Efficacy of Cilostazol in Prevention of Delayed Cerebral Ischemia after Aneurysmal Subarachnoid Hemorrhage: A Meta-Analysis

CTP for the Screening of Vasospasm and Delayed Cerebral Ischemia in Aneurysmal SAH: A Systematic Review and Meta-analysis

BACKGROUND

Delayed cerebral ischemia and vasospasm are the most common causes of late morbidity following aneurysmal SAH, but their diagnosis remains challenging.

PURPOSE

This systematic review and meta-analysis investigated the diagnostic performance of CTP for detection of delayed cerebral ischemia and vasospasm in the setting of aneurysmal SAH.

DATA SOURCES

Studies evaluating the diagnostic performance of CTP in the setting of aneurysmal SAH were searched on the Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cochrane Clinical Answers, Cochrane Methodology Register, Ovid MEDLINE, EMBASE, American College of Physicians Journal Club, Database of Abstracts of Reviews of Effects, Health Technology Assessment, National Health Service Economic Evaluation Database, PubMed, and Google Scholar from their inception to September 2023.

STUDY SELECTION

Thirty studies were included, encompassing 1786 patients with aneurysmal SAH and 2302 CTP studies. Studies were included if they compared the diagnostic accuracy of CTP with a reference standard (clinical or radiologic delayed cerebral ischemia, angiographic spasm) for the detection of delayed cerebral ischemia or vasospasm in patients with aneurysmal SAH. The primary outcome was accuracy for the detection of delayed cerebral ischemia or vasospasm.

DATA ANALYSIS

Bivariate random effects models were used to pool outcomes for sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio. Subgroup analyses for individual CTP parameters and early-versus-late study timing were performed. Bias and applicability were assessed using the modified QUADAS-2 tool.

DATA SYNTHESIS

For assessment of delayed cerebral ischemia, CTP demonstrated a pooled sensitivity of 82.1% (95% CI, 74.5%-87.8%), specificity of 79.6% (95% CI, 73.0%-84.9%), positive likelihood ratio of 4.01 (95% CI, 2.94-5.47), and negative likelihood ratio of 0.23 (95% CI, 0.12-0.33). For assessment of vasospasm, CTP showed a pooled sensitivity of 85.6% (95% CI, 74.2%-92.5%), specificity of 87.9% (95% CI, 79.2%-93.3%), positive likelihood ratio of 7.10 (95% CI, 3.87-13.04), and negative likelihood ratio of 0.16 (95% CI, 0.09-0.31).

LIMITATIONS

QUADAS-2 assessment identified 12 articles with low risk, 11 with moderate risk, and 7 with a high risk of bias.

CONCLUSIONS

For delayed cerebral ischemia, CTP had a sensitivity of >80%, specificity of >75%, and a low negative likelihood ratio of 0.23. CTP had better performance for the detection of vasospasm, with sensitivity and specificity of >85% and a low negative likelihood ratio of 0.16. Although the accuracy offers the potential for CTP to be used in limited clinical contexts, standardization of CTP techniques and high-quality randomized trials evaluating its impact are required.

Beyond nimodipine: advanced neuroprotection strategies for aneurysmal subarachnoid hemorrhage vasospasm and delayed cerebral ischemia

The clinical management of aneurysmal subarachnoid hemorrhage (SAH)-associated vasospasm remains a challenge in neurosurgical practice, with its prevention and treatment having a major impact on neurological outcome. While considered a mainstay, nimodipine is burdened by some non-negligible limitations that make it still a suboptimal candidate of pharmacotherapy for SAH. This narrative review aims to provide an update on the pharmacodynamics, pharmacokinetics, overall evidence, and strength of recommendation of nimodipine alternative drugs for aneurysmal SAH-associated vasospasm and delayed cerebral ischemia. A PRISMA literature search was performed in the PubMed/Medline, Web of Science, ClinicalTrials.gov, and PubChem databases using a combination of the MeSH terms "medical therapy," "management," "cerebral vasospasm," "subarachnoid hemorrhage," and "delayed cerebral ischemia." Collected articles were reviewed for typology and relevance prior to final inclusion. A total of 346 articles were initially collected. The identification, screening, eligibility, and inclusion process resulted in the selection of 59 studies. Nicardipine and cilostazol, which have longer half-lives than nimodipine, had robust evidence of efficacy and safety. Eicosapentaenoic acid, dapsone and clazosentan showed a good balance between effectiveness and favorable pharmacokinetics. Combinations between different drug classes have been studied to a very limited extent. Nicardipine, cilostazol, Rho-kinase inhibitors, and clazosentan proved their better pharmacokinetic profiles compared with nimodipine without prejudice with effective and safe neuroprotective role. However, the number of trials conducted is significantly lower than for nimodipine. Aneurysmal SAH-associated vasospasm remains an area of ongoing preclinical and clinical research where the search for new drugs or associations is critical.

