Comparison of transcranial Doppler investigation of aneurysmal vasospasm with digital subtraction angiographic and clinical findings

Transcranial Doppler Velocities and Angiographic Vasospasm after SAH: A Diagnostic Accuracy Study

BACKGROUND AND PURPOSE

After aneurysmal SAH, transcranial Doppler is commonly used to monitor cerebral vasospasm. The diagnostic accuracy of transcranial Doppler flow velocity values in detecting angiographic vasospasm in patients requiring urgent endovascular intervention has not been established.

MATERIALS AND METHODS

We performed a retrospective analysis of a consecutive series of patients with aneurysmal SAH who underwent transcranial Doppler (index test) within 24 hours of conventional angiography (reference test). The judgment of 33%, 50%, and 66% degree of vessel narrowing on angiography was independently established by multiple neuroendovascular clinicians. Vessel-specific per-segment and per-patient transcranial Doppler velocities were studied using receiver operating characteristic curves, the Youden index, and minimal acceptable sensitivity models. Optimal mean flow-velocity thresholds were explored to calculate sensitivity and specificity using a per-patient judgment of vasospasm of at least 50% angiographic narrowing in any large arterial segment except A1.

RESULTS

In 221 patients, vasospasm was found in 15%, 8%, and 4% of arteries when the degree of reference angiographic luminal narrowing was 33%, 50%, and 66%, respectively. Mean flow velocities were significantly higher in vasospastic segments (P = . 001), but per-segment exploratory analyses yielded unsound mean flow velocity thresholds. The Youden and minimal acceptable sensitivity models proposed mean flow velocity thresholds of approximately 160 cm/s for the anterior circulation and 80 cm/s for the posterior circulation in the per-patient diagnosis of angiographic vasospasm (≥50%), yielding a sensitivity of 80%-90% (95% CI, 0.77-0.96), but with a corresponding specificity of 50% (95% CI, 0.40-0.56).

CONCLUSIONS

In this study, a threshold transcranial Doppler mean flow-velocity value that would accurately diagnose ≥50% angiographic vasospasm remained elusive.

Evaluation of the Accuracy in Maximum Intensity Projection Images of Cerebral Computed Tomographic Angiography for the Diagnosis of Cerebral Vasospasm Following Subarachnoid Hemorrhage, in Comparison to Digital Subtraction Angiography

Objective

The purpose of this retrospective study is to determine the accuracy of maximum intensity projection (MIP) images of computed tomographic angiography (CTA) for diagnosis of cerebral vasospasm (CV) following subarachnoid hemorrhage (SAH) compared with that of digital subtraction angiography (DSA).

Materials and Methods

For patients admitted to our hospital for SAH, MIP images of CTA and DSA were checked at admission, and images were taken again 1 week later. This protocol was used in 39 cases. MIP images of CTA and DSA examinations were reviewed by two independent readers.

Results

Accuracy of MIP images of CTA in various arterial segments, using DSA as the gold standard: the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for different segments varied from 84 to 97, 33–100, 84–100%, 25–85, and 79–97%, respectively, for readers. Accuracy of CTA in various vasospasm severity, using DSA as the gold standard: the sensitivity, specificity, PPV, NPV, and accuracy for different vasospasm severity varied from 44 to 100, 69–100, 36–100%, 61–100, and 88–100%, respectively, for readers. Accuracy of CTA in central segments versus peripheral segments, using DSA as the gold standard: the sensitivity, specificity, PPV, NPV, and accuracy for central segments and peripheral segments varied from 90 to 94, 68–83, 93–97%, 56–69, and 87–93%, respectively, for readers.

Conclusion

MIP imaging of CTA is a useful modality when diagnosing CV after SAH.

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.

Angiographic circulation time and cerebral blood flow during balloon test occlusion of the internal carotid artery

Angiography-based balloon test occlusion (BTO) has been empirically used to predict tolerance to permanent carotid artery occlusion. We tested the hypothesis that the laterality of the hemispheric circulation time (HCT) of the contrast medium at cerebral angiography would reflect bilateral asymmetry of the cerebral blood flow (CBF) during BTO. Thirty-one consecutive patients who underwent BTO of the internal carotid artery were retrospectively analyzed. HCT was defined as the interval between the time-to-peak in the middle cerebral artery and the cortical veins calculated using time-density curve. The difference in HCT between the occluded and nonoccluded side was calculated at the carotid or dominant vertebral angiograms obtained during BTO. We estimated the correlation between the difference in HCT and bilateral asymmetry of the CBF, which was quantitatively determined by single-photon emission computed tomography. The HCT was 5.3±1.5 seconds and regional CBF was 41.3±11.3 mL/100 g per minute in the occluded side, compared with 3.6±0.9 seconds and 48.4±14.9 mL/100 g per minute in the nonoccluded side, respectively. The difference in HCT was strongly correlated with the asymmetry ratio of the CBF (r(2)=0.89, P<0.0001). Angiographically based measurement of the cerebral circulation time can provide valuable information concerning cerebral hemodynamics.

Inflammation, cerebral vasospasm, and evolving theories of delayed cerebral ischemia

Cerebral vasospasm (CVS) is a potentially lethal complication of aneurysmal subarachnoid hemorrhage (aSAH). Recently, the symptomatic presentation of CVS has been termed delayed cerebral ischemia (DCI), occurring as early as 3-4 days after the sentinel bleed. For the past 5-6 decades, scientific research has promulgated the theory that cerebral vasospasm plays a primary role in the pathology of DCI and subsequently delayed ischemic neurological decline (DIND). Approximately 70% of patients develop CVS after aSAH with 50% long-term morbidity rates. The exact etiology of CVS is unknown; however, a well-described theory involves an antecedent inflammatory cascade with alterations of intracellular calcium dynamics and nitric oxide fluxes, though the intricacies of this inflammatory theory are currently unknown. Consequently, there have been few advances in the clinical treatment of this patient cohort, and morbidity remains high. Identification of intermediaries in the inflammatory cascade can provide insight into newer clinical interventions in the prevention and management of cerebral vasospasm and will hopefully prevent neurological decline. In this review, we discuss current theories implicating the inflammatory cascade in the development of CVS and potential treatment targets.

Vasospasm after SAH due to aneurysm rupture of the anterior circle of Willis: value of TCD monitoring

OBJECTIVE

The aim of this study was to verify the presence of angiographic vasospasm in patients with transcranial Doppler (TCD) of high velocities after subarachnoid hemorrhage (SAH).

METHODS

Seven hundred and eighty-six cases admitted within 48 hours after SAH due to the rupture of anterior circulation aneurysm, were prospectively studied with TCD. In cases of TCD velocities higher than 120 cm/s (TCD vasospasm), the patient underwent a control angiography. Hunt-Hess and Fisher's grade on admission CT and location of the aneurysm were related to occurrence of TCD vasospasm. The increase in TCD velocities within 24 hours was calculated and related to the presence of cerebral ischemia on discharge CT, considering three groups of patients: Group A with an increase in velocities higher than 60%, Group B with an increase in velocities between 30 and 60%, and Group C with an increase in velocities lower than 30%.

