Faculty Bibliography

OBJECTIVE: To compare the times to evaluation and thrombolytic treatment of patients treated with a telemedicine-enabled mobile stroke treatment unit (MSTU) vs those among patients brought to the emergency department (ED) via a traditional ambulance. METHODS: We implemented a MSTU with telemedicine at our institution starting July 18, 2014. A vascular neurologist evaluated each patient via telemedicine and a neuroradiologist and vascular neurologist remotely assessed images obtained by the MSTU CT. Data were entered in a prospective registry. The evaluation and treatment of the first 100 MSTU patients (July 18, 2014-November 1, 2014) was compared to a control group of 53 patients brought to the ED via a traditional ambulance in 2014. Times were expressed as medians with their interquartile ranges. RESULTS: Patient and stroke severity characteristics were similar between 100 MSTU and 53 ED control patients (initial NIH Stroke Scale score 6 vs 7, p = 0.679). There was a significant reduction of median alarm-to-CT scan completion times (33 minutes MSTU vs 56 minutes controls, p < 0.0001), median alarm-to-thrombolysis times (55.5 minutes MSTU vs 94 minutes controls, p < 0.0001), median door-to-thrombolysis times (31.5 minutes MSTU vs 58 minutes controls, p = 0.0012), and symptom-onset-to-thrombolysis times (97 minutes MSTU vs 122.5 minutes controls, p = 0.0485). Sixteen patients evaluated on MSTU received thrombolysis, 25% of whom received it within 60 minutes of symptom onset. CONCLUSION: Compared with the traditional ambulance model, telemedicine-enabled ambulance-based thrombolysis resulted in significantly decreased time to imaging and treatment.

Environmental injuries can result in serious neurologic morbidity. This chapter reviews neurologic complications of thermal burns, smoke inhalation, lightning strikes, electric injury, near drowning, decompression illness, as well as heat stroke and accidental hypothermia. Knowing the pathophysiology and clinical presentation of such injuries is essential to proper management of primary and secondary medical complications. This chapter highlights the most frequently encountered neurologic injuries secondary to common environmental hazards, divided into the topics: injuries related to fire, electricity, water, and the extremes of temperature.

BACKGROUND: Ischemic stroke and intracranial hemorrhage (ICH) following left ventricular assist device (LVAD) placement are major causes of morbidity. The incidence and mortality associated with these events stratified by device type have not been systematically explored. METHODS: A systematic review of PubMed was conducted from January 2007 through June 2016 for all English-language articles involving HeartMate II (HMII) and HeartWare LVAD patients. Ischemic stroke and/or ICH incidence (events per patient-year) and associated mortality rates were abstracted for each device type. RESULTS: Of 735 articles reviewed, 48 (11,310 patients) met inclusion criteria (33 HMII, six HeartWare, eight both devices, and one unspecified). The median duration of device support was 112 days (total 13,723 patient-years). Overall, ischemic stroke or ICH occurred in 9.8% (1110 persons and 0.08 events per patient year [EPPY]). Ischemic stroke occurred in a median of 6.0% or 0.06 EPPY (range 0-16% or 0-0.21 EPPY) of HMII patients versus 7.5% or 0.09 EPPY (range 4-17.1% or 0.01-0.94 EPPY) of HeartWare patients. ICH occurred in a median of 3.0% or 0.04 EPPY (range 0-13.5% or 0-0.13 EPPY) of HMII and 8.0% or 0.08 EPPY (range 3-23% or 0.01-0.56 EPPY) of HeartWare patients. The median mortality rate for LVAD-associated ischemic stroke was 31% (HMII: 33%, [range 2.4-75%] and HeartWare: 11.5% [range 3.9-40%]), and the median mortality rate following ICH was 71% (HMII: 75%, [range 3.9-100%] and HeartWare: 44%, [range 3.1-88%]). CONCLUSIONS: Ischemic stroke and ICH are common after LVAD placement, but heterogeneous event rates are reported in the literature. Given the high associated mortality, further prospective study is warranted.

BACKGROUND AND PURPOSE: The mechanism of early brain injury following subarachnoid hemorrhage is not well understood. We aimed to evaluate if cytotoxic and vasogenic edema are contributing factors. MATERIALS AND METHODS: A retrospective analysis was conducted in patients with SAH undergoing diffusion-weighted MR imaging within 72 hours of onset. Apparent diffusion coefficient values derived from DWI were evaluated by using whole-brain histograms and 19 prespecified ROIs in patients with SAH and controls with normal findings on MRI. Cytotoxic edema observed outside the ROIs was assessed in patients with SAH. The average median ADC values were compared between patients with SAH and controls and patients with SAH with mild (Hunt and Hess 1-3) versus severe early brain injury (Hunt and Hess 4-5). RESULTS: We enrolled 33 patients with SAH and 66 controls. The overall average median whole-brain ADC was greater for patients with SAH (808 x 10-6 mm2/s) compared with controls (788 x 10-6 mm2/s, P < .001) and was higher in patients with SAH across ROIs after adjusting for age: cerebral gray matter (826 versus 803 x 10-6 mm2/s, P = .059), cerebral white matter (793 versus 758 x 10-6 mm2/s, P = .023), white matter tracts (797 versus 739 x 10-6 mm2/s, P < .001), and deep gray matter (754 versus 713 x 10-6 mm2/s, P = .016). ADC values trended higher in patients with Hunt and Hess 4-5 versus those with Hunt and Hess 1-3. Early cytotoxic edema was observed in 13 (39%) patients with SAH and was more prevalent in those with severe early brain injury (87.5% of patients with Hunt and Hess 4-5 versus 24.0% of those with Hunt and Hess 1-3, P = .001). CONCLUSIONS: Age-adjusted ADC values were globally increased in patients with SAH compared with controls, even in normal-appearing brain regions, suggesting diffuse vasogenic edema. Cytotoxic edema was also present in patients with SAH and correlated with more severe early brain injury.

