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Dive into the research topics where May Kim-Tenser is active.

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Featured researches published by May Kim-Tenser.


The New England Journal of Medicine | 2018

Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging

Gregory W. Albers; Michael P. Marks; Stephanie Kemp; Soren Christensen; Jenny P. Tsai; Santiago Ortega-Gutierrez; Ryan A McTaggart; Michel T. Torbey; May Kim-Tenser; Thabele M Leslie-Mazwi; Amrou Sarraj; Scott E. Kasner; Sameer A. Ansari; Sharon D. Yeatts; Scott Hamilton; Michael Mlynash; Jeremy J. Heit; Greg Zaharchuk; Sun Kim; Janice Carrozzella; Yuko Y. Palesch; Andrew M. Demchuk; Roland Bammer; Philip W. Lavori; Joseph P. Broderick; Maarten G. Lansberg

Background Thrombectomy is currently recommended for eligible patients with stroke who are treated within 6 hours after the onset of symptoms. Methods We conducted a multicenter, randomized, open‐label trial, with blinded outcome assessment, of thrombectomy in patients 6 to 16 hours after they were last known to be well and who had remaining ischemic brain tissue that was not yet infarcted. Patients with proximal middle‐cerebral‐artery or internal‐carotid‐artery occlusion, an initial infarct size of less than 70 ml, and a ratio of the volume of ischemic tissue on perfusion imaging to infarct volume of 1.8 or more were randomly assigned to endovascular therapy (thrombectomy) plus standard medical therapy (endovascular‐therapy group) or standard medical therapy alone (medical‐therapy group). The primary outcome was the ordinal score on the modified Rankin scale (range, 0 to 6, with higher scores indicating greater disability) at day 90. Results The trial was conducted at 38 U.S. centers and terminated early for efficacy after 182 patients had undergone randomization (92 to the endovascular‐therapy group and 90 to the medical‐therapy group). Endovascular therapy plus medical therapy, as compared with medical therapy alone, was associated with a favorable shift in the distribution of functional outcomes on the modified Rankin scale at 90 days (odds ratio, 2.77; P<0.001) and a higher percentage of patients who were functionally independent, defined as a score on the modified Rankin scale of 0 to 2 (45% vs. 17%, P<0.001). The 90‐day mortality rate was 14% in the endovascular‐therapy group and 26% in the medical‐therapy group (P=0.05), and there was no significant between‐group difference in the frequency of symptomatic intracranial hemorrhage (7% and 4%, respectively; P=0.75) or of serious adverse events (43% and 53%, respectively; P=0.18). Conclusions Endovascular thrombectomy for ischemic stroke 6 to 16 hours after a patient was last known to be well plus standard medical therapy resulted in better functional outcomes than standard medical therapy alone among patients with proximal middle‐cerebral‐artery or internal‐carotid‐artery occlusion and a region of tissue that was ischemic but not yet infarcted. (Funded by the National Institute of Neurological Disorders and Stroke; DEFUSE 3 ClinicalTrials.gov number, NCT02586415.)


BMJ | 2015

Incidence of "never events" among weekend admissions versus weekday admissions to US hospitals: national analysis.

Frank J. Attenello; Timothy Wen; Steven Cen; Alvin Ng; May Kim-Tenser; Nerses Sanossian; Arun Paul Amar; William J. Mack

Objective To evaluate the association between weekend admission to hospital and 11 hospital acquired conditions recently considered by the Centers for Medicare and Medicaid as “never events” for which resulting healthcare costs are not reimbursed. Design National analysis. Setting US Nationwide Inpatient Sample discharge database. Participants 351 million patients discharged from US hospitals, 2002-10. Main outcome measures Univariate rates and multivariable likelihood of hospital acquired conditions among patients admitted on weekdays versus weekends, as well as the impacts of these events on prolonged length of stay and total inpatient charges. Results From 2002 to 2010, 351 170 803 patients were admitted to hospital, with 19% admitted on a weekend. Hospital acquired conditions occurred at an overall frequency of 4.1% (5.7% among weekend admissions versus 3.7% among weekday admissions). Adjusting for patient and hospital cofactors the probability of having one or more hospital acquired conditions was more than 20% higher in weekend admissions compared with weekday admissions (odds ratio 1.25, 95% confidence interval 1.24 to 1.26, P<0.01). Hospital acquired conditions have a negative impact on both hospital charges and length of stay. At least one hospital acquired condition was associated with an 83% (1.83, 1.77 to 1.90, P<0.01) likelihood of increased charges and 38% likelihood of prolonged length of stay (1.38, 1.36 to 1.41, P<0.01). Conclusion Weekend admission to hospital is associated with an increased likelihood of hospital acquired condition, cost, and length of stay. Future protocols and staffing regulations must be tailored to the requirements of this high risk subgroup.