RESULTS

TCD vasospasm was observed in 216 patients (27%). In 97% of patients with TCD vasospasm on middle cerebral artery (MCA) and in 71% with TCD vasospasm on anterior cerebral artery (ACA), control angiography confirmed the vasospasm, with a significant lower diagnostic TCD predictivity of ACA spasm (chi2=28.204, p=0.000). The overall positive predictive value of TCD was 89%. There was no significant correlation of TCD vasospasm with clinical status on admission and location of the aneurysm, but a significant correlation between occurrence of TCD vasospasm and Fisher's grade (chi2=15.470, p=0.002) and between the increase rate in TCD velocities and cerebral ischemia (chi2=56.564, p=0.000).

CONCLUSION

Our study shows a good correlation between TCD and angiography to detect vasospasm on MCA, but the correlation is low for ACA. TCD alone cannot discriminate different hemodynamic pathways after SAH.

Current advances in the diagnosis of vasospasm

Symptomatic vasospasm leading to delayed ischemia and neurological deficits is one of the most serious complications after aneurysmal subarachnoid hemorrhage (SAH). Reliable and early detection of symptomatic vasospasm is one of the major goals in the management of patients with SAH. In awake patients, the close clinical neurological examination still remains the most important diagnostic measure. In comatous or sedated patients, cerebral angiography remains the mainstay of the diagnostic workup for vasospasm. However, angiography does not allow assessing the hemodynamic relevance of vasospasm and is not suited for early identification of cerebral hypoperfusion and ischemia. Therefore, a large panel of new monitoring techniques for the assessment of regional cerebral perfusion has been recently introduced into the clinical management of SAH patients. This article briefly reviews the most relevant methods for monitoring cerebral perfusion and discusses their clinical predictive value for the diagnosis of vasospasm. On the basis of the currently available monitoring technologies, an algorithm for the diagnosis of vasospasm is presented.

Advanced imaging modalities in the detection of cerebral vasospasm

The pathophysiology of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is complex and is not entirely understood. Mechanistic insights have been gained through advances in the capabilities of diagnostic imaging. Core techniques have focused on the assessment of vessel caliber, tissue metabolism, and/or regional perfusion parameters. Advances in imaging have provided clinicians with a multifaceted approach to assist in the detection of cerebral vasospasm and the diagnosis of delayed ischemic neurologic deficits (DIND). However, a single test or algorithm with broad efficacy remains elusive. This paper examines both anatomical and physiological imaging modalities applicable to post-SAH vasospasm and offers a historical background. We consider cerebral blood flow velocities measured by Transcranial Doppler Ultrasonography (TCD). Structural imaging techniques, including catheter-based Digital Subtraction Angiography (DSA), CT Angiography (CTA), and MR Angiography (MRA), are reviewed. We examine physiologic assessment by PET, HMPAO SPECT, ¹³³Xe Clearance, Xenon-Enhanced CT (Xe/CT), Perfusion CT (PCT), and Diffusion-Weighted/MR Perfusion Imaging. Comparative advantages and limitations are discussed.

Relative changes in transcranial Doppler velocities are inferior to absolute thresholds in prediction of symptomatic vasospasm after subarachnoid hemorrhage

The absolute transcranial Doppler (TCD) velocity threshold has been validated as a screening tool for vasospasm after subarchnoid hemorrhage (SAH). We assessed whether relative changes in velocity were superior to absolute TCD thresholds in the detection of symptomatic vasospasm. We reviewed consecutive patients with aneurysmal SAH who underwent serial TCD monitoring and survived at least 7 days. We recorded initial flow velocity (IFV) and maximal flow velocity (MFV) of the middle cerebral artery (MCA) serially up to 14 days from admission. We calculated relative flow velocity changes (MFV/IFV) and maximum change in mean flow velocity (FVmean) over any consecutive 2 days in addition to standard absolute measures of Lindegaard ratio (LR) and FVmean. We calculated receiver operating characteristic curve and area under curve (AUC) values, sensitivity, specificity, and positive predictive and negative predictive values for these parameters, optimal cutpoints, and various combinations. Forty-eight of 211 patients (23%) developed symptomatic MCA vasospasm. AUC values for various TCD parameters were 0.80 for MCA MFV >175 cm/s, 0.71 for LR >6, 0.64 for MFV/IFV >2, and 0.64 for >70% change in MFV over 2 days. The best characteristics were observed for the combination of MFV >175 cm/s and/or maximal LR >6 (AUC 0.81). Our data suggest that absolute thresholds of TCD FVmean provide the most accurate prediction of symptomatic MCA vasospasm after SAH. Other thresholds, including relative change from baseline and day-to-day changes, are inferior to established absolute thresholds.

An automated algorithm to improve the precision of basilar artery diameter measurements before and after subarachnoid hemorrhage-induced vasospasm in an animal model

OBJECTIVE

Quantifying vasospasm has traditionally been performed manually, a method prone to imprecision and user bias. An alternative approach is to use computerized image analysis techniques to define and quantify the diameter of a vessel. The goal of this article is to demonstrate a novel automated vessel measurement algorithm specific to the needs of vasospasm studies and to compare it with traditional manual measurements in an animal model of vasospasm.

METHODS

A total of 576 arterial diameter measurements were collected by 4 independent, blinded examiners from 24 angiograms in a rabbit subarachnoid hemorrhage (SAH) model. Measurements were taken from 3 segments of the basilar artery in anteroposterior and lateral projections, both before SAH and after SAH-induced vasospasm. Means and standard deviations of 288 manual measurements were compared with 288 automated measurements.

RESULTS

The precision of automated measurements was significantly improved compared with standardized manual measurements (85.7% decrease in variation; P < .001). When using automated measurements, the precision was not affected by vessel size, but when using manual measurements, smaller arteries were less precise (P = .04). There was no significant difference in precision between 2 different contrast concentrations (P = .32).

CONCLUSION

Automated measurements of basilar artery diameters are more precise than manual measurements, both before and after SAH-induced vasospasm. The variability in the manual group worsens when the artery is smaller secondary to vasospasm, indicating a need for the use of this segmentation method.

Controversies in neurosciences critical care

Perhaps the greatest recent controversy in the medical management of complex neurologic and neurosurgical patients has been the defining of the optimal care arena. Despite some early skepticism and measured recognition by the ICU community, neurosciences critical care has grown into a well-recognized subspecialty. Within this environment, the diverse expertise of surgeons, neurologists, and anesthesiologists come together to define best therapeutic strategies. Two neurologic disease states that, in particular, continue to elicit expansive interdisciplinary debate are spontaneous intracerebral hemorrhage and aneurysmal subarachnoid hemorrhage.

