Phillip M. Meyers

Endovascular therapy of acute ischemic stroke: Report of the Standards of Practice Committee of the Society of NeuroInterventional Surgery

Objective To summarize and classify the evidence for the use of endovascular techniques in the treatment of patients with acute ischemic stroke. Methods Recommendations previously published by the American Heart Association (AHA) (Guidelines for the early management of adults with ischemic stroke (Circulation 2007) and Scientific statement indications for the performance of intracranial endovascular neurointerventional procedures (Circulation 2009)) were vetted and used as a foundation for the current process. Building on this foundation, a critical review of the literature was performed to evaluate evidence supporting the endovascular treatment of acute ischemic stroke. The assessment was based on guidelines for evidence based medicine proposed by the Stroke Council of the AHA and the University of Oxford, Centre for Evidence Based Medicine (CEBM). Procedural safety, technical efficacy and impact on patient outcomes were specifically examined.

Patient radiation exposure during diagnostic and therapeutic interventional neuroradiology procedures

Purpose Increasing in number and complexity, interventional neuroradiology (INR) procedures are becoming an important source of radiation exposure for patients. In accordance with the ALARA principle, radiation exposure during INR procedures should be curtailed as much as possible while reaching successful treatment outcomes. Moreover, the extent of radiation exposure should be one outcome measure used to assess new technologies and procedural efficacy, and training programs should include techniques for exposure limitation. This study provides a methodology and preliminary data to assess radiation exposure during different INR procedure types. Materials and methods All patients undergoing endovascular procedures in two biplanar dedicated neuroangiography suites at a major academic medical center were monitored according to procedure type, pathological indication, fluoroscopy time and machine-generated patient dose estimates between April 2006 and July 2008. Results 1678 patients underwent cerebral arteriography during the study period. Women (62.1%) accounted for the majority of patients, but men (38.9%) were more likely to undergo an interventional procedure than women (32.8%). Diagnostic studies accounted for 64.9% of procedures. Variable exposures were found between diagnostic and interventional procedures. Exposure differed depending on indications for the procedure and procedure type. Conclusion Radiation exposure is an increasingly important consideration in the development of minimally invasive neurological procedures including cerebral angiography and INR. The type of procedure and lesion type allow the practitioner to estimate radiation exposure. Such information informs the clinical decision making process. Normative data should be collected and used for comparison purposes as one measure of technical and procedural success.

Spontaneous delayed proximal migration of enterprise stent after staged treatment of wide-necked basilar aneurysm: technical case report.

OBJECTIVETo document a unique technical issue with a relatively newly released intravascular stent used for adjunctive treatment of wide-necked cerebral aneurysms. CLINICAL PRESENTATIONA 48-year-old woman with a sister who had a large unruptured wide-necked basilar aneurysm underwent screening evaluation that revealed a nearly identical aneurysm. She also harbored small unruptured right superior cerebellar and left anterior cerebral artery aneurysms. INTERVENTIONEndovascular treatment of the 11.5-mm basilar aneurysm was performed in a staged manner. Stent placement was performed first, followed by delayed coil embolization of the aneurysm 9 weeks later. Follow-up angiography at the time of the second procedure revealed significant spontaneous proximal migration of the Enterprise Vascular Reconstruction Device and Delivery System (Cordis Neurovascular, Inc., Miami Lakes, FL) with the distal extent of the device migrating from the right P2 segment into the neck of the aneurysm. Coil embolization was performed despite migration of the vascular reconstruction device. CONCLUSIONThe use of stents in the endovascular treatment of cerebral aneurysms has vastly improved our ability to treat complex lesions. Technical issues remain with these devices, and description of this event may alter the way we use the Enterprise Vascular Reconstruction Device and Delivery System in terms of staging procedures, and when evaluating the particular vascular anatomy of the individual patient with special attention to parent artery vessel size.OBJECTIVE To document a unique technical issue with a relatively newly released intravascular stent used for adjunctive treatment of wide-necked cerebral aneurysms. CLINICAL PRESENTATION A 48-year-old woman with a sister who had a large unruptured wide-necked basilar aneurysm underwent screening evaluation that revealed a nearly identical aneurysm. She also harbored small unruptured right superior cerebellar and left anterior cerebral artery aneurysms. INTERVENTION Endovascular treatment of the 11.5-mm basilar aneurysm was performed in a staged manner. Stent placement was performed first, followed by delayed coil embolization of the aneurysm 9 weeks later. Follow-up angiography at the time of the second procedure revealed significant spontaneous proximal migration of the Enterprise Vascular Reconstruction Device and Delivery System (Cordis Neurovascular, Inc., Miami Lakes, FL) with the distal extent of the device migrating from the right P2 segment into the neck of the aneurysm. Coil embolization was performed despite migration of the vascular reconstruction device. CONCLUSION The use of stents in the endovascular treatment of cerebral aneurysms has vastly improved our ability to treat complex lesions. Technical issues remain with these devices, and description of this event may alter the way we use the Enterprise Vascular Reconstruction Device and Delivery System in terms of staging procedures, and when evaluating the particular vascular anatomy of the individual patient with special attention to parent artery vessel size.

Impact of General Anesthesia on Safety and Outcomes in the Endovascular Arm of Interventional Management of Stroke (IMS) III Trial

Background and Purpose— General anesthesia (GA) for endovascular therapy (EVT) of acute ischemic stroke may be associated with worse outcomes. Methods— The Interventional Management of Stroke III trial randomized patients within 3 hours of acute ischemic stroke onset to intravenous tissue-type plasminogen activator±EVT. GA use within 7 hours of stroke onset was recorded per protocol. Good outcome was defined as 90-day modified Rankin Scale ⩽2. A multivariable analysis adjusting for dichotomized National Institutes of Health Stroke Scale (NIHSS; 8–19 versus ≥20), age, and time from onset to groin puncture was performed. Results— Four hundred thirty-four patients were randomized to EVT, 269 (62%) were treated under local anesthesia and 147 (33.9%) under GA; 18 (4%) were undetermined. The 2 groups were comparable except for median baseline NIHSS (16 local anesthesia versus 18 GA; P<0.0001). The GA group was less likely to achieve a good outcome (adjusted relative risk, 0.68; confidence interval, 0.52–0.90; P=0.0056) and had increased in-hospital mortality (adjusted relative risk, 2.84; confidence interval, 1.65–4.91; P=0.0002). Those with medically indicated GA had worse outcomes (adjusted relative risk, 0.49; confidence interval, 0.30–0.81; P=0.005) and increased mortality (relative risk, 3.93; confidence interval, 2.18–7.10; P<0.0001) with a trend for higher mortality with routine GA. There was no significant difference in the adjusted risks of subarachnoid hemorrhage (P=0.32) or symptomatic intracerebral hemorrhage (P=0.37). Conclusions— GA was associated with worse neurological outcomes and increased mortality in the EVT arm; this was primarily true among patients with medical indications for GA. Relative risk estimates, though not statistically significant, suggest reduced risk for subarachnoid hemorrhage and symptomatic intracerebral hemorrhage under local anesthesia. Although the reasons for these associations are not clear, these data support the use of local anesthesia when possible during EVT. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359424.

Internal Carotid Aplasia/Hypoplasia and Intracranial Saccular Aneurysms: Series of Three New Cases and Systematic Review of the Literature

Background and Purpose. Abnormal arterial flow dynamics and intracranial collateral pathways can be seen in patients with congenital internal carotid artery (ICA) aplasia or hypoplasia. Here we seek to evaluate whether ICA aplasia/hypoplasia is associated with an increased prevalence of intracranial saccular aneurysm relative to carotid rete mirabile. Methods. We combined our experience of three cases with 148 previous publications to form a retrospective series including 132 cases of ICA aplasia, 33 cases of ICA hypoplasia, and 34 cases of carotid rete mirabile. Results. After excluding cases lacking angiograms, ICA aplasia/hypoplasia was more commonly associated with aneurysm (45/158, 27.8%) compared with rete mirabile (2/34, 5.9%). A significantly greater overall aneurysm prevalence was seen among ICA aplasia/hypoplasia patients age 30 years or older (38/101, 36.6%) than in younger individuals (7/48, 14.6%). Conclusions. Intracranial saccular aneurysm is more strongly associated with ICA aplasia/hypoplasia than rete mirabile. An increased aneurysm prevalence among older individuals with ICA aplasia/hypoplasia suggests an acquired etiology. Magnetic resonance angiography (MRA) is recommended in the initial evaluation of ICA aplasia/hypoplasia to evaluate for intracranial saccular aneurysm, particularly after the third decade of life.

Clinical usefulness and safety of routine intraoperative angiography for patients and personnel

OBJECTIVEThe routine use of intraoperative angiography (IA) is still surrounded by controversy. We prospectively performed IAs in consecutive patients undergoing surgery for aneurysms, arteriovenous malformations, and dural arteriovenous fistulae. We calculated the percentage of identified residual pathologies, the cases requiring further surgical intervention, and the complication rates associated with the procedure. We also recorded radiation dose received by personnel during IA for comparison with elective procedures. If our review supported the routine use of IA, recommendations should be tempered by radiation dose to personnel regarding whether or not annual exposure would go beyond recommended limits and whether or not radiation doses indicate a need for specialized operating rooms. METHODSTwo hundred and four consecutive IAs were performed on 191 patients over a 2-year period. Angiographic findings were reviewed retrospectively and noted for additional interventions. Complications related to IA were recorded. Radiation doses received by personnel and fluoroscopy times were compiled from 18 IAs. Mean dose/minutes in intraoperative procedures was compared with mean dose/minutes of a separate cohort of 15 elective angiograms (Students t test). RESULTSTwenty-three percent of IAs revealed relevant findings. Clip repositioning or additional clip placement was performed in 8% of the patients. Resection of residual arteriovenous malformations or additional surgery for residual arteriovenous shunting in dural arteriovenous fistulae was performed in 2% of the patients. Fewer than 1% of the patients received intra-arterial verapamil or topical papaverine. The complication rate was less than 1%. The mean dose per procedure for physicians was 1.018 microsieverts (uSv) versus 0.988 uSv for technicians (P = 0.94). The mean effective dose/minutes in the angiogram suite was 0.9209 uSv/minute versus 1.213 uSv/minute in the operating room (P = 0.33). CONCLUSIONIA identifies a significant number of pertinent findings during open neurovascular surgery, half of which require additional intervention. It is associated with a low complication rate. Radiation dose received by personnel per procedure is negligible. IA radiation dose is not different from dose in the angiogram suite; thus, specialized operating rooms may not be necessary. These data support routine intraoperative angiography in open surgeries for neurovascular disorders.

