Management of delayed cerebral ischemia after subarachnoid hemorrhage

Intracranial Aneurysms and Lipid Metabolism Disorders: From Molecular Mechanisms to Clinical Implications

Many vascular diseases are linked to lipid metabolism disorders, which cause lipid accumulation and peroxidation in the vascular wall. These processes lead to degenerative changes in the vessel, such as phenotypic transformation of smooth muscle cells and dysfunction and apoptosis of endothelial cells. In intracranial aneurysms, the coexistence of lipid plaques is often observed, indicating localized lipid metabolism disorders. These disorders may impair the function of the vascular wall or result from it. We summarize the literature on the relationship between lipid metabolism disorders and intracranial aneurysms below.

Clinicians' preferences for managing aneurysmal subarachnoid hemorrhage using endothelin receptor antagonists

Background

The endothelin receptor antagonist (ERA) clazosentan is being investigated for the medical prevention of cerebral vasospasm and associated complications, such as delayed cerebral ischemia (DCI), after aneurysmal subarachnoid hemorrhage (aSAH). This study quantified how clinicians weigh the benefits and risks of ERAs for DCI prevention to better understand their treatment needs and expectations.

Methods

An online choice experiment was conducted to elicit preferences of neurologists, intensivists, and neurosurgeons treating aSAH in the US and UK for the use of ERAs. The design of the choice experiment was informed by a feasibility assessment (N = 100), one-on-one interviews with clinicians (N = 10), a qualitative pilot (N = 13), and a quantitative pilot (N = 50). Selected treatment attributes included in the choice experiment were: one benefit (likelihood of DCI); and three risks (lung complications, hypotension, and anemia). In the choice experiment, clinicians repeatedly chose best and worst treatment options based on a scenario of a patient being treated in the ICU after aneurism repair. A correlated mixed logit model determined the relative attribute importance (RAI) and associated highest density interval (HDI) as well as acceptable benefit-risk trade-offs.

Results

The final choice experiment was completed by 350 clinicians (116 neurologists, 129 intensivists/intensive care clinicians, and 105 neurosurgeons; mean age, 47.4 years). Reducing the likelihood of DCI (RAI = 56.5% [HDI, 53.6-59.5%]) had the largest impact on clinicians' treatment choices, followed by avoiding the risks of lung complications (RAI = 29.6% [HDI, 27.1-32.3%]), hypotension (RAI = 9.2% [HDI, 7.5-10.8%]), and anemia (RAI = 4.7% [HDI, 3.7-5.8%]). Clinicians expected the likelihood of DCI to decrease by ≥8.1% for a 20% increase in the risk of lung complications, ≥2.4% for a 20% increase in the risk of hypotension, and ≥1.2% for a 20% increase in the risk of anemia.

Conclusions

Clinicians were willing to accept certain increased risks of adverse events for a reduced risk of DCI after aSAH. The likelihood of DCI occurring after aSAH can therefore be considered a clinically relevant endpoint in aSAH treatment development. Thus, evaluations of ERAs might focus on whether improvements (i.e., reductions) in the likelihood of DCI justify the risks of adverse events.

Interventions for altering blood pressure in people with acute subarachnoid haemorrhage

BACKGROUND

Subarachnoid haemorrhage has an incidence of up to nine per 100,000 person-years. It carries a mortality of 30% to 45% and leaves 20% dependent in activities of daily living. The major causes of death or disability after the haemorrhage are delayed cerebral ischaemia and rebleeding. Interventions aimed at lowering blood pressure may reduce the risk of rebleeding, while the induction of hypertension may reduce the risk of delayed cerebral ischaemia. Despite the fact that medical alteration of blood pressure has been clinical practice for more than three decades, no previous systematic reviews have assessed the beneficial and harmful effects of altering blood pressure (induced hypertension or lowered blood pressure) in people with acute subarachnoid haemorrhage.

OBJECTIVES

To assess the beneficial and harmful effects of altering arterial blood pressure (induced hypertension or lowered blood pressure) in people with acute subarachnoid haemorrhage.