Endothelial nitric oxide synthase polymorphism (-786T->C) and increased risk of angiographic vasospasm after aneurysmal subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Vasospasm after aneurysmal subarachnoid hemorrhage (SAH) remains a leading cause of death and disability after aneurysm rupture. Decreased availability of nitric oxide (NO) may be crucial in its pathogenesis. We hypothesized that endothelial NO synthase (eNOS) polymorphisms may determine susceptibility to vasospasm in SAH patients.

METHODS

We conducted a prospective cohort study of SAH patients and determined vasospasm by cerebral angiography. We genotyped 3 eNOS polymorphisms: an intron 4 variable-number tandem-repeat, a promoter single-nucleotide polymorphism (-786T-->C SNP), and a coding SNP in exon 7 (894G-->T encoding E298D). Using multivariable logistic regression, we quantified the association of eNOS polymorphisms in patients with vasospasm confirmed by cerebral angiography.

RESULTS

For the eNOS promoter -786T-->C SNP, the presence of the CC genotype compared with any T genotype (CT or TT) was associated with increased odds of vasospasm (odds ratio=2.97, 95% CI=1.32 to 6.67, P=0.008). No association with vasospasm was observed for the eNOS 894G-->T or variable-number tandem-repeat polymorphisms.

CONCLUSIONS

These findings suggest that genetic variation influencing NO regulation contributes to the risk of angiographic vasospasm in patients with SAH. The specific role of the promoter SNP (-786T-->C) may determine the effect of NO regulated by this pathway, distinct from other known eNOS polymorphisms.

Vasospasm probability index: a combination of transcranial doppler velocities, cerebral blood flow, and clinical risk factors to predict cerebral vasospasm after aneurysmal subarachnoid hemorrhage

OBJECT

The goal in this study was to create an index (vasospasm probability index [VPI]) to improve diagnostic accuracy for vasospasm after subarachnoid hemorrhage (SAH).

METHODS

Seven hundred ninety-five patients in whom aneurysmal SAH was demonstrated by computed tomography, and in whom one or more intracranial aneurysms had been diagnosed, underwent transcranial Doppler (TCD) studies between April 1998 and January 2000. In 154 patients angiography was performed within 24 hours of the TCD examination, and in 75 133Xe cerebral blood flow (CBF) studies were obtained the same day. Seven cases were excluded because of a limited sonographic window. Forty-one women (60.3%) and 27 men (39.7%) between the ages of 35 and 84 years (58.0 +/- 13.2 years [mean +/- standard deviation]) were included. Clinical characteristics analyzed included age, sex, Hunt and Hess grade, Fisher grade, days after SAH, day of treatment, type of treatment (coil embolization, surgical clip occlusion, or conservative treatment), smoking history, and hypertension history. Lindegaard ratios and spasm indexes (TCD velocities/hemispheric CBF) were calculated bilaterally. Digital subtraction angiography images were measured at specific points of interest. Sensitivity, specificity, predictive values, and global accuracy of the different tests were calculated. Logistic regression was used to evaluate the possible predictive factors, and the coefficients of the logistic regression were integrated to create the VPI.

RESULTS

In 18 patients (26.5%) symptomatic vasospasm was diagnosed, and 33 (48.5%) had angiographic evidence of vasospasm. For TCD velocities above 120 cm/second at the middle cerebral artery, the global accuracy was 81.1% for the diagnosis of clinical vasospasm and 77.2% for angiographic vasospasm. For a Lindegaard ratio higher than 3.0, the accuracy was 85% for clinical vasospasm and 83.2% for angiographic vasospasm. A spasm index higher than 3.5 had an accuracy of 82.0% for the diagnosis of clinical vasospasm and 81.6% for angiographic vasospasm. The selected model for estimation of clinical vasospasm included Fisher grade, Hunt and Hess grade, and spasm index. The VPI had a global accuracy of 92.9% for clinical vasospasm detection. For diagnosis of angiographic vasospasm, the model included Fisher grade, Hunt and Hess grade, and Lindegaard ratio. The VPI achieved a global accuracy of 89.9% for angiographic vasospasm detection.

CONCLUSIONS

The use of TCD velocities, Lindegaard ratio, and spasm index independently is of limited value for the diagnosis of clinical and angiographic vasospasm. The combination of predictive factors associated with the development of vasospasm in the new index reported here has a significantly superior accuracy compared with the independent tests and may become a valuable tool for the clinician to evaluate the individual probability of cerebral vasospasm after aneurysmal SAH.

Predictors of 1-year outcome after coiling for poor-grade subarachnoid aneurysmal hemorrhage

OBJECTIVE

To describe features in patients admitted to the intensive care unit (ICU) for poor-grade aneurysmal subarachnoid hemorrhage (SAH) and to identify predictors of 12-month outcome.

METHODS

We conducted a controlled observational study of 51 consecutive patients treated with endovascular coiling within 96 h of rupture for poor-grade aneurysmal SAH (20 men and 31 women, age 54 +/- 12 years). We recorded co-morbidities; initial severity; aneurysm location; occurrence of acute hydrocephalus, initial seizures, and/or neurogenic lung edema; troponin values, Fisher grade; computed tomography (CT) findings; treatment intensity; and occurrence of vasospasm. The brain injury marker S100B was assayed daily over the first 8 days. Glasgow Outcome Scores (GOS) were recorded at ICU discharge, at 6 and 12 months. The main outcome criterion was the 1-year GOS score, which we used to classify patients as having a poor outcome (GOS 1-3) or a good outcome (GOS 4-5).

RESULTS

Overall, clinical status after 1 year was very good (GOS 5) in 41% of patients and good (GOS 4) in 16%. Neither baseline characteristics nor interventions differed significantly between patients with good outcome (GOS 4-5) and those with poor outcome (GOS 1-3). Persistent intracranial pressure elevation and higher mean 8-day S100B value significantly and independently predicted the 1-year GOS outcome (P = 0.008 and P = 0.001, respectively).

CONCLUSIONS

Patients in poor clinical condition after SAH have more than a 50:50 chance of a favorable outcome after 1 year. High mean 8-day S100B value and persistent intracranial hypertension predict a poor outcome (GOS 1-3) after 1 year.

