The Zoom RDL radial access system for neurointervention: An early single-center experience

BACKGROUND

The transradial approach (TRA) for neurointerventional procedures is increasingly being used given its technical feasibility and safety. However, catheter trackability and device deliverability are reported barriers to TRA adoption.

METHODS

This is the first report describing the technical feasibility and performance of using the Zoom RDL Radial Access System (Imperative Care, Inc., Campbell, CA) in 29 patients who underwent neurointerventional procedures from October 2022 to January 2023 in a single-center institution.

RESULTS

Mean age of the study population was 61.9±17.2 years, 79.3% were male (23/29), and 62.1% were black (18/29). The most common procedures were stroke thrombectomy (31.0%, 9/29) and aneurysm embolization (27.6%, 8/29). All the stroke thrombectomy procedures were successfully performed; first-pass effect rate (mTICI≥2 c in one pass) was achieved in 66.7% (6/9) of cases. We used TRA in 86.2% of cases (25/29), including distal radial/snuffbox access in 31.0% (9/29) of cases. The radial diameter was >2 mm for all cases. An intermediate/aspiration catheter was used in 89.7% (26/29) of cases. Access success was achieved in 89.7% of cases (26/29); two cases required conversion from TRA to transfemoral approach (6.9%) and one case required conversion to a different guide catheter (3.4%). There were no access site complications or other Zoom RDL-related complications. One intracerebral hemorrhage, and one procedure-related thrombus were observed.

CONCLUSIONS

The use of Zoom RDL Radial Access System is technically feasible and effective for complex neurointerventional procedures with low complication rates.

The use of PK Papyrus covered coronary stent for carotid reconstruction: an initial institutional experience

BACKGROUND

The use of covered stent grafts for the treatment of carotid rupture is increasingly being used given their ability to preserve the parent artery while simultaneously occluding the fistula or rupture point.

METHODS

This case series describes the technical feasibility of using, and the performance of, the PK Papyrus covered coronary stent (Biotronik, Inc., Lake Oswego, Oregon, USA) in six patients with carotid rupture, including carotid cavernous fistulas, between July 2021 and October 2023 in a single-center institution in the USA.

RESULTS

The median decade of life was 5 (IQR 3) with a 1:1 male-to-female ratio. The majority were black patients (n=5/6, 83.3%). The most common disease pathology was carotid cavernous fistula (n=4/6, 66.7%), followed by traumatic carotid rupture (n=2/6, 33.3%). All the stent embolization procedures were successfully treated with the PK Papyrus covered coronary stent. None of the patients had any recurrence or re-treatment. The number of stents required ranged from 1 to 3. A balloon guide catheter was used in 66.7% of cases (n=4/6). In-hospital mortality was 0.0% (n=0/6). No in-stent thrombosis was observed, but there was one case of cangrelor-associated hemorrhagic stroke conversion. Transfemoral access was used in all cases with one access site complication. Median follow-up time was 1.8 months (IQR 3.5).

CONCLUSIONS

To our knowledge, this is the largest case series in the USA demonstrating the feasibility and safety of using the PK Papyrus covered coronary stent for the treatment of carotid rupture, including carotid cavernous fistulas.

Endovascular Thrombectomy With or Without Thrombolysis for Stroke: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

To this date, whether to administer intravenous thrombolysis (IVT) prior to endovascular thrombectomy (EVT) for stroke patients still stirs some debate. We aimed to systematically update the evidence from randomized trials comparing EVT alone vs EVT with bridging IVT.

Methods

We searched MEDLINE, EMBASE, and the Cochrane Library to identify randomized controlled trials (RCTs) comparing EVT with or without IVT in patients presenting with stroke secondary to a large vessel occlusion. We conducted meta-analyses using random-effects models to compare functional independence, mortality, and symptomatic intracranial hemorrhage (sICH), between EVT and EVT with IVT. We assessed risk of bias using the Cochrane risk-of-bias tool and certainty of evidence for each outcome using the GRADE approach.

Results

Of 11,111 citations, we included 6 studies with a total of 2336 participants. We found low-certainty evidence of possibly a small decrease in the proportion of patients with functional independence (risk difference [RD] -2.0%, 95% CI -5.9% to 2.0%), low-certainty evidence that there is possibly a small increase in mortality (RD 1.0%, 95% CI -2.2% to 4.7%), and moderate-certainty evidence that there is probably a decrease in sICH (RD -1.0%, 95% CI -1.6% to .7%) for patients with EVT alone compared to EVT plus IVT, respectively.

Conclusion

Low-certainty evidence shows that there is possibly a small decrease in functional independence, low-certainty evidence shows that there is possibly a small increase in mortality, and moderate-certainty evidence that there is probably a decrease in sICH for patients with EVT alone compared to EVT plus IVT.

Underlying intracranial atherosclerotic disease is associated with worse outcomes in acute large vessel occlusion undergoing endovascular thrombectomy

BACKGROUND

Data on large vessel occlusion (LVO) management due to intracranial atherosclerotic disease (ICAD) are scarce.

OBJECTIVE

To compare clinical outcomes between patients with ICAD and those without ICAD following mechanical thrombectomy (MT).

METHODS

We performed a retrospective analysis of consecutive patients who underwent MT for LVO in a large academic comprehensive stroke center, and compared in-hospital mortality, 90-day mortality, favorable functional outcome at 90 days, and symptomatic intracranial hemorrhage (ICH) using chi-squared tests and multivariate logistic regression analyses. We defined ICAD as observable plaque at occlusion site post-thrombectomy.

