A Comparative Classification Analysis of Abdominal Aortic Aneurysms by Machine Learning Algorithms

The objective of this work was to perform image-based classification of abdominal aortic aneurysms (AAA) based on their demographic, geometric, and biomechanical attributes. We retrospectively reviewed existing demographics and abdominal computed tomography angiography images of 100 asymptomatic and 50 symptomatic AAA patients who received an elective or emergent repair, respectively, within 1-6 months of their last follow up. An in-house script developed within the MATLAB computational platform was used to segment the clinical images, calculate 53 descriptors of AAA geometry, and generate volume meshes suitable for finite element analysis (FEA). Using a third party FEA solver, four biomechanical markers were calculated from the wall stress distributions. Eight machine learning algorithms (MLA) were used to develop classification models based on the discriminatory potential of the demographic, geometric, and biomechanical variables. The overall classification performance of the algorithms was assessed by the accuracy, area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and precision of their predictions. The generalized additive model (GAM) was found to have the highest accuracy (87%), AUC (89%), and sensitivity (78%), and the third highest specificity (92%), in classifying the individual AAA as either asymptomatic or symptomatic. The k-nearest neighbor classifier yielded the highest specificity (96%). GAM used seven markers (six geometric and one biomechanical) to develop the classifier. The maximum transverse dimension, the average wall thickness at the maximum diameter, and the spatially averaged wall stress were found to be the most influential markers in the classification analysis. A second classification analysis revealed that using maximum diameter alone results in a lower accuracy (79%) than using GAM with seven geometric and biomechanical markers. We infer from these results that biomechanical and geometric measures by themselves are not sufficient to discriminate adequately between population samples of asymptomatic and symptomatic AAA, whereas MLA offer a statistical approach to stratification of rupture risk by combining demographic, geometric, and biomechanical attributes of patient-specific AAA.

Endovascular treatment of an intracranial aneurysm with a ruptured bleb

OBJECTIVE

To study the features and approaches of endovascular treatment for intracranial aneurysms with a ruptured bleb.

METHODS

This retrospective study was carried out from June 2007 to June 2009 in Jilin University, Jilin, China. Thirty patients with intracranial aneurysms with ruptured blebs were included. The aneurysms were diagnosed by digital subtraction angiography (DSA), and the endovascular treatment was planned according to the relationship between the aneurysm body and the ruptured bleb. The aneurysms were classified into 4 types (type I, II, III, IV) based on the size of the neck of the aneurysm connected with the parent artery, the size of the body of the aneurysm, and the size of the junction formed between the aneurysm and bleb. Endovascular treatment for each type of aneurysm was performed.

RESULTS

Type IV aneurysms were the most difficult operation performed, easily resulting in rupture and bleeding during surgery, whereas embolization of a type III aneurysm was relatively simple. Type I and II aneurysms resulted in better prognosis. Statistical analysis showed that the outcome of the treatment of type I and II aneurysms was better than that in type III and IV aneurysms, the outcome of type I, II, and III was better than that in type IV.

CONCLUSION

The outcome of the endovascular treatment of an intracranial aneurysm with a ruptured bleb was related to the aneurysm type. Treatment in a type-dependent manner is therefore recommended.

Endovascular treatment of an intracranial aneurysm with a ruptured bleb

OBJECTIVE

To study the features and approaches of endovascular treatment for intracranial aneurysms with a ruptured bleb.

METHODS

This retrospective study was carried out from June 2007 to June 2009 in Jilin University, Jilin, China. Thirty patients with intracranial aneurysms with ruptured blebs were included. The aneurysms were diagnosed by digital subtraction angiography (DSA), and the endovascular treatment was planned according to the relationship between the aneurysm body and the ruptured bleb. The aneurysms were classified into 4 types (type I, II, III, IV) based on the size of the neck of the aneurysm connected with the parent artery, the size of the body of the aneurysm, and the size of the junction formed between the aneurysm and bleb. Endovascular treatment for each type of aneurysm was performed.

RESULTS

Type IV aneurysms were the most difficult operation performed, easily resulting in rupture and bleeding during surgery, whereas embolization of a type III aneurysm was relatively simple. Type I and II aneurysms resulted in better prognosis. Statistical analysis showed that the outcome of the treatment of type I and II aneurysms was better than that in type III and IV aneurysms, the outcome of type I, II, and III was better than that in type IV.

CONCLUSION

The outcome of the endovascular treatment of an intracranial aneurysm with a ruptured bleb was related to the aneurysm type. Treatment in a type-dependent manner is therefore recommended.

