OBJECTIVE

Hematoma growth is a major cause of poor outcome in patients with intracerebral hemorrhage. We evaluated the efficacy of a combination of rapid antifibrinolytic therapy and strict blood pressure control for prevention of hematoma growth in this retrospective study.

METHODS

Systolic blood pressure was strictly controlled below 150 mm Hg by use of intravenously administered nicardipine (BPC). Prolonged infusion of antifibrinolytic therapy was given by intravenous administration of 1 g tranexamic acid over a period of 6 hours (PAF). Rapid administration of antifibrinolytic therapy was given by intravenous administration of 2 g tranexamic acid over a period of 10 minutes (RAF). Immediately after diagnosis of intracerebral hemorrhage on computed tomographic scan, 156 patients who were admitted within 24 hours of onset were treated with either a combination of PAF and BPC (PAF group) or a combination of RAF and BPC (RAF group). The incidence of hematoma growth determined by a second computed tomographic scan the day after admission was compared between the PAF and the RAF groups.

RESULTS

Hematoma growth was observed in 11 (17.5%) of 63 patients in the PAF group and 4 (4.3%) of 93 patients in the RAF group using a 20% cutoff value for hematoma enlargement. The RAF group showed a significantly low incidence of hematoma growth compared with the PAF group (P < 0.05). Between the two groups, there was no significant difference in any of the other factors reported to affect hematoma growth.

CONCLUSION

The combination of rapid administration of antifibrinolytics and strict blood pressure control may prevent hematoma growth in patients with intracerebral hemorrhage.

Mechanisms of brain injury after intracerebral haemorrhage

The past decade has resulted in a rapid increase in knowledge of mechanisms underlying brain injury induced by intracerebral haemorrhage (ICH). Animal studies have suggested roles for clot-derived factors and the initial physical trauma and mass effect as a result of haemorrhage. The coagulation cascade (especially thrombin), haemoglobin breakdown products, and inflammation all play a part in ICH-induced injury and could provide new therapeutic targets. Human imaging has shown that many ICH continue to expand after the initial ictus. Rebleeding soon after the initial haemorrhage is common and forms the basis of a current clinical trial using factor VIIa to prevent rebleeding. However, questions about mechanisms of injuries remain. There are conflicting data on the role of ischaemia in ICH and there is uncertainty over the role of clot removal in ICH therapy. The next decade should bring further information about the underlying mechanisms of ICH-induced brain injury and new therapeutic interventions for this severe form of stroke. This review addresses our current understanding of the mechanisms underlying ICH-induced brain injury.

Benefits of adapting minimal invasive techniques to selected patients with spontaneous supratentorial intracerebral hematomas

OBJECTIVES

This study assesses the benefits of adapting minimal invasive techniques (MIT) to selected patients with spontaneous supratentorial intracerebral hematomas (SSICHs).

METHODS

The study compares the post-operative residual clot volume and clinical outcome of 89 selected, MIT evacuated SSICH-patients to those of 138 unselected cases operated in our department. Selection criteria includes patient age, early admission and MIT treatment. MIT treatment included: 28 patients with deep SSICHs smaller than 30 cm3 associated with intraventricular bleeding who underwent neuronavigation-guided stereotactic catheter lysis, 37 patients with deep hematomas larger than 30 cm3 and 24 patients with a lobar hemorrhage compressing eloquent regions who underwent microsurgical (endoscopic or neuronavigation assisted) clot aspiration.

RESULTS

In eight (9%) of the patients in the MIT group, the CT scan control showed a residual clot smaller than 30% of the initial hemorrhage. The neurological condition 3 months later revealed 24 (26.9%) of these patients having a severe disability and 46 (51.6%) patients independent or slightly disabled. Nineteen patients (21.9%) died or remained vegetative. In the control group, 48 (34.7%) cases showed residual clots (<30%). Sixty-two (44.9%) patients of this group were severely disabled and only 40 (28.9%) were independent. Thirty-six (26%) patients died or were vegetative. There was a p<0.001 significant difference in volume of residual clots as well as p<0.01 for the outcome between the two groups.

CONCLUSIONS

Adapting minimally invasive techniques to case selection improves the effectiveness of clot removal and the outcome of the patients with SSICHs.

