Biomedical subjects

Tobias Back

Publications and source records attributed to Tobias Back.

9 recordsLinked to original sources

PubMed2006

Costs of acute stroke care on regular neurological wards: a comparison with stroke unit setting.

OBJECTIVES: Stroke unit care has been shown to be beneficial but costly. In an own previous study, the resource utilization of stroke unit care has been evaluated. Since the resource utilization on regular neurological wards is widely unknown, we determined the costs for acute stroke care on regular neurological wards to compare both treatment settings. METHODS AND PATIENTS: We included 253 consecutive in-patients with the diagnosis of ischemic stroke (IS), intracerebral hemorrhage (ICH) or transient ischemic attack (TIA) treated on regular wards at a German University Department of Neurology, between 1 January and 30 June 1998. The modified Rankin scale (mRS) was used to assess outcome. Costs of stroke care were calculated from the perspective of the healthcare provider (hospital) by using a bottom-up approach. Resource utilization was compared to stroke unit care as determined in a previous study. Prices of 2002 were used (in Euros). RESULTS: IS was present in 78% (n=196), TIA in 13% (n=34), and ICH in 9% (n=23) of patients. Length of stay was 11.1+/-8.9 (mean+/-S.D., IS), 11.1+/-6.5 (TIA), and 16.9+/-15.5 (ICH) days (p>0.05). Mean costs of stroke care were euro 3060 (US$ 3180) for TIA, euro 3070 (US$ 3200) for IS and euro 5210 (US$ 5430) for ICH (p<0.05, ICH versus IS and TIA). The highest costs were due to non-medical care (46%) and personnel (25%). The mRS improved during hospitalization from 3.0+/-1.6 to 2.2+/-1.8 (p<0.01). Compared to care on regular neurological wards, mean costs per admission with treatment on stroke units increased by 7.0%, mean costs per day by 15.6%. CONCLUSION: The comparison - considering a potential bias of patient selection - shows that acute stroke unit care is approximately 16% more costly than treatment on regular neurological wards due to higher resource use of personnel and diagnostic procedures. Stroke unit treatment tends to decrease post-acute in-patient care costs.

Acute Disease↗

PubMed2006

Arterial hypotension triggers perifocal depolarizations and aggravates secondary damage in focal brain injury.

Perifocal depolarizations (PFD) have been observed after traumatic brain injury, are known to disturb cerebrovascular reactivity and thus may contribute to the morphological consequences of brain injury. In this investigation, the role of PFD was studied in focal brain lesions with/without induction of delayed hypotension. Cerebral freeze lesions were induced in anesthetized normotensive rats that underwent perfusion fixation of brains 5 min, 4 h or 24 h after lesioning, respectively, to obtain quantitative histopathology. In additional groups, a 45-min period of moderate hypobaric hypotension was applied 15 min post-trauma and brains were perfusion fixed after 4 h or 24 h. In a second series, the direct current (DC) potential and cortical laser-Doppler flow (LDF) were measured adjacent to lesions under normotensive or hypotensive conditions. Sham procedures were carried out in rats that underwent hypotension alone. Lesioning resulted in a significant LDF decrease to 50% of baseline, further decreased during hypotension to less than 40% of control (P < 0.05). Sham animals had LDF values between 60 and 70% of control when subjected to hypotension. Focal brain injury always induced a negative DC shift shortly after lesioning. In 6 of 8 rats that underwent cold lesion plus hypotension, a second PFD was observed approximately 2.5 min after onset of hypotension accompanied by a relative LDF increase by 25 +/- 12%. Lesion expansion was significantly worsened by hypotension (8.19 +/- 0.56 mm(3) at 24 h) compared with normotensive rats (7.01 +/- 0.3 mm(3) at 24 h, P < 0.01). We conclude that hypotension triggers depolarizations by an ischemic mechanism that contributes to final tissue damage.

Analysis of Variance↗

PubMed2006

Status epilepticus after stroke is associated with increased long-term case fatality.

