Ideal Foundational Requirements for Stroke Program Development and Growth: A Scientific Statement From the American Heart Association.

Stroke center certification has evolved at a rapid pace and is now available at 4 different levels of service in the United States. Although certification standards provide guidance on stroke center process elements, lack of guidance on structural components such as workforce, staffing, and unit operations has resulted in heterogeneous services among hospitals credentialed at the same stroke center level. Such heterogeneity challenges public expectations and transparency about actual service capabilities within American stroke centers and in some cases may foster leniency in credentialing agency certification methods. Standards for other time-dependent diagnoses, including trauma, provide detailed guidance on structural elements that has improved patient triage and resuscitative care while enabling practitioners and administrators to more accurately gauge and plan service development to better support their communities. This scientific statement aims to provide similar structural guidance defined by each level of hospital stroke center services to reduce operational inconsistencies, to foster planning for service development, and to improve the interprofessional care of patients with acute stroke.

How a CT-Direct Protocol at an American Comprehensive Stroke Center Led to Door-to-Needle Times Less Than 30 Minutes.

BACKGROUND AND PURPOSE: The safety and efficacy of intravenous tissue plasminogen activator (IV tPA) following acute ischemic stroke (AIS) is dependent on its timely administration. In 2014, our Comprehensive Stroke Center designed and implemented a computed tomography-Direct protocol to streamline the evaluation process of suspected patients with AIS, with the aim of reducing door-to-needle (DTN) times. The objectives of our study were to describe the protocol development and implementation process, and to compare DTN times and symptomatic intracranial hemorrhage (sICH) rates before and after protocol implementation. METHODS: Data were prospectively collected for patients with AIS receiving IV tPA between January 1, 2010, and May 31, 2015. The DTN times, examined as median times and time treatment windows, and sICH rates were compared pre- and postimplementation. RESULTS: Two hundred ninety-five patients were included in the study. After protocol implementation, median DTN times were significantly reduced (38 vs 28 minutes; P < .001). The distribution of patients treated in the three time treatment windows described below changed significantly, with an increase in patients with DTN times of 30 minutes or less, and a decrease in patients with DTN times 31 to 60 minutes and over 60 minutes (P < .001). There were two cases of sICH prior to implementation and one sICH case postimplementation. CONCLUSIONS: The implementation of a protocol that streamlined the processing of suspected patients with AIS significantly reduced DTN time without negatively impacting patient safety.

Comprehensive analysis of intra-arterial treatment for acute ischemic stroke due to cervical artery dissection.

OBJECTIVE: The safety and efficacy of intra-arterial treatment (IAT) in patients with acute ischemic stroke (AIS) due to cervical artery dissection (CeAD) has not been formally studied. The purpose of this study was twofold: first, describe a large series with CeAD treated with IAT; second, analyze outcomes with CeAD receiving IAT versus (a) CeAD not treated with IAT, (b) CeAD receiving intravenous thrombolysis (IVT) alone, and (c) non-CeAD mechanism of AIS receiving IAT. DESIGN: Demographics, clinical characteristics, treatment, and outcomes were summarized for all CeAD patients treated with IAT from January 2010 to May 2015. Outcomes included favorable 90 day modified Rankin Scale (mRS) score of 0-2, symptomatic intracerebral hemorrhage (sICH), recanalization (Thrombolysis in Cerebral Infarction 2b-3), procedural complications, and mortality. Outcomes were analyzed with χ2 tests and multivariate logistic regression. RESULTS: There were 161 patients with CeAD: 24 were treated with IAT and comprised our target population. Dissections were more common in the internal carotid (n=18) than in the vertebral arteries (n=6). All but one patient had intracranial embolus. IAT techniques included thrombectomy (n=19), IA thrombolysis (n=17), stent (n=14), and angioplasty (n=7). Outcomes included favorable 90 day mRS score of 0-2 in 63%, 4 deaths, 1 sICH, and 3 procedural complications. After adjustment, favorable mRS in our target population was similar to comparison populations: (a) in CeAD, IAT versus no IAT (OR 0.62, p=0.56); (b) In CeAD, IAT versus IVT alone (OR 1.32, p=0.79); and (c) IAT in CeAD versus non-CeAD mechanism of AIS (OR 0.58, p=0.34). CONCLUSIONS: IAT is a valid alternative therapeutic option for AIS caused by CeAD due to the low complication rate and excellent outcomes observed in this study.

A standardized neurointerventional thrombectomy protocol leads to faster recanalization times.