Journal of the American Heart Association | 2016

Trends in Acute Ischemic Stroke Hospitalizations in the United States

Lucas Ramirez; May Kim-Tenser; Nerses Sanossian; Steven Cen; Ge Wen; Shuhan He; William J. Mack; Amytis Towfighi

Background Population‐based studies have revealed declining acute ischemic stroke (AIS) hospitalization rates in the United States, but no study has assessed recent temporal trends in race/ethnic‐, age‐, and sex‐specific AIS hospitalization rates. Methods and Results Temporal trends in hospitalization for AIS from 2000 to 2010 were assessed among adults ≥25 years using the Nationwide Inpatient Sample. Age‐, sex‐, and race/ethnic‐specific and age‐adjusted stroke hospitalization rates were calculated using the weighted number of hospitalizations and US census data. From 2000 to 2010, age‐adjusted stroke hospitalization rates decreased from 250 to 204 per 100 000 (overall rate reduction 18.4%). Age‐specific AIS hospitalization rates decreased for individuals aged 65 to 84 years (846 to 605 per 100 000) and ≥85 years (2077 to 1618 per 100 000), but increased for individuals aged 25 to 44 years (16 to 23 per 100 000) and 45 to 64 years (149 to 156 per 100 000). Blacks had the highest age‐adjusted yearly hospitalization rates, followed by Hispanics and whites (358, 170, and 155 per 100 000 in 2010). Age‐adjusted AIS hospitalization rates increased for blacks but decreased for Hispanics and whites. Age‐adjusted AIS hospitalization rates were lower in women and declined more steeply compared to men (272 to 212 per 100 000 in women versus 298 to 245 per 100 000 in men). Conclusions Although overall stroke hospitalizations declined in the United States, the reduction was more pronounced among older individuals, women, Hispanics, and whites. Renewed efforts at targeting risk factor control among vulnerable individuals may be warranted.


Neurosurgical Focus | 2011

Therapeutic hypothermia in acute ischemic stroke.

Leonid Groysman; Benjamin Emanuel; May Kim-Tenser; Gene Sung; William J. Mack

Induced hypothermia has been used for neuroprotection in cardiac and neurovascular procedures. Experimental and translational studies provide evidence for its utility in the treatment of ischemic cerebrovascular disease. Over the past decade, these principles have been applied to the clinical management of acute stroke. Varying induction methods, time windows, clinical indications, and adjuvant therapies have been studied. In this article the authors review the mechanisms and techniques for achieving therapeutic hypothermia in the setting of acute stroke, and they outline pertinent side effects and complications. The manuscript summarizes and examines the relevant clinical trials to date. Despite a reasonable amount of existing data, this review suggests that additional trials are warranted to define the optimal time window, temperature regimen, and precise clinical indications for induction of therapeutic hypothermia in the setting of acute stroke.


World Neurosurgery | 2014

Health Disparities in Time to Aneurysm Clipping/Coiling Among Aneurysmal Subarachnoid Hemorrhage Patients: A National Study

Frank J. Attenello; Kelsey Wang; Timothy Wen; Steven Cen; May Kim-Tenser; Arun Paul Amar; Nerses Sanossian; Steven L. Giannotta; William J. Mack

OBJECTIVE Previous studies have suggested disparities in quality of health care and time to treatment across socioeconomic groups. Such differences can be of greatest consequence in the setting of emergent medical conditions. Surgical or endovascular treatment of ruptured cerebral aneurysms within the first 3 days of aneurysmal subarachnoid hemorrhage (aSAH) is associated with improved outcome. We hypothesize that race and payer status disparities effect the time to treatment for ruptured aneurysms. METHODS Discharge data were collected from the Nationwide Inpatient Sample during the years 2002-2010. International Classification of Diseases, 9th Edition; Clinical Modification codes were used to identify patients with aSAH who were treated by either surgical clipping or endovascular coil embolization. Time to procedure was dichotomized into 1) treatment in 3 days or less or 2) treatment in greater than 3 days. Time to treatment was evaluated according to demographic factors, including race, payer status, and median zip code income via multivariable analysis. RESULTS A total of 78,070 aSAH admissions were treated by either aneurysm clip ligation or coil embolization. Hispanic race and Medicaid payer status were associated with increased time to treatment (P < 0.05). CONCLUSION Racial and socioeconomic factors are associated with delayed time to treatment in aSAH. Identification of factors underlying these delays and standardization of care may allow for more uniform treatment protocols and improved patient care.