Pharmacological Prevention of Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Causes of morbidity and mortality following aneurysmal subarachnoid hemorrhage (aSAH) include early brain injury and delayed neurologic deterioration, which may result from delayed cerebral ischemia (DCI). Complex pathophysiological mechanisms underlie DCI, which often includes angiographic vasospasm (aVSP) of cerebral arteries.

METHODS

Despite the study of many pharmacological therapies for the prevention of DCI in aSAH, nimodipine-a dihydropyridine calcium channel blocker-remains the only drug recommended universally in this patient population. A common theme in the research of preventative therapies is the use of promising drugs that have been shown to reduce the occurrence of aVSP but ultimately did not improve functional outcomes in large, randomized studies. An example of this is the endothelin antagonist clazosentan, although this agent was recently approved in Japan.

RESULTS

The use of the only approved drug, nimodipine, is limited in practice by hypotension. The administration of nimodipine and its counterpart nicardipine by alternative routes, such as intrathecally or formulated as prolonged release implants, continues to be a rational area of study. Additional agents approved in other parts of the world include fasudil and tirilazad.

CONCLUSIONS

We provide a brief overview of agents currently being studied for prevention of aVSP and DCI after aSAH. Future studies may need to identify subpopulations of patients who can benefit from these drugs and perhaps redefine acceptable outcomes to demonstrate impact.

Antiplatelet therapy and outcomes after aneurysmal subarachnoid hemorrhage: A systematic review and meta-analysis

BACKGROUND

The efficacy of antiplatelet therapy (APT) after aneurysmal subarachnoid hemorrhage (aSAH) remains unclear. We performed a systematic review and meta-analysis to summarize the associations of APT use after aSAH with outcomes.

METHODS

We searched published medical literature to identify cohort studies involving adults with aSAH. The exposure was APT use after aSAH. Outcome measures were good functional outcome (modified Rankin Score 0-2 or Glasgow Outcome Scale 4-5), delayed cerebral ischemia (infarcts on neuroimaging), and intracranial hemorrhage. After assessing study heterogeneity and publication bias, we performed a meta-analysis using random-effects models to assess the strength of association between APT and SAH outcomes.

RESULTS

A total of 14 studies with 4228 aSAH patients were included. APT after aSAH was associated with good functional outcome (pooled relative risk, 1.08; 95% confidence interval, [CI], 1.02-1.15; I2 = 45%, p for heterogeneity = 0.04), but there was no relationship with delayed cerebral ischemia (pooled relative risk, 0.80; 95% confidence interval, [CI], 0.63-1.02; I2 = 61%, p for heterogeneity <0.01) or intracranial hemorrhage (pooled relative risk, 1.50; 95% confidence interval, [CI], 0.98-2.31; I2 = 0, p for heterogeneity =0.71). In additional analyses, APT resulted in good functional outcomes in endovascularly-treated patients. When stratified by type of medication, aspirin, clopidogrel, and ticlopidine were associated with good functional outcomes.

CONCLUSIONS

APT after aSAH was associated with a modest improvement in functional outcome, but there was no relationship with delayed cerebral ischemia or intracranial hemorrhage.

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.

A network meta-analysis of therapeutic and prophylactic management of vasospasm on aneurysmal subarachnoid hemorrhage outcomes

Background

Vasospasm and cerebral ischemia after aneurysmal subarachnoid hemorrhage are associated with mortality and poor neurological outcomes. We studied the efficacy of all available strategies targeting vasospasm and cerebral ischemia on outcomes in a network meta-analysis.

Methods

We searched EMBASE and MEDLINE databases from 1 January 1990 and 28 November 2021 according to PRISMA guidelines. Randomized controlled trials and longitudinal studies were included. All curative or preventive strategies targeting vasospasm and/or cerebral ischemia were eligible. A network meta-analysis was performed to compare all interventions with one another in a primary (randomized controlled trials only) and a secondary analysis (both trials and longitudinal studies). Mortality by 3 months was the primary outcome. Secondary outcomes were vasospasm, neurological outcome by 3 months, and dichotomized as "good" or "poor" recovery according to each study definition.

Results

A total of 2,382 studies were screened which resulted in the selection of 192 clinical trials (92 (47.9%) and 100 cohorts (52.1%) and the inclusion of 41,299 patients. In randomized controlled studies, no strategy decreased mortality by 3 months. Statins (0.79 [0.62-1]), tirilazad (0.82 [0.69-0.97]), CSF drainage (0.47 [0.29-0.77]), and clazosentan (0.51 [0.36-0.71]) significantly decreased the incidence of vasospasm. Cilostazol was the only treatment associated with improved neurological outcomes by 3 months in the primary (OR 1.16, 95% CI [1.05-1.28]) and secondary analyses (OR 2.97, 95% CI [1.39-6.32]).