Transcranial Doppler monitoring and clinical decision-making after subarachnoid hemorrhage

Our objective was to examine the impact of transcranial Doppler ultrasound (TCD) vasospasm monitoring on clinical decision-making following subarachnoid hemorrhage (SAH). The records of 50 randomly selected patients undergoing serial TCD monitoring following SAH were reviewed. Dates and results of TCDs and cerebral angiograms, the use of hypertensive hemodilution (HH) therapy, and the development of new neurological deficits were recorded. The independent effects of TCD-defined vasospasm and new neurological deficits on patient management were determined with multiple logistical regression. Results were validated in a second randomly selected, 50 patient cohort. Mild or moderate TCD-defined vasospasm developed in 76% of patients 5.8 +/- 0.5 days after SAH; 38% developed severe TCD-defined vasospasm after 7.9 +/- 0.7 days. Focal neurological deficits occurred in 50% after 5.7 +/- 0.6 days with TCD abnormalities preceding the deficit by 2.5 +/- 0.7 days in 64%. TCD-defined vasospasm or a new neurological deficit explained 60% of the variance in the use of HH therapy (P = .005). New neurological deficits increased the odds of HH therapy 33-fold (P = .004) whereas there was no independent effect of TCD-defined vasospasm. These variables explained 64% of the variance in the performance of angiography (P = .0002). An abnormal TCD did not increase the odds of angiography whereas its use increased 28-fold (P = .01) after a neurological deficit developed. These results were confirmed in an independent cohort. We concluded that TCD-defined vasospasm did not independently influence the use of HH therapy or angiography with both decisions associated with the development of new neurological deficits. As TCD-defined vasospasm preceded the neurological deficit in 64%, earlier intervention might reduce the incidence of vasospasm-related stroke in institutions with similar practice patterns.

New developments in cerebral monitoring

In past years, cerebral monitoring was mostly focused around global cerebral perfusion and metabolism monitoring, with the use of transcranial Doppler recordings, jugular bulb oximetry and near-infrared spectroscopy. Most of the recently introduced cerebral monitoring modalities, such as brain tissue partial oxygen tension monitoring and cerebral microdialysis, offer new opportunities by providing regional information on the specific brain area in which the probe is inserted. Ideally, these probes should be inserted in that area of the brain that is most vulnerable to ischaemia, but that may be salvageable with appropriate therapy. In this case, the combination of global and regional cerebral monitoring might offer the best information on which to base patient management. Also, the introduction of more clinically useful, functional neuroimaging techniques may be a valuable adjunct to future neurological critical care management.

Management of 350 aneurysmal subarachnoid hemorrhages in 22 Italian neurosurgical centers

OBJECTIVE

To collect information on clinical practice and current management strategies in 22 Italian neurosurgical hospitals for patients with aneurysmal subarachnoid hemorrhage.

DESIGN AND SETTING

Observational 6-month study for prospective data collection.

PATIENTS

350 cases of aneurysmal subarachnoid hemorrhage.

MEASUREMENTS AND RESULTS

Each center enrolled from 4-36 patients. Neurological deterioration (24%) was more frequent in patients with higher Fisher classification, and with pretreatment rebleeding and it was associated with an unfavorable outcome (46%, 36/78, vs. 33%, 83/251). Aneurysms were mainly secured by clipping (55%, 191/350). An endovascular approach was utilized in 35% (121/350). The more frequent medical complications were fever, recorded in one-half of cases, pneumonia (18%), sodium disturbances (hyponatremia 22%, hypernatremia 17%), cardiopulmonary events as neurogenic pulmonary edema (4%) and myocardial ischemia (5%). Intracranial hypertension was experienced in one-third of the patients, followed by hydrocephalus (29%) and vasospasm (30%). Cerebral ischemia was found in an about one-quarter of the cohort. To identify the independent predictors of outcome we developed a model in which the dichotomized Glasgow Outcome Scale was tested as function of extracranial and intracranial complications. Only high intracranial pressure and deterioration in neurological status were independent factors related to unfavorable outcome.

CONCLUSIONS

Our data confirm that in every step of care there is extreme heterogeneity among centers. These patients are complex, with comorbidities, immediate risk of rebleeding, and delayed risk of intracranial and medical complications. Following SAH early treatment and careful intensive care management requires the careful coordination of the various clinical specialties.

Intravenous magnesium versus nimodipine in the treatment of patients with aneurysmal subarachnoid hemorrhage: a randomized study

OBJECTIVE

The prophylactic use of nimodipine in patients with aneurysmal subarachnoid hemorrhage reduces the risk of ischemic brain damage. However, its efficacy seems to be rather moderate. The question arises whether other types of calcium antagonists offer better protection. Magnesium, nature's physiological calcium antagonist, is neuroprotective in animal models, promotes dilatation of cerebral arteries, and has an established safety profile. The aim of the current pilot study is to evaluate the efficacy of magnesium versus nimodipine to prevent delayed ischemic deficits after aneurysmal subarachnoid hemorrhage.

METHODS

One hundred and thirteen patients with aneurysmal subarachnoid hemorrhage were enrolled in the study and were randomized to receive either magnesium sulfate (loading 10 mg/kg followed by 30 mg/kg daily) or nimodipine (48 mg/d) intravenously until at least postoperative Day 7. Primary outcome parameters were incidence of clinical vasospasm and infarction. Secondary outcome measures were the incidence of transcranial Doppler/angiographic vasospasm, the neuronal markers (neuron-specific enolase, S-100), and the patients' Glasgow Outcome Scale scores at discharge and after 1 year.

RESULTS

One hundred and four patients met the study requirements. In the magnesium group (n = 53), eight patients (15%) experienced clinical vasospasm and 20 (38%) experienced transcranial Doppler/angiographic vasospasm compared with 14 (27%) and 17 (33%) patients in the nimodipine group (n = 51). If clinical vasospasm occurred, 75% of the magnesium-treated versus 50% of the nimodipine-treated patients experienced cerebral infarction resulting in fatal outcome in 37 and 14%, respectively. Overall, the rate of infarction attributable to vasospasm was virtually the same (19 versus 22%). There was no difference in outcome between groups.

CONCLUSION

The efficacy of magnesium in preventing delayed ischemic neurological deficits in patients with aneurysmal subarachnoid hemorrhage seems to be comparable with that of nimodipine. The difference in their pharmacological properties makes studies on the combined administration of magnesium and nimodipine seem promising.

Xenon-CT and transcranial Doppler in poor-grade or complicated aneurysmatic subarachnoid hemorrhage patients undergoing aggressive management of intracranial hypertension

OBJECTIVE

To evaluate whether elevated flow velocimetry values are associated with critically reduced cerebral blood flow values in deeply sedated patients with acute aneurysmatic subarachnoid hemorrhage and in whom the detection of clinical vasospasm is not feasible.

DESIGN

Retrospective analysis of prospectively collected data.

SETTING

Neurosurgical and trauma patients in an intensive care unit in a regional hospital.

PATIENTS AND PARTICIPANTS

Twenty-nine patients in the acute phase following subarachnoid hemorrhage who were sedated and ventilated for elevated intracranial pressure, transcranial Doppler vasospasm, or respiratory failure and were studied with at least a coupled xenon-CT/transcranial Doppler study.

MEASUREMENTS AND RESULTS

Combined measurement and comparison of cerebral blood flow by means of xenon-CT and of mean velocity by means of transcranial Doppler in middle cerebral artery territories. The case mix studied was consistent with patients' predominantly poor grade and with a complicated course. The results suggest that in sedated patients flow velocity and measured cortical mixed cerebral blood flow are not correlated, and, more specifically, that flow velocities values above 120 or 160 cm/s and Lindegaard index above 3 are not associated with an ischemic regional cerebral blood flow. Conversely, as many as 55% of the xenon-CT studies were associated with hyperemia.