RESULTS

Among 215 patients (mean age 67.1 ± 16.0 years; 60.5% female; 83.6% Black, median NIHSS score 16), ICAD was present in 38 patients (17.7%). Diabetes and dyslipidemia were more common in those with ICAD (57.9% vs. 38.4%, p = 0.027 and 29.0% vs. 14.7%, p = 0.035, respectively). Substantial reperfusion (TICI ≥2b) was achieved less often (84.2% vs. 94.4%, p = 0.031) but symptomatic ICH was also less common in ICAD patients (0% vs. 9.0%, p = 0.081). In-hospital and 90-day mortality were more common (36.8% vs. 15.8%, p = 0.003 and 52.6% vs. 26.6%, p = 0.002, respectively) and favorable functional outcome (mRS 0-2) at 90 days was less common (7.9% vs. 33.9%, p = 0.001) in ICAD patients. After adjusting for prognostic variables, ICAD was independently associated with in-hospital mortality (OR=4.1, 95% CI 1.7-9.7), 90-day mortality (OR=3.7, 95% CI 1.6-8.6), and poor functional outcome at 90 days (OR=5.5, 95% CI 1.6-19.4).

CONCLUSION

Symptomatic ICAD in a predominantly African American cohort is associated with increased odds of mortality and poor functional outcome at 90 days in patients with LVO undergoing MT.

Endovascular thrombectomy with or without thrombolysis bridging in patients with acute ischaemic stroke: protocol for a systematic review, meta-analysis of randomised trials and cost-effectiveness analysis

INTRODUCTION

Current published guidelines and meta-analyses comparing endovascular thrombectomy (EVT) alone versus EVT with bridging intravenous thrombolysis (IVT) suggest that EVT alone is non-inferior to EVT with bridging thrombolysis in achieving favourable functional outcome. Because of this controversy, we aimed to systematically update the evidence and meta-analyse data from randomised trials comparing EVT alone versus EVT with bridging thrombolysis, and performed an economic evaluation comparing both strategies.

METHODS AND ANALYSIS

We will conduct a systematic review of randomised controlled trials comparing EVT with or without bridging thrombolysis in patients presenting with large vessel occlusions. We will identify eligible studies by systematically searching the following databases from inception without any language restrictions: MEDLINE (through Ovid), Embase and the Cochrane Library. The following criteria will be used to assess eligibility for inclusion: (1) adult patients ≥18 years old; (2) randomised patients to EVT alone or to EVT with IVT; and (3) measured outcomes, including functional outcomes, at least 90 days after randomisation. Pairs of reviewers will independently screen the identified articles, extract information and assess the risk of bias of eligible studies. We will use the Cochrane Risk-of-Bias tool to evaluate risk of bias. We will also use the Grading of Recommendations, Assessment, Development and Evaluation approach to assess the certainty in evidence for each outcome. We will then perform an economic evaluation based on the extracted data.

ETHICS AND DISSEMINATION

This systematic review will not require a research ethics approval because no confidential patient data will be used. We will disseminate our findings by publishing the results in a peer-reviewed journal and via presentation at conferences.

PROSPERO REGISTRATION NUMBER

CRD42022315608.

Endovascular thrombectomy for cerebral venous sinus thrombosis using the Penumbra Indigo® Aspiration System

We present a 35-year-old male with ulcerative colitis initially admitted for a flare-up who then presented with altered mental status and was found to have extensive cerebral venous sinus thrombosis on computed tomography imaging. The patient underwent successful partial recanalization of the superior sagittal sinus and bilateral transverse sinuses using the Penumbra Indigo® Aspiration System with improved outcomes. To our knowledge, this is the first reported use of this device in the treatment of cerebral venous sinus thrombosis.

Predictors of Atrial Fibrillation in Patients With Stroke Attributed to Large- or Small-Vessel Disease: A Prespecified Secondary Analysis of the STROKE AF Randomized Clinical Trial

Importance

The Stroke of Known Cause and Underlying Atrial Fibrillation (STROKE AF) trial found that approximately 1 in 8 patients with recent ischemic stroke attributed to large- or small-vessel disease had poststroke atrial fibrillation (AF) detected by an insertable cardiac monitor (ICM) at 12 months. Identifying predictors of AF could be useful when considering an ICM in routine poststroke clinical care.

Objective

To determine the association between commonly assessed risk factors and poststroke detection of new AF in the STROKE AF cohort monitored by ICM.

Design, Setting, and Participants

This was a prespecified analysis of a randomized (1:1) clinical trial that enrolled patients between April 1, 2016, and July 12, 2019, with primary follow-up through 2020 and mean (SD) duration of 11.0 (3.0) months. Eligible patients were selected from 33 clinical research sites in the US. Patients had an index stroke attributed to large- or small-vessel disease and were 60 years or older or aged 50 to 59 years with at least 1 additional stroke risk factor. A total of 496 patients were enrolled, and 492 were randomly assigned to study groups (3 did not meet inclusion criteria, and 1 withdrew consent). Patients in the ICM group had the index stroke within 10 days before insertion. Data were analyzed from October 8, 2021, to January 28, 2022.

Interventions

ICM monitoring vs site-specific usual care (short-duration external cardiac monitoring).

Main Outcomes and Measures

The ICM device automatically detects AF episodes 2 or more minutes in length; episodes were adjudicated by an expert committee. Cox regression multivariable modeling included all parameters identified in the univariate analysis having P values <.10. AF detection rates were calculated using Kaplan-Meier survival estimates.

Results

The analysis included the 242 participants randomly assigned to the ICM group in the STROKE AF study. Among 242 patients monitored with ICM, 27 developed AF (mean [SD] age, 66.6 [9.3] years; 144 men [60.0%]; 96 [40.0%] women). Two patients had missing baseline data and exited the study early. Univariate predictors of AF detection included age (per 1-year increments: hazard ratio [HR], 1.05; 95% CI, 1.01-1.09; P = .02), CHA2DS2-VASc score (per point: HR, 1.54; 95% CI, 1.15-2.06; P = .004), chronic obstructive pulmonary disease (HR, 2.49; 95% CI, 0.86-7.20; P = .09), congestive heart failure (CHF; with preserved or reduced ejection fraction: HR, 6.64; 95% CI, 2.29-19.24; P < .001), left atrial enlargement (LAE; HR, 3.63; 95% CI, 1.55-8.47; P = .003), QRS duration (HR, 1.02; 95% CI, 1.00-1.04; P = .04), and kidney dysfunction (HR, 3.58; 95% CI, 1.35-9.46; P = .01). In multivariable modeling (n = 197), only CHF (HR, 5.06; 95% CI, 1.45-17.64; P = .05) and LAE (HR, 3.32; 1.34-8.19; P = .009) remained significant predictors of AF. At 12 months, patients with CHF and/or LAE (40 of 142 patients) had an AF detection rate of 23.4% vs 5.0% for patients with neither (HR, 5.1; 95% CI, 2.0-12.8; P < .001).

