Does Preexisting Antiplatelet Treatment Influence Postthrombolysis Intracranial Hemorrhage in Community‐treated Ischemic Stroke Patients? An Observational Study

Objectives Intracranial hemorrhage ( ICH ) after acute stroke thrombolysis is associated with poor outcomes. Previous investigations of the relationship between preexisting antiplatelet use and the safety of intravenous ( IV ) thrombolysis have been limited by low event rates. The objective of this study was to determine whether preexisting antiplatelet therapy increased the risk of ICH following acute stroke thrombolysis. The primary hypothesis was that antiplatelet use would not be associated with radiographic evidence of ICH after controlling for relevant confounders. Methods Consecutive cases of thrombolysis patients treated in the emergency department (ED) were identified using multiple methods. Retrospective data were collected from four hospitals from 1996 to 2004 and 24 other hospitals from 2007 to 2010 as part of a cluster‐randomized trial. The same chart abstraction tool was used during both time periods, and data were subjected to numerous quality control checks. Hemorrhages were classified using a prespecified methodology: ICH was defined as presence of hemorrhage in radiographic interpretations of follow‐up imaging (primary outcome). Symptomatic ICH ( sICH ) was defined as radiographic ICH with associated clinical worsening. A multivariable logistic regression model was constructed to adjust for clinical factors previously identified to be related to postthrombolysis ICH. Sensitivity analyses were conducted where the unadjusted and adjusted results from this study were combined with those of previously published external studies on this topic via meta‐analytic techniques. Results There were 830 patients included, with 47% having documented preexisting antiplatelet treatment. The mean (± standard deviation [SD]) age was 69 (±15) years, and the cohort was 53% male. The unadjusted proportion of patients with any ICH was 15.1% without antiplatelet use and 19.3% with antiplatelet use (absolute risk difference = 4.2%, 95% confidence interval [CI] = −1.2% to 9.6%); for sICH this was 6.1% without antiplatelet use and 9% with antiplatelet use (absolute risk difference = 3.1%, 95% CI = −1% to 6.7%). After adjusting for confounders, antiplatelet use was not significantly associated with radiographic ICH (odds ratio [OR] = 1.1, 95% CI = 0.8 to 1.7) or sICH (OR = 1.3, 95% CI = 0.7 to 2.2). In patients 81 years and older, there was a higher risk of radiographic ICH (absolute risk difference = 11.9%, 95% CI = 0.1% to 23.6%). The meta‐analyses combined the findings of this investigation with previous similar work and found increased unadjusted risks of radiographic ICH (absolute risk difference = 4.9%, 95% CI = 0.7% to 9%) and sICH (absolute risk difference = 4%, 95% CI = 2.3% to 5.6%). The meta‐analytic adjusted OR of sICH for antiplatelet use was 1.6 (95% CI = 1.1 to 2.4). Conclusions The authors did not find that preexisting antiplatelet use was associated with postthrombolysis ICH or sICH in this cohort of community treated patients. Preexisting tobacco use, younger age, and lower severity were associated with lower odds of sICH . The meta‐analyses demonstrated small, but statistically significant increases in the absolute risk of radiographic ICH and sICH , along with increased odds of sICH in patients with preexisting antiplatelet use. Resumen ¿Influye el Tratamiento Antiagregante Previo en la Hemorragia Intracraneal tras la Trombolisis en los Pacientes con Ictus Isquémicos Tratados en la Comunidad? Un Estudio Observacional Objetivos La hemorragia intracraneal ( HIC ) tras la trombolisis de un ictus agudo se asocia con malos resultados. Los estudios previos de la relación entre el uso de antiagregantes y la seguridad de la trombolisis intravenosa ( IV ) han estado limitados por los porcentajes bajos de sucesos. El objetivo de este estudio fue determinar si el tratamiento antiagregante previo está asociado con la evidencia radiológica de HIC tras el control por los factores de confusión relevantes. Metodología Se identificaron los casos consecutivos de pacientes tratados con trombolisis en el SU de múltiples formas. Se recogieron los datos de forma retrospectiva de cuatro hospitales de 1996 a 2004 y de 24 hospitales distintos de 2007 a 2010 como parte de un ensayo clínico aleatorizado en racimos. Se utilizó la misma tabla resumen de historia clínica durante ambos periodos de tiempo y los datos fueron sometidos a numerosos controles de calidad. Las hemorragias se clasificaron siguiendo una metodología preestablecida: la HIC se definió como la presencia de hemorragia en las interpretaciones radiológicas de las imágenes de seguimiento (resultado primario); y la HIC sintomática ( HIC s) se definió como la HIC radiológica asociada con un empeoramiento clínico. Se construyó un modelo multivariable de regresión logística para ajustar los factores clínicos previamente identificados como relacionados con un la HIC tras la trombolisis. Los análisis de sensibilidad se realizaron mediante técnicas de metanálisis y se combinaron los resultados ajustados y no ajustados de esta investigación con los estudios externos previamente publicados en este tema. Resultados Se incluyeron 830 pacientes, de los cuales el 47% tenía documentado tratamiento antiagregante previo. La media de edad fue de 69 años, y el 53% eran varones. La proporción no ajustada de pacientes con cualquier tipo de HIC fue del 15,1% sin toma de antiagregante y del 19,3% con la toma de antiagregante (diferencia del riesgo absoluto 4,2%, IC 95% = −1,2% a 9,6%); y para las HIC s fue del 6,1% sin toma de antiagregantes y del 9% con la toma de antiagregantes (diferencia absoluta del riesgo 3,1%, IC 95% = −1% a 6,7%). Tras ajustar por los factores de confusión, la toma de antiagregantes no se asoció de forma significativa con la HIC radiológica ( OR 1,1, IC 95% = 0,8 a 1,7]) o HIC s ( OR 1,3, IC 95% = 0,7 a 2,2). En los pacientes de 81 años o más, hubo mayor riesgo de HIC radiológica (diferencia de riesgo absoluta 11,9%, IC 95% = 0,1% a 23,6%). El metanálisis que combinó los hallazgos de esta investigación con los trabajos similares previos encontró un riesgo no ajustado incrementado para la HIC radiológica (diferencia absoluta del riesgo 4,9%, IC 95% = 0,7% a 9%) y de HIC s (diferencia absoluta del riesgo 4%, IC 95% = 2,3% a 5,6%). La odds ratio ajustada del metanálisis de HIC s para los pacientes con tratamiento de antigregantes fue de 1,6 ( IC 95% = 1,1 a 2,4). Conclusiones Los autores no encontraron que la toma previa de antigregantes se asocie con la HIC o la HIC s tras la trombolisis en esta cohorte de pacientes tratados en la comunidad. El consumo previo de tabaco, la edad más joven y la menor gravedad se asociaron con odds ratio menores de HIC s. El metanálisis demostró un incremento bajo, aunque estadísticamente significativo, de riesgo absoluto de HIC radiológica o de HIC s, con una odds ratio aumentada de HIC s en los pacientes con toma previa de antiagregantes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96759/1/acem12077.pd

