Racial differences in cerebral vasospasm: a systematic review of the literature

Endoscopic Eyebrow Approach for Aneurysms

INTRODUCTION

Considerable effort has been made to reduce surgical invasiveness, since Axel Perneczky introduced the supraorbital eyebrow approach as a core part of his keyhole concept in neurosurgery. But a limited approach does not facilitate an already serious and demanding task as aneurysm surgery. In this regard, the enhancement of the visual field before, during, and after microsurgical aneurysm occlusion is a safe and effective method to increase the quality of treatment. Indications/Contraindications: Based on the individual anatomical findings, the supraorbital keyhole approach provides access to most aneurysms of the anterior circulation. The approach is not recommended in large complex aneurysms, giant aneurysms, BA aneurysms located beneath the dorsum sellae, as well as cases of severe subarachnoid hemorrhage (SAH) and expected brain edema.

COMPLICATIONS

Experience with endoscopic procedures in aneurysm surgery is limited to several clinical retrospective articles, and no major complications in conjunction with the endoscope were observed. Outcome and Prognosis: The supraorbital eyebrow approach has a low rate of complications and provides highly favorable cosmetic results. Endoscopic inspection prior to clipping might reduce overexposure and mobilization of the aneurysm. It was found that the rate of intraoperative rupture was decreased. The endoscopic post-clipping control helped significantly to reduce aneurysm remnants and unattended parent, branch, or perforator occlusion.

CONCLUSION

The supraorbital eyebrow approach is a safe, effective and elegant approach in the treatment of most aneurysms of the anterior circulation. The additional enhancement of the visual field provided by the endoscope before, during, and after microsurgical aneurysm clipping might decrease the rate of intraoperative aneurysm ruptures and unexpected findings concerning aneurysm remnant occlusion and compromise of involved parent, branching, and perforating vessels.

Risk Factors for Cerebral Vasospasm in Patients with Aneurysmal Subarachnoid Hemorrhage: A Tertiary Care Center Experience

Objectives  Cerebral vasospasm in subarachnoid hemorrhage (SAH) is associated with high morbidity and mortality. There is a lack of consensus on the risk factors leading to cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage (aSAH). In this retrospective study, our objective was to determine the association of risk factors for cerebral vasospasm aSAH.

Methods  A total of 259 charts of aSAH patients consecutively admitted to the surgical intensive care unit of Hamad General Hospital from January 2007 to December 2016 were reviewed and included. The patient's demographic data, including comorbidities like hypertension (HTN), was recorded. Variables of interest included measurements of the neurological deficit on admission, the severity of SAH, treatment modality, and the initial computerized tomography scan of the head for intraventricular hemorrhage, intracerebral hemorrhage, or hydrocephalus. Multivariate analysis and multiple logistic regression analyzed the relationship to identify the association of independent variables.

Results  Out of the 259 patients, 34% ( n  = 87) suffered from cerebral vasospasm. The severity of SAH was associated with the development of cerebral vasospasm ( p  < 0.05). The presence of HTN and neurological deficits on admission were associated with an increased risk of cerebral vasospasm ( p  < 0.05, p  < 0.01, respectively). Hydrocephalus requiring treatment using external ventricular drains decreased the risk of cerebral vasospasm ( p  < 0.05). Intraventricular and intracerebral hemorrhage were not associated with cerebral vasospasm ( p  = 0.25, p  = 0.16). The endovascular treatment of cerebral aneurysms was associated with an increased risk of cerebral vasospasm ( p  < 0.05).

Conclusion  Cerebral vasospasm is common among patients admitted with aSAH. It is significantly associated with the history of HTN, the neurological deficit on admission that corelates more strongly to the motor deficit on admission, the severity of hemorrhage (modified Fischer score), and endovascular treatment. External ventricular drainage was associated with a decrease in cerebral vasospasm. The present study's findings shed light on cerebral vasospasm's risk factors in the country and the region.