Discussion

In the modern era of subarachnoid hemorrhage, all strategies targeting vasospasm failed to decrease mortality. Cilostazol should be confirmed as a treatment to improve neurological outcomes. The link between vasospasm and neurological outcome appears questionable.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=116073, identifier: PROSPERO CRD42018116073.

Therapies for Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) is one of the most important complications of subarachnoid hemorrhage. Despite lack of prospective evidence, medical rescue interventions for DCI include hemodynamic augmentation using vasopressors or inotropes, with limited guidance on specific blood pressure and hemodynamic parameters. For DCI refractory to medical interventions, endovascular rescue therapies (ERTs), including intraarterial (IA) vasodilators and percutaneous transluminal balloon angioplasty, are the cornerstone of management. Although there are no randomized controlled trials assessing the efficacy of ERTs for DCI and their impact on subarachnoid hemorrhage outcomes, survey studies suggest that they are widely used in clinical practice with significant variability worldwide. IA vasodilators are first line ERTs, with better safety profiles and access to distal vasculature. The most commonly used IA vasodilators include calcium channel blockers, with milrinone gaining popularity in more recent publications. Balloon angioplasty achieves better vasodilation compared with IA vasodilators but is associated with higher risk of life-threatening vascular complications and is reserved for proximal severe refractory vasospasm. The existing literature on DCI rescue therapies is limited by small sample sizes, significant variability in patient populations, lack of standardized methodology, variable definitions of DCI, poorly reported outcomes, lack of long-term functional, cognitive, and patient-centered outcomes, and lack of control groups. Therefore, our current ability to interpret clinical results and make reliable recommendations regarding the use of rescue therapies is limited. This review summarizes existing literature on rescue therapies for DCI, provides practical guidance, and identifies future research needs.

Effect of Cilostazol on Delayed Cerebral Infarction in Aneurysmal Subarachnoid Hemorrhage Using Explainable Predictive Modeling

The studies interpreting DCI, a complication of SAH, and identifying correlations are very limited. This study aimed to investigate the effect of cilostazol on ACV and DCI after coil embolization for ruptured aneurysms (n = 432). A multivariate analysis was performed and explainable artificial intelligence approaches were used to analyze the contribution of cilostazol as a risk factor on the development of ACV and DCI with respect to global and local interpretation. The cilonimo group was significantly lower than the nimo group in ACV (13.5% vs. 29.3; p = 0.003) and DCI (7.9% vs. 20.7%; p = 0.006), respectively. In a multivariate logistic regression, the odds ratio for DCI for the cilonimo group, female sex, and aneurysm size was 0.556 (95% confidence interval (CI), 0.351-0.879; p = 0.012), 3.713 (95% CI, 1.683-8.191; p = 0.001), and 1.106 (95% CI, 1.008-1.214; p = 0.034). The risk of a DCI occurrence was significantly increased with an aneurysm size greater than 10 mm (max 80%). The mean AUC of the XGBoost and logistic regression models was 0.94 ± 0.03 and 0.95 ± 0.04, respectively. Cilostazol treatment combined with nimodipine could decrease the prevalence of ACV (13.5%) and DCI (7.9%) in patients with aSAH.

Antiplatelet therapy and delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis

OBJECTIVE

Delayed cerebral ischemia (DCI) is a potentially preventable cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). The authors performed a meta-analysis to assess the effect of antiplatelet therapy (APT) on DCI in patients with aSAH.

METHODS

A systematic review of the PubMed and MEDLINE databases was performed. Study inclusion criteria were 1) ≥ 5 aSAH patients; 2) direct comparison between aSAH management with APT and without APT; and 3) reporting of DCI, angiographic, or symptomatic vasospasm rates for patients treated with versus without APT. The primary efficacy outcome was DCI. The outcomes of the APT versus no-APT cohorts were compared. Bias was assessed using the Downs and Black checklist.

RESULTS

The overall cohort comprised 2039 patients from 15 studies. DCI occurred less commonly in the APT compared with the no-APT cohort (pooled = 15.9% vs 28.6%; OR 0.47, p < 0.01). Angiographic (pooled = 51.6% vs 68.7%; OR 0.46, p < 0.01) and symptomatic (pooled = 23.6% vs 37.7%; OR 0.51, p = 0.01) vasospasm rates were lower in the APT cohort. In-hospital mortality (pooled = 1.7% vs 4.1%; OR 0.53, p = 0.01) and functional dependence (pooled = 21.0% vs 35.7%; OR 0.53, p < 0.01) rates were also lower in the APT cohort. Bleeding event rates were comparable between the two cohorts. Subgroup analysis of cilostazol monotherapy compared with no APT demonstrated a lower DCI rate in the cilostazol cohort (pooled = 10.6% vs 28.1%; OR 0.31, p < 0.01). Subgroup analysis of surgically treated aneurysms demonstrated a lower DCI rate for the APT cohort (pooled = 18.4% vs 33.9%; OR 0.43, p = 0.02).

