Evaluating the use and utility of noninvasive angiography in diagnosing traumatic blunt cerebrovascular injury.

BACKGROUND: Digital subtraction angiography (DSA) is the gold standard for radiographic diagnosis of blunt cerebrovascular injury (BCVI), but use of computed tomography angiography (CTA) and magnetic resonance angiography (MRA) has increased dramatically in BCVI screening. This study explores the utility, effectiveness, and cost of noninvasive CTA and MRA screening for BCVI. METHODS: Medical records of 2,025 consecutive adults evaluated for acute blunt neck trauma and BCVI were reviewed retrospectively. The incidence of BCVI, level(s) of cervical injury, involvement of foramina transversaria and internal carotid canals, presence of bony dislocation or subluxation, and subsequent treatment received were assessed. Asymptomatic patients were analyzed based on fracture and injury patterns. The cost effectiveness of CTA compared with DSA and the effects of CTA sensitivity and screening yield were determined. RESULTS: Of reviewed patients, 196 received CTA or MRA. Thirty-eight patients (19.4%) were diagnosed with BCVI. Screening yield in patients symptomatic at presentation was 48.8%. Large-vessel internal carotid, vertebral, anterior spinal, and basilar artery occlusion were associated with a positive screen, as were concurrent stroke and spinal cord injury (p < 0.01). Of patients with injuries found with noninvasive imaging, 50.0% of BCVI involved C1-3 fracture, 34.2% involved subluxation, and 65.8% involved foramina transversaria. In both symptomatic and asymptomatic patients, CTA screening was more cost effective than DSA. CONCLUSION: Noninvasive imaging is a safe, accurate, and cost-effective tool for BCVI screening. Symptomatic presentation was the best predictor of BCVI. Significant cost savings were realized using CTA rather than DSA, with similar effectiveness and patient outcomes. LEVEL OF EVIDENCE: Diagnostic study, level III; economic analysis, level IV.

Neurointerventional procedural volume per hospital in United States: implications for comprehensive stroke center designation.

BACKGROUND AND PURPOSE: Availability of neurointerventional procedures is recommended as a necessary component of a comprehensive stroke center by various regulatory guidelines that also emphasize adequate procedural volumes. We studied the volumes of neurointerventional procedures performed in various hospitals across the United States with subsequent comparisons with rates of minimum procedural volumes recommended by various professional bodies or used in clinical trials to ensure adequate operator experience. METHODS: We reviewed the Nationwide Inpatient Sample database in the United States for the years 2005 to 2008. Using International Classification of Disease-Clinical Modification, 9th revision, and Medicare severity diagnosis-related group codes, we identified among hospitals that admit stroke patients those that met the minimum criteria for overall and individual procedural volumes specified in various guidelines. We then compared the characteristics between the high-volume hospitals that performed at least 100 cervicocerebral angiograms and met ≥1 other procedural criterion (n=79) and low-volume hospitals (n=958). RESULTS: Proportions of hospitals that met individual procedural volume criteria over the 4-year period according to procedure were: cervicocerebral angiography (7.0%-7.8%); endovascular acute ischemic stroke treatments (0.4%-2.6%); carotid angioplasty/stent placement (3.0%-5.3%); intracranial angioplasty/stent placement (0.3%-1.3%); and aneurysm embolization (1.3%-2.6%). There were significant trends for increasing numbers of all the endovascular procedures except intracranial angioplasty/stent placement over the course of 4 years. The high-volume hospitals were more likely to be urban teaching hospitals (70.9% versus 13.1%; P<0.001), had larger bed size (79.7% versus 26.9%; P<0.001), and had significantly higher rates of hemorrhagic stroke admissions and lower rates of transient ischemic attack admissions. Urban teaching location/status (OR, 8.92; CI, 4.3-18.2; P<0.001) and large bed size (OR, 4.40; CI, 2.0-9.5; P<0.001) remained as independent predictors of a high-volume hospital when adjusted for age, gender, risk factors, and stroke subtype. CONCLUSIONS: There are very few hospitals in the United States that meet all the neurointerventional procedural volume criteria for all endovascular procedures recommended to ensure adequate operator experience. Our results support the creation of specialized regional centers for ensuring adequate procedural volume within treating hospitals.