Blood-Related Toxicity after Traumatic Brain Injury: Potential Targets for Neuroprotection

Emergency visits, hospitalizations, and deaths due to traumatic brain injury (TBI) have increased significantly over the past few decades. While the primary early brain trauma is highly deleterious to the brain, the secondary injury post-TBI is postulated to significantly impact mortality. The presence of blood, particularly hemoglobin, and its breakdown products and key binding proteins and receptors modulating their clearance may contribute significantly to toxicity. Heme, hemin, and iron, for example, cause membrane lipid peroxidation, generate reactive oxygen species, and sensitize cells to noxious stimuli resulting in edema, cell death, and increased morbidity and mortality. A wide range of other mechanisms such as the immune system play pivotal roles in mediating secondary injury. Effective scavenging of all of these pro-oxidant and pro-inflammatory metabolites as well as controlling maladaptive immune responses is essential for limiting toxicity and secondary injury. Hemoglobin metabolism is mediated by key molecules such as haptoglobin, heme oxygenase, hemopexin, and ferritin. Genetic variability and dysfunction affecting these pathways (e.g., haptoglobin and heme oxygenase expression) have been implicated in the difference in susceptibility of individual patients to toxicity and may be target pathways for potential therapeutic interventions in TBI. Ongoing collaborative efforts are required to decipher the complexities of blood-related toxicity in TBI with an overarching goal of providing effective treatment options to all patients with TBI.

Prevalence of Normal-Tension Glaucoma in the Chinese Population: A Systematic Review and Meta-Analysis

PURPOSE

To investigate the prevalence of normal-tension glaucoma (NTG) in the Chinese population through systematic review and meta-analysis.

DESIGN

Systematic review and meta-analysis.

METHODS

All Chinese population-based studies that reported the prevalence of NTG were identified. We searched PubMed and Chinese databases including Wanfang, China National Knowledge Infrastructure, and VIP for studies published before December 31, 2017. Random effects meta-analysis was conducted to estimate the pooled prevalence of NTG.

RESULTS

Twelve studies were included in this review and meta-analysis, including 9 population-based studies and 3 studies from glaucoma clinics and managed care networks. The 9 population-based studies included a total of 30,892 subjects with 498 patients with primary open-angle glaucoma (POAG) and 354 patients with NTG. The prevalence of estimated NTG ranged from 0.36% to 1.98% and the percentage of NTG among POAG ranged from 51.43% to 83.58%. In the glaucoma clinic and managed care network studies, NTG prevalence was much lower. The overall pooled proportion of NTG among POAG in the Chinese population was 70.0% (95% confidence interval [CI] 62.0-77.0%). The overall pooled prevalence of POAG and NTG was 2.0% (95% CI 1.0-2.0%) and 1.0% (95% CI 1.0-1.0%), respectively. For the meta-regression of the NTG/POAG proportion, we found that age, gender, intraocular pressure, and China versus not China were not significantly associated with NTG/POAG prevalence, although the proportional prevalence decreased with increasing age category.

CONCLUSIONS

In this systematic review, we found that NTG is common among patients with POAG in the Chinese population. Our findings can help guide future glaucoma studies and public health guidelines in the Chinese population.

