Aspirin and delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

Prevention of Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage-Summary of Existing Clinical Evidence

The 2023 International Subarachnoid Hemorrhage Conference identified a need to provide an up-to-date review on prevention methods for delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage and highlight areas for future research. A PubMed search was conducted for key factors contributing to development of delayed cerebral ischemia: anesthetics, antithrombotics, cerebrospinal fluid (CSF) diversion, hemodynamic, endovascular, and medical management. It was found that there is still a need for prospective studies analyzing the best methods for anesthetics and antithrombotics, though inhaled anesthetics and antiplatelets were found to have some advantages. Lumbar drains should increasingly be considered the first line of CSF diversion when applicable. Finally, maintaining euvolemia before and during vasospasm is recommended as there is no evidence supporting prophylactic spasmolysis or angioplasty. There is accumulating observational evidence, however, that intra-arterial spasmolysis with refractory DCI might be beneficial in patients not responding to induced hypertension. Nimodipine remains the medical therapy with the most support for prevention.

Racial and ethnic differences in restarting antiplatelet therapy in patients with primary intracranial hemorrhage: a systematic review and meta-analysis

BACKGROUND

There has long been clinical disagreement over the resumption of antiplatelet therapy in patients with primary intracranial hemorrhage (ICH). This meta-analysis aimed to systematically evaluate the efficacy and safety of restarting antiplatelet therapy after ICH among different races and ethnicities.

METHODS

All relevant medical studies involving adults with antiplatelet-associated ICH published in PubMed, The Cochrane Library and Chinese National Knowledge Infrastructure from inception to March 2024 were sourced. Outcome measures were thromboembolic events (stroke and myocardial infarction) and recurrence of ICH. After assessing study heterogeneity and publication bias, we performed a meta-analysis using random-effects model to assess the strength of association between resumption of antiplatelet therapy and our outcomes.The review was not registered and the review protocol was not prepared.

RESULTS

Thirty-five studies were included, with 9758 ICH patients. Subgroup analysis revealed that restarting antiplatelet therapy was associated with a significantly higher risk of recurrence or aggravation of cerebral hemorrhage in Asians[OR = 1.48, 95% CI (1.13-1.94), P = 0.004]; in Caucasians, on the contrary, reinitiation of antiplatelet therapy was not associated with a significantly higher risk of recurrence or aggravation of cerebral hemorrhage [OR = 0.85, 95% CI (0.67-1.06), P = 0.149]. Reinitiation of antiplatelet therapy was associated with a significantly lower risk of cerebral infarction [OR = 0.61, 95% CI (0.39-0.96), P = 0.033]. Restarting antiplatelet therapy after cerebral hemorrhage was not associated with a higher incidence rate of mortality [OR = 0.79, 95% CI (0.57, 1.08), P = 0.138], myocardial infarction [OR = 2.40, 95%CI (0.53,10.79), P = 0.253], hemiparesis [OR = 0.38, 95%CI (0.03,4.81), P = 0.451], neurological deficit [OR = 0.86,95%CI(0.32,2.33),P = 0.766].

CONCLUSION

Reinstitution of antiplatelet therapy after ICH was associated with a lower risk of thromboembolic complications.Resumption of antiplatelet therapy was not associated with a higher incidence of cerebral hemorrhage in Caucasians, but may be associated with a higher risk of cerebral hemorrhage recurrence in Asian populations.

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.

Antiplatelet therapy in aneurysmal subarachnoid hemorrhage: an updated meta-analysis

Antiplatelet therapy (AT) may serve to reduce the effects of aneurysmal subarachnoid hemorrhage (aSAH)-induced pro-coagulant state in the cerebral circulation. Several studies, however, have delivered conflicting conclusions on the efficacy of AT post aSAH. Systematic searches of Medline, Embase, and Cochrane Central were undertaken on 27th March 2023. The primary outcome was delayed cerebral ischaemia (DCI). Secondary outcomes were symptomatic and angiographic vasospasm, good functional outcome (modified Rankin Scale [mRS] with scores 0-2), hemorrhagic events, and in-hospital mortality. Twenty-two studies reporting 4378 patients with aSAH were included in the meta-analysis. AT was associated with lower rates of DCI (RR=0.62, 95% CI: 0.43; 0.89), symptomatic vasospasm (RR=0.63, 95% CI: 0.46; 0.86), and moderate/severe angiographic vasospasm (RR=0.74, 95% CI: 0.65; 0.84), with no effect on hemorrhagic complications (RR=1.36, 95% CI: 0.77; 2.41). When analyzing only post-ictal use of AT, AT additionally favored rates of good functional outcomes (RR=1.18, 95% CI: 1.10; 1.26) and in-hospital mortality (RR=0.56, 95% CI: 0.39; 0.80). In the subgroup treated with cilostazol, AT was associated with lower rates of DCI (RR=0.40, 95% CI: 0.32), symptomatic vasospasm (RR=0.47, 95% CI: 0.33; 0.65), moderate/severe angiographic vasospasm (RR=0.75, 95% CI: 0.57; 0.98) and good functional outcome (RR=1.24, 95% CI: 1.08; 1.43). In the surgically treated aSAH subgroup, AT favored rates of symptomatic vasospasm (RR=0.55, 95% CI: 0.30; 0.98), moderate/severe angiographic vasospasm (RR=0.70, 95% CI: 0.54; 0.90) and good functional outcome (RR=1.23, 95% CI: 1.09; 1.41). In the endovascularly treated aSAH subgroup, AT was associated with lower rates of in-hospital mortality (RR=0.60, 95% CI: 0.41; 0.88). In aSAH patients, post-ictal AT is associated with benefits in terms of rates of DCI, vasospasm, good functional outcomes, and in-hospital mortality without an increased risk of hemorrhagic events.

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.

