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Biomedical subjects

Patrick Lyden

Publications and source records attributed to Patrick Lyden.

9 recordsLinked to original sources
PubMed2006

Additional outcomes and subgroup analyses of NXY-059 for acute ischemic stroke in the SAINT I trial.

BACKGROUND AND PURPOSE: NXY-059 is a free radical-trapping neuroprotectant demonstrated to reduce disability from ischemic stroke. We conducted analyses on additional end points and sensitivity analyses to confirm our findings. METHODS: We randomized 1722 patients with acute ischemic stroke to a 72-hour infusion of placebo or intravenous NXY-059 within 6 hours of stroke onset. The primary outcome was disability at 90 days, as measured by the modified Rankin Scale (mRS), a 6-point scale ranging from 0 (no residual symptoms) to 5 (bed-bound, requiring constant care). Additional and exploratory analyses included mRS at 7 and 30 days; subgroup interactions with final mRS; assessments of activities of daily living by Barthel index; and National Institutes of Health Stroke Scale (NIHSS) neurological scores at 7 and 90 days. RESULTS: NXY-059 significantly improved the distribution of the mRS disability score compared with placebo at 7, 30, and 90 days (Cochran-Mantel-Haenszel test P=0.002, 0.004, 0.038, respectively; 90-day common odds ratio 1.20; 95% CI, 1.01 to 1.42). The benefit was not attributable to any specific baseline characteristic, stratification variable or subgroup interaction. Neurological scores were improved at 7 days (odds ratio [OR], 1.46; 95% CI, 1.13, 1.89; P=0.003) and the Barthel index was improved at 7 and 30 days (OR, 1.55; 95% CI, 1.22, 1.98; P<0.0001; OR, 1.27; 95% CI, 1.01, 1.59; P=0.02). CONCLUSIONS: NXY-059 within 6 hours of acute ischemic stroke significantly reduced disability. Benefit on neurological scores and activities of daily living was detectable early but not significant at 90 days; however, our trial was underpowered to measure effects on the neurological examination. The benefit on disability is not confounded by interactions and is supported by other outcome measures.

Aged↗
PubMed2006

NXY-059 for acute ischemic stroke.

BACKGROUND: NXY-059 is a free-radical-trapping agent that is neuroprotective in animal models of stroke. We tested whether it would reduce disability in humans after acute ischemic stroke. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 1722 patients with acute ischemic stroke who were randomly assigned to receive a 72-hour infusion of placebo or intravenous NXY-059 within 6 hours after the onset of the stroke. The primary outcome was disability at 90 days, as measured according to scores on the modified Rankin scale for disability (range, 0 to 5, with 0 indicating no residual symptoms and 5 indicating bedbound, requiring constant care). RESULTS: Among the 1699 subjects included in the efficacy analysis, NXY-059 significantly improved the overall distribution of scores on the modified Rankin scale, as compared with placebo (P=0.038 by the Cochran-Mantel-Haenszel test). The common odds ratio for improvement across all categories of the scale was 1.20 (95 percent confidence interval, 1.01 to 1.42). Mortality and rates of serious and nonserious adverse events were each similar in the two groups. NXY-059 did not improve neurologic functioning as measured according to the National Institutes of Health Stroke Scale (NIHSS): the difference between the two groups in the change from baseline scores was 0.1 point (95 percent confidence interval, -1.4 to 1.1; P=0.86). Likewise, no improvement was observed according to the Barthel index (P=0.14). In a post hoc analysis of patients who also received alteplase, NXY-059 was associated with a lower incidence of any hemorrhagic transformation (P=0.001) and symptomatic intracranial hemorrhage (P=0.036). CONCLUSIONS: The administration of NXY-059 within six hours after the onset of acute ischemic stroke significantly improved the primary outcome (reduced disability at 90 days), but it did not significantly improve other outcome measures, including neurologic functioning as measured by the NIHSS score. Additional research is needed to confirm whether NXY-059 is beneficial in ischemic stroke. (ClinicalTrials.gov number, NCT00119626.).

Acute Disease↗
PubMed2005

NIHSS training and certification using a new digital video disk is reliable.