Intraoperative Measurement of Arterial Blood Flow in Aneurysm Surgery

Intraoperative flowmetry (IF) has been recently introduced during cerebral aneurysm surgery in order to obtain a safer surgical exclusion of the aneurysm. This study evaluates the usefulness of IF during surgery for cerebral aneurysms and compares the results obtained in the joined surgical series of Verona and Padua to the more recent results obtained at the neurosurgical department of Verona.In the first surgical series, between 2001 and 2010, a total of 312 patients were submitted to IF during surgery for cerebral aneurysm at the neurosurgical departments of Verona and Padua: 162 patients presented with subarachnoid hemorrhage (SAH) whereas 150 patients harbored unruptured aneurysms. In the second series, between 2011 and 2016, 112 patients were submitted to IF during surgery for cerebral aneurysm at the neurosurgical department of Verona; 24 patients were admitted for SAH, whereas 88 patients were operated on for unruptured aneurysms.Comparison of the baseline values in the two surgical series and the baseline values between unruptured and ruptured aneurysms showed no statistical differences between the two clinical series. Analysis of flowmetry measurements showed three types of loco-regional flow derangements: hyperemia after temporary arterial occlusion, redistribution of flow in efferent vessels after clipping, and low flow in patients with SAH-related vasospasm.IF provides real-time data about flow derangements caused by surgical clipping of cerebral aneurysm, thus enabling the surgeon to obtain a safer exclusion; furthermore, it permits the evaluation of other effects of clipping on the loco-regional blood flow. It is suggested that-in contribution with intraoperative neurophysiological monitoring-IF may now constitute the most reliable tool for increasing safety in aneurysm surgery.

Predictors of Postoperative Cerebral Ischemia in Patients with Ruptured Anterior Communicating Artery Aneurysms

OBJECTIVE

Cerebral ischemia is a major contributor to poor outcome after ruptured anterior communicating artery aneurysms (ACoAs), and is not well classified. In this article, we develop a classification and identify risk factors of cerebral ischemia after ruptured ACoAs.

METHODS

Three hundred sixty patients with ruptured ACoAs undergoing microsurgical clipping were collected. Sex, age, smoking status, Hunt-Hess grade, Fisher grade, hospital stay, surgical timing, hypertension, diabetes, postoperative cerebral ischemia, and postoperative modified Rankin Scale score were collected. Postoperative ischemic changes are classified according to a novel grade (ischemic grade I-IV).

RESULTS

Predictive factors of postoperative ischemia (grade I-IV) included sex (odds ratio [OR], 1.956; 95% confidence interval [CI], 1.262-3.032; P = 0.003) and Fisher grade (OR, 1.813; 95% CI, 1.144-2.871; P = 0.011). Male sex had a tendency to develop postoperative cerebral ischemia (61.3% in the ischemia group vs. 45.7% in the nonischemia group), while surgical timing did not. However, in patients with postoperative ischemia, early surgery within 3 days (OR, 3.334; 95% CI, 1.411-7.879; P = 0.006) and advanced age greater than 55 years (OR, 2.783; 95% CI, 1.214-6.382; P = 0.016) were risk factors for postoperative neurologic deficits (grade III-IV).

CONCLUSIONS

Male sex and higher Fisher grade predict postoperative ischemia (grade I-IV), whereas surgical timing does not. However, in patients with postoperative cerebral ischemia, early surgery within 3 days and age greater than 55 years can increase the frequency of postoperative neurological deficits (grade III-IV). Older male patients undergoing early microsurgery had a tendency to develop neurologic deficits.

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.

Risk Factors for Cerebral Vasospasm Following Aneurysmal Subarachnoid Hemorrhage: A Review of the Literature

OBJECTIVE

To examine the literature on risk factors for cerebral vasospasm (CV), one of the most serious complications following aneurysmal subarachnoid hemorrhage (SAH), with special reference to the definition of CV.

METHODS

Using standard search engines, including PubMed, the medical literature on risk factors for CV after SAH was reviewed, and the best definition representative of CV was searched.

RESULTS

Severe SAH evident on computed tomography scan was the only consistent risk factor for CV after SAH. Effects of risk factors on CV, including age, clinical grade, rebleeding, intraventricular or intracerebral hemorrhage on computed tomography scan, acute hydrocephalus, aneurysm site and size, leukocytosis, interleukin-6 level, and cardiac abnormalities, appeared to be associated with the severity of SAH rather than each having a direct effect. Cigarette smoking, hypertension, and left ventricular hypertrophy on electrocardiogram were associated with CV without any relationship to SAH severity. With regard to parameters representative of CV, the grade of angiographic vasospasm (i.e., the degree of arterial narrowing evident on angiography) was the most adequate. Nevertheless, few reports on the risk factors associated with angiographic vasospasm grade have been reported to date.

