Managing subarachnoid hemorrhage in the neurocritical care unit

Patients with aneurysmal subarachnoid hemorrhage who survive the initial hemorrhage require complex interventions to occlude the aneurysm, typically followed by a prolonged intensive care unit and hospital course to manage the complications that follow. Much of the morbidity and mortality from this disease happens in delayed fashion in the neurocritical care unit. Despite progress made in the last decades, much remains to be understood about this disease and how to best manage these patients. This article provides a review of current evidence and the authors' experience, aimed at providing practical aid to those caring for patients with this disease.

[Regional cerebral blood flow monitoring using thermal diffusion flowmetry. Description of 3 cases]

Cerebral blood flow is the most important physiologic parameter in the setting of brain injury. A regional measurement of the flow (rCBF), can be obtained using continuous methods such as thermal diffusion flowmetry (TD-rCBF). This technology of monitoring allows us to detect and quantify ischemic events related with the temporary artery clipping or malposition of the definitive clip and in patients who have suffered a subarachnoid hemorrhage (SAH) or a traumatic brain injury. Likewise, the precocious detection of ischemic events might help us to adopt more rapidly therapeutic measures and more efficienty. Three cases show during aneurysm clipping procedures and at intensive care: the effects of different hypnotics on TD-rCBF values; the relationship between TD-rCBF and somatosensory and motor evoked potentials; and changes in TD-rCBF and transcranial Doppler ultrasonography (TDU) during a vasospasm. TD-rCBF showed in real-time flow variations induced by anaesthetics and detected changes of CBF earlier than evoked potentials and TDU.

Brain tissue oxygen monitoring to assess reperfusion after intra-arterial treatment of aneurysmal subarachnoid hemorrhage-induced cerebral vasospasm: a retrospective study

BACKGROUND AND PURPOSE

Cerebral vasospasm resistant to medical management frequently requires intra-arterial spasmolysis. Angiographic resolution of vasospasm does not provide physiologic data on the adequacy of reperfusion. We recorded pre- and postspasmolysis PbO(2) data in the endovascular suite to determine whether this physiologic parameter could be used to determine when successful reperfusion was established.

MATERIALS AND METHODS

Eight patients with 10 Licox monitors and cerebral vasospasm underwent intra-arterial spasmolysis. Pre- and postspasmolytic PbO(2) was recorded for comparison. Other physiologic parameters, such as CPP, ICP, SaO(2), and Fio(2), were also recorded.

RESULTS

Mean prespasmolysis PbO(2) recordings were 35.2 and 27.3 for the mild-to-moderate and moderate-to-severe vasospasm group, respectively. Mean postspasmolysis PbO(2) increased to 40.3 and 38.4, respectively, which was statistically significant (P < .05) for both groups. In 100% of instances in the moderate-to-severe group and 83% of instances in mild-to-moderate group, the mean PbO(2) increased after spasmolysis and correlated with improvement in angiographic vasospasm. Other physiologic parameters, such as CPP, ICP, SaO(2), and Fio(2), did not show any statistically significant difference before and after spasmolysis.

CONCLUSIONS

PbO(2) monitoring provides the interventionalist with an objective physiologic parameter to determine adequate spasmolysis. Further investigation is needed to establish target PbO(2) rates indicative of adequate reperfusion, which can be used in the endovascular suite.

Proof of concept: endogenous antiangiogenic factors predict the occurrence of symptomatic vasospasm post subarachnoid hemorrhage

BACKGROUND

The pathogenesis of vasospasm (VS) post aneurysmal subarachnoid hemorrhage (SAH) is multifactorial and not completely understood. The authors hypothesize that circulating antiangiogenic factors play an important role in brain injury post SAH and that elevated levels predict the occurrence of symptomatic vasospasm.

METHODS

In this study the authors measured the serum and cerebrospinal fluid (CSF) levels of soluble endoglin (sEng) and soluble fms-like tyrosine kinase 1 (sFlt1) in controls and SAH patients within 48 h of the bleed. Patients were prospectively followed and subcategorized into those with (sVS) and without symptomatic vasospasm (no-sVS).

