Chad W. Washington

Detection and monitoring of vasospasm and delayed cerebral ischemia: a review and assessment of the literature.

Delayed cerebral ischemia (DCI) after subarachnoid hemorrhage can be evaluated using clinical assessment, non-invasive and invasive techniques. An electronic literature search was conducted on English-language articles investigating DCI in human subjects with subarachnoid hemorrhage. A total of 31 relevant papers were identified evaluating the role of clinical assessment, transcranial Doppler, computed tomographic angiography, and computed tomographic perfusion. Clinical assessment by bedside evaluations is limited, especially in patients initially in poorer clinical condition or who are receiving sedative medication for whom deterioration may be more difficult to identify. Transcranial Doppler is a useful screening tool for middle cerebral artery vasospasm, with less utility in evaluating other intracranial vessels. Computed tomographic angiography correlates well with digital subtraction angiography. Computed tomographic perfusion may help predict DCI when used early or identify DCI when used later.

Comparing indocyanine green videoangiography to the gold standard of intraoperative digital subtraction angiography used in aneurysm surgery

OBJECT The purpose of aneurysm surgery is complete aneurysm obliteration while sparing associated arteries. Indocyanine green (ICG) videoangiography is a new technique that allows for real-time evaluation of blood flow in the aneurysm and vessels. The authors performed a retrospective study to compare the accuracy of ICG videoangiography with intraoperative angiography (IA), and determine if ICG videoangiography can be used without follow-up IA. METHODS From June 2007 through September 2009, 155 patients underwent craniotomies for clipping of aneurysms. Operative summaries, angiograms, and operative and ICG videoangiography videos were reviewed. The number, size, and location of aneurysms, the ICG videoangiography and IA findings, and the need for clip adjustment after ICG videoangiography and IA were recorded. Discordance between ICG videoangiography and IA was defined as ICG videoangiography demonstrating aneurysm obliteration and normal vessel flow, but post-IA showing either an aneurysmal remnant and/or vessel occlusion requiring clip adjustment. RESULTS Thirty-two percent of patients (49 of 155) underwent both ICG videoangiography and IA. The post-ICG videoangiography clip adjustment rate was 4.1% (2 of 49). The overall rate of ICG videoangiography-IA agreement was 75.5% (37 of 49) and the ICG videoangiography-IA discordance rate requiring post-IA clip adjustment was 14.3% (7 of 49). Adjustments were due to 3 aneurysmal remnants and 4 vessel occlusions. These adjustments were attributed to obscuration of the residual aneurysm or the affected vessel from the field of view and the presence of dye in the affected vessel via collateral flow. Although not statistically significant, there was a trend for ICG videoangiography-IA discordance requiring clip adjustment to occur in cases involving the anterior communicating artery complex, with an odds ratio of 3.3 for ICG videoangiography-IA discordance in these cases. CONCLUSIONS These results suggest that care should be taken when considering ICG videoangiography as the sole means for intraoperative evaluation of aneurysm clip application. The authors further conclude that IA should remain the gold standard for evaluation during aneurysm surgery. However, a combination of ICG videoangiography and IA may ultimately prove to be the most effective strategy for maximizing the safety and efficacy of aneurysm surgery.

Update on the natural history of cavernous malformations and factors predicting aggressive clinical presentation

Cavernous malformations (CMs) are angiographically occult, low-pressure neurovascular lesions with distinct imaging and clinical characteristics. They present with seizure, neurological compromise due to lesion hemorrhage or expansion, or as incidental findings on neuroimaging studies. Treatment options include conservative therapy, medical management of seizures, surgical intervention for lesion resection, and in select cases stereotactic radiosurgery. Optimal management requires a thorough understanding of the natural history of CMs including consideration of issues such as mode of presentation, lesion location, and genetics that may impact the associated neurological risk. Over the past 2 decades, multiple studies have been published, shedding valuable light on the clinical characteristics and natural history of these malformations. The purpose of this review is to provide the reader with a concise consolidation of this published material such that they may better understand the risks associated with CMs and their implications on patient treatment.