Conclusions and Relevance

Among patients with ischemic stroke attributed to large- or small-vessel disease, CHF and LAE were associated with a significantly increased risk of poststroke AF detection. These patients may benefit most from the use of ICMs as part of a secondary stroke prevention strategy. However, the study was not powered for clinical predictors of AF, and therefore, other clinical characteristics may not have reached statistical significance.

Trial Registration

ClinicalTrials.gov Identifier: NCT02700945.

Risk Assessment of the Door-In-Door-Out Process at Primary Stroke Centers for Patients With Acute Stroke Requiring Transfer to Comprehensive Stroke Centers

Background Patients with acute stroke at non- or primary stroke centers (PSCs) are transferred to comprehensive stroke centers for advanced treatments that reduce disability but experience significant delays in treatment and increased adjusted mortality. This study reports the results of a proactive, systematic, risk assessment of the door-in-door-out process and its application to solution design. Methods and Results A learning collaborative (clinicians, patients, and caregivers) at 2 PSCs and 3 comprehensive stroke centers in Chicago, Illinois participated in a failure modes, effects, and criticality analysis to identify steps in the process; failures of each step, underlying causes; and to characterize each failure's frequency, impact, and safeguards using standardized scores to calculate risk priority and criticality numbers for ranking. Targets for solution design were selected among the highest-ranked failures. The failure modes, effects, and criticality analysis process map and risk table were completed during in-person and virtual sessions. Failure to detect severe stroke/large-vessel occlusion on arrival at the PSC is the highest-ranked failure and can lead to a 45-minute door-in-door-out delay caused by failure to obtain a head computed tomography and computed tomography angiogram together. Lower risk failures include communication problems and delays within the PSC team and across the PSC comprehensive stroke center and paramedic teams. Seven solution prototypes were iteratively designed and address 4 of the 10 highest-ranked failures. Conclusions The failure modes, effects, and criticality analysis identified and characterized previously unrecognized failures of the door-in-door-out process. Use of a risk-informed approach for solution design is novel for stroke and should mitigate or eliminate the failures.

Prehospital Comprehensive Stroke Center vs Primary Stroke Center Triage in Patients With Suspected Large Vessel Occlusion Stroke

Importance

Endovascular therapy (EVT) improves functional outcomes in acute ischemic stroke (AIS) with large vessel occlusion (LVO). Whether implementation of a regional prehospital transport policy for comprehensive stroke center triage increases use of EVT is uncertain.

Objective

To evaluate the association of a regional prehospital transport policy that directly triages patients with suspected LVO stroke to the nearest comprehensive stroke center with rates of EVT.

Design, Setting, and Participants

This retrospective, multicenter preimplementation-postimplementation study used an interrupted time series analysis to compare treatment rates before and after implementation in patients with AIS arriving at 15 primary stroke centers and 8 comprehensive stroke centers in Chicago, Illinois, via emergency medical services (EMS) transport from December 1, 2017, to May 31, 2019 (9 months before and after implementation in September 2018). Data were analyzed from December 1, 2017, to May 31, 2019.

Interventions

Prehospital EMS transport policy to triage patients with suspected LVO stroke, using a 3-item stroke scale, to comprehensive stroke centers.

Main Outcomes and Measures

Rates of EVT before and after implementation among EMS-transported patients within 6 hours of AIS onset.

Results

Among 7709 patients with stroke, 663 (mean [SD] age, 68.5 [14.9] years; 342 women [51.6%] and 321 men [48.4%]; and 348 Black individuals [52.5%]) with AIS arrived within 6 hours of stroke onset by EMS transport: 310 of 2603 (11.9%) in the preimplementation period and 353 of 2637 (13.4%) in the postimplementation period. The EVT rate increased overall among all patients with AIS (preimplementation, 4.9% [95% CI, 4.1%-5.8%]; postimplementation, 7.4% [95% CI, 7.5%-8.5%]; P < .001) and among EMS-transported patients with AIS within 6 hours of onset (preimplementation, 4.8% [95% CI, 3.0%-7.8%]; postimplementation, 13.6% [95% CI, 10.4%-17.6%]; P < .001). On interrupted time series analysis among EMS-transported patients, the level change within 1 month of implementation was 7.15% (P = .04) with no slope change before (0.16%; P = .71) or after (0.08%; P = .89), which indicates a step rather than gradual change. No change in time to thrombolysis or rate of thrombolysis was observed (step change, 1.42%; P = .82). There were no differences in EVT rates in patients not arriving by EMS in the 6- to 24-hour window or by interhospital transfer or walk-in, irrespective of time window.

Conclusions and Relevance

Implementation of a prehospital transport policy for comprehensive stroke center triage in Chicago was associated with a significant, rapid, and sustained increase in EVT rate for patients with AIS without deleterious associations with thrombolysis rates or times.

Concordance between epidemiological evaluation of probability of transmission and whole genome sequence relatedness among hospitalized patients acquiring Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae

OBJECTIVES

We aimed to evaluate the concordance between epidemiologically determined transmission and genetic linkage of Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae (KPC-Kp).

METHODS

We included consecutive KPC-Kp carriers between December 2016 and April 2017 in a hospital endemic for KPC-Kp. We assessed epidemiological relatedness between patients by prospective investigations by the infection control team. The probability of epidemiological relatedness was classified into four groups: no suspected transmission, low, moderate and high probability of transmission. Whole-genome sequencing of isolates was performed. Genetic linkage between KPC-Kp isolates was expressed by distance between isolates in single nucleotide polymorphisms (SNPs). We established an SNP cut-off defining a different strain based on the reconstructed phylogenetic tree. We compared the epidemiological and genetic linkage of all isolates from all patients.