RESULTS

Compared to healthy controls, SAH patients had higher CSF levels of sEng (0.037 vs. 0.251 ng/ml; P = 0.02) and sFlt1 (0.068 vs. 0.679 ng/ml; P = 0.001). In the subgroup analysis, sVS patients had higher CSF levels of sEng and sFlt1 than no-sVS patients (sEng: 0.380 vs. 0.159 ng/ml, P = 0.02; sFlt1: 1.277 vs. 0.343 ng/ml, P = 0.01). The serum levels of sEng and sFlt1 were not statistically different among the different groups.

CONCLUSIONS

Based on these results the authors conclude that elevated CSF levels of sFlt1 and sEng herald the occurrence of symptomatic VS post SAH.

Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/american Stroke Association

PURPOSE

The aim of this guideline is to present current and comprehensive recommendations for the diagnosis and treatment of aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

A formal literature search of MEDLINE (November 1, 2006, through May 1, 2010) was performed. Data were synthesized with the use of evidence tables. Writing group members met by teleconference to discuss data-derived recommendations. The American Heart Association Stroke Council's Levels of Evidence grading algorithm was used to grade each recommendation. The guideline draft was reviewed by 7 expert peer reviewers and by the members of the Stroke Council Leadership and Manuscript Oversight Committees. It is intended that this guideline be fully updated every 3 years.

RESULTS

Evidence-based guidelines are presented for the care of patients presenting with aSAH. The focus of the guideline was subdivided into incidence, risk factors, prevention, natural history and outcome, diagnosis, prevention of rebleeding, surgical and endovascular repair of ruptured aneurysms, systems of care, anesthetic management during repair, management of vasospasm and delayed cerebral ischemia, management of hydrocephalus, management of seizures, and management of medical complications.

CONCLUSIONS

aSAH is a serious medical condition in which outcome can be dramatically impacted by early, aggressive, expert care. The guidelines offer a framework for goal-directed treatment of the patient with aSAH.

[Precursors of brain ischemia in patients in the acute stage of subarachnoid hemorrhage after the aneurysm rupture]

The authors attempted to predict an outcome of the disease using the dynamic evaluation of quantitative parameters of intracranial pressure (ICP) and linear systolic blood flow velocity (LSBFV). Seventeen patients, aged from 20 to 61 years, with acute subarachnoid hemorrhage (SAH) after the aneurysm rupture complicated with the syndrome of intracranial hypertension (SIH) and angiospasm were studied. A comparison of the clinical course and outcomes (good or bad) with corresponding quantitative parameters allows to conclude that the decrease in LSBFV (<200 cm/sec) in the syndrome of intracranial hypertension (ICP>30 mmHg) predicts the ischemic damage. LSBFV values higher than 200 cm/sec and ICP<30 mmHg reduces the risk for brain ischemia.

Recurring extracranial internal carotid artery vasospasm detected by intravascular ultrasound

A 24-year-old woman presented with headache and left-sided focal signs following multiple episodes of right monocular visual impairment. Magnetic resonance angiography revealed a decreased vascular image intensity due to a suspicious stenosis in the right internal carotid artery (ICA). The stenosis was not demonstrated on duplex sonography as it was beyond the field of view of the investigation. Intravascular ultrasound (IVUS) revealed that the outer vessel diameter was significantly reduced during stenosis, supporting the presence of vasospasm. Idiopathic recurrent extracranial ICA vasospasm was diagnosed. Recurrent vasospasms of extracranial ICA may be a distinct entity that can cause ischemic stroke.

[Case of postpartum intracerebral hemorrhage due to pregnancy induced hypertension]

A 32-year-old woman, gravida 0, para 0, was admitted to the obstetrics department of our hospital after a cesarean section at 35 weeks of gestation. The cesarean section was performed because pregnancy induced hypertension (PIH) had worsened. The next day, she suddenly became drowsy and developed right hemiparesis and anisocoria. Computed tomography of the brain showed intracerebral hemorrhage in the parietal lobe with uncal herniation. She underwent an urgent craniotomy and removal of the hematoma. Five days later, magnetic resonance angiography (MRA) of the brain showed vasospasm of the bilateral intracranial internal carotid arteries, middle cerebral arteries, and anterior cerebral arteries. Thirteen days later, cerebral angiography showed cessation of vasospasm and vascular abnormalities such as moyamoya disease, arteriovenous malformation and cerebral aneurysm were not observed. Twenty-one days later, MRA showed the absence of vasospasm in those arteries, but her right hemiparesis and sensory aphasia persisted. Twenty-six days later, she was transferred to another hospital for further rehabilitation. Neurosurgeons should be aware of the possibility of intracerebral hemorrhage caused by PIH. In this manuscript, we provide a case presentation and review of the literature.

