Angiographic vasospasm versus cerebral infarction as outcome measures after aneurysmal subarachnoid hemorrhage

Effect of Intrathecal Urokinase Infusion on Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Vasospasm following an aneurysmal subarachnoid hemorrhage (SAH) causes serious neurological complications, despite surgical clipping of the aneurysm. Intrathecal urokinase (UK) infusion has been shown to effectively prevent symptomatic vasospasm in patients who have undergone endovascular obliteration of the ruptured aneurysms.

OBJECTIVE

To investigate whether intrathecal UK infusion can prevent symptomatic vasospasm in patients undergoing surgical or endovascular treatment.

METHODS

A total of 90 patients with severe aneurysmal SAH were enrolled and assigned to a surgical neck clipping (n = 56) or an endovascular coil embolization (n = 34) groups. After treatment, UK infusion from the lumbar drain was repeated in 32 patients in the surgical neck clipping group (group B) and all in the endovascular coil embolization group (group C) until complete resolution of the SAH was observed on computed tomography. The remaining 24 of the surgical neck clipping group, without UK infusion, were assigned to group A.

RESULTS

Symptomatic vasospasm occurred in 7 (29.2%) patients in group A, 2 (6.3%) in group B, and none in group C (group A vs. group B [P = 0.02]; group B vs. group C [P = 0.14]). Excellent clinical outcomes (modified Rankin score, 0 or 1) were observed in 37.5%, 59.4%, and 76.5% of patients in group A, B, and C, respectively (group A vs. group B [P = 0.11]).

CONCLUSION

Clearance of SAH via intrathecal UK infusion significantly reduced symptomatic vasospasm in patients in both UK groups, resulting in better clinical outcomes.

Diagnosis of Delayed Cerebral Ischemia in Patients with Aneurysmal Subarachnoid Hemorrhage and Triggers for Intervention

INTRODUCTION

Delayed cerebral ischemia (DCI) is a major determinant for poor neurological outcome after aneurysmal subarachnoid hemorrhage (aSAH). Detection and treatment of DCI is a key component in the neurocritical care of patients with aSAH after initial aneurysm repair.

METHODS

Narrative review of the literature.

RESULTS

Over the past 2 decades, there has been a paradigm shift away from macrovascular (angiographic) vasospasm as a main diagnostic and therapeutic target. Instead, the pathophysiology of DCI is hypothesized to derive from several proischemic pathomechanisms. Clinical examination remains the most reliable means for monitoring and treatment of DCI, but its value is limited in comatose patients. In such patients, monitoring of DCI is usually based on numerous neurophysiological and/or radiological diagnostic modalities. Catheter angiography remains the gold standard for the detection of macrovascular spasm. Computed tomography (CT) angiography is increasingly used instead of catheter angiography because it is less invasive and may be combined with CT perfusion imaging. CT perfusion permits semiquantitative cerebral blood flow measurements, including the evaluation of the microcirculation. It may be used for prediction, early detection, and diagnosis of DCI, with yet-to-prove benefit on clinical outcome when used as a screening modality. Transcranial Doppler may be considered as an additional noninvasive screening tool for flow velocities in the middle cerebral artery, with limited accuracy in other cerebral arteries. Continuous electroencephalography enables detection of early signs of ischemia at a reversible stage prior to clinical manifestation. However, its widespread use is still limited because of the required infrastructure and expertise in data interpretation. Near-infrared spectroscopy, a noninvasive and continuous modality for evaluation of cerebral blood flow dynamics, has shown conflicting results and needs further validation. Monitoring techniques beyond neurological examinations may help in the detection of DCI, especially in comatose patients. However, these techniques are limited because of their invasive nature and/or restriction of measurements to focal brain areas.

CONCLUSION

The current literature review underscores the need for incorporating existing modalities and developing new methods to evaluate brain perfusion, brain metabolism, and overall brain function more accurately and more globally.

Pathophysiology of Early Brain Injury and Its Association with Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage: A Review of Current Literature

Background: Delayed cerebral ischemia (DCI) is a common and serious complication of aneurysmal subarachnoid hemorrhage (aSAH). Though many clinical trials have looked at therapies for DCI and vasospasm in aSAH, along with reducing rebleeding risks, none have led to improving outcomes in this patient population. We present an up-to-date review of the pathophysiology of DCI and its association with early brain injury (EBI). Recent Findings: Recent studies have demonstrated that EBI, as opposed to delayed brain injury, is the main contributor to downstream pathophysiological mechanisms that play a role in the development of DCI. New predictive models, including advanced monitoring and neuroimaging techniques, can help detect EBI and improve the clinical management of aSAH patients. Summary: EBI, the severity of subarachnoid hemorrhage, and physiological/imaging markers can serve as indicators for potential early therapeutics in aSAH. The microcellular milieu and hemodynamic pathomechanisms should remain a focus of researchers and clinicians. With the advancement in understanding the pathophysiology of DCI, we are hopeful that we will make strides toward better outcomes for this unique patient population.