CONCLUSIONS

APT is associated with improved outcomes in aSAH without an increased risk of bleeding events, particularly in patients who underwent surgical aneurysm repair and those treated with cilostazol. Although study heterogeneity is the most significant limitation of the analysis, the findings suggest that APT is worth exploring in patients with aSAH, particularly in a randomized controlled trial setting.

Updates on aneurysmal subarachnoid hemorrhage: is there anything really new?

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe disease, with systemic involvement and complex diagnosis and treatment. Since the current guidelines were published by the AHA/ASA, Neurocritical Care Society and the European Stroke Organization in 2012-2013,there has been an evolution in the comprehension of SAH-associated brain injury and its multiple underlying mechanisms. As a result, several clinical and translational trials were developed or are underway. Objective: The aim of this article is to review some updates in the diagnosis and treatment of neurological complications of SAH. Methods: A review of PubMed (May, 2010 to February, 2022) was performed. Data was summarized. Results: Content of five meta-analyses, nine review articles and 23 new clinical trials, including pilots, were summarized. Conclusions:Advances in the comprehension of pathophysiology and improvements in critical care have been reflected in the reduction of mortality in SAH. However, despite the number of publications, the only treatments shown to be effective in adequate, well-controlled clinical trials are nimodipine and repair of the ruptured aneurysm. Thus, doubts about the optimal management of SAH still persist.

Neutrophil Extracellular Traps and Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage

IMPORTANCE

Myeloperoxidase (MPO)-DNA complexes, biomarkers of neutrophil extracellular traps (NETs), have been associated with arterial and venous thrombosis. Their role in aneurysmal subarachnoid hemorrhage (aSAH) is unknown.

OBJECTIVES

To assess whether serum MPO-DNA complexes are present in patients with aSAH and whether they are associated with delayed cerebral ischemia (DCI).

DESIGN SETTING AND PARTICIPANTS

Post-hoc analysis of a prospective, observational single-center study, with de novo serum biomarker measurements in consecutive patients with aSAH between July 2018 and September 2020, admitted to a tertiary care neuroscience ICU.

MAIN OUTCOMES AND MEASURES

We analyzed serum obtained at admission and hospital day 4 for concentrations of MPO-DNA complexes. The primary outcome was DCI, defined as new infarction on brain CT. The secondary outcome was clinical vasospasm, a composite of clinical and transcranial Doppler parameters. We used Wilcoxon signed-rank-test to assess for differences between paired measures.

RESULTS

Among 100 patients with spontaneous subarachnoid hemorrhage, mean age 59 years (sd ± 13 yr), 55% women, 78 had confirmed aSAH. Among these, 29 (37%) developed DCI. MPO-DNA complexes were detected in all samples. The median MPO-DNA level was 33 ng/mL (interquartile range [IQR], 18-43 ng/mL) at admission, and 22 ng/mL (IQR, 11-31 ng/mL) on day 4 (unpaired test; p = 0.015). We found a significant reduction in MPO-DNA levels from admission to day 4 in patients with DCI (paired test; p = 0.036) but not in those without DCI (p = 0.17). There was a similar reduction in MPO-DNA levels between admission and day 4 in patients with (p = 0.006) but not in those without clinical vasospasm (p = 0.47).

CONCLUSIONS AND RELEVANCE

This is the first study to detect the NET biomarkers MPO-DNA complexes in peripheral serum of patients with aSAH and to associate them with DCI. A pronounced reduction in MPO-DNA levels might serve as an early marker of DCI. This diagnostic potential of MPO-DNA complexes and their role as potential therapeutic targets in aSAH should be explored further.