BACKGROUND AND PURPOSE: Intra-arterial therapy (IAT) is most effective when performed rapidly after ischemic stroke onset. However, there are limited performance benchmarks in IAT and there is a scarcity of information on how to structure an effective IAT protocol and its impact on time to treatment. The objective of our study was to detail a standardized IAT protocol, and to assess its influence on time to treatment in ischemic stroke. METHODS: This was a retrospective observational study over 4 years at a comprehensive stroke center. A standardized IAT protocol was implemented in June 2013 that included pre-notifying the stroke team before hospital arrival, defining clinician roles, processing tasks in parallel, and standardizing IAT procedures. Three time metrics were examined and reported as median (IQR) minutes: arrival to CT imaging, CT to groin puncture, and puncture to recanalization. We compared these metrics in patients admitted before implementation (January 2012-May 2013) to patients admitted after (June 2013-December 2015) using Wilcoxon Mann-Whitney tests. RESULTS: 380 patients were included. After the protocol was implemented, there were significant reductions in time from arrival to CT (17 (14-21) vs 13 (11-19) min, p<0.001), CT to puncture (46 (30-82) vs 31 (23-54) min, p<0.001), and puncture to recanalization (65 (33-90) vs 37 (22-65) min, p<0.001). 60% of time was saved during puncture to recanalization. Significant reductions in time were observed during both normal working hours and off-hours. CONCLUSIONS: Implementation of a standardized protocol resulted in a significant reduction in time to recanalization for patients with an ischemic stroke. A standardized IAT protocol decreases time to recanalization when team roles are clearly defined, tasks are processed in parallel, and procedures are standardized.

Light-Driven Processes Control Both Rhodopsin Maturation and Recycling in Mosquito Photoreceptors.

Many invertebrates carry out a daily cycle of shedding and rebuilding of the photoreceptor's photosensitive rhabdomeric membranes. The mosquito Aedes aegypti shows a robust response, losing nearly all Aaop1 rhodopsin from the rhabdomeric membranes during the shedding process at dawn. Here, we made use of Aaop1 antibodies capable of distinguishing newly synthesized, glycosylated rhodopsin from mature nonglycosylated rhodopsin to characterize the fate of Aaop1 during the shedding and rebuilding processes. The rhabdomeric rhodopsin is moved into large cytoplasmic vesicles at dawn and is subsequently degraded during the standard 12 h daytime period. The endocytosed rhodopsin is trafficked back to the photosensitive membranes if animals are shifted back to dark conditions during the morning hours. During the daytime period, small vesicles containing newly synthesized and glycosylated Aaop1 rhodopsin accumulate within the cytoplasm. At dusk, these vesicles are lost as the newly synthesized Aaop1 is converted to the nonglycosylated form and deposited in the rhabdomeres. We demonstrate that light acts though a novel signaling pathway to block rhodopsin maturation, thus inhibiting the deglycosylation and rhabdomeric targeting of newly synthesized Aaop1 rhodopsin. Therefore, light controls two cellular processes responsible for the daily renewal of rhodopsin: rhodopsin endocytosis at dawn and inhibition of rhodopsin maturation until dusk. SIGNIFICANCE STATEMENT: Organisms use multiple strategies to maximize visual capabilities in different light conditions. Many invertebrates show a daily cycle of shedding the photoreceptor's rhabdomeric membranes at dawn and rebuilding these during the following night. We show here that the Aedes aegypti mosquito possesses two distinct light-driven cellular signaling processes for modulating rhodopsin content during this cycle. One of these, endocytosis of rhabdomeric rhodopsin, has been described previously. The second, a light-activated cellular pathway acting to inhibit the anterograde movement of newly synthesized rhodopsin, is revealed here for the first time. The discovery of this cellular signaling pathway controlling a G-protein-coupled receptor is of broad interest due to the prominent role of this receptor family across all areas of neuroscience.

A Four-Year Experience of Symptomatic Intracranial Hemorrhage Following Intravenous Tissue Plasminogen Activator at a Comprehensive Stroke Center.