Hemostasis and Fibrinolysis following Aneurysmal Subarachnoid Hemorrhage: A Systematic Review on Additional Knowledge from Dynamic Assays and Potential Treatment Targets

Mortality after aneurysmal subarachnoid hemorrhage (aSAH) is augmented by rebleeding and delayed cerebral ischemia (DCI). A range of assays evaluating the dynamic process of blood coagulation, from activation of clotting factors to fibrinolysis, has emerged and a comprehensive review of hemostasis and fibrinolysis following aSAH may reveal targets of treatment. We conducted a systematic review of existing literature assessing coagulation and fibrinolysis following aSAH, but prior to treatment. PubMed, Embase, and Web of Science were searched on November 18, 2020, without time boundaries. In total, 45 original studies were eventually incorporated into this systematic review, divided into studies presenting data only from conventional or quantitative assays (n = 22) and studies employing dynamic assays (n = 23). Data from conventional or quantitative assays indicated increased platelet activation, whereas dynamic assays detected platelet dysfunction possibly related to an increased risk of rebleeding. Secondary hemostasis was activated in conventional, quantitative, and dynamic assays and this was related to poor neurological outcome and mortality. Studies systematically investigating fibrinolysis were sparse. Measurements from conventional or quantitative assays, as well as dynamic fibrinolysis assays, revealed conflicting results with normal or increased lysis and changes were not associated with outcome. In conclusion, dynamic assays were able to detect reduced platelet function, not revealed by conventional or quantitative assays. Activation of secondary hemostasis was found in both dynamic and nondynamic assays, while changes in fibrinolysis were not convincingly demonstrable in either dynamic or conventional or quantitative assays. Hence, from a mechanistic point of view, desmopressin to prevent rebleeding and heparin to prevent DCI may hold potential as therapeutic options. As changes in fibrinolysis were not convincingly demonstrated and not related to outcome, the use of tranexamic acid prior to aneurysm closure is not supported by this review.

An overview of pharmacotherapy for cerebral vasospasm and delayed cerebral ischemia after subarachnoid hemorrhage

Introduction: Survival from aneurysmal subarachnoid hemorrhage has increased in the past few decades. However, functional outcome after subarachnoid hemorrhage is still suboptimal. Delayed cerebral ischemia (DCI) is one of the major causes of morbidity.Areas covered: Mechanisms underlying vasospasm and DCI after aneurysmal subarachnoid hemorrhage and pharmacological treatment are summarized in this review.Expert opinion: Oral nimodine, an L-type dihydropyridine calcium channel blocker, is the only FDA-approved drug for the prevention and treatment of neurological deficits after aneurysmal subarachnoid hemorrhage. Fasudil, a potent Rho-kinase inhibitor, has also been shown to improve the clinical outcome and has been approved in some countries for use in patients with aneurysmal subarachnoid hemorrhage. Although other drugs, including nicardipine, cilostazol, statins, clazosentan, magnesium and heparin, have been expected to have beneficial effects on DCI, there has been no convincing evidence supporting the routine use of those drugs in patients with aneurysmal subarachnoid hemorrhage in clinical practice. Further elucidation of the mechanisms underlying DCI and the development of effective therapeutic strategies for DCI, including combination therapy, are necessary to further improve the functional outcome and mortality after subarachnoid hemorrhage.

Effects of post-interventional antiplatelet therapy on angiographic vasospasm, delayed cerebral ischemia, and clinical outcome after aneurysmal subarachnoid hemorrhage: a single-center experience

Platelet activation has been postulated to be involved in the pathogenesis of delayed cerebral ischemia (DCI) and cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage (aSAH). The aim of this study was to investigate potentially beneficial effects of antiplatelet therapy (APT) on angiographic CVS, DCI-related infarction and functional outcome in endovascularly treated aSAH patients. Retrospective single-center analysis of aSAH patients treated by endovascular aneurysm obliteration. Based on the post-interventional medical regime, patients were assigned to either an APT group or a control group not receiving APT. A subgroup analysis separately investigated those APT patients with aspirin monotherapy (MAPT) and those receiving dual treatment (aspirin plus clopidogrel, DAPT). Clinical and radiological characteristics were compared between groups. Possible predictors for angiographic CVS, DCI-related infarction, and an unfavorable functional outcome (modified Rankin scale ≥ 3) were analyzed. Of 160 patients, 85 (53%) had received APT (n = 29 MAPT, n = 56 DAPT). APT was independently associated with a lower incidence of an unfavorable functional outcome (OR 0.40 [0.19-0.87], P = 0.021) after 3 months. APT did not reduce the incidence of angiographic CVS or DCI-related infarction. The pattern of angiographic CVS or DCI-related infarction as well as the rate of intracranial hemorrhage did not differ between groups. However, the lesion volume of DCI-related infarctions was significantly reduced in the DAPT subgroup (P = 0.011). Post-interventional APT in endovascularly treated aSAH patients is associated with better functional outcome at 3 months. The beneficial effect of APT might be mediated by reduction of the size of DCI-related infarctions.

Post-treatment Antiplatelet Therapy Reduces Risk for Delayed Cerebral Ischemia due to Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Delayed cerebral ischemia (DCI) has a strong impact on outcome of patients with aneurysmal subarachnoid hemorrhage (SAH). Positive effect of antiplatelet therapy on DCI rates has been supposed upon smaller SAH series.

OBJECTIVE

To analyze the benefit/risk profile of antiplatelet use in SAH patients.

METHODS

This retrospective case-control study was based on institutional observational cohort with 994 SAH patients treated between January 2003 and June 2016. The individuals with postcoiling antiplatelet therapy (aspirin with/without clopidogrel) were compared to a control group without antiplatelet therapy. Occurrence of DCI, major/minor bleeding events in the follow-up computed tomography scans, and favorable outcome at 6 mo after SAH (modified Rankin scale < 3) were compared in both groups.

RESULTS

Of 580 patients in the final analysis, 329 patients received post-treatment antiplatelet medication. There were no significant differences between the compared groups with regard to basic outcome confounders. Aspirin use was independently associated with reduced DCI risk (P < .001, adjusted odds ratio = 0.41, 95% confidence interval 0.24-0.65) and favorable outcome (P = .02, adjusted odds ratio = 1.78, 95% confidence interval 1.06-2.98). Regarding bleeding complications, aspirin was associated only with minor bleeding events (P = .02 vs P = .51 for major bleeding events).