Comparison of Symptomatic Vasospasm after Surgical Clipping and Endovascular Coiling

Vasospasm, initial neurological damage, rebleeding, and periprocedural complications are associated prognostic factors for clinical outcomes after aneurysmal subarachnoid hemorrhage (SAH). In this study, factors related to delayed ischemic neurological deficit (DIND) are evaluated using data from our institute for the last 18 years. Data from 2001 to 2018 of patients with aneurysmal SAH who underwent surgical clipping (SC) or endovascular coiling (EC) within 7 days of onset were retrospectively analyzed. Cases of mortality within 5 days after treatment were excluded. Multivariate analysis was used to identify the risk factors for DIND. In total, 840 cases of SAH were assessed; among these cases, 384 (45.7%) and 456 (54.3%) were treated with SC and EC, respectively. The frequency of DIND in the EC group was significantly less than that in the SC group (11.8% vs. 17.7%; p = 0.016). In the results of multivariate analysis, internal carotid artery (ICA) aneurysm and hemorrhagic complications were the risk factors for DIND. Cilostazol administration and EC were significant factors for vasospasm prevention after aneurysmal SAH (odds ratio of ICA aneurysm: 1.59, hemorrhagic complications: 1.76, SC: 1.51, and cilostazol administration: 0.51, respectively). Cilostazol administration was also a significant factor in patients who were treated with EC. ICA aneurysm, treatment strategy, hemorrhagic complications, and cilostazol administration were associated with DIND. Oral administration of cilostazol and avoiding hemorrhagic complications were effective in DIND prevention. If both treatments are available for ruptured aneurysms, clinicians should choose EC on the basis of its ability to prevent DIND.

Prophylactic Therapies for Morbidity and Mortality After Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Network Meta-Analysis of Randomized Trials

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high mortality and morbidity. We aimed to determine the relative benefits of pharmacological prophylactic treatments in patients with aneurysmal subarachnoid hemorrhage by performing a network meta-analysis of randomized trials.

METHODS

We searched Medline, Web of Science, Embase, Scopus, ProQuest, and Cochrane Central to February 2020. Pairs of reviewers independently identified eligible trials, extracted data, and assessed the risk of bias. Eligible trials compared the prophylactic effects of any oral or intravenous medications or intracranial drug-eluting implants to one another or placebo or standard of care in adult hospitalized patients with confirmed aneurysmal subarachnoid hemorrhage. We used the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach to assess the certainty of the evidence.

RESULTS

We included 53 trials enrolling 10 415 patients. Nimodipine likely reduces all-cause mortality compared to placebo (odds ratio [OR],0.73 [95% CI, 0.53-1.00]; moderate certainty; absolute risk reduction (ARR), -3.35%). Nimodipine (OR, 1.46 [95% CI, 1.07-1.99]; high certainty; absolute risk increase, 8.25%) and cilostazol (OR, 3.73 [95% CI, 1.14-12.18]; moderate certainty; absolute risk increase, 23.15%) were the most effective treatments in improving disability at the longest follow-up. Compared to placebo, clazosentan (10 mg/kg; OR, 0.39 [95% CI, 0.22-0.68]; high certainty; ARR, -16.65%), nicardipine (OR, 0.48 [95% CI, 0.24-0.94]; moderate certainty; ARR, -13.70%), fasudil (OR, 0.55 [95% CI, 0.31-0.98]; moderate certainty; ARR, -11.54%), and magnesium (OR, 0.66 [95% CI, 0.46-0.94]; high certainty; ARR, -8.37%) proved most effective in reducing the likelihood of delayed cerebral ischemia.

CONCLUSIONS

Nimodipine and cilostazol are likely the most effective treatments in preventing morbidity and mortality in patients with aneurysmal subarachnoid hemorrhage. Clazosentan, nicardipine, fasudil, and magnesium showed beneficial effects on delayed cerebral ischemia and vasospasm but they were not found to reduce mortality or disability. Future trials are warranted to elaborately investigate the prophylactic effects of medications that may improve mortality and long-term functional outcomes, such as cilostazol and clazosentan.

REGISTRATION

URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42019122183.

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.

Therapeutic Approaches for Cerebrovascular Dysfunction After Aneurysmal Subarachnoid Hemorrhage: An Update and Future Perspectives

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe subtype of stroke occurring at a relatively young age with a significant socioeconomic impact. Treatment of aSAH includes early aneurysm exclusion, intensive care management, and prevention of complications. Once the aneurysm rupture occurs, blood spreading within the subarachnoid space triggers several molecular pathways causing early brain injury and delayed cerebral ischemia. Pathophysiologic mechanisms underlying brain injury after aSAH are not entirely characterized, reflecting the difficulties in identifying effective therapeutic targets for patients with aSAH. Although the improvements of the last decades in perioperative management, early diagnosis, aneurysm exclusion techniques, and medical treatments have increased survival, vasospasm and delayed cerebral infarction are associated with high mortality and morbidity. Clinical practice can rely on a few specific therapeutic agents, such as nimodipine, a calcium-channel blocker proved to reduce severe neurologic deficits in these patients. Therefore, new pharmacologic approaches are needed to improve the outcome of this life-threatening condition, as well as a tailored rehabilitation plan to maintain the quality of life in aSAH survivors. Several clinical trials are investigating the efficacy and safety of emerging drugs, such as magnesium, clazosentan, cilostazol, interleukin 1 receptor antagonists, deferoxamine, erythropoietin, and nicardipine, and continuous lumbar drainage in the setting of aSAH. This narrative review focuses on the most promising therapeutic interventions after aSAH.

