Effect of cilostazol in patients with aneurysmal subarachnoid hemorrhage: A systematic review and meta-analysis

Fasudil hydrochloride and ozagrel sodium combination therapy for patients with aneurysmal subarachnoid hemorrhage: a cross-sectional study using a nationwide inpatient database

BACKGROUND

Fasudil and ozagrel are drugs with the same indications for the treatment of cerebral vasospasm in Japan. However, there have been no definitive conclusions on the clinical efficacy of fasudil hydrochloride and ozagrel sodium monotherapy or their combination. Therefore, we aimed to investigate the effectiveness of the combined administration of fasudil hydrochloride and ozagrel sodium in Japanese patients with subarachnoid hemorrhage (SAH).

METHODS

This cross-sectional study used Diagnosis Procedure Combination data to assess patients who were hospitalized with SAH and received fasudil hydrochloride or ozagrel sodium between April 2016 and March 2020 (n = 17,346). The participants were divided into three groups based on the treatment received: fasudil hydrochloride monotherapy (F group, n = 10,484), ozagrel sodium monotherapy (O group, n = 465), and fasudil hydrochloride and ozagrel sodium combination therapy (FO group, n = 6,397). The primary outcome was in-hospital mortality. Multivariable adjusted logistic regression analysis (significance level, 5%) was used for data analyses.

RESULTS

The results of the multivariable analysis, adjusted for factors considered to impact prognosis, showed that the adjusted odds ratio (OR) with the F group as the reference for in-hospital mortality was 0.94 in the FO group (95% confidence interval [CI]: 0.81-1.08, p = 0.355), with no differences compared to the F group.

CONCLUSION

Fasudil hydrochloride and ozagrel sodium had different mechanisms of action, suggesting a synergistic effect of combination therapy. However, a comparison of fasudil hydrochloride monotherapy and combination therapy of fasudil hydrochloride and ozagrel sodium showed no difference in the prognostic effect. Therefore, it was suggested that fasudil hydrochloride monotherapy may be sufficient.

Factors Affecting Outcomes of Poor-Grade Subarachnoid Hemorrhage

OBJECTIVE

Poor-grade subarachnoid hemorrhage (SAH) accounts for 20% of all SAH and is associated with poor outcomes. The first step in improving outcomes is to analyze the factors that contribute to poor outcomes.

METHODS

This was a multicenter, retrospective, observational, cohort study. Data fields included demographic, clinical, radiological, and outcome data for all spontaneous patients with SAH treated at 4 hospitals in Aomori Prefecture in Japan. Patients with modified Rankin Scale score 0-2 at discharge were defined as the good outcome group, and those with modified Rankin Scale score 3-6 were defined as the poor outcome group, and comparisons were made between the 2 groups.

RESULTS

There were 329 eligible patients with poor-grade SAH, 41 with good outcome group, and 288 with poor outcome group. On multivariate analysis of the outcome, conservative treatment (P < 0.001), Fisher group 4 (P < 0.007), age ≥65 years (P = 0.011), and Hunt and Kosnik grade V on admission (P = 0.021) were significant factors contributing to a poor outcome.

CONCLUSIONS

Nonelderly patients who are not in grade V and Fisher group 4 should undergo aneurysm treatment as soon as possible because they are more likely to have a good outcome, whereas elderly patients in grade V and Fisher group 4 are unlikely to benefit from aneurysm treatment at present. The development of a treatment for early brain injury may be important to improve the outcomes of patients with poor-grade SAH.

Japanese nationwide questionnaire survey on delayed cerebral infarction due to vasospasm after subarachnoid hemorrhage

Background and purpose

Various prophylactic drugs for cerebral vasospasm and delayed cerebral infarction (DCI) after subarachnoid hemorrhage (SAH) have been used in Japan. To investigate the treatment trends for cerebral vasospasm and frequency of DCI after SAH throughout Japan in 2021.