A proposed parent vessel geometry-based categorization of saccular intracranial aneurysms: computational flow dynamics analysis of the risk factors for lesion rupture

OBJECT

The authors created a simple, broadly applicable classification of saccular intracranial aneurysms into three categories: sidewall (SW), sidewall with branching vessel (SWBV), and endwall (EW) according to the angiographically documented patterns of their parent arteries. Using computational flow dynamics analysis (CFDA) of simple models representing the three aneurysm categories, the authors analyzed geometry-related risk factors such as neck width, parent artery curvature, and angulation of the branching vessels.

METHODS

The authors performed CFDAs of 68 aneurysmal geometric formations documented on angiograms that had been obtained in patients with 45 ruptured and 23 unruptured lesions. In successfully studied CFDA cases, the wall shear stress, blood velocity, and pressure maps were examined and correlated with aneurysm rupture points. Statistical analysis of the cases involving aneurysm rupture revealed a statistically significant correlation between aneurysm depth and both neck size (p < 0.0001) and caliber of draining arteries (p < 0.0001). Wider-necked aneurysms or those with wider-caliber draining vessels were found to be high-flow lesions that tended to rupture at larger sizes. Smaller-necked aneurysms or those with smaller-caliber draining vessels were found to be low-flow lesions that tended to rupture at smaller sizes. The incidence of ruptured aneurysms with an aspect ratio (depth/neck) exceeding 1.6 was 100% in the SW and SWBV categories, whereas the incidence was only 28.75% for the EW aneurysms.

CONCLUSIONS

The application of standardized categories enables the comparison of results for various aneurysms' geometric formations, thus assisting in their management. The proposed classification system may provide a promising means of understanding the natural history of saccular intracranial aneurysms.

Characterization of cerebral aneurysms for assessing risk of rupture by using patient-specific computational hemodynamics models

BACKGROUND AND PURPOSE

Hemodynamic factors are thought to play an important role in the initiation, growth, and rupture of cerebral aneurysms. This report describes a pilot clinical study of the association between intra-aneurysmal hemodynamic characteristics from computational fluid dynamic models and the rupture of cerebral aneurysms.

METHODS

A total of 62 patient-specific models of cerebral aneurysms were constructed from 3D angiography images. Computational fluid dynamics simulations were performed under pulsatile flow conditions measured on a normal subject. The aneurysms were classified into different categories, depending on the complexity and stability of the flow pattern, the location and size of the flow impingement region, and the size of the inflow jet. The 62 models consisted of 25 ruptured and 34 unruptured aneurysms and 3 cases with unknown histories of hemorrhage. The hemodynamic features were analyzed for associations with history of rupture.

RESULTS

A large variety of flow patterns was observed: 72% of ruptured aneurysms had complex or unstable flow patterns, 80% had small impingement regions, and 76% had small jet sizes. By contrast, unruptured aneurysms accounted for 73%, 82%, and 75% of aneurysms with simple stable flow patterns, large impingement regions, and large jet sizes, respectively. Aneurysms with small impingement sizes were 6.3 times more likely to have experienced rupture than those with large impingement sizes (P = .01).

CONCLUSIONS

Image-based patient-specific numeric models can be constructed in an efficient manner that allows clinical studies of intra-aneurysmal hemodynamics. A simple flow characterization system was proposed, and interesting trends in the association between hemodynamic features and aneurysmal rupture were found. Simple stable patterns, large impingement regions, and jet sizes were more commonly seen with unruptured aneurysms. By contrast, ruptured aneurysms were more likely to have disturbed flow patterns, small impingement regions, and narrow jets.

Staged bilateral vertebral artery occlusion for ruptured dissecting aneurysms of the basilar artery: a report of 2 cases

BACKGROUND

Dissecting aneurysm of the basillary artery BA is rare. Although mortality rate is high, management remains controversial. We report 2 cases of dissecting aneurysm of the BA presenting with subarachnoid hemorrhage (SAH), both of which were successfully treated using staged occlusion of bilateral vertebral arteries (VAs).

CASE DESCRIPTION

A 64-year-old man and a 34-year-old woman presented with SAH associated with ruptured dissecting aneurysm of the BA. After endovascular occlusion of a single VA, blood flow in the dissected lumen was reduced. However, one aneurysm rebled and the bleb of the other did not change. Vertebral arteries were also occluded using endovascular techniques at 4 and 2 weeks after initial treatment, respectively. On the second intervention, stump pressure ratios of VAs intended for occlusion were 62.5% and 50.6%, respectively. The patients tolerated temporary occlusion of bilateral VAs well. Subsequent permanent occlusion of bilateral VAs resulted in no neurological complication. Complete obliteration of the aneurysmal lumen was demonstrated on magnetic resonance angiography performed 72 and 5 months later, respectively.

CONCLUSION

Staged bilateral VA occlusion might be the last recourse to prevent further hemorrhage from BA dissecting aneurysm. The technique can be safely applied when the stump pressure ratio is 50.6% or greater and when the patient tolerates temporary occlusion, which suggests the existence of sufficient collateral flow from the anterior circulation.