[Progress in NIRS monitoring of cerebral blood flow]

Various studies have demonstrated the usefulness of near infrared spectroscopy (NIRS) for detecting cerebral ischemia during a carotid endarterectomy; however, it is difficult to apply NIRS to the diagnosis of ischemic stroke, since commercially available NIRS, which uses continuous-wave light, does not provide quantitative values of baseline hemoglobin (Hb) concentrations. In contrast, time-resolved near-infrared spectroscopy (TRS) permits quantitative measurement of Hb concentrations. We applied TRS to detection of cerebra vasospasm after subarachnoid hemorrhage (SAH). We investigated 11 age-matched controls and 14 aneurysmal SAH patients that comprised 10 patients with World Federation of Neurological Societies (WFNS) grade V and 4 patients with WFNS grade II. Employing TR-NIRS, we measured the cortical oxygen saturation (CoSO2) and baseline Hb concentrations in the middle cerebral artery territory. The CoSO2 and Hb concentrations remained stable after SAH in 6 patients; digital subtraction angiography (DSA) did not reveal vasospasm in these patients. In 8 patients, however, CoSO2 and total Hb decreased abruptly between 5 and 9 days after SAH. DSA revealed diffuse vasospasms in 6 of 8 patients. The reduction of CoSO2 predicted occurrence of vasospasm at a cutoff value of 3.9%-6.4% with 100% sensitivity and 85.7% specificity. Trans cranial Doppler (TCD) failed to detect vasospasm in 4 cases, whereas TR-NIRS could. Finally, TRS performed on day 1 after SAH revealed significantly higher CoSO2 than that of the controls (p = 0.048), but there was no significant difference in total Hb. TRS detected vasospasm by evaluating the CBO in the cortex and may be more sensitive than TCD, which assesses the blood flow velocity in the M1 portion. TRS may be useful for the diagnosis of ischemic events in stroke patients.

Role of endothelin-1 in human aneurysmal subarachnoid hemorrhage: associations with vasospasm and delayed cerebral ischemia

BACKGROUND

Endothelin-1 (ET-1) is a potent vasoconstrictor implicated in the pathogenesis of vasospasm and delayed cerebral ischemia (DCI) in aneurysmal subarachnoid hemorrhage (aSAH) patients. The aim of this study was to investigate the relationship between cerebrospinal fluid (CSF) ET-1 levels and angiographic vasospasm and DCI.

METHODS

Patients with aSAH were consented (n = 106). Cerebral vasospasm was determined by angiography. DCI was determined by transcranial Doppler (TCD) results and/or angiogram results with corresponding clinical deterioration. CSF ET-1 levels over 14 days after the initial insult was quantified by ELISA. ET-1 analysis included a group-based trajectory analysis and ET-1 exposure rate during 24, 48, and 72 h prior to, as well as 72 h post angiography, or clinical deterioration.

RESULTS

Trajectory analysis revealed two distinct groups of subjects with 56% of patients in the low ET-1 trajectory group (mean at day 1 = 0.31 pg/ml; SE = 0.04; mean at day 14 = 0.41 pg/ml; SE = 0.15) and 44% of patients in the high ET-1 trajectory group (mean at day 1 = 0.65 pg/ml; SE = 0.08; mean at day 14 = 0.61 pg/ml; SE = 0.06). Furthermore, we observed that ET-1 exposure rate 72 h before angiography and clinical spasm was a significant predictor of both angiographic vasospasm and DCI, whereas, ET-1 exposure after angiography and clinical spasm was not associated with either angiographic vasospasm or DCI.

CONCLUSION

Based on these results we conclude that ET-1 concentrations are elevated in a sub-group of patients and that the acute (72 h prior to angiography and clinical neurological deterioration), but not chronic, elevations in CSF ET-1 concentrations are indicative of the pathogenic alterations of vasospasm and DCI in aSAH patients.