Methods

In 2021 we conducted an anonymous questionnaire survey on management for preventing cerebral vasospasm after aneurysmal SAH, and the frequency of DCI. The questionnaire was emailed to 955 certified neurosurgeons at 553 hospitals in Japan. Of them, 162 hospitals (29% response rate) responded to the questionnaire. Of these, 158 were included in this study, while four hospitals that responded insufficiently were excluded. The efficacy of treatments for reducing DCI were examined through a logistic regression analysis.

Results

Among 3,093 patients treated with aneurysmal SAH, 281 patients (9.1%) were diagnosed with DCI related to cerebral vasospasm. Coil embolization had significantly lower DCI frequency (6.9%), compared to microsurgical clipping (11.8%, odds ratio, 0.90; 95% confidential intervals, 0.84-0.96; P, 0.007). In addition, cilostazol administration was associated with significantly lower DCI frequency (0.48; 0.27-0.82; 0.026). The efficacy of cilostazol in reducing DCI remained unchanged after adjustment for covariates. The most effective combination of multiple prophylactic drugs in reducing DCI related to cerebral vasospasm was cilostazol, fasudil, and statin (0.38; 0.22-0.67; 0.005).

Conclusions

This study elucidated the trends in prophylactic drugs to prevent cerebral vasospasm and frequency of DCI after aneurysmal SAH in Japan. Coil embolization and cilostazol administration showed effectiveness in reducing DCI related to cerebral vasospasm in 2021.

Effects of cilostazol treatment for patients with aneurysmal subarachnoid hemorrhage: A meta-analysis of 14 studies

OBJECTIVE

To perform an updated meta-analysis to comprehensively assess the efficacy and safety of cilostazol in preventing aneurysmal subarachnoid hemorrhage (SAH)-related secondary complications.

METHODS

Electronic databases of PubMed, the Cochrane library, CNKI and Wanfang were searched on August 2021. Pooled odds ratio (OR) and standardized mean difference (SMD) were calculated for dichotomous and continuous outcomes, respectively.

RESULTS

A total of 14 studies [comprising 18,726 aneurysmal SAH patients (6654 in the cilostazol group and 12,072 in the control group)] performed in Japan or China were included. Compared with the control group, cilostazol treatment significantly reduced the median cerebral artery (SMD = -0.49; p < 0.001), improved the therapeutic efficacy (OR = 2.37; p = 0.009), decreased the incidence of symptomatic vasospasm/delayed cerebral ischemia (OR = 0.42; p < 0.001), severe angiographic vasospasm (OR = 0.54; p < 0.001), new cerebral infarction (OR = 0.33; p < 0.001), poor outcomes (OR = 0.86; p = 0.001), mortality (OR = 0.62; p < 0.001) and increased the incidence of no or mild angiographic vasospasm (OR = 1.94; p = 0.004), but did not induce more adverse events (OR = 1.08; p = 0.871). The mechanism of cilostazol treatment was to inhibit the production of tenascin-C (SMD = -1.46; p < 0.001). These results were hardly changed by subgroup analysis.

CONCLUSION

This meta-analysis indicates cilostazol may be an effective and safe drug for aneurysmal SAH patients. However, further trials involving other world populations are required to demonstrate the generalization of treatment effects of cilostazol.

Sex Differences in Cerebral Aneurysms and Subarachnoid Hemorrhage

Sex differences in cerebral aneurysm occurrence and characteristics have been well described. Although sex differences in outcomes following ischemic stroke have been identified, the effect of sex on outcomes following hemorrhagic stroke, and in particular, aneurysm treatment has been less studied. We describe the current state of knowledge regarding the impact of sex on treatment and outcomes of cerebral aneurysms. Although prior studies suggest that aneurysm prevalence and progression may be related to sex, we did not find clear evidence that outcomes following subarachnoid hemorrhage vary based on sex. Last, we identify areas for future research that could enhance understanding of the role sex plays in this context.

Cilostazol administration for subarachnoid hemorrhage: A meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy of cilostazol administration to treat subarachnoid hemorrhage remains controversial. We conduct a systematic review and meta-analysis to explore the influence of cilostazol administration on treatment efficacy for subarachnoid hemorrhage.

METHODS

We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through July 2020 for randomized controlled trials (RCTs) assessing the effect of cilostazol administration in patients with subarachnoid hemorrhage. This meta-analysis is performed using the random-effect model.