CONCLUSIONS

In patients with elevated intracranial pressure, mean middle cerebral artery flow velocity or Lindegaard Index does not help to detect critical cerebral blood flow nor elevated cerebral blood flow.

Magnesium sulfate: role as possible attenuating factor in vasospasm morbidity

BACKGROUND

Among the many complications of SAH, one of the most important is vasospasm. Several treatment alternatives have been proposed for this condition, with far-from-ideal results being obtained. Magnesium sulfate recently returned to the scene (with still unproven benefit) as an adjuvant in the treatment of vasospasm.

METHODS

Seventy-two patients diagnosed with SAH by aneurysm rupture were submitted to microsurgery craniotomy and subdivided in 2 groups. Group 1, formed by 48 patients, received prophylactic hypervolemic and hemodilution therapy in addition to nimodipine. Group 2, composed of 24 patients, received the same treatment of group 1 with the addition of magnesium sulfate in continuous infusion from 120 to 150 mg a day, keeping serum magnesium levels close to double normal values.

RESULTS

Age was 49 +/- 12.6 years. Ratio of female to male was 3.16:1. Most patients were admitted in a Hunt-Hess grade 2 (46.4%) and Fisher grade 3 (52.8%). Anterior communicating artery aneurysms were the most common in location (38.8%). Both groups were compared, and there was no statistical difference related to age, sex, and Glasgow, Fisher, or Hunt-Hess admission grades. No statistical difference in vasospasm incidence was found between the two groups. However, in group 1, vasospasm was correlated with a longer hospitalization time (P = .0003), different from group 2, in which patients with vasospasm receiving magnesium sulfate required less hospitalization time.

CONCLUSION

Magnesium did not seem to interfere in vasospasm frequency but apparently acted favorably in decreasing morbidity and length of hospital stay.

Controversies in the management of aneurysmal subarachnoid hemorrhage*

BACKGROUND

The care of patients with aneurysmal subarachnoid hemorrhage has evolved significantly with the advent of new diagnostic and therapeutic modalities. Although it is believed that these advances have contributed to improved outcomes, considerable uncertainty persists regarding key areas of management.

OBJECTIVE

To review selected controversies in the management of aneurysmal subarachnoid hemorrhage, with a special emphasis on endovascular vs. surgical techniques for securing aneurysms, the diagnosis and therapy of cerebral vasospasm, neuroprotection, antithrombotic and anticonvulsant agents, cerebral salt wasting, and myocardial dysfunction, and to suggest venues for further clinical investigation.

DATA SOURCE

Search of MEDLINE and Cochrane databases and manual review of article bibliographies.

DATA SYNTHESIS AND CONCLUSIONS

Many aspects of care in patients with aneurysmal subarachnoid hemorrhage remain highly controversial and warrant further resolution with hypothesis-driven clinical or translational research. It is anticipated that the rigorous evaluation and implementation of such data will provide a basis for improvements in short- and long-term outcomes.

Cerebral vasospasm: a consideration of the various cellular mechanisms involved in the pathophysiology

The cellular mechanisms responsible for cerebral vasospasm (CVS) occurring after subarachnoid hemorrhage (SAH) have been of major interest over the past 50 years. The present review describes how each of the discrete anatomic components that comprise the cerebral artery may contribute to the pathology of CVS. The blood extravasated after SAH is hemolyzed and undergoes degradation with resultant production of free radicals, known to be powerful initiators of vascular damage. An inflammatory response is generated activating both leukocytes and platelets with subsequent release of inflammatory agents. The cerebral artery affected by CVS undergoes phenotypic change involving both the endothelial and smooth muscle cells. In the endothelium the production of nitric oxide and prostacyclin is affected. In the smooth muscle cells signal transduction pathways that enhance the function of the contractile proteins and induce the upregulation of contractile receptors are activated. In parallel, there is evidence that nervous reflex pathways involving the trigeminal ganglion and the hypothalamus are activated. However, the relative contributions of each of the systems are speculative. Therapy may be directed at disrupting the cascade leading from the SAH insult to CVS or at overcoming the dysfunction incurred by CVS; possible therapeutical interventions are considered.

Prediction of Cerebral Vasospasm in Patients Presenting with Aneurysmal Subarachnoid Hemorrhage: A Review

OBJECTIVE:

Cerebral vasospasm is a devastating medical complication of aneurysmal subarachnoid hemorrhage (SAH). It is associated with high morbidity and mortality rates, even after the aneurysm has been treated. A substantial amount of experimental and clinical research has been conducted in an effort to predict and prevent its occurrence. This research has contributed to significant advances in the understanding of the mechanisms leading to cerebral vasospasm. The ability to accurately and consistently predict the onset of cerebral vasospasm, however, has been challenging. This topic review describes the various methodologies and approaches that have been studied in an effort to predict the occurrence of cerebral vasospasm in patients presenting with SAH.

METHODS:

The English-language literature on the prediction of cerebral vasospasm after aneurysmal SAH was reviewed using the MEDLINE PubMed (1966–present) database.

RESULTS:

The risk factors, diagnostic imaging, bedside monitoring approaches, and pathological markers that have been evaluated to predict the occurrence of cerebral vasospasm after SAH are presented.

CONCLUSION:

To date, a large blood burden is the only consistently demonstrated risk factor for the prediction of cerebral vasospasm after SAH. Because vasospasm is such a multifactorial problem, attempts to predict its occurrence will probably require several different approaches and methodologies, as is done at present. Future improvements in the prevention of cerebral vasospasm from aneurysmal SAH will most likely require advances in our understanding of its pathophysiology and our ability to predict its onset.

Correlation of serum brain natriuretic peptide with hyponatremia and delayed ischemic neurological deficits after subarachnoid hemorrhage

OBJECTIVE

Serum brain natriuretic peptide (BNP) is elevated after subarachnoid hemorrhage (SAH), causes diuresis and natriuresis (cerebral salt wasting), and may exacerbate delayed ischemic neurological deficits. We examined the temporal relationship between serum BNP elevation, hyponatremia, and the onset of delayed ischemic neurological deficits and determined whether serum BNP levels correlated with the 2-week outcome after SAH.

METHODS

Serum BNP and sodium were measured prospectively every 12 hours for 14 days in 40 consecutive patients admitted with SAH. All patients remained euvolemic, underwent transcranial Doppler assessment every 48 hours, and underwent angiography at the onset of delayed neurological deficits. New-onset neurological deficits were attributed to vasospasm only in the absence of other causes and when supported by transcranial Doppler or cerebral angiography.