SEARCH METHODS

We searched the following from inception to 8 September 2020 (Chinese databases to 27 January 2019): Cochrane Stroke Group Trials register; CENTRAL; MEDLINE; Embase; five other databases, and five trial registries. We screened reference lists of review articles and relevant randomised clinical trials.

SELECTION CRITERIA

Randomised clinical trials assessing the effects of inducing hypertension or lowering blood pressure in people with acute subarachnoid haemorrhage. We included trials irrespective of publication type, status, date, and language.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. We assessed the risk of bias of all included trials to control for the risk of systematic errors. We performed trial sequential analysis to control for the risks of random errors. We also applied GRADE. Our primary outcomes were death from all causes and death or dependency. Our secondary outcomes were serious adverse events, quality of life, rebleeding, delayed cerebral ischaemia, and hydrocephalus. We assessed all outcomes closest to three months' follow-up (primary point of interest) and maximum follow-up.

MAIN RESULTS

We included three trials: two trials randomising 61 participants to induced hypertension versus no intervention, and one trial randomising 224 participants to lowered blood pressure versus placebo. All trials were at high risk of bias. The certainty of the evidence was very low for all outcomes. Induced hypertension versus control Two trials randomised participants to induced hypertension versus no intervention. Meta-analysis showed no evidence of a difference between induced hypertension versus no intervention on death from all causes (risk ratio (RR) 1.60, 95% confidence interval (CI) 0.57 to 4.42; P = 0.38; I2 = 0%; 2 trials, 61 participants; very low-certainty evidence). Trial sequential analyses showed that we had insufficient information to confirm or reject our predefined relative risk reduction of 20% or more. Meta-analysis showed no evidence of a difference between induced hypertension versus no intervention on death or dependency (RR 1.29, 95% CI 0.78 to 2.13; P = 0.33; I2 = 0%; 2 trials, 61 participants; very low-certainty evidence). Trial sequential analyses showed that we had insufficient information to confirm or reject our predefined relative risk reduction of 20% or more. Meta-analysis showed no evidence of a difference between induced hypertension and control on serious adverse events (RR 2.24, 95% CI 1.01 to 4.99; P = 0.05; I2 = 0%; 2 trials, 61 participants; very low-certainty evidence). Trial sequential analysis showed that we had insufficient information to confirm or reject our predefined relative risk reduction of 20% or more. One trial (41 participants) reported quality of life using the Stroke Specific Quality of Life Scale. The induced hypertension group had a median of 47 points (interquartile range 35 to 55) and the no-intervention group had a median of 49 points (interquartile range 35 to 55). The certainty of evidence was very low. One trial (41 participants) reported rebleeding. Fisher's exact test (P = 1.0) showed no evidence of a difference between induced hypertension and no intervention on rebleeding. The certainty of evidence was very low. Trial sequential analysis showed that we had insufficient information to confirm or reject our predefined relative risk reduction of 20% or more. One trial (20 participants) reported delayed cerebral ischaemia. Fisher's exact test (P = 1.0) showed no evidence of a difference between induced hypertension and no intervention on delayed cerebral ischaemia. The certainty of the evidence was very low. Trial sequential analysis showed that we had insufficient information to confirm or reject our predefined relative risk reduction of 20% or more. None of the trials randomising participants to induced hypertension versus no intervention reported on hydrocephalus. No subgroup analyses could be conducted for trials randomising participants to induced hypertension versus no intervention. Lowered blood pressure versus control One trial randomised 224 participants to lowered blood pressure versus placebo. The trial only reported on death from all causes. Fisher's exact test (P = 0.058) showed no evidence of a difference between lowered blood pressure versus placebo on death from all causes. The certainty of evidence was very low.

AUTHORS' CONCLUSIONS

Based on the current evidence, there is a lack of information needed to confirm or reject minimally important intervention effects on patient-important outcomes for both induced hypertension and lowered blood pressure. There is an urgent need for trials assessing the effects of altering blood pressure in people with acute subarachnoid haemorrhage. Such trials should use the SPIRIT statement for their design and the CONSORT statement for their reporting. Moreover, such trials should use methods allowing for blinded altering of blood pressure and report on patient-important outcomes such as mortality, rebleeding, delayed cerebral ischaemia, quality of life, hydrocephalus, and serious adverse events.