RESULTS

Four RCTs involving 405 patients were included in the meta-analysis. Overall, compared with control group for subarachnoid hemorrhage, cilostazol intervention can significantly reduce symptomatic vasospasm (OR = 0.35; 95% CI = 0.21 to 0.60; P = 0.0001) and cerebral infarction (OR = 0.40; 95% CI = 0.22 to 0.73; P = 0.003), as well as improve no or mild angiographic vasospasm (OR = 2.01; 95% CI = 1.19 to 3.42; P = 0.01) and mRS score ≤ 2 (OR = 2.70; 95% CI = 1.09 to 6.71; P = 0.03), but revealed no obvious influence on severe angiographic vasospasm (OR = 0.53; 95% CI = 0.27 to 1.02; P = 0.06). There were no increase in adverse events (OR = 1.17; 95% CI = 0.54 to 2.52; P = 0.69), hemorrhagic events (OR = 0.62; 95% CI = 0.06 to 6.27; P = 0.69) and cardiac events (OR = 2.14; 95% CI = 0.44 to 10.27; P = 0.34) after the cilostazol intervention than control intervention.

CONCLUSIONS

Cilostazol treatment may be effective to treat subarachnoid hemorrhage in the terms of symptomatic vasospasm, cerebral infarction, no or mild angiographic vasospasm and mRS score ≤ 2.

Role of Cilostazol in Prevention of Vasospasm After Aneurysmal Subarachnoid Hemorrhage-A Systematic Review, Meta-Analysis, and Trial Sequential Analysis

OBJECTIVE

Cerebral vasospasm is a common complication after aneurysmal subarachnoid hemorrhage (aSAH). Many drugs have been tried to mitigate cerebral vasospasm and delayed cerebral ischemia. Cilostazol, a selective inhibitor of phosphodiesterase 3, is a promising agent in preventing cerebral vasospasm and delayed cerebral ischemia after aSAH. The objective of this article was to ascertain the effect of cilostazol on cerebral vasospasm after aSAH by performing meta-analysis and trial sequential analysis.

METHODS

A systematic search of the literature was performed, and all the eligible randomized controlled trials were included in the meta-analysis and trial sequential analysis.

RESULTS

A total of 454 articles were identified using the search criteria. Six articles were selected for systematic review and the 4 randomized controlled trials were included in the meta-analysis. The pooled odds ratio for symptomatic vasospasm, new-onset infarct, and angiographic vasospasm was 0.35 (95% confidence interval [CI], 0.21-0.59; P < 0.0001), 0.38 (95% CI, 0.21-0.66; P = 0.0007) and 0.49 (95% CI, 0.31-0.80; P = 0.004), respectively. The pooled risk ratio for unfavorable outcome was 0.52 (95% CI, 0.37-0.74; P = 0.0003).

CONCLUSIONS

Cilostazol decreases the prevalence of symptomatic vasospasm, new-onset infarct, and angiographic vasospasm when administered after aSAH. Trial sequential analysis increased the precision of our results because the defined thresholds of effect were met by the available studies. However, further studies involving patients from other geographic areas are required to confirm the generalization of the results.

The Updated Role of the Blood Brain Barrier in Subarachnoid Hemorrhage: From Basic and Clinical Studies

Subarachnoid hemorrhage (SAH) is a type of hemorrhagic stroke associated with high mortality and morbidity. The blood-brain-barrier (BBB) is a structure consisting primarily of cerebral microvascular endothelial cells, end feet of astrocytes, extracellular matrix, and pericytes. Post-SAH pathophysiology included early brain injury and delayed cerebral ischemia. BBB disruption was a critical mechanism of early brain injury and was associated with other pathophysiological events. These pathophysiological events may propel the development of secondary brain injury, known as delayed cerebral ischemia. Imaging advancements to measure BBB after SAH primarily focused on exploring innovative methods to predict clinical outcome, delayed cerebral ischemia, and delayed infarction related to delayed cerebral ischemia in acute periods. These predictions are based on detecting abnormal changes in BBB permeability. The parameters of BBB permeability are described by changes in computed tomography (CT) perfusion and magnetic resonance imaging (MRI). K_ep seems to be a stable and sensitive indicator in CT perfusion, whereas K^trans is a reliable parameter for dynamic contrast-enhanced MRI. Future prediction models that utilize both the volume of BBB disruption and stable parameters of BBB may be a promising direction to develop practical clinical tools. These tools could provide greater accuracy in predicting clinical outcome and risk of deterioration. Therapeutic interventional exploration targeting BBB disruption is also promising, considering the extended duration of post-SAH BBB disruption.