ISAT and ISUIA: The Impact on Informed Consent

The International Subarachnoid Aneurysm Trial (ISAT) was a multicenter randomized trial that compared the safety and efficacy of endovascular coil treatment versus surgical clipping for the treatment of ruptured brain aneurysms. To be eligible for enrollment in the ISAT trial, each patient had to be deemed equally suitable for either coiling or clipping. The investigators used the term "clinical equipoise" to describe this balance. This study more than any other has set the playing field for the future of interventional radiology/endovascular neurosurgery politics.

Anterior and non-anterior ruptured aneurysms: Memory and frontal lobe function performance following coiling

Our aim was to compare memory and frontal function performance between two groups of patients treated with Guglielmi detachable coil (GDC) following intracranial ruptured aneurysm. The subgroups drawn following the localization of the aneurysm consisted of 19 patients presenting with anterior communicating artery aneurysms and 16 patients exhibiting middle cerebral artery and posterior communicating artery aneurysms. The 35 patients and 35 normal controls were administered extensive neuropsychological assessment. Additionally, a scale of qualitative changes of mood was presented to the patients and patients' relatives. The patients showed a better general performance on memory compared with the executive function performance, which was similarly impaired in both groups. We suggest that executive functions are more vulnerable to differently located lesions than memory functions.

Grading of subarachnoid hemorrhage: modification of the world World Federation of Neurosurgical Societies scale on the basis of data for a large series of patients

OBJECTIVE

The goals of this study were to use a large, prospectively collected, multicenter database for patients with aneurysmal subarachnoid hemorrhage (SAH) who were treated between 1991 and 1997 to determine the prognostic significance of clinical and radiological factors for outcomes and to use those factors to develop a grading scale to predict outcomes.

METHODS

A total of 3567 patients with SAH who were entered into four randomized clinical trials of tirilazad were studied. Outcomes were assessed 3 months after SAH, with the Glasgow Outcome Scale. Twenty clinical and radiological factors were entered into univariate and multivariate analyses, to determine factors prognostic for outcomes. Grading scales based on the most powerful prognostic parameters were statistically derived and validated and were compared with the World Federation of Neurosurgical Societies (WFNS) grading scale.

RESULTS

Factors predictive of outcomes included age, WFNS grade, history of hypertension, systolic blood pressure at admission, ruptured aneurysm location and size, blood clot thickness on computed tomographic scans, and angiographic vasospasm at admission. A grading scale using these factors could be derived; it predicted outcomes more accurately than did the WFNS scale, although it would be more complex to use.

CONCLUSION

Outcome prediction after SAH can be improved by adding additional clinical and radiological factors to the WFNS scale, albeit with added complexity.

Endovascular repair of abdominal aortic aneurysms: device-specific outcome

OBJECTIVES

Endovascular repair of abdominal aortic aneurysms, while advantageous because of its minimally invasive nature, falls short of achieving the long-term durability of traditional open surgical repair. Problems such as device migration, continued sac pressurization from endoleak, and graft limb thrombosis culminate in a high rate of secondary procedures and failure to protect against aneurysm rupture. While prior studies hint at a correlation between these postprocedural events and specific device design, a single comparative analysis that correlates device attributes with clinical outcome has not been performed.

METHODS

Over 6 years ending in 2002, 703 patients underwent endovascular treatment of infrarenal abdominal aortic aneurysms. During this time, five devices were used, ie, Ancure, AneuRx, Excluder, Talent, and Zenith, and six device-specific groups were analyzed; the Zenith group was subdivided into those placed as part of the multicenter trial (Zenith-MCT) and those under a sponsor-investigator investigational device exemption trial (Zenith-SIT). Results were assessed with the Kaplan-Meier method for censored data, and the log-rank test was used to ascertain differences between device groups.

RESULTS

While overall survival was diminished in the Zenith-SIT group (P =.046), risk for aneurysm-related death was similar in all groups (P =.336), averaging 2% or less at 12 months. Among the total cohort of patients, freedom from rupture was 98.7% +/- 0.9% at 24 months, without demonstrable differences between groups (P =.533). There were no statistically significant differences in rate of secondary procedures, conversion to open repair, or migration. There were, however, significant differences in risk for graft limb occlusion and rate of endoleak between groups. Limb occlusion occurred most often with Ancure devices (11% +/- 4.6% at 12 months, P =.009). Endoleak of any type was most common with Excluder devices (64% +/- 11% at 12 months, P =.003), a finding directly related to increased frequency of type II leaks in that group (58% +/- 11% at 12 months, P =.001). While there were no differences in frequency of type I or type III endoleak, a trend toward increased risk for microleak was observed with AneuRx devices (4.0% +/- 1.3%, P =.054), and more modular separations were observed with Zenith devices (3.5% +/- 2.3%, P =.032). Shrinkage at 12 months correlated with frequency of endoleak in the device groups, and was most common in the two Zenith groups (54% +/- 7.3% in the Zenith-MCT group and 56% +/- 7.8% in the Zenith-SIT group) and the Talent group (52% +/- 9.7%) and was least in the Excluder group (15% +/- 7.9% at 12 months, P <.001). By contrast, sac growth occurred most often in the Zenith-SIT group (13% +/- 4.5% at 12 months, P =.034), possibly as a result of the challenging aortoiliac anatomy frequently present in these patients.