BACKGROUND AND PURPOSE: NIH Stroke Scale certification is required for participation in modern stroke clinical trials and as part of good clinical care in stroke centers. The existing training and certification videotapes, however, are more than 10 years old and do not contain an adequate balance of patient findings. METHODS: After producing a new NIHSS training and demonstration DVD, we selected 18 patients representing all possible scores on 15 scale items for a new certification DVD. Patients were divided into 3 certification groups of 6 patients each, balanced for lesion side, distribution of scale item findings, and total score. We sought to measure interrater reliability of the certification DVD using methodology previously published for the original videotapes. Raters were recruited from 3 experienced stroke centers. Each rater watched the new training DVD and then evaluated one of the 3 certification groups. RESULTS: Responses were received from 112 raters: 26.2% of all responses came from stroke nurses, 34.1% from emergency departments/other physicians, and 39.6% from neurologists. One half (50%) of raters were previously NIHSS-certified. Item responses were tabulated, scoring performed as previously published, and agreement measured with unweighted kappa coefficients for individual items and an intraclass correlation coefficient for the overall score. kappa ranged from 0.21+/-0.05 (ataxia) to 0.92+/-0.09 (LOC-C questions). Of 15 items, 2 showed poor, 11 moderate, and 2 excellent agreement based on kappa scores. The intraclass correlation coefficient for total score was 0.94 (95% confidence interval, 0.84 to 1.00). Reliability scores were similar among specialists and centers, and there were no differences between nurses and physicians. kappa scores trended higher among raters previously certified. CONCLUSIONS: These certification DVDs are reliable for NIHSS certification, and scoring sheets have been posted on a web site for real-time, online certification.

Cerebrovascular Disorders↗
PubMed2005

The impact of imbalances in baseline stroke severity on outcome in the National Institute of Neurological Disorders and Stroke Recombinant Tissue Plasminogen Activator Stroke Study.

STUDY OBJECTIVE: The National Institute of Neurological Disorders and Stroke (NINDS) Recombinant Tissue Plasminogen Activator (rtPA) Stroke Study demonstrated a clinically meaningful and statistically significant benefit of tissue plasminogen activator (tPA). Adjusting for the baseline National Institutes of Health (NIH) Stroke Scale, the benefit of tPA remained. However, other authors suggest that an imbalance in baseline stroke severity between the tPA and placebo groups confounded the results. Another issue that has been raised concerns a possible increase in early mortality for individuals given tPA. In post hoc subgroup analysis, we describe the effect of tPA across a spectrum of time from stroke onset to treatment and stroke severity subgroups. Stroke severity was based on the NIH Stroke Scale. We also compare early mortality (2-week and 30-day) in the tPA and placebo groups. METHODS: Using combined data from the 2 NINDS rtPA Stroke Study trials, we performed post hoc subgroup analyses of 3-month favorable outcome (defined by the NIH Stroke Scale, Barthel, Rankin, and Glasgow Outcome Scales). We categorized patients from the trials into onset to treatment (0 to 90 minutes, 91 to 180 minutes) by NIH Stroke Scale (< or =5, 6 to 20, >20) subgroups. Analyses were adjusted for all variables previously shown to be associated with favorable outcome at 3 months. We also compared early mortality within onset-to-treatment subgroups. RESULTS: For all the 12 specified onset-to-treatment-NIH Stroke Scale subgroups, the adjusted odds ratio for a favorable 3-month outcome was greater than 1.0 and favored tPA. We detected no difference in mortality between patients treated with rtPA and those treated with placebo by 2 weeks posttreatment (rtPA=9%, placebo=13%; P =.49) or by 30 days (rtPA=11%, placebo=16%; P =.30). CONCLUSION: These are descriptive post hoc subgroup analyses. Using cut points defined in previous critiques of the NINDS trials, these analyses give results consistent with previous NINDS Study Group reports. Baseline NIH Stroke Scale imbalance does not account for the better outcome of rtPA-treated patients.

Brain Ischemia↗
PubMed2004

Association of outcome with early stroke treatment: pooled analysis of ATLANTIS, ECASS, and NINDS rt-PA stroke trials.

BACKGROUND: Quick administration of intravenous recombinant tissue plasminogen activator (rt-PA) after stroke improved outcomes in previous trials. We aimed to analyse combined data for individual patients to confirm the importance of rapid treatment. METHODS: We pooled common data elements from six randomised placebo-controlled trials of intravenous rt-PA. Using multivariable logistic regression we assessed the relation of the interval from stroke onset to start of treatment (OTT) on favourable 3-month outcome and on the occurrence of clinically relevant parenchymal haemorrhage. FINDINGS: Treatment was started within 360 min of onset of stroke in 2775 patients randomly allocated to rt-PA or placebo. Median age was 68 years, median baseline National Institute of Health Stroke Scale (NIHSS) 11, and median OTT 243 min. Odds of a favourable 3-month outcome increased as OTT decreased (p=0.005). Odds were 2.8 (95% CI 1.8-4.5) for 0-90 min, 1.6 (1.1-2.2) for 91-180 min, 1.4 (1.1-1.9) for 181-270 min, and 1.2 (0.9-1.5) for 271-360 min in favour of the rt-PA group. The hazard ratio for death adjusted for baseline NIHSS was not different from 1.0 for the 0-90, 91-180, and 181-270 min intervals; for 271-360 min it was 1.45 (1.02-2.07). Haemorrhage was seen in 82 (5.9%) rt-PA patients and 15 (1.1%) controls (p<0.0001). Haemorrhage was not associated with OTT but was with rt-PA treatment (p=0.0001) and age (p=0.0002). INTERPRETATION: The sooner that rt-PA is given to stroke patients, the greater the benefit, especially if started within 90 min. Our results suggest a potential benefit beyond 3 h, but this potential might come with some risks.

Aged↗
PubMed2004

Factor analysis of the National Institutes of Health Stroke Scale in patients with large strokes.

BACKGROUND: The National Institutes of Health Stroke Scale (NIHSS) was created to detect treatment-related differences in clinical trials and was designed to measure right- and left-sided cerebral hemispheric function. OBJECTIVE: To validate the original design in patients with very large strokes. DESIGN: A previously published factor structure was fit to the data. Then, a new analysis was conducted to explore the underlying structure of the scale in this population. Finally, NIHSS scores and infarction volumes were compared. SETTING: The Clomethiazole for Acute Stroke Study-Ischemic, conducted in academic and community hospitals. PATIENTS: Individuals with acute stroke seen within 12 hours of onset. Of 1191 records available, 98% had complete NIHSS scores. MAIN OUTCOME MEASURE: Goodness-of-fit statistic (Bentler) for each factor solution. RESULTS: Two factors were found underlying the NIHSS, corresponding to the left and right hemispheres (goodness of fit = 0.97), using the previously published factor analysis. The new exploratory analysis also suggested 2 factors representing left and right brain function. The median (range) NIHSS scores were 15 (5-25) for right brain strokes and 19 (6-32) for left brain strokes (P<.001). The median (range) infarction volumes were 56.2 mL (0.1-381.5 mL) for right brain strokes and 37.8 mL (0.2-255.1 mL) for left brain strokes (P<.001). The correlation coefficient between NIHSS score and lesion volume was 0.37 (P<.001). CONCLUSIONS: The underlying structure of the NIHSS conforms to cerebral hemispheric lateralization, confirming previous findings in a new population of large hemispheric strokes. Left- brain strokes score 4 points higher on the NIHSS than right brain strokes of larger volume.

Acute Disease↗
PubMed2003

Population pharmacokinetics of clomethiazole and its effect on the natural course of sedation in acute stroke patients.

AIMS: This analysis was performed to investigate the population pharmacokinetics of clomethiazole and its effect on the natural course of sedation in acute stroke patients using a nonlinear mixed effects modelling approach. METHODS: One thousand five hundred and forty-six acute stroke patients (774 on active treatment) from 166 centres were included in three randomized, double-blind, placebo-controlled phase III efficacy and safety studies. A total dose of 68 mg kg(-1) clomethiazole edisilate was given as a three-phase i.v.-infusion over 24 h. Three blood samples were drawn from all patients to characterize the pharmacokinetics. Sedation was monitored throughout the entire treatment period and the degree of sedation was measured on a discrete ordinal scale with six levels. Models were fitted to the data using the software NONMEM. RESULTS: Clomethiazole was characterized by a two-compartment pharmacokinetic model with interindividual variability in all structural parameters. For a patient weighing 75 kg, the average CL, V1, Q, and V2 was estimated to be 52.7 l h(-1), 82.5 l, 167 l h(-1) and 335 l, respectively. The interindividual variability in CL, V1, Q and V2 was estimated to be 48%, 53%, 42% and 54%, respectively. Increasing body weight and concomitant administration of liver enzyme inducing drugs were found to increase clearance (by 0.5 l h(-1) kg(-1) and 40%, respectively). Increasing weight also increased the volume of distribution (1.1 l kg(-1) for V1 and 4.7 l kg(-1) for V2). A six-category proportional odds model with a component including the natural course of sedation following placebo administration, a drug component (present or absent) and an interindividual variability component described the degree of sedation. Stroke severity as measured on the NIH-stroke scale on admission and drug treatment were the most important predictors of sedation, but a nonlinear increase in sedation with increasing age was also found. Increasing body weight increased the sedative drug effect. CONCLUSIONS: The pharmacokinetics of clomethiazole were characterized in acute stroke patients and the analysis excluded several possible covariates of interest in drug development. The time course of sedation could be quantitatively described during the first 24 h following an acute stroke in the presence or absence of clomethiazole treatment.

Adult↗