Platelet transfusion: an unnecessary risk for mild traumatic brain injury patients on antiplatelet therapy.

INTRODUCTION To determine whether there is a benefit to platelet transfusion in mild traumatic brain injury (MTBI) patients with intracranial hemorrhage (ICH), taking antiplatelet therapy before hospitalization. MATERIALS AND METHODS The study design retrospectively reviewed patients admitted to a Level I trauma center during a 2-year period with an isolated MTBI (Glasgow Coma Scale score ≥13, ICH seen on a head computed tomographic scan (head computed tomography [HCT]), and taking an antiplatelet agent before hospitalization. HCTs were categorized based on the Marshall Classification, Rotterdam Score, and ICH volume. Hospital records were reviewed noting neurologic, cardiac, respiratory events, and discharge Glasgow Outcome Scale. RESULTS There were 1,101 patients with TBI hospitalized during the 2-year study period. Three hundred twenty-one of these patients had an MTBI with ICH at the time of admission, and from this group, 113 were taking an antiplatelet agent. Only 4 (1.2%) of the 321 patients suffered a neurologic decline. All were gradual in nature, and none required emergent intervention. An analysis of the 113 patients taking antiplatelet agents, comparing patients who were not given a platelet transfusion with those who received a platelet transfusion, found no significant difference in the rate of HCT progression, neurologic decline, or Glasgow Outcome Scale at hospital discharge between the two groups. There was a trend, which was not significant, toward more medical declines in patients who received a platelet transfusion. A further review, analyzing all 321 patients with ICH showed receiving a transfusion of any type (i.e., platelets, fresh frozen plasma, or blood) was a strong predictor of medical decline (p < 0.0001). The odds ratio of having a medical decline after transfusion was 5.8 (95% confidence interval, 1.2-28.2). CONCLUSIONS Platelet transfusion did not improve short-term outcomes after MTBI. Further randomized controlled trials need to be done to truly assess if there is no benefit in platelet transfusion in patients taking antiplatelet agents suffering an MTBI. Because the overall outcome in MTBI patients is favorable, platelet transfusion in these patients may not be indicated.

Modality independent elastography (MIE): a new approach to elasticity imaging

The correlation between tissue stiffness and health is an accepted form of organ disease assessment. As a result, there has been a significant amount of interest in developing methods to image elasticity parameters (i.e., elastography). The modality independent elastography (MIE) method combines a nonlinear optimization framework, computer models of soft-tissue deformation, and standard measures of image similarity to reconstruct elastic property distributions within soft tissue. In this paper, simulation results demonstrate successful elasticity image reconstructions in breast cross-sectional images acquired from magnetic resonance (MR) imaging. Results from phantom experiments illustrate its modality independence by reconstructing elasticity images of the same phantom in both MR and computed tomographic imaging units. Additional results regarding the performance of a new multigrid strategy to MIE and the implementation of a parallel architecture are also presented.

Causes of 30-day readmission after aneurysmal subarachnoid hemorrhage.

