Value of computed tomography in the prediction of cerebral vasospasm after aneurysm rupture

Transcranial-Doppler-Measured Vasospasm Severity is Associated with Delayed Cerebral Infarction After Subarachnoid Hemorrhage

BACKGROUND

Angiographic vasospasm after aneurysmal subarachnoid hemorrhage (aSAH) is associated with delayed cerebral ischemia (DCI)-related cerebral infarction (radiological DCI) and worsened neurological outcome. Transcranial Doppler (TCD) measurements of cerebral blood flow velocity are commonly used after aSAH to screen for vasospasm; however, their association with cerebral infarction is not well characterized. We sought to determine whether time-varying TCD-measured vasospasm severity is associated with cerebral infarction and investigate the performance characteristics of different time/severity cutoffs for predicting cerebral infarction.

METHODS

We conducted a retrospective single-center cohort study of consecutive adult patients with aSAH with at least one TCD study between 2011 and 2020. The primary outcome was radiological DCI, defined as a cerebral infarction developing at least 2 days after any surgical or endovascular intervention without an alternative cause. Cox proportional hazards models were used to examine associations between time-varying vasospasm severity and radiological DCI. Optimal TCD-based time/severity thresholds for predicting radiological DCI were then determined.

RESULTS

Of 262 patients with aSAH who underwent TCD studies, 27 (10%) developed radiological DCI. Patients with radiological DCI had higher modified Fisher scale scores and trended toward earlier onset of vasospasm. Adjusted for age, Hunt and Hess scores, and modified Fisher scale scores, the worst-vessel vasospasm severity was associated with radiological DCI (adjusted hazard ratio 1.7 [95% confidence interval 1.1-2.4]). Vasospasm severity within a specific vessel was associated with risk of delayed infarction in the territory supplied by that vessel. Optimal discrimination of patients with radiological DCI was achieved with thresholds of mild vasospasm on days 4-5 or moderate vasospasm on days 6-9, with negative predictive values greater than 90% and positive predictive values near 20%.

CONCLUSIONS

TCD-measured vasospasm severity is associated with radiological DCI after aSAH. An early, mild TCD-based vasospasm severity threshold had a high negative predictive value, supporting its role as a screening tool to identify at-risk patients.

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

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

Spontaneous Subarachnoid Hemorrhage: Assessment of Prognosis and Initial Management in the Intensive Care Unit

Spontaneous subarachnoid hemorrhage (SAH) is asso ciated with high morbidity and mortality. Primary con servative or preoperative management in the intensive care unit aims at prevention, early detection, and treat ment of complications. In this article we review the literature on the value of initial clinical and laboratory findings in predicting complications and outcome after SAH. Current conservative management of SAH is briefly discussed.

Current controversies in the prediction, diagnosis, and management of cerebral vasospasm: where do we stand?

Aneurysmal subarachnoid hemorrhage occurs in approximately 30,000 persons in the United States each year. Around 30 percent of patients with aneurysmal subarachnoid hemorrhage suffer from cerebral ischemia and infarction due to cerebral vasospasm, a leading cause of treatable death and disability following aneurysmal subarachnoid hemorrhage. Methods used to predict, diagnose, and manage vasospasm are the topic of recent active research. This paper utilizes a comprehensive review of the recent literature to address controversies surrounding these topics. Evidence regarding the effect of age, smoking, and cocaine use on the incidence and outcome of vasospasm is reviewed. The abilities of different computed tomography grading schemes to predict vasospasm in the aftermath of subarachnoid hemorrhage are presented. Additionally, the utility of different diagnostic methods for the detection and visualization of vasospasm, including transcranial Doppler ultrasonography, CT angiography, digital subtraction angiography, and CT perfusion imaging is discussed. Finally, the recent literature regarding interventions for the prophylaxis and treatment of vasospasm, including hyperdynamic therapy, albumin, calcium channel agonists, statins, magnesium sulfate, and endothelin antagonists is summarized. Recent studies regarding each topic were reviewed for consensus recommendations from the literature, which were then presented.

Effect of clot removal and the different incidence of vasospasm between clipping and GDC

The removal of subarachnoid clot has been thought to be effective for prevention of cerebral vasospasm. However, it is suggested that the incidence of cerebral vasospasm is not high in the cases where ruptured cerebral aneurysms are obliterated using Guglielmi detachable coils (GDC) without clot removal. The effect of subarachnoid clot removal on the occurrence of cerebral vasospasm and the different incidence of cerebral vasospasm between clipping cases and in GDC cases are reviewed.Surgical clot removal in experimental model indicated marked preventive effect on cerebral vasospasm. However, the clinical trials of clot removal during early aneurysm surgery had failed to show satisfactory preventive effect for vasospasm, and the cumulative incidence of symptomatic vasospasm in these trials was 29%. As fibrinolytic drug, intrathecal administration of tissue plasminogen activator showed sufficient elimination of subarachnoid clot and prevention of cerebral vasospasm in the experimental studies and in the clinical case trials and nonrandomized case-control trials. However, the multi-center, randomized case-control trial showed no statistically significant effect on symptomatic cerebral vasospasm. On the other hand, the cumulative incidence of cerebral vasospasm in GDC cases was 20%. The comparative studies of the incidence of vasospasm between GDC cases and in clipping cases also showed less incidence of symptomatic vasospasm and a more favorable outcome in GDC cases. From the results of studies reviewed, the incidence of cerebral vasospasm seems less in GDC cases than in clipping cases. It should be clarified why clipping could not be dominant in the prevention of cerebral vasospasm compared to GDC.

Timing of computed tomography and prediction of vasospasm after aneurysmal subarachnoid hemorrhage

BACKGROUND

The initial noncontrast computed tomography (CT) study of the head after an aneurysmal subarachnoid hemorrhage (SAH) is used to predict the risk of developing vasospasm. Changes in the extent of subarachnoid blood seen on CT images occur as a function of time after SAH, but there is no consensus on the time interval during which this study needs to be completed.

METHODS

Clinical and radiological information on adult SAH patients were reviewed. Patients were grouped based on the time elapsed from ictus to the initial head CT study. The amount of subarachnoid blood on CT was graded using the Hijdra sum score (HSS) and the modified Fisher scale (MFS). The relationship between the initial CT grading score and the risk of angiographic vasospasm was assessed for each group.

