Comparison of balloon guide catheter versus non-balloon guide catheter for mechanical thrombectomy in patients with distal medium vessel occlusion

BACKGROUND

Several studies have established the safety and efficacy of balloon guide catheters (BGCs) for large vessel occlusions. However, the utility of BGCs remains largely unexplored for distal medium vessel occlusions (DMVOs). In this study, we aim to compare the outcomes of BGC vs. Non-BGC in patients undergoing mechanical thrombectomy (MT) for DMVO.

METHOD

This retrospective study from the Stroke Thrombectomy and Aneurysm Registry (STAR) encompassed adult patients with acute anterior cerebral artery, posterior cerebral artery, and middle cerebral artery-M2-3-4 occlusions. Procedure times, safety, recanalization, and neurological outcomes were compared between the two groups, with subgroup analysis based on first-line thrombectomy techniques.

RESULTS

A total of 1508 patients were included, with 231 patients (15.3%) in the BGC group and 1277 patients (84.7%) in the non-BGC group. The BGC group had a lower modified Thrombolysis in Cerebral Infarction (mTICI) score ≥2C (43.2% vs 52.7%, P=0.01), longer time from puncture to intracranial access (15 vs 8 min, P<0.01), and from puncture to final recanalization (97 vs 34 min, P<0.01). In the Solumbra subgroup, the first pass effect (FPE) rate was lower in the BGC group (17.4% vs 30.7%, P=0.03). Regarding clinical outcomes, the BGC group had a lower rate of distal embolization (8.8% vs 14.9%, P=0.03).

CONCLUSION

Our study found that use of BGC in patients with DMVO was associated with lower mTICI scores, decreased FPE rates, reduced distal embolization, and longer procedure times.

Comparison between transradial and transfemoral mechanical thrombectomy for ICA and M1 occlusions: insights from the Stroke Thrombectomy and Aneurysm Registry (STAR)

BACKGROUND

The role for the transradial approach for mechanical thrombectomy is controversial. We sought to compare transradial and transfemoral mechanical thrombectomy in a large multicenter database of acute ischemic stroke.

METHODS

The prospectively maintained Stroke Thrombectomy and Aneurysm Registry (STAR) was reviewed for patients who underwent mechanical thrombectomy for an internal carotid artery (ICA) or middle cerebral artery M1 occlusion. Multivariate regression analyses were performed to assess outcomes including reperfusion time, symptomatic intracerebral hemorrhage (ICH), distal embolization, and functional outcomes.

RESULTS

A total of 2258 cases, 1976 via the transfemoral approach and 282 via the transradial approach, were included. Radial access was associated with shorter reperfusion time (34.1 min vs 43.6 min, P=0.001) with similar rates of Thrombolysis in Cerebral Infarction (TICI) 2B or greater reperfusion (87.9% vs 88.1%, P=0.246). Patients treated via a transradial approach were more likely to achieve at least TICI 2C (59.6% vs 54.7%, P=0.001) and TICI 3 reperfusion (50.0% vs 46.2%, P=0.001), and had shorter lengths of stay (mean 9.2 days vs 10.2, P<0.001). Patients treated transradially had a lower rate of symptomatic ICH (8.0% vs 9.4%, P=0.047) but a higher rate of distal embolization (23.0% vs 7.1%, P<0.001). There were no significant differences in functional outcome at 90 days between the two groups.

CONCLUSIONS

Radial and femoral thrombectomy resulted in similar clinical outcomes. In multivariate analysis, the radial approach had improved revascularization rates, fewer cases of symptomatic ICH, and faster reperfusion times, but higher rates of distal emboli. Further studies on the optimal approach are necessary based on patient and disease characteristics.

Mechanical thrombectomy for large vessel occlusion strokes beyond 24 hours

BACKGROUND

Recent clinical trials have shown that mechanical thrombectomy is superior to medical management for large vessel occlusion for up to 24 hours from onset. Our objective is to examine the safety and efficacy of thrombectomy beyond the standard of care window.