RESULTS

The study included 25 KPC-Kp carriers with 49 isolates. SNP variance was available for 1129 crossed patient-isolate pairs. Genomic linkage, based on a cut-off of 80 SNPs to define related isolates, was found in 115/708 (16.2%) of isolates with no transmission suspected epidemiologically, 27/319 (8.5%) of low, 11/26 (42.3%) of moderate and 64/76 (84.2%) of high epidemiological transmission risk determination (p < 0.001 for trend). Similar results and significant trends were shown on sensitivity analyses using a lower SNP cut-off (six SNPs) and patient-isolate unique pairs, analysing the first isolate from each patient.

CONCLUSIONS

While significant concordance between epidemiological and genomic transmission patterns was found, epidemiological investigations of transmission are limited by the possibility of unidentified transmissions or over-estimation of associations. Genetic linkage analysis is an important aid to epidemiological transmission assessment.

Risk of stroke after emergency department visits for neurologic complaints

Objective

To assess the risk of subsequent stroke among older patients discharged from an emergency department (ED) without a diagnosis of TIA or stroke.

Methods

Using electronic health record data from a large urban, university hospital and a community-based hospital, we analyzed patients aged 60-89 years discharged to home from the ED without an International Statistical Classification of Diseases and Related Health Problems, 9th or 10th Revision diagnosis of TIA or stroke. Based on the presence/absence of a head CT and the presence/absence of a chief complaint suggestive of TIA or stroke ("symptoms") during the index ED visit, we created 4 mutually exclusive groups (group 1, reference: head CT no, symptoms no; group 2: head CT no, symptoms yes; group 3: head CT yes, symptoms no; and group 4: head CT yes, symptoms yes). We calculated rates of stroke in the 30, 90, and 365 days after the index visit and used multivariable logistic regression to estimate odds ratios (ORs) for subsequent stroke.

Results

Among 35,622 patients (mean age 70 years, 59% women, and 16% African American), unadjusted rates of stroke in 365 days were as follows: group 4: 2.5%; group 3: 1.1%; group 2: 0.69%; and group 1: 0.54%. The adjusted OR for stroke was 3.30 (95% confidence interval [CI], 1.61-6.76) in group 4, 1.56 (95% CI, 1.16-2.09) in group 3, and 0.61 (95% CI, 0.22-1.67) in group 2.

Conclusions

Among patients discharged from the ED without a diagnosis of TIA or stroke, the occurrence of a head CT and/or specific neurologic symptoms established a clinically meaningful risk gradient for subsequent stroke.

Abstract WP284: Modelling Hospital-Level Costs of Thrombolysis to Strokes and Stroke Mimics

Introduction: When the diagnosis of stroke is not completely certain, the benefits of rapid treatment with tPA are widely thought to outweigh the minimal risk of complication associated with thrombolysis of stroke mimics (SM). However, acceptable rates of hospital-level SM treatment have not been well established.

Hypothesis: A cost-reimbursement (CR) analysis will identify a threshold of SM treatment with tPA above which the CR ratio is unacceptably high.

Methods: We used stochastic modeling with probability distributions to mathematically examine various tPA treatment scenarios. The main hospital-level variables used were: (1) case-mix or rate of SM and (2) percent of all eligible cases treated with tPA. For each case, a hospital cost was assigned based on whether or not tPA was given, onset to treatment time (OTT), length of stay based on severity distribution and expected clinical outcome, and whether the case was a true stroke or SM. The costs associated with index hospitalization, treatment complications, and non-treatment of true stroke patients were estimated from published rates and data. Reimbursement for stroke with and without thrombolysis as well as treated SM were estimated from Medicare rates. We calculated a CR ratio and identified thresholds of hospital SM treatment rates above which CR ratios are >1.0 and >1.5.

Results: Assuming that 75% of true eligible stroke patients are treated with tPA with median OTT of 120 minutes, we found an increase in CR ratio from 0.97 (0% SM rate) to 1.61 (100% SM rate). The SM rate of <10% was associated with CR of <1; the SM rate of >10% was associated with CR ratio >1.0 while SM rate >80% was required for a CR ratio >1.5. For each OTT interval (0-90 minutes, 90-180 minutes, 180-270 minutes), the CR ratio was on average 0.1 lower for a hospital with a 5% SM rate compared to a hospital with a 20% SM rate.

Conclusions: In a simulation study, we found the CR ratio increased with increasing OTT and hospital SM treatment rate. As other researchers have suggested, hospitals may need to carefully monitor rates of SM patients treated with tPA and establish performance metrics to lower costs and reduce patient harm.

Abstract 193: The 2CAN Score: A Novel Inpatient Stroke Recognition Instrument

Introduction: A quarter of strokes occur in patients hospitalized for another reason. Inpatient stroke alerts are challenging due to complex medical situations. A stroke recognition instrument may be useful for general practitioners to discern neurologic deficits due to hemorrhagic or ischemic stroke from mimics such as seizures, delirium, and hypoglycemia.

Hypothesis: Clinical factors present at the initial evaluation of suspected inpatient stroke patients will distinguish strokes from mimics.

Methods: This was a retrospective review of inpatient stroke alerts from 9/1/2014 to 7/31/2016. Final diagnosis of stroke was based on stroke attending documentation and imaging confirmation if available. We evaluated predictors of stroke diagnosis including demographics, stroke risk factors, stroke alert reason, post-operative status and time from admission, NIHSS and CPSS scores abstracted from notes, vital signs, and laboratory values. Using the first 165 patients for derivation and the second 165 for validation, we used univariate and multivariate logistic regression and c-statistics to derive and validate a scoring system to predict stroke diagnosis.