RESULTS

A total of 224 consecutive patients were identified (145 females, 65%). Initial CT was performed within 24 h of the event in 163 (Group 1, 73%) and after 24 h in 61 patients (Group 2, 27%). A total of 54 patients (24%) developed angiographic vasospasm. A statistically significant association between the extent of subarachnoid blood and subsequent development of vasospasm was observed only if the initial CT imaging study was performed within 24 h of aneurysmal rupture (P = 0.0001 and 0.02 for HSS and MFS, respectively).

CONCLUSIONS

We propose that only CT scans obtained within 24 h of a subarachnoid bleeding event should be used to estimate the risk of vasospasm.

Traitement de l'hémorragie méningée anévrismale

The incidence of subarachnoid hemorrhages is about 10.5/100,000 persons/year. Early obliteration of the aneurysmal sac is necessary to avoid rebleeding. The neurovascular staff meeting must decide the appropriate obliteration procedure for each patient. Intraoperative morbidity is 8% after endovascular coiling and 10% after microsurgical clipping. Endovascular coiling leads to complete obliteration of the aneurysm in 60% of patients and microsurgical clipping in 95%. Delayed ischemic deficits may be prevented by volemic expansion and calcium channel blockers. Hospitalization and general prophylaxis against deep venous thrombosis, pain and seizures are essential. Curative treatment is required against common complications such as intraparenchymatous hematoma, hydrocephalus, and delayed ischemic deficit.

Using CT in the Diagnosis and Management of Patients with Cerebral Vasospasm

Cerebral vasospasm remains a serious complication of aneurysmal subarachnoid hemorrhage. Efforts in improving its clinical outcome have been focused on early diagnosis and applying effective treatment regimens. Standard diagnostic modalities currently used do not fully address this complex disease. The use of CT angiography and CT perfusion are discussed, with emphasis on its potential role in not only detecting vasospasm, but also in guiding management decisions and assessing clinical outcome.

Cerebral vasospasm in patients with unruptured intracranial aneurysms

Intracranial arterial vasospasm is a typical sequela of subarachnoid haemorrhage. The association between symptomatic vasospasm and unruptured aneurysms has been sporadically presented in the literature. The pathogenesis of this unusual entity is unclear. The published cases were collected in this review and analysed with regard to timing, clinical presentation and possible relationship with surgical factors. We also added an illustrative case which was recently observed in our department.

Volumetric quantification of Fisher Grade 3 aneurysmal subarachnoid hemorrhage: a novel method to predict symptomatic vasospasm on admission computerized tomography scans

OBJECT

Predicting which patients with aneurysmal subarachnoid hemorrhage (SAH) will develop delayed ischemic neurological deficit (DIND) due to vasospasm remains subjective and unreliable. The authors analyzed the utility of a novel software-based technique to quantify hemorrhage volume in patients with Fisher Grade 3 aneurysmal SAH.

METHODS

Patients with aneurysmal SAH in whom a computerized tomography (CT) scan was performed within 72 hours of ictus and demonstrated Fisher Grade 3 SAH were analyzed. Severe DIND was defined as new onset complete focal deficit or coma. Moderate DIND was defined as new onset partial focal deficit or impaired consciousness without coma. Fifteen consecutive patients with severe DIND, 13 consecutive patients with moderate DIND, and 12 consecutive patients without DIND were analyzed. Software-based volumetric quantification was performed on digitized admission CT scans by a single examiner blinded to clinical information. There was no significant difference in age, sex, admission Hunt and Hess grade, or time to admission CT scan among the three groups (none, moderate, or severe DIND). Patients with severe DIND had a significantly higher cisternal volume of hemorrhage (median 30.5 cm3) than patients with moderate DIND (median 12.4 cm3) and patients without DIND (median 10.3 cm3; p < 0.001). Intraparenchymal hemorrhage and intraventricular hemorrhage were not associated with DIND. All 13 patients with cisternal volumes greater than 20 cm3 developed DIND, compared with 15 of 27 patients with volumes less than 20 cm3 (p = 0.004).

CONCLUSIONS

The authors developed a simple and potentially widely applicable method to quantify SAH on CT scans. A greater volume of cisternal hemorrhage on an admission CT scan in patients with Fisher Grade 3 aneurysmal SAH is highly associated with DIND. A threshold of cisternal hemorrhage volume (> 20 cm3) may exist above which patients are very likely to develop DIND. Prospective application of software-based volumetric quantification of cisternal SAH may predict which patients will develop DIND.

Early identification of patients at risk for symptomatic vasospasm after aneurysmal subarachnoid hemorrhage

OBJECTIVE

To develop a scheme for early identification of individuals at risk for symptomatic vasospasm after subarachnoid hemorrhage (SAH).

DESIGN

Analysis of prospectively collected data from the placebo-treated group in a multicenter clinical trial.

SETTINGS

Fifty-four neurosurgical centers in North America.

MEASUREMENTS AND MAIN RESULTS

We identified independent predictors of symptomatic vasospasm using stepwise logistic regression analysis from demographic, clinical, laboratory, and neuroimaging characteristics of the participants. We developed a scoring system (symptomatic vasospasm risk index) based on a combination of these predictors. Out of 283 patients in the analysis (all treated with oral nimodipine), 93 (33%) developed symptomatic vasospasm within 14 days after SAH. There were four independent predictors of symptomatic vasospasm: thickness of subarachnoid clot on computed tomographic scan (odds ratio [OR], 4.1; 95% confidence interval [CI], 1.8-10.0); early rise in middle cerebral artery mean flow velocity (MCA-MFV), defined as a value > or =110 cm/sec recorded on or before post-SAH day 5 (OR, 1.9; 95% CI, 1.1-3.3), Glasgow Coma Scale score <14 (OR, 1.8; 95% CI, 1.1-3.1); and rupture of anterior cerebral or internal carotid artery aneurysm (OR, 1.9; 95% CI, 1.0-3.4). The probability of identifying patients who would develop symptomatic vasospasm (percentage of area under receiver operating characteristics curve +/- SEM) was higher with symptomatic vasospasm risk index (68%+/-8%) compared with thickness of clot (62%+/-8%; p = .08) or MCA-MFV (45%+/-7%, p < .05) criteria alone.

CONCLUSIONS

Patients at high risk for symptomatic vasospasm can be identified early in the course of SAH using a risk index. A risk index based on a combination of variables may represent a predictive paradigm superior to conventionally used criteria based on clot thickness or MCA-MFV criteria.

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

OBJECTIVE

Transcranial Doppler (TCD) findings for evaluation of the severity of vasospasm (VSP) in patients with ruptured aneurysmal subarachnoid hemorrhage are controversial. To clarify these TCD findings, intra-arterial digital subtraction angiography was used to simultaneously investigate the angiographic features of cerebral vessels and the cerebral circulation time (CCT).

METHODS

Fifty patients with ruptured aneurysms, for whom computed tomographic scans indicated Fisher Grade III subarachnoid hemorrhage, were investigated. Aneurysmal neck clipping was performed in the acute stage. The mean flow velocity (MFV) at the M1 segment was measured using TCD ultrasonography. Intra-arterial digital subtraction angiography was used to simultaneously investigate angiographic features and CCTs on Days 7 to 13. The CCT was defined as the time difference between the two peaks in optical density curves recorded at the carotid artery (C3-C4 portion) and the ascending vein, after contrast material injection. Angiographic VSP was categorized using a modification of the Fisher classification.

RESULTS

Angiograms for 9, 25, and 16 patients showed no, slight to moderate, and severe VSP, respectively. The MFVs of the patients with no, slight to moderate, and severe VSP were 70, 115, and 116 cm/s, respectively. No significant difference among the three groups could be observed. The mean CCTs of the patients with no, slight to moderate, and severe VSP were 4.1, 4.6, and 6.5 seconds, respectively. The CCTs of the patients with severe VSP differed significantly from those of the patients with no or slight to moderate VSP. The patients with severe VSP were divided into two groups. One group included eight patients with severe VSP at proximal sites (the internal carotid artery to the M1 segment), and the other included eight patients with severe VSP extending to the M2 segment and more peripheral sites. The mean CCT of the former group (5.3 s) was significantly different from that of the latter (7.5 s), and the MFV of the former group (128 cm/s) was significantly higher than that of the latter (81 cm/s). The clinical outcomes for the latter patients were more serious than those for the former patients.

CONCLUSION

This study suggests that the MFV at the M1 segment is inadequate for estimation of the severity of VSP extending to vessels more peripheral than the M1 segment. Furthermore, severe VSP extending to more peripheral sites can produce more serious ischemic insults, compared with that localized to basal vessels. Patients with negative TCD results and clinical features suggesting the development of VSP should undergo quantitative investigation of cerebral circulatory parameters, such as the CCT, using intra-arterial digital subtraction angiography.

Prognostic value and determinants of ultraearly angiographic vasospasm after aneurysmal subarachnoid hemorrhage

OBJECTIVE

A small number of patients with aneurysmal subarachnoid hemorrhage have angiographic evidence of cerebral vasospasm within 48 hours of the onset of hemorrhage. The present study analyzes the prognostic value and determinants of this ultraearly angiographic finding.

METHODS

We analyzed prospectively collected data from the placebo-treated group in a multicenter clinical trial conducted at 54 neurosurgical centers in North America. The presence and severity of ultraearly angiographic vasospasm (UEAV) was determined by a blinded review of the admission angiograms. Using logistic regression analysis, we identified independent determinants of UEAV from demographic, clinical, laboratory, and neuroimaging characteristics of the patients. The impact of UEAV on the risk of symptomatic vasospasm and 3-month outcome was analyzed after adjusting for potential confounding factors.

RESULTS

Of 296 patients in the analysis, 37 (13%) had angiographic evidence of vasospasm at admission. An initial Glasgow Coma Scale score of less than 14 (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.1-6.0), and serum sodium greater than 138 mmol/L (OR, 3.4; 95% CI, 1.5-8.3) were associated with UEAV. UEAV was associated with increased risk of symptomatic vasospasm (OR, 2.5; 95% CI, 1.2-5.4) and poor outcome at 3 months (OR, 2.8; 95% CI, 1.2-6.3), after adjusting for other variables. This risk of symptomatic vasospasm was not influenced by early surgery (within 48 h of hemorrhage onset). Poor outcome was more likely to occur in patients with UEAV who did not undergo early surgery (P = 0.03).

CONCLUSION

Our analysis suggests that patients with angiographic evidence of vasospasm at admission are at high risk for both symptomatic vasospasm and poor outcome. We also found that early surgery did not aggravate this risk.

Effect of clot removal and surgical manipulation on regional cerebral blood flow and delayed vasospasm in early aneurysm surgery for subarachnoid hemorrhage

BACKGROUND

Effect of clot removal and surgical manipulation on cerebral blood flow (CBF) and delayed vasospasm was studied in early aneurysm surgery for subarachnoid hemorrhage (SAH).

METHODS

Thirty-two patients in this study fulfilled the following criteria: ruptured anterior communicating aneurysms, computed tomography (CT) within 2 days and unilateral pterional approach within 3 days after the ictus, bilaterally symmetrical clots without intracerebral hematoma, no postoperative complication, and CBF studies with single photon emission computed tomography (SPECT) with 123I-IMP.

RESULTS

Postoperative regional hypoperfusion due to brain retraction was frequently recognized on 123I-IMP-SPECT without infarction. The regional CBF (rCBF) showed a continuous fall during the first 4 weeks after the ictus, followed by improvement. The rCBF in the vicinity of the surgical route was significantly lower, especially in the acute stage (Day 3-7). A significant association between decrease of cisternal blood after surgery and the degree of local vasospasm and local CBF values during spasm stage was observed in the interhemispheric cisterns, A2 and medial frontal cortex, but not in the sylvian fissure or insular cisterns, M1 or M2, and frontal watershed and temporal cortex.

CONCLUSIONS

The present study provides evidence for the effectiveness of direct clot removal by early surgery for SAH on local vasospasm and CBF reduction. However, a potential improvement in local CBF with clot removal could be masked by brain retraction, which was demonstrated to affect rCBF adversely. Therefore, it is critical to perform brain retraction as gently as possible.