Therapeutic Potential of Heme Oxygenase-1 in Aneurysmal Diseases

Abdominal aortic aneurysm (AAA) and intracranial aneurysm (IA) are serious arterial diseases in the aorta and brain, respectively. AAA and IA are associated with old age in males and females, respectively, and if rupture occurs, they carry high morbidity and mortality. Aneurysmal subarachnoid hemorrhage (SAH) due to IA rupture has a high rate of complication and fatality. Despite these severe clinical outcomes, preventing or treating these devastating diseases remains an unmet medical need. Inflammation and oxidative stress are shared pathologies of these vascular diseases. Therefore, therapeutic strategies have focused on reducing inflammation and reactive oxygen species levels. Interestingly, in response to cellular stress, the inducible heme oxygenase-1 (HO-1) is highly upregulated and protects against tissue injury. HO-1 degrades the prooxidant heme and generates molecules with antioxidative and anti-inflammatory properties, resulting in decreased oxidative stress and inflammation. Therefore, increasing HO-1 activity is an attractive option for therapy. Several HO-1 inducers have been identified and tested in animal models for preventing or alleviating AAA, IA, and SAH. However, clinical trials have shown conflicting results. Further research and the development of highly selective HO-1 regulators may be needed to prevent the initiation and progression of AAA, IA, or SAH.

Molecular targets in cerebral malaria for developing novel therapeutic strategies

Cerebral malaria (CM) is the severe neurological complication associated with Plasmodium falciparum infection. In clinical settings CM is predominantly characterized by fever, epileptic seizures, and asexual forms of parasite on blood smears, coma and even death. Cognitive impairment in the children and adults even after survival is one of the striking consequences of CM. Poor diagnosis often leads to inappropriate malaria therapy which in turn progress into a severe form of disease. Activation of multiple cell death pathways such as Inflammation, oxidative stress, apoptosis and disruption of blood brain barrier (BBB) plays critical role in the pathogenesis of CM and secondary brain damage. Thus, understanding such mechanisms of neuronal cell death might help to identify potential molecular targets for CM. Mitigation strategies for mortality rate and long-term cognitive deficits caused by existing anti-malarial drugs still remains a valid research question to ask. In this review, we discuss in detail about critical neuronal cell death mechanisms and the overall significance of adjunctive therapy with recent trends, which provides better insight towards establishing newer therapeutic strategies for CM.

A Review of the Management of Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Despite decades of research, cerebral vasospasm (CV) continues to account for high morbidity and mortality in patients who survive their initial aneurysmal subarachnoid hemorrhage.

OBJECTIVE

To define the scope of the problem and review key treatment strategies that have shaped the way CV is managed in the contemporary era.

METHODS

A literature search was performed of CV management after aneurysmal subarachnoid hemorrhage.

RESULTS

Recent advances in neuroimaging have led to improved detection of vasospasm, but established treatment guidelines including hemodynamic augmentation and interventional procedures remain highly variable among neurosurgical centers. Experimental research in subarachnoid hemorrhage continues to identify novel targets for therapy.

CONCLUSIONS

Proactive and preventive strategies such as oral nimodipine and endovascular rescue therapies can reduce the morbidity and mortality associated with CV.