RESULTS

Sixteen patients (40%) experienced symptomatic cerebral vasospasm after SAH. A more than threefold increase in admission serum BNP was associated with the onset of hyponatremia (P < 0.05). Mean BNP levels were similar between vasospasm and nonvasospasm patients fewer than 3 days after SAH (126 +/- 39 pg/ml versus 154 +/- 40 pg/ml; P = 0.61) but were elevated in the vasospasm cohort 4 to 6 days after SAH (285 +/- 67 pg/ml versus 116 +/- 30 pg/ml; P < 0.01), 7 to 9 days after SAH (278 +/- 72 pg/ml versus 166 +/- 45 pg/ml; P < 0.01), and 9 to 12 days after SAH (297 +/- 83 pg/ml versus 106 +/- 30 pg/ml; P < 0.01). BNP level remained independently associated with vasospasm adjusting for Fisher grade and Hunt and Hess grade (odds ratio, 1.28; 95% confidence interval, 1.1-1.6). In patients in whom vasospasm developed, mean serum BNP increased 5.4-fold within 24 hours after vasospasm onset and 11.2-fold the first 3 days after vasospasm onset. Patients with increasing BNP levels from admission demonstrated no change (0 +/- 3) in Glasgow Coma Scale score 2 weeks after SAH versus a 3.0 +/- 2 (P < 0.05) improvement in Glasgow Coma Scale score in patients without increasing serum BNP levels.

CONCLUSION

Increasing serum BNP levels independently were associated with hyponatremia, significantly increased the first 24 hours after onset of delayed ischemic neurological deficits, and predicted the 2-week Glasgow Coma Scale score.

Reduction of ischemic sequelae following spontaneous subarachnoid hemorrhage: a double-blind, randomized comparison of enoxaparin versus placebo

BACKGROUND

Cerebral vasospasm, including its ischemic sequelae, remains a leading cause of death and disability following subarachnoid hemorrhage (SAH). This study was designed to evaluate whether the low-molecular-weight heparin (LMWH) enoxaparin reduces the occurrence of cerebral vasospasm and ischemia following spontaneous SAH.

METHODS

A prospective, double-blind, randomized study was conducted in 120 consecutive patients with SAH (Hunt Hess Scale (HHS) I-III). Patients received one subcutaneous injection per day of either 20mg enoxaparin or placebo for 3 weeks following SAH. Efficacy endpoints were the occurrence of cerebral vasospasm, delayed ischemic deficit (DID), cerebral infarction, and overall outcome at 1 year following SAH.

RESULTS

At 1-year follow-up, enoxaparin significantly reduced DID and cerebral infarction. Delayed ischemic deficit occurred in 8.8% of the enoxaparin group versus 66.7% of the placebo group (P<0.001), while 3.5% of vasospasm-related cerebral infarctions occurred in enoxaparin-treated patients and 28.3% in placebo-treated patients (P<0.001). Severe shunt-dependent hydrocephalus was significantly lower in the enoxaparin group (1.8% versus 16.7%; P=0.019). Compared with the placebo group, the enoxaparin group had fewer intracranial bleeding events and better overall outcomes at 1-year follow-up. Although there was potential bias as a result of patients in the placebo group being more severely affected (in terms of HHS), treatment with enoxaparin for 3 weeks improved long-term outcome following SAH.

CONCLUSIONS

Enoxaparin is safe and effective in reducing cerebral vasospasm and ischemia following SAH (Hunt Hess grades I-III), resulting in a better long-term outcome for the patient.

Standardization of flow velocities with respect to age and sex improves the accuracy of transcranial color Doppler sonography of middle cerebral artery spasm

OBJECTIVE

The overall accuracy of transcranial Doppler sonography in the diagnosis of middle cerebral artery spasm has not been established. Moreover, the factors of age and sex have not been addressed in most studies. In this article, we present receiver operating characteristic (ROC) curve analysis of the accuracy of transcranial color Doppler sonography in diagnosing middle cerebral artery spasm on the basis of flow velocities standardized for age and sex. SUBJECTS AND METHODS. We prospectively studied 214 consecutive patients (110 male, 104 female; age range, 12-77 years) who were routinely referred for cerebral angiography. Middle cerebral artery spasm was graded as mild (</= 25% of vessel caliber reduction) and moderate to severe (> 25% reduction). Angle-corrected blood velocity measurements were obtained using a 2.5-MHz probe. The velocity values were reexpressed as a percentage of the mean of normal reference values for the relevant age, for subjects younger than 40 years, and for sex.

RESULTS

The prevalence of spasm among 335 arteries studied was 8.1% for mild and 12.8% for moderate to severe middle cerebral artery narrowing. For distinguishing all or moderate to severe vasospasm from lesser grades of vasospasm, peak systolic velocity was the best parameter. Areas under ROC curves for all and moderate to severe middle cerebral artery spasms were 0.83 and 0.92, respectively. After standardization, the ROC areas increased significantly (p < 0.05) for all, to 0.86, and only slightly, to 0.93, for moderate to severe spasms. For all grades of middle cerebral artery spasm, the best efficiencies were found at standardized velocity value of 170%.

CONCLUSION

The accuracy of transcranial color Doppler sonography is high in the identification of middle cerebral artery spasm. Standardization of velocities with respect to age and sex increases the accuracy of the method in diagnosing mild middle cerebral artery spasms.

Serum von Willebrand factor, matrix metalloproteinase-9, and vascular endothelial growth factor levels predict the onset of cerebral vasospasm after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Endothelial damage and intimal proliferation occur in vasospastic cerebral arteries after subarachnoid hemorrhage (SAH). In the peripheral vasculature, endothelial damage increases intimal matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF) levels, causing neointimal proliferation. We hypothesized that serum von Willebrand factor (vWF) (a marker of endothelial cell death), MMP-9, and VEGF levels could serve as prognostic markers in predicting the occurrence of cerebral vasospasm.

METHODS

Venous serum vWF, MMP-9, and VEGF levels were prospectively measured daily, for 12 days or until the onset of vasospasm, for 45 consecutive patients admitted with SAH (n = 38) or admitted for elective aneurysm clipping (control subjects, n = 7). The development of transcranial Doppler flow velocities of more than 180 cm/s and/or new focal neurological deficits with angiographically confirmed vasospasm was considered the onset of vasospasm. To establish whether these markers were specific for vasospasm versus ischemia, blood samples were obtained from a concurrent group of 42 patients within 24 hours after stroke onset unrelated to SAH.

RESULTS

Fifty-seven percent of patients (22 of 38 patients) developed vasospasm, 4 to 11 days after SAH (median, 7 d). Mean peak serum vWF, MMP-9, and VEGF levels were increased in the SAH prevasospasm cohort, compared with the SAH nonvasospasm cohort (vWF, 5526 +/- 929 versus 4934 +/- 599 ng/ml, P = 0.01; MMP-9, 705 +/- 338 versus 438 +/- 154 ng/ml, P = 0.006; VEGF, 0.12 +/- 0.06 versus 0.06 +/- 0.06 ng/ml, P = 0.023). Mean peak vWF, MMP-9, and VEGF levels for the focal ischemia cohort (vWF, 4645 +/- 875 ng/ml, P = 0.01; MMP-9, 250 +/- 308 ng/ml, P = 0.001; VEGF, 0.03 +/- 0.04 ng/ml, P = 0.001) were markedly lower in comparison with the SAH prevasospasm cohort and were unchanged in comparison with the control cohort. vWF levels of more than 5500 ng/ml, VEGF levels of more than 0.12 ng/ml, and MMP levels of more than 700 ng/ml each independently increased the odds of subsequent vasospasm (18-, 20-, and 25-fold, respectively).