CONCLUSIONS

There are significant differences in frequency of limb occlusion and endoleak between groups with different endovascular devices. Knowledge of these and other differences is instructional in development of next-generation endovascular devices, incorporating design features linked to satisfactory outcome while abandoning those associated with device failure.

Importance of prospective studies for deciding on a therapeutic guideline for unruptured cerebral aneurysm

(1) In a town of 100,000 population, a 2% incidence rate of unruptured cerebral aneurysm means 2,000 patients. (2) In a town of 100,000 population, the annual occurrence of subarachnoid hemorrhage is 20. (3) The turnover of patients with unruptured cerebral aneurysm is for the 50-year cycle of patients at age from 30 to 80. On the basis of these data, in a town of 100,000 population the number of unruptured cerebral aneurysm cases and of subarachnoid hemorrhage cases occurring in 50 years are 2,000 and 1,000, respectively. In total 3,000 patients with unruptured and ruptured cerebral aneurysm, the distribution of these patients for different sizes of aneurysm can be estimated. We examined the rupture rate for each size of aneurysm. And we found that some of the aneurysm smaller than 10 mm in size rupture soon after their formation and that some of aneurysm of size remain unchanged.

Is the rupture of cerebral berry aneurysms influenced by the perianeurysmal environment?

PURPOSE

To evaluate contact between cerebral berry aneurysms and the perianeurysmal environment and to study the influence this contact has on aneurysm rupture.

MATERIALS AND METHODS

In a series of 76 consecutive patients, pre- and post-contrast CT images of 87 aneurysms were evaluated. Aneurysm locations were identified and aneurysms were divided into two different groups depending on whether they had ruptured or not. Contact between aneurysms and the perianeurysmal environment was studied when present, and considered to be balanced or unbalanced according to symmetry of contact and type of contact interface, i.e. with bone, dura, etc.

RESULTS

Rupture occurred in 47 aneurysms at an average maximum dome size of 7.4 mm. There was contact with elements of the perianeurysmal environment in 38 (81%) of ruptured cases and no evidence of contact in 7 (15%). The nature of contact was unclear in 2 (4%) ruptured aneurysms. In the aneurysms with contact, the nature of contact was unbalanced in 34 (72%) and balanced in 4 (9%). Unbalanced aneurysms ruptured at significantly smaller sizes (average: 7.7 mm) than balanced aneurysms (average: 11.4 mm). Seven aneurysms of small size (3.3-6.9 mm, average: 4.8 mm) were found to have ruptured, despite the fact that they were too small to exhibit contact with the perianeurysmal environment. In 40 unruptured aneurysms (average size: 6.3 mm), contact with the perianeurysmal environment was found in 15 aneurysms, for which balanced contact was found in 11 (27.5%) and unbalanced contact in 4 (10%), and no contact in 25 (62.5%). The average size of the aneurysms without contact (3.7 mm) was significantly smaller than that with balanced contact (10.3 mm) or with unbalanced contact (11.3 mm).

CONCLUSION

Aneurysms exhibit contact with their perianeurysmal environment as soon as they reach a size that exceeds their allowance given by the local subarachnoid space. The contact with the environment was found to be an additional determinant parameter in the evolution of cerebral berry aneurysms and their risk to rupture.

Aneurysmal subarachnoid hemorrhage in patients with Hunt and Hess grade 4 or 5: treatment using the Guglielmi detachable coil system

BACKGROUND AND PURPOSE

Patients in poor clinical condition (Hunt and Hess grade 4 or 5) after subarachnoid hemorrhage (SAH) have historically fared poorly and many often were excluded from aggressive treatment. Early aggressive surgical treatment of SAH can produce good-quality survival for a higher percentage of patients than previously reported. We assessed the outcome of patients with Hunt and Hess grade 4 or 5 who were treated with Guglielmi detachable coil (GDC) embolization.

METHODS

We retrospectively evaluated the records of 27 consecutive grade 4 and 5 patients with 29 aneurysms treated within 72 hours of SAH by using GDCs. Percentage aneurysm occlusion after embolization, perioperative complications, and symptoms of vasospasm were evaluated. Outcome was assessed with the Glasgow Outcome Scale.