Using continuous electroencephalography in the management of delayed cerebral ischemia following subarachnoid hemorrhage

BACKGROUND

Using clinical parameters to identify and monitor treatment response in patients with delayed cerebral ischemia (DCI) following subarachnoid hemorrhage is challenging. We sought to determine whether continuous electroencephalography (CEEG) aids the prediction of the clinical course and response to treatment of DCI.

METHODS

Patients deemed high-risk for DCI based on the modified Fisher scale were prospectively monitored. A novel CEEG parameter measuring relative alpha power and variability in the anterior brain quadrants termed composite alpha index (CAI) was graphically displayed. Predictions of the status of patients for the ensuing day were made by an independent reviewer, first using clinical data then repeated following the addition of CAI trends. These were compared to the actual clinical state. The reviewer was blinded to the presence and treatment of DCI. Patients with DCI were further studied by trending the daily mean alpha power against the modulation of treatment and clinical evolution.

RESULTS

Fifty-nine predictions were made in 12 patients (mean age 54.3 years, range 35-70; nine females) with Hunt-Hess grades ranging I-V. Sensitivity of predicting clinical deterioration with CEEG improved from 40 to 67% and clinical improvement from 8 to 50%. In three patients, CEEG was predictive greater than 24 h prior to clinical change. Tracking the daily mean alpha power accurately identified DCI recurrence and poor responders to first-line therapy at pre-clinical stages.

CONCLUSION

CEEG is a useful non-invasive tool to supplement routine clinical parameters in the prediction of DCI. It can dynamically monitor the response to treatment and might aid pre-clinical management decisions.

Ischaemic stroke after acute intracranial haemorrhage in patients with moyamoya disease: six new cases and a short literature review

BACKGROUND

We report six new cases of ischaemic stroke after cerebral haemorrhage in patients with moyamoya disease (MMD) and analyse their clinical and radiological characteristics, together with cases reported in the literature, to deduce the mechanism of cerebral infarct.

METHODS

Six (2%) of 246 patients with MMD who were admitted to our hospitals between 1993 and 2009 suffered cerebral infarct after intracranial haemorrhage. Ten patients identified in the literature with the PubMed search engine were also included in this study. All the ischaemic lesions in these 16 patients were analysed according to their location, size, and number and were compared according to the spatial relationship between the haemorrhage and infarct, as follows: (1) anterior vs posterior involvement, (2) cortical vs subcortical involvement, (3) watershed vs non-watershed infarct, (4) small vs large infarct, (5) single vs multiple infarct, and (6) adjacent vs distant involvement.

RESULTS

Acute synchronous multiple brain infarcts occurred in six (38%) patients and recurrent infarcts in three patients (19%). Cerebral infarcts had mainly cortical (72%), anterior (66%), and distant involvement (75%) and were large (69%) and non-watershed (66%). Adjacent infarct had significantly anterior involvement (P < 0.05), and distant infarcts tended to have cortical involvement. Non-watershed infarcts had significantly cortical involvement (P < 0.05). Watershed infarcts tended to be large. Vasospasm was confirmed either pathologically or angiographically in two patients with large cerebral infarcts.

CONCLUSIONS

We suggest that thromboembolism or vasospasm plays a crucial role in the pathogenesis of cerebral infarction after acute intracranial haemorrhage in patients with MMD.

Benign angiopathy of the central nervous system or reversible cerebral vasoconstriction syndrome

Benign angiopathy of the central nervous system is a subset of primary angiitis of the central nervous system characterized by "benign" course. It means that changes of cerebral vessels are reversible after treatment with corticosteroids and calcium channel blockers, so these abnormalities are believed to reflect vasospasm rather than true vasculitis. The diagnosis is made on the basis of clinical presentation, brain magnetic resonance imaging and cerebral angiography. We present a young man with acute onset of headache and neurologic impairment secondary to ischemic stroke with intracerebral and subarachnoid hemorrhage. Cerebral angiography showed characteristic findings of diffuse vasculitis but good response to treatment with corticosteroids and calcium channel blockers distinguish this benign angiopathy from the more aggressive form of the central nervous system vasculitis.

Current practices of triple-H prophylaxis and therapy in patients with subarachnoid hemorrhage

BACKGROUND

Medical management of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) includes hypertensive, hypervolemic, and hemodilution ("triple-H") therapy. However, there is little information regarding the indications and guidance used to initiate and adjust triple-H therapy.