Results: Among 394 alerts, 64 were excluded due to incomplete documentation. Of 330 remaining patients, 116 (35.2%) were diagnosed with stroke, 43 (13.0%) had a neurological mimic (e.g., seizure), and 171 (51.8%) had a non-neurologic mimic (e.g., sepsis, drug effect, or delirium). In multivariate analysis in the derivation cohort, we identified 4 independent predictors of inpatient stroke: abnormal CPSS, post- C ardiac procedure, history of A trial fibrillation, and being a N ew (admitted within 24 hours) patient. The 2CAN score gives one point for each positive variable above, with additional 2 points for a CPSS ≥2 for a total score range from 0 to 6. The 2CAN score had c-statistic 0.93 (95% CI 0.88-0.97) in the derivation and 0.88 (95% CI 0.82-0.94) in the validation cohorts, respectively. A 2CAN score ≥2 had 92.2% sensitivity, 69.6% specificity, 62.2% positive predictive value, and 94.3% negative predictive value for identifying stroke.

Conclusion: The 2CAN score is a sensitive screening tool for identifying inpatient stroke. Further external and prospective validation of this score is warranted.

Abstract TP306: Risk of Stroke After ED Visits at Which No Diagnosis of TIA or Stroke was Recorded

Introduction: Unrecognized, high-risk conditions like transient ischemic attack (TIA) are missed opportunities to initiate timely preventive treatment to reduce the risk of subsequent stroke, disability, and death. Up to 50% of patients with a TIA may have a subsequent disabling stroke, many within 30 days.

Hypothesis: Among patients with an Emergency Department (ED) visit at which no diagnosis of TIA or stroke was recorded, analysis of electronic health record (EHR) data can help predict risk of subsequent stroke.

Methods: We performed a retrospective cohort study of EHR data (2011-2015) from a high-volume comprehensive stroke center with an annual ED volume of >85,000. Patients age 60-89 years who were discharged to home from the ED in <24 hours without ICD-9 diagnosis of TIA or stroke were included for analysis. If patients had >1 qualifying index visit during the study period, we used the first. For each patient we determined presence or absence during the ED visit of a head CT and/or any of these strings in the ED chief complaint (“Symptoms”): slur, speech, aphasia, confuse, word, difficult, comprehen, weak, clumsy, clumsiness, droop, paralysis, move, moving, face, or facial (but not “facial injury”). In four mutually-exclusive categories, CT (Yes/No) by Symptoms (Yes/No), we calculated rate of stroke in the 30, 90, and 365-day periods after discharge from the ED. Ischemic stroke ascertainment was based on diagnostic codes at subsequent ED or hospital visits.

Results: Among 40,450 patients, mean age was 69 years, and 59% were women. Race was 57% white, 15% African-American, 23% other, and 4% unknown. Numbers of patients and rates of stroke by category are shown in the table.

Conclusion: This simple approach established a clinically meaningful risk gradient across four groups. Present and future work to refine this model may contribute to comparative effectiveness research that evaluates management and triage strategies for patients across the stroke risk spectrum.

Superior survival of breast cancer BRCA1 /2 mutation carriers harboringG/G at the -309 position at the MDM2 promoter compared to those harboring T/T or G/T at this SNP

10600

Background: A germ line single polymorphism in the promoter of the gene encoding the important modulator of P53, MDM2 has been described. The findings of G/G nucleotides at this position in contrast to G/Tor T/T were demonstrated to increase MDM2 transcriptional levels and were correlated with younger onset of cancers in patients with the Li-Fraumeni syndrome. Furhtermore gastric cancer patients harboring T/T at this position and treated with chemotherapy were found to have decresed survival compared to the other SNP carriers. P53 mutations appear in high frequency in tumors associated with BRCA1/2 mutations. Indeed it has been suggested that mutations in the p53 gene are a necessary step in tumorigenesis in BRCA tumors. Methods: Here we investigate the effect of the MDM2 SNP309 on overall survival and age of onset in breast cancer patients. MDM2 SNP309 was evaluated in Breast cancer Ashkenazy patients analyzed for the three common mutations in BRCA1/2- 180 patients who are positive for either of these mutation and 272 negative ones. 194 negative, Disease onset age and survival were analyzed for the different subgroups Results: Around a quarter of the whole population analyzed were identified as carriers of G/G at the -309 MDM2. There was no correlation between age of disease onset in either BRCA1/2mutation carriers and the specific genotype. In the BRCA1/2 mutation carriers we found a survival advantage in patients harboring the SNP309 G/G genotype(p-0.001 log rank test). Such an effect was not demonstrated in patients tested negative for the known Ashkenazy mutations Conclusions: In specific subgroups of breast cancer patients SNP309 G/G is associated with improved patient survival. A possible explanation for this finding could be the presence of a P53 which can be reactivated in the MDM2 SNP309 G/G carriers.

No significant financial relationships to disclose.

Diet restriction in mice causes a decrease in hippocampal choline uptake and muscarinic receptors that is restored by administration of tyrosine: interaction between cholinergic and adrenergic receptors influencing cognitive function

We have studied the effects of diet restriction (DR) to 60% and 40% of daily requirements, and tyrosine administration on cognitive function in mice, to define the nutritional-neurochemical interactions on autonomic tone involved in behavior and energy regulation. Cognitive function in the Morris Water maze was significantly impaired after 40% DR compared to both control and 60% DR. It was restored after tyrosine in association with increased M1 cholinergic and beta-adrenergic receptor function, and decreased alpha-adrenergic function. DR to 40% significantly decreased choline uptake (p <.05) and M1 receptor number (Bmax) (p <.05), without changes in affinity (Kd), choline acetyl transferase (ChAT) or acetyl cholinesterase (AChE) activity. Tyrosine administration significantly increased choline uptake (Bmax) (p <.05) and M1 density in the 40% DR (p <.01) without changes in affinity. ChAT activity was decreased after tyrosine--significantly after 40% DR (p <.05) while AChE was not affected. Both M1 mRNA and protein were not influenced by DR or tyrosine administration. Tyrosine hydroxylase mRNA was decreased significantly by 40% DR (p <.01). The effect of DR and tyrosine appeared to be both pre- and post-synaptic, indicating modulation of cholinergic activity by adrenergic tone. Nutritional effect on behavior and autonomic tone may have implications for the treatment of mood changes associated with weight loss and semi-starvation.