Coagulative and fibrinolytic activation in cerebrospinal fluid and plasma after subarachnoid hemorrhage

OBJECTIVE

Intrathecal fibrinolytic therapy has been used as one of the anticerebral vasospasm (VS) preventative therapies in patients with subarachnoid hemorrhage (SAH). However, the changes in coagulation and fibrinolysis in the blood and cerebrospinal fluid (CSF) after SAH remain unknown.

METHODS

Fifty patients with SAH caused by ruptured cerebral aneurysms were studied postoperatively to detect the serial changes of the thrombin-antithrombin III complex, active plasminogen activator inhibitor (PAI)-1, and tissue plasminogen activator (tPA)-PAI complex (tPA-PAI) activities in the plasma and CSF collected from cisternal drainage catheters.

RESULTS

The CSF levels of all parameters and plasma PAI-1 levels were significantly higher in patients with severe SAH than in those with mild SAH. There was no relationship between the CSF and plasma levels of these parameters (except the CSF levels of tPA-PAI) and the initial neurological statuses. The CSF PAI-1 levels increased to greater than 20 ng/ml near the time of the occurrence of cerebral VS, whereas they remained below 20 ng/ml in patients without VS. The CSF tPA-PAI levels showed the highest peak near the time of VS remission. The CSF PAI-1 and tPA-PAI levels were significantly lower in patients with good outcomes than in those with poor outcomes.

CONCLUSION

Both the coagulative and fibrinolytic systems were activated in the CSF and plasma after SAH in correlating to the amount of SAH clot. The intrathecal administration of fibrinolytic agents should be started early after surgery, before CSF PAI-1 levels increase, for patients with severe SAH. Patients with CSF PAI-1 levels greater than 20 ng/ml experienced high incidence of VS and poor outcomes.

Subarachnoid blood on CT and memory dysfunctions in aneurysmal subarachnoid hemorrhage

Ninety patients with a previous subarachnoid haemorrhage (SAH) were given a set of memory tests comprising immediate free recall of words (indexing long-term memory, LTM, and short-term memory, STM), final free recall of words (indexing LTM), final cued recall of words (indexing LTM), and a digit span test (indexing working memory, WM). Patients with a large amount of blood on CT, carried out within 72 h of the bleed, showed LTM as well as STM dysfunction, whereas patients with a small amount of subarachnoid blood evidenced only STM dysfunction. Patients with the ruptured aneurysm located on the anterior cerebral artery, however, constituted an exception with dysfunction of both LTM and STM together with intact WM, independent of the amount of subarachnoid blood. Also, patients with internal carotid artery or middle cerebral artery aneurysms and large volume SAH displayed LTM dysfunction, but differed concerning STM, the former showing intact STM and the latter showing STM dysfunction. Thus, it appears, that the combined information from factors such as the amount of subarachnoid blood and the location of the ruptured aneurysm is of vital importance for explaining the different patterns of memory dysfunctions after SAH.

Transcranial Doppler detection of vertebrobasilar vasospasm following subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Transcranial Doppler sonography is of established value in the detection and monitoring of middle cerebral artery vasospasm. Little information exists on the utility of transcranial Doppler for detection of posterior circulation vasospasm.

METHODS

Cerebral angiography and conventional hand-held transcranial Doppler sonography were compared to determine sensitivity and specificity of transcranial Doppler for detection of vertebral and basilar artery vasospasm.

RESULTS

Of 59 consecutive subarachnoid hemorrhage patients with transcranial Doppler angiogram correlations, 42 underwent posterior circulation angiography to evaluate 64 vertebral arteries and 42 basilar arteries during the period of risk for vasospasm and had technically adequate transcranial Doppler examinations within 24 hours of the angiogram. A mean flow velocity of 60 cm/s and above was indicative of both vertebral and basilar artery vasospasm. For the vertebral artery, there were 7 true-positive test results, 42 true-negatives, 6 false-positives (unknown cause in 3, increased collateral flow in 1, adjacent vessel vasospasm in 1, hyperperfusion in 1), and 9 false-negatives (anatomic in 7, operator error in 2). Sensitivity was 44% and specificity was 87.5%. For the basilar artery, there were 10 true-positives, 23 true-negatives, 6 false-positives (unknown cause in 4, hyperemia/hyperperfusion in 1, increased collateral flow in 1), and 3 false-negatives (operator error in 2, tortuous vessel course in 1). Sensitivity was 76.9% and specificity was 79.3%. When the diagnostic criterion was changed to > or = 80 cm/s (vertebral artery) and > or = 95 cm/s (basilar artery), all false-positive results were eliminated (specificity and positive predictive value, 100%).

CONCLUSIONS

Our data suggest that transcranial Doppler has good specificity for the detection of vertebral artery vasospasm and good sensitivity and specificity for the detection of basilar artery vasospasm. Transcranial Doppler is highly specific (100%) for vertebral and basilar artery vasospasm when flow velocities are > or = 80 and > or = 95 cm/s, respectively.

A statistical analysis of factors related to symptomatic cerebral vasospasm

A retrospective review of patients presenting to our institution with aneurysmal subarachnoid hemorrhage between 1980-1990 was accomplished. Eleven variables were examined as to their relationship to clinical vasospasm: age, sex, clinical grade, amount of subarachnoid blood on CT, aneurysm location, incidence of vasospasm, incidence of complications, use of calcium channel blockers, time to surgery, length of stay, and outcome. Data were analyzed with univariate and multivariate logistical regression methodology. By univariate analysis, age under 20, amount of subarachnoid hemorrhage, and clinical grade were associated with a higher risk of vasospasm. Using multivariate logistic regression, these factors, along with age under 35, were correlated as being predictive of clinical vasospasm. When all patients are grouped into either good or bad outcome, and a similar analysis is performed, only in the poor outcome group is the amount of subarachnoid hemorrhage and clinical grade correlated with vasospasm. This suggests that there is a group of patients with a predisposition to vasospasm that is independent of subarachnoid hemorrhage and clinical grade, and that these patients may have a more favorable outcome.