Periprocedural Neuroendovascular Antiplatelet Strategies for Thrombosis Prevention in Clopidogrel-Hyporesponsive Patients

Patients undergoing neuroendovascular procedures such as cerebral aneurysm coiling and intracranial stent deployment are frequently treated with antiplatelet agents to prevent thrombotic complications. The combination of aspirin and a P2Y12 inhibitor such as clopidogrel is often initiated days before elective procedures or as loading doses for emergent procedures; however, some patients may still experience thrombotic complications. Patients identified as clopidogrel hyporesponders are more likely to experience poor outcomes and may require changes to their regimens. Historically, high-dose clopidogrel regimens were used in response to subtherapeutic results of platelet function assays and point-of-care testing despite limited supporting data. Recently, more data have emerged using alternative P2Y12 inhibitors such as prasugrel and ticagrelor. Dosing for neuroendovascular conditions is often extrapolated from the cardiac literature, although outcomes in cardiac patients may not be relevant to neurologic patients, making prophylactic treatment recommendations challenging for these patients. This review summarizes the literature for antiplatelet prophylaxis in patients undergoing neuroendovascular device placement, focusing on alternative regimens for clopidogrel hyporesponders.

Effectiveness and feasibility of cilostazol in patients with aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis

BACKGROUND

Delayed cerebral ischemia seriously affects the prognosis of patients surviving the initial aneurysmal subarachnoid hemorrhage. Application of cilostazol was reported to ameliorate vasospasm and improve outcomes in series and clinical trials. But the effectiveness and feasibility of cilostazol on aneurysmal subarachnoid hemorrhage remained controversial. We performed a systematic review to clarify this issue.

METHODS

PubMed, Ovid and Cochrane library database were systematically searched up to May 2018 for eligible publications in English. Quality assessment was conducted for included studies. Meta-analysis was conducted to evaluate the overall effect on events of interest. Subgroup analyses and sensitivity analyses were used to check whether the results were robust. Publication bias was evaluated with the funnel plot.

RESULTS

Pooled analyses found cilostazol significantly reduced incidences of severe angiographic vasospasm (p = 0.0001), symptomatic vasospasm (p < 0.00001), new cerebral infarction (p < 0.00001) and the poor outcome (p < 0.0001). Subgroup and sensitivity analyses achieved consistent results. There was no statistical difference between cilostazol and the control group in reducing mortality (p = 0.07). But sensitivity analysis changed the result after excluding one study. Under the prescribed dosage, complication was few and non-lethal.

CONCLUSIONS

Cilostazol was effective and safe to reduce incidences of severe angiographic vasospasm, symptomatic vasospasm, new cerebral infarction and poor outcome in patients after aneurysmal subarachnoid hemorrhage. However, its effect on mortality and the interactive effect with nimodipine warranted further research.

Cerebral vasospasm: current understanding

PURPOSE OF REVIEW

With recent research trying to explore the pathophysiologic mechanisms behind vasospasm, newer pharmacological and nonpharmacological treatments are being targeted at various pathways involved. This review is aimed at understanding the mechanisms and current and future therapies available to treat vasospasm.

RECENT FINDINGS

Computed tomography perfusion is a useful alternative tool to digital subtraction angiography to diagnose vasospasm. Various biomarkers have been tried to predict the onset of vasospasm but none seems to be helpful. Transcranial Doppler still remains a useful tool at the bedside to screen and follow up patients with vasospasm. Hypertension rather than hypervolemia and hemodilution in 'Triple-H' therapy has been found to be helpful in reversing the vasospasm. Hyperdynamic therapy in addition to hypertension has shown promising effects. Endovascular approaches with balloon angioplasty and intra-arterial nimodipine, nicardipine, and milrinone have shown consistent benefits. Endothelin receptor antagonists though relieved vasospasm, did not show any benefit on functional outcome.

SUMMARY

Endovascular therapy has shown consistent benefit in relieving vasospasm. An aggressive combination therapy through various routes seems to be the most useful approach to reduce the complications of vasospasm.