PURPOSE: The aim of this study was to determine the long-term case fatality of patients with a first episode of status epilepticus (SE group) of cerebrovascular etiology, as compared with that in acute stroke patients without SE (AS group). METHODS: Patients with SE who had been prospectively admitted to an epidemiologic study were retrospectively compared with a cohort of patients from the local stroke registry. The main outcome end point was overall survival. Survival curves were generated according to the Kaplan-Meier method and compared by using the log-rank test. An extended Cox model was used to examine the impact of patient group on the risk of death. Covariates considered potential confounders included age at diagnosis, sex, type of stroke, affected hemisphere, and localization of lesions. RESULTS: Of 166 patients who entered the study, 93 patients were in the SE group, and 73 patients were in the AS group; 53 SE patients and 35 AS patients died during the study. Patient group (SE vs. AS) showed no significant impact on survival (p=0.0832) in univariate analysis. In contrast, the results from a multivariable analysis suggest that after 6 months, patients with SE were at about twice the risk of death as were patients with AS [hazard ratio of 2.12 with 95% confidence interval, 1.04-4.32, p=0.0392]. CONCLUSIONS: The occurrence of SE in patients with cerebrovascular disease indicates a high risk of death within 3 years. In contrast, the case fatality risk attributable to recurrent status or seizures is lower.

Aged↗

PubMed2005

Long-term outcome after stroke: evaluating health-related quality of life using utility measurements.

BACKGROUND AND PURPOSE: As stroke mortality rates decline, individuals are increasingly likely to live with their residual impairments and disabilities. Therefore, the quality of poststroke life is 1 of the pivotal topics that have to be considered beneath the functional outcome. However, data on health-related quality of life (HRQoL) have been infrequently used in stroke trials. The purpose of this study was to examine the long-term outcome (4 years after stroke) of HRQoL and to identify the determinants of HRQoL in stroke survivors. METHODS: Seventy-seven patients were included who were admitted to the Department of Neurology, Philipps-University Marburg, after experiencing an ischemic stroke, a transient ischemic attack, or a hemorrhagic stroke. All patients were examined by a physician, and assessment was performed using a standardized questionnaire. HRQoL was assessed using the German version of the EuroQoL Index (EQ-5D) and the Health Utility Index 2 and 3 (HUI2/3). RESULTS: Four years after stroke, besides physical functioning, neuropsychological sequelae such as depression and cognitive impairment contributed to a reduced HRQoL. In addition, the incidence of incontinence proved to be an important factor for HRQoL. Explained variances in regression analysis models were high (R2=0.802 for HUI and 0.633 for EQ-5D--visual analogue scale) and were based on a few important determinants, including physical state, depression, cognitive impairment, and incontinence. CONCLUSIONS: Our results underscore the importance of nonmotor symptoms on HRQoL in patients with stroke.

Activities of Daily Living↗

PubMed2005

Diffusion-weighted and perfusion MRI demonstrates parenchymal changes in complex partial status epilepticus.

Diffusion-weighted MRI (DWI) and perfusion MRI (PI) have been mainly applied in acute stroke, but may provide information in the peri-ictal phase in epilepsy patients. Both transient reductions of brain water diffusion, namely a low apparent diffusion coefficient (ADC), and signs of hyperperfusion have been reported in experimental and human epilepsy case studies. We studied 10 patients with complex partial status epilepticus (CPSE) with serial MRI including DWI and PI. All patients showed regional hyperintensity on DWI, and a reduction of the ADC in (i) the hippocampal formation and the pulvinar region of the thalamus (six out of 10 patients), (ii) the pulvinar and cortical regions (two out of 10), (iii) the hippocampal formation only (one out of 10), and (iv) the hippocampal formation, the pulvinar and the cortex (one out of 10). In all patients a close spatial correlation of focal hyperperfusion with areas of ADC/DWI change was present. In two patients hyperperfusion was confirmed in additional SPECT (single photon emission computed tomography) studies. All patients received follow-up MRI examinations showing partial or complete resolution of diffusion and perfusion abnormalities depending on the length of the follow-up interval. The clinical course, EEG and SPECT results all indicate that MRI detected changes related to prolonged epileptic activity. Combined PI and DWI can visualize haemodynamic and tissue changes after CPSE in the hippocampus, thalamus and affected cortical regions.

Adult↗

PubMed2004

Lesion evolution in cerebral ischemia.

There is sound evidence from histopathological and magnetic resonance imaging (MRI) studies that focal ischemic brain lesions tend to increase in size over time. Considerable lesion growth was observed in models of animal stroke as well as in patients presenting with hemispheric stroke. In focal cerebral ischemia, lesions predominantly enlarge early within 12 hours after onset. Ischemic injury is caused by complete necrosis in most of the affected tissue. By contrast, in global cerebral ischemia as seen after cardiac arrest, lesions appear late (>12 h) in selectively vulnerable brain regions such as the hippocampus, and neurons are damaged by apoptotic cell death. The high and regionally distinct vulnerability of the brain explains why prolonged periods of global ischemia result in widespread loss of energy metabolites combined with diffuse brain edema and global damage. Postulated mechