Methodology of the Interventional Management of Stroke III Trial

RATIONALE

The Interventional Management of Stroke (IMS) I and II pilot trials demonstrated that the combined intravenous (i.v.) and intraarterial (i.a.) approach to recanalization may be more effective than standard i.v. rt-PA (Activase) alone for moderate-to-large National Institutes of Health Stroke Scale (NIHSS>or=10) strokes, and with a similar safety profile.

AIMS

The primary objective of this NIH-funded, Phase III, randomized, multicenter, open-label clinical trial is to determine whether a combined i.v./i.a. approach to recanalization is superior to standard i.v. rt-PA alone when initiated within 3 h of acute ischemic stroke onset. The IMS III trial will develop and maintain a network of interventional centers to test the safety, feasibility, and potential efficacy of new FDA-approved catheter devices as part of a combined i.v./i.a. approach to recanalization as the IMS III study progresses. A secondary objective of the IMS III trial is to determine the cost-effectiveness of the combined i.v./i.a. approach as compared with standard i.v. rt-PA. Trial enrollment began in July of 2006.

DESIGN

A projected 900 subjects with moderate-to-large (NIHSS>or=10) ischemic strokes between ages 18 and 80 will be enrolled over the next 5 years at 40-plus centers in the United States and Canada. Patients must have i.v. treatment initiated within 3 h of stroke onset in both arms. Subjects will be randomized in a 2 : 1 ratio with more subjects enrolled in the combined i.v./i.a. group. The i.v. rt-PA alone group will receive the standard full dose [0.9 mg/kg, 90 mg maximum (10% as bolus)] of rt-PA intravenously over an hour. The combined i.v./i.a. group will receive a lower dose of i.v. rt-PA ( approximately 0.6 mg/kg, 60 mg maximum) over 40 min, followed by immediate angiography. If a treatable thrombus is not demonstrated, no i.a. therapy will be administered. If an appropriate thrombus is identified, treatment will continue with either the Concentric Merci thrombus-removal device, infusion of rt-PA and delivery of low-intensity ultrasound at the site of the occlusion via the EKOS Micro-Infusion Catheter, or infusion of rt-PA via a standard microcatheter. If i.a. rt-Pa therapy is the chosen strategy, a maximum of 22 mg of i.a. rt-PA may be given. The choice of i.a. strategy will be made by the treating neurointerventionalist. The i.a. treatment must begin within 5 h and be completed within 7 h of stroke onset.

STUDY OUTCOMES

The primary outcome measure is a favorable clinical outcome, defined as a modified Rankin Scale Score of 0-2 at 3 months. The primary safety measure is mortality at 3 months and symptomatic ICH within the 24 h of randomization.

Microcatheter contrast injections during intra-arterial thrombolysis may increase intracranial hemorrhage risk

BACKGROUND AND PURPOSE

During intra-arterial revascularization, either guide catheter injections of contrast in the neck or microcatheter contrast injections (MCIs) at or beyond the site of an occlusion, can be used to visualize intracranial vasculature. Neurointerventionalists vary widely in their use of MCIs for a given circumstance. We tested the hypothesis that MCIs are a risk factor for intracranial hemorrhage (ICH) in the Interventional Management of Stroke (IMS) I and II trials of combined intravenous/IA recombinant tissue plasminogen activator therapy.

METHODS

All arteriograms with M1, M2, and ICA terminus occlusions were reanalyzed (n=98). The number of MCIs within or distal to the target occlusion was assigned. Postprocedure CTs were reviewed for contrast extravasation and ICH. Contrast extravasation was defined as a hyperdensity suggestive of contrast (Hounsfield unit >90) seen at 24 hours or present before 24 hours and persisting or replaced by ICH at 24 hours.

RESULTS

In this IMS subset, the rate of any ICH was 58% (57 of 98). More MCIs were seen in the ICH group (median=2 versus 1; P=0.04). Increased MCIs were associated with higher ICH rates (P=0.03). MCIs remained associated with ICH in multivariable analysis (P=0.01) as did baseline CT edema/mass effect, atrial fibrillation, time to intravenous recombinant tissue plasminogen activator initiation, and Thrombolysis in Cerebral Infarction reperfusion score. MCIs were also associated with contrast extravasation in unadjusted and adjusted analyses.

CONCLUSIONS

MCIs may risk ICH in the setting of combined intravenous/intra-arterial recombinant tissue plasminogen activator therapy, possibly due to contrast toxicity or pressure transmission by injections. MCIs should be minimized whenever possible. These findings will be tested prospectively in the IMS III trial.