Relationship of the vascular territory affected by delayed cerebral ischemia and the location of the ruptured aneurysm in patients with aneurysmal subarachnoid hemorrhage

OBJECTIVE

To determine the area most at risk of delayed cerebral ischemia (DCI) in relation to the location of the ruptured aneurysm in patients with aneurysmal subarachnoid hemorrhage (aSAH) and, therefore, help to choose the site for focal multimodal neuromonitoring.

METHODS

We retrospectively analyzed angiographic findings, CCT scans, and patient charts of patients who were admitted with aSAH to our neurosurgical intensive care unit between 2009 and 2017. DCI was defined as infarction on CCT 2-6 weeks after aSAH.

RESULTS

DCI occurred in 17.9% out of 357 included patients. A DCI occurring in the vascular territory of the artery carrying the ruptured aneurysm was found in 81.0% of patients with anterior circulation aneurysms but only in 16.7% with posterior circulation aneurysms (Fisher's exact, p=0.003). The vascular territory most frequently showing a DCI was the ipsilateral MCA territory (86.7%) in ICA aneurysms, the contra- (71.4%) and the ipsilateral (64.3%) ACA territory in ACA aneurysms, the right (93.8%) and the left (81.3%) ACA territory in AcomA aneurysms, and the ipsilateral MCA territory in MCA aneurysms (69.2%) as well as in VA/PICA/SCA aneurysms (100.0%). DCI after the rupture of a BA aneurysm occurred with 33.3% in 6 out of 8 vascular territories, respectively. DCI of multiple vascular territories occurred in 100.0% of BA aneurysms, 87.5% of AcomA aneurysms, 71.4% of ACA aneurysms, 40.0% of ICA aneurysms, 38.5% of MCA aneurysms, and 33.3% of VA/PICA/SCA aneurysms.

DISCUSSION

Few studies exist that could determine the area most at risk of a DCI after an aSAH. Our data could identify the territory most at risk for DCI with a probability of > 60% except for BA aneurysms, which showed DCI in various areas and patients suffering from multiple DCIs. Either the ipsilateral ACA or MCA were affected by the DCI in about 80% of ACA and more than 90% of AcomA, ICA, MCA, and VA/PICA/SCA aneurysms. Therefore, local intraparenchymal neuromonitoring in the ACA/MCA watershed area might detect the vast majority of DCIs for all aneurysm locations, except for BA aneurysms. In ACA and AcomA aneurysms, bilateral DCI of the ACA territory was common, and bilateral probe positioning might be considered for monitoring high-risk patients. Non-focal monitoring methods might be preferably used after BA aneurysm rupture.

Pharmaceutical Management for Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage can have deleterious consequences. Vasospasm, delayed cerebral ischemia, and re-hemorrhage can all cause delayed sequelae. Furthermore, severe headaches are common and require careful modulation of pain medications. Limited treatment options currently exist and are becoming more complex with the rising use of oral anticoagulants needing reversal. In this review, we highlight the current treatment options currently employed and address avenues of future discovery based on emerging preclinical data. Furthermore, we dive into the best treatment approach for managing headaches following subarachnoid hemorrhage. The review is designed to serve as a catalyst for further prospective investigation into this important topic.

Approach to the Diagnosis and Management of Subarachnoid Hemorrhage

Headache is one of the most common reasons for presentation to the emergency department (ED), seen in up to 2% of patients.1 Most are benign, but it is imperative to understand and discern the life-threatening causes of headache when they present. Headache caused by a subarachnoid hemorrhage (SAH) from a ruptured aneurysm is one of the most deadly, with a median case-fatality of 27–44%.2 Fortunately, it is also rare, comprising only 1% of all headaches presenting to the ED.3 On initial presentation, the one-year mortality of untreated SAH is up to 65%.4 With appropriate diagnosis and treatment, mortality can be reduced to 18%.5 The implications are profound: Our careful assessment leading to the detection of a SAH as the cause of headache can significantly decrease our patients’ mortality. If this were an easy task, the 12% reported rate of missed diagnosis would not exist.6 We have multiple tools and strategies to evaluate the patient with severe headache and must understand the strengths and limitations of each tool. Herein we will describe the available strategies, as well as the ED management of the patient with SAH.