RESULTS

Sixteen patients (59%) were grade 4, and 11 (41%) were grade 5. Eighteen (67%) had one aneurysm, six (22%) had two aneurysms, and three (11%) had three aneurysms. Twenty-nine aneurysms were treated. Fourteen (48%) were completely occluded, and four (14%) were nearly completely occluded (>/=95% occlusion) at embolization. Eleven aneurysms (38%) had partial coiling (<95% occlusion). In the 27 patients, one technical (4%) and one clinical (4%) complication occurred at embolization. No rehemorrhage occurred in any patients (follow-up, 6-44 months; mean, 23 months). Twenty-five (92%) had vasospasm, and seven required endovascular treatment because of worsening clinical status. Sixteen patients (59%) died within 30 days of SAH. Eight patients (30%) had a good clinical outcome at a mean follow-up of 23 months.

CONCLUSION

Patients with Hunt and Hess grade 4 or 5 after SAH can undergo successful coil embolization of the aneurysms despite their poor medical condition and a high frequency of vasospasm at the time of treatment. Morbidity and mortality rates with this disease are still high. These findings compare favorably with those published in surgical series for aggressively treated patients with Hunt and Hess grade 4 or 5.

Detection and characterization of very small cerebral aneurysms by using 2D and 3D helical CT angiography

BACKGROUND AND PURPOSE

Many cases of subarachnoid hemorrhage are due to rupture of small cerebral aneurysms. Our purpose was to evaluate the usefulness of helical CT angiography (CTA) in the detection and characterization of very small (<5 mm) intracranial aneurysms.

METHODS

One hundred eighty consecutive patients underwent CTA for suspected intracranial aneurysms. All aneurysms prospectively detected by CTA were confirmed by digital subtraction angiography (DSA) or at surgery. CT angiograms and digital subtraction angiograms were reviewed by two independent blinded radiologists who performed aneurysm detection, quantitation, and characterization using 2D multiplanar reformatted and 3D volume-rendering techniques.

RESULTS

Fifty-one patients harboring 41 very small intracranial aneurysms were included in this series. Eighty-one percent (33 of 41 aneurysms) were </=4 mm in maximal diameter, and 37% (15 of 41 aneurysms) were </=3 mm in maximal diameter. Sensitivity of CTA for very small intracranial aneurysm detection ranged from 98% to 100% (95% confidence intervals, 0.871, 0.999, 0.914, and 1.0), compared with 95% for DSA. The specificity of CTA and DSA for very small intracranial aneurysms was 100% (26 of 26 aneurysms). Positive predictive value ranged from 98% to 100%. Negative predictive value ranged from 96% to 100%. Accuracy of CTA for detection of very small intracranial aneurysms was 99% and 100% (kappa = 0.969 - 1.0 +/- 0.1221). Forty-eight percent of aneurysms were detected in the presence of subarachnoid hemorrhage.

CONCLUSION

The sensitivity of CTA for the detection of cerebral aneurysms </=5 mm is higher than that of DSA, with equal specificity and high interoperator reliability. High quality, noninvasive CTA aneurysm detection and characterization can be performed using routine clinical CT scanners and commercially available image processing workstations.

Strategies in management of ruptured aneurysms--own experiences with various therapeutical procedures in severe SAH

A retrospective analysis of 58 patients with spontaneous SAH was conducted. 33 patients suffered on severe SAH, clinical grading IV and V (Hunt, Hess). 11 died without treatment due to decerebrate rigidity. 22 patients were treated, 16 underwent a clipping procedure and 6 were selected for endovascular coilembolization. A total of 14 SAH were associated with intracerebral, intraventricular or subdural hemorrhages. In fact of these in 10 patients first an evacuation of the haematoma or a ventricular drainage was necessary, two times combined with a decompressive craniectomy. In 4 patients the removal of haematoma was combined with clipping of aneurysm in one operation. After occlusion of aneurysm decompressive craniectomy was required in 3 patients, an evacuation of an intracerebral bleeding in 1 patient. 6 patients needed a permanent shunting system. The outcome according the Glasgow Outcome Score was: 4 died (GOS1), 12 were severely disabled (GOS3) and 6 were moderately disabled (GOS4).

[Complex approach to diagnosis and surgical treatment of patients with abdominal aortic aneurysm (classification)]

The problem of management of abdominal aortic aneurysm (AAA) is becoming urgent due to growing AAA incidence. Most often concomitant disease in them is coronary artery disease (CAD) which itself is a risk factor for life. The study was performed in 249 patients, who underwent. Surgery for AAA in RAMS Research Center for Surgery in 1975-1997. 142 (57%) of them had associated CAD. The use of complex approach to the diagnosis in this category of patients has made in possible last years to increase detection of CAD by more than 75%. In surgical management the principle of dominant in lesion of one of these regions was used. In critical conditions of both regions one stage regions was used. In critical conductions of both regions one stage reconstruction was performed. This technique is well developed now. The proposed classification helps to assess completely concomitant diseases in patients with AA and to determine policy of surgical treatment individual for each patients.