BACKGROUND: To describe the 4-year experience of symptomatic intracranial hemorrhage (sICH) rate at a high-volume comprehensive stroke center. METHODS: All admitted adult (≥18 years) patients presenting with an ischemic stroke from 2010 to 2013 were included in this study. The primary outcome was sICH, defined as any hemorrhage with neurological deterioration (change in National Institutes of Health Stroke Scale score ≥4) within 36 hours of intravenous tissue plasminogen activator (IV-tPA) treatment, or any hemorrhage resulting in death. Secondary outcomes were in-hospital mortality and having a favorable modified Rankin Scale (mRS) score (≤2). RESULTS: A total of 1925 did not receive intravascular (IV) or intra-arterial (IA) therapy; only 451 received IV therapy; and 175 received both IV and IA therapies. In IV-only patients, the overall rate of sICH was 2.2%; in IV and IA patients, the rate was 5.7%; and in patients who received no therapy, the rate was .4%. The IV-only group had an sICH rate of .9% in 2013. There were no differences in the adjusted odds of dying in the hospital between the study groups. IV-only treatment offered significantly better odds of achieving a favorable functional outcome, compared to no therapy, among patients with moderate stroke severity, whereas IV and IA treatments offered significantly better odds among patients with severe strokes. The odds of achieving a favorable functional outcome by discharge were decreased by 97% if patients suffered an sICH (OR = .03, 95%CI = .004, .19). CONCLUSIONS: Despite an increased risk of sICH with IV-tPA, treatment with IV-tPA continues to be associated with increased odds of a favorable discharge mRS.

Age ≥80 Years Is Not a Contraindication for Intra-Arterial Therapy after Ischemic Stroke.

BACKGROUND: Clinical trials confirmed the safety and efficacy of intra-arterial therapy (IAT) in the management of ischemic stroke. At a community hospital, we compared outcomes in patients aged ≥80 and patients in the age range 55-79 years receiving IAT following ischemic stroke. METHODS: Data were retrospectively abstracted for ischemic stroke patients ≥55 years treated with IAT at an urban comprehensive stroke center between 2010 and 2013. Baseline demographics, incidence of symptomatic intracranial hemorrhage (sICH), in-hospital mortality, discharge modified Rankin scale (mRS) score (favorable ≤2) and improvement in National Institutes of Health Stroke Scale Score (NIHSS; decreased score at discharge) were compared between patients in the age range 55-79 and patients ≥80 years. Data were analyzed using univariate analyses and multivariate logistic regression. RESULTS: IAT was performed in 239 patients with ischemic stroke; 63 (26.4%) were ≥80 years. When compared to patients aged 55-79, the elderly patients were more often female and non-smokers, with a history of atrial fibrillation. No differences were observed in those ≥80 years compared to patients in the age range 55-79 years for sICH (10 vs. 5%, p = 0.23), mortality (24 vs. 18%, p = 0.28), favorable discharge mRS score (13 vs. 19%, p = 0.27), or improvement in NIHSS (83 vs. 92%, p = 0.10). The nonsignificant association of age with the outcomes persisted after adjusting for covariates and when analyzing the subset of patients who received IAT only. CONCLUSIONS: These findings suggest that in a cohort not subject to the criteria of a clinical trial, age ≥80 years should not be a contraindication to IAT.

Expression and light-triggered movement of rhodopsins in the larval visual system of mosquitoes.

During the larval stages, the visual system of the mosquito Aedes aegypti contains five stemmata, often referred to as larval ocelli, positioned laterally on each side of the larval head. Here we show that stemmata contain two photoreceptor types, distinguished by the expression of different rhodopsins. The rhodopsin Aaop3 (GPROP3) is expressed in the majority of the larval photoreceptors. There are two small clusters of photoreceptors located within the satellite and central stemmata that express the rhodopsin Aaop7 (GPROP7) instead of Aaop3. Electroretinogram analysis of transgenic Aaop7 Drosophila indicates that Aaop3 and Aaop7, both classified as long-wavelength rhodopsins, possess similar but not identical spectral properties. Light triggers an extensive translocation of Aaop3 from the photosensitive rhabdoms to the cytoplasmic compartment, whereas light-driven translocation of Aaop7 is limited. The results suggest that these photoreceptor cell types play distinct roles in larval vision. An additional component of the larval visual system is the adult compound eye, which starts to develop at the anterior face of the larval stemmata during the 1st instar stage. The photoreceptors of the developing compound eye show rhodopsin expression during the 4th larval instar stage, consistent with indications from previous reports that the adult compound eye contributes to larval and pupal visual capabilities.

Rhodopsin management during the light-dark cycle of Anopheles gambiae mosquitoes.

The tropical disease vector mosquito Anopheles gambiae possesses 11 rhodopsin genes. Three of these, GPROP1, GPROP3, and GPROP4, encode rhodopsins with >99% sequence identity. We created antisera against these rhodopsins and used immunohistology to show that one or more of these rhodopsins are expressed in the major R1-6 photoreceptor class of the adult A.gambiae eye. Under dark conditions, rhodopsin accumulates within the light-sensitive rhabdomere of the photoreceptor. Light treatment, however, causes extensive movement of rhodopsin to the cytoplasmic compartment. Protein electrophoresis showed that the rhodopsin is present in two different forms. The larger form is an immature species that is deglycosylated during the posttranslational maturation process to generate the smaller, mature form. The immature form is maintained at a constant level regardless of lighting conditions. These results indicate that rhodopsin biosynthesis and movement into the rhabdomere occurs at a constant rate. In contrast, the mature form increases in abundance when animals are placed in dark conditions. Light-triggered internalization and protein degradation counteracts this rhodopsin increase and keeps rhabdomeric rhodopsin levels low in light conditions. The interplay of the constant maturation rate with light-triggered degradation causes rhodopsin to accumulate within the rhabdomere only in dark conditions. Thus, Anopheles photoreceptors possess a mechanism for adjusting light sensitivity through light-dependent control of rhodopsin levels and cellular location.