METHODS

A retrospective review was undertaken of the multicenter Stroke Thrombectomy and Aneurysm Registry (STAR). We identified patients who underwent mechanical thrombectomy for large vessel occlusion beyond 24 hours. We selected a matched control group from patients who underwent thrombectomy in the 6-24-hour window. We used functional independence at 3 months as our primary outcome measure.

RESULTS

We identified 121 patients who underwent thrombectomy beyond 24 hours and 1824 in the 6-24-hour window. We selected a 2:1 matched group of patients with thrombectomy 6-24 hours as a comparison group. Patients undergoing thrombectomy beyond 24 hours were less likely to be independent at 90 days (18 (18.8%) vs 73 (34.9%), P=0.005). They had higher odds of mortality at 90 days in the adjusted analysis (OR 2.34, P=0.023). Symptomatic intracerebral hemorrhage and other complications were similar in the two groups. In a multivariate analysis only lower number of attempts was associated with good outcomes (OR 0.27, P=0.022).

CONCLUSIONS

Mechanical thrombectomy beyond 24 hours appears to be safe and tolerable with no more hemorrhages or complications compared with standard of care thrombectomy. Outcomes and mortality in this time window are worse compared with an earlier time window, but the rates of good outcomes may justify this therapy in selected patients.

Outcomes of mechanical thrombectomy in stroke patients with extreme large infarction core

BACKGROUND

Recent clinical trials have demonstrated that patients with large vessel occlusion (LVO) and large infarction core may still benefit from mechanical thrombectomy (MT). In this study, we evaluate outcomes of MT in LVO patients presenting with extremely large infarction core Alberta Stroke Program Early CT Score (ASPECTS 0-2).

METHODS

Data from the Stroke Thrombectomy and Aneurysm Registry (STAR) was interrogated. We identified thrombectomy patients presenting with an occlusion in the intracranial internal carotid artery (ICA) or M1 segment of the middle cerebral artery and extremely large infarction core (ASPECTS 0-2). A favorable outcome was defined by achieving a modified Rankin scale of 0-3 at 90 days post-MT. Successful recanalization was defined by achieving a modified Thrombolysis In Cerebral Ischemia (mTICI) score ≥2B.

RESULTS

We identified 58 patients who presented with ASPECTS 0-2 and underwent MT . Median age was 70.0 (59.0-78.0) years, 45.1% were females, and 202 (36.3%) patients received intravenous tissue plasminogen activator. There was no difference regarding the location of the occlusion (p=0.57). Aspiration thrombectomy was performed in 268 (54.6%) patients and stent retriever was used in 70 (14.3%) patients. In patients presenting with ASPECTS 0-2 the mortality rate was 4.5%, 27.9% had mRS 0-3 at day 90, 66.67% ≥70 years of age had mRS of 5-6 at day 90. On multivariable analysis, age, National Institutes of Health Stroke Scale on admission, and successful recanalization (mTICI ≥2B) were independently associated with favorable outcomes.

CONCLUSIONS

This multicentered, retrospective cohort study suggests that MT may be beneficial in a select group of patients with ASPECTS 0-2.

Mechanical thrombectomy for the treatment of primary and secondary anterior cerebral artery occlusions: insights from STAR

BACKGROUND

The safety and efficacy of mechanical thrombectomy (MT) for the treatment of acute anterior cerebral artery (ACA) occlusions have not clearly been delineated. Outcomes may be impacted based on whether the occlusion is isolated to the ACA (primary ACA occlusion) or occurs in conjunction with other cerebral arteries (secondary).

METHODS

We performed a retrospective review of the multicenter Stroke Thrombectomy and Aneurysm (STAR) database. All patients with MT-treated primary or secondary ACA occlusions were included. Baseline characteristics, procedural outcomes, complications, and clinical outcomes were collected. Primary and secondary ACA occlusions were compared using the Mann-Whitney U test and Kruskal-Willis test for continuous variables and the χ2 test for categorical variables.