CONCLUSION

The development of cerebral vasospasm after SAH was preceded by increases in serum vWF, MMP-9, and VEGF levels. Increased serum vWF, MMP-9, and VEGF levels could accurately predict the onset of cerebral vasospasm after SAH. These factors were not elevated by SAH alone or in a separate cohort of patients with ischemic stroke, suggesting that these factors might play a role in the pathogenesis of human cerebral vasospasm.

Transcranial Doppler assessment of cerebral vasospasm

This review summarizes the use of transcranial Doppler (TCD) for assessment of cerebral vasospasm. The basic hemodynamic principles are presented, and used as a basis for discussing findings and interpretation methods. The need for additional information and measurements to correctly interpret TCD velocities is analyzed, and the use of a special extracranial Doppler technique is recommended. The advantages and limitations of the 'Lindegaard Index' (LI) are discussed. The recent advances in the use of TCD for cerebral autoregulation testing are opening up a new and promising avenue in diagnosis, monitoring and treatment of cerebral vasospasm.

Evaluation of vasospasm after subarachnoid hemorrhage by use of multislice computed tomographic angiography

OBJECTIVE

Multislice computed tomographic angiography (CTA) can provide clearer vascular images, even of the peripheral arteries, than conventional CTA. Multislice CTA was compared with digital subtraction angiography (DSA) for the detection of cerebral vasospasm in patients with acute aneurysmal subarachnoid hemorrhage (SAH) to analyze whether multislice CTA can replace DSA in the detection of vasospasm after SAH.

METHODS

Within 72 hours after the onset of symptoms, multislice CTA and DSA were performed in 20 patients with SAH. Multislice CTA and DSA were repeated on Day 7 to assess cerebral vasospasm. Regions of interest were established in the proximal and distal segments of the anterior and middle cerebral arteries on both multislice CTA and DSA images, and the agreement between the severity of vasospasm on multislice CTA and DSA images was statistically compared. The multislice Aquilon computed tomography system (Toshiba, Inc., Tokyo, Japan) used the following parameters: 1 mm collimation and 3.5 mm per rotation table increment (pitch, 3.5).

RESULTS

The degree of vasospasm as revealed by multislice CTA correlated significantly with the degree of vasospasm revealed by DSA (P < 0.0001). The agreement between the severity of vasospasm on multislice images obtained via CTA and DSA in the overall, proximal, and distal segments of the cerebral arteries was 91.6, 90.8, and 92.3%, respectively.

CONCLUSION

Multislice CTA can detect angiographic vasospasm after SAH with accuracy equal to that of DSA.

Cerebral vasospasm and ischaemic infarction in clipped and coiled intracranial aneurysm patients

The influence of the treatment modalities (clipping/coiling) on the incidence of vasospasm and ischaemic infarction in aneurysm patients is still judged controversially. The purpose of this study was to analyse and compare retrospectively cerebral vasospasm and ischaemic infarction, as well as neurological deficits and outcome within a large population of clipped and coiled patients with ruptured and unruptured aneurysms. Within a 2-year period, a total of 144 interventions (53 clipping/91 coiling) entered the study. Daily bilateral transcranial Doppler sonographic monitoring was performed to observe vasospasm development. All cerebral computed tomography (cCT) and magnetic resonance imaging (MRI) scans were reviewed with respect to occurrence and localization of ischaemic infarctions. Focal neurological deficits were recorded and clinical outcome was evaluated using the Glasgow Outcome Scale. Statistical analysis included the use of multivariate logistic regression models to find determinants of vasospasm, ischaemic infarction and neurological deficits. Altogether, vasospasm was detected after 77 (53.5%) interventions, 61.8% in females (P < 0.01). Clipped patients significantly more often exhibited vasospasms (69.8 vs. 44.0%, P < 0.005) and were treated 1 week longer at the intensive care unit (P < 0.005). Seventy-seven patients (53.5%) developed ischaemic infarctions, 62.3% after clipping and 48.4% after coiling (P > 0.05). In the multivariate analysis, aneurysm-rupture was the strongest predictor for vasospasm and vasospasm was the strongest predictor for infarction. Neurological deficits at discharge (46.5%) were independent of treatment modality, the same applied for the mean Glasgow Outcome Scores. There was no significant difference in mortality between surgical and endovascular treatment (9.4 vs. 12.1%). Whilst the vasospasm incidence was significantly higher after surgical treatment, ischaemic infarctions were only slightly more frequent. The incidence of neurological deficits and clinical outcome was similar in both treatment groups.

Accuracy of transcranial color Doppler ultrasonography in the diagnosis of middle cerebral artery spasm determined by receiver operating characteristic analysis

OBJECT

The value of transcranial Doppler ultrasonography for the detection of middle cerebral artery (MCA) spasm has been asserted. None of the published studies, however, has adequately scrutinized the overall diagnostic accuracy of this procedure. There are only sporadic reports concerning the utility of transcranial color Doppler (TCCD) ultrasonography, although this method has been proved to be more precise. In this study the authors attempted to estimate the performance of TCCD ultrasonography in detecting MCA narrowing by using receiver operating characteristic (ROC) curve analysis, based on TCCD studies obtained in a relatively large, randomly selected population of patients.

METHODS

Transcranial color Doppler ultrasonography studies were obtained in 100 consecutive patients (54 men and 46 women ages 18-74 years, median age 50 years) routinely referred by neurosurgeons for intraarterial angiography. The M1 segment of the MCA was insonated using a 2.5-MHz probe via a temporal acoustic window, and angle-corrected flow velocities were obtained. Angiographically depicted vasospasm was graded as none, mild (< or = 25% vessel caliber reduction), and moderate to severe (> 25% vessel caliber reduction). The effectiveness of TCCD ultrasonography in diagnosing MCA spasm was evaluated by calculating the areas under the ROC curves (Az). Of the 200 MCAs examined, 173 were successfully visualized with the aid of TCCD ultrasonography. Mild vasospasm was angiographically diagnosed in 15 arteries and moderate-to-severe vasospasm in 28. The best-performing TCCD parameter for the detection of MCA narrowing was revealed to be peak systolic velocity. The Az value for moderate-to-severe vasospasm only was 0.93 and that for all vasospasms was 0.8. The best efficiency, that is, the optimal tradeoff between sensitivity and specificity in diagnosing vasospasms, was associated with a peak systolic velocity of 182 cm/second.

