Yield of ASPECTS and Collateral CTA Selection for Mechanical Thrombectomy within 6-24 hours from Symptom Onset in a Hub and Spoke System.

BACKGROUND: Recent extended window trials support the benefit of mechanical thrombectomy in anterior circulation large vessel occlusions with clinical-radiographic dissociation. Using trial imaging criteria, 6% were found eligible for MT in the EW in a hub-and-spoke system. We examined the eligibility and outcomes in consecutive extended window-mechanical thrombectomy patients using more pragmatic selection criteria. METHODS: We retrospectively analyzed single-institution data of anterior circulation large vessel occlusions patients presenting between 6-24 h who underwent mechanical thrombectomy based on a priori determined criteria including non-contrast CT head ASPECTS ≥ 6 and/or CTA collateral scores ASITN/SIR 2-4. Primary outcomes consisted of post-mechanical thrombectomy TICI 2b-3 and 3-month modified Rankin scores; safety outcomes consisted of in-hospital mortality and symptomatic intracerebral hemorrhage. RESULTS: 767 consecutive acute ischemic strokes patients presented within the 6-24 hour window, and of these 48 (6%) anterior circulation large vessel occlusions patients underwent mechanical thrombectomy. In this cohort the mean age was 63±17 years, 56% were male, the median NIHSS was 16 [IQR 10-19], the median ASPECTS was 9 (IQR 8-10), and 79% (n=38) had good CTA collaterals. Occlusions were primarily M1 MCA (46%), with 29% tandem occlusions. Successful recanalization (mTICI 2b or 3) was achieved in 73% (n=35), while 6% (n=3) of patients developed symptomatic intracerebral hemorrhage. In-hospital mortality was 25% (n=12) while 40% (n=19) achieved 3-month modified Rankin Scores 0-2. CONCLUSIONS: Our data suggest the use of pragmatic imaging approach of ASPECTS ≥6 with CTA collateral grade in extended time window which is already established in most hospitals.

High-resolution CT with arch/neck/head CT angiography on a mobile stroke unit.

BACKGROUND: Mobile stroke units (MSUs) performance dependability and diagnostic yield of 16-slice, ultra-fast CT with auto-injection angiography (CTA) of the aortic arch/neck/circle of Willis has not been previously reported. METHODS: We performed a prospective observational study of the first-of-its kind MSU equipped with high resolution, 16-slice CT with multiphasic CTA. Field CT/CTA was performed on all suspected stroke patients regardless of symptom severity or resolution. Performance dependability, efficiency and diagnostic yield over 365 days was quantified. RESULTS: 1031 MSU emergency activations occurred; of these, 629 (61%) were disregarded with unrelated diagnoses, and 402 patients transported: 245 (61%) ischemic or hemorrhagic stroke, 17 (4%) transient ischemic attack, 140 (35%) other neurologic emergencies. Total time from non-contrast CT/CTA start to images ready for viewing was 4.0 (IQR 3.5-4.5) min. Hemorrhagic stroke totaled 24 (10%): aneurysmal subarachnoid hemorrhage 3, hemorrhagic infarct 1, and 20 intraparenchymal hemorrhages (median intracerebral hemorrhage score was 2 (IQR 1-3), 4 (20%) spot sign positive). In 221 patients with ischemic stroke, 73 (33%) received alteplase with 31.5% treated within 60 min of onset. CTA revealed large vessel occlusion in 66 patients (30%) of which 9 (14%) were extracranial; 27 (41%) underwent thrombectomy with onset to puncture time averaging 141±90 min (median 112 (IQR 90-139) min) with full emergency department (ED) bypass. No imaging needed to be repeated for image quality; all patients were triaged correctly with no inter-hospital transfer required. CONCLUSIONS: MSU use of advanced imaging including multiphasic head/neck CTA is feasible, offers high LVO yield and enables full ED bypass.

Dual antiplatelet therapy pretreatment in IV thrombolysis for acute ischemic stroke.