RESULTS

The study cohort comprised 238 patients with ACA occlusions (49.2% female, median (SD) age 65.6 (16.7) years). The overall rate of successful recanalization was 75%, 90-day good functional outcome was 23%, and 90-day mortality was 35%. There were 44 patients with a primary ACA occlusion and 194 patients with a secondary ACA occlusion. When adjusted for baseline variables, the rates of successful recanalization (68% vs 76%, P=0.27), 90-day good functional outcome (41% vs 19%, P=0.38), and mortality at 90 days (25% vs 38%, P=0.12) did not differ between primary and secondary ACA occlusion groups.

CONCLUSION

Clinical and procedural outcomes are similar between MT-treated primary and secondary ACA occlusions for select patients. Our findings demonstrate the need for established criteria to determine ideal patient and ACA stroke characteristics amenable to MT treatment.

Predictors of Angiographic Outcome After Failed Thrombectomy for Large Vessel Occlusion: Insights from the Stroke Thrombectomy and Aneurysm Registry

BACKGROUND

Mechanical thrombectomy failure (MTF) occurs in approximately 15% of cases.

OBJECTIVE

To investigate factors that predict MTF.

METHODS

This was a retrospective review of prospectively collected data from the Stroke Thrombectomy and Aneurysm Registry. Patients who underwent mechanical thrombectomy (MT) for large vessel occlusion (LVO) were included. Patients were categorized by mechanical thrombectomy success (MTS) (≥mTICI 2b) or MTF (

RESULTS

A total of 6780 patients were included, and 1001 experienced anterior circulation MTF. Patients in the MTF group were older (73 vs 72, P = .044) and had higher poor premorbid modified Rankin Scale (mRS) (10.8% vs 8.4%, P = .017). Onset to puncture time was greater in the MTF group (273 vs 260 min, P = .08). No significant differences were found between the access site, use of balloon guide catheter, frontline technique, or first-pass devices between the MTF and MTS groups. More complications occurred in the MTF group (14% vs 5.8%), including symptomatic intracerebral hemorrhage (9.4% vs 6.1%) and craniectomies (10% vs 2.8%) ( P < .001). On UVA, age, poor pretreatment mRS, increased number of passes, and increased procedure time were associated with MTF. Internal carotid artery, M1, and M2 occlusions had decreased odds of MTF. Poor preprocedure mRS, number of passes, and procedure time remained significant on MVA. A subgroup analysis of posterior circulation LVO revealed that number of passes and total procedure time correlated with increased odds of MTF ( P < .001) while rescue stenting was associated with less odds of MTF (odds ratio 0.20, 95% CI 0.06-0.63). Number of passes remained significant on MVA of posterior circulation occlusion subgroup analysis.

CONCLUSION

Anterior circulation MTF is associated with more complications and worse outcomes. No differences were found between techniques or devises used for the first pass during MT. Rescue intracranial stenting may decrease the likelihood of MTF for posterior circulation MT.

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Key Words Collapse

MESH Headings

• Humans
• Stroke/surgery
• Thrombectomy/methods
• Cerebral Hemorrhage
• Retrospective Studies
• Aneurysm
• Registries
• Treatment Outcome
• Brain Ischemia/therapy

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Grants Collapse

Abstract P500: Outcomes of Mechanical Thrombectomy in Patients With Low Aspects: Insights From Star

Introduction: Patients with poor baseline images were excluded from most clinical trials so the data about whether these patients could benefit from MT remains unknown. In this study, we aim to investigate the safety and efficacy of MT in patients with large vessel occlusion (LVO) and large core infarct (LCI).

Methods: The Stroke Thrombectomy and Aneurysm Registry (STAR) was interrogated. We included thrombectomy patients presenting with LVO within 24 hours and with a LCI as defined by Alberta Stroke Program Early CT Score (ASPECTS) < 6. Patients presenting within 6 hours of last known normal (LKN) were considered in the early window and patients presenting after 6 hours were considered in the late window. 90-day outcomes were assessed. We used a logistic regression model to assess the factors associated with good 90-day outcome in patients in the early and late windows.