Rhodopsin coexpression in UV photoreceptors of Aedes aegypti and Anopheles gambiae mosquitoes.

Differential rhodopsin gene expression within specialized R7 photoreceptor cells divides the retinas of Aedes aegypti and Anopheles gambiae mosquitoes into distinct domains. The two species express the rhodopsin orthologs Aaop8 and Agop8, respectively, in a large subset of these R7 photoreceptors that function as ultraviolet receptors. We show here that a divergent subfamily of mosquito rhodopsins, Aaop10 and Agop10, is coexpressed in these R7 photoreceptors. The properties of the A. aegypti Aaop8 and Aaop10 rhodopsins were analyzed by creating transgenic Drosophila expressing these rhodopsins. Electroretinogram recordings, and spectral analysis of head extracts, obtained from the Aaop8 strain confirmed that Aaop8 is an ultraviolet-sensitive rhodopsin. Aaop10 was poorly expressed and capable of eliciting only small and slow light responses in Drosophila photoreceptors, and electroretinogram analysis suggested that it is a long-wavelength rhodopsin with a maximal sensitivity near 500 nm. Thus, coexpression of Aaop10 rhodopsin with Aaop8 rhodopsin has the potential to modify the spectral properties of mosquito ultraviolet receptors. Retention of Op10 rhodopsin family members in the genomes of Drosophila species suggests that this rhodopsin family may play a conserved role in insect vision.

CT perfusion-guided patient selection for endovascular recanalization in acute ischemic stroke: a multicenter study.

BACKGROUND: The treatment of acute ischemic stroke is traditionally centered on time criteria, although recent evidence suggests that physiologic neuroimaging may be useful. In a multicenter study we evaluated the use of CT perfusion, regardless of time from symptom onset, in patients selected for intra-arterial treatment of ischemic stroke. METHODS: Three medical centers retrospectively assessed stroke patients with a National Institute of Health Stroke Scale of ≥ 8, regardless of time from symptom onset. CT perfusion maps were qualitatively assessed. Patients with defined salvageable penumbra underwent intra-arterial revascularization of their occlusion. Functional outcome using the modified Rankin Score (mRS) was recorded. RESULTS: Two hundred and forty-seven patients were selected to undergo intra-arterial treatment based on CT perfusion imaging. The median time from symptom onset to procedure was 6 h. Patients were divided into two groups for analysis: ≤ 8 h and >8 h from symptom onset to endovascular procedure. We found no difference in functional outcome between the two groups (42.8% and 41.9% achieved 90-day mRS ≤ 2, respectively (p=1.0), and 54.9% vs 55.4% (p=1.0) achieved 90-day mRS ≤ 3, respectively). Overall, 48 patients (19.4%) had hemorrhages, of which 20 (8.0%) were symptomatic, with no difference between the groups (p=1.0). CONCLUSIONS: In a multicenter study, we demonstrated similar rates of good functional outcome and intracranial hemorrhage in patients with ischemic stroke when endovascular treatment was performed based on CT perfusion selection rather than time-guided selection. Our findings suggest that physiologic imaging-guided patient selection rather than time for endovascular reperfusion in ischemic stroke may be effective and safe.

Light-mediated control of rhodopsin movement in mosquito photoreceptors.

Multiple mechanisms contribute to a photoreceptor's ability to adapt to ambient light conditions. The mosquito Aedes aegypti expresses the long-wavelength rhodopsin Aaop1 in all R1-R6 photoreceptors and most R8 photoreceptors. These photoreceptors alter the cellular location of Aaop1 and reorganize their photosensitive rhabdomeric membranes on a daily basis. During daylight periods, Aaop1 is excluded from the light-sensitive rhabdomeres and localized to multivesicular bodies (MVBs) within the photoreceptor cytoplasm. In the dark, Aaop1 accumulates in the rhabdomeres and no Aaop1-containing MVBs are present in the cytoplasm. Manipulation of light treatments shows the cellular movement of Aaop1 in and out of the rhabdomere is directly controlled by light. In a separate process, the photoreceptors reduce Aaop1 protein content during a time period spanning from late afternoon into the first 2 h of the dark period. Aaop1 levels then gradually increase through the dark period and remain high following movement of Aaop1 to the cytoplasm at dawn. These results demonstrate that mosquito photoreceptors control rhodopsin availability during the daily light-dark cycle by novel mechanisms not discerned from analysis of traditional invertebrate models. These mechanisms will maximize a photoreceptor's light sensitivity range and therefore may be common in organisms active in low light conditions.