CONCLUSIONS

Severe SAH evident on computed tomography scan appears to be a definite risk factor for CV after SAH, followed by cigarette smoking, hypertension, and left ventricular hypertrophy on electrocardiogram. To understand the pathogenesis of CV, further studies on the relationships between risk factors, especially factors not related to the severity of SAH, and angiographic vasospasm grade are necessary.

Cerebral Vasospasm: A Review

Cerebral vasospasm is a prolonged but reversible narrowing of cerebral arteries beginning days after subarachnoid hemorrhage. Progression to cerebral ischemia is tied mostly to vasospasm severity, and its pathogenesis lies in artery encasement by blood clot, although the complex interactions between hematoma and surrounding structures are not fully understood. The delayed onset of vasospasm provides a potential opportunity for its prevention. It is disappointing that recent randomized, controlled trials did not demonstrate that the endothelin antagonist clazosentan, the cholesterol-lowering agent simvastatin, and the vasodilator magnesium sulfate improve patient outcome. Minimizing ischemia by avoiding inadequate blood volume and pressure, administering the calcium antagonist nimodipine, and intervention with balloon angioplasty, when necessary, constitutes current best management. Over the past two decades, our ability to manage vasospasm has led to a significant decline in patient morbidity and mortality from vasospasm, yet it still remains an important determinant of outcome after aneurysm rupture.

Evaluating blood-brain barrier permeability in delayed cerebral infarction after aneurysmal subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Patients with SAH are at increased risk of delayed infarction. Early detection and treatment of delayed infarction remain challenging. We assessed blood-brain barrier permeability, measured as permeability surface area product, by using CTP in patients with SAH with delayed infarction.

MATERIALS AND METHODS

We performed a retrospective study of patients with SAH with delayed infarction on follow-up NCCT. CTP was performed before the development of delayed infarction. CTP data were postprocessed into permeability surface area product, CBF, and MTT maps. Coregistration was performed to align the infarcted region on the follow-up NCCT with the corresponding location on the CTP maps obtained before infarction. Permeability surface area product, CBF, and MTT values were then obtained in the location of the subsequent infarction. The contralateral noninfarcted region was compared with the affected side in each patient. Wilcoxon signed rank tests were performed to determine statistical significance. Clinical data were collected at the time of CTP and at the time of follow-up NCCT.

RESULTS

Twenty-one patients with SAH were included in the study. There was a statistically significant increase in permeability surface area product in the regions of subsequent infarction compared with the contralateral control regions (P < .0001). However, CBF and MTT values were not significantly different in these 2 regions. Subsequent follow-up NCCT demonstrated new delayed infarction in all 21 patients, at which time 38% of patients had new focal neurologic deficits.

CONCLUSIONS

Our study reveals a statistically significant increase in permeability surface area product preceding delayed infarction in patients with SAH. Further investigation of early permeability changes in SAH may provide new insights into the prediction of delayed infarction.

Decreased endothelin-1 plasma levels in multiple sclerosis patients: a possible factor of vascular dysregulation?

BACKGROUND

Multiple sclerosis (MS) is a demyelinating autoimmune disease of the central nervous system with possible involvement of vascular dysregulation secondary to endothelial dysfunction caused by destruction of the vessel wall. Vascular dysregulation leads to excessive vasoconstriction or insufficient vasodilatation, resulting in vasospasm mediated by endothelin-1 (ET-1), the most potent and long-lasting mediator. Vascular dysregulation can play an important role in the pathogenesis of some eye disorders and it has been hypothesized that it is a vascular risk factor for glaucomatous optic neuropathy. The aim of this study was to estimate endothelin-1 (ET-1) plasma levels in patients with MS.

MATERIAL AND METHODS

The MS group consisted of 39 patients (9 males, 30 females), mean age: 38.8 ± 10.02 years, range: 22-62. The control group consisted of 27 healthy volunteers (3 males and 24 females), mean age: 37.4 ± 10.88 years, range: 20-62; clinically, in a non-active stage of the disease. ET-1 plasma levels were measured using the Endothelin-1 ELISA Kit (Immuno-Biological Laboratories Co., Japan). Statistical analysis was performed with the nonparametric Mann-Whitney U test for independent groups.

RESULTS

Endothelin-1 (ET-1) plasma levels were significantly lower in MS patients compared to healthy controls: mean value 0.55 ± 0.44 pg/ml (146.05 ± 118.27 fmol/ml) vs. 0.95 ± 0.48 pg/ml (252.83 ± 127.16 fmol/ml); P=0.012.

CONCLUSIONS

Significantly decreased ET-1 plasma levels in the MS patients could reflect the non-active disease at the time of ET-1 measurements or the effects of immunomodulatory treatment, but it cannot be excluded that decreased ET-1 plasma levels in these patients might result from vascular dysregulation.

Clinical prediction models for aneurysmal subarachnoid hemorrhage: a systematic review

BACKGROUND

Clinical prediction models can enhance clinical decision-making and research. However, available prediction models in aneurysmal subarachnoid hemorrhage (aSAH) are rarely used. We evaluated the methodological validity of SAH prediction models and the relevance of the main predictors to identify potentially reliable models and to guide future attempts at model development.

METHODS

We searched the EMBASE, MEDLINE, and Web of Science databases from January 1995 to June 2012 to identify studies that reported clinical prediction models for mortality and functional outcome in aSAH. Validated methods were used to minimize bias.

RESULTS

Eleven studies were identified; 3 developed models from datasets of phase 3 clinical trials, the others from single hospital records. The median patient sample size was 340 (interquartile range 149-733). The main predictors used were age (n = 8), Fisher grade (n = 6), World Federation of Neurological Surgeons grade (n = 5), aneurysm size (n = 5), and Hunt and Hess grade (n = 3). Age was consistently dichotomized. Potential predictors were prescreened by univariate analysis in 36 % of studies. Only one study was penalized for model optimism. Details about model development were often insufficiently described and no published studies provided external validation.

CONCLUSIONS

While clinical prediction models for aSAH use a few simple predictors, there are substantial methodological problems with the models and none have had external validation. This precludes the use of existing models for clinical or research purposes. We recommend further studies to develop and validate reliable clinical prediction models for aSAH.

Genetics of cerebral vasospasm

Cerebral vasospasm (CV) is a major source of morbidity and mortality in aneurysmal subarachnoid hemorrhage (aSAH). It is thought that an inflammatory cascade initiated by extravasated blood products precipitates CV, disrupting vascular smooth muscle cell function of major cerebral arteries, leading to vasoconstriction. Mechanisms of CV and modes of therapy are an active area of research. Understanding the genetic basis of CV holds promise for the recognition and treatment for this devastating neurovascular event. In our review, we summarize the most recent research involving key areas within the genetics and vasospasm discussion: (1) Prognostic role of genetics—risk stratification based on gene sequencing, biomarkers, and polymorphisms; (2) Signaling pathways—pinpointing key inflammatory molecules responsible for downstream cellular signaling and altering these mediators to provide therapeutic benefit; and (3) Gene therapy and gene delivery—using viral vectors or novel protein delivery methods to overexpress protective genes in the vasospasm cascade.

Vasospasm after aneurysmal subarachnoid hemorrhage: recent advances in endovascular management

PURPOSE OF REVIEW

In a rapidly advancing specialty, it is essential to review the recent studies of alternative new treatments and present their efficacy, safety and outcome. We discuss the recent advances in the endovascular treatment of cerebral vasospasm following aneurysmal subarachnoid hemorrhage in the past few years with special focus on the literature regarding this subject in the last 18-24 months.