Direct ascending pharyngeal artery to jugular vein arteriovenous fistula. A case report

SUMMARY

A 32-year-old female developed a bruit, determined to arise from a rare direct arteriovenous (AV) fistula from the ascending pharyngeal artery to the internal jugular vein.The fistula was treated by transarterial silicone balloon occlusion, with occlusion of fistulous flow, ablation of symptoms, and excellentlong-term result.

Large arachnoid granulations involving the dorsal superior sagittal sinus: findings on MR imaging and MR venography

BACKGROUND AND PURPOSE

Large arachnoid granulations (AG) within the dorsal superior sagittal sinus (SSS) have been incompletely characterized and can be confused with pathology. This report reviews the characteristics of these anatomic structures to establish common imaging features that allow differentiation from pathology.

MATERIALS AND METHODS

Twelve cases of large AG in the dorsal SSS are presented, identified by MR imaging. Signal intensity characteristics, size, location, venographic appearance, and association with adjacent venous and osseous structures were documented.

RESULTS

A defect in the dura of the SSS was seen in all of the cases communicating with the subjacent subarachnoid space. The average size of the AG was 8.1 x 9.4 x 10.0 mm (range, 4-19 mm). Ten produced calvarial remodeling, and 11 were in the direct vicinity of the lambda. On T2-weighted images, all were hyperintense to the brain. On T1-weighted images, 8 were hypointense and 4 were hypointense with mixed areas of isointense signal intensity. All of the AGs were associated with cortical venous structures entering the sinus. On MR venography, AGs appeared as focal protrusions into the sinus, displacing, distorting, and narrowing the sinus lumen. Seven patients had headache without other visible cause on MR imaging, and 4 were initially interpreted as thrombosis or tumor.

CONCLUSION

Large AGs can occur in the dorsal SSS. They are well-defined projections of the subarachnoid space into the sinus, can cause luminal narrowing and calvarial remodeling, and have typical signal intensity characteristics, position, and morphology differentiating them from other pathology. Association with patient symptoms is uncertain.

Brain parenchymal signal abnormalities associated with developmental venous anomalies: detailed MR imaging assessment

BACKGROUND AND PURPOSE

The occurrence of brain parenchymal signal-intensity changes within the drainage territory of developmental venous anomalies (DVAs) in the absence of cavernous malformations (CMs) has been incompletely assessed. This study was performed to evaluate the prevalence of brain parenchymal signal-intensity abnormalities subjacent to DVA, correlating with DVA morphology and location.

MATERIALS AND METHODS

One hundred sixty-four patients with brain MR imaging with contrast studies performed from July 2005 through June 2006 formed the study group. The examinations were reviewed and data were collected regarding the following: location, depth, size of draining vein, associated increased signal intensity on fluid-attenuated inversion recovery and T2-weighted images, associated CMs, and associated signal intensity on gradient recalled-echo sequences.

RESULTS

Of the 175 DVAs identified, 28 had associated signal-intensity abnormalities in the drainage territory. Seven of 28 DVAs with signal-intensity abnormalities were excluded because of significant adjacent white matter signal-intensity changes related to other pathology overlapping the drainage territory. Of the remaining DVAs imaged in this study, 21/168 (12.5%) had subjacent signal-intensity abnormalities. An adjusted prevalence rate of 9/115 (7.8%) was obtained by excluding patients with white matter disease more than minimal in degree. Periventricular location and older age were associated with DVA signal-intensity abnormality.

CONCLUSION

Signal-intensity abnormalities detectable by standard clinical MR images were identified in association with 12.5% of consecutively identified DVAs. Excluding patients with significant underlying white matter disease, we adjusted the prevalence to 7.8%. The etiology of the signal-intensity changes is unclear but may be related to edema, gliosis, or leukoaraiosis secondary to altered hemodynamics in the drainage area.

Eye position information on CT increases the identification of acute ischemic hypoattenuation

BACKGROUND AND PURPOSE

It is possible that identification of eye deviation may sensitize a scan reader to early brain hypodensity associated with an arterial occlusive process. Our aim was to investigate the value of observing eye deviation on blinded CT identification of early hypoattenuation following ischemic infarct.