Vasospasm prevention with postoperative intrathecal thrombolytic therapy: a retrospective comparison of urokinase, tissue plasminogen activator, and cisternal drainage alone

The authors report the results of a retrospective review, between January 1986 and December 1991, of the results of early surgery and intrathecal thrombolytic therapy in 111 patients with aneurysmal subarachnoid hemorrhage. Effects on clot lysis, angiographic and symptomatic vasospasm, cerebral infarction, and clinical outcome were compared in 60 patients treated with urokinase (UK) 60,000 IU/d for 7 days (UK group), 22 patients treated with 0.042 to 1 mg tissue plasminogen activator (tPA) every 6 to 8 hours for 5 days (tPA group), and 29 patients who did not receive treatment with either thrombolytic agent (no-treatment group). The no-treatment group consisted of all patients treated before July 1986 and of patients in whom thrombolytic therapy was attempted but failed to start or in whom the therapy was not used intentionally because of small subarachnoid clot. Treatment with UK was employed between July 1986 and March 1991, and tPA was employed during the remainder of the study for patients at a higher risk for vasospasm. The severity of angiographic vasospasm and the incidence of infarction in the UK and the tPA groups were less than those of the no-treatment group (P < 0.01), in spite of a larger amount of initial subarachnoid blood clot in both thrombolytic groups. This appears to be the result of the more rapid clearance of cisternal clot in the thrombolytic groups than the no-treatment group (P < 0.01). Only tPA therapy reduced the incidence of symptomatic vasospasm (P < 0.05). No serious complications were observed, although in the tPA group, asymptomatic intraventricular hemorrhage occurred in one patient, and transient confusion in another. Both received 4 mg tPA/d. Meningitis was suspected in 16 patients of the UK group. However, in this relatively small retrospective series, there were no differences among the three groups in overall outcome at 3 months. This study indicates that postoperative intrathecal thrombolytic therapies, especially with less than 4 mg/d of tPA, are effective in lysing subarachnoid clot and preventing vasospasm and infarction safely.

"Brain attack": the rationale for treating stroke as a medical emergency

Stroke is the third leading cause of death in the United States, behind only heart disease and cancer. With an estimated three million survivors of stroke in the United States, the cost to society, both directly in health care and indirectly in lost income, is staggering. Despite recent advances in basic and clinical neurosciences, which have the potential to improve the treatment of acute stroke, the general approach to the acute stroke patient remains one of therapeutic nihilism. Most basic science studies show that to be effective, acute intervention to reperfuse ischemic tissue must take place within the first several hours, as is the case with ischemic myocardium. In addition, most neuroprotective agents must also be administered within a short time frame to be effective at salvaging at-risk tissue. Recent studies have suggested that the outcome after intracerebral and subarachnoid hemorrhage is improved with early intervention. However, most stroke patients fail to present to medical attention within this short "window of opportunity." The public's knowledge about stroke is woefully inadequate. However, clinicians who deal with stroke can use the dramatic changes in the treatment of acute myocardial infarction over the last 2 decades as a guide for shaping changes in the management of acute stroke. Comprehensive educational efforts aimed at clinicians and the public at large have dramatically reduced the time from symptom onset to presentation and treatment for acute myocardial infarction, enabling treatment methods such as thrombolysis to be effective. The Decade of the Brain offers a unique opportunity to all concerned with the treatment of the patient with acute stroke to engage in a concerted effort to bring patients with a "brain attack" to specialized neurological attention within the same timeframe that the "heart attack" patient is handled. Such an effort is justified because, although at the present time there are few therapeutic interventions of "proven" value in the treatment of acute stroke, there is more than sufficient suggestive evidence that a number of approaches may be beneficial within the first few hours after the onset of the stroke.

Cerebral vasospasm in elderly patients treated by early operation for ruptured intracranial aneurysms

Cerebral vasospasm in elderly patients was studied under strict criteria. A total of 145 patients, who had been operated on in the acute stage after subarachnoid haemorrhage, were classified into two age groups. Those aged 59 years or younger were in group 1 (76 cases, 52%), and those aged 60 years or older were in group 2 (69 cases, 48%). The severities of both the subarachnoid haemorrhage on computed tomography scan and the angiographic vasospasm were graded from 0 to IV. Close correlations were found in both groups for the angiographic vasospasm grades to the incidences of both symptomatic vasospasm and low-density areas on computed tomography scan. Angiographic vasospasm was observed in 95% of group 1 and in 91% of group 2 patients. The incidences of permanent symptomatic vasospasm were 14% in group 1 and 19% in group 2. Low-density areas on computed tomography occurred in 16% of group 1 and in 17% of group 2. Generally, the higher the clinical grades and/or the higher the subarachnoid haemorrhage grades, the more severe were the vasospasms. These tendencies were more apparent in subarachnoid haemorrhage grading. The mortality rates were 8% in group 1 and 17% in group 2. However, when both the clinical grades and the subarachnoid haemorrhage grades were analyzed, there were no significant differences between groups 1 and 2 in either the severity of vasospasm or in the outcome. It must be concluded that neither the angiographic vasospasm grades nor the incidence of symptomatic vasospasm are significantly effected by age.

A primate model for acute and late cerebral vasospasm: angiographic findings

A subarachnoid haemorrhage (SAH) in the squirrel monkey was produced by injection of blood via a permanently implanted catheter connected to the cisterna magna and a cannula stereotactically inserted into the interpeduncular cistern. Repeated angiographic examinations of the vertebro-basilar and right internal carotid arteries revealed a biphasic vasospasm with a maximal acute spasm at ten minutes and maximal late spasm at six days after blood injection. The present study has shown that a reproducible biphasic vasospasm can be produced in the squirrel monkey and evaluated by repeated angiographic examinations. The model is suitable in the study of basic mechanisms underlying vasospasm in a primate and, due to the size of the animal, autoradiographic evaluation of the cerebral blood flow and metabolism can be performed at an acceptable cost.

Anesthesia for intracranial aneurysm surgery

Aneurysmal rupture represents the most common cause of subarachnoid hemorrhage. Approximately two-thirds of persons who experience a subarachnoid hemorrhage will die or become disabled. Although advances in neurosurgical techniques, neuroanesthetic management, and neuroradiology have resulted in great progress in reducing the operative risk for patients with intracranial aneurysms, the overall outcome following subarachnoid hemorrhage remains disappointing. This article provides an overview of some current concepts related to the perioperative management of patients with intracranial aneurysms, such as the risk and management of rebleeding and vasospasm, and considerations related to the timing of surgery. The anesthetic management of these patients is reviewed, emphasizing principles relating to the facilitation of surgery--by optimizing operative conditions and minimizing the risks of intraoperative aneurysmal rupture or the aggravation of neurologic deficits--and to the provision of a smooth, stable recovery. Despite the disappointing overall prognosis following subarachnoid hemorrhage, adherence to these principles can optimize the outcome for those patients who reach the operating room.