Inhaled Nitric Oxide Treatment for Aneurysmal SAH Patients With Delayed Cerebral Ischemia

Background

We demonstrated experimentally that inhaled nitric oxide (iNO) dilates hypoperfused arterioles, increases tissue perfusion, and improves neurological outcome following subarachnoid hemorrhage (SAH) in mice. We performed a prospective pilot study to evaluate iNO in patients with delayed cerebral ischemia after SAH.

Methods

SAH patients with delayed cerebral ischemia and hypoperfusion despite conservative treatment were included. iNO was administered at a maximum dose of 40 ppm. The response to iNO was considered positive if: cerebral artery diameter increased by 10% in digital subtraction angiography (DSA), or tissue oxygen partial pressure (PtiO₂) increased by > 5 mmHg, or transcranial doppler (TCD) values decreased more than 30 cm/sec, or mean transit time (MTT) decreased below 6.5 secs in CT perfusion (CTP). Patient outcome was assessed at 6 months with the modified Rankin Scale (mRS).

Results

Seven patients were enrolled between February 2013 and September 2016. Median duration of iNO administration was 23 h. The primary endpoint was reached in all patients (five out of 17 DSA examinations, 19 out of 29 PtiO₂ time points, nine out of 26 TCD examinations, three out of five CTP examinations). No adverse events necessitating the cessation of iNO were observed. At 6 months, three patients presented with a mRS score of 0, one patient each with an mRS score of 2 and 3, and two patients had died.

Conclusion

Administration of iNO in SAH patients is safe. These results call for a larger prospective evaluation.

Scoring Model to Predict Functional Outcome in Poor-Grade Aneurysmal Subarachnoid Hemorrhage

Background: Patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH), defined as World Federation of Neurosurgical Societies (WFNS) grades IV–V have high rates of disability and mortality. The objective of this study was to accurately prognosticate the outcomes of patients with poor-grade aSAH by developing a new scoring model.

Methods: A total of 147 poor-grade aSAH patients in our center were enrolled. Risk variables identified by multivariate logistic regression analysis were used to devise a scoring model (total score, 0–9 points). The scores were estimated on the basis of β coefficients. A cohort of 68 patients from another institute was used to validate the model.

Results: Multivariate logistic regression analysis revealed that modified Fisher grade >2 [odds ratio [OR], 2.972; P = 0.034], age ≥65 years (OR, 3.534; P = 0.006), conservative treatment (OR, 5.078; P = 0.019), WFNS grade V (OR, 2.638; P = 0.029), delayed cerebral ischemia (OR, 3.170; P = 0.016), shunt-dependent hydrocephalus (OR, 3.202; P = 0.032), and cerebral herniation (OR, 7.337; P < 0.001) were significant predictors for poor prognosis [modified Rankin Scale [mRS] ≥3]. A scoring system was constructed by the integration of these factors and divided the poor-grade aSAH patients into three categories: low risk (0–1 points), intermediate risk (2–3 points), and high risk (4–9 points), with predicted risks of poor prognosis of 11, 52, and 87%, respectively (P < 0.001). The area under the curve in the derivation cohort was 0.844 (95% CI, 0.778–0.909). The AUC in the validation cohort was 0.831 (95% CI, 0.732–0.929).

Conclusions: The new scoring model can improve prognostication and help decision-making for subsequent complementary treatment in patients with aSAH.

Delayed Ischemic Neurological Deficit after Uneventful Elective Clipping of Unruptured Intracranial Aneurysms

Cerebral vasospasm and subsequent delayed ischemic neurological deficit is a typical sequela of acute subarachnoid hemorrhage after aneurysm rupture. The occurrence of vasospasms after uncomplicated surgery of an unruptured aneurysm without history of suspected rupture is extremely rare. The pathogenesis and severity of cerebral vasospasms is typically correlated with the amount of blood breakdown products extravasated during subarachnoid hemorrhage. In rare cases, where vasospasms occur after unruptured aneurysm surgery, the pathogenesis is most likely multifactorial and unclear. We present two cases of vasospasms following uncomplicated clipping of middle cerebral artery (MCA) aneurysms and a review of literature. Early diagnosis and therapy of this rare complication are necessary to achieve optimal clinical outcomes.