Vasospasm following aneurysmal subarachnoid hemorrhage: prediction, detection, and intervention

Background

Vasospasm of the cerebral blood vessels is a common complication of aneurysmal subarachnoid hemorrhage (aSAH) which results in delayed cerebral ischemia (DCI) and worsening of the outcome.

Methods

This study was performed on 41 aSAH patients diagnosed by non-contrast brain CT, CT angiography, and digital subtraction angiography followed by interventional aneurysmal embolization. Patients were followed up for 20 days by clinical assessment, EEG monitoring, and transcranial duplex studies (TCD) for early detection of vasospasm and DCI.

Results

The most common ruptured aneurysmal sites were middle cerebral, anterior communicating, posterior communicating, terminal internal carotid, and anterior cerebral arteries respectively. The incidence of vasospasm was 36.8% of the included cases; 57% progressed to DCI while 43% passed a spontaneous regressive course. The most common arteries undergoing vasospasm were the MCA followed by the ACA, ICA, and lastly the basilar arteries. The mean time of vasospasm development as detected by EEG monitoring and/or TCD was 8.4 ± 2.8 days which was earlier than clinical signs by 12.5 ± 5.3 h in those progressed to DCI.

Conclusion

Continuous EEG monitoring and TCD are valuable methods for early detection of vasospasm and they allow for early therapeutic intervention before irreversible ischemic neurological deficits take place.

The profile of blunt traumatic infratentorial cranial bleed types

Infratentorial traumatic intracranial bleeds (ICBs) are rare and the distribution of subtypes is unknown. To characterize this distribution the National Trauma Data Bank (NTDB) 2014 was queried for adults with single type infratentorial ICB, n = 1,821: subdural hemorrhage (SDH), subarachnoid hemorrhage (SAH), epidural hemorrhage (EDH), and intraparenchymal hemorrhage (IPH). Comparisons were made between the groups with statistical significance determined using chi squared and t-tests. SDH occurred in 29% of patients, mostly in elderly on anti-coagulants (13%) after a fall (77%), 42% of them underwent craniotomy, their mortality was the lowest (4%). SAH was the most common (56%) occurring mostly from traffic related injuries (27%). Furthermore, 9% of them had a severe head injury Glasgow Coma Scale ≤8 (GCS), but had the lowest Injury Severity Score (ISS, median 8) as well as a short hospital length of stay, 5.1 ± 6.2 days. These patients were most likely to be discharged to home (64%). They had the lowest mortality (4%). EDH was the least common ICB (5%), occurred in younger patients (median age 49 years), and it had the highest percentage of associated injuries (13%). EDH patients presented with the poorest neurological status (26% GCS ≤8, ISS median 25) and were operated on more than any other ICB type (55%). EDH was the highest mortality (9%) ICB type and had a low discharge to home rate (58%). IPH was uncommon (10%). Infratentorial bleeds types have different clinical courses, and outcomes. Understanding these differences can be useful in managing these patients.

Continuous EEG Monitoring for Early Detection of Delayed Cerebral Ischemia in Subarachnoid Hemorrhage: A Pilot Study

INTRODUCTION

Early identification of delayed cerebral ischemia (DCI) in patients with aneurysmal subarachnoid hemorrhage (aSAH) is a major challenge. The aim of this study was to investigate whether quantitative EEG (qEEG) features can detect DCI prior to clinical or radiographic findings.

METHODS

A prospective cohort study was performed in aSAH patients in whom continuous EEG (cEEG) was recorded. We studied 12 qEEG features. We compared the time point at which qEEG changed with the time point that clinical deterioration occurred or new ischemia was noted on CT scan.