CONCLUSION

Regular administration of aspirin might have a positive impact on DCI risk and outcome of SAH patients, without increasing the risk for clinically relevant bleeding events. In our SAH cohort, dual antiplatelet therapy showed no additional benefit on DCI risk, but increased the likelihood of major bleeding events.

Impact of Postoperative Infarcts in Determining Outcome after Clipping of Anterior Communicating Artery Aneurysms

Background

Development of cerebral infarcts following clipping of ruptured intracranial aneurysm is one of the major determinants of functional outcome in patients with subarachnoid hemorrhage (SAH). The aim of this study is to evaluate the factors affecting development of postoperative infarcts, its incidence, pattern, and functional outcome.

Material and Methods

This study includes 118 patients of spontaneous SAH because of ruptured anterior communicating artery aneurysm, who underwent clipping. Relevant points in history, preoperative and intraoperative findings, and postoperative outcome are evaluated.

Results

29 of 118 (24.5%) patients developed postoperative radiological infarcts. Approximately 37.9%, 17.2%, and 3.4% patients developed isolated infarcts, respectively, in anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA) territory. About 20.7% patients developed infarcts in deep perforator territory. Nine of 29 (31.3%) patients developed multiple-vessel territory infarcts. Patients with poor preoperative neurologic status, prior history of seizure, and history of intraoperative rupture had higher chances of development of infarcts. Development of infarct was irrespective of temporary clipping (TC), duration of clipping, and elective versus rescue clipping. Development of infarcts adversely affected the outcome in significant proportions. Among patients with infarcts, unilateral ACA territory infarcts showed best prognosis, whereas all patients with multiple territory infarcts and PCA territory infarcts died. Age or sex of the patients did not affect the functional outcome. Timing of development of infarcts has no influence on functional recovery.

Conclusion

Development of symptomatic infarct is the sole important predictor of functional outcome. A crowded neurovascular neighborhood and complex variations in local angioarchitecture make anterior communication (ACOM) territory predisposed to operative insults. Elective TC and aggressive management of cerebral vasospasm are recommended to prevent development of infarcts.

Characteristics of Unruptured Compared to Ruptured Intracranial Aneurysms: A Multicenter Case-Control Study

BACKGROUND

Only a minority of intracranial aneurysms rupture to cause subarachnoid hemorrhage.

OBJECTIVE

To test the hypothesis that unruptured aneurysms have different characteristics and risk factor profiles compared to ruptured aneurysms.

METHODS

We recruited patients with unruptured aneurysms or aneurysmal subarachnoid hemorrhages at 22 UK hospitals between 2011 and 2014. Demographic, clinical, and imaging data were collected using standardized case report forms. We compared risk factors using multivariable logistic regression.

RESULTS

A total of 2334 patients (1729 with aneurysmal subarachnoid hemorrhage, 605 with unruptured aneurysms) were included (mean age 54.22 yr). In multivariable analyses, the following variables were independently associated with rupture status: black ethnicity (odds ratio [OR] 2.42; 95% confidence interval [CI] 1.29-4.56, compared to white) and aneurysm location (anterior cerebral artery/anterior communicating artery [OR 3.21; 95% CI 2.34-4.40], posterior communicating artery [OR 3.92; 95% CI 2.67-5.74], or posterior circulation [OR 3.12; 95% CI 2.08-4.70], compared to middle cerebral artery). The following variables were inversely associated with rupture status: antihypertensive medication (OR 0.65; 95% CI 0.49-0.84), hypercholesterolemia (0.64 OR; 95% CI 0.48-0.85), aspirin use (OR 0.28; 95% CI 0.20-0.40), internal carotid artery location (OR 0.53; 95% CI 0.38-0.75), and aneurysm size (per mm increase; OR 0.76; 95% CI 0.69-0.84).

CONCLUSION

We show substantial differences in patient and aneurysm characteristics between ruptured and unruptured aneurysms. These findings support the hypothesis that different pathological mechanisms are involved in the formation of ruptured aneurysms and incidentally detected unruptured aneurysms. The potential protective effect of aspirin might justify randomized prevention trials in patients with unruptured aneurysms.

Antiplatelet Therapy in Patients with Aneurysmal SAH: Impact on Delayed Cerebral Ischemia and Clinical Outcome. A Meta-Analysis

BACKGROUND AND PURPOSE

Delayed cerebral ischemia strongly impacts clinical outcome after aneurysmal SAH. The effect of antiplatelet therapy on delayed cerebral ischemia has been described with heterogeneous results. Our aim was to analyze the efficacy of antiplatelet therapy on delayed cerebral ischemia and clinical outcome in patients with SAH.

DATA SOURCES

A systematic search of 3 databases was performed for studies published from 1990 to 2019.

STUDY SELECTION

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies comparing the rates of delayed cerebral ischemia and clinical outcomes among patients with SAH with and without antiplatelet therapy.

DATA ANALYSIS

Random-effects meta-analysis was used to pool the following: delayed cerebral ischemia, mortality, and good outcome rates.

DATA SYNTHESIS

Including 7 studies, 1060 and 1762 patients with SAH were endovascularly or surgically treated with (cases) and without (controls) antiplatelet therapy, respectively. Overall, antiplatelet therapy did not significantly decrease delayed cerebral ischemia rates compared with the control group (219/1060 versus 485/1762, OR = 0.781; 95% CI, 0.46-1.31; P = .33). Among patients treated endovascularly, there was a trend toward lower delayed cerebral ischemia rates after antiplatelet therapy (157/778 versus 413/1410, OR = 0.552; 95% CI, 0.273-1.115; P = .06). Long-term (>2 weeks) antiplatelet therapy tended to be associated with a lower incidence of delayed cerebral ischemia (63/438 versus 96/353, OR = 0.379; 95% CI, 0.12-1.2; P = .06). The good-outcome rate was significantly higher (803/1144 versus 1175/1775, OR = 1.368; 95% CI, 1.117-1.676; P = .002) and the mortality rate was significantly lower (79/672 versus 97/571, OR = 0.656; 95% CI, 0.47-0.91; P = .01) among the antiplatelet therapy group.

LIMITATIONS

Heterogeneity was high for most outcomes.