The Pathophysiology of Delayed Cerebral Ischemia

Subarachnoid hemorrhage (SAH) affects 30,000 people in the Unites States alone each year. Delayed cerebral ischemia occurs days after subarachnoid hemorrhage and represents a potentially treatable cause of morbidity for approximately one-third of those who survive the initial hemorrhage. While vasospasm has been traditionally linked to the development of cerebral ischemia several days after subarachnoid hemorrhage, emerging evidence reveals that delayed cerebral ischemia is part of a much more complicated post-subarachnoid hemorrhage syndrome. The development of delayed cerebral ischemia involves early arteriolar vasospasm with microthrombosis, perfusion mismatch and neurovascular uncoupling, spreading depolarizations, and inflammatory responses that begin at the time of the hemorrhage and evolve over time, culminating in cortical infarction. Large-vessel vasospasm is likely a late contributor to ongoing injury, and effective treatment for delayed cerebral ischemia will require improved detection of critical early pathophysiologic changes as well as therapeutic options that target multiple related pathways.

Spontaneous subarachnoid haemorrhage

Subarachnoid haemorrhage is an uncommon and severe subtype of stroke affecting patients at a mean age of 55 years, leading to loss of many years of productive life. The rupture of an intracranial aneurysm is the underlining cause in 85% of cases. Survival from aneurysmal subarachnoid haemorrhage has increased by 17% in the past few decades, probably because of better diagnosis, early aneurysm repair, prescription of nimodipine, and advanced intensive care support. Nevertheless, survivors commonly have cognitive impairments, which in turn affect patients' daily functionality, working capacity, and quality of life. Additionally, those deficits are frequently accompanied by mood disorders, fatigue, and sleep disturbances. Management requires specialised neurological intensive care units and multidisciplinary clinical expertise, which is better provided in high-volume centres. Many clinical trials have been done, but only two interventions are shown to improve outcome. Challenges that remain relate to prevention of subarachnoid haemorrhage by improved screening and development of lower-risk methods to repair or stabilise aneurysms that have not yet ruptured. Multicentre cooperative efforts might increase the knowledge that can be gained from clinical trials, which is often limited by small studies with differing criteria and endpoints that are done in single centres. Outcome assessments that incorporate finer assessment of neurocognitive function and validated surrogate imaging or biomarkers for outcome could also help to advance the specialty.

Treatment of cerebral vasospasm following aneurysmal subarachnoid haemorrhage: a systematic review and meta-analysis

OBJECTIVES

To examine the clinical outcome of aneurysmal subarachnoid haemorrhage (aSAH) patients exposed to cerebral vasospasm (CVS)-targeted treatments in a meta-analysis and to evaluate the efficacy of intra-arterial (IA) approaches in patients with severe/refractory vasospasm.

METHODS

Randomised controlled trials, prospective and retrospective observational studies reporting clinical outcomes of aSAH patients exposed to CVS targeted treatments, published between 2006-2016 were searched using PubMed, EMBASE and the Cochrane Library. The main endpoint was the proportion of unfavourable outcomes, defined as a modified Rankin score of 3-6 at last follow-up.

RESULTS

Sixty-two studies, including 26 randomised controlled trials, were included (8,976 patients). At last follow-up 2,490 of the 8,976 patients had an unfavourable outcome, including death (random-effect weighted-average, 33.7%; 99% confidence interval [CI], 28.1-39.7%; Q value, 806.0; I ² = 92.7%). The RR of unfavourable outcome was lower in patients treated with Cilostazol (RR = 0.46; 95% CI, 0.25-0.85; P = 0.001; Q value, 1.5; I ² = 0); and in refractory CVS patients treated by IA intervention (RR = 0.68; 95% CI, 0.57-0.80; P < 0.0001; number needed to treat with IA intervention, 6.2; 95% CI, 4.3-11.2) when compared with the best available medical treatment.

CONCLUSIONS

Endovascular treatment may improve the outcome of patients with severe-refractory vasospasm. Further studies are needed to confirm this result.

KEY POINTS

• 33.7% of patients with cerebral Vasospasm following aneurysmal subarachnoid-hemorrhage have an unfavorable outcome. • Refractory vasospasm patients treated using endovascular interventions have lower relative risk of unfavourable outcome. • Subarachnoid haemorrhage patients with severe vasospasm may benefit from endovascular interventions. • The relative risk of unfavourable outcome is lower in patients treated with Cilostazol.