RECENT FINDINGS

The recent findings are as follows: effect of papaverine on brain oxygen; recent evaluation concerning nimodipine use; combined intraarterial and intravenous use of milrinone; illustration of the numerous recent studies on nicardipine; the safety and efficacy of high-dose intraarterial verapamil; outcome and adverse effects of intraarterial fasudil; transluminal balloon angioplasty; and recent evaluation of its efficacy and evaluation of its prophylactic use.

SUMMARY

Endovascular treatment, including intraarterial vasodilators and transluminal balloon angioplasty, has a very important place in the management of symptomatic vasospasm related to aneurysmal subarachnoid hemorrhage. The efficacy of intraarterial vasodilators has been proven. Numerous studies and analysis of different treatments of cerebrovascular vasospasm took place in the past period. This allowed more understanding and evaluation of their outcome, safety and efficacy helping physicians to choose better treatments to adopt. It emphasizes also the aspects that need more study and research.

New insights in the pathogenesis and treatment of normal tension glaucoma

Increased intraocular pressure (IOP) is a major risk factor for glaucomatous damage and reducing IOP improves prognosis. Nevertheless, there is little doubt that other risk factors besides IOP such as unstable ocular perfusion are involved. Blood flow is unstable if either the IOP fluctuates at a high level (or blood pressure fluctuates at a low level) or if the autoregulation of blood flow disturbed. A common cause for a disturbed OBF autoregulation is a primary vascular dysregulation (PVD) frequently observed in normal tension glaucoma patients. An unstable blood flow leads to recurrent mild reperfusion injury (chronic oxidative stress) affecting particularly the mitochondria of the optic nerve head. OBF regulation can be improved by magnesium, calcium channel blockers as well as with carbonic anhydrase inhibitors.

Flow replacement bypass for aneurysms: decision-making using intraoperative blood flow measurements

PURPOSE

There is much debate regarding the optimal strategy for extracranial-intracranial (EC-IC) bypass for complex aneurysms. We introduce the concept of a flow replacement bypass which aims to compensate for loss of flow in the efferent vessels of the aneurysm. The strategy to achieve this utilizes direct intraoperative flow measurements to guide optimal revascularization by matching graft flow to demand.

METHODS

We reviewed all EC-IC bypass cases performed over a 6-year period. We identified cases in which intraoperative flow measurements using an ultrasonic flow probe were utilized to determine the revascularization strategy and analyzed the decision-making paradigm.

RESULTS

Twenty-three cases were analyzed. For terminal aneurysms, flow measurement in the affected vessel at baseline predicted the flow required for full replacement: middle cerebral artery (MCA), 50 +/- 25 cc/min (n = 9); posterior inferior cerebellar artery (PICA), 13 +/- 7 cc/min (n = 4); posterior cerebral artery (PCA), 33 cc/min (n = 1); and superior cerebellar artery (SCA), 10 cc/min (n = 1). For proximal internal carotid artery (ICA) aneurysms (n = 8), the flow deficit from baseline during carotid temporary occlusion was measured (26 +/- 18 cc/min, an average of 44% drop from baseline). The adequacy of flow from the superficial temporal artery (STA) or occipital artery (OA), when available, was assessed prior to bypass, and STA, OA, or vein interposition grafts were used accordingly. Measurement of bypass flow following anastomosis confirmed not only patency but sufficient flow in all cases: MCA 50 +/- 25 cc/min, PICA 18 +/- 9 cc/min, PCA 64 cc/min, SCA 12 cc/min, ICA 36 +/- 25 cc/min (STA), and >200 cc/min (vein).

CONCLUSIONS

Direct intraoperative measurement of flow deficit in aneurysm surgery requiring parent vessel sacrifice can guide the choice of flow replacement graft and confirm the subsequent adequacy of bypass flow.