Results: 144 patients were included in this study (table). Median age was 69 and 92 (64%) patients were treated in the early MT window. ICA was the most common site of occlusion (48.6%) and ADAPT was used in 34.7%. Admission NIHSS was 17.5. Successful recanalization (TICI>2b) was achieved in 84.7% and median procedure time was 54 minutes. sICH hemorrhage was observed in 22 (15.3%). Median mRS was 4 at 90 days. Favorable outcome was observed in 41 patients (28.5%) and mortality occurred in in 59 (41%). There was no difference in 90-day functional outcome between patients in early and late windows. In patients presenting in the early window, age (aOR=0.905, p=0.0002) and baseline NIHSS (aOR=0.909, p=0.0423) were independently associated with 90-day outcome. In patients presenting in the late window, only age (aOR=0.934, p=0.0069) was independently associated with good outcome.

Conclusion: More than one in four patients presenting with ASPECTS<6 may achieve functional independence at 90-day following MT. Patient age remains the main predictor of 90-day outcome in patients with low ASPECTS in both late and early windows.

Indocyanine green angiography in the surgical management of cerebral arteriovenous malformations: lessons learned in 130 consecutive cases

BACKGROUND

Indocyanine green (ICG) angiography is commonly used to map the vascular configuration of cerebral arteriovenous malformations (AVMs) during resection.

OBJECTIVE

To determine whether ICG improves rates of resection and clinical outcomes.

METHODS

A retrospective chart review was done for all patients undergoing resection of an AVM by the senior author (R.F.S.) between 2007 and 2011. Operative reports, hospital records, and radiographic imaging were used to determine the use of ICG, the incidence of residual disease, and clinical outcomes.

RESULTS

A total of 130 cases (56 ICG, 74 non-ICG) were identified. Average AVM grade (2.2 vs 2.4) and size (2.7 vs 2.7 cm) were similar between the ICG and non-ICG groups, respectively. ICG was more often used when the AVM nidus was close to the cortical surface (71.4% vs 17.6%; P = .001) or lobar (82.1% vs 54.1%; P = .008). Eighteen patients (13.8%) were noted to have residual disease. Reoperation rates and change in modified Rankin Scale score were not different between the 2 groups (12.5% vs 14.9%, P = .8; 0.6 vs 0.4, P = .17). There were no ICG-attributable complications.

CONCLUSION

ICG videoangiography is a quick and safe method of intraoperatively mapping the angioarchitecture of superficial AVMs, but it is less helpful for deep-seated lesions. This modality alone does not improve the identification of residual disease or clinical outcomes. Surgeon experience with extensive study of preoperative vascular imaging is paramount to achieving acceptable clinical outcomes. Formal angiography remains the gold standard for the evaluation of AVM obliteration.

Robotic autopositioning of the operating microscope

BACKGROUND

Use of the operating microscope has become pervasive since its introduction to the neurosurgical world. Neuronavigation fused with the operating microscope has allowed accurate correlation of the focal point of the microscope and its location on the downloaded imaging study. However, the robotic ability of the Pentero microscope has not been utilized to orient the angle of the microscope or to change its focal length to hone in on a predefined target.

OBJECTIVE

To report a novel technology that allows automatic positioning of the operating microscope onto a set target and utilization of a planned trajectory, either determined with the StealthStation S7 by using preoperative imaging or intraoperatively with the microscope.

METHODS

By utilizing the current motorized capabilities of the Zeiss OPMI Pentero microscope, a robotic autopositioning feature was developed in collaboration with Surgical Technologies, Medtronic, Inc. (StealthStation S7). The system is currently being tested at the Barrow Neurological Institute.

RESULTS

Three options were developed for automatically positioning the microscope: AutoLock Current Point, Align Parallel to Plan, and Point to Plan Target. These options allow the microscope to pivot around the lesion, hover in a set plane parallel to the determined trajectory, or rotate and point to a set target point, respectively.

CONCLUSION

Integration of automatic microscope positioning into the operative workflow has potential to increase operative efficacy and safety. This technology is best suited for precise trajectories and entry points into deep-seated lesions.

Diagnosis and management of bow hunter's syndrome: 15-year experience at barrow neurological institute

BACKGROUND

Bow hunter's syndrome is a rare vascular phenomenon characterized by insufficiency of the posterior cerebral circulation induced by rotation of the head within normal physiologic range. The neurosurgical literature on evidence-based diagnosis and management of the disease is scarce, and reports are largely limited to case studies.