CONCLUSIONS

Overall, the incidence of delayed cerebral ischemia seems not to be significantly reduced among the antiplatelet therapy group. However, delayed cerebral ischemia tended to be lower among subjects with both long-term antiplatelet therapy and endovascular treatment and antiplatelet administration. Poor outcome and mortality rates were significantly reduced among the antiplatelet therapy group.

The impact of aspirin and anticoagulant usage on outcomes after aneurysmal subarachnoid hemorrhage: a Nationwide Inpatient Sample analysis

OBJECTIVE

Although aspirin usage may be associated with a decreased risk of rupture of cerebral aneurysms, any potential therapeutic benefit from aspirin must be weighed against the theoretical risk of greater hemorrhage volume if subarachnoid hemorrhage (SAH) occurs. However, few studies have evaluated the association between prehemorrhage aspirin use and outcomes. This is the first nationwide analysis to evaluate the impact of long-term aspirin and anticoagulant use on outcomes after SAH.

METHODS

Data from the Nationwide Inpatient Sample (NIS; 2006–2011) were extracted. Patients with a primary diagnosis of SAH who underwent microsurgical or endovascular aneurysm repair were included; those with a diagnosis of an arteriovenous malformation were excluded. Multivariable logistic regression was performed to calculate the adjusted odds of in-hospital mortality, a nonroutine discharge (any discharge other than to home), or a poor outcome (death, discharge to institutional care, tracheostomy, or gastrostomy) for patients with long-term aspirin or anticoagulant use. Multivariable linear regression was used to evaluate length of hospital stay. Covariates included patient age, sex, comorbidities, primary payer, NIS-SAH severity scale, intracerebral hemorrhage, cerebral edema, herniation, modality of aneurysm repair, hospital bed size, and whether the hospital was a teaching hospital. Subgroup analyses exclusively evaluated patients treated surgically or endovascularly.

RESULTS

The study examined 11,549 hospital admissions. Both aspirin (2.1%, n = 245) and anticoagulant users (0.9%, n = 108) were significantly older and had a greater burden of comorbid disease (p < 0.001); severity of SAH was slightly lower in those with long-term aspirin use (p = 0.03). Neither in-hospital mortality (13.5% vs 12.6%) nor total complication rates (79.6% vs 80.0%) differed significantly by long-term aspirin use. Additionally, aspirin use was associated with decreased odds of a cardiac complication (OR 0.57, 95% CI 0.36%–0.91%, p = 0.02) or of venous thromboembolic events (OR 0.53, 95% CI 0.30%–0.94%, p = 0.03). Length of stay was significantly shorter (15 days vs 17 days [12.73%], 95% CI 5.22%–20.24%, p = 0.001), and the odds of a nonroutine discharge were lower (OR 0.63, 95% CI 0.48%–0.83%, p = 0.001) for aspirin users. In subgroup analyses, the benefits of aspirin were primarily noted in patients who underwent coil embolization; likewise, among patients treated endovascularly, the adjusted odds of a poor outcome were lower among long-term aspirin users (31.8% vs 37.4%, OR 0.63, 95% CI 0.42%–0.94%, p = 0.03). Although the crude rates of in-hospital mortality (19.4% vs 12.6%) and poor outcome (53.6% vs 37.6%) were higher for long-term anticoagulant users, in multivariable logistic regression models these variations were not significantly different (mortality: OR 1.36, 95% CI 0.89%–2.07%, p = 0.16; poor outcome: OR 1.09, 95% CI 0.69%–1.73%, p = 0.72).

CONCLUSIONS

In this nationwide study, neither long-term aspirin nor anticoagulant use were associated with differential mortality or complication rates after SAH. Aspirin use was associated with a shorter hospital stay and lower rates of nonroutine discharge, with these benefits primarily observed in patients treated endovascularly.

Thromboelastography Parameter Predicts Outcome After Subarachnoid Hemorrhage: An Exploratory Analysis

OBJECTIVE

Hypercoagulability after subarachnoid hemorrhage (SAH) is well described and may be platelet mediated. Thromboelastography (TEG) provides a global assessment of coagulation. We sought to determine whether the maximum amplitude (MA) parameter of TEG, a measure of platelet strength and function, is associated with outcome after SAH.

METHODS

One hundred ten TEG analyses were performed for patients with moderate-to-severe SAH and compared with 6 healthy age- and sex-matched controls. TEG indices included MA, G value (G), alpha angle, and thrombus generation and were correlated to functional outcomes and laboratory tests including complete blood count, erythrocyte sedimentation rate, high sensitivity C-reactive protein, fibrinogen, and d-dimer, obtained on post-bleed days (PBDs) 1, 3, 5, 7, and 10.

RESULTS

MA was significantly elevated compared with controls on PBD 3 (70.0 mm ± 4.5 mm vs. 64.1 mm ± 6.5 mm; P = 0.02), PBD 5 (72.6 mm ± 5.3 mm vs. 64.1 mm ± 6.5 mm; P = 0.003), PBD 7 (73.0 mm ± 5.4 mm vs. 64.1 mm ± 6.5 mm; P = 0.003), and PBD 10 (73.4 mm ± 6.0 mm vs. 64.1 mm ± 6.5 mm; P = 0.005). G was significantly elevated compared with controls on PBD 3 (P = 0.03), PBD 5 (P = 0.01), PBD 7 (P = 0.01), and PBD 10 (P = 0.02). The only biomarker associated with poor outcome was CRP. Multivariate logistic regression demonstrated an association between elevated MA and outcome (odds ratio 39.1, P = 0.006) independent of CRP, age, Hunt Hess grade, and transfusion.

CONCLUSIONS

TEG indices are associated with poor outcome after SAH and may identify a platelet-mediated hypercoagulable state. The association between MA and outcome was stronger than that between traditional biomarkers and was independent of age and Hunt Hess grade.