OBJECTIVE: We sought to determine the safety and efficacy of IV thrombolysis (IVT) in acute ischemic stroke (AIS) patients with a history of dual antiplatelet therapy pretreatment (DAPP) in a prospective multicenter study. METHODS: We compared the following outcomes between DAPP+ and DAPP- IVT-treated patients before and after propensity score matching (PSM): symptomatic intracranial hemorrhage (sICH), asymptomatic intracranial hemorrhage, favorable functional outcome (modified Rankin Scale score 0-1), and 3-month mortality. RESULTS: Among 790 IVT patients, 58 (7%) were on DAPP before stroke (mean age 68 ± 13 years; 57% men; median NIH Stroke Scale score 8). DAPP+ patients were older with more risk factors compared to DAPP- patients. The rates of sICH were similar between groups (3.4% vs 3.2%). In multivariable analyses adjusting for potential confounders, DAPP was associated with higher odds of asymptomatic intracranial hemorrhage (odds ratio = 3.53, 95% confidence interval: 1.47-8.47; p = 0.005) but also with a higher likelihood of 3-month favorable functional outcome (odds ratio = 2.41, 95% confidence interval: 1.06-5.46; p = 0.035). After propensity score matching, 41 DAPP+ patients were matched to 82 DAPP- patients. The 2 groups did not differ in any of the baseline characteristics or safety and efficacy outcomes. CONCLUSIONS: DAPP is not associated with higher rates of sICH and 3-month mortality following IVT. DAPP should not be used as a reason to withhold IVT in otherwise eligible AIS candidates. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that for IVT-treated patients with AIS, DAPP is not associated with a significantly higher risk of sICH. The study lacked the precision to exclude a potentially meaningful increase in sICH bleeding risk.

Blood pressure levels post mechanical thrombectomy and outcomes in large vessel occlusion strokes.

OBJECTIVE: There are limited data evaluating the effect of post mechanical thrombectomy (MT) blood pressure (BP) levels on early outcomes of patients with large vessel occlusions (LVO). We sought to investigate the association of BP course following MT with early outcomes in LVO. METHODS: Consecutive patients with LVO treated with MT during a 3-year period were evaluated. Hourly systolic BP (SBP) and diastolic BP (DBP) values were recorded for 24 hours following MT and maximum SBP and DBP levels were identified. LVO patients with complete reperfusion following MT were stratified in 3 groups based on post-MT achieved BP goals: <140/90 mm Hg (intensive), <160/90 mm Hg (moderate), and <220/110 mm Hg or <180/105 mm Hg when pretreated with IV thrombolysis (permissive hypertension). Three-month functional independence was defined as modified Rankin Scale score of 0-2. RESULTS: A total of 217 acute ischemic stroke patients with LVO were prospectively evaluated. A 10 mm Hg increment in maximum SBP documented during the first 24 hours post MT was independently (p = 0.001) associated with a lower likelihood of 3-month functional independence (odds ratio [OR] 0.70; 95% confidence interval [CI] 0.56-0.87) and a higher odds of 3-month mortality (OR 1.49; 95% CI 1.18-1.88) after adjusting for potential confounders. In addition, achieving a BP goal of <160/90 mm Hg during the first 24 hours following MT was independently associated with a lower likelihood of 3-month mortality (OR 0.08; 95% CI 0.01-0.54; p = 0.010) in comparison to permissive hypertension. CONCLUSIONS: High maximum SBP levels following MT are independently associated with increased likelihood of 3-month mortality and functional dependence in LVO patients. Moderate BP control is also related to lower odds of 3-month mortality in comparison to permissive hypertension.

Pulmonary Air Embolism: An Infrequent Complication in the Radiology Suite.

BACKGROUND Air embolism can occur in a number of medical-surgical situations. Venous air embolism is frequently lethal when a substantial amount enters the venous circulation rapidly and can lead to significant morbidity if crossover to the systemic arterial circulation occurs. The diagnosis of massive air embolism is usually made on clinical grounds by the development of abrupt hemodynamic compromise. The true incidence, morbidity, and mortality of this event is unknown given the difficulties in diagnosis. CASE REPORT An inadvertent antecubital venous injection of 150 mL of air using a contrast power injector during a computed tomography (CT) is reported. Immediate imaging (CT) showed a significant amount of air in the right atrium and right ventricular cavity, and air mixed with contrast in the main pulmonary artery and proximal divisions of the pulmonary circulation. Patient condition deteriorated requiring mechanical ventilation for 48 hours. Condition improved over the next few days and patient was successfully extubated and discharged home. CONCLUSIONS Air embolism is a rare complication, the potential for this to be life threatening makes prevention and early detection of this condition essential. This condition should be suspected when patients experience sudden onset respiratory distress and/or experience a neurological event in the setting of a known risk factor. Treatment options include Durant's maneuver; left-lateral decubitus, head-down positioning; to decrease air entry into the right ventricle outflow tract, hyperbaric therapy, 100% O2 and supportive care.

Cerebral Microbleeds and Risk of Intracerebral Hemorrhage Post Intravenous Thrombolysis.