METHODS

A retrospective chart review was performed on all patients referred to Barrow Neurological Institute during the period 1999-2013 with signs and symptoms that were possibly indicative of bow hunter's syndrome. Demographic data from patient charts were collected, and the patients' imaging studies were reviewed.

RESULTS

There were 14 patients referred to Barrow Neurological Institute with symptoms concerning for bow hunter's syndrome, and 11 of these patients were confirmed to have dynamic vertebral artery compression on angiography. The location of compression was centered on C1-2 (50%) or C5-7 (50%). The compressed vertebral artery was typically the left artery (72.7%), and in 54.5% of cases, rotation of the head to the contralateral side produced symptomatic dynamic compression. Surgical decompression, via either an anterior (44.4%) or a posterior (55.6%) approach, was eventually performed in 9 patients. Decompression alone was performed in all cases; however, 1 patient developed cervical instability requiring an anterior cervical instrumented fusion 5 years later.

CONCLUSIONS

Decompression without fusion is a safe, reliable surgical option in patients with bow hunter's syndrome. Decompression is performed via a posterior approach for atlantoaxial vertebral artery compression and via an anterior approach for subaxial compression. Long-term complications include cervical instability, which may necessitate internal fixation and fusion.

The dilemma of early postoperative magnetic resonance imaging: when efficiency compromises accuracy: case report

BACKGROUND AND IMPORTANCE

Postoperative magnetic resonance imaging (MRI) is critical to the clinical decision-making process for patients undergoing resection of intracranial tumors. The accuracy of immediate postoperative MRI in determining the presence of residual disease following intracranial tumor resection, however, has not been studied.

CLINICAL PRESENTATION

A 57-year-old man underwent an uncomplicated retrosigmoid craniotomy for the resection of a cystic vestibular schwannoma. Immediate gadolinium-enhanced postoperative MRI, performed within 1.5 hours of surgery, was notable for a plaquelike, lobular, avidly enhancing collection with MRI characteristics consistent with fluid density extending from the porus acusticus into the cerebellopontine angle. This anomalous lesion disappeared upon repeat imaging 48 hours later, and the patient had no attributable clinical sequelae. He was discharged home without issues within 12 hours of repeat imaging.

CONCLUSION

We demonstrate here that immediate postoperative, gadolinium-enhanced MRI scans after tumor resection may result in avid enhancement in the region of surgical manipulation, likely due to leakage of gadolinium chelates into the subarachnoid space from residual compromise of the blood-brain barrier immediately following surgical manipulation. Early imaging is no longer routinely performed at our institution unless otherwise clinically indicated.

ABBREVIATIONS

FLAIR, fluid-attenuated inversion recoveryIAC, internal auditory canal.

Contralateral Interhemispheric Approach to Deep-Seated Cavernous Malformations

BACKGROUND:

Deep-seated periventricular cavernous malformations of the basal ganglia or thalamus can be approached via an interhemispheric craniotomy.

OBJECTIVE:

To determine surgical efficacy and clinical outcomes of the contralateral interhemispheric approach.

METHODS:

Retrospective chart review was performed on patients undergoing an interhemispheric approach for the resection of deep-seated cavernous malformation by the senior author (R.F.S.) between 2005 and 2013. Demographic data and clinical outcomes were reviewed. Pre- and postoperative imaging were analyzed for lesion location, size, associated venous anomaly, proximity to ventricle, and presence of residual.

RESULTS:

Twenty-one patients underwent a contralateral interhemispheric-transventricular approach, 7 patients had a contralateral interhemispheric-transcingulate approach and 3 patients had a contralateral interhemispheric-transchoroidal approach. Mean age was 40.1 years, and the majority were female (58.1%). Mean maximum cavernoma diameter was 1.97 cm, and 43.8% reached the surface of the ventricle. Average follow-up was 8.9 months, with complete resection achieved in 96.8% of patients. At last follow-up, 61.3% of patients remained stable and 29.0% had improved. Of the patients, 6.5% experienced transient weakness that resolved at last follow-up, and 1 patient (3.2%) had short-term memory problems. There were no surgical mortalities.