To look beyond vasospasm in aneurysmal subarachnoid haemorrhage

Delayed cerebral vasospasm has classically been considered the most important and treatable cause of mortality and morbidity in patients with aneurysmal subarachnoid hemorrhage (aSAH). Secondary ischemia (or delayed ischemic neurological deficit, DIND) has been shown to be the leading determinant of poor clinical outcome in patients with aSAH surviving the early phase and cerebral vasospasm has been attributed to being primarily responsible. Recently, various clinical trials aimed at treating vasospasm have produced disappointing results. DIND seems to have a multifactorial etiology and vasospasm may simply represent one contributing factor and not the major determinant. Increasing evidence shows that a series of early secondary cerebral insults may occur following aneurysm rupture (the so-called early brain injury). This further aggravates the initial insult and actually determines the functional outcome. A better understanding of these mechanisms and their prevention in the very early phase is needed to improve the prognosis. The aim of this review is to summarize the existing literature on this topic and so to illustrate how the presence of cerebral vasospasm may not necessarily be a prerequisite for DIND development. The various factors determining DIND that worsen functional outcome and prognosis are then discussed.

Brain ischemia in patients with intracranial hemorrhage: pathophysiological reasoning for aggressive diagnostic management

Patients with intracranial hemorrhage have to be managed aggressively to avoid or minimize secondary brain damage due to ischemia, which contributes to high morbidity and mortality. The risk of brain ischemia, however, is not the same in every patient. The risk of complications associated with an aggressive prophylactic therapy in patients with a low risk of brain ischemia can outweigh the benefits of therapy. Accurate and timely identification of patients at highest risk is a diagnostic challenge. Despite the availability of many diagnostic tools, stroke is common in this population, mostly because the pathogenesis of stroke is frequently multifactorial whereas diagnosticians tend to focus on one or two risk factors. The pathophysiological mechanisms of brain ischemia in patients with intracranial hemorrhage are not yet fully elucidated and there are several important areas of ongoing research. Therefore, this review describes physiological and pathophysiological aspects associated with the development of brain ischemia such as the mechanism of oxygen and carbon dioxide effects on the cerebrovascular system, neurovascular coupling and respiratory and cardiovascular factors influencing cerebral hemodynamics. Consequently, we review investigations of cerebral blood flow disturbances relevant to various hemodynamic states associated with high intracranial pressure, cerebral embolism, and cerebral vasospasm along with current treatment options.

Delayed Cerebral Ischemia After Subarachnoid Hemorrhage

Background and Purpose—

Established predictors of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage are large amounts of extravasated blood and poor clinical condition on admission. The predictive value of other factors is uncertain.

Methods—

We searched MEDLINE (1960–2012) for clinical, laboratory, and radiological predictors routinely available within 72 hours after subarachnoid hemorrhage. The studies were categorized according to methodological quality. Crude data and effect estimates (odds ratio [OR], hazard ratios, and risk ratio) with 95% CI were extracted, (re-)calculated and pooled if possible. For every potential predictor we assessed all effect estimates on consistency (point estimates in equal direction) and clinical relevance (size and 95% CI).

Results—

Fifty-two studies on 33 potential predictors were included. There was strong evidence (≥3 high-quality studies) for a higher risk of delayed cerebral ischemia in smokers (pooled OR, 1.2; 95% CI, 1.1–1.4), and moderate evidence (2 high-quality studies) for an increased risk in patients with hyperglycemia (OR, 3.2; 1.8–5.8 and hazard ratios, 1.7; 1.1–2.5), hydrocephalus (OR, 1.3; 1.1–1.5 and OR, 2.6; 1.2–5.5), history of diabetes mellitus (pooled OR, 6.7; 1.7–26), and early systemic inflammatory response syndrome (pooled OR, 2.1; 1.4–3.3). Evidence was limited for increased risk in women (pooled OR, 1.3; 1.1–1.6) and in patients with history of hypertension (pooled OR, 1.5; 1.3–1.7). The evidence on initial loss of consciousness, history of migraine, previous use of selective serotonin reuptake inhibitors, hypomagnesemia, low hemoglobin, or high blood flow on early transcranial Doppler was also limited.

Conclusions—

There is strong evidence that smoking is a predictor of delayed cerebral ischemia. For several other potential predictions the evidence is moderate, limited, or inconsistent.

Treatment options for cerebral vasospasm in aneurysmal subarachnoid hemorrhage

Cerebral vasospasm occurs frequently after aneurysmal subarachnoid and contributes to delayed cerebral ischemia. In this article we address systematic problems with the literature on vasospasm and then review both established and experimental treatment options.

Early cerebral infarction as a risk factor for poor outcome after aneurysmal subarachnoid haemorrhage

BACKGROUND AND PURPOSE

After aneurysmal subarachnoid haemorrhage, severity of bleeding, and occurrence of rebleeding and cerebral infarcts are the main factors predicting outcome. We investigated predictive risk factors for both early and late cerebral infarcts, and whether time of appearance of infarct is associated with outcome.

METHODS

Previous diseases as well as clinical, laboratory and radiological variables including serial CT scans were recorded for 173 patients admitted within 48 h after bleeding and with ruptured aneurysm occlusion by open surgery within 60 h. Factors predicting occurrence of cerebral infarct and poor outcome at 3 months according to the Glasgow Outcome Scale were tested using multiple logistic regression.

RESULTS

Of several potential predictors, poor outcome was independently predicted by patient age, rebleeding, intraventricular haemorrhage, intracerebral haematoma, delayed cerebral ischaemia with fixed symptoms and early new ischaemic lesion on CT scan appearing on the 1st post-operative morning (P<0.01 for each factor). After adjustment for confounding factors, occurrence of early infarct (odds ratio 12.5; 95% confidence interval 3.2-48.7; P<0.01), both early and late infarct (6.6; 1.1-40.4; P<0.05), and late infarct only (2.4; 0.6-9.1) increased risk for poor outcome. Adjusted independent significant risk factors for early infarction were duration of artery occlusion during surgery (1.4/min; 1.1-1.7, P<0.01) and admission plasma glucose level (1.3 per mM; 1.0-1.6, P<0.05) and for late infarction amount of subarachnoid blood (4.5; 1.3-14.9, P<0.05).

CONCLUSION

Early infarction after surgical aneurysm occlusion seems to have different risk factors and worse prognosis than late infarct which is mostly associated with delayed cerebral ischaemia.