Tyrosine improves appetite, cognition, and exercise tolerance in activity anorexia

PURPOSE

We have modified for mice the activity wheel model of Routtenberg to study the effects of tyrosine on exercise tolerance, behavior, and brain neurochemistry.

METHODS

Mice were fed for 2 h.d(-1) over a 2-wk period. During the second week, each group was injected daily with either saline or tyrosine (100 mg.kg(-1).d(-1)) and exercised on a running wheel. Controls were in cages with inactivated wheels and received the same treatment and feeding protocols as the experimental groups. Food consumption and cognitive function (eight-arm maze) were evaluated for 1 wk. Brains were then assayed for adrenergic and serotonergic metabolites.

RESULTS

Activity together with a restricted diet caused extreme weight loss (27%) (P < 0.001) together with decreased food consumption (22%) (P < 0.001). Tyrosine restored food consumption to that of the controls (P < 0.001) with no effect on weight, since there was a 22% increase in activity (P < 0.001). Saline injections caused an 18% decrease in activity (P < 0.001). Both activity and tyrosine improved maze performance (P < 0.05). In the hypothalamus, activity caused a significant increase in 5-hydroxytryptamine (5-HT) (P < 0.001), 5-hydroxyindoleacetic acid (5-HIAA) (P < 0.01), and dopamine (P < 0.05); tyrosine prevented the increase in 5-HT (P < 0.05) and increased 5-HIAA in the controls (P < 0.01). With regard to hippocampal 5-HT, there was a significant increase in 5-HIAA following activity (P < 0.05), whereas tyrosine caused significant increase in 5-HIAA in the controls (P < 0.01). Activity significantly decreased the level of hippocampal 3,4-dihydroxyphenylacetic acid (DOPAC), whereas tyrosine decreased its level only in the controls (both at P < 0.0001). The level of tyrosine hydroxylase increased with activity (P < 0.05), and tyrosine decreased it significantly (P < 0.05).

CONCLUSION

Activity anorexia is associated with increased hypothalamic 5-HT concentrations. Tyrosine administration reverses this, and significantly improves food consumption, cognitive behavior, and activity performance. Such nutritional modulations may have implications for the treatment of eating disorders and, in normal circumstances, tyrosine may improve exercise tolerance and delay fatigue.

Recurrence methods in the analysis of learning processes

The goal of most learning processes is to bring a machine into a set of "correct" states. In practice, however, it may be difficult to show that the process enters this target set. We present a condition that ensures that the process visits the target set infinitely often almost surely. This condition is easy to verify and is true for many well-known learning rules. To demonstrate the utility of this method, we apply it to four types of learning processes: the perceptron, learning rules governed by continuous energy functions, the Kohonen rule, and the committee machine.

A new on-line learning model

We introduce a new supervised learning model that is a nonhomogeneous Markov process and investigate its properties. We are interested in conditions that ensure that the process converges to a "correct state," which means that the system agrees with the teacher on every "question." We prove a sufficient condition for almost sure convergence to a correct state and give several applications to the convergence theorem. In particular, we prove several convergence results for well-known learning rules in neural networks.

Heart rate variability as a marker of myocardial perfusion

RR variability (HRV), an independent predictor of death following myocardial infarction, may also be related to other features of coronary artery disease. We evaluated its ability to differentiate among sedentary patients with chest pain >/=45 years of age demonstrating either normal or abnormal myocardial perfusion with rest and exercise thallium-210 tomographic imaging. The major HRV difference between 48 men and 50 women with normal perfusion was a significantly higher high frequency power in women. No significant differences in mean HRV values were found between the 57 men with abnormal perfusion scans and the 48 men with normal perfusion. In both men and women with normal perfusion scans, duration of exercise was significantly related to age. In men with abnormal scans, impaired myocardial perfusion alters the relationship between exercise duration and age, and a group of individuals with diminished HRV and low levels of physical fitness, regardless of age, can be identified. Despite these latter selective findings, we conclude that HRV is not a sensitive indicator to differentiate patients with normal and abnormal myocardial perfusion.

Do high impact exercises produce higher tibial strains than running?

BACKGROUND

Bone must have sufficient strength to withstand both instantaneous forces and lower repetitive forces. Repetitive loading, especially when bone strain and/or strain rates are high, can create microdamage and result in stress fracture

AIM

To measure in vivo strains and strain rates in human tibia during high impact and moderate impact exercises.

METHODS

Three strain gauged bone staples were mounted percutaneously in a rosette pattern in the mid diaphysis of the medial tibia in six normal subjects, and in vivo tibial strains were measured during running at 17 km/h and drop jumping from heights of 26, 39, and 52 cm.

RESULTS

Complete data for all three drop jumps were obtained for four of the six subjects. No statistically significant differences were found in compression, tension, or shear strains with increasing drop jump height, but, at the 52 cm height, shear strain rate was reduced by one third (p = 0.03). No relation was found between peak compression strain and calculated drop jump energy, indicating that subjects were able to dissipate part of the potential energy of successively higher drop jumps by increasing the range of motion of their knee and ankle joints and not transmitting the energy to their tibia. No statistically significant differences were found between the principal strains during running and drop jumping from 52 cm, but compression (p = 0.01) and tension (p = 0.004) strain rates were significantly higher during running.

CONCLUSIONS

High impact exercises, as represented by drop jumping in this experiment, do not cause higher tibial strains and strain rates than running and therefore are unlikely to place an athlete who is accustomed to fast running at higher risk for bone fatigue.