MATERIALS AND METHODS

Two staff and 2 fellow neuroradiologists reviewed 75 brain CT scans obtained within 3 hours of acute ischemia from subjects in the Interventional Management of Stroke Study. Films were reviewed 3 months apart, the first time with tape over the eyes on the images, the second with the eyes visible. Readers were asked if early hypoattenuation in the middle cerebral artery (MCA) distribution or if a hyperattenuated MCA was present. kappa statistics were calculated to determine agreement among the 4 readers and between each of the 2 readings by the same reader, not only for the original interpretation of the blinded study neuroradiologist but also for the Alberta Stroke Program Early CT Score (ASPECTS) for each subject assigned by an unblinded expert panel. A generalized estimating equations modeling approach was used to look at the overall effect of including eye information for agreement between interpretations.

RESULTS

Eye information availability was associated with improved agreement for detection of early ischemic hypoattenuation not only among the 4 readers but also between the 4 readers and both the blinded study neuroradiologist (P = .02) and the unblinded expert ASPECTS panel. When comparing first and second readings for hypoattenuation, we also noted increased mean values for sensitivity (46.8% first, 56.5% second), specificity (78.2%, 80.2%), positive predictive value (72.0%, 80.7%), negative predictive value (55.5%, 61.0%), and percentage agreement (61.0%, 67.5%).

CONCLUSION

Observation of CT eye deviation significantly improves reader identification of acute ischemic hypoattenuation.

A multidisciplinary approach to carotid paragangliomas

The surgical management of carotid paragangliomas can be problematic. A multidisciplinary approach was used to include vascular surgery, otolaryngology, and neuroradiology to treat these patients over 9 years. From January 1992 to July 2001, a multidisciplinary team evaluated patients with carotid paragangliomas. Analyzed patient data included age, gender, diagnostic evaluation, tumor size, preoperative tumor embolization, operative exposure, need for extracranial arterial sacrifice/reconstruction, postoperative morbidity including cranial nerve dysfunction, and long-term follow-up. Twenty-five carotid paragangliomas in 20 patients underwent multidisciplinary evaluation and management. Average age was 51 years (range, 28-83 years), and 52% were male. Diagnostic evaluation included computed tomography in 76%, magnetic resonance imaging/magnetic resonance angiography in 52%, catheter angiography in 60%, and duplex ultrasonography in 16%. An extended neck exposure was required in 11 cases (44%), mandibulotomy was used once (4%), and mandibular subluxation was never required. The external carotid artery (ECA) was sacrificed in 8 cases (32%). The carotid bifurcation was resected in 1 patient (4%) requiring interposition reconstruction of the internal carotid artery. Preoperative tumor embolization was performed for 13 tumors (52%). Operative blood loss for patients undergoing preoperative embolization (Group I) was comparable to the nonembolized group (group II): group I lost 365 +/-180 mL versus 360 +/- 101 mL for group II (P = .48). This occurred despite larger tumors (group I - 4.2 cm versus group II - 2.1 cm, P = .03) and a higher mean Shamblin class (group I - 2.5 versus group II - 1.45, P = .001) for group I. There were no perioperative mortalities. Transient cranial nerve dysfunction occurred in 13 CBTs (52%), 2 (8%) of which remained present after 4 months. Patients with carotid paragangliomas benefit from a multidisciplinary team approach. Neuroradiology has been used for selective preoperative embolization, which has decreased estimated blood loss during excision of larger complex tumors. A combined surgical team of otolaryngology and vascular surgery provides for exposure of the distal internal carotid artery as high as the skull base, limited permanent cranial nerve dysfunction, and selective early division and excision of the external carotid artery for complete tumor resection.

Using the baseline CT scan to select acute stroke patients for IV-IA therapy

BACKGROUND

Intra-arterial therapies for acute ischemic stroke are increasingly available. Intravenous therapy (IV) followed immediately by intra-arterial therapy (IA) has been shown to be safe, but such therapy is resource intensive. Selecting the best patients for this therapy may be accomplished with the use of baseline neuroimaging.

METHODS

We used data from the IMS-1 and National Institute for Neurological Disorders and Stroke tissue plasminogen activator (tPA) stroke studies to compare outcomes among IV-IA tPA, IV-tPA, and placebo treatment stratified by the baseline CT scan appearance. The CT scans were scored using the Alberta Stroke Program Early CT (ASPECT) score and dichotomized into ASPECT score > 7 (favorable scan) and ASPECT score < or = 7 (unfavorable scan). Logistic regression was used to assess for an ASPECT score by treatment interaction.