Society of NeuroInterventional Surgery Standards of Practice: general considerations

This is the first in a set of documents intended to standardize techniques, procedures, and practices in the field of endovascular surgical neuroradiology. Standards are meant to define core practices for peer review, comparison, and improvement. Standards and guidelines also form the basic dialogue, reporting, and recommendations for ongoing practices and future development.

Evidence-based clinical practice for the neurointerventionalist

The field of neurointerventional (NI) surgery has developed in the context of technologic innovation. Many treatments readily provided in 2014 would have been hard to imagine as recently as 10 years ago. The reality of present day NI care is that, while providers, payors, policy makers and patients rely on evidence to guide NI decision-making, the available data are often less robust than participants might desire. In this paper we will explore the fundamentals of evidence-based clinical practice.

Performance and training standards for endovascular ischemic stroke treatment.

OBJECT Gamma Knife surgery (GKS) is gaining popularity in the treatment of patients with acromegaly after transsphenoidal tumor excision. In this paper, the authors examine the efficacy of GKS and predictors for biochemical remission. METHODS The authors retrospectively reviewed data spanning the period 1997–2008 in their hospital Gamma Knife statistics database. Forty patients with a mean age of 64 years (range 19–73 years) underwent GKS for acromegaly during that period. Transsphenoidal subtotal tumor excision had been performed prior to GKS in all these patients, except for 3 deemed to be at high surgical risk. All GKS treatment plans were formulated by the same team that performed the microsurgical procedures. Biochemical remission was defined as a growth hormone (GH) level <2 ng/ml and an insulin-like growth factor–I level that was considered normal with reference to the patients age and sex. The mean follow-up period after radiosurgery was 73.8 months (range 12–132 months). RESULTS Three patients died during the study period of causes unrelated to surgery or GKS. Twenty-nine patients (72.5%) underwent 1 radiosurgery session, and 11 patients (27.5%) required 2 radiosurgery sessions. Among the patients who underwent 1 radiosurgery session, excellent responses (76%–100% reductions in tumor size, GH level, and insulin-like growth factor–I level) were observed in 18 (62%; p < 0.0001), 20 (69%; p < 0.0001), and 5 patients (17%; p = 0.21), respectively. Tumors < 1 cm³ and those with no evidence of cavernous sinus extension were statistically significantly related to a good response in tumor size reduction (p = 0.029 and p = 0.0016, respectively). Subgroup analyses were performed in patients who attained biochemical remission in GH levels; the subgroups included patient sex, patient age, target volume, isodose volume, prescribed dose and isodose, pre-GKS GH level, and evidence of cavernous sinus extension. Only male sex was found to be a statistically significant predictor of good hormone regulation (p = 0.0124). The presence of a cavernous sinus extension was the statistically significant predictor of poor hormone control (p = 0.0011) in our study. CONCLUSIONS Subtotal tumor excision followed by GKS was an effective treatment for acromegaly. Tumors < 1 cm³ and those with no evidence of cavernous sinus extension responded well to treatment. Male sex and absence of cavernous sinus involvement can be regarded as predictors of biochemical remission. (DOI: 10.3171/2010.7.GKS10

Lesion stability characteristics outperform degree of stenosis in predicting outcomes following stenting for symptomatic intracranial atherosclerosis

Background Intracranial atherosclerotic disease (ICAD) causes substantial morbidity and mortality. Treatment decisions have most commonly been driven by the degree of luminal stenosis. This study compares ICAD lesion stability features with percentage stenosis for associations with adverse outcomes following treatment with stents. Materials and methods Retrospective analysis was performed of prospectively maintained procedure logs. Lesions were classified by symptom type as hypoperfusion, non-hypoperfusion, or indeterminate, and pretreatment asymptomatic intervals were noted. Hypoperfusion lesions and indeterminate or non-hypoperfusion lesions with ≥14 days of asymptomatic interval were classified as stable. Percentage stenosis was calculated and compared against these other symptom features for value in predicting technical complication, ischemic stroke, disability, or death at 90 days and 2 years using univariate and multivariate analysis. Results 130 lesions were treated in 124 patients. The only statistically significant percent stenosis finding was lesions with 60–99% stenosis were less likely to have technical complications. In univariate analysis, stroke at 2 years was less common with hypoperfusion and stable lesions. In multivariate analysis, only hypoperfusion status was associated with lower stroke rates at 2 years. Conclusions Lesion stability features, particularly non-hypoperfusion symptomatology, outperform percentage stenosis in predicting outcomes following treatment of ICAD with stents. Further examination is needed to better classify the natural history of ICAD and more precisely classify lesion stability.