CONCLUSION:

The contralateral interhemispheric approach is a safe, clinically well tolerated, and surgically efficacious approach to deep-seated cavernomas.

Genealogy of Training in Vascular Neurosurgery

Remarkable advances and changes in the landscape of neurovascular disease have occurred recently. Concurrently, a paradigm shift in training and resident education is underway. This crossroad of unique opportunities and pressures necessitates creative change in the training of future vascular neurosurgeons to allow incorporation of surgical advances, new technology, and supplementary treatment modalities in a setting of reduced work hours and increased public scrutiny. This article discusses the changing landscape in neurovascular disease treatment, followed by the recent changes in resident training, and concludes with our view of the future of training in vascular neurosurgery.

Traumatic, high-cervical, coronal-plane spondyloptosis with unilateral vertebral artery occlusion: treatment using a prophylactic arterial bypass graft, open reduction, and instrumented segmental fusion

The authors present a case of traumatic, complete, high cervical spine injury in a patient with gradual worsening deformity and neck pain while in rigid cervical collar immobilization, ultimately resulting in coronal-plane spondyloptosis. Due to the extent of lateral displacement of the spinal elements, preoperative evaluation included catheter angiography, which revealed complete right vertebral artery (VA) occlusion. A prophylactic arterial bypass graft from the right occipital artery to the extradural right VA was fashioned to augment posterior circulation blood supply prior to reduction and circumferential instrumented fusion. Following surgery, the patient was able to participate in an aggressive rehabilitation program allowing early mobilization, and he ceased to be ventilator-dependent following implantation of a diaphragmatic pacer. The authors review factors leading to progression of this type of injury and suggest technical pearls as well as highlight specific management pitfalls, including operative risks.

Long-term Follow-up of Blister Aneurysms of the Internal Carotid Artery

BACKGROUND:

Blister aneurysms of the internal carotid artery (ICA) are uncommon. There is a paucity of data on the long-term outcomes of patients.

OBJECTIVE:

To review our experience with the treatment of these lesions.

METHODS:

We retrospectively reviewed all aneurysms treated at our institution between 1994 and 2005. Relevant operative notes, radiology reports, and inpatient/outpatient records were reviewed.

RESULTS:

Seventeen patients (3 male, 14 female) with 18 blister aneurysms of the ICA were identified. The mean age was 44.6 years (range, 17–72; median, 42 years). Twelve patients (70.6%) presented with aneurysmal subarachnoid hemorrhage. The mean admission Glasgow Outcome Scale score was 4.3 (range, 2–5; median, 5). All patients were initially treated using microsurgical technique with direct clipping (n = 15; 83.3%) or clip-wrapping with Gore-Tex (n = 3, 16.7%). There were 4 cases of intraoperative rupture, all associated with attempted direct clipping; all 4 cases were successfully clipped. Two cases rebled post-treatment. Both rebleeding episodes were managed with endovascular stenting. Follow-up angiography was available for 14 patients and revealed a new aneurysm adjacent to the site of clipping in 1 patient and in-stent stenosis in 2. At the mean follow-up of 74.5 months (median, 73; range, 7–165), the mean Glasgow Outcome Scale score was 4.6 (range, 2–5; median, 5).

CONCLUSION:

Microsurgical treatment of blister aneurysms of the ICA results in excellent outcome. In the evolution of treating these friable aneurysms, we have modified our clip-wrapping technique and use this technique when direct clipping is not feasible.

Endovascular treatment of fusiform intracranial aneurysms

BACKGROUND AND PURPOSE

Endovascular treatment (EVT) has emerged as an alternative therapeutic strategy for the treatment of intracranial fusiform aneurysms (IFAs), but little is known about the safety and efficacy of deconstructive and reconstructive methods, especially in patients presenting with subarachnoid hemorrhage (SAH). The purpose of this study is to describe the radiological and clinical outcomes in patients with IFAs undergoing EVT.