Precision medicine of aneurysmal subarachnoid hemorrhage, vasospasm and delayed cerebral ischemia

INTRODUCTION

Precision medicine provides individualized treatment of diseases through leveraging patient-to-patient variation. Aneurysmal subarachnoid hemorrhage carries tremendous morbidity and mortality with cerebral vasospasm and delayed cerebral ischemia proving devastating and unpredictable. Lack of treatment measures for these conditions could be improved through precision medicine. Areas covered: Discussed are the pathophysiology of CV and DCI, treatment guidelines, and evidence for precision medicine used for prediction and prevention of poor outcomes following aSAH. A PubMed search was performed using keywords cerebral vasospasm or delayed cerebral ischemia and either biomarkers, precision medicine, metabolomics, proteomics, or genomics. Over 200 peer-reviewed articles were evaluated. The studies presented cover biomarkers identified as predictive markers or therapeutic targets following aSAH. Expert commentary: The biomarkers reviewed here correlate with CV, DCI, and neurologic outcomes after aSAH. Though practical use in clinical management of aSAH is not well established, using these biomarkers as predictive tools or therapeutic targets demonstrates the potential of precision medicine.

Novel Treatments in Neuroprotection for Aneurysmal Subarachnoid Hemorrhage

OPINION STATEMENT

New neuroprotective treatments aimed at preventing or minimizing "delayed brain injury" are attractive areas of investigation and hold the potential to have substantial beneficial effects on aneurysmal subarachnoid hemorrhage (aSAH) survivors. The underlying mechanisms for this "delayed brain injury" are multi-factorial and not fully understood. The most ideal treatment strategies would have the potential for a pleotropic effect positively modulating multiple implicated pathophysiological mechanisms at once. My personal management (RFJ) of patients with aneurysmal subarachnoid hemorrhage closely follows those treatment recommendations contained in modern published guidelines. However, over the last 5 years, I have also utilized a novel treatment strategy, originally developed at the University of Maryland, which consists of a 14-day continuous low-dose intravenous heparin infusion (LDIVH) beginning 12 h after securing the ruptured aneurysm. In addition to its well-known anti-coagulant properties, unfractionated heparin has potent anti-inflammatory effects and through multiple mechanisms may favorably modulate the neurotoxic and neuroinflammatory processes prominent in aneurysmal subarachnoid hemorrhage. In my personal series of patients treated with LDIVH, I have found significant preservation of neurocognitive function as measured by the Montreal Cognitive Assessment (MoCA) compared to a control cohort of my patients treated without LDIVH (RFJ unpublished data presented at the 2015 AHA/ASA International Stroke Conference symposium on neuroinflammation in aSAH and in abstract format at the 2015 AANS/CNS Joint Cerebrovascular Section Annual Meeting). It is important for academic physicians involved in the management of these complex patients to continue to explore new treatment options that may be protective against the potentially devastating "delayed brain injury" following cerebral aneurysm rupture. Several of the treatment options included in this review show promise and could be carefully adopted as the level of evidence for each improves. Other proposed neuroprotective treatments like statins and magnesium sulfate were previously thought to be very promising and to varying degrees were adopted at numerous institutions based on somewhat limited human evidence. Recent clinical trials and meta-analysis have shown no benefit for these treatments, and I currently no longer utilize either treatment as prophylaxis in my practice.

Advances in the understanding of delayed cerebral ischaemia after aneurysmal subarachnoid haemorrhage

Delayed cerebral ischaemia has been described as the single most important cause of morbidity and mortality in patients who survive the initial aneurysmal subarachnoid haemorrhage. Our understanding of the pathophysiology of delayed cerebral ischaemia is meagre at best and the calcium channel blocker nimodipine remains the only intervention to consistently improve functional outcome after aneurysmal subarachnoid haemorrhage. There is substantial evidence to support cerebral vessel narrowing as a causative factor in delayed cerebral ischaemia, but contemporary research demonstrating improvements in vessel narrowing has failed to show improved functional outcomes. This has encouraged researchers to investigate other potential causes of delayed cerebral ischaemia, such as early brain injury, microthrombosis, and cortical spreading depolarisation. Adherence to a common definition of delayed cerebral ischaemia is needed in order to allow easier assessment of studies using multiple different terms. Furthermore, improved recognition of delayed cerebral ischaemia would not only allow for faster treatment but also better assessment of interventions. Finally, understanding nimodipine's mechanism of action may allow us to develop similar agents with improved efficacy.