OBJECTIVE Hospital readmission is a common but controversial quality measure increasingly used to influence hospital compensation in the US. The objective of this study was to evaluate the causes for 30-day hospital readmission following aneurysmal subarachnoid hemorrhage (SAH) to determine the appropriateness of this performance metric and to identify potential avenues for improved patient care. METHODS The authors retrospectively reviewed the medical records of all patients who received surgical or endovascular treatment for aneurysmal SAH at Barnes-Jewish Hospital between 2003 and 2013. Two senior faculty identified by consensus the primary medical/surgical diagnosis associated with readmission as well as the underlying causes of rehospitalization. RESULTS Among 778 patients treated for aneurysmal SAH, 89 experienced a total of 97 readmission events, yielding a readmission rate of 11.4%. The median time from discharge to readmission was 9 days (interquartile range 3-17.5 days). Actual hydrocephalus or potential concern for hydrocephalus (e.g., headache) was the most frequent diagnosis (26/97, 26.8%), followed by infections (e.g., wound infection [5/97, 5.2%], urinary tract infection [3/97, 3.1%], and pneumonia [3/97, 3.1%]) and thromboembolic events (8/97, 8.2%). In most cases (75/97, 77.3%), we did not identify any treatment lapses contributing to readmission. The most common underlying causes for readmission were unavoidable development of SAH-related pathology (e.g., hydrocephalus; 36/97, 37.1%) and complications related to neurological impairment and immobility (e.g., thromboembolic event despite high-dose chemoprophylaxis; 21/97, 21.6%). The authors determined that 22/97 (22.7%) of the readmissions were likely preventable with alternative management. In these cases, insufficient outpatient medical care (for example, for hyponatremia; 16/97, 16.5%) was the most common shortcoming. CONCLUSIONS Most readmissions after aneurysmal SAH relate to late consequences of hemorrhage, such as hydrocephalus, or medical complications secondary to severe neurological injury. Although a minority of readmissions may potentially be avoided with closer medical follow-up in the transitional care environment, readmission after SAH is an insensitive and likely inappropriate hospital performance metric.

Platelet testing in flow diversion: A review of the evidence

OBJECTIVE Although the use of dual antiplatelet therapy with flow diversion is recommended and commonplace, the testing of platelet inhibition is more controversial. METHODS The authors reviewed the medical literature to establish and describe the physiology of platelet adhesion, the pharmacology of antiplatelet medications, and the mechanisms of the available platelet function tests. Additionally, they present a review of the pertinent neurointerventional and interventional cardiology literature. RESULTS Competing reports in the neurointerventional literature argue for and against the use of routine platelet function testing, with adjustments to the dosage or medications based on the results. The interventional cardiology literature has also wrestled with this dilemma after percutaneous coronary interventions, with conflicting reports of the benefits of platelet function testing. CONCLUSIONS Despite its prevalence, the benefits of platelet function testing prior to flow diversion are unproven. This practice will likely remain controversial until the level of evidence improves through more rigorous testing and reporting.

Predictors of 30-day readmission after aneurysmal subarachnoid hemorrhage: a case-control study.

OBJECTIVE Despite persisting questions regarding its appropriateness, 30-day readmission is an increasingly common quality metric used to influence hospital compensation in the United States. However, there is currently insufficient evidence to identify which patients are at highest risk for readmission after aneurysmal subarachnoid hemorrhage (SAH). The objective of this study was to identify predictors of 30-day readmission after SAH, to focus preventative efforts, and to provide guidance to funding agencies seeking to risk-adjust comparisons among hospitals. METHODS The authors performed a case-control study of 30-day readmission among aneurysmal SAH patients treated at a single center between 2003 and 2013. To control for geographic distance from the hospital and year of treatment, the authors randomly matched each case (30-day readmission) with approximately 2 SAH controls (no readmission) based on home ZIP code and treatment year. They evaluated variables related to patient demographics, socioeconomic characteristics, comorbidities, presentation severity (e.g., Hunt and Hess grade), and clinical course (e.g., need for gastrostomy or tracheostomy, length of stay). Conditional logistic regression was used to identify significant predictors, accounting for the matched design of the study. RESULTS Among 82 SAH patients with unplanned 30-day readmission, the authors matched 78 patients with 153 nonreadmitted controls. Age, demographics, and socioeconomic factors were not associated with readmission. In univariate analysis, multiple variables were significantly associated with readmission, including Hunt and Hess grade (OR 3.0 for Grade IV/V vs I/II), need for gastrostomy placement (OR 2.0), length of hospital stay (OR 1.03 per day), discharge disposition (OR 3.2 for skilled nursing vs other disposition), and Charlson Comorbidity Index (OR 2.3 for score ≥ 2 vs 0). However, the only significant predictor in the multivariate analysis was discharge to a skilled nursing facility (OR 3.2), and the final model was sensitive to criteria used to enter and retain variables. Furthermore, despite the significant association between discharge disposition and readmission, less than 25% of readmitted patients were discharged to a skilled nursing facility. CONCLUSIONS Although discharge disposition remained significant in multivariate analysis, most routinely collected variables appeared to be weak independent predictors of 30-day readmission after SAH. Consequently, hospitals interested in decreasing readmission rates may consider multifaceted, cost-efficient interventions that can be broadly applied to most if not all SAH patients.