Cerebral artery myogenic reactivity: The next frontier in developing effective interventions for subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is a devastating cerebral event that kills or debilitates the majority of those afflicted. The blood that spills into the subarachnoid space stimulates profound cerebral artery vasoconstriction and consequently, cerebral ischemia. Thus, once the initial bleeding in SAH is appropriately managed, the clinical focus shifts to maintaining/improving cerebral perfusion. However, current therapeutic interventions largely fail to improve clinical outcome, because they do not effectively restore normal cerebral artery function. This review discusses emerging evidence that perturbed cerebrovascular "myogenic reactivity," a crucial microvascular process that potently dictates cerebral perfusion, is the critical element underlying cerebral ischemia in SAH. In fact, the myogenic mechanism could be the reason why many therapeutic interventions, including "Triple H" therapy, fail to deliver benefit to patients. Understanding the molecular basis for myogenic reactivity changes in SAH holds the key to develop more effective therapeutic interventions; indeed, promising recent advancements fuel optimism that vascular dysfunction in SAH can be corrected to improve outcome.

Incidence and Predictors of Angiographic Vasospasm, Symptomatic Vasospasm and Cerebral Infarction in Chinese Patients with Aneurysmal Subarachnoid Hemorrhage

INTRODUCTION

Cerebral vasospasm (CVS) is the most common neurological complication after aneurysmal subarachnoid hemorrhage (aSAH) and associated with poor functional outcome and mortality. Reports on incidence and predictors of CVS in Chinese patients with aSAH were scarce. We aimed to estimate the incidence and predictors of angiographic vasospasm (AV), symptomatic vasospasm (SV), and cerebral infarction in Chinese patients with aSAH.

METHODS

We retrospectively reviewed the medical records of 542 consecutive aSAH patients admitted to neurosurgery department of the First Affiliated Hospital of Xinjiang Medical University in Urumqi city of China between January 1, 2011 and December 31, 2015. AV, SV and cerebral infarction were defined based on clinical data and neuroimaging findings. Univariate and multivariate analyses were performed to identify predictors of AV, SV or cerebral infarction.

RESULTS

343 (63.3%) patients fulfilled the inclusion and exclusion criteria. Of them, 182(53.1%) developed AV, 99 (28.9%) developed SV, and 87 (25.4%) developed cerebral infarction. A history of hypertension, poor modified Fisher grade (3-4) and poor Hunt-Hess grade (4-5) on admission were common risk factors for AV, SV and cerebral infarction. Patients from Uyghur ethnic group or other minorities were less likely to develop AV, SV or cerebral infarction, compared to those from Han ethic group after adjustment of other potential confounders. Additionally, age ≥53 years, leukocyte count ≥11× 109/L on admission and being current or former smokers were independent risk factors of cerebral infarction. Leukocyte count ≥11× 109/L on admission and aneurysm size ≥ 10 mm were independent risk factors of SV. Serum glucose level ≥7.0 mmol/L on admission was an independent risk factor of AV.

CONCLUSION

Risk factors of different definitions of CVS were diverse in Chinese patients with aSAH; however, risk factors of SV and cerebral infarction seem to be similar. We recommend early and aggressive therapy in these patients at-risk of CVS.

Continuous EEG monitoring in aneurysmal subarachnoid hemorrhage: a systematic review

BACKGROUND

Continuous EEG (cEEG) may allow monitoring of patients with aneurysmal subarachnoid hemorrhage (SAH) for delayed cerebral ischemia (DCI) and seizures, including non-convulsive seizures (NCSz), and non-convulsive status epilepticus (NCSE). We aimed to evaluate: (a) the diagnostic accuracy of cEEG as a confirmatory test, (b) the prognostic value of EEG patterns suggestive of seizures and DCI, and (c) the effectiveness of intensified neuromonitoring using cEEG in terms of improved clinical outcome following SAH.

METHODS

A systematic review was performed with eligible studies selected from multiple indexing databases through June 2014. The methodological quality of these studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2.

RESULTS

Eighteen studies were identified, including cEEG data from 481 patients with aneurysmal SAH. NCSz were diagnosed in 7-18 % of patients; NCSE in 3-13 %. NCSE was associated with increased age (mean age 68 years) and mortality (82-100 %) compared to the entire patient population (53.9 years; mortality 13 %; p values <0.05). DCI was diagnosed in 20-46 % of patients. Quantitative EEG patterns suggestive of DCI included decreased alpha/delta ratio, relative alpha variability, and total power. All studies were subject to a high risk of bias concerning patient selection and cEEG methodology.