Ruptured giant intracranial aneurysms. Part II. A retrospective analysis of timing and outcome of surgical treatment

OBJECT

This retrospective study was made to determine the relationship between surgical timing and outcome in all patients with ruptured giant intracranial aneurysms undergoing surgical treatment at the Mayo Clinic between 1973 and 1996.

METHODS

The authors studied 109 patients, 102 of whom were referred from other medical centers. The ruptured giant aneurysms were 25 to 60 mm in diameter. One hundred five of the patients survived the rupturing of the aneurysm to undergo operation, with direct surgery possible in 84% of cases. Excluding delayed referrals, the average time to surgery after admission to the Mayo Clinic was approximately 4 to 5 days. Patients admitted earlier tended to be in poorer condition, often undergoing earlier operation. On average, surgical treatment was administered later for patients with ruptured aneurysms of the posterior circulation than for those with aneurysms in the anterior circulation. Temporary occlusion of the parent vessel was necessary in 67% of direct procedures, with an average occlusion time of 15.5 minutes. Among surgically treated patients, a favorable outcome was achieved in 72% harboring ruptured anterior circulation aneurysms and in 78% with ruptured posterior circulation lesions.

CONCLUSIONS

The overall management mortality rate was 21.1%, and the mortality rate for surgical management was 8.6%. The authors believe that because of the technical difficulties and risk of rebleeding associated with ruptured giant intracranial aneurysms, timely referral to and well-planned treatment at medical centers specializing in management of these lesions are essential to effect a more favorable outcome.

Aneurysmal subarachnoid hemorrhage: prognostic features and outcomes

The prognostic features and outcomes associated with aneurysmal subarachnoid hemorrhage (SAH) are reviewed. In the first section, the epidemiology of SAH is discussed with emphasis on prevalence, incidence, risk factors, heredity, activity, and seasonal variability. In the second section, the presentation, diagnosis, and treatment of patients with aneurysmal SAH is briefly reviewed. In the third section, the prognostic features associated with aneurysmal SAH are discussed with emphasis on neurologic condition and SAH grading scales, patient's age, aneurysm size and location, repeat hemorrhage, vasospasm, systemic disease, hypertensive response, computed tomograph features, hydrocephalus, timing of surgery, and expertise of the aneurysm center. Also in the third section, the prognostic features associated with unruptured aneurysms are discussed with emphasis on the actuarial risk of rupture, aneurysm size and location, and multiplicity of lesions. In the fourth and final section, the outcomes of aneurysmal SAH over the past 60 yrs are reviewed.

Hyperdynamic therapy: the nurse's role in the treatment of cerebral vasospasm

The onset of subtle diffuse ischemic neurological deficits often associated with cerebral vasospasm is a major cause of morbidity and mortality following aneurysmal subarachnoid hemorrhage. The exact etiology of cerebral vasospasm is unclear. Increasing intravascular volume, decreasing blood viscosity and inducing hypertension may help prevent or diminish neurological deficits from cerebral vasospasm by improving cerebral blood flow. An intensive multidisciplinary approach is necessary with the role of the neuroscience nurse being pivotal. An understanding of the subtle neurological changes suggestive of cerebral vasospasm and its effects leads to early recognition, and allows for rapid institution of therapy.

A new subarachnoid hemorrhage grading system based on the Glasgow Coma Scale: a comparison with the Hunt and Hess and World Federation of Neurological Surgeons Scales in a clinical series

OBJECTIVE

Although the Hunt and Hess Scale (HHS) and World Federation of Neurological Surgeons Scale (WFNSS) are the most widely used subarachnoid hemorrhage (SAH) grading systems, neither system has achieved universal acceptance. We propose a simplified grading system based entirely on the Glasgow Coma Scale (GCS), which compresses the 15-point GCS into five grades that are comparable with those of the HHS and WFNSS. We refer to this system as the GCS grading system and present a direct comparison with the HHS and WFNSS for predictive value regarding patient outcome and interrater reliability.

METHODS

We reviewed 291 consecutive patients with aneurysms treated at our institution between January 1992 and January 1996 and compared the admission grades from the GCS, WFNSS, and HHS with outcome measures at discharge from hospitalization. The Glasgow Outcome score was used as the major outcome measure to evaluate the predictive value of the three scales. Mortality and length of stay (LOS) were also evaluated as outcome measures. The predictive value of each scale was tested with an ordinal logistic regression model for Glasgow Outcome score, a logistic regression model for mortality data, and a linear regression model for LOS.