A prospective multicenter study to evaluate the feasibility and safety of aggressive antihypertensive treatment in patients with acute intracerebral hemorrhage

The authors performed a multicenter prospective observational study to evaluate the feasibility and safety of intravenous antihypertensive protocol for acute hypertension in patients with intracerebral hemorrhage (ICH). Twenty-seven patients with ICH and acute hypertension (mean age 61.37 +/- 14.27; 10 were men) were treated to maintain the systolic blood pressure (BP) below 160 mm Hg and diastolic BP below 90 mm Hg within 24 hours of symptom onset. Neurological deterioration (defined as a decrease in initial Glasgow Coma Scale score > or = 2) was observed in 2 (7.4%) of 27 patients during treatment. Among patients who underwent follow-up computed tomography, hematoma expansion (more than 33% increase in hematoma size at 24 hours) was observed in 2 (9.1%) of 22 patients. Patients treated within 6 hours of symptom onset were more likely to be functionally independent (modified Rankin scale < or = 2) at 1 month compared with patients who were treated between 6 and 24 hours (8 of 18 versus 0 of 9,P = .03). Aggressive pharmacological treatment of acute hypertension in patients with ICH can be initiated early with a low rate of neurological deterioration and hematoma expansion.

Changes in cerebral hemodynamics and cerebral oxygenation during surgical evacuation for hypertensive intracerebral putaminal hemorrhage

OBJECTIVES

The aim of this study was to evaluate the changes in cerebral hemodynamics, tissue oxygenation and blood flow before and after surgery for spontaneous intracerebral hematomas.

METHODS

Eleven patients who underwent surgical decompression of spontaneous putaminal hematoma were studied. Intracranial pressure (ICP), cerebral perfusion pressure (CPP), brain tissue oxygen (PtiO2), and carbon dioxide tensions (PtiCO2), brain pH and regional cerebral blood flow (rCBF) were recorded prior to removing the bone flap and then on skin closure on completion of the operation.

RESULTS

Following surgical decompression, mean ICP decreased significantly (P < 0.05); mean CPP, PtiO2, brain pH and rCBF improved although the changes were not significant.

CONCLUSION

Surgical decompression for spontaneous intracerebral hematomas leads to significant reductions in ICP. This is accompanied by improvements in CPP, PtiO2 and rCBF in the penumbra.

Reliability in detection of hemorrhage in acute stroke by a new three-dimensional gradient recalled echo susceptibility-weighted imaging technique compared to computed tomography: a retrospective study

PURPOSE

To compare the sensitivity of magnetic resonance (MR) susceptibility-weighted imaging (SWI) with conventional MR sequences and computed tomography (CT) in the detection of hemorrhage in an acute infarct.

MATERIALS AND METHODS

A series of 84 patients suspected of having acute strokes had both CT and MR imaging (MRI) scans with diffusion-weighted imaging (DWI) and SWI. The SWI sequence is a new high-resolution three-dimensional (3D) imaging technique that amplifies phase to enhance the magnitude contrast.

RESULTS

Thirty-eight of 84 cases showed abnormal DWI consistent with acute infarct. Of the 38, SWI showed evidence of hemorrhage in 16 cases, compared to eight cases with spin echo (SE) T2, seven cases with fluid attentuated inversion recovery (FLAIR), and only five cases with CT. In a subset of 17 cases of acute infarct who had both two-dimensional gradient recalled echo (2D-GRE) T2*-weighted imaging and SWI, in addition to conventional MRI, evidence of hemorrhage was seen in 10 cases using SWI, compared to seven cases with 2D-GRE T2*.

CONCLUSION

SWI proved to be a powerful new approach for visualizing hemorrhage in acute stroke compared to CT and conventional MRI methods.

Mmp-9 deficiency enhances collagenase-induced intracerebral hemorrhage and brain injury in mutant mice

Matrix metalloproteinase-9 (MMP-9) participates in the disregulation of blood-brain barrier during hemorrhagic transformation, and exacerbates brain injury after cerebral ischemia. However, the consequences of long-term inhibition or deficiency of MMP-9 activity (which might affect normal collagen or matrix homeostasis) remains to be determined. The authors investigated how MMP-9 gene deficiency enhances hemorrhage and increases mortality and neurologic deficits in a collagenase-induced intracerebral hemorrhage (ICH) model in MMP-9-knockout mice. MMP-9-knockout and corresponding wild-type mice at 20 to 35 weeks were used to model an aged population (because advanced age is a significant risk factor in human ICH). Collagenase VII-S (0.5 microL, 0.075 U) was injected into the right basal ganglia in mice and mortality, neurologic deficits, brain edema, and hemorrhage size measured. In addition, MMP-9 activity, brain collagen content, blood coagulation, cerebral arterial structure, and expressions of several MMPs were examined. Increased hemorrhage and brain edema that correlated with higher mortality and neurologic deficits were found in MMP-9-knockout mice. No apparent structural changes were observed in cerebral arteries, even though brain collagen content was reduced in MMP-9-knockout mice. MMP-9-knockout mice did exhibit an enhanced expression of MMP-2 and MMP-3 in response to ICH. The results indicate that a deficiency of MMP-9 gene in mutant mice increases collagenase-induced hemorrhage and the resulting brain injury. The intriguing relationship between MMP-9 deficiency and collagenase-induced ICH may reflect the reduction in collagen content and an enhanced expression of MMP-2 and MMP-3.