Influence of COX-inhibiting analgesics on the platelet function of patients with subarachnoid hemorrhage

BACKGROUND

Platelet function of patients with subarachnoid hemorrhage (SAH) may play an important part in both rebleeding and delayed cerebral ischemia, but little is known about aggregation pathways during the acute phase of stroke. Analgesics are used regularly in the first days after bleeding, and some can potentially inhibit the cyclooxygenase (COX) enzyme. We examined the platelet function of patients with SAH in order to describe their basal situation and determine whether the administration of intravenous nonsteroidal antiinflammatory drugs (NSAIDs) affected platelet aggregation.

METHODS

Arachidonic acid (AA)-induced aggregation and the platelet function analyzer (PFA)-100 test with collagen/epinephrine cartridges were used to study a group of SAH patients that was treated with dexketoprofen and dipyrone and to compare them to patients that had received no analgesia.

RESULTS

Ninety-six consecutive SAH patients prospectively enrolled in platelet studies. Twenty-seven patients were taking NSAIDs (10 on dexketoprofen and 17 on dipyrone), and there were 15 cases in the control group. AA-induced aggregation was 10% ± 3.2% for NSAIDs (mean ± standard error), specifically 17.2% ± 7% for dexketoprofen and 5.7% ± 1% for dipyrone. Aggregation in the control group was 72.4% ± 6% (P = .001). Both analgesics slowed the platelet plug formation during the PFA-100 test, with closure times of 237.2 ± 25 seconds for dexketoprofen and 198.4 ± 22 seconds for dipyrone and 138.1 ± 21 seconds in controls (P = .02).

CONCLUSIONS

The administration of COX-inhibiting analgesics leads to an hypoaggregability state in the first days of SAH. Further insight into their impact on complications such as rebleeding and delayed cerebral ischemia is needed in order to optimize the headache treatment of SAH.

Metamorphosis of subarachnoid hemorrhage research: from delayed vasospasm to early brain injury

Delayed vasospasm that develops 3–7 days after aneurysmal subarachnoid hemorrhage (SAH) has traditionally been considered the most important determinant of delayed ischemic injury and poor outcome. Consequently, most therapies against delayed ischemic injury are directed towards reducing the incidence of vasospasm. The clinical trials based on this strategy, however, have so far claimed limited success; the incidence of vasospasm is reduced without reduction in delayed ischemic injury or improvement in the long-term outcome. This fact has shifted research interest to the early brain injury (first 72 h) evoked by SAH. In recent years, several pathological mechanisms that activate within minutes after the initial bleed and lead to early brain injury are identified. In addition, it is found that many of these mechanisms evolve with time and participate in the pathogenesis of delayed ischemic injury and poor outcome. Therefore, a therapy or therapies focused on these early mechanisms may not only prevent the early brain injury but may also help reduce the intensity of later developing neurological complications. This manuscript reviews the pathological mechanisms of early brain injury after SAH and summarizes the status of current therapies.

Short-Term Antifibrinolytic Therapy Before Early Aneurysm Treatment in Subarachnoid Hemorrhage: Effects on Rehemorrhage, Cerebral Ischemia, and Hydrocephalus

BACKGROUND:

Long-term administration of the antifibrinolytic agent epsilon aminocaproic acid (EACA) reduces the rate of rehemorrhage in patients with aneurysmal subarachnoid hemorrhage (SAH), but is associated with cerebral ischemia.

OBJECTIVE:

To evaluate short-term administration of EACA before early surgery in patients with SAH.

METHODS:

Retrospective review of 356 patients admitted between June 2002 and December 2007 with a diagnosis of aneurysmal SAH. Medical records were reviewed to determine SAH risk factors, clinical grade at the time of admission, and incidence of rehemorrhage, permanent new-onset focal neurological deficits, computed tomography evidence of cerebral infarction, symptomatic vasospasm, and hydrocephalus.

RESULTS:

Patients underwent treatment of the ruptured aneurysm an average of 47.4 hours after admission and received an average total dose of 40.6 g of EACA. The mean length of time of administration of EACA was 35.6 hours. There was a total of 5 rehemorrhages, for an overall rebleeding rate of 1.4% and a rate of rehemorrhage per 24-hour period of 0.71%. Overall, the rates of symptomatic vasospasm and permanent neurological deficits attributable to ischemic stroke were 11.5% and 7.2%, respectively, and the incidence of shunt-dependent hydrocephalus was 42.3%. Patients who were treated with coiling had higher rates of symptomatic vasospasm and ischemic complications than patients who had surgery.

CONCLUSION:

Short-term administration of EACA is associated with rates of rehemorrhage, ischemic stroke, and symptomatic vasospasm that compare favorably with historical controls. The rate of hydrocephalus is relatively high and may be attributable to EACA treatment.

Elucidating novel mechanisms of brain injury following subarachnoid hemorrhage: an emerging role for neuroproteomics

Subarachnoid hemorrhage (SAH) is a devastating neurological injury associated with significant patient morbidity and death. Since the first demonstration of cerebral vasospasm nearly 60 years ago, the preponderance of research has focused on strategies to limit arterial narrowing and delayed cerebral ischemia following SAH. However, recent clinical and preclinical data indicate a functional dissociation between cerebral vasospasm and neurological outcome, signaling the need for a paradigm shift in the study of brain injury following SAH. Early brain injury may contribute to poor outcome and early death following SAH. However, elucidation of the complex cellular mechanisms underlying early brain injury remains a major challenge. The advent of modern neuroproteomics has rapidly advanced scientific discovery by allowing proteome-wide screening in an objective, nonbiased manner, providing novel mechanisms of brain physiology and injury. In the context of neurosurgery, proteomic analysis of patient-derived CSF will permit the identification of biomarkers and/or novel drug targets that may not be intuitively linked with any particular disease. In the present report, the authors discuss the utility of neuroproteomics with a focus on the roles for this technology in understanding SAH. The authors also provide data from our laboratory that identifies high-mobility group box protein-1 as a potential biomarker of neurological outcome following SAH in humans.

Recurrent perimesencephalic subarachnoid hemorrhage during antithrombotic therapy

INTRODUCTION

In patients with non-aneurysmal perimesencephalic hemorrhage, spontaneous rebleeding does not occur. The lack of reported recurrences may lead to less cautious administration of antithrombotic therapy.