Endovascular neurosurgery in the United States: a survey of 59 vascular neurosurgeons with endovascular training.

OBJECTIVE: We sought to assess general aspects of endovascular neurosurgery training, practice, and management for the treatment of intracranial aneurysms, arteriovenous malformations, acute ischemic stroke, and extracranial or intracranial occlusive disease within neurosurgery training and practice in the United States. METHODS: A questionnaire was sent electronically to 80 U.S. neurosurgeons with endovascular training. RESULTS: Fifty-nine surveys (74%) were returned. Survey responses illustrated different practice patterns and varying management of cerebrovascular disorders by neurosurgeons with endovascular training. CONCLUSION: Our findings provide a snapshot of current neurosurgical endovascular practices in the United States.

Observer agreement in the assessment of endovascular aneurysm therapy and aneurysm recurrence.

BACKGROUND AND PURPOSE: Assessments of completeness of endovascular cerebral aneurysm therapy are commonly reported in the literature. We studied several aneurysm assessment scales with regard to observer variability, which directly affects validity of these scales. MATERIALS AND METHODS: Initial aneurysm occlusion and occlusion at a follow-up angiogram at 3-6 months were assessed independently by 2 experienced observers. Assessments of each aneurysm were made using 3 different scales: 4-response (complete, dog ear, neck remnant, incomplete), 3-response (complete, near-complete, incomplete), and 2-response (complete or near-complete, incomplete). Assessments were also made of comparisons of initial treatment angiogram with follow-up angiogram using 2 different scales: 3-response (better, same, worse) and 2-point response (not worse, worse). RESULTS: With assessments of both initial and follow-up angiograms, interobserver and intraobserver agreement was progressively worse with increasing response choices in the scales. Observer agreement on assessments of initial angiograms (kappa values 0.48-0.67) was worse than that for follow-up angiograms (kappa values 0.66-0.97). For the comparisons of the initial angiogram with the follow-up angiogram, there was worse observer agreement with the 3-response scale (kappa values 0.64-0.71) than with the 2-response scale (kappa values 0.78-0.89). CONCLUSION: Interobserver and intraobserver variability are inherent to assessment scales of completeness of cerebral aneurysm therapy. Observer variability is substantially better in scales that offer fewer observer responses. However, scales with fewer observer responses may not identify aneurysm subgroups that have differing risks of recurrence and/or rehemorrhage.

Inter- and intraobserver variability in the assessment of brain arteriovenous malformation angioarchitecture and endovascular treatment results.

BACKGROUND AND PURPOSE: Several angiographic features of brain arteriovenous malformations (BAVMs) have been associated with an increased risk of hemorrhage. However, interpretation of these features may not be consistent between observers. We conducted a study to determine inter- and intraobserver agreement of various angioarchitectural characteristics of BAVM. MATERIALS AND METHODS: Two experienced interventional neuroradiologists independently reviewed pre- and post-endovascular treatment angiograms from 50 consecutive patients. Axial CT and/or MR images before treatment were included. We collected the following data: Spetzler-Martin grades, number of involved arterial territories, associated aneurysms by location (circle of Willis, feeding artery, intranidal, and venous), and nidus reduction after endovascular treatment (<33%, 33%-66%, and >66%). The reviewers were compared with each other, and 1 was compared with himself after a 3-month interval. Measures of agreement were performed by using the kappa statistic (kappa) for nominal data and the weighted kappa for ordinal data. RESULTS: Inter- and intraobserver agreement were higher for assessment of the Spetzler-Martin grade (weighted kappa = 0.70/0.75) and nidus size reduction after endovascular treatment (kappa = 0.74/0.77). Inter- and intraobserver agreement were inferior for findings concerning feeding artery aneurysms (kappa = 0.19/0.36), intranidal aneurysms (kappa = 0.34/0.35), and venous aneurysms (kappa = 0.50/0.67). CONCLUSION: Angiographic characteristics of BAVMs considered as risk factors for hemorrhage, such as aneurysms, are not reliably detected on global angiograms between different observers. In contrast, the Spetzler-Martin grading system and angiographic results of endovascular treatment can be used with high observer agreement.