Cerebral blood flow and metabolism following subarachnoid haemorrhage: effect of subarachnoid blood

The amount of effused blood following a subarachnoid haemorrhage (SAH) was estimated in 48 patients by cerebral computerized tomographic scanning. The cerebral oxygen consumption (CMRO2) was calculated as arteriovenous difference for oxygen multiplied by mean cerebral blood flow measured by the 133-Xe inhalation technique. A significant negative correlation was observed between CMRO2 and amount of subarachnoid blood, with additional reduction in CMRO2 in case of ventricular bleeding. Cerebral blood flow on admission, opposed to CMRO2, showed no correlation to amount of blood on CT scan. A correlation was observed for blood flow measured at day 5 and further on, indicating a restored coupling between flow and metabolism. The clinical (Hunt) grade on admission and the outcome correlated to the amount of blood. These observations suggest that the acute reduction in CMRO2 following a SAH is mainly determined by the amount of blood escaping during the aneurysm rupture, and that the cerebral blood flow level a few days after SAH mainly is determined by the initial reduction in oxygen uptake.

Value of electroencephalogram in prediction and diagnosis of vasospasm after intracranial aneurysm rupture

The Electroencephalogram (EEG) of 151 patients whose ruptured aneurysm was confirmed by CT scan and angiography was recorded on the first day (D1) and the fifth day (D5). On D1, EEG had a prognostic value: among 46 patients with normal EEG, 72% presented neither further electrical ischaemic features nor delayed angiographic vasospasm; on the other hand, when bilateral bursts of slow waves, "axial bursts" or slow delta waves were recorded (78 cases), 97% exhibited EEG signs of ischaemia and angiographic vasospasm a few days later. These data were clearly related to the importance of the haemorrhage, specially when thick clots in the subarachnoid cisterns were found on the CT scan. On D5, EEG had a diagnostic value: focal or asymetrical bilateral delta waves occurring at that date seemed to correspond to ischaemia; among 107 patients with these electrical features, an angiographic vasospasm appeared in 96% of cases, and the importance of electrical abnormalities could be related to the degree of arterial narrowing. We conclude that EEG data are very useful in prediction as well in recognition of post-subarachnoid haemorrhage ischaemia due to vasospasm and are sufficiently precise to postpone control angiography and operation, when delayed surgery is programmed.

Grading the amount of blood on computed tomograms after subarachnoid hemorrhage

According to several studies, the amount of subarachnoid blood on the initial computed tomogram of patients with aneurysmal subarachnoid hemorrhage has predictive value with respect to infarction and outcome. Of several methods for assessing the amount of subarachnoid blood, none has been subjected to a study of interobserver agreement. We describe our own method, applied in previous studies, in which the amounts of blood in 10 basal cisterns and fissures and in four ventricles are graded separately. In grading single computed tomograms of 182 consecutive patients with subarachnoid hemorrhage, the agreement between pairs of three observers, studied with kappa statistics, was relatively good for individual cisterns or fissures (kappa between 0.35 and 0.65) and ventricles (kappa between 0.47 and 0.74). The Spearman rank correlation coefficients for the sum of the scores for subarachnoid and intraventricular blood were very high. Summed scores for extravasated blood are suitable as a baseline variable in follow-up studies of patients with subarachnoid hemorrhage.

The International Cooperative Study on the Timing of Aneurysm Surgery. Part 1: Overall management results

The International Cooperative Study on the Timing of Aneurysm Surgery evaluated the results of surgical and medical management in 3521 patients between December, 1980, and July, 1983. At admission, 75% of patients were in good neurological condition and surgery was performed in 83%. At the 6-month evaluation, 26% of the patients had died and 58% exhibited a complete recovery. Vasospasm and rebleeding were the leading causes of morbidity and mortality in addition to the initial bleed. Predictors for mortality included the patient's decreased level of consciousness and increased age, thickness of the subarachnoid hemorrhage clot on computerized tomography, elevated blood pressure, preexisting medical illnesses, and basilar aneurysms. The results presented here document the status of management in the 1980's.

Effect of early operation on cerebral vasospasm

The effect of early operation on cerebral vasospasm was studied in 150 patients with aneurysmal subarachnoid hemorrhages who fulfilled all of the following criteria: admission by day 2 after subarachnoid hemorrhage, no rebleeding, clinical grades I to IV on admission, subarachnoid hemorrhage alone on computed tomography scan, not operated on between days 4 and 20, and availability of bilateral carotid angiograms done by day 2 and redone between days 7 and 9. The patients were divided into two groups: those operated on by day 3 (group 1: 116 patients) and those operated on after day 20 or not operated on (group 2: 34 patients). Severity of both subarachnoid hemorrhage on computed tomography scan and angiographic vasospasm were graded into 0-IV. Angiographic vasospasm was observed in 95% of group 1 and in 88% of group 2 patients. A significant difference could not be found between groups 1 and 2 in the angiographic vasospasm grades. The incidence of symptomatic vasospasm in group 1 was 18%, which was significantly lower than the 44% in group 2. In group 1 patients with subarachnoid hemorrhage grades II to III, the incidences of symptomatic vasospasm and low density area on computed tomography scan were 13% and 10%, respectively. Both of these rates were significantly lower than those in group 2, which were 50% and 36%, respectively. However, in patients with subarachnoid hemorrhage grade IV, no differences could be found between groups 1 and 2. There was a close correlation between the angiographic vasospasm grades and the incidence of symptomatic vasospasm in group 1. However, in group 1, no correlation could be observed between the site of ruptured aneurysms or the timing of operations and vasospasm. Although there is still a limit to the effect of early operation on cerebral vasospasm in patients with subarachnoid hemorrhage grade IV, symptomatic vasospasm after subarachnoid hemorrhage may be ameliorated by early operation in patients with subarachnoid hemorrhage grades II to III.