METHODS

A retrospective analysis was conducted of 18 patients undergoing EVT of IFAs, 13 of whom (72.2%) presented with SAH. Radiological outcomes were characterized by the presence of parent vessel opacification and aneurysmal remnants for patients undergoing deconstructive and reconstructive EVT, respectively. Clinical outcomes were characterized by the Glasgow Outcome Scale. Contingency analysis of factors associated with clinical outcomes in patients with ruptured aneurysms was conducted.

RESULTS

Technical success was achieved in 17 of the 18 patients (94.4%), with 10 (55.6%) undergoing reconstructive EVT and eight (44.4%) undergoing deconstructive EVT. For patients with SAH, favorable clinical outcomes were achieved in 9/13 (69.2%), with 3/6 (50.0%) undergoing reconstructive EVT and 6/7 (85.7%) undergoing deconstructive EVT. Among patients with ruptured aneurysms, only Hunt-Hess grade ≥3 was associated with an unfavorable clinical outcome (p=0.007). Favorable clinical outcomes were seen in all five patients with unruptured aneurysms.

CONCLUSION

Both deconstructive and reconstructive EVT were found to be safe and effective in patients with unruptured aneurysms. Reconstructive EVT may be associated with a higher incidence of poor clinical outcomes in patients presenting with high-grade SAH.

Evidence-based review of primary and secondary ischemic stroke prevention in adults: a neurosurgical perspective

In this paper, the authors' aim is to provide an evidence-based review of primary and secondary ischemic stroke prevention guidelines covering most of the common risk factors and stroke etiologies for the practicing neurosurgeon. The key to stroke prevention is in the identification and treatment of the major risk factors for stroke. These include hypertension, heart disease, diabetes mellitus, dyslipidemia, and tobacco smoking. An updated approach to secondary prevention of stroke in the setting of intracranial and extracranial large vessel atherosclerosis and cardioembolism is provided along with a brief overview of pertinent clinical trials. Novel pharmacological options for prevention of cardioembolic strokes, such as new alternatives to warfarin, are addressed with recommendations for interruption of therapy for elective surgical procedures. In addition, the authors have reviewed the anticoagulation guidelines and the risk of thromboembolic complications of such therapies in the perioperative period, which is an invaluable piece of information for neurosurgeons. Less common etiologies such as arterial dissections and patent foramen ovale are also briefly discussed. Finally, the authors have outlined the quality measures in the Medicare Physician Quality Reporting System and essential guidelines for Primary Stroke Center certification, which have implications for day-to-day neurosurgical practice.

N-butyl 2-cyanoacrylate (n-BCA) embolization of a cerebellar hemangioblastoma

Hemangioblastomas (HBs) are highly vascular tumors whose resection can be associated with significant bleeding. Angioembolization has been used as an adjunct to surgical therapy, but particle embolization of cerebellar HBs has been associated with hemorrhage and resultant morbidity and mortality. We present a case of successful n-BCA embolization of an HB of the cerebellum.

History of the Kleeblattschädel deformity: origin of concepts and evolution of management in the past 50 years

The history and evolution of surgical strategies for the treatment of Kleeblattschädel deformity are not well described in the medical literature. Kleeblattschädel anomaly is one of the most formidable of the craniosynostoses, requiring a multidisciplinary team for surgical treatment. The initial descriptions of this cloverleaf deformity and the evolution of surgical treatment are detailed in the present report. Two illustrative cases of Kleeblattschädel deformity, syndromic and nonsyndromic craniosynostoses treated by the senior authors, are also described along with insights into operative strategies.

Chimerism reveals a role for the streptokinase Beta -domain in nonproteolytic active site formation, substrate, and inhibitor interactions