CONCLUSIONS

cEEG monitoring following SAH detects an increased number of subclinical seizures and may predict DCI many hours in advance. NCSE is associated with high mortality and morbidity, whereas for DCI identified by cEEG this association is less clear. Prospective randomized controlled multicenter trials are needed to evaluate the benefits (or risks) of intensified treatment of seizures and DCI following SAH.

Subarachnoid hemorrhage: who dies, and why?

Introduction

Subarachnoid hemorrhage (SAH) is a devastating form of stroke. Causes and mechanisms of in-hospital death after SAH in the modern era of neurocritical care remain incompletely understood.

Methods

We studied 1200 consecutive SAH patients prospectively enrolled in the Columbia University SAH Outcomes Project between July 1996 and January 2009. Analysis was performed to identify predictors of in-hospital mortality.

Results

In-hospital mortality was 18 % (216/1200): 3 % for Hunt-Hess grade 1 or 2, 9 % for grade 3, 24 % for grade 4, and 71 % for grade 5. The most common adjudicated primary causes of death or neurological devastation leading to withdrawal of support were direct effects of the primary hemorrhage (55 %), aneurysm rebleeding (17 %), and medical complications (15 %). Among those who died, brain death was declared in 42 %, 50 % were do-not-resuscitate at the time of cardiac death (86 % of whom had life support actively withdrawn), and 8 % died despite full support. Admission predictors of mortality were age, loss of consciousness at ictus, admission Glasgow Coma Scale score, large aneurysm size, Acute Physiology and Chronic Health Evaluation II (APACHE II) physiologic subscore, and Modified Fisher Scale score. Hospital complications that further increased the risk of dying in multivariable analysis included rebleeding, global cerebral edema, hypernatremia, clinical signs of brain stem herniation, hypotension of less than 90 mm Hg treated with pressors, pulmonary edema, myocardial ischemia, and hepatic failure. Delayed cerebral ischemia, defined as deterioration or infarction from vasospasm, did not predict mortality.

Conclusion

Strategies directed toward minimizing early brain injury and aneurysm rebleeding, along with prevention and treatment of medical complication, hold the best promise for further reducing mortality after SAH.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1036-0) contains supplementary material, which is available to authorized users.

Effect of endothelin receptor antagonists on clinically relevant outcomes after experimental subarachnoid hemorrhage: a systematic review and meta-analysis

In clinical trials, endothelin receptor antagonists (ETRAs) reduced vasospasm but did not improve functional outcome after subarachnoid hemorrhage (SAH). We assessed the effects of treatment with ETRAs on clinically relevant outcomes in animal studies modelling SAH by performing a systematic review of the literature for controlled animal studies of ETRAs for the treatment of SAH. Primary outcomes were neurobehavioral outcomes and case fatality. Secondary outcomes were cerebral vasospasm and cerebral blood flow. Summary estimates were calculated using normalized mean difference random effects meta-analysis. We included 27 studies (55 experiments, 639 animals). Neurobehavioral scores were reported in none of the experiments, and case fatality in 8 (15%). Treatment with ETRAs was associated with a pooled odds ratio for case fatality of 0.61 (95% confidence interval (CI), 0.27 to 1.39); a 54% increase (95% CI, 39 to 69) in cerebral arterial diameter; and a 93% increase (95% CI, 58 to 129) in cerebral blood flow. We conclude that there is no evidence from animal studies that treatment with an ETRA improves clinically relevant outcomes after SAH. The reduction in cerebral vasospasm observed in animal studies is consistent with that observed in clinical trials, an effect that is not associated with better functional outcome in patients.

Redefining secondary injury after subarachnoid hemorrhage in light of multimodal advanced neuroimaging, intracranial and transcranial neuromonitoring: beyond vasospasm

The classic idea that arterial narrowing, called vasospasm (VSP), represents the hallmark of secondary injury after subarachnoid hemorrhage, has been challenged. The more complex and pleiotropic pathophysiological repercussions from the irruption of arterial blood into the subarachnoid layers go beyond the ascribed VSP. Putting adjectives in front of this term, such as "symptomatic," "microdialytic," or "angiographic" VSP, is misleading. Delayed cerebral ischemia (DCI) is a better term but remains restrictive to severe hypoperfusive injury and neglects oligemia, edema, and metabolic nonischemic injuries. In recognition of these issues, the international conference on VSP integrated "neurovascular events" into its name ( www.vasospasm2013.com ) and a multidisciplinary research group was formed in 2010 to study subgroups of DCI/VSP and their respective significance.In three parts, this tiered article provides a broader definitional envelope for DCI and secondary neurovascular insults after SAH, with a rubric for each subtype of delayed neuronal dysfunction. First, it pinpoints the need for nosologic precision and covers current terminological inconsistency. Then, it highlights the input of neuroimaging and neuromonitoring in defining secondary injurious processes. Finally, a new categorization of deteriorating patients is proposed, going beyond a hierarchical or dichotomized definition of VSP/DCI, and common data elements are suggested for future trials.

Delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage: proposal of an evidence-based combined clinical and imaging reference standard

SUMMARY

Aneurysmal subarachnoid hemorrhage is associated with high morbidity and mortality, with delayed neurologic deficits from delayed cerebral ischemia contributing to a large portion of the adverse outcomes in this patient population. There is currently no consensus reference standard for establishing the diagnosis of delayed cerebral ischemia either in the research or clinical settings, ultimately limiting strategies for preventing delayed infarction and permanent neurologic deficits. There are currently both clinical and imaging-based criteria for the diagnosis of delayed neurologic deficits and vasospasm, respectively, however, neither clinical nor angiographic assessment alone has been shown to identify patients who develop adverse outcomes from delayed infarction. Thus, the purpose of this work is to propose a 3-tiered combined imaging and clinical reference standard based on evidence from the literature to standardize the diagnosis of delayed cerebral ischemia, both to allow consistency across research studies and to ultimately improve outcomes in the clinical setting.

Low-dose intravenous heparin infusion in patients with aneurysmal subarachnoid hemorrhage: a preliminary assessment

OBJECT

Aneurysmal subarachnoid hemorrhage (aSAH) predisposes to delayed neurological deficits, including stroke and cognitive and neuropsychological abnormalities. Heparin is a pleiotropic drug that antagonizes many of the pathophysiological mechanisms implicated in secondary brain injury after aSAH.

METHODS

The authors performed a retrospective analysis in 86 consecutive patients with Fisher Grade 3 aSAH due to rupture of a supratentorial aneurysm who presented within 36 hours and were treated by surgical clipping within 48 hours of their ictus. Forty-three patients were managed postoperatively with a low-dose intravenous heparin infusion (Maryland low-dose intravenous heparin infusion protocol: 8 U/kg/hr progressing over 36 hours to 10 U/kg/hr) beginning 12 hours after surgery and continuing until Day 14 after the ictus. Forty-three control patients received conventional subcutaneous heparin twice daily as deep vein thrombosis prophylaxis.

RESULTS

Patients in the 2 groups were balanced in terms of baseline characteristics. In the heparin group, activated partial thromboplastin times were normal to mildly elevated; no clinically significant hemorrhages or instances of heparin-induced thrombocytopenia or deep vein thrombosis were encountered. In the control group, the incidence of clinical vasospasm requiring rescue therapy (induced hypertension, selective intraarterial verapamil, and angioplasty) was 20 (47%) of 43 patients, and 9 (21%) of 43 patients experienced a delayed infarct on CT scanning. In the heparin group, the incidence of clinical vasospasm requiring rescue therapy was 9% (4 of 43, p = 0.0002), and no patient suffered a delayed infarct (p = 0.003).

CONCLUSIONS

In patients with Fisher Grade 3 aSAH whose aneurysm is secured, postprocedure use of a low-dose intravenous heparin infusion may be safe and beneficial.

Calcium and potassium channels in experimental subarachnoid hemorrhage and transient global ischemia

Healthy cerebrovascular myocytes express members of several different ion channel families which regulate resting membrane potential, vascular diameter, and vascular tone and are involved in cerebral autoregulation. In animal models, in response to subarachnoid blood, a dynamic transition of ion channel expression and function is initiated, with acute and long-term effects differing from each other. Initial hypoperfusion after exposure of cerebral vessels to oxyhemoglobin correlates with a suppression of voltage-gated potassium channel activity, whereas delayed cerebral vasospasm involves changes in other potassium channel and voltage-gated calcium channels expression and function. Furthermore, expression patterns and function of ion channels appear to differ between main and small peripheral vessels, which may be key in understanding mechanisms behind subarachnoid hemorrhage-induced vasospasm. Here, changes in calcium and potassium channel expression and function in animal models of subarachnoid hemorrhage and transient global ischemia are systematically reviewed and their clinical significance discussed.