BACKGROUND: Stroke patients who have cerebral micro bleeds (CMBs) could be potentially at a greater risk for symptomatic intracerebral hemorrhage (sICH) than those patients without CMBs. The aim of our study was to investigate whether the presence and burden of CMBs are associated with post IVT sICH. METHODS: In this multicenter study, consecutive patients treated with intravenous tissue plasminogen activator were prospectively identified and analyzed. Patients without magnetic resonance imaging (MRI) within 24 hours of treatment were excluded. CMBs were defined as round or oval, hypointense lesions with associated blooming on T2*-weighted MRI up to 10 mm in diameter. Outcome measures included the occurrence of sICH or death. RESULTS: Of 672 patients with IVT (mean age 62 ± 14 years, 52% men, median admission NIHSS: 7 points), 103 patients had CMBs on T2*-MRI. Ten patients had more than 10, whereas the remaining 93 patients had 1-10 CMBs on T2*-MRI. The rates of sICH did not differ between patients with and patients without 1-10 CMBs (5.8% versus 3.5%; P = .27). However, sICH occurred more frequently (P = .0009) in patients with > 10 CMBs (30%, 95% confidence interval [CI] by the adjusted Wald method: 10%-61%). After adjusting for potential confounders, the presence of >10 CMBs on T2*-MRI was independently (P = .0004) associated with a higher likelihood for sICH (odds ratio [OR]:13.4, 95%CI:3.2-55.9). CONCLUSIONS: Our findings indicate an increased risk of sICH after IVT when more than 10 CMBs are present.

Implications of limiting mechanical thrombectomy to patients with emergent large vessel occlusion meeting top tier evidence criteria.

BACKGROUND: Recent guidelines for endovascular management of emergent large vessel occlusion (ELVO) award top tier evidence to the same selective criteria in recent trials. We aimed to understand how guideline adherence would have impacted treatment numbers and outcomes in a cohort of patients from a comprehensive stroke center. METHODS: A retrospective observational study was conducted using consecutive emergent endovascular patients. Mechanical thrombectomy (MT) was performed with stent retrievers or large bore clot aspiration catheters. Procedural outcomes were compared between patients meeting, and those failing to meet, top tier evidence criteria. RESULTS: 126 patients receiving MT from January 2012 to June 2015 were included (age 31-89 years, National Institutes of Health Stroke Scale (NIHSS) score 2-38); 62 (49%) patients would have been excluded if top tier criteria were upheld: pretreatment NIHSS score <6 (10%), Alberta Stroke Program Early CT score <6 (6.5%), premorbid modified Rankin Scale (mRS) score ≥2 (27%), M2 occlusion (10%), posterior circulation (32%), symptom to groin puncture >360 min (58%). 26 (42%) subjects had more than one top tier exclusion. Symptomatic intracerebral hemorrhage (sICH) and systemic hemorrhage rates were similar between the groups. 3 month mortality was 45% in those lacking top tier evidence compared with 26% (p=0.044), and 3 month mRS score 0-2 was 33% versus 46%, respectively (NS). After adjusting for potential confounders, top tier treatment was not associated with neurological improvement during hospitalization (ß -8.2; 95% CI -24.6 to -8.2; p=0.321), 3 month mortality (OR=0.38; 95% CI 0.08 to 1.41), or 3 month favorable mRS (OR=0.97; 95% CI 0.28 to 3.35). CONCLUSIONS: Our study showed that with strict adherence to top tier evidence criteria, half of patients may not be considered for MT. Our data indicate no increased risk of sICH and a potentially higher mortality that is largely due to treatment of patients with basilar occlusions and those treated at an extended time window. Despite this, good functional recovery is possible, and consideration of MT in patients not meeting top tier evidence criteria may be warranted.

Perioperative atrial fibrillation and the long-term risk of ischemic stroke.