RESULTS

Twenty aSAH patients were included of whom 11 developed DCI. The alpha/delta ratio (ADR) was the most promising feature that showed a significant difference in change over time in the DCI group (median -62% with IQR -87 to -39%) compared to the control group (median +27% with IQR -32 to +104%, p = 0.013). Based on the ROC curve, a threshold was chosen for a combined measure of ADR and alpha variability (AUC: 91.7, 95% CI 74.2-100). The median time that elapsed between change of qEEG and clinical DCI diagnosis was seven hours (IQR -11-25). Delay between qEEG and CT scan changes was 44 h (median, IQR 14-117).

CONCLUSION

In this study, ADR and alpha variability could detect DCI development before ischemic changes on CT scan was apparent and before clinical deterioration was noted. Implementation of cEEG in aSAH patients can probably improve early detection of DCI.

Intra-arterial nimodipine for cerebral vasospasm after subarachnoid haemorrhage: Influence on clinical course and predictors of clinical outcome

Intra-arterial nimodipine (IAN) has shown a promising effect on cerebral vasospasm (CV) after aneurysmal subarachnoid haemorrhage. At our institution, Rigshospitalet, IAN treatment has been used since 2009, but the short- and long-term clinical efficacy of IAN has not yet been assessed. The purpose was to evaluate the efficacy and clinical outcome of IAN treatment of symptomatic CV, and to assess the predictors of clinical outcome. Medical records of 25 patients undergoing a total of 41 IAN treatment sessions were retrospectively reviewed. Data on angiographic results, blood-flow velocities and the clinical condition before and after the IAN treatment were recorded. Predictors of the clinical outcome were assessed with a linear regression model. Positive angiographic response was achieved in 95.1% of 41 IAN treatment sessions. Flow-velocity measurements showed no relationship with angiographic responses of IAN. The immediate clinical improvement was observed in three patients (12%). Five patients (20%) had a favourable outcome at discharge and at three-month follow-up; 10 patients (40%) had a moderate to poor outcome; and the rest (40%) died. Increased number of affected vessels and number of procedures carried out per patient, and a trend toward an increased delay time from symptomatic CV to confirming angiographic CV and thus instituting IAN treatment predicted the poor clinical outcome. IAN treatment appears to be effective in reversing angiographic CV. However, it is not always effective in reversing clinical deterioration, as several other factors including treatment delay affect the clinical course.

Long-term functional consequences and ongoing cerebral inflammation after subarachnoid hemorrhage in the rat

Subarachnoid hemorrhage (SAH) represents a considerable health problem with an incidence of 6–7 per 100.000 individuals per year in Western society. We investigated the long-term consequences of SAH on behavior, neuroinflammation and gray- and white-matter damage using an endovascular puncture model in Wistar rats. Rats were divided into a mild or severe SAH group based on their acute neurological score at 24 h post-SAH. The degree of hemorrhage determined in post-mortem brains at 48 h strongly correlated with the acute neurological score. Severe SAH induced increased TNF-α, IL-1β, IL-10, MCP-1, MIP2, CINC-1 mRNA expression and cortical neutrophil influx at 48 h post-insult. Neuroinflammation after SAH was very long-lasting and still present at day 21 as determined by Iba-1 staining (microglia/macrophages) and GFAP (astrocytes). Long-term neuroinflammation was strongly associated with the degree of severity of SAH. Cerebral damage to gray- and white-matter was visualized by immunohistochemistry for MAP2 and MBP at 21 days after SAH. Severe SAH induced significant gray- and white-matter damage. MAP2 loss at day 21 correlated significantly with the acute neurological score determined at 24 h post-SAH. Sensorimotor behavior, determined by the adhesive removal task and von Frey test, was affected after severe SAH at day 21. In conclusion, we are the first to show that SAH induces ongoing cortical inflammation. Moreover, SAH induces mainly cortical long-term brain damage, which is associated with long-term sensorimotor damage.