Western Journal of Emergency Medicine | 2014

Expansion of U.S. Emergency Medical Service Routing for Stroke Care: 2000–2010

Natalie Hanks; Ge Wen; Shuhan He; Sarah Song; Jeffrey L. Saver; Steven Cen; May Kim-Tenser; William J. Mack; Nerses Sanossian

Introduction Organized stroke systems of care include preferential emergency medical services (EMS) routing to deliver suspected stroke patients to designated hospitals. To characterize the growth and implementation of EMS routing of stroke nationwide, we describe the proportion of stroke hospitalizations in the United States (U.S.) occurring within regions having adopted these protocols. Methods We collected data on ischemic stroke using International Classification of Diseases-9 (ICD-9) coding from the Healthcare Cost and Utilization Project Nationwide Inpatient Sample (NIS) database from the years 2000–2010. The NIS contains all discharge data from 1,051 hospitals located in 45 states, approximating a 20% stratified sample. We obtained data on EMS systems of care from a review of archives, reports, and interviews with state emergency medical services (EMS) officials. A county or state was considered to be in transition if the protocol was adopted in the calendar year, with establishment in the year following transition. Results Nationwide, stroke hospitalizations remained constant over the course of the study period: 583,000 in 2000 and 573,000 in 2010. From 2000–2003 there were no states or counties participating in the NIS with EMS systems of care. The proportion of U.S. stroke hospitalizations occurring in jurisdictions with established EMS regional systems of acute stroke care increased steadily from 2004 to 2010 (1%, 13%, 28%, 30%, 30%, 34%, 49%). In 2010, 278,538 stroke hospitalizations, 49% of all U.S. stroke hospitalizations, occurred in areas with established EMS routing, with an additional 18,979 (3%) patients in regions undergoing a transition to EMS routing. Conclusion In 2010, a majority of stroke patients in the U.S. were hospitalized in states with established or transitioning to organized stroke systems of care. This milestone coverage of half the U.S. population is a major advance in systematic stroke care and emphasizes the need for novel approaches to further extend access to stroke center care to all patients.


Journal of NeuroInterventional Surgery | 2016

Evaluation of time to aneurysm treatment following subarachnoid hemorrhage: comparison of patients treated with clipping versus coiling

Frank J. Attenello; Patrick Reid; Timothy Wen; Steven Cen; May Kim-Tenser; Nerses Sanossian; Jonathan J. Russin; Arun Paul Amar; Steven L. Giannotta; William J. Mack; Matthew S. Tenser

Introduction Prior studies of aneurysmal subarachnoid hemorrhage (SAH) have shown that treatment at teaching institutions and decreased time to surgery are factors that correlate with improved patient outcome. We aimed to individually evaluate the effect of teaching institution treatment on rates of surgical clipping or endovascular coiling. Methods Patients with SAH treated by either aneurysm clipping or coiling between 2002 and 2010 in the Nationwide Inpatient Sample were analyzed. Time to aneurysm treatment was dichotomized to >3 days or ≤3 days and evaluated by multivariable logistic regression modeling, controlling for patient and hospital covariates. Identified predictors for prolonged time to procedure were compared between the clipping and coiling populations. Results Between 2002 and 2010 there were 90 684 SAH admissions with subsequent clipping and coiling procedures. Treatment at teaching hospitals was associated with faster time to clipping (OR 0.60, 95% CI 0.44 to 0.80, p=0.001) but not coiling procedures (p=0.66). Likewise, older age (≥80 years) was associated with delays to clipping (p<0.05) but not coiling procedures (p>0.05). Patients with delayed time to treatment were associated with increased rates of moderate to severe neurological disability. Conclusions Older patients with SAH and those treated at non-teaching hospitals were more likely to have delays to aneurysm clipping procedures. These associations were unique to open surgery as age and hospital teaching status did not affect time to coiling procedures.