METHODS

A 43-item questionnaire was e-mailed to 375 members of the Neurocritical Care Society. Questions were designed to investigate the diagnostic approach to cerebral vasospasm and prophylactic and therapeutic administration of triple-H therapy.

RESULTS

Completed surveys were received from 167 respondents (45% response proportion). Eighty-six percent of respondents worked in hospitals with neurointensive care units (NICUs). SAH patients in hospitals with a NICU had longer ICU stay (P = 0.037) and had indwelling central venous catheters for longer (P < 0.01). Centers without dedicated NICUs were more likely to induce prophylactic hypervolemia (P < 0.01). Twenty seven percent of respondents (n = 45) reported using prophylactic hypervolemia in patients with SAH, while 100% reported inducing hypervolemia for severe or symptomatic vasospasm. Twelve percent (n = 20) of respondents reported inducing prophylactic hypertension, while all reported inducing hypertension with severe or symptomatic vasospasm. Half of respondents relied on the mean arterial pressure and half on systolic blood pressure as the clinical parameter for blood pressure titration. The most widely used agents to induce hypertension were phenylephrine (48%) and norepinephrine (39%). There was little variation in the use of hemodilution therapy comparing patients with or without evidence of vasospasm.

CONCLUSIONS

There are substantial differences in the administration of prophylactic triple-H, but there was high agreement on indication for therapeutic use. There was wide variability in the extent of ICU monitoring, diagnostic approach, physiologic parameters and values used as target of therapy. NICU availability was associated with more intensive monitoring. Lack of evidence and guidelines for triple-H therapy might largely explain these findings.

[Symptomatic vasospasm. Clinical manifestations]

INTRODUCTION

Symptomatic vasospasm in the setting of a subarachnoid hemorrhage is a complication of difficult diagnosis in some clinical situations. Objectives. Describe the clinical characteristics of cerebral vasospasm demonstrated by neurovascular studies in patients with ruptured saccular aneurysm.

PATIENTS AND METHODS

19 consecutive patients with symptomatic vasospasm, evaluated with TCD and any variant of neurovascular study with contrast injection. All these cases were in degrees between 1 and 3 of the World Federation of Neurological Surgeons Scale.

RESULTS

The cognitive and behavioral manifestations were the most frequent (53%), followed by neurological focal deficits (26%). Clinical vasospasm occurred most frequently between day 9 and 10. Vasospasm is predominant in the arteries of the anterior circulation. The high mortality (42%) and the antecedent of arterial hypertension characterized the group with symptomatic vasospasm. There was no statistical relationship between the result of the scale of Fisher and the symptomatic vasospasm. All the TCD parameters had statistical significance.

CONCLUSIONS

The clinical manifestations more frequently associated with symptomatic vasospasm were cognitive and behavioral. This group of patients is characterized by a high mortality. The TCD is a test of great value to predict cerebral ischemia due to vasospasm.

Intracortical EEG for the detection of vasospasm in patients with poor-grade subarachnoid hemorrhage

BACKGROUND

To study the feasibility of utilizing intracortical electroencephalography (ICE) including quantitative EEG (qEEG) analysis for the detection of vasospasm in five consecutive poor-grade SAH patients.

METHODS

Intracortical electroencephalography (ICE) was obtained via a single miniature parenchymal 8-contact depth electrode placed at the bedside. Quantitative EEG parameters, calculated on surface EEG and ICE, included alpha/delta ratio (ADR), mean amplitude, suppression percent, and total power. Percent changes between averaged values over 4-6 h of baseline EEG and EEG prior to angiography were calculated. The entire continuous qEEG recording for each patient was then reviewed to determine optimal automated alarm criteria.

RESULTS

ICE ADR was the most accurate for predicting angiographic vasospasm (5/5). ICE ADR decreased between baseline and follow-up by 42% (from 0.56 ± 0.07 to 0.32 ± 0.03) for those with vasospasm (N = 3) compared to 17% (0.62 ± 0.06 to 0.51 ± 0.03) for those without (N = 2). A sustained decrease in the ICE ADR from baseline (>25% for ≥ 4 h) occurred in all three patients with angiographically confirmed vasospasm and not in the two without; this decline occurred 1-3 days prior to angiographic confirmation.