BACKGROUND: Stroke is a major cause of mortality after left ventricular assist device (LVAD) placement. METHODS: Prospectively collected data of patients with HeartMate II (n = 332) and HeartWare (n = 70) LVADs from October 21, 2004, to May 19, 2015, were reviewed. Predictors of early (during index hospitalization) and late (post-discharge) ischemic and hemorrhagic stroke and association of stroke subtypes with mortality were assessed. RESULTS: Of 402 patients, 83 strokes occurred in 69 patients (17%; 0.14 events per patient-year [EPPY]): early ischemic stroke in 18/402 (4%; 0.03 EPPY), early hemorrhagic stroke in 11/402 (3%; 0.02 EPPY), late ischemic stroke in 25/402 (6%; 0.04 EPPY) and late hemorrhagic stroke in 29/402 (7%; 0.05 EPPY). Risk of stroke and death among patients with stroke was bimodal with highest risks immediately post-implant and increasing again 9-12 months later. Risk of death declined over time in patients without stroke. Modifiable stroke risk factors varied according to timing and stroke type, including tobacco use, bacteremia, pump thrombosis, pump infection, and hypertension (all p < 0.05). In multivariable analysis, early hemorrhagic stroke (adjusted odds ratio [aOR] 4.3, 95% confidence interval [CI] 1.0-17.8, p = 0.04), late ischemic stroke (aOR 3.2, 95% CI 1.1-9.0, p = 0.03), and late hemorrhagic stroke (aOR 3.7, 95% CI 1.5-9.2, p = 0.005) predicted death, whereas early ischemic stroke did not. CONCLUSIONS: Stroke is a leading cause and predictor of death in patients with LVADs. Risk of stroke and death among patients with stroke is bimodal, with highest risk at time of implant and increasing risk again after 9-12 months. Management of modifiable risk factors may reduce stroke and mortality rates.

BACKGROUND: Although the incidence of subdural hematoma (SDH) has increased in the US in the last decade, limited prospective data exist examining risk factors for poor outcome. METHODS: A prospective, observational study of consecutive SDH patients was conducted from 7/2008 to 11/2011. Baseline clinical data, hospital and surgical course, complications, and imaging data were compared between those with good versus poor 3-month outcomes (modified Rankin Scores [mRS] 0-3 vs. 4-6). A multivariable logistic regression model was constructed to identify independent predictors of poor outcome. RESULTS: 116 SDH patients (18 acute, 56 mixed acute/subacute/chronic, 42 subacute/chronic) were included. At 3 months, 61 (53 %) patients had good outcomes (mRS 0-3) while 55 (47 %) were severely disabled or dead (mRS 4-6). Of those who underwent surgical evacuation, 54/94 (57 %) had good outcomes compared to 7/22 (32 %) who did not (p = 0.030). Patients with mixed acuity or subacute/chronic SDH had significantly better 3-month mRS with surgery (median mRS 1 versus 5 without surgery, p = 0.002) compared to those with only acute SDH (p = 0.494). In multivariable analysis, premorbid mRS, age, admission Glasgow Coma Score, history of smoking, and fever were independent predictors of poor 3-month outcome (all p < 0.05; area under the curve 0.90), while SDH evacuation tended to improve outcomes (adjusted OR 3.90, 95 % CI 0.96-18.9, p = 0.057). CONCLUSIONS: Nearly 50 % of SDH patients were dead or moderate-severely disabled at 3 months. Older age, poor baseline, poor admission neurological status, history of smoking, and fever during hospitalization predicted poor outcomes, while surgical evacuation was associated with improved outcomes among those with mixed acuity or chronic/subacute SDH.

BACKGROUND: Early brain injury (EBI) following aneurysmal subarachnoid hemorrhage (SAH) is an important predictor of poor functional outcome, yet the underlying mechanism is not well understood. Animal studies suggest that platelet activation and inflammation with subsequent microthrombosis and ischemia may be a mechanism of EBI. METHODS: A prospective, hypothesis-driven study of spontaneous, SAH patients and controls was conducted. Platelet activation [thromboelastography maximum amplitude (MA)] and inflammation [C-reactive protein (CRP)] were measured serially over time during the first 72 h following SAH onset. Platelet activation and inflammatory markers were compared between controls and SAH patients with mild [Hunt-Hess (HH) 1-3] versus severe (HH 4-5) EBI. The association of these biomarkers with 3-month functional outcomes was evaluated. RESULTS: We enrolled 127 patients (106 SAH; 21 controls). Platelet activation and CRP increased incrementally with worse EBI/HH grade, and both increased over 72 h (all P < 0.01). Both were higher in severe versus mild EBI (MA 68.9 vs. 64.8 mm, P = 0.001; CRP 12.5 vs. 1.5 mg/L, P = 0.003) and compared to controls (both P < 0.003). Patients with delayed cerebral ischemia (DCI) had more platelet activation (66.6 vs. 64.9 in those without DCI, P = 0.02) within 72 h of ictus. At 3 months, death or severe disability was more likely with higher levels of platelet activation (mRS4-6 OR 1.18, 95 % CI 1.05-1.32, P = 0.007) and CRP (mRS4-6 OR 1.02, 95 % CI 1.00-1.03, P = 0.041). CONCLUSIONS: Platelet activation and inflammation occur acutely after SAH and are associated with worse EBI, DCI and poor 3-month functional outcomes. These markers may provide insight into the mechanism of EBI following SAH.