Trends in thrombolytic use for ischemic stroke in the United States

BACKGROUND: Although recombinant tissue plasminogen activator (tPA) improves outcomes from ischemic stroke, prior studies have found low rates of administration. Recent guidelines and regulatory agencies have advocated for increased tPA administration in appropriate patients, but it is unclear how many patients actually receive tPA. OBJECTIVE: To determine whether national rates of tPA use for ischemic stroke have increased over time. METHODS: We identified all patients with a primary diagnosis of ischemic stroke from years 2001 to 2006 in the National Hospital Discharge Survey (NHDS), a nationally representative sample of inpatient hospitalizations, and searched for procedure codes for intravenous thrombolytic administration. Clinical and demographic factors were obtained from the survey and multivariable logistic regression used to identify independent predictors associated with thrombolytic use. RESULTS: Among the 22,842 patients hospitalized with ischemic stroke, tPA administration rates increased from 0.87% in 2001 to 2.40% in 2006 ( P < 0.001 for trend). Older patients were less likely to receive tPA (adjusted odds ratio [OR] and 95% confidence interval [CI]; 0.4 [0.3-0.6] for patients ≥80 years vs. <60 years), as were African American patients (0.4 [0.3-0.7]). Larger hospitals were more likely to administer tPA (3.3 [2.0-5.6] in hospitals with at least 300 beds compared to those with 6-99 beds). CONCLUSIONS: Although tPA administration for ischemic stroke has increased nationally in recent years, the overall rate of use remains very low. Larger hospitals were more likely to administer tPA. Further efforts to improve appropriate administration of tPA should be encouraged, particularly as the acceptable time-window for using tPA widens. Journal of Hospital Medicine 2010. © 2010 Society of Hospital Medicine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78061/1/689_ftp.pd

Treating the acute stroke patient as an emergency: current practices and future opportunities

Developments in acute stroke therapy have followed advances in the understanding of the evolving pathophysiology in both ischaemic stroke and intracerebral haemorrhage (ICH). In ischaemic stroke, rapid reperfusion of the ischaemic penumbra with thrombolysis within 3 h of symptom onset is of proven benefit, but few patients currently receive therapy, mainly due to the short-time window and lack of stroke expertise. In ICH, a recent study indicated that a haemostatic agent can limit ongoing bleeding and improve outcomes when administered within 4 h of stroke onset. These advances in acute stroke therapy underlie the concept that ‘time is brain’ and that urgent intervention can limit cerebral damage. Neuroprotective therapy could offer the prospect of a greater proportion of stroke patients receiving treatment, potentially before imaging and even in the ambulance setting. Virtually all stroke patients would benefit from receiving multidisciplinary care in acute stroke units