CONCLUSIONS

Intracortical EEG is promising for detecting ischemia from vasospasm in poor-grade SAH patients, may be superior to scalp EEG, and allow automated detection, particularly using the ADR. Larger studies are needed to better define the effectiveness of this approach.

Continuous cardiac output and near-infrared spectroscopy monitoring to assist in management of symptomatic cerebral vasospasm after subarachnoid hemorrhage

BACKGROUND

Hemodynamic augmentation by increasing cardiac output with dobutamine (DOB) is believed to be a useful method of elevating decreased cerebral blood flow in the territory affected by vasospasm following aneurysmal subarachnoid hemorrhage (SAH). We described the clinical utility of uncalibrated radial artery-based pulse contour cardiac output (APCO) and near-infrared spectroscopy regional cerebral oxygen saturation (rSO(2)) monitoring for reversing vasospasm symptoms with DOB-induced hyperdynamic therapy.

METHODS

Seven consecutive patients who underwent surgical clipping within 24 h of SAH onset and subsequently developed delayed ischemic neurological deficits attributable to vasospasm were investigated. They were treated with DOB administered at a dose of 3 μg/kg/min and then increased in 3 μg/kg/min increments until resolution of the symptoms. Continuous APCO and rSO(2) measurements in conjunction with the assessment of clinical courses and outcomes were performed.

RESULTS

In spasm-affected territories, decreased and/or fluctuating rSO(2) was detected at baseline compared with recordings in other brain regions. Patients who exhibited rapid elevation of APCO in response to an incremental dose of DOB had subsequent uptake and stabilization of rSO(2) followed by improvement of vasospasm-related clinical symptoms with a maximal dose of DOB, resulted in favorable functional outcomes thereafter. A fairly strong relationship was found between peak APCO slope and rSO(2) elevation, with a significantly high area under the receiver operating characteristic curve predicting neurological improvement with DOB treatment.

CONCLUSIONS

Our clinical experience indicates that integrative monitoring with APCO and rSO(2) may provide continuous, real-time, and clinically relevant information on the effectiveness of medical treatment of distal vessel vasospasm.

Hypoperfusion in the acute phase of subarachnoid hemorrhage

PURPOSE

Acute disruption of cerebral perfusion and metabolism is a well-established hallmark of the immediate phase after subarachnoid hemorrhage (SAH). It is thought to contribute significantly to acute brain injury, but despite its prognostic importance, the exact mechanism and time course is largely unknown and remains to be characterized.

METHODS

We investigated changes in cerebral perfusion after SAH in both an experimental and clinical setting. Using an animal model of massive, experimental SAH (n=91), we employed Laser-Doppler flowmetry (LDF), parenchymal microdialysis (MD; n=61), Diffusion-weighted imaging (DWI) and MR spectroscopy (MRS; n=30) to characterize the first hours after SAH in greater detail. The effect of prophylactic treatment with hypothermia (HT; 32°C) and an endothelin-A (ET-A) receptor antagonist (Clazosentan) was also studied. In a group of patients presenting with acute SAH (n=17) we were able to determine cerebral blood flow (CBF) via Xenon-enhanced computed tomography (XeCT) within 12 h after the ictus.

RESULTS

The acute phase after SAH is characterized both experimentally and clinically by profound and prolonged hypoperfusion independent from current intracranial pressure (ICP), indicating acute vasospasm. Experimentally, when treated with hypothermia or a ET-A receptor antagonist prophylactically, acute hypoperfusion improved rapidly. DWI showed a generalized, significant decline of the apparent diffusion coefficient (ADC) after SAH, indicating cytotoxic edema which was not present under hypothermia. SAH causes a highly significant reduction in glucose, as well as accumulation of lactate, glutmate and aspartate (MD and MRS). HT significantly ameliorated these metabolic disturbances.

CONCLUSION

Acute vasospasm, cytotoxic edema and a general metabolic stress response occur immediately after experimental SAH. Prophylactic treatment with hypothermia or ET-A antagonists can correct these disturbances in the experimental setting. Clinically, prolonged and ICP-independent hypoperfusion was also confirmed. As the initial phase is of particular importance regarding the neurological outcome and is amenable to beneficial intervention, the acute stage after SAH demands further investigation and warrants the exploration of measures to improve the immediate management of SAH patients.