Antiplatelet therapy for standalone coiling of ruptured intracranial aneurysms: a systematic review and meta-analysis

BACKGROUND

Endovascular embolization using standalone coils is the preferred treatment option for ruptured cerebral aneurysms to avoid the use of dual antiplatelet therapy with stent coiling or endoluminal flow diversion devices. However, it has been reported that patients undergoing the standalone coiling approach are at risk for periprocedural thromboembolism. Therefore, this systematic review and meta-analysis was performed to clarify the risks and benefits of antiplatelet therapy (AT) during coiling procedures performed to treat ruptured aneurysms, including the incidence of early thromboembolic events, hemorrhagic and delayed ischemic events, as well as clinical outcomes.

METHODS

A comprehensive search of three databases was performed for articles from inception to June 2021. After fulfilling the inclusion criteria, five studies were included in this meta-analysis and 462 patients with aneurysmal subarachnoid hemorrhage (aSAH) were identified who underwent endovascular standalone coiling treatment. Aneurysm location, patient characteristics, and aSAH grades were comparable between the AT and non-AT groups.

RESULTS

AT significantly decreased the incidence of thromboembolic events immediately after the coiling procedures compared with non-AT (OR 3.42; 95% CI 1.77 to 6.61, p<0.001). The incidences of hemorrhage, delayed ischemia, and clinical outcomes with or without AT were not significantly different between groups.

CONCLUSIONS

Although this study showed no beneficial effect of AT on clinical outcomes, the results suggest that AT could be combined with standalone coiling to avoid thromboembolism during the perioperative period. A large prospective study and/or an additional meta-analysis would be required to further investigate how AT benefits standalone coil embolization in aSAH.

Role of microcirculatory impairment in delayed cerebral ischemia and outcome after aneurysmal subarachnoid hemorrhage

Early brain injury (EBI) is considered an important cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). As a factor in EBI, microcirculatory dysfunction has become a focus of interest, but whether microcirculatory dysfunction is more important than angiographic vasospasm (aVS) remains unclear. Using data from 128 cases, we measured the time to peak (TTP) in several regions of interest on digital subtraction angiography. The intracerebral circulation time (iCCT) was obtained between the TTP in the ultra-early phase (the baseline iCCT) and in the subacute phase and/or at delayed cerebral ischemia (DCI) onset (the follow-up iCCT). In addition, the difference in the iCCT was calculated by subtracting the baseline iCCT from the follow-up iCCT. Univariate analysis showed that DCI was significantly increased in those patients with a prolonged baseline iCCT, prolonged follow-up iCCT, increased differences in the iCCT, and with severe aVS. Poor outcome was significantly increased in patients with prolonged follow-up iCCT and increased differences in the iCCT. Multivariate analysis revealed that increased differences in the iCCT were a significant risk factor that increased DCI and poor outcome. The results suggest that the increasing microcirculatory dysfunction over time, not aVS, causes DCI and poor outcome after aneurysmal aSAH.

Update on Cilostazol: A Critical Review of Its Antithrombotic and Cardiovascular Actions and Its Clinical Applications

Cilostazol, a phosphodiesterase III inhibitor, has vasodilating and antiplatelet properties with a low rate of bleeding complications. It has been used over the past 25 years for improving intermittent claudication in patients with peripheral artery disease (PAD). Cilostazol also has demonstrated efficacy in patients undergoing percutaneous revascularization procedures for both PAD and coronary artery disease. In addition to its antithrombotic and vasodilating actions, cilostazol also inhibits vascular smooth muscle cell proliferation via phosphodiesterase III inhibition, thus mitigating restenosis. Accumulated evidence has shown that cilostazol, due to its "pleiotropic" effects, is a useful, albeit underutilized, agent for both coronary artery disease and PAD. It is also potentially useful after ischemic stroke and is an alternative in those who are allergic or intolerant to classical antithrombotic agents (eg, aspirin or clopidogrel). These issues are herein reviewed together with the pharmacology and pharmacodynamics of cilostazol. Large studies and meta-analyses are presented and evaluated. Current guidelines are also discussed, and the spectrum of cilostazol's actions and therapeutic applications are illustrated.

Intensive therapies of delayed cerebral ischemia after subarachnoid hemorrhage: a propensity-matched comparison of different center-driven strategies

BACKGROUND

Intensive therapies of delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage (aSAH) have still controversial and unproven benefit. We aimed to compare the overall efficacy of two different center-driven strategies for the treatment of DCI respectively with and without vasospasm angioplasty.