Association of a younger age with an increased risk of angiographic and symptomatic vasospasms following subarachnoid hemorrhage

Object

Vasospasm is a leading cause of morbidity and death following aneurysmal subarachnoid hemorrhage (SAH). It is important to predict which patients are at risk for vasospasm so that interventions can be made. There are several potential risk factors for vasospasm, one of which is age. However, the effect of age on vasospasm, particularly symptomatic vasospasm, remains controversial.

Methods

Three hundred ninety-one patients were retrospectively identified from a prospective observational database of patients with SAH who had been admitted to a single center. Demographic and clinical data were recorded, and cerebral angiograms obtained at admission and between 5 and 10 days later were compared. The relationship between age and angiographic and symptomatic vasospasms was examined using logistic regression techniques.

Results

Mild (86 patients), moderate (69 patients), severe (56 patients), and no angiographic vasospasms (180 patients) were documented by comparing admission and follow-up angiograms in each patient. Symptomatic vasospasm was identified in 69 patients (17.6%). Angiographic vasospasm was more frequent as age decreased. Except in patients < 30 years old, the frequency of symptomatic vasospasm also increased with decreasing age (p = 0.0001). After adjusting for variables known to be associated with vasospasm, an advanced age was associated with a reduced incidence of any angiographic vasospasm (OR 0.96, 95% CI 0.94–0.97), severe angiographic vasospasm (OR 0.96, 95% CI 0.95–0.98), and symptomatic vasospasm (OR 0.98, 95% CI 0.96–0.99).

Conclusions

Results in this study show that a younger age is associated with an increased incidence of angiographic and symptomatic vasospasm.

The superficial temporal artery trunk as a donor vessel in cerebral revascularization: benefits and pitfalls

Object

The superficial temporal artery (STA) is the mainstay of donor vessels for extracranial–intracranial bypass in cerebral revascularization. However, the typically used STA anterior or posterior branch is not always adequate in its flow-carrying capacity. In this report the authors describe the use of the STA trunk at the level of the zygoma as an alternative donor and highlight the benefits and pitfalls of this revascularization option.

Methods

The authors reviewed the cases of 4 patients in whom the STA trunk was used as a donor site for anastomosis of a short interposition vein graft. The graft was implanted into the middle cerebral artery to trap a cartoid aneurysm in 2 patients, and the posterior cerebral artery for vertebrobasilar insufficiency in the other 2. Discrepancies in size between the interposition vein and STA trunk were compensated for by a beveled end-to-end anastomosis or by implanting the STA trunk into the vein graft in an end-to-side fashion.

Results

Intraoperative flow measurements confirmed the significantly higher flow-carrying capacity of the STA trunk (54–100 ml/minute) compared with its branches (10–28 ml/minute). The STA trunk interposition graft has several advantages compared with an interposition graft to the cervical carotid, including a shorter graft and no need for a neck incision. However, in the setting of ruptured aneurysm trapping, with the risk of subsequent vasospasm, it is a poor conduit for endovascular therapies.

Conclusions

The STA trunk is a valuable donor option for cerebral revascularization, but should be avoided in the setting of subarachnoid hemorrhage.

What is the present pathogenetic concept of glaucomatous optic neuropathy?

Glaucomatous optic neuropathy implies loss of neural tissue, activation of glial cells, tissue remodeling, and change of blood flow. The blood flow reduction is not only secondary but has a primary component. Activation of astrocytes leads to an altered microenvironment. An unstable ocular perfusion, either due to IOP fluctuation or a disturbed autoregulation (due to primary vascular dysregulation syndrome) leads to a mild reperfusion injury. The superoxide (O(2)(-)) anion produced in the mitochondria of the axons, fuses with the nitric oxide (NO) diffusing from the astrocytes, leading to the damaging peroxynitrite (ONOO(-)). It is possible that the diffusion of endothelin and metalloproteinases to the surrounding of the optic nerve head leads to a local vasoconstriction and thereby increases the risk for venous occlusion and weakens the blood-brain barrier, which in extreme situations results in splinter hemorrhages. Activated retinal astrocytes can be visualized clinically. The involvement of primary vascular dysregulation in the pathogenesis of glaucomatous optic neuropathy may explain why women, as well as Japanese, suffer more often from normal-tension glaucoma.