IMPORTANCE: Clinically apparent atrial fibrillation increases the risk of ischemic stroke. In contrast, perioperative atrial fibrillation may be viewed as a transient response to physiological stress, and the long-term risk of stroke after perioperative atrial fibrillation is unclear. OBJECTIVE: To examine the association between perioperative atrial fibrillation and the long-term risk of stroke. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study using administrative claims data on patients hospitalized for surgery (as defined by surgical diagnosis related group codes), and discharged alive and free of documented cerebrovascular disease or preexisting atrial fibrillation from nonfederal California acute care hospitals between 2007 and 2011. Patients undergoing cardiac vs other types of surgery were analyzed separately. MAIN OUTCOMES AND MEASURES: Previously validated diagnosis codes were used to identify ischemic strokes after discharge from the index hospitalization for surgery. The primary predictor variable was atrial fibrillation newly diagnosed during the index hospitalization, as defined by previously validated present-on-admission codes. Patients were censored at postdischarge emergency department encounters or hospitalizations with a recorded diagnosis of atrial fibrillation. RESULTS: Of 1,729,360 eligible patients, 24,711 (1.43%; 95% CI, 1.41%-1.45%) had new-onset perioperative atrial fibrillation during the index hospitalization and 13,952 (0.81%; 95% CI, 0.79%-0.82%) experienced a stroke after discharge. At 1 year after hospitalization for cardiac surgery, cumulative rates of stroke were 0.99% (95% CI, 0.81%-1.20%) in those with perioperative atrial fibrillation and 0.83% (95% CI, 0.76%-0.91%) in those without atrial fibrillation. At 1 year after noncardiac surgery, cumulative rates of stroke were 1.47% (95% CI, 1.24%-1.75%) in those with perioperative atrial fibrillation and 0.36% (95% CI, 0.35%-0.37%) in those without atrial fibrillation. In a Cox proportional hazards analysis accounting for potential confounders, perioperative atrial fibrillation was associated with subsequent stroke both after cardiac surgery (hazard ratio, 1.3; 95% CI, 1.1-1.6) and noncardiac surgery (hazard ratio, 2.0; 95% CI, 1.7-2.3). The association was significantly stronger for perioperative atrial fibrillation after noncardiac vs cardiac surgery (P < .001 for interaction). CONCLUSIONS AND RELEVANCE: Among patients hospitalized for surgery, perioperative atrial fibrillation was associated with an increased long-term risk of ischemic stroke, especially following noncardiac surgery.

Neural circuitry underlying the regulation of conditioned fear and its relation to extinction.

Recent efforts to translate basic research to the treatment of clinical disorders have led to a growing interest in exploring mechanisms for diminishing fear. This research has emphasized two approaches: extinction of conditioned fear, examined across species; and cognitive emotion regulation, unique to humans. Here, we sought to examine the similarities and differences in the neural mechanisms underlying these two paradigms for diminishing fear. Using an emotion regulation strategy, we examine the neural mechanisms of regulating conditioned fear using fMRI and compare the resulting activation pattern with that observed during classic extinction. Our results suggest that the lateral PFC regions engaged by cognitive emotion regulation strategies may influence the amygdala, diminishing fear through similar vmPFC connections that are thought to inhibit the amygdala during extinction. These findings further suggest that humans may have developed complex cognition that can aid in regulating emotional responses while utilizing phylogenetically shared mechanisms of extinction.

Temporal lobe epilepsy: a progressive disorder?

Temporal lobe epilepsy (TLE) can be a progressive disorder, potentially resulting in structural damage and a decline of cognitive abilities over time. This is particularly evident in cases that are refractory to medication. This review examines the changes that occur in refractory TLE over time and the factors associated with these changes. Imaging and histologic studies on the brains of patients with TLE reveal anatomic and metabolic changes associated with continued seizures. These changes can impair cognitive and behavioral function. Seizure control may help minimize or prevent these changes.

Learning fears by observing others: the neural systems of social fear transmission.

Classical fear conditioning has been used as a model paradigm to explain fear learning across species. In this paradigm, the amygdala is known to play a critical role. However, classical fear conditioning requires first-hand experience with an aversive event, which may not be how most fears are acquired in humans. It remains to be determined whether the conditioning model can be extended to indirect forms of learning more common in humans. Here we show that fear acquired indirectly through social observation, with no personal experience of the aversive event, engages similar neural mechanisms as fear conditioning. The amygdala was recruited both when subjects observed someone else being submitted to an aversive event, knowing that the same treatment awaited themselves, and when subjects were subsequently placed in an analogous situation. These findings confirm the central role of the amygdala in the acquisition and expression of observational fear learning, and validate the extension of cross-species models of fear conditioning to learning in a human sociocultural context. Our findings also provides new insights into the relationship between learning from, and empathizing with, fearful others. This study suggests that indirectly attained fears may be as powerful as fears originating from direct experiences.

Extinction learning in humans: role of the amygdala and vmPFC.

Understanding how fears are acquired is an important step in translating basic research to the treatment of fear-related disorders. However, understanding how learned fears are diminished may be even more valuable. We explored the neural mechanisms of fear extinction in humans. Studies of extinction in nonhuman animals have focused on two interconnected brain regions: the amygdala and the ventral medial prefrontal cortex (vmPFC). Consistent with animal models suggesting that the amygdala is important for both the acquisition and extinction of conditioned fear, amygdala activation was correlated across subjects with the conditioned response in both acquisition and early extinction. Activation in the vmPFC (subgenual anterior cingulate) was primarily linked to the expression of fear learning during a delayed test of extinction, as might have been expected from studies demonstrating this region is critical for the retention of extinction. These results provide evidence that the mechanisms of extinction learning may be preserved across species.