RESULTS

Using the logistic regression model, the GCS was the best predictor of discharge Glasgow Outcome score, with an odds ratio of 2.585 (P = 0.0001), compared with 2.311 (P = 0.0001) for the WFNSS and 2.262 (P = 0.0001) for the HHS. Using mortality data in the logistic model, the HHS was the best predictor, with an odds ratio of 3.391 (P = 0.0001), compared with 2.859 (P = 0.0001) for the GCS and 2.560 (P = 0.0001) for the WFNSS. Each of the three scales had a high predictive value for LOS, using a linear model. We discuss, however, the problematic nature of LOS as an outcome measure for SAH. Interrater reliability for each scale was evaluated using kappa statistics, based on 15 additional patients evaluated prospectively, and showed that the GCS grade also had the greatest interrater reliability, with a kappa of 0.46 (P = 0.0002), compared with 0.41 (P = 0.0005) for the HHS and 0.27 (P = 0.027) for the WFNSS.

CONCLUSION

We conclude that the GCS grade has equal or greater predictive value regarding outcome after SAH than do the currently used grading systems and that it has greater reproducibility across observers. Broader familiarity with the GCS among medical and paramedical personnel may further enhance the usefulness of the GCS grade over the HHS and WFNSS in providing a standardized, universally accepted grading system for SAH.

Guglielmi detachable coil embolization of acute intracranial aneurysm: perioperative anatomical and clinical outcome in 403 patients

From December 1990 to July 1995, the investigators participated in a prospective clinical study to evaluate the safety of the Guglielmi detachable coil (GDC) system for the treatment of aneurysms. This report summarizes the perioperative results from eight initial interventional neuroradiology centers in the United States. The report focuses on 403 patients who presented with acute subarachnoid hemorrhage from a ruptured intracranial aneurysm. These patients were treated within 15 days of the primary intracranial hemorrhage and were followed until they were discharged from the hospital or died. Seventy percent of the patients were female and 30% were male. The patients' mean age was 58 years old. Aneurysm size was categorized as small (60.8%), large (34.7%), and giant (4.5%); and neck size was categorized as small (53.6%), wide (36.2%), fusiform (6%), and undetermined (4.2%). Fifty-seven percent of the aneurysms were located in the posterior circulation and 43% in the anterior circulation. Eighty-two patients were classified as Hunt and Hess Grade I (20.3%), 105 Grade II (26.1%), 121 Grade III (30%), 69 Grade IV (17.1%), and 26 Grade V (6.5%). All patients in this study were excluded from surgical treatment either because of anticipated surgical difficulty (69.2%), attempted and failed surgery (12.7%), the patient's poor neurological (12.2%) or medical (4.7%) status, and/or refusal of surgery (1.2%). The GDC embolization was performed within 48 hours of primary hemorrhage in 147 patients (36.5%), within 3 to 6 days in 156 patients (38.7%), 7 to 10 days in 71 patients (17.6%), and 11 to 15 days in 29 patients (7.2%). Complete aneurysm occlusion was observed in 70.8% of small aneurysms with a small neck, 35% of large aneurysms, and 50% of giant aneurysms. A small neck remnant was observed in 21.4% of small aneurysms with a small neck, 57.1% of large aneurysms, and 50% of giant aneurysms. Technical complications included aneurysm perforation (2.7%), unintentional parent artery occlusion (3%), and untoward cerebral embolization (2.48%). There was a 8.9% immediate morbidity rate related to the GDC technique. Seven deaths were related to technical complications (1.74%) and 18 (4.47%) to the severity of the primary hemorrhage. The findings of this study demonstrate the safety of the GDC system for the treatment of ruptured intracranial aneurysms in anterior and posterior circulations. The authors believe additional randomized studies will further identify the role of this technique in the management of acutely ruptured incranial aneurysms.

Clinical grading and outcome after early surgery in aneurysmal subarachnoid hemorrhage

OBJECTIVE

We propose a modification to the currently prevailing grading systems in patients with subarachnoid hemorrhage. The changes will make them correlate more strongly with the surgical results.

METHODS

The relationship between preoperative clinical grades and management outcome was retrospectively investigated in a series of 304 patients with ruptured cerebral aneurysms on the anterior circle of Willis. Preoperatively, every patient was evaluated with the Hunt and Kosnik grading system, the World Federation of Neurological Surgeons Scale, and the Glasgow Coma Scale. All the patients underwent surgical treatment on the aneurysms within 72 hours of the first onset of symptoms. Hyperdynamic therapy was performed after the surgery was evaluated with the Glasgow Outcome Scale.

RESULTS

In the Hunt and Kosnik system, the outcome was significantly different between the patients with Grades II and III and those with Grades III and IV, but there was no significant difference among the adjacent grades except between patients with Glasgow Coma Scale scores of 13 and 14. The outcome of oriented patients was significantly better than that of confused patients. Neither eye opening nor presence of focal deficit was a significant prognostic factor.