METHODS

Case report.

RESULTS

A 57-year-old woman with a perimesencephalic pattern of hemorrhage and negative CT angiography was treated with carbasalate calcium and intravenous heparin because of an acute coronary syndrome. Three days after installment of this antithrombotic therapy she experienced a recurrent perimesencephalic hemorrhage leading to hydrocephalus and a decrease in consciousness. She died the same day as a result of ventricular fibrillation.

CONCLUSION

In the early phase after perimesencephalic hemorrhage, anticoagulant therapy may lead to rebleeding. The risks and benefits of antithrombotic therapy should be carefully weighed in patients with a perimesencephalic pattern of hemorrhage and negative CT angiography.

Early ischemic lesion on computed tomography: predictor of poor outcome among survivors of aneurysmal subarachnoid hemorrhage

Object

Identifying ischemic lesions after subarachnoid hemorrhage (SAH) is important because the appearance of these lesions on follow-up imaging correlates with a poor outcome. The effect of ischemic lesions seen on computed tomography (CT) scans during the first days of treatment remains unknown, however.

Methods

In 156 patients with SAH, clinical course and outcome, as well as the appearance of ischemic lesions on serial CT scans, were prospectively monitored for 3 months. At 3 months after SAH, magnetic resonance imaging was performed to detect permanent lesions that had not been visible on CT.

Results

Of the 53 patients with no lesions on any of the follow-up CT scans, four (8%) had a poor outcome. Of the 52 patients with a new hypodense lesion on the first postoperative day CT, 23 (44%) had a poor outcome. Among the remaining 51 patients with a lesion appearing later than the first postoperative morning, 10 (20%) had a poor outcome (p < 0.001). After adjusting for patient age; clinical condition on admission; amounts of subarachnoid, intracerebral, and intraventricular blood; and plasma glucose and D-dimer levels, a hypodense lesion on CT on the first postoperative morning was an independent predictor of poor outcome after SAH (odds ratio 7.27, 95% confidence interval 1.54–34.37, p < 0.05).

Conclusions

A new hypodense lesion on early postoperative CT seems to be an independent risk factor for poor outcome after SAH, and this early lesion development may be more detrimental to clinical outcome than a later lesion occurrence.

Antiplatelet therapy for aneurysmal subarachnoid haemorrhage

BACKGROUND

Secondary ischaemia is a frequent cause of poor outcome in patients with aneurysmal subarachnoid haemorrhage (SAH). Besides vasospasm, platelet aggregation seems to play a role in the pathogenesis of secondary ischaemia. Experimental studies have suggested that antiplatelet agents can prevent secondary ischaemia.

OBJECTIVES

To determine whether antiplatelet agents change outcome in patients with aneurysmal SAH.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched August 2006), MEDLINE (1966 to August 2006) and EMBASE databases (1980 to August 2006). We also searched reference lists of identified trials.

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing any antiplatelet agent with control in patients with aneurysmal SAH.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data and assessed trial quality. Relative risks (RR) were calculated with regard to poor outcome, case fatality, secondary ischaemia, haemorrhagic intracranial complications and aneurysmal rebleeding according to the intention-to-treat principle. In case of a statistically significant primary analysis, a worst case analysis was performed.

MAIN RESULTS

Seven RCTs were included in the review, totalling 1385 patients. Four of these trials met the criteria for good quality studies. For any antiplatelet agent there were reductions of a poor outcome (RR 0.79, 95% confidence interval (CI) 0.62 to 1.01) and secondary brain ischaemia (RR 0.79, 95% CI 0.56 to 1.22) and more intracranial haemorrhagic complications (RR 1.36, 95% CI 0.59 to 3.12), but none of these differences were statistically significant. There was no effect on case fatality (RR 1.01, 95% CI 0.74 to 1.37) or aneurysmal rebleeding (RR 0.98, 95% CI 0.78 to 1.38). For individual antiplatelet agents, only ticlopidine was associated with statistically significant fewer occurrences of a poor outcome (RR 0.37, 95% CI 95% CI 0.14 to 0.98) but this estimate was based on only one small RCT.

AUTHORS' CONCLUSIONS

This review shows a trend towards better outcome in patients treated with antiplatelet agents, possibly due to a reduction in secondary ischaemia. However, results were not statistically significant, thus no definite conclusions can be drawn. Also, antiplatelet agents could increase the risk of haemorrhagic complications. On the basis of the current evidence treatment with antiplatelet agents in order to prevent secondary ischaemia or poor outcome cannot be recommended.

Predictors of cerebral infarction in patients with aneurysmal subarachnoid hemorrhage

OBJECTIVE

Cerebral infarction would be expected to be associated with poor outcome after aneurysmal subarachnoid hemorrhage (SAH), although there are few data on which to base this assumption. The goals of this study were to determine the impact of cerebral infarction on outcome and to examine predictors of infarction in these patients.

METHODS

Univariate and multivariable statistical methods were used to examine the impact of cerebral infarction on the Glasgow Outcome Scale score 3 months after SAH among 3567 patients entered into four prospective, randomized, double-blind, placebo-controlled trials of tirilazad conducted in neurosurgical centers around the world between 1991 and 1997. Patient demographics, clinical variables, radiographic characteristics, and treatment variables associated with cerebral infarction were also determined by the same methods.

RESULTS

Seven hundred and seven (26%) out of 2741 patients with complete data had cerebral infarction on computed tomographic scans 6 weeks after SAH. Multivariable logistic regression showed that cerebral infarction increased the odds of unfavorable outcome by a factor of 5.4 (adjusted odds ratio, 5.4; 95% confidence interval, 4.2-6.8; P < 0.0001), which was a higher odds ratio than all other factors associated with outcome. The proportion of explained variance in outcome was also highest for cerebral infarction and accounted for 39% of the explained variance. Multivariable analysis found that cerebral infarction was significantly associated with increasing patient age, worse neurological grade on admission, history of hypertension or diabetes mellitus, larger aneurysm, use of prophylactically or therapeutically induced hypertension, temperature more than 38 degrees C 8 days after SAH, and symptomatic vasospasm.