CONCLUSIONS

The performance of TCCD ultrasonography in the diagnosis of advanced MCA narrowing is very good, and is acceptable for all vasospasms. The best-performing parameter was peak systolic velocity.

Transcranial Doppler versus angiography in patients with vasospasm due to a ruptured cerebral aneurysm: A systematic review

BACKGROUND AND PURPOSE

Transcranial Doppler (TCD) is used for diagnosis of vasospasm in patients with subarachnoid hemorrhage due to a ruptured aneurysm. Our aim was to evaluate both the accuracy of TCD compared with angiography and its usefulness as a screening method in this setting.

METHODS

A search (MEDLINE, EMBASE, Cochrane Library, bibliographies, hand searching, any language, through January 31, 2001) was performed for studies comparing TCD with angiography. Data were critically appraised using a modified published 10-point score and were combined using a random-effects model.

RESULTS

Twenty-six reports compared TCD with angiography. Median validity score was 4.5 (range 1 to 8). Meta-analyses could be performed with data from 7 trials. For the middle cerebral artery (5 trials, 317 tests), sensitivity was 67% (95% CI 48% to 87%), specificity was 99% (98% to 100%), positive predictive value (PPV) was 97% (95% to 98%), and negative predictive value (NPV) was 78% (65% to 91%). For the anterior cerebral artery (3 trials, 171 tests), sensitivity was 42% (11% to 72%), specificity was 76% (53% to 100%), PPV was 56% (27% to 84%), and NPV was 69% (43% to 95%). Three of these 7 studies reported on the same patients, each on another artery, and for 4, data recycling could not be disproved. Other arteries were tested in only 1 trial each.

CONCLUSIONS

For the middle cerebral artery, TCD is not likely to indicate a spasm when angiography does not show one (high specificity), and TCD may be used to identify patients with a spasm (high PPV). For all other situations and arteries, there is either lack of evidence of accuracy or of any usefulness of TCD. Most of these data are of low methodological quality, bias cannot not be ruled out, and data reporting is often uncritical.

Review of medical prevention of vasospasm after aneurysmal subarachnoid hemorrhage: a problem of neurointensive care

Cerebral vasospasm remains a devastating medical complication of aneurysmal subarachnoid hemorrhage (SAH). It is associated with high morbidity and mortality rates, even after the aneurysm has been secured surgically or radiologically. A great deal of experimental and clinical research has been conducted in an effort to find ways to prevent this complication. The literature includes extensive coverage of in vivo animal model studies of SAH and vasospasm. These experimental studies have contributed to tremendous advances in the understanding of the mechanisms leading to cerebral vasospasm. Most of the experimental settings, however, have demonstrated varying levels of ability to predict accurately what occurs in human SAH. Therefore, although animal models have been developed to test new therapies, most of the treatment effects have been shown to be less compelling when trials have been conducted in clinical settings. The interpretation of current literature is complicated further by the imprecise estimation of the incidence of cerebral vasospasm, which is due to various degrees of clinical expression, ranging from the absence of symptoms in the presence of increased blood flow velocities at transcranial Doppler or vessel diameter reduction at angiography to neurological manifestations of severe ischemic deficits. In addition, a change over time in the incidence pattern of human SAH and vasospasm, possibly related to improved surgical techniques and overall patient management, may have occurred. This topic review collects the relevant literature on clinical trials investigating prophylactic therapies for cerebral vasospasm in patients with aneurysmal SAH and emphasizes the need for large clinical trials to confirm the results derived from clinical experience. In addition, it points out some experimental therapies that may hold promise in future clinical trials to prevent the occurrence of vasospasm.

Subarachnoid haemorrhage: diagnosis, causes and management

The incidence of subarachnoid haemorrhage (SAH) is stable, at around six cases per 100 000 patient years. Any apparent decrease is attributable to a higher rate of CT scanning, by which other haemorrhagic conditions are excluded. Most patients are <60 years of age. Risk factors are the same as for stroke in general; genetic factors operate in only a minority. Case fatality is approximately 50% overall (including pre-hospital deaths) and one-third of survivors remain dependent. Sudden, explosive headache is a cardinal but non-specific feature in the diagnosis of SAH: in general practice, the cause is innocuous in nine out of 10 patients in whom this is the only symptom. CT scanning is mandatory in all, to be followed by (delayed) lumbar puncture if CT is negative. The cause of SAH is a ruptured aneurysm in 85% of cases, non-aneurysmal perimesencephalic haemorrhage (with excellent prognosis) in 10%, and a variety of rare conditions in 5%. Catheter angiography for detecting aneurysms is gradually being replaced by CT angiography. A poor clinical condition on admission may be caused by a remediable complication of the initial bleed or a recurrent haemorrhage in the form of intracranial haematoma, acute hydrocephalus or global brain ischaemia. Occlusion of the aneurysm effectively prevents rebleeding, but there is a dearth of controlled trials assessing the relative benefits of early operation (within 3 days) versus late operation (day 10-12), or that of endovascular treatment versus any operation. Antifibrinolytic drugs reduce the risk of rebleeding, but do not improve overall outcome. Measures of proven value in decreasing the risk of delayed cerebral ischaemia are a liberal supply of fluids, avoidance of antihypertensive drugs and administration of nimodipine. Once ischaemia has occurred, treatment regimens such as a combination of induced hypertension and hypervolaemia, or transluminal angioplasty, are plausible, but of unproven benefit.

Management and outcomes in a low-volume cerebral aneurysm practice

OBJECTIVE

To review management strategies, outcomes, and complications in cerebral aneurysm surgery in a low-volume aneurysm practice.

METHODS

Seventy-nine craniotomies to treat aneurysms were performed between June 1996 and November 1999. Patient management strategy is outlined, complications are assessed, and outcomes are described.

RESULTS

Twenty-six patients underwent surgery to treat unruptured aneurysms. Forty-two patients presented with Hunt and Hess Grade 1 to 3 subarachnoid hemorrhage. Eleven patients presented with Grade 4 or 5 subarachnoid hemorrhage. Twenty-four patients (92.3%) with unruptured aneurysms experienced favorable outcomes. Of the patients with unruptured anterior circulation aneurysms, 96% achieved favorable recoveries. Thirty-eight patients (90.5%) with Grade 1 to 3 subarachnoid hemorrhage experienced favorable outcomes; four of these patients were moderately disabled. Among patients with Grade 1 to 3 subarachnoid hemorrhage, the mortality rate was 7.1%. Of patients with Grade 4 or 5 subarachnoid hemorrhage, five (45.5%) experienced favorable outcomes, but four of these patients were moderately disabled; two patients (18.2%) were severely disabled, and four patients (36.4%) died.

CONCLUSION

Acceptable clinical outcomes can be achieved in lower-volume aneurysm practices. A multidisciplinary subspecialty approach with aggressive perioperative care, especially in the prevention and treatment of cerebral vasospasm, is important in obtaining these results. Close interaction with medical consultants and other subspecialists is necessary.