Cilostazol: an antiplatelet agent for the neurointerventionist?

Antiplatelet agents are essential for the successful management of patients undergoing a variety of neurointerventional procedures. The most commonly used anti-platelet agents are aspirin, clopidogrel and prasugrel. However, there exist an alternative class of anti-platelet agent that may prove useful for neurointerventionists. In particular a drug called cilostazol may have numerous added advantages above and beyond its antiplatelet effect that may be valuable for our patients. In this short review we aim to highlight some of these potential advantages.

The pathophysiology and treatment of delayed cerebral ischaemia following subarachnoid haemorrhage

Cerebral vasospasm has traditionally been regarded as an important cause of delayed cerebral ischaemia (DCI) which occurs after aneurysmal subarachnoid haemorrhage, and often leads to cerebral infarction and poor neurological outcome. However, data from recent studies argue against a pure focus on vasospasm as the cause of delayed ischaemic complications. Findings that marked reduction in the incidence of vasospasm does not translate to a reduction in DCI, or better outcomes has intensified research into other possible mechanisms which may promote ischaemic complications. Early brain injury and cell death, blood-brain barrier disruption and initiation of an inflammatory cascade, microvascular spasm, microthrombosis, cortical spreading depolarisations and failure of cerebral autoregulation, have all been implicated in the pathophysiology of DCI. This review summarises the current knowledge about the mechanisms underlying the development of DCI. Furthermore, it aims to describe and categorise the known pharmacological treatment options with respect to the presumed mechanism of action and its role in DCI.

Postoperative ICU management of patients after subarachnoid hemorrhage

PURPOSE OF REVIEW

This article reviews recent advances in the postoperative ICU management of patients after subarachnoid hemorrhage (SAH), especially with regards to hemodynamic management, methods of improving neurological outcomes, and management of cardiac and pulmonary complications.

RECENT FINDINGS

Several hemodynamic monitors and parameters may be useful for guiding volume therapy, including cardiac output, stroke volume variation monitoring, and global end-diastolic volume index. Early goal-directed hemodynamic therapy after SAH has recently been shown to improve clinical outcomes in patients with a poor clinical grade or coexisting cardiopulmonary complications. Recent laboratory and imaging modalities are being developed to identify patients at risk for developing vasospasm after SAH. Evidence for the use of various prophylactic adjuvant therapies to prevent vasospasm, including magnesium, phosphodiesterase 3 inhibitors, and therapeutic hypothermia, is emerging. Intrathecal administration of vasodilators or fibrinolytics may have offered advantages over systemic drug administration in the treatment of vasospasm. Pulmonary and cardiac complications are common after SAH, and are associated with an increased risk of mortality.

SUMMARY

The postoperative ICU period after SAH is associated with a significant morbidity and mortality risk, and recent studies have greatly contributed to our understanding of how to optimally manage these patients.

The role of arterioles and the microcirculation in the development of vasospasm after aneurysmal SAH

Cerebral vasospasm of the major cerebral arteries, which is characterized by angiographic narrowing of those vessels, had been recognized as a main contributor to delayed cerebral ischemia (DCI) in subarachnoid hemorrhage (SAH) patients. However, the CONSCIOUS-1 trial revealed that clazosentan could not improve mortality or clinical outcome in spite of successful reduction of relative risk in angiographic vasospasm. This result indicates that the pathophysiology underlying DCI is multifactorial and that other pathophysiological factors, which are independent of angiographic vasospasm, can contribute to the outcome. Recent studies have focused on microcirculatory disturbance, such as microthrombosis and arteriolar constriction, as a factor affecting cerebral ischemia after SAH. Reports detecting microthrombosis and arteriolar constriction will be reviewed, and the role of the microcirculation on cerebral ischemia during vasospasm after SAH will be discussed.