RESULTS

A total of 460 patients was included. Age and sex were similar among the 3 groups. The IV-IA tPA cohort had a higher median National Institutes of Health stroke scale (NIHSS) score (18 versus 17) compared with the IV tPA cohort. The proportion of patients with favorable CT scans (ASPECT score > 7) was lowest in the IV-IA tPA group. A multiplicative interaction effect was shown indicating that patients with an ASPECT score > 7 in the IV-IA cohort were more likely to have a good outcome compared with IV tPA and with placebo. Harm may accrue to patients treated with IV-IA therapy who have an unfavorable baseline CT scan appearance.

CONCLUSIONS

Patients with a favorable baseline CT scan appearance are the most likely to benefit from IV-IA therapy. This hypothesis will be tested in the IMS-3 study.

Subdural hemorrhage in the posterior fossa caused by a ruptured cavernous carotid artery aneurysm after a balloon occlusion test

✓Given the relatively benign natural history of cavernous carotid artery aneurysms and based on anecdotal reports in the literature of subarachnoid hemorrhage (SAH) or subdural hemorrhage (SDH) from these aneurysms, observation is warranted and typically recommended. In this case report, the authors describe a woman who harbored a partially thrombosed, giant cavernous aneurysm that ruptured after she underwent a balloon occlusion test (BOT) and predominately led to an SDH. The authors believe that this occurrence is the first such report in the English literature. They discuss possible mechanisms for this event and the literature related to SAH or SDH from cavernous aneurysms, including why cavernous aneurysms cause such hemorrhages. The authors also recommend that attention be paid to such lesions regarding the possibility of aneurysmal rupture following a BOT.

Radiographic imaging of the distal dural ring for determining the intradural or extradural location of aneurysms

The effectiveness of several anatomical and radiological landmarks proposed to determine whether an aneurysm is located intradurally or extradurally is still debated. In anatomical and radiological studies, we examined the relationships of the distal dural ring (DDR) to the internal carotid artery (ICA) and surrounding bony structures to aid in the localization of aneurysms near the DDR. Anatomical relationships were examined by performing dissections on 10 specimens (5 formalin-fixed cadaveric heads). After the position of the DDR, optic nerve, and tuberculum sellae were marked with surgical steel wire, radiographs were taken in multiple projections. The only bony landmark consistently visible on radiographs was the planum sphenoidale. The superior border of the DDR is located at or below the level of the tuberculum sellae, which laterally becomes the superomedial aspect of the optic strut; thus, the optic strut marks the dorsal limit of the DDR. On 50 dry skulls, we measured the vertical distance between the planum sphenoidale and medial aspect of the optic strut (5.0 +/- 0.4 mm), the interoptic strut distance (14.4 +/- 1.4 mm), and the linear distance between the most posterior aspect of the planum sphenoidale (limbus sphenoidale) and the tuberculum sellae (6.0 +/- 0.5 mm). Using these measurements and the planum sphenoidale, tuberculum sellae, and optic strut as reference landmarks, we determined the location of the aneurysm relative to the DDR on angiographic images. In this way, we were able to identify whether lesions were intra- or extradural.

Left vertebral artery origin from the thyrocervical trunk: a unique vascular variant

The vertebral artery normally arises from the subclavian artery, and variations in its origin have been described. We describe a unique case of the left vertebral artery arising from the thyrocervical trunk.

Persistent falcine sinus in an adult: demonstration by MR venography

The falcine sinus is a normal anatomic structure located in the falx cerebri that closes after birth and is rarely observed in the adult population. We describe a unique case of persistent falcine sinus in an adult who presented with venous sinus obstruction.

Intravenous Thrombolysis for Acute Ischemic Stroke

Intravenous recombinant tissue-type plasminogen activator (rtPA, alteplase) is the only drug approved for the treatment of acute ischemic stroke. It should be administered within 3 hours of stroke. There is additional evidence, however, that administration at later times, by means of other methods, is effective. Herein, is a broad review of the knowledge gained and insights created from studies in which thrombolytic treatment was used in patients with stroke.