Reperfusion injury following cerebral ischemia: pathophysiology, MR imaging, and potential therapies

INTRODUCTION: Restoration of blood flow following ischemic stroke can be achieved by means of thrombolysis or mechanical recanalization. However, for some patients, reperfusion may exacerbate the injury initially caused by ischemia, producing a so-called “cerebral reperfusion injury”. Multiple pathological processes are involved in this injury, including leukocyte infiltration, platelet and complement activation, postischemic hyperperfusion, and breakdown of the blood–brain barrier. METHODS/RESULTS AND CONCLUSIONS: Magnetic resonance imaging (MRI) can provide extensive information on this process of injury, and may have a role in the future in stratifying patients’ risk for reperfusion injury following recanalization. Moreover, different MRI modalities can be used to investigate the various mechanisms of reperfusion injury. Antileukocyte antibodies, brain cooling and conditioned blood reperfusion are potential therapeutic strategies for lessening or eliminating reperfusion injury, and interventionalists may play a role in the future in using some of these therapies in combination with thrombolysis or embolectomy. The present review summarizes the mechanisms of reperfusion injury and focuses on the way each of those mechanisms can be evaluated by different MRI modalities. The potential therapeutic strategies are also discussed

The third international stroke trial (IST-3) of thrombolysis for acute ischaemic stroke

<p>Abstract</p> <p>Background</p> <p>Intravenous recombinant tissue plasminogen activator (rt-PA) is approved for use in selected patients with ischaemic stroke within 3 hours of symptom onset. IST-3 seeks to determine whether a wider range of patients may benefit.</p> <p>Design</p> <p>International, multi-centre, prospective, randomized, open, blinded endpoint (PROBE) trial of intravenous rt-PA in acute ischaemic stroke. Suitable patients must be assessed and able to start treatment within 6 hours of developing symptoms, and brain imaging must have excluded intracerebral haemorrhage. With 1000 patients, the trial can detect a 7% absolute difference in the primary outcome. With3500 patients, it can detect a 4.0% absolute benefit & with 6000, (mostly treated between 3 & 6 hours), it can detect a 3% benefit.</p> <p>Trial procedures</p> <p>Patients are entered into the trial by telephoning a fast, secure computerised central randomisation system or via a secure web interface. Repeat brain imaging must be performed at 24–48 hours. The scans are reviewed 'blind' by expert readers. The primary measure of outcome is the proportion of patients alive and independent (Modified Rankin 0–2) at six months (assessed via a postal questionnaire mailed directly to the patient). Secondary outcomes include: events within 7 days (death, recurrent stroke, symptomatic intracranial haemorrhage), outcome at six months (death, functional status, EuroQol).</p> <p>Trial registration</p> <p>ISRCTN25765518</p

A systematic review of clinical trials of pharmacological interventions for acute ischaemic stroke (1955-2008) that were completed, but not published in full

<p>Abstract</p> <p>Background</p> <p>We assessed the prevalence, and potential impact of, trials of pharmacological agents for acute stroke that were completed but not published in full. Failure to publish trial data is to be deprecated as it sets aside the altruism of participants' consent to be exposed to the risks of experimental interventions, potentially biases the assessment of the effects of therapies, and may lead to premature discontinuation of research into promising treatments.</p> <p>Methods</p> <p>We searched the Cochrane Stroke Group's Specialised Register of Trials in June 2008 for completed trials of pharmacological interventions for acute ischaemic stroke, and searched MEDLINE and EMBASE (January 2007 - March 2009) for references to recent full publications. We assessed trial completion status from trial reports, online trials registers and correspondence with experts.</p> <p>Results</p> <p>We identified 940 trials. Of these, 125 (19.6%, 95% confidence interval 16.5-22.6) were completed but not published in full by the point prevalence date. They included 16,058 participants (16 trials had over 300 participants each) and tested 89 different interventions. Twenty-two trials with a total of 4,251 participants reported the number of deaths. In these trials, 636/4251 (15.0%) died.</p> <p>Conclusions</p> <p>Our data suggest that, at the point prevalence date, a substantial body of evidence that was of relevance both to clinical practice in acute stroke and future research in the field was not published in full. Over 16,000 patients had given informed consent and were exposed to the risks of therapy. Responsibility for non-publication lies with investigators, but pharmaceutical companies, research ethics committees, journals and governments can all encourage the timely publication of trial data.</p