CT Perfusion Does Not Modify the Effect of Reperfusion in Patients with Acute Ischemic Stroke Undergoing Endovascular Treatment in the ESCAPE-NA1 Trial.

BACKGROUND AND PURPOSE: Although reperfusion is associated with improved outcomes in patients with acute ischemic stroke undergoing endovascular treatment, many patients still do poorly. We investigated whether CTP modifies the effect of near-complete reperfusion on clinical outcomes, ie, whether poor clinical outcomes despite near-complete reperfusion can be partly or fully explained by CTP findings. MATERIALS AND METHODS: Data are from the Safety and Efficacy of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke (ESCAPE-NA1) trial. Admission CTP was processed using RAPID software, generating relative CBF and CBV volume maps at standard thresholds. CTP lesion volumes were compared in patients with-versus-without near-complete reperfusion. Associations between each CTP metric and clinical outcome (90-day mRS) were tested using multivariable logistic regression, adjusted for baseline imaging and clinical variables. Treatment-effect modification was assessed by introducing CTP lesion volume × reperfusion interaction terms in the models. RESULTS: CTP lesion volumes and reperfusion status were available in 410/1105 patients. CTP lesion volumes were overall larger in patients without near-complete reperfusion, albeit not always statistically significant. Increased CBF <34%, CBV <34%, CBV <38%, and CBV <42% lesion volumes were associated with worse clinical outcome (ordinal mRS) at 90 days. CTP core lesion volumes did not modify the treatment effect of near-complete recanalization on clinical outcome. CONCLUSIONS: CTP did not modify the effect of near-complete reperfusion on clinical outcomes. Thus, CTP cannot explain why some patients with near-complete reperfusion have poor clinical outcomes.

Imaging Triage of Patients with Late-Window (6-24 Hours) Acute Ischemic Stroke: A Comparative Study Using Multiphase CT Angiography versus CT Perfusion.

BACKGROUND AND PURPOSE: The role of collateral imaging in selecting patients for endovascular thrombectomy beyond 6 hours from onset has not been established. To assess the comparative utility of collateral imaging using multiphase CTA in selecting late window patients for EVT. MATERIALS AND METHODS: We used data from a prospective multicenter observational study in which all patients underwent imaging with multiphase CT angiography as well as CTP. Two blinded reviewers evaluated patients' eligibility for endovascular thrombectomy using published collateral imaging (multiphase CTA) criteria compared with CTP using the selection criteria of the Clinical Mismatch in the Triage of Wake Up and Late Presenting Strokes Undergoing Neurointervention with Trevo (DAWN) and Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3 (DEFUSE-3) trials. CTP images were processed using automated commercial software. The outcomes of patients eligible for endovascular thrombectomy according to multiphase CTA, DAWN, or DEFUSE-3 criteria were compared using multivariable logistic regression modeling. Model characteristics were compared using the C-statistic for the receiver operating characteristic curve, the Akaike information criterion, and the Bayesian information criterion. RESULTS: Eighty-six patients presented beyond 6 hours from onset/last known well (median, 9.6 hours; interquartile range, 4.1 hours). Thirty-five patients (40.7%) received endovascular thrombectomy, of whom good functional outcome (90-day mRS, 0-2) was achieved in 16/35 (47%). Collateral-based imaging paradigms significantly modified the treatment effect of endovascular thrombectomy on 90-day mRS 0-2 (P interaction = .007). The multiphase CTA-based regression model best fit the data for the 90-day outcome (C-statistic, 0.86; 95% CI, 0.77-0.94) and was associated with the least information loss (Akaike information criterion, 95.7; Bayesian information criterion, 114.9) compared with CTP-based models. CONCLUSIONS: The collateral-based imaging paradigm using multiphase CTA compares well with CTP in selecting patients for endovascular thrombectomy in the late time window.

Imaging of Patients with Suspected Large-Vessel Occlusion at Primary Stroke Centers: Available Modalities and a Suggested Approach.

The overwhelming benefit of endovascular therapy in patients with large-vessel occlusions suggests that more patients will be screened than treated. Some of those patients will be evaluated first at primary stroke centers; this type of evaluation calls for standardizing the imaging approach to minimize delays in assessing, transferring, and treating these patients. Here, we propose that CT angiography (performed at the same time as head CT) should be the minimum imaging approach for all patients with stroke with suspected large-vessel occlusion presenting to primary stroke centers. We discuss some of the implications of this approach and how to facilitate them.

Extracranial venous drainage patterns in patients with multiple sclerosis and healthy controls.