CONCLUSION

To grade patients with subarachnoid hemorrhage objectively, three responses should be recorded separately in the Glasgow Coma Scale score. Patients with confused verbal responses should be graded lower than those who are oriented, even when they have the same total score.

Early management in poor grade aneurysm patients

Aneurysm surgery began in Lübeck only in 1986 when the department was completely reorganized. Early operation in the good grade patients (I-III, according to Hunt and Hess) was performed. In every case we also discussed the feasibility of operating on the poor grade patients (Hunt and Hess IV and V). During a five-year period (1986-1991) a total of 277 SAH patients were admitted to the department. 109 (39%) patients arrived in a poor grade (Hunt and Hess IV or V), 12 of these patients died within hours of admission. 25 patients, who presented with a large intracerebral and/or subdural haematoma, were urgently operated upon by haematoma evacuation and aneurysm clipping. An external ventricular drainage was performed on 72 patients. Of the ventriculostomy group 33 patients improved and 27 were operated upon. In 17 of the 39 patients without improvement after CSF-drainage we decided to operate. Overall 69 patients were surgically treated (craniotomy, aneurysm clipping) and 40 were not. The mortality rate in the surgical cases was 16 (23%) compared with 30 (75%) without operation. It is concluded that poor grade aneurysm patients can achieve a better outcome with active treatment based on immediate ventriculostomy and optimal haemodynamic parameters after haematoma evacuation and early occlusion of the aneurysm.

Management results attained by predominantly late surgery for intracranial aneurysms

In contrast to previous studies conducted by various authors, who recommended early surgery for all patients admitted to the hospital within 72 hours of an aneurysmal subarachnoid hemorrhage, several more recent studies have declined to advise early surgery for the treatment of patients with impaired consciousness. In our series, early surgery was undertaken for patients who were rated at Grades 1 to 2 (Hunt and Hess) at admission and who did not exhibit any additional risk factors (e.g., evidence of incipient vasospasm, giant aneurysm, unfavorable aneurysm location, or a severe concomitant disease). Only three patients rated Grade 3 at admission with a favorable aneurysm location and shape underwent early surgery. The management results attained in this series (n = 131), in which the early surgery rate was 17%, have been analyzed. The management mortality rate of patients with aneurysmal subarachnoid hemorrhage was 13%, and it was 7.7% for patients admitted at Grades 1 to 3 on the Hunt and Hess scale. Good results (Glasgow Outcome Scale, 1 or 2) were attained in 75% of the entire study population, in 85% of patients admitted at Grades 1 to 3, and in 53% of those patients who were admitted at Grades 4 to 5 and who underwent late surgery after their condition had improved to Grades 1 to 3. At an average interval of 3 years after the operation, 83% of the patients discharged with Glasgow Outcome Scale ratings of 1 or 2 reported no significant restriction of their "stress resistance."(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term monitoring of CSF lactate levels and lactate/pyruvate ratios following subarachnoid haemorrhage

Ventricular cerebrospinal fluid (CSF) lactate concentrations and lactate/pyruvate (L/P) ratios were measured daily in 20 patients from day 1 to day 12 after subarachnoid haemorrhage due to ruptured aneurysms. Patients without symptomatic vasospasm were classified in Group 1, patients with symptomatic vasospasm were classified in Group 2, and patients who were Hunt and Kosnik grade 4 on admission clinically were classified in Group 3. Patients in all three groups had high CSF lactate concentrations on day 1, and, especially in Group 3, the high lactate was accompanied by an increased L/P ratio and a decreased CSF bicarbonate. Lactate concentrations in Group 1 decreased throughout the observation period. Lactate concentrations in Group 2 also decreased but then began to increase again on days 5 to 7, correlating well with the onset of cerebral vasospasm. The delayed increase of CSF lactate in Group 2 was also accompanied by increases in the CSF pyruvate level and the CSF L/P ratio. Daily monitoring of CSF lactate may thus serve as a chemical marker for cerebral vasospasm.

Dorsal internal carotid artery aneurysm: classification, pathogenesis, and surgical considerations

Despite the rarity of dorsal internal carotid artery (ICA) aneurysms they still offer surgical challenge to achieve a safe successful clipping due to their peculiar projection. In the past 13 years, 24 cases of dorsal ICA aneurysm were operated upon in our hospitals. Three separate groups of such aneurysms could be identified: group 1; where the aneurysms were located most proximally at the carotid-ophthalmic region, group 3; in which the aneurysms were present most distally just proximal to the ICA bifurcation, and group 2; where the aneurysms were located in between. All cases in this surgical series will be reviewed stressing upon the classification, pathogenesis, and surgical tactics of such a rare type of aneurysm.