Effect of clot removal on cerebral vasospasm

The effect of clot removal on cerebral vasospasm was studied in 104 patients with aneurysmal subarachnoid hemorrhage (SAH). The series included patients who fulfilled all of the following criteria: operation was performed by Day 3 after the ictus; the patient's preoperative clinical grade was between Grades I and IV; there was no rebleeding; computerized tomography (CT) showed only SAH; and carotid angiograms were performed by Day 2 and repeated between Days 7 and 9. Both the degree of SAH on CT and angiographic vasospasm were graded from 0 to III. The relationship of the SAH grade in the basal frontal interhemispheric fissure (IHF) to the presence of vasospasm at the A2 segments of the anterior cerebral artery and the relationship of the SAH grade in the sylvian stems to the presence of vasospasm at the M1 segments of the middle cerebral artery were analyzed. Correlation of preoperative and postoperative SAH grades with the angiographic vasospasm grades, with the incidence of symptomatic vasospasm, and with the low-density area on CT could be found in the A2 and M1 territories. Decrease of cisternal blood measured by CT after the operation did not relate directly to the reduction of vasospasm. When the SAH was Grade II or III in the basal frontal IHF, the angiographic vasospasm grades at the A2 were significantly lower in patients with surgery via the interhemispheric approach than in those with surgery via the pterional approach. Symptomatic vasospasm occurred in two of the eight cases operated on by the interhemispheric approach compared with 11 of the 22 cases approached via the pterional route. In patients with a pterional approach, there was no significant difference in severity of vasospasm in the M1 territory between the side of approach and the opposite side. No consistent relationship could be found between the time interval from SAH to operation and the severity of vasospasm. While clot removal may ameliorate cerebral vasospasm, its effect per se does not seem to be significant.

Risk factors in intracranial saccular aneurysms. Aspects on the formation and rupture of aneurysms, and development of cerebral vasospasm

Intracranial saccular aneurysms have been a well-known clinical and pathological entity for over two centuries. The pathophysiological events that lead to aneurysm formation and rupture are, however, poorly understood. Besides an HLA-associated genetic factor, the most widely accepted risk factors are arterial hypertension, female gender, and increasing age. Some aneurysm patients have a deficient formation of Type III collagen. This seems to interfere with the mechanical integrity of the cerebral arterial wall encouraging aneurysm formation. While some of the risk factors may be involved in the process of aneurysm formation, others may be of importance in the actual aneurysm rupture. Medical and surgical developments have only had a slight impact on mortality rates from aneurysm rupture. The principal cause of death and disability is cerebral arterial spasm. Considerable effort has been expended in investigating the etiology of this phenomenon. Previous studies have failed to yield conclusive evidence of the causative agent(s) or the nature of cerebral artery narrowing. The time course of vasospasm after the onset of subarachnoid hemorrhage is consistent with an immune-mediated response, and more recent observations suggest that immunological processes including activation of the complement system may be involved. Missed minor bleeding episodes may thus be a risk factor for aneurysm patients in respect to the development of cerebral vasospasm.

Subarachnoid haemorrhage of unknown origin: clinical and tomographical aspects

65 patients with negative but technically satisfactory 4 vessel angiography - all admitted to our Department in the years 1976-1983 - were evaluated in the present study. CT scan was undertaken in all cases (in 47 cases within 4 days of haemorrhage). Arterial hypertension was present on admission in 9% of cases. The period of follow-up ranged from 4 to 11 years, with a mean of 5.3 years. The study group was compared to a control group, comprising 760 patients with subarachnoid haemorrhage from ruptured aneurysms, admitted during the same period. Clinical grade on admission (Hunt's classification) was better in patients belonging to the study group. The amount of cisternal deposition on CT scan was less significant than in patients with ruptured aneurysms, and the deposition was often atypical (circumpeduncular, ambiental, and/or tentorial). Clinical deterioration associated with vasospasm was observed in 5% of patients in this study and in 27% of patients in the control group. In patients with a consistent or thick cisternal layer (CT scan "at risk") the incidence of clinical vasospasm was 21%, against 47% in controls. One or more rebleedings occurred in 12% of patients in the study group, against 25% of patients in the control group. A significant ventricular dilatation was observed in 15% of patients in the first group (requiring a shunt in 8%), against 25% of patients in the second group (requiring a shunt in 11%). Final outcome was favourable in 95% of patients in this study group and in 63% of patients in the control group, with a mortality rate of 5% in the first group and 32% in the second group.

Effect of cisternal drainage after early operation for ruptured intracranial aneurysms

The effect of postoperative cisternal drainage was assessed in 132 patients who underwent early surgery for ruptured aneurysms. Although the incidence of both cerebral vasospasm and mortality was low in the patients who had cisternal drainage, the incidence of hydrocephalus was significantly higher in these patients. Drainage has been recommended as a useful procedure because it has been shown to improve the prognosis through prophylaxis and relief of vasospasm and removal of blood-contaminated cerebrospinal fluid. However, the results of this study indicate that extensive cerebrospinal fluid drainage may lead to hydrocephalus, which can be controlled by regulation of the drainage outflow and pressure.

Rebleeding, ischaemia and hydrocephalus following anti-fibrinolytic treatment for ruptured cerebral aneurysms: a retrospective clinical study

350 patients with subarachnoid haemorrhage from aneurysmal rupture--admitted in the years 1966-1983--were selected for a retrospective controlled study on the efficacy of antifibrinolytic therapy (AFT). Patients treated with antifibrinolytics were divided into two groups, according to the day of hospital admission and onset of therapy, respectively between 0 and 3 days (SG 1) and between 4 and 7 days from SAH (SG 2); treated patients (260 cases) received i.v. tranexamic acid (6 gr/day) for at least two weeks. Patients admitted before 1974, not receiving antifibrinolytics (90 cases), were selected as controls and divided into two groups (CG 1 and CG 2), according to the day of admission. In the first study group (admission 0-3 days) the rebleeding rate within 2 weeks was 9% versus 23% in controls (p less than 0.01). The incidence of rebleeding within 3 and 4 weeks was also significantly lower (p less than 0.05) than in controls. No significant difference was observed in the rebleeding rate in treated and untreated patients with late admission (4-7 days). Mortality from rebleeding was 16% in the first study group versus 17% in controls; in the second study group the figure was 6% versus 8% in controls. Seventy-five cases of ischaemic disorders (29%) were registered in treated patients versus 13 cases in controls (14%; p less than 0.01). Thirty-seven patients receiving AFT (14%) developed significant ventricular dilatation requiring shunt insertion, versus one patient in the control groups (1%; p less than 0.001). Final outcome was similar in the 4 groups. In conclusion--according to our data--AFT modifies the behaviour of rebleeding and the patients' course, although it does not modify the outcome after SAH. Clinical use of antifibrinolytic therapy appears still justified in those patients who cannot be operated on in the acute stage after SAH, provided that an associated anti-ischaemic therapy is undertaken.