BACKGROUND AND PURPOSE: CCSVI hypothesizes an association between impaired extracranial venous drainage and MS. Published sonographic criteria for CCSVI are controversial, and no MR imaging data exist to support the CCSVI hypothesis. Our purpose was to evaluate possible differences in the extracranial venous drainage of MS and healthy controls using both TOF and contrast-enhanced TRICKS MRV. MATERIALS AND METHODS: Healthy subjects (n = 20) and patients with MS (n = 19) underwent axial 2D-TOF neck MRV (to assess flattening) and TRICKS MRV (to assess collaterals) at 3T. Two neuroradiologists blinded to cohort status scored IJV flattening and the severity of non-IJV collaterals by using a 4-point qualitative scale (normal = 0, mild = 1, moderate = 2, severe = 3). κ was used to assess reader agreement. Comparisons between groups were performed by using the Wilcoxon rank sum test. The Spearman rank correlation was used to assess the relationship between IJV flattening and collateral scores and, in patients with MS, EDSS scores. RESULTS: The 2 groups were matched for age and sex (MS, 45 ± 8 years, 79% female; healthy controls, 47 ± 10 years, 65% female). Reader agreement for IJV flattening and collateral severity was good (κ = 0.74) and moderate (κ = 0.58), respectively. While IJV flattening was seen in both patients with MS and healthy controls, scores for the patients with MS were significantly higher (P = .002). Despite a trend, there was no significant difference in collateral scores between groups (P = .063). There was a significant positive correlation between flattening and collateral scores (ρ = 0.32, P = .005) and EDSS and flattening scores (ρ = 0.45, P = .004) but not between EDSS and collateral scores (ρ = 0.01, P = .97). CONCLUSIONS: These results indicate that patients with MS have greater IJV flattening and a trend toward more non-IJV collaterals than healthy subjects. The role that this finding plays in the pathogenesis or progression of MS, if any, requires further study.

StarClose vascular closure device: safety and efficacy of deployment and reaccess in a neurointerventional radiology service.

BACKGROUND AND PURPOSE: Obtaining safe and effective closure of the femoral access site following neurointerventional procedures can sometimes be challenging, especially in patients on anti-coagulation or anti-platelet therapy. The purpose of this study was to evaluate the safety and efficacy of a novel percutaneous closure device that employs a nitinol clip-mediated extravascular closure strategy following neurointerventional procedures. MATERIALS AND METHODS: We performed a retrospective review of all patients who underwent neurointerventional procedures at our institution between January 1, 2006 and December 31, 2008. We evaluated the safety and efficacy of the StarClose device in patients undergoing first and repeat procedures. Groin complications were classified as self-limited hematoma, hematoma requiring transfusion, other/minor (pseudoaneurysm, infection), and other/major (vascular complication). RESULTS: StarClose device use was attempted in 281 of 352 cases (79.8%) with success reported in 269 cases (95.7%). Minor and major complications occurred in 0.7% and 0.4% of patients, respectively. There was one major vascular complication. Repeat use was performed in 84 patients with 100% success and a 2.3% minor complication rate. Time to reaccess ranged from 1 to 1036 days (mean, 105 days). CONCLUSIONS: The StarClose device achieves rapid and safe femoral arterial closure in patients, both for primary closure and after reaccess.

Cerebellar pial arteriovenous malformations presenting with medullary venous hypertension: imaging and endovascular treatment.

A patient in their 60s presented with headache and progressive lower extremity weakness over 1 week. Initial MRI was thought to represent venous hypertension secondary to a dural arteriovenous fistula. However, angiography revealed a cerebellar pial arteriovenous malformation with medullary venous hypertension. The imaging and endovascular treatment of this unusual case of a pial cerebellar arteriovenous malformation presenting in that manner is presented.

Inadequate pain relief with labor epidurals: a multivariate analysis of associated factors.

BACKGROUND: Labor epidural analgesia providing inadequate pain relief may cause maternal dissatisfaction and may fail to produce effective anesthesia when topped up for operative delivery. This study looked at factors associated with inadequate labor epidural analgesia. METHODS: Data were prospectively collected from 275 parturients receiving labor epidural analgesia. Pain was assessed 30 min after epidural insertion using a verbal pain scale of 0 to 100. A score of 10 or more was considered to represent inadequate pain relief. Sixteen factors chosen by experienced obstetric anesthesiologists for their association with inadequate labor epidural analgesia were studied. RESULTS: Fifteen parturients were excluded. Forty-four of the remainder (16.9%) experienced inadequate pain relief. Multiparity, history of a previous failure of epidural analgesia, the use of air for loss of resistance, cervical dilatation >7 cm at insertion all had a statistically significant association with inadequate epidural analgesia (P<0.05). Logistic regression showed that cervical dilatation >7 cm, a history of opioid tolerance, a previous failed epidural and insertion of the epidural by a trainee anesthesiologist increased the odds ratio for inadequate pain relief. CONCLUSIONS: The final model correctly classified 93% of the epidurals that provided effective analgesia but classified only 9.3% of those providing inadequate pain relief. This information can be used to develop a predictive score and change practice resulting in fewer inadequate epidurals.