Coexpression of spectrally distinct rhodopsins in Aedes aegypti R7 photoreceptors.

The retina of the mosquito Aedes aegypti can be divided into four regions based on the non-overlapping expression of a UV sensitive Aaop8 rhodopsin and a long wavelength sensitive Aaop2 type rhodopsin in the R7 photoreceptors. We show here that another rhodopsin, Aaop9, is expressed in all R7 photoreceptors and a subset of R8 photoreceptors. In the dorsal region, Aaop9 is expressed in both the cell body and rhabdomere of R7 and R8 cells. In other retinal regions Aaop9 is expressed only in R7 cells, being localized to the R7 rhabdomere in the central and ventral regions and in both the cell body and rhabdomere within the ventral stripe. Within the dorsal-central transition area ommatidia do not show a strict pairing of R7-R8 cell types. Thus, Aaop9 is coexpressed in the two classes of R7 photoreceptors previously distinguished by the non-overlapping expression of Aaop8 and Aaop2 rhodopsins. Electroretinogram analysis of transgenic Drosophila shows that Aaop9 is a short wavelength rhodopsin with an optimal response to 400-450 nm light. The coexpressed Aaop2 rhodopsin has dual wavelength sensitivity of 500-550 nm and near 350 nm in the UV region. As predicted by the spectral properties of each rhodopsin, Drosophila photoreceptors expressing both Aaop9 and Aaop2 rhodopsins exhibit a uniform sensitivity across the broad 350-550 nm light range. We propose that rhodopsin coexpression is an adaptation within the R7 cells to improve visual function in the low-light environments in which Ae. aegypti is active.

Patterned rhodopsin expression in R7 photoreceptors of mosquito retina: Implications for species-specific behavior.

Visual perception of the environment plays an important role in many mosquito behaviors. Characterization of the cellular and molecular components of mosquito vision will provide a basis for understanding these behaviors. A unique feature of the R7 photoreceptors in Aedes aegypti and Anopheles gambiae is the extreme apical projection of their rhabdomeric membrane. We show here that the compound eye of both mosquitoes is divided into specific regions based on nonoverlapping expression of specific rhodopsins in these R7 cells. The R7 cells of the upper dorsal region of both mosquitoes express a long wavelength op2 rhodopsin family member. The lower dorsal hemisphere and upper ventral hemisphere of both mosquitoes express the UV-sensitive op8 rhodopsin. At the lower boundary of this second region, the R7 cells again express the op2 family rhodopsin. In Ae. aegypti, this third region is a horizontal stripe of one to three rows of ommatidia, and op8 is expressed in a fourth region in the lower ventral hemisphere. However, in An. gambiae the op2 family member expression is expanded throughout the lower region in the ventral hemisphere. The overall conserved ommatidial organization and R7 retinal patterning show these two species retain similar visual capabilities. However, the differences within the ventral domain may facilitate species-specific visual behaviors.

Limited role of developmental programmed cell death pathways in Drosophila norpA retinal degeneration.

We examined the role of programmed cell death (PCD) pathways in retinal degeneration caused by a mutation in the norpA gene. norpA degeneration shows morphological hallmarks of programmed cell death, specifically cytoplasmic condensation and engulfment of the dying photoreceptor cells by neighboring retinal pigment cells. However, genetic mosaic analysis of adult photoreceptors lacking rpr, hid, and grim show that these PCD inducers are not required for norpA degeneration. We showed previously that ectopic expression of either rpr or hid triggers rapid PCD in adult photoreceptors, and this is completely suppressed by the coexpression of the baculoviral P35 caspase inhibitor. In contrast, expression of P35 does not suppress norpA retinal degeneration, although a small delay in the rate of degeneration is observed in low light-low temperature conditions. P35 does not alter the morphological characteristics of norpA cell death. Overexpression of the Drosophila inhibitor of apoptosis Diap1 or a dominant-negative form of the Dronc caspase, even when coexpressed with P35, does not dramatically alter the time course of norpA degeneration. These results establish that the pathways responsible for PCD in development do not play a major role in adult retinal degeneration caused by norpA.