Haem derivatives in subdural haematomas

The oxyhaemoglobin, methaemoglobin and bilirubin concentrations were determined in subdural haematomas and cerebrospinal fluid from 18 patients. The total haem derivative concentration ranged from 55 mumol/l to 13.9 mmol/l in the haematomas and from 0.1 mumol/l to 8.2 mumol/l in the cerebrospinal fluid. Bilirubin was the dominating fraction in haematomas with haem derivative concentrations lower than 1 mmol/l. For haematomas exceeding this value, the bilirubin transforming capacity seemed to have reached a maximum. More of the oxyhaemoglobin was oxidized to methaemoglobin in these cases, a reaction known to release superoxide radicals. The possible pathophysiological significance hereof, e.g. in cerebral vasospasm, is discussed.

Nimodipine treatment of selected good-risk patients with subarachnoid hemorrhage: no significant difference between present and historical results

Eighty-four patients were treated early with nimodipine intravenously, and thereafter orally, up to 21 days after aneurysmal subarachnoid hemorrhage. Thirty-nine patients in the nimodipine-treated group were carefully selected to be compared with similar patients from a historical control group (114 patients) conventionally treated. The causes of poor results were clinically identified as follows: delayed ischemic deterioration (DID), rebleeding, complications of surgery, or not defined. There was no significant difference in the distribution of DID or outcome at follow-up examination (at least 6 months later) between the nimodipine-treated group and the control group.

Timing of aneurysm surgery. Comparison of results of early and delayed surgical intervention

In a retrospective study covering a period of 8 years and 403 surgically treated patients the results of microsurgical aneurysm treatment were compared between two groups. One group received surgical treatment within 72 h and the second were treated surgically after this time interval. The data indicated that patients receiving delayed surgery had a better outcome at 6 months as compared to patients receiving immediate surgical intervention. The location of the aneurysm and the preoperative neurological status imparted the most significant impact on the subsequent outcome and on the incidence of rebleeding. High risk patients with poor neurological status on admission seemed to have a considerable chance of gaining satisfactory functional recovery, especially with a more delayed surgical approach. Despite its superior results delayed surgery was burdened with a rebleeding rate and an incidence of ischemic deficits due to cerebral vasospasm twice as high as in patients receiving early surgery. The implications of these results on surgical timing are discussed and it is concluded that despite the fact that late surgery yields better results than early surgery, the considerable reduction of recurrent hemorrhage and additional possibility of aggressive treatment of incipient vasospasm makes early surgery a promising alternative for the treatment of patients with aneurysmal subarachnoid hemorrhage.

Spontaneous subarachnoid haemorrhage: expert system for appraisal of the prognosis and computer-supported decision for therapy

An expert system is presented which allows appraisal of the prognosis and a computer-supported decision for the therapy of patients with acute spontaneous subarachnoid haemorrhage (SAH). The knowledge of physicians as a synthesis of their own and other clinicians' experience is simulated with methods of artificial intelligence by setting up two data banks. In one data bank, selected information on the correlation between initial clinical parameters, on the one hand, and mortality, outcome and complications, on the other, from about 250 neurological publications is stored, taking into consideration the therapeutic regimens applied. A second data bank receives clinical and laboratory data profiles of a patient population which has already been treated. The expert system is able to compare the individual initial findings with the corresponding parameter combination stored in the data banks regarding the decision for therapy of a patient to be treated. This enables both calculation of the probable complications and prediction of the expected outcome in relation to various possible forms of therapy. The expert system can thus indicate the kind of therapy where the lowest number of complications and the best outcome can be expected, thus supporting the decision of the physician. As each new patient is treated, the volume of stored information increases, so the system possesses self-learning characteristics. To check the validity of the prognoses, the outcome estimated by the expert system for 51 patients with spontaneous SAH was compared with the actual outcome, and a high level of agreement was attained.

Clinical vasospasm after subarachnoid hemorrhage: response to hypervolemic hemodilution and arterial hypertension

Delayed neurologic deterioration from vasospasm remains the greatest cause of morbidity and mortality following subarachnoid hemorrhage. The authors assess the incidence and clinical course of symptomatic vasospasm following subarachnoid hemorrhage using a uniform management protocol over a 24-month period. One hundred eighteen consecutive patients were admitted to the neurovascular surgery service within 2 weeks of subarachnoid hemorrhage not attributed to trauma, tumor, or vascular malformation (113 patients had aneurysms). Early surgery was performed whenever possible, and hypertensive hypervolemic hemodilution therapy was instituted at the first sign of clinical vasospasm. Forty-two patients (35.6%) developed characteristic signs and symptoms of clinical vasospasm with angiographic verification of spasm in 39 cases. All patients with clinical vasospasm received hypervolemic hemodilution therapy aiming for a hematocrit of 33-38%, a central venous pressure of 10-12 mm Hg (or a pulmonary wedge pressure of 15-18 mm Hg), and a systolic arterial pressure of 160-200 mm Hg (120-150 mm Hg for unclipped aneurysms) for the duration of clinical vasospasm. Over the course of treatment, 60% of patients with clinical vasospasm had sustained improvement by at least 1 neurologic grade, 24% maintained a stable neurologic status, and 16% continued to worsen. At the end of hypervolemic hemodilution therapy, 47.6% had become neurologically normal, 33.3% had a minor neurologic deficit, and 19% had a major neurologic deficit or were dead. There were 3 instances of cardiopulmonary deterioration (7%), all of which were in patients without Swan-Ganz catheters, and all resolved with appropriate diuresis. One patient rebled and died while on hypervolemic hemodilution therapy.(ABSTRACT TRUNCATED AT 250 WORDS)