Aneurysmal surgery in the presence of angiographic vasospasm: an outcome assessment.

BACKGROUND AND PURPOSE: The timing of aneurysmal surgery for patients presenting within the period at risk for vasospasm (VS) is controversial. The goal of this study is to review our experience of surgically treated patients in the presence of angiographic VS. MATERIALS AND METHODS: From 1990-2004, 894 consecutive patients presented with an aneurysmal subarachnoid hemorrhage (SAH) and were treated with a policy of early surgery. We retrospectively analyzed the patients that had pre-operative angiographic VS. In this study, symptomatic VS was diagnosed when a decreased level of consciousness and/or focal deficit occurred after SAH in the presence of angiographic VS without confounding factors. Functional outcome was assessed three months after SAH using the Glasgow Outcome Scale. RESULTS: Of the 40 patients studied, 62.5% were in good clinical grade Hunt & Hess (H&H 1-2) on admission; 25%, intermediate grade (H&H 3); 12.5%, poor grade (H&H 4-5). Surgery was performed 24 hours or less after initial angiography in 87.5% of patients and less than 48 hours in 97.5%. Pre-operative symptomatic VS was diagnosed in 25%. Post-operatively, angiographic VS was documented in 87.2%. Of the 30% of patients that presented post-operative symptomatic VS, 66.7% also demonstrated pre-operative symptomatic VS. The functional outcome was favorable in 92.5% of the studied patients. Two deaths occurred in patients presenting pre-operative early radiological and symptomatic VS. CONCLUSION: Aneurysmal surgery, especially between 3-12 days following SAH, in the presence of asymptomatic pre-operative angiographic VS can be associated with a good outcome. Early surgery is not contra-indicated and might enable optimal treatment of VS.

Assessment: transcranial Doppler ultrasonography: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.

OBJECTIVE: To review the use of transcranial Doppler ultrasonography (TCD) and transcranial color-coded sonography (TCCS) for diagnosis. METHODS: The authors searched the literature for evidence of 1) if TCD provides useful information in specific clinical settings; 2) if using this information improves clinical decision making, as reflected by improved patient outcomes; and 3) if TCD is preferable to other diagnostic tests in these clinical situations. RESULTS: TCD is of established value in the screening of children aged 2 to 16 years with sickle cell disease for stroke risk (Type A, Class I) and the detection and monitoring of angiographic vasospasm after spontaneous subarachnoid hemorrhage (Type A, Class I to II). TCD and TCCS provide important information and may have value for detection of intracranial steno-occlusive disease (Type B, Class II to III), vasomotor reactivity testing (Type B, Class II to III), detection of cerebral circulatory arrest/brain death (Type A, Class II), monitoring carotid endarterectomy (Type B, Class II to III), monitoring cerebral thrombolysis (Type B, Class II to III), and monitoring coronary artery bypass graft operations (Type B to C, Class II to III). Contrast-enhanced TCD/TCCS can also provide useful information in right-to-left cardiac/extracardiac shunts (Type A, Class II), intracranial occlusive disease (Type B, Class II to IV), and hemorrhagic cerebrovascular disease (Type B, Class II to IV), although other techniques may be preferable in these settings.

Assessment of regional acute stroke unit care in Italy: the PROSIT study.

BACKGROUND/OBJECTIVES: The aim of this study was to survey acute in-hospital stroke services in seven Italian regions. METHODS: Regional hospital discharge registers were searched to identify hospital services that record at least 50 acute stroke discharges per year and the doctors in charge of these services were interviewed. RESULTS: Only 31 (7%) out of 447 services could be classified as stroke units (SUs). Of these, only 9 (29%) were found to have vital function monitoring systems available for all patients. The most striking differences between SUs and mixed stroke services emerged when comparing staff/patient ratios in the two types of unit. CONCLUSIONS: There are still not enough SUs in Italy, and fewer than 10% of stroke patients can be admitted to such units.

Observer agreement in the angiographic assessment of arteriovenous malformations of the brain.