Dehydroascorbic acid, a blood-brain barrier transportable form of vitamin C, mediates potent cerebroprotection in experimental stroke.

Neuronal injury in ischemic stroke is partly mediated by cytotoxic reactive oxygen species. Although the antioxidant ascorbic acid (AA) or vitamin C does not penetrate the blood-brain barrier (BBB), its oxidized form, dehydroascorbic acid (DHA), enters the brain by means of facilitative transport. We hypothesized that i.v. DHA would improve outcome after stroke because of its ability to cross the BBB and augment brain antioxidant levels. Reversible or permanent focal cerebral ischemia was created by intraluminal middle cerebral artery occlusion in mice treated with vehicle, AA, or DHA (40, 250, or 500 mg/kg), either before or after ischemia. Given before ischemia, DHA caused dose-dependent increases in postreperfusion cerebral blood flow, with reductions in neurological deficit and mortality. In reperfused cerebral ischemia, mean infarct volume was reduced from 53% and 59% in vehicle- and AA-treated animals, respectively, to 15% in 250 mg/kg DHA-treated animals (P < 0.05). Similar significant reductions occurred in nonreperfused cerebral ischemia. Delayed postischemic DHA administration after 15 min or 3 h also mediated improved outcomes. DHA (250 mg/kg or 500 mg/kg) administered at 3 h postischemia reduced infarct volume by 6- to 9-fold, to only 5% with the highest DHA dose (P < 0.05). In contrast, AA had no effect on infarct volumes, mortality, or neurological deficits. No differences in the incidence of intracerebral hemorrhage occurred. Unlike exogenous AA, DHA confers in vivo, dose-dependent neuroprotection in reperfused and nonreperfused cerebral ischemia at clinically relevant times. As a naturally occurring interconvertible form of AA with BBB permeability, DHA represents a promising pharmacological therapy for stroke based on its effects in this model of cerebral ischemia.

Postischemic cerebrovascular E-selectin expression mediates tissue injury in murine stroke.

BACKGROUND AND PURPOSE: Although the deleterious role of several proinflammatory mediators, including P-selectin, in reperfused stroke is well established, the role of E-selectin has not been fully characterized. METHODS: E-selectin mRNA expression was studied at 4, 10, and 24 hours after reperfusion with reverse transcription and polymerase chain reaction in mice (n=18) subjected to transient intraluminal middle cerebral artery occlusion (MCAO). Mice received intravenous injection with anti-E-selectin monoclonal antibody (10, 35, or 50 microg), nonimmune IgG, or vehicle immediately before MCAO and 90 minutes later (n=85). Others received anti-E-selectin antibody 3 or 6 hours after MCAO (n=32). Myeloperoxidase activity was measured in sham-operated mice and after 10 hours of reperfusion in saline-, nonimmune IgG-, or anti-E-selectin IgG-treated cohorts (n=17). Serial cerebral blood flow was measured with laser-Doppler flowmetry, and outcomes were assessed by neurological deficits and infarct volumes with the use of planimetric analysis of triphenyltetrazolium chloride-stained sections. RESULTS: Upregulated E-selectin expression occurred in the ischemic cerebral vasculature within 4 hours of reperfusion and persisted for 24 hours. Anti-E-selectin antibody increased ischemic cortical cerebral blood flow up to 2.6-fold (P:<0.05). In addition to dose-dependent reductions in neurological deficits (P:<0.05), mortality, and infarct volumes (P:<0.01 for 35 and 50 microg), anti-E-selectin treatment reduced cerebral neutrophil accumulation (P:<0.05) and was neuroprotective even if delayed until 3 hours after ischemia (P:<0. 05). CONCLUSIONS: These findings establish a functional role for E-selectin in the pathogenesis of tissue injury after cerebral ischemia and reperfusion and suggest that E-selectin blockade may be clinically useful in the treatment of reperfused stroke.

Anesthetic considerations in abdominal aortic surgery.

Contributions of the anesthetist to the management of patients requiring abdominal aortic surgery must complement the roles of the cardiologist and vascular surgeon. Identification of risk factors and assessment of the degree of functional impairment of vital organs allows the anesthetist the best opportunity to provide the vascular patient with as stress-free a surgical experience as possible. Patient profiles, monitoring, induction and maintenance phases in the administration of the anesthetic, and concerns of the early postoperative period are discussed from the anesthetist's perspective. General principles are emphasized. Specific details of assessment and management must be guided by local experience and resources.