Developments in endovascular therapy for acute ischemic stroke

Treatment for acute ischemic stroke has for years been frustrated by lack of efficacy. Despite a plethora of seemingly promising treatments from animal research, clinical application never came to fruition. Experience seems to indicate that the only truly effective treatment is the rapid restoration of perfusion to ischemic tissue prior to frank infarction. Unfortunately, every agent designed to achieve this goal met with the same ironic limitation; the ability to dissolve clot was coupled with the risk of causing intracerebral hemorrhage. Accordingly, stroke was addressed primarily through modification of risk factors and rehabilitation of the neurological sequelae. However, following the randomized trial of intravenous tissue-type plasminogen activator (t-PA) sponsored by the National Institutes of Neurological Disorders and Stroke (NINDS) in 1995, the first proven effective therapy for acute stroke became available. The door was finally open to emergency treatment of stroke in the acute phase. Moreover, the positive results of the NINDS trial appear to be independent of age. Nevertheless, intravenous thrombolysis remains ineffective in the majority of patients treated and is withheld from an even larger population because of presentation outside of the 3-hour therapeutic window. As a result, effective therapy is not available for most patients presenting with acute stroke. Recent advancements in the evaluation and treatment of acute ischemic stroke, including intra-arterial thrombolysis, mechanical thrombolysis, and combination therapies, hold significant promise for a larger proportion of patients. New imaging technology may also improve our ability to identify patients with viable brain tissue who may derive the greatest benefit from these therapies.

Natural history of perihematomal edema in patients with hyperacute spontaneous intracerebral hemorrhage

BACKGROUND AND PURPOSE

The natural history of perihematomal edema in human hyperacute spontaneous intracerebral hemorrhage (ICH) has not been well described.

METHODS

This study was a secondary analysis of a previously reported prospective, population-based study of hematoma growth in 142 patients with spontaneous ICH. Patients were first imaged within 3 hours of onset, then 1 and 20 hours later. We excluded patients with anticoagulant use (n=7), underlying aneurysm/vascular malformation (n=9), trauma (n=1), incomplete data (n=20), infratentorial ICH (n=17), and no consent (n=2), leaving an overall study population of 86 patients. From this overall group we further excluded patients with intraventricular extension (n=38), subsequent surgery (n=5), or death (n=2) before 20-hour postbaseline CT. This second, "restricted" analysis group of 41 patients was relatively devoid of clinical or radiological variables likely to confound edema measurement. Absolute and relative edema volumes (edema volume divided by hematoma volume) were descriptively summarized. Correlations between baseline edema volumes and relevant clinical and radiological variables were then performed.

RESULTS

Overall, median absolute edema volume increased from 6.93 to 14.4 cm(3) during the first 24 hours after ICH, and median relative edema volume increased from 0.47 to 0.81. In the restricted group, median absolute edema volume was 7.4 cm(3) at baseline and 11.0 cm(3) at 24 hours after ICH, and median relative edema volume increased from 0.55 to 0.81. Baseline relative edema volume was significantly negatively correlated with subsequent change in relative edema volume from baseline to 20-hour CT (r=0.57, P=0.0002) but was not significantly correlated with other clinical and radiological variables, including hematoma volume or change in hematoma volume.

CONCLUSIONS

Perihematomal edema volume increases by approximately 75% during the first 24 hours after hyperacute spontaneous ICH. Patients with the least amounts of baseline relative edema volume were most likely to develop significant additional amounts of edema during the first 24 hours after spontaneous ICH.

Vein of Galen aneurysmal malformation: diagnosis and treatment of 13 children with extended clinical follow-up

BACKGROUND AND PURPOSE

We herein present our experience in diagnosing and treating 13 children with vein of Galen aneurysmal malformations (VGAM), with an emphasis on possible prognostic indicators, endovascular strategies, factors affecting treatment during the neonatal period, and long-term follow-up. With this review, we hope to identify those factors that have the most significant prognostic value in determining long-term outcomes in children with VGAM.

METHODS

We retrospectively reviewed the radiology studies, hospital charts, and outpatient clinic chart notes (when applicable) of 13 children evaluated and treated for VGAM at a single tertiary care pediatric hospital. Clinical presentation, diagnostic methods, treatment strategies, and outcome were documented for each child. The present neurologic status and level of function of each patient was determined by review of the outpatient charts and direct contact with the clinicians who were conducting the follow-up. Outcome was graded on a 5-point scale, ranging from 0 (death) to 4 (normal), taking into account only neurologic and developmental characteristics.

RESULTS

Eight of 13 patients presented as neonates with congestive heart failure. The other five patients ranged in age from 4 months to 13 years at the time of presentation. The five patients presenting outside of the neonatal period achieved normal or near-normal outcomes. Two of the eight patients presenting during the neonatal period achieved normal or near-normal outcomes, one experienced significant impairment, and the other five died. We were unable to identify significant differences in outcome on the basis of differences in treatment strategies.

CONCLUSION

Our experience confirms that children with VGAM presenting during the neonatal period have a generally much worse prognosis than do those presenting later in childhood. Complicating factors in the management and treatment of these children are discussed in light of their impact on outcome.