Stroke | 2015

Routing Ambulances to Designated Centers Increases Access to Stroke Center Care and Enrollment in Prehospital Research

Nerses Sanossian; David S. Liebeskind; Marc Eckstein; Sidney Starkman; Samuel J. Stratton; Franklin D Pratt; William Koenig; Scott Hamilton; May Kim-Tenser; Robin Conwit; Jeffrey L. Saver

Background and Purpose— Emergency medical services routing of patients with acute stroke to designated centers may increase the proportion of patients receiving care at facilities meeting national standards and augment recruitment for prehospital stroke research. Methods— We analyzed consecutive patients enrolled within 2 hours of symptom onset in a prehospital stroke trial, before and after regional Los Angeles County Emergency Medical Services implementation of preferentially routing patients with acute stroke to approved stroke centers (ASCs). From January 2005 to mid-November 2009, patients were transported to the nearest emergency department, whereas from mid-November 2009 to December 2012, patients were preferentially transported to first 9, and eventually 29, ASCs. Results— There were 863 subjects enrolled before and 764 after emergency medical service preferential routing, with implementation leading to an increase in the proportion cared for at an ASC from 10% to 91% (P<0.0001), with a slight decrease in paramedic on-scene to emergency department arrival time (34.5 [SD, 9.1] minutes versus 33.5 [SD, 10.3] minutes; P=0.045). The effects of routing were immediate and included an increase in proportion of receiving ASC care (from 17% to 88%; P<0.001) and a greater number of enrollments (18.6% increase) when comparing 12 months before and after regional stroke system implementation. Conclusions— The establishment of a regionalized emergency medical services system of acute stroke care dramatically increased the proportion of patients with acute stroke cared for at ASCs, from 1 in 10 to >9 in 10, with no clinically significant increase in prehospital care times and enhanced recruitment of patients into a prehospital treatment trial. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00059332.


European Journal of Neurology | 2017

Minocycline and matrix metalloproteinase inhibition in acute intracerebral hemorrhage: a pilot study

Jason J. Chang; May Kim-Tenser; Benjamin Emanuel; G. M. Jones; K. Chapple; A. Alikhani; Nerses Sanossian; Wendy J. Mack; Georgios Tsivgoulis; Andrei V. Alexandrov; T. Pourmotabbed

Intracerebral hemorrhage (ICH) is a devastating cerebrovascular disorder with high morbidity and mortality. Minocycline is a matrix metalloproteinase‐9 (MMP‐9) inhibitor that may attenuate secondary mechanisms of injury in ICH. The feasibility and safety of minocycline in ICH patients were evaluated in a pilot, double‐blinded, placebo‐controlled randomized clinical trial.


Journal of the American Heart Association | 2016

Trends in Transient Ischemic Attack Hospitalizations in the United States

Lucas Ramirez; May Kim-Tenser; Nerses Sanossian; Steven Cen; Ge Wen; Shuhan He; William J. Mack; Amytis Towfighi

Background Transient ischemic attack (TIA) is a major predictor of subsequent stroke. No study has assessed nation‐wide trends in hospitalization for TIA in the United States. Methods and Results Temporal trends in hospitalization for TIA (International Classification of Diseases, Ninth Revision code 435.0–435.9) from 2000 to 2010 were assessed among adults aged ≥25 years using the Nationwide Inpatient Sample. Age‐, sex‐, and race/ethnic‐specific TIA hospitalization rates were calculated using the weighted number of hospitalizations as the numerator and the US population as the denominator. Age‐adjusted rates were standardized to the 2000 US Census population. From 2000 to 2010, age‐adjusted TIA hospitalization rates decreased from 118 to 83 per 100 000 (overall rate reduction, −29.7%). Age‐specific TIA hospitalization rates increased for individuals aged 24 to 44 years (10–11 per 100 000), but decreased for individuals aged 45 to 64 (74 to 65 per 100 000), 65 to 84 (398 to 245 per 100 000), and ≥85 years (900 to 619 per 100 000). Blacks had the highest age‐adjusted yearly hospitalization rates, followed by Hispanics and whites (124, 82, and 67 per 100 000 in 2010). Rates slightly increased for blacks, but decreased for Hispanics and whites. Compared to women, age‐adjusted TIA hospitalization rates were lower and declined more steeply in men (132 to 89 per 100 000 versus 134 to 97 per 100 000). Conclusions Although overall TIA hospitalizations have decreased in the United States, the reduction has been more pronounced among older individuals, men, whites, and Hispanics. These findings highlight the need to target risk‐factor control among women, blacks, and individuals aged <45 years.

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Nerses Sanossian

University of Southern California

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William J. Mack

University of Southern California

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Steven Cen

University of Southern California

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Robin Conwit

National Institutes of Health

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Marc Eckstein

University of Southern California

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