A numerical approach to patient-specific cerebral vasospasm research

BACKGROUND

cerebral vasospasm (CVS) is a devastating sequela of subarachnoid hemorrhage (SAH). Among the many factors that are associated with the pathogenesis of CVS, the cerebral blood flow (CBF) and underlying haemodynamics play an important role. In this paper we present an integrated clinical-engineering approach to CVS research.

METHOD

after an admission CT scan, CT angiography (CTA) and/or Digital Subtraction Angiography (DSA) scans are performed for SAH patients. The anatomy of cerebral vasculature and its geometric parameters are monitored and compared with follow-up CTA and/or DSA scans. The governing equations for blood flow are numerically solved for the arteries and the computational results are analysed.

FINDINGS

in the particular CVS case presented in this paper, the numerical results indicate that blood flow velocity increases in moderate and severely spastic vessels (A1, M1 segment) that perfuse brain tissues. However, decreased vessel diameters in A1 and M1 arteries create larger resistance to CBF and hence lead to reduced flow in the inner carotid artery (ICA).

CONCLUSIONS

a numerical approach to patient-specific CVS analysis has been established, and some initial results are achieved via application to an actual spasm case. The undergoing and future work include applying the approach to more CVS cases and incorporating computational models of different scales into the current framework for CVS and SAH research.

Nicardipine pellets for the prevention of cerebral vasospasm

Regardless of numerous efforts there is no prophylactic treatment proven to be effective in the prevention of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH). As systemic administration of vasoactive drugs has been associated with significant side effects and insufficient efficacy, intrathecal administration of nicardipine prolonged-release implants (NPRI) has been developed. At the time of surgical clipping of the ruptured aneurysm, NPRIs are positioned next to the large cerebral arteries. Several clinical protocols revealed that NPRIs dramatically reduce the incidence and severity of angiographic vasospasm, which was paralled by a reduction in cerebral infarction and delayed ischemic neurologic deficit. On average, the incidence of angiographic vasospasm decreased from approximately 70% to less than 10%. Efficacy seemed to be dose-dependent and reduced for peripheral vasospasm. Nevertheless, a significant improvement of functional outcome was demonstrated. A separate patient series demonstrated the efficacy of fewer NPRIs in the perichiasmatic cistern. Further investigations were performed in comparison to coiled patients and with intraventricular implantation of NPRIs, which had a less pronounced effect. Overall, NPRIs are a most promising option for the prevention of cerebral vasospasm after SAH and large controlled trials are needed to further confirm these results.

The correlation between COMT gene polymorphism and early cerebral vasospasm after subarachnoid hemorrhage

BACKGROUND

The individual difference of cerebral vasospasm (CVS) degree after subarachnoid hemorrhage (SAH) is common in clinic observation. Numerous studies have found that early CVS after SAH is associated with derangements in catecholamine (CA) metabolism. Catechol-O-methyltransferase (COMT) is a key rate-limiting enzyme in the degradation of CA. In this study, we investigate the correlation between COMT gene polymorphism of patients and early CVS after SAH.

METHODS

One hundred and sixty-seven patients with spontaneous SAH in early stage were selected in this study. COMT genotyping was performed by means of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The degree of CVS was identified by TCD. Hunt-Hess classification was used to evaluate the severity of the patients' condition. The bleeding amount was evaluated by means of Fisher classification of head CT. χ2 test (SPSS13.0 software) and logistic regression were adopted to analyze the correlation of COMT gene polymorphism and other clinical data of patients with early CVS after SAH.

RESULTS

The distribution of each allele matched Hardy-Weinberg law and research samples were heredity equilibrium population. Early CVS incidence of patients with COMT-A allele was much higher than those with COMT-G allele (P<0.01). Early CVS incidence of patients with COMT A/A genotype was obviously higher than those with COMT G/G genotype (P<0.05). Univariate logistic regression demonstrated that COMT-A allele, A/A genotype and Grade 3-5 of Hunt-Hess classification were all associated with early CVS. After adjustment of general information, further multivariate logistic regression demonstrated that COMT-A allele, A/A genotype were risk factors of early CVS after SAH.

CONCLUSION

COMT-A allele, A/A genotype were risk factors of early CVS after SAH.