PURPOSE: We aimed to determine intraobserver and interobserver agreement in the characterization of brain arteriovenous malformation (AVM) angioarchitecture on intra-arterial digital subtraction angiograms. METHODS: Five experienced interventional neuroradiologists independently reviewed 40 anonymized angiograms obtained at the time of first-ever AVM diagnosis. The allocation of the films to observers was balanced for AVM size and complexity. Every observer was compared with himself and all the others by distributing the films in 2 batches 3 months apart. The observers used standard forms to collect both quantitative and categorized qualitative angiographic data. To measure agreement we used the kappa statistic (kappa) for nominal data, weighted kappa for ordinal and discrete interval data, and Bland & Altman analysis for continuous data. RESULTS: Intraobserver agreement was generally moderate to substantial, with 95% confidence intervals ranging from fair to almost perfect. However, for every characteristic, interobserver agreement was less than intraobserver agreement. Interobserver agreement was generally slight to moderate, with 95% confidence intervals ranging from less than chance to almost perfect. CONCLUSION: This study demonstrates the need for robust and generalizeable definitions of AVM angioarchitecture and methods of nidus size measurement-with proof of good intraobserver and interobserver agreement-for future efforts to understand the prognosis and best treatment of AVMs.

Perimesencephalic hemorrhage and CT angiography: A decision analysis.

BACKGROUND AND PURPOSE: The method of choice for detecting or excluding a vertebrobasilar aneurysm still is a matter of debate in patients with a characteristically perimesencephalic pattern of subarachnoid hemorrhage (SAH) on CT. We used decision analysis to compare possible diagnostic strategies in these patients. METHODS: A decision analytic model was developed to evaluate the effect of 4 different diagnostic strategies following a perimesencephalic pattern of SAH on CT: 1, no further investigation; 2, digital subtraction angiography (DSA) by catheter; 3, CT angiography as initial modality, not followed by DSA if negative; and 4, CT angiography as initial modality, followed by DSA. We used a 4% prevalence of a vertebrobasilar aneurysm given a perimesencephalic pattern of hemorrhage, a 97% sensitivity and specificity of CT angiography, and a 99.5% sensitivity and 100% specificity of DSA. In a prospectively collected series, the complication rate from DSA in patients with a perimesencephalic pattern of hemorrhage was 2.6%. We calculated the expected utility of each of the 4 diagnostic options and used sensitivity analyses to examine the influence of the plausible ranges of the various estimates used. RESULTS: The expected utilities were 99.09 for CT angiography only, 98.96 for no further investigation, 98.22 for DSA, and 96.34 for CT angiography plus DSA. The results of the sensitivity analysis indicate that over a wide range of assumptions, CT angiography only is the most beneficial option. Only when the complication rate of catheter angiography is <0.2% is DSA the preferred strategy. CONCLUSIONS: Our decision analysis shows that in patients with a perimesencephalic pattern of hemorrhage on CT, CT angiography only is the best diagnostic strategy. DSA can be omitted in patients with a perimesencephalic pattern of hemorrhage and a negative CT angiogram.

Changing trends in the use of preoperative carotid arteriography: the community experience.

Between 1 January 1991 and 31 December 1994, 215 carotid endarterectomies were performed at the authors' institution, which utilized a clinical pathway. Prior to May 1992, arteriography was performed routinely. A near perfect correlation was found between the arteriograms and duplex scans when they were compared as part of the Intersocietal Commission for the Accreditation of Vascular Laboratories (ICAVL) vascular laboratory accreditation process. A policy of selective arteriography was instituted in May 1992. Only 11 arteriograms were performed on the next 148 patients (7%) who underwent carotid endarterectomies. Arteriography was performed on two patients with extremely high bifurcations, and five patients when an exact degree of stenosis could not be determined. Two patients with simultaneous mid common carotid and bifurcation stenoses had arteriography to confirm the duplex findings. Arteriography confirmed a long, high-grade internal carotid artery stenosis, which was felt to be operable by duplex, and a simultaneous bifurcation and suspected left common carotid orificial stenosis in one patient each. Arteriograms were performed on three non-operated patients felt to have occluded internal carotid artery on duplex scanning. Two had string-like internal carotid arteries that extended intracranially from the bifurcation, and one patient had an internal carotid artery dissection. Duplex results were grossly confirmed at operation and pathologically. There were no neurological complications in those patients undergoing carotid endarterectomies based on the results of duplex scanning alone. Carotid endarterectomies can be safely performed based on the results of a duplex scan performed in an accredited vascular laboratory. This approach eliminates the risk and cost of arteriography. Approximately 10% of patients will require arteriography if the duplex scan is equivocal or shows disease at other areas than the carotid bifurcation.