What is the link between vascular dysregulation and glaucoma?

The need of blood flow to different organs varies rapidly over time which is why there is sophisticated local regulation of blood flow. The term dysregulation simply means that blood flow is not properly adapted to this need. Dysregulative mechanisms can lead to an over- or underperfusion. A steady overperfusion may be less critical for long-term damage. A constant underperfusion, however, can lead to some tissue atrophy or in extreme situations to infarction. Unstable perfusion (underperfusion followed by reperfusion) leads to oxidative stress. There are a number of causes that lead to local or systemic vascular dysregulation. Systemic dysregulation can be primary or secondary of nature. A secondary dysregulation is due to other autoimmune diseases such as rheumatoid arthritis, giant cell arteritis, systemic lupus erythematodes, multiple sclerosis, colitis ulcerosa, or Crohns disease. Patients with a secondary vascular dysregulation normally have a high level of circulating endothelin-1 (ET-1). This increased level of ET-1 leads to a reduction of blood flow both in the choroid and the optic nerve head but has little influence on autoregulation. In contrast, primary vascular dysregulation has little influence on baseline ocular blood flow but interferes with autoregulation. This, in turn, leads to unstable oxygen supply, which seems to be a relevant component in the pathogenesis of glaucomatous optic neuropathy.

Clinical review: Prevention and therapy of vasospasm in subarachnoid hemorrhage

Vasospasm is one of the leading causes of morbidity and mortality following aneurysmal subarachnoid hemorrhage (SAH). Radiographic vasospasm usually develops between 5 and 15 days after the initial hemorrhage, and is associated with clinically apparent delayed ischemic neurological deficits (DID) in one-third of patients. The pathophysiology of this reversible vasculopathy is not fully understood but appears to involve structural changes and biochemical alterations at the levels of the vascular endothelium and smooth muscle cells. Blood in the subarachnoid space is believed to trigger these changes. In addition, cerebral perfusion may be concurrently impaired by hypovolemia and impaired cerebral autoregulatory function. The combined effects of these processes can lead to reduction in cerebral blood flow so severe as to cause ischemia leading to infarction. Diagnosis is made by some combination of clinical, cerebral angiographic, and transcranial doppler ultrasonographic factors. Nimodipine, a calcium channel antagonist, is so far the only available therapy with proven benefit for reducing the impact of DID. Aggressive therapy combining hemodynamic augmentation, transluminal balloon angioplasty, and intra-arterial infusion of vasodilator drugs is, to varying degrees, usually implemented. A panoply of drugs, with different mechanisms of action, has been studied in SAH related vasospasm. Currently, the most promising are magnesium sulfate, 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, nitric oxide donors and endothelin-1 antagonists. This paper reviews established and emerging therapies for vasospasm.

Computed tomography grading schemes used to predict cerebral vasospasm after aneurysmal subarachnoid hemorrhage: a historical review

✓The elucidation of predictive factors of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is a major area of both clinical and basic science research. It is becoming clear that many factors contribute to this phenomenon. The most consistent predictor of vasospasm has been the amount of SAH seen on the postictal computed tomography scan. Over the last 30 years, it has become clear that the greater the amount of blood within the basal cisterns, the greater the risk of vasospasm. To evaluate this risk, various grading schemes have been proposed, from simple to elaborate, the most widely known being the Fisher scale. Most recently, volumetric quantification and clearance models have provided the most detailed analysis. Intraventricular hemorrhage, although not supported as strongly as cisternal SAH, has also been shown to be a risk factor for vasospasm.