Streptokinase (SK) and staphylokinase form cofactor-enzyme complexes that promote the degradation of fibrin thrombi by activating human plasminogen. The unique abilities of streptokinase to nonproteolytically activate plasminogen or to alter the interactions of plasmin with substrates and inhibitors may be the result of high affinity binding mediated by the streptokinase beta-domain. To examine this hypothesis, a chimeric streptokinase, SKbetaswap, was created by swapping the SK beta-domain with the homologous beta-domain of Streptococcus uberis Pg activator (SUPA or PauA, SK uberis), a streptokinase that cannot activate human plasminogen. SKbetaswap formed a tight complex with microplasminogen with an affinity comparable with streptokinase. The SKbetaswap-plasmin complex also activated human plasminogen with catalytic efficiencies (k(cat)/K(m) = 16.8 versus 15.2 microm(-1) min(-1)) comparable with streptokinase. However, SKbetaswap was incapable of nonproteolytic active site generation and activated plasminogen by a staphylokinase mechanism. When compared with streptokinase complexes, SKbetaswap-plasmin and SKbetaswap-microplasmin complexes had altered affinities for low molecular weight substrates. The SKbetaswap-plasmin complex also was less resistant than the streptokinase-plasmin complex to inhibition by alpha(2)-antiplasmin and was readily inhibited by soybean trypsin inhibitor. Thus, in addition to mediating high affinity binding to plasmin(ogen), the streptokinase beta-domain is required for nonproteolytic active site generation and specifically modulates the interactions of the complex with substrates and inhibitors.

The mechanism of a bacterial plasminogen activator intermediate between streptokinase and staphylokinase

The therapeutic properties of plasminogen activators are dictated by their mechanism of action. Unlike staphylokinase, a single domain protein, streptokinase, a 3-domain (alpha, beta, and gamma) molecule, nonproteolytically activates human (h)-plasminogen and protects plasmin from inactivation by alpha(2)-antiplasmin. Because a streptokinase-like mechanism was hypothesized to require the streptokinase gamma-domain, we examined the mechanism of action of a novel two-domain (alpha,beta) Streptococcus uberis plasminogen activator (SUPA). Under conditions that quench trace plasmin, SUPA nonproteolytically generated an active site in bovine (b)-plasminogen. SUPA also competitively inhibited the inactivation of plasmin by alpha(2)-antiplasmin. Still, the lag phase in active site generation and plasminogen activation by SUPA was at least 5-fold longer than that of streptokinase. Recombinant streptokinase gamma-domain bound to the b-plasminogen.SUPA complex and significantly reduced these lag phases. The SUPA-b.plasmin complex activated b-plasminogen with kinetic parameters comparable to those of streptokinase for h-plasminogen. The SUPA-b.plasmin complex also activated h-plasminogen but with a lower k(cat) (25-fold) and k(cat)/K(m) (7.9-fold) than SK. We conclude that a gamma-domain is not required for a streptokinase-like activation of b-plasminogen. However, the streptokinase gamma-domain enhances the rates of active site formation in b-plasminogen and this enhancing effect may be required for efficient activation of plasminogen from other species.

Leucine 42 in the fibronectin motif of streptokinase plays a critical role in fibrin-independent plasminogen activation

The NH(2) terminus (residues 1-59) of streptokinase (SK) is a molecular switch that permits fibrin-independent plasminogen activation. Targeted mutations were made in recombinant (r) SK1-59 to identify structural interactions required for this process. Mutagenesis established the functional roles of Phe-37and Glu-39, which were projected to interact with microplasmin in the activator complex. Mutation of Leu-42 (rSK1-59(L42A)), a conserved residue in the SK fibronectin motif that lacks interactions with microplasmin, strongly reduced plasminogen activation (k(cat) decreased 50-fold) but not amidolysis (k(cat) decreased 1.5-fold). Otherwise rSK1-59(L42A) and native rSK1-59 were indistinguishable in several parameters. Both displayed saturable and specific binding to Glu-plasminogen or the remaining SK fragment (rSKDelta59). Similarly rSK1-59 and rSK1-59(L42A) bound simultaneously to two different plasminogen molecules, indicating that both plasminogen binding sites were intact. However, when bound to SKDelta59, rSK1-59(L42A) was less effective than rSK1-59 in restructuring the native conformation of the SK A domain, as detected by conformation-dependent monoclonal antibodies. In the light of previous studies, these data provide evidence that SK1-59 contributes to fibrin-independent plasminogen activation through 1) intermolecular interactions with the plasmin in the activator complex, 2) binding interactions with the plasminogen substrate, and 3) intramolecular interactions that structure the A domain of SK for Pg substrate processing.