CONCLUSION

Cerebral infarction was strongly associated with poor outcome after aneurysmal SAH. The most important potentially treatable factor associated with infarction was symptomatic vasospasm.

Vasospasm in aneurysmal subarachnoid hemorrhage: diagnosis, prevention, and management

Cerebral vasospasm is a major cause of morbidity and mortality associated with subarachnoid hemorrhage (SAH). Advances in neuroimaging and development of newer intraparenchymal monitoring devices have improved the prediction and diagnosis of cerebral vasospasm significantly. Recent experimental and clinical trials have increased the armamentarium of preventive and treatment strategies for cerebral vasospasm. Vasospasm refractory to medical therapy usually is treated endovascularly with percutaneous transluminal balloon angioplasty (PTA) for proximal vessel vasospasm and vasodilator infusion for distal vessel vasospasm. Although vasospasm usually does not recur after PTA, recurrence is frequent after vasodilator infusion. The development of newer microballoon catheters has led to improvements in treatment of not only proximal but also distal vessel vasospasm with balloon angioplasty. This article reports on current knowledge in the diagnosis, prediction, prevention, and management of cerebral vasospasm.

Thromboembolism and delayed cerebral ischemia after subarachnoid hemorrhage: an autopsy study

OBJECTIVE

Recent findings have cast doubt on vasospasm as the sole cause of delayed cerebral ischemia after subarachnoid hemorrhage.

METHODS

We reviewed the medical records of 29 patients who died after subarachnoid hemorrhage. Brain sections were taken from the insula, cingulate gyrus, and hippocampus. Adjacent sections were stained with hematoxylin-eosin and immunostained for thromboemboli. The density (burden) of the latter was calculated blindly and correlated with evidence for ischemia and with the amount of subarachnoid blood.

RESULTS

There is a strong correlation between microclot burden and delayed cerebral ischemia. Patients with clinical or radiological evidence of delayed ischemia had mean microclot burdens of 10.0/cm2 (standard deviation [SD], +/-6.6); those without had mean burdens of 2.8 (SD, +/-2.6), a highly significant difference (P = 0.002). There is also significant association (P = 0.001) between microclot burden and histological evidence of ischemia, with the mean burdens being 10.9 in sections exhibiting severe ischemia and 4.1 in those in which ischemia was absent. Microclot burden is high in patients who died within 2 days of hemorrhage, decreasing on Days 3 and 4. In delayed ischemia, the numbers rise again late in the first week and remain high until after the second week. In contrast, the average clot burden is low in patients dying without developing delayed ischemia. The amount of blood on an individual slide influenced the microclot burden on that slide to a highly significant extent (P < 0.001).

CONCLUSION

Thromboembolism after subarachnoid hemorrhage may contribute to delayed cerebral ischemia, which parallels that caused by vasospasm. The pathogenesis of thromboembolism is discussed.

Vasospasm as the sole cause of cerebral ischemia: how strong is the evidence?

✓ The authors review literature that challenges the view that vasospasm involving large arteries is the exclusive cause of delayed ischemic neurological deficits (DINDs) following subarachnoid hemorrhage. They discuss alternative mechanisms and review the evidence supporting a potential role for thromboembolism. They conclude that vasospasm and thromboembolism play interrelated and additive roles in the development of DINDs, and that this interaction provides opportunities for novel therapeutic approaches.

Can angiographic vasospasm be used as a surrogate marker in evaluating therapeutic interventions for cerebral vasospasm?

✓ The authors tested the null hypothesis that published literature with a high level of evidence does not support the assertion that subarachnoid hemorrhage (SAH) causes cerebral vasospasm, which in turn causes cerebral infarction and poor outcome after aneurysmal SAH. The medical literature on SAH was searched in MEDLINE. The author's personal files of all published literature on SAH were reviewed. References cited in Cochrane reviews as well as the published papers that were reviewed were also retrieved.

There is no question that SAH causes what the authors have chosen to call “angiographic vasospasm.” However, the incidence and severity of vasospasm in recent series of patients is not well defined. There is reasonable evidence that vasospasm causes infarction, but again, accurate data on how severe and how diffuse vasospasm has to be to cause infarction and how often vasospasm is the primary cause of infarction are not available. There are good data on the incidence of cerebral infarction after SAH, and these data indicate that it is highly associated with poor outcome. The link between angiographic vasospasm and poor outcome is particularly poorly described in terms of what would be considered data of a high level of evidence.

The question as to whether there is a clear pathway from SAH to vasospasm to cerebral infarction to poor outcome seems so obvious to neurosurgeons as to make it one not worth asking. Nevertheless, the obvious is not always true or accurate, so it is important to note that published literature only weakly supports the causative association of vasospasm with infarction and poor outcome after SAH. It behooves neurosurgeons to document this seemingly straightforward pathway with high-quality evidence acceptable to the proponents of evidence-based medicine.

Randomized controlled trial of acetylsalicylic acid in aneurysmal subarachnoid hemorrhage: the MASH Study

BACKGROUND AND PURPOSE

A previous systematic review of randomized trials suggested a positive effect of antiplatelet therapy in patients with aneurysmal subarachnoid hemorrhage (SAH). We performed a randomized controlled trial to assess whether acetylsalicylic acid (ASA) reduces the risk of delayed ischemic neurological deficit (DIND) in patients with SAH.

METHODS

Criteria for inclusion were aneurysm treatment within 4 days after SAH. Trial medication (14 daily suppositories with 100 mg ASA or placebo) was started within 12 hours after aneurysm treatment. Analysis for the primary outcome event DIND was made according to the "on-treatment" principle and for the secondary outcome measures "poor outcome" and "nonexcellent outcome" according to the "intention-to-treat" principle.

RESULTS

Inclusion was stopped after the second interim analysis, when 161 of the planned 200 patients were included, because by then the chances of a positive effect were negligible. At the final analysis, ASA did not reduce the risk of DIND (hazard ratio, 1.83; 95% CI, 0.85 to 3.9). The relative risk reduction for poor outcome was 21% (relative risk, 0.79; 95% CI, 0.38 to 1.6).

CONCLUSIONS

ASA given after aneurysm treatment does not appreciably reduce the occurrence of DIND.