Safe and cost-effective approach to carotid surgery.

OBJECTIVE: To evaluate the safety and cost effectiveness of carotid surgery performed altering the perioperative protocol in an attempt to decrease resource utilisation. SETTING: Department of vascular surgery in a large metropolitan teaching hospital in northern Italy. DESIGN: Prospective, non-selective study. MATERIALS AND METHODS: Three hundred and eighty carotid procedures were performed in 1995 on 343 patients (274 males, 69 females, mean age 68.2 years, range 47-86 years). The most important cost containment measures, were: (i) limiting the use of contrast arteriography to cases of dubious ultrasonographic diagnosis; (ii) routine use of loco-regional anaesthesia; (iii) postoperative admission to an intensive care unit (ICU) only in selected cases; (iv) early postoperative discharge where possible. RESULTS: Mortality was 0.26% and neurological morbidity 1.58%. General anaesthesia was required in eight patients (2.1%), and only seven patients (1.8%) were admitted postoperatively to the ICU. Arteriography was performed in 56 cases (14.7%). The average hospital stay was 5 days with a global cost of 43,036 ECU, as compared with a cost of 6764 ECU for patients treated traditionally with routine arteriography, general anaesthesia and routine ICU admission. CONCLUSIONS: Selective use of arteriography and ICU, routine use of loco-regional anaesthesia and reduced hospital stay make it possible to lower the cost of carotid surgery without sacrificing quality.

Radiological assessment of stenosis of the internal carotid artery at the junction with the common.

Stenoses at the origin of 100 internal carotid arteries from patients with ischemic cerebrovascular disease were studied by intra-arterial angiography. Three principles were employed to evaluate the degree of stenosis: 1) verbal description, grading stenoses as mild, moderate of severe, 2) estimation of the true residual diameter, and 3) calculation of percent stenosis, defined here as the diameter of the artery at the origin relative to that at the level of the angle of the mandible. The true diameter, estimated to the nearest whole mm, corresponded well with the verbal description, and correlated significantly with percent stenosis. Since the true diameter is precisely defined, easy to estimate, and directly related to its hemodynamic effect, we suggest that this simple parameter, rather than the more commonly used, but more vaguely defined term "percent lumen reduction", is used to grade stenoses of the internal carotid artery.

The effect of the computed tomographic scanner on utilization and charges for alternative diagnostic procedures.

Monthly utilization data for four diagnostic procedures (electroencephalography, brain scintigraphy, pneumoencephalography, and cerebral angiography) over a 10-year period were collected from a neurological institute. The computed tomographic (CT) scanner was introduced in the seventh year. Its effect on the usage of the alternative procedures was examined using three measures: (a) computing pre- and post-CT average monthly usage, (b) comparing fitted curves for the pre- and post-CT periods, and (c) projecting usage had the scanner not been available. Projected charges were compared with actual charges, and the scanner was found to be charge-saving in the second and third years of its use.

Neurodiagnostic tests in children with brain tumors: changing patterns of use and impact on cost.

The utilization of neurodiagnostic tests in the initial work-up in children with brain tumors was relatively stable during the three years before computed tomography (CT) became available. After this test became available there was a significant (P less than .05) reduction in the utilization of cerebral angiography, echoencephalography, electroencephalography, and ventriculography in children with tumors below the tentorium. In children with tumors above the tentorium, only a reduction in the use of cerebral angiography and radioisotopic scanning was demonstrated. These changes have resulted in a significant (P less than .05) reduction in cost to the patient (or third party) for the initial neurodiagnostic work-up. Since CT became available, children with brain tumors undergo fewer tests, and the greatest reduction has been in tests that have the greatest cost.