Middle cerebral artery bifurcation aneurysms: an anatomic classification scheme for planning optimal surgical strategies.

BACKGROUND: Changing landscapes in neurosurgical training and increasing use of endovascular therapy have led to decreasing exposure in open cerebrovascular neurosurgery. To ensure the effective transition of medical students into competent practitioners, new training paradigms must be developed. OBJECTIVE: Using principles of pattern recognition, we created a classification scheme for middle cerebral artery (MCA) bifurcation aneurysms that allows their categorization into a small number of shape pattern groups. METHODS: Angiographic data from patients with MCA aneurysms between 1995 and 2012 were used to construct 3-dimensional models. Models were then analyzed and compared objectively by assessing the relationship between the aneurysm sac, parent vessel, and branch vessels. Aneurysms were then grouped on the basis of the similarity of their shape patterns in such a way that the in-class similarities were maximized while the total number of categories was minimized. For each category, a proposed clip strategy was developed. RESULTS: From the analysis of 61 MCA bifurcation aneurysms, 4 shape pattern categories were created that allowed the classification of 56 aneurysms (91.8%). The number of aneurysms allotted to each shape cluster was 10 (16.4%) in category 1, 24 (39.3%) in category 2, 7 (11.5%) in category 3, and 15 (24.6%) in category 4. CONCLUSION: This study demonstrates that through the use of anatomic visual cues, MCA bifurcation aneurysms can be grouped into a small number of shape patterns with an associated clip solution. Implementing these principles within current neurosurgery training paradigms can provide a tool that allows more efficient transition from novice to cerebrovascular expert. ABBREVIATIONS: DSA, digital subtraction angiography MCA, middle cerebral artery

Comparing routine versus selective use of intraoperative cerebral angiography in aneurysm surgery: a prospective study

Introduction While the use of intraoperative angiography (IA) has been shown to be a useful adjunct in aneurysm surgery, its routine use remains controversial. Objective We wished to determine if IA is required in all patients undergoing aneurysm surgery (ie, routine IA) or if intraoperative assessment can reliably predict the need for IA (ie, select IA). Methods We prospectively evaluated all patients undergoing craniotomy for aneurysm clipping. In these patients, the treating surgeons were asked to record whether they felt IA was required at two time points: (1) prior to surgery and (2) immediately after clip application but before IA. All patients underwent IA as per the institutional protocol. IA results and the need for post-IA clip adjustments were recorded. Results Of the 200 patients enrolled, 197 were included for analysis. IA was deemed necessary on preoperative assessment in 144 cases (73%) and on post-clip assessment in 116 cases (59%). Post-clip IA demonstrated 47 (24%) positive findings and post-IA clip adjustments were made in 19 of 198 cases (10%). On preoperative assessment, there were four cases where IA was deemed unnecessary, yet post-IA clip adjustment was required, resulting in a sensitivity of 79% and false negative rate of 8%. Regarding post-clip assessment, there were five cases where IA was thought to be unnecessary and clip adjustment was required, resulting in a sensitivity of 73% and false negative rate of 6%. Conclusions The accuracy of a strategy of select IA was not improved by assessing the need for IA immediately after aneurysm clipping versus prior to surgery onset. This suggests that intraoperative assessment regarding the adequacy of aneurysm clip application should be viewed with caution.