Glutamate receptor blockade attenuates glucose hypermetabolism in perihematomal brain after experimental intracerebral hemorrhage in rat

BACKGROUND AND PURPOSE

Intracerebral hemorrhage has no effective treatment. The delayed appearance of edema, apoptosis, and inflammation in perihematomal brain suggests that these events may be targets for therapeutic intervention. To develop successful treatments, we must learn more about the effects of hemorrhage on brain tissue. In this study, we investigated the acute metabolic effects of intrastriatal hemorrhage in rat brain.

METHODS

Lysed blood or saline (50 microL each) was injected into the striatum of male Sprague-Dawley rats. The rats recovered for 1 to 72 hours before injection of [14C]-2-deoxyglucose (intraperitoneally) 30 minutes before decapitation. Animals were pretreated with the N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor antagonists dizolcilpine maleate (MK-801; 1 mg/kg) or 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo[f]quinoxaline (NBQX; 30 mg/kg), or saline vehicle. Additional animals received intrastriatal injections of glutamate (1.0 mmol/L), NMDA (1.0 mmol/L), or AMPA (0.1 mmol/L) in the place of blood. Semiquantitative autoradiographs from the brains were analyzed to determine the effects of hemorrhage on relative glucose metabolism.

RESULTS

We found an acute phase of increased [14C]-2-deoxyglucose uptake in the perihematomal region that peaks 3 hours after lysed blood injection. Saline injections had no effect on striatal glucose utilization. The increased [14C]-2-deoxyglucose uptake produced by the hemorrhages was blocked by pretreatment with MK-801 and NBQX. Glutamate injections alone had no effect on striatal metabolism, whereas NMDA and AMPA injections increased [14C]-2-deoxyglucose uptake.

CONCLUSIONS

The data imply that glutamate activation of NMDA or AMPA receptors increases glucose metabolism in perihematomal brain at early times after intracerebral hemorrhage. This may provide a possible target for the treatment of intracerebral hemorrhage.

The use of positron emission tomography in cerebrovascular disease

Even with rapid development of other neuroimaging modalities such as MR imaging and CT, PET is the only technique that provides accurate, quantitative measurements of regional hemodynamics and metabolism in human subjects. Through the use of these combined measurements, we have greatly expanded our knowledge of the pathophysiology of cerebrovascular disease of different types. It has been possible to document the compensatory responses of the brain to reductions in perfusion pressure and to directly relate these responses to prognosis. PET measurements of OEF identify a subgroup of patients who have carotid occlusion and who are at increased risk for recurrent stroke who cannot be identified by any other clinical or arteriographic means. These measurements of OEF are being used to identify high-risk patients for inclusion in a clinical trial to assess the efficacy of surgical revascularization in reducing the subsequence of ipsilateral ischemic stroke. In acute ischemic stroke, attempts have been made to define the "ischemic penumbra" and to predict tissue viability and clinical outcome, although the reliability of PET markers of ischemia in distinguishing viable from irreversibly damaged tissue needs to be confirmed with independent data sets. Much work has been devoted to the investigation of the metabolic effects of infarcts and hemorrhages on remote areas of the brain; the clinical importance of such findings appears to be minimal. Early studies of recovery from stroke suggested functional reorganization of the brain, but further investigations with more rigorous experimental design need to be performed. Given the case of performing such studies with functional MR imaging, it is likely that this technology will supplant PET for this specific indication. The importance of ischemia as a secondary mechanism of brain injury has been addressed in ICH and SAH. PET demonstrated that hematomas exert a primary depression of metabolism rather than inducing ischemia in the surrounding tissue. It also documented the integrity of autoregulation and provided clinically useful information regarding the safety of blood pressure reduction after ICH. Studies in SAH have differentiated the primary effects of the hemorrhage on cerebral hemodynamics and metabolism from those of vasospasm. PET studies are time-consuming, expensive, and require extensive facilities and technical support. In the field of cerebrovascular disease, PET has served as a specialized research tool at a few centers to help elucidate the pathophysiology of stroke. Up until now, however, PET scans in individual patients have not been demonstrated to be necessary for making patient care decisions. Whether the role of PET expands to impact the management of individual patients will depend on the results of investigations like the Carotid Occlusion Surgery Study that directly assess the ability of PET to influence patient outcome.