METHODS

Two hundred consecutive patients with aSAH were enrolled in each of two northern European centers. In an interventional center, vasospasm angioplasty was indicated as first line rather than rescue treatment of DCI using distal percutaneous balloon angioplasty technique combined with intravenous milrinone. In non-interventional center, induced hypertension was the only intensive therapy of DCI. Radiological DCI (new cerebral infarcts not visible on immediate post-treatment imaging), death at 1 month, and favorable outcome at 6 months (modified Rankin scale score ≤ 2) were retrospectively analyzed by independent observers and compared between two centers before and after propensity score (PS) matching for baseline characteristics.

RESULTS

Baseline characteristics only differed between centers for age and rate of smokers and patients with chronic high blood pressure. In the interventional center, vasospasm angioplasty was performed in 38% of patients with median time from bleeding of 8 days (Q1 = 6.5;Q3 = 10). There was no significant difference of incidence of radiological DCI (9% vs.14%, P = 0.11), death (8% vs. 9%, P = 0.4), and favorable outcome 74% vs. 72% (P = 0.4) between interventional and non-interventional centers before and after PS matching.

CONCLUSIONS

Our results suggest either that there is no benefit, or might be minimal, of one between two different center-driven strategies for intensive treatment of DCI. Despite potential lack of power or unknown confounders in our study, these results question the use of such intensive therapies in daily practice without further optimization and validation.

Delayed Cerebral Ischemia after Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) is the most feared complication of aneurysmal subarachnoid hemorrhage (aSAH). It increases the mortality and morbidity associated with aSAH. Previously, large cerebral artery vasospasm was thought to be the sole major contributing factor associated with increased risk of DCI. Recent literature has challenged this concept. We conducted a literature search using PUBMED as the prime source of articles discussing various other factors which may contribute to the development of DCI both in the presence or absence of large cerebral artery vasospasm. These factors include microvascular spasm, micro-thrombosis, cerebrovascular dysregulation, and cortical spreading depolarization. These factors collectively result in inflammation of brain parenchyma, which is thought to precipitate early brain injury and DCI. We conclude that diagnostic modalities need to be refined in order to diagnose DCI more efficiently in its early phase, and newer interventions need to be developed to prevent and treat this condition. These newer interventions are currently being studied in experimental models. However, their effectiveness on patients with aSAH is yet to be determined.

Pathophysiology of Delayed Cerebral Ischemia After Subarachnoid Hemorrhage: A Review

Delayed cerebral ischemia is a major predictor of poor outcomes in patients who suffer subarachnoid hemorrhage. Treatment options are limited and often ineffective despite many years of investigation and clinical trials. Modern advances in basic science have produced a much more complex, multifactorial framework in which delayed cerebral ischemia is better understood and novel treatments can be developed. Leveraging this knowledge to improve outcomes, however, depends on a holistic understanding of the disease process. We conducted a review of the literature to analyze the current state of investigation into delayed cerebral ischemia with emphasis on the major themes that have emerged over the past decades. Specifically, we discuss microcirculatory dysfunction, glymphatic impairment, inflammation, and neuroelectric disruption as pathological factors in addition to the canonical focus on cerebral vasospasm. This review intends to give clinicians and researchers a summary of the foundations of delayed cerebral ischemia pathophysiology while also underscoring the interactions and interdependencies between pathological factors. Through this overview, we also highlight the advances in translational studies and potential future therapeutic opportunities.

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.

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.

Efficacy and safety of cilostazol-nimodipine combined therapy on delayed cerebral ischaemia after aneurysmal subarachnoid haemorrhage: a prospective, randomised, double-blinded, placebo-controlled trial protocol

INTRODUCTION

Delayed cerebral ischaemia (DCI) due to cerebral vasospasm (cVS) remains the foremost contributor to morbidity and mortality following aneurysmal subarachnoid haemorrhage (aSAH). Past efforts in preventing and treating DCI have failed to make any significant progress. To date, our most effective treatment involves the use of nimodipine, a calcium channel blocker. Recent studies have suggested that cilostazol, a platelet aggregation inhibitor, may prevent cVS. Thus far, no study has evaluated the effect of cilostazol plus nimodipine on the rate of DCI following aSAH.

METHODS AND ANALYSIS

This is a multicentre, double-blinded, randomised, placebo-controlled superiority trial investigating the effect of cilostazol on DCI. Data concerning rates of DCI, symptomatic and radiographic vasospasm, length of intensive care unit stay, and long-term functional and quality-of-life (QoL) outcomes will be recorded. All data will be collected with the aim of demonstrating that the use of cilostazol plus nimodipine will safely decrease the incidence of DCI, and decrease the rates of both radiographic and symptomatic vasospasm with subsequent improvement in long-term functional and QoL outcomes when compared with nimodipine alone.