In-vivo strain measurements to evaluate the strengthening potential of exercises on the tibial bone

Mechanical loading during physical activity produces strains within bones. It is thought that these forces provide the stimulus for the adaptation of bone. Tibial strains and rates of strain were measured in vivo in six subjects during running, stationary bicycling, leg presses and stepping and were compared with those of walking, an activity which has been found to have only a minimal effect on bone mass. Running had a statistically significant higher principal tension, compression and shear strain and strain rates than walking. Stationary bicycling had significantly lower tension and shear strains than walking. If bone strains and/or strain rates higher than walking are needed for tibial bone strengthening, then running is an effective strengthening exercise for tibial bone.

In vivo strain measurements to evaluate the strengthening potential of exercises on the tibial bone

Mechanical loading during physical activity produces strains within bones. It is thought that these forces provide the stimulus for the adaptation of bone. Tibial strains and rates of strain were measured in vivo in six subjects during running, stationary bicycling, leg presses and stepping and were compared with those of walking, an activity which has been found to have only a minimal effect on bone mass.

Running had a statistically significant higher principal tension, compression and shear strain and strain rates than walking. Stationary bicycling had significantly lower tension and shear strains than walking. If bone strains and/or strain rates higher than walking are needed for tibial bone strengthening, then running is an effective strengthening exercise for tibial bone.

Effect of microwave oven induced mild hyperthermia on bone viability and strength

Extracorporeal hyperthermia treatment of bone followed by reimplantation may be an option for treating bone tumors. However, intensive heat treatment, such as autoclaving, causes a decline of mechanical and biologic functions of bone tissue. In the current study, a microwave oven was used for minimal hyperthermic treatment, and it was found that complete eradication of all viable cells in rat bone could be achieved with minimal reduction in mechanical function. When the cells were evaluated histologically by special lactate dehydrogenase activity staining, complete bone cell death occurred after 60 seconds of heating in an empty Petri dish and after 30 seconds when heated in a Petri dish containing normal saline. Mechanical stiffness and strength of the bones, tested in three-point bending, showed no decrease after this heating. Microwave oven induced hyperthermia eradication of viable cells without significant damage to the mechanical properties may have clinical relevance in limb salvage tumor surgery.

Prevention of stress fractures using custom biomechanical shoe orthoses

In a prospective study of stress fractures the hypothesis that training with custom made biomechanical shoe orthoses could lessen the incidence of stress fractures in infantry recruits was tested. Recruits were assigned randomly to groups and given soft biomechanical orthoses or semirigid biomechanical orthoses and compared with a control group that did not train in biomechanical orthoses. All recruits wore infantry boots with soles designed like those of basketball shoes. Recruits were examined biweekly during 14 weeks of basic training. The incidence of stress fractures was 15.7% for the recruits with the semirigid biomechanical orthoses, 10.7% for the recruits with the soft biomechanical orthoses, and 27% for the control group. The soft biomechanical orthoses were tolerated better by the recruits than were the semirigid devices. Among trainees at high risk for stress fractures, prophylactic use of custom made biomechanical orthoses may be warranted.

Effect of cane use on tibial strain and strain rates

The effect of cane ambulation on hip biomechanics has been well studied, but its effect on tibial strains and strain rates is not known. To test the hypothesis that cane use may lower tibial strain and strain rates during walking, percutaneous axial extensometers were mounted on the right medial cortex of the midtibial diaphysis in seven male volunteers. In vivo peak-to-peak axial tibial strains and strain rates were measured for ipsilateral and contralateral cane usage and compared with a no cane control. Cane-assisted ambulation was not found to significantly lower strain magnitudes; however, tibial strain rates were significantly lowered by both ipsilateral and contralateral cane usage. We conclude that either ipsilateral or contralateral cane usage may be beneficial when lowering tibial strain rate is desired, such as in the treatment of tibia stress fracture or osteoarthrosis of the knee.

Effect of moderate bone hyperthermia on cell viability and mechanical function

Extracorporeal hyperthermia treatment of bone followed by its reimplantation may be an optional treatment of bone tumors. In this study, the authors examined the minimal hyperthermic condition in which complete eradication of all viable cells in rat bone can be achieved and the mechanical effect of this treatment on the tested bone. When the results were evaluated histologically by special lactate dehydrogenase activity staining, it was found that complete bone cell death occurred after 30 minutes of heating at 60 degrees C. Cartilage cells, including those of the epiphysis, were more resistant to thermal damage. When the ability of the specimens to proliferate in cell cultures was tested, no growth was observed after heating at temperatures of 50 degrees C or greater. The mechanical stiffness tested in the Instron machine showed decreased bone stiffness at 70 degrees C but no change in the breaking load of the bones. Controlled hyperthermia's ability to eradicate viable cells without significant damage to the mechanical properties may have clinical relevance in limb salvage tumor surgery.

A comparison of the effect of shoes on human tibial axial strains recorded during dynamic loading

Percutaneous axial extensometers were mounted on the medial cortex of the midtibial diaphysis in seven male volunteers and the effect of three different shoes on in vivo peak-to-peak axial compression-tension strains measured during dynamic loading. Zohar shoes had lower axial strains and strain rates during treadmill walking than Nike Air Max running shoes or Israeli infantry boots. During running on a running track, there was no statistically significant difference between the axial strains or strain rates between the shoes tested. Shoe gear can modify tibial strains and strain rates that contribute to the development of tibial stress fractures.

Anatomic considerations of the foot and leg in tibial hemimelia

Five lower extremities from four patients with tibial hemimelia were available for dissection. Multiple tendon anomalies were present. The ankle articulation was found to have a nonfunctional uniplanar motion. Multiple coalitions of the osseous structures of the foot were found, with subtalar coalition the most common.

Multiple protein complexes, including AP2 and Sp1, interact with a specific site within the rat preprotachykinin-A promoter

We demonstrate that there is a unique AP2 binding site in the rat preprotachykinin-A promoter (rPPT) spanning -865 to -47. AP2 is a transcription factor whose expression in sensory neurons has been correlated with rPPT expression in these cells. This binding site is adjacent to an element we previously identified as binding a single stranded DNA binding protein which was also present in sensory neurons. These two complexes encompass a region which we had proposed might form a stem-loop structure, allowing binding of the single stranded DNA binding protein to the DNA. Here using electrophoretic mobility shift analysis we demonstrate that the DNA region corresponding to the putative stem-loop structure is bound by a variety of transcription factors, including in addition to AP2 the ubiquitous Sp1. DNase 1 footprint analysis demonstrates that binding to this domain by the proteins recognising the double-stranded form of the cis acting element is mutually exclusive. A promoter fragment containing this domain demonstrated a DNase 1 footprint over the 5' region of the stem-loop structure. Competition of the binding for this element by an oligonucleotide corresponding to the stem-loop structure removed the 5' footprint and exposed a new footprint over the 3' region of the stem-loop structure and extending for several base pairs. This change in protection observed with DNase 1 digestion also correlated with changes of the DNase 1 pattern at specific locations 3' of the proposed stem-loop structure. These changes correlated with two DNA sequences which were homologous to one another and to a region within the proposed stem-loop structure. Our results indicate that AP2 could regulate rPPT gene expression by a variety of mechanisms.

Stress and antidepressant effects on hippocampal and cortical 5-HT1A and 5-HT2 receptors and transport sites for serotonin

The interactions between 14 days of repeated restraint stress and daily administration of imipramine or tianeptine (2 h before the beginning of stress) were investigated in rats to assess responses of 5-HT2 and 5-HT1A receptors and serotonin transporter sites labelled by [3H]paroxetine in the cerebral cortex and hippocampus, two brain regions in which adrenal steroid effects on serotonin receptor-binding have been reported. 5-HT2 sites, labelled by [125I]7-amino-8-iodo ketanserin, were decreased in parietal cerebral cortex layers 3 and 5 by imipramine treatment, but not by tianeptine treatment and not by daily restraint stress. Stress, but not antidepressant, depressed 5-HT1A sites labelled with [3H]8-hydroxy-DPAT in hippocampal fields CA3, CA4 and dentate gyrus. [3H]paroxetine-binding to serotonin transporter sites was decreased by tianeptine treatment as well as by imipramine in both hippocampus and cerebral cortex, with some overlap of the fields that were significantly affected, whereas there were no effects of stress per se and no evidence of a stress x drug interaction. These results are discussed in relation to similarities and differences in the effects of different antidepressant drugs on the serotonergic system of the rat brain. Whereas the actions of imipramine and tianeptine on 5-HT2 and 5-HT1A receptors are specific to each drug, the surprising finding of a similar effect of both drugs to reduce serotonin transporter sites labelled by [3H]paroxetine suggest the possibility of a common action for these two drugs in spite of their opposite effects on serotonin re-uptake.

Intermale social aggression: suppression by medial preoptic area lesions

The intermale social aggressive behavior of male rats cohabiting with a female rat was quantitatively scored weekly in response to the introduction of an unfamiliar intruding male. Resident male rats whose aggressiveness toward an intruder reached a criterion level were subjected to either sham lesions or bilateral lesions in the region of the medial preoptic area. The lesioned rats continued to exhibit levels of piloerection and lateral attack that were not significantly lower than those of sham-lesioned animals. However, the lesioned animals did emit significantly fewer bites and spent significantly less time in the "on-top" position than did sham-lesioned animals. The lesioned animals also displayed significantly less sexual behavior than the sham-lesioned animals but were not different in terms of defensiveness toward the experimenter. It is suggested that bilateral lesions in the region of the medial preoptic area cause a decrease in the intensity of intermale social aggression but do not prevent external stimuli from eliciting the aggression.

Comparison of low-dose subcutaneous heparin calcium and heparin sodium on ecchymosis formation

Ecchymosis formation in patients receiving identical concentrations of heparin calcium or heparin sodium was compared in a double-blind study. Sixty-three patients admitted to a coronary-care unit with orders to receive heparin 5000 units subcutaneously every 12 hours were randomly assigned to receive either heparin calcium or heparin sodium. The drugs were administered identically. The presence and size of any ecchymosis were recorded by a single observer. The 44 patients on whom data were collected received 86 heparin sodium and 102 heparin calcium injections. While there were no difference between salts in the percentage of patients with documented ecchymosis , significantly more injection sites with ecchymosis were reported for the calcium salt. No significant difference was found in bruise size between the calcium and sodium salts of heparin. In a subgroup of patients who were not receiving other drugs known to prolong bleeding, there was no significant difference between the salts in the percentage of patients and injection sites with ecchymosis . The subcutaneous administration of heparin calcium resulted in significantly more injection sites with ecchymosis than did heparin sodium, but the size of the reported ecchymosis was not different between the two groups.

Increased blood-brain barrier permeability to tetracycline in rabbits under dysbaric conditions

Alteration of the blood-brain barrier (BBB) by dysbaric exposure may have relevance in several areas of hyperbaric medicine. Drugs administered to persons exposed to dysbaric conditions, e.g., divers, compressed air workers, may penetrate the brain in amounts that could produce toxic or undesirable effects. Modification of the BBB may also have pathogenetic implications in decompression sickness. Furthermore, increased BBB permeability to certain potentially useful antitumor agents, antibiotics, and other compounds under dysbaric conditions may provide the basis for a new therapeutic approach. This report concerns the influence of dysbaric exposure on BBB permeability to an antibiotic. Tetracycline (5-40 mg/kg) was intravenously injected in 22 experimental rabbits (subjected to air compression-decompression) and 17 controls (kept at ambient pressure). Fluorescence microscopy and spectrometry revealed significantly greater tetracycline concentrations in 72.7% of the experimental brains. With the 5 mg/kg dose, the mean tetracycline concentrations was 0.17 micrograms/g in control brains and 0.33 micrograms/g in experimentals. These results indicate that dysbaric exposure increases BBB permeability to tetracycline. It appears that BBB alteration is related to intravascular gas bubbles but is independent of the development of decompression sickness. The conclusions of this investigation are pertinent to brain pharmacotherapy and may provide some new insight into the mechanism of decompression sickness. They also point to potential risks connected with drug administration under dysbaric conditions that can alter BBB permeability.