ETHICS AND DISSEMINATION

Ethical approval was obtained from all participating hospitals by the Ascension Providence Hospital Institutional Review Board. The results of this study will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04148105.

Microvascular platelet aggregation and thrombosis after subarachnoid hemorrhage: A review and synthesis

Delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (SAH) has been associated with numerous pathophysiological sequelae, including large artery vasospasm and microvascular thrombosis. The focus of this review is to provide an overview of experimental animal model studies and human autopsy studies that explore the temporal-spatial characterization and mechanism of microvascular platelet aggregation and thrombosis following SAH, as well as to critically assess experimental studies and clinical trials highlighting preventative therapeutic options against this highly morbid pathophysiological process. Upon review of the literature, we discovered that microvascular platelet aggregation and thrombosis occur after experimental SAH across multiple species and SAH induction techniques in a similar time frame to other components of DCI, occurring in the cerebral cortex and hippocampus across both hemispheres. We discuss the relationship of these findings to human autopsy studies. In the final section of this review, we highlight the important therapeutic options for targeting microvascular platelet aggregation and thrombosis, and emphasize why therapeutic targeting of this neurovascular pathology may improve patient care. We encourage ongoing research into the pathophysiology of SAH and DCI, especially in regard to microvascular platelet aggregation and thrombosis and the translation to randomized clinical trials.

The effect of pentoxifylline on cerebral vasospasm following experimental subarachnoid hemorrhage

OBJECTS

Cerebral vasospasm is an important event that occurs following subarachnoid hemorage which has significant mortality and morbidity. The goal in this study was to investigate the effect of pentoxifylline on vasospasm in an experimental subarachnoid hemorrhage model.

METHODS

In this study, 20 male New Zeland White rabbits weighing 3000-3500 g were assigned randomly to four groups. Animals in group 1 served as controls. Animals in group two received only intravenous pentoxifylline injection 3 times in 12 h intervals. In group 3, SAH was induced and no injection was given. Animals in group 4 received intravenous pentoxifylline (6 mg/kg) injections 3 times at 12^th, 24^th and 36^th hours after subarachnoid hemorrhage induction. All animals were sacrificed and basilar arteries were removed at 48th hour. Basilar artery vessel diameters, wall thicknesses and luminal section areas were measured with Spot for Windows version 4.1. Statistical analysis was performed using ANOVA and Kruskall-Wallis tests.

RESULTS

Mean basilar artery luminal section areas and luminal diameters in group 4 were significantly higher compared to group 3 (p < 0.05). Basilar artery wall thicknesses and were found to be higher in group 3 than in other groups and this was also statistically significant (p < 0.05).

CONCLUSION

Our study demonstrated that intravenous administration of pentoxifylline significantly decreases vasospasm after subarachnoid hemorrhage.

Progress in the Mechanism and Clinical Application of Cilostazol

Cilostazol is a unique platelet inhibitor that has been used clinically for more than 20 years. As a phosphodiesterase type III inhibitor, cilostazol is capable of reversible inhibition of platelet aggregation and vasodilation, has antiproliferative effects, and is widely used in the treatment of peripheral arterial disease, cerebrovascular disease, percutaneous coronary intervention, etc. This article briefly reviews the pharmacological mechanisms and clinical application of cilostazol.

Clinical and experimental aspects of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) continues to be associated with significant morbidity and mortality despite advances in care and aneurysm treatment strategies. Cerebral vasospasm continues to be a major source of clinical worsening in patients. We intended to review the clinical and experimental aspects of aSAH and identify strategies that are being evaluated for the treatment of vasospasm. A literature review on aSAH and cerebral vasospasm was performed. Available treatments for aSAH continue to expand as research continues to identify new therapeutic targets. Oral nimodipine is the primary medication used in practice given its neuroprotective properties. Transluminal balloon angioplasty is widely utilized in patients with symptomatic vasospasm and ischemia. Prophylactic "triple-H" therapy, clazosentan, and intraarterial papaverine have fallen out of practice. Trials have not shown strong evidence supporting magnesium or statins. Other calcium channel blockers, milrinone, tirilazad, fasudil, cilostazol, albumin, eicosapentaenoic acid, erythropoietin, corticosteroids, minocycline, deferoxamine, intrathecal thrombolytics, need to be further investigated. Many of the current experimental drugs may have significant roles in the treatment algorithm, and further clinical trials are needed. There is growing evidence supporting that early brain injury in aSAH may lead to significant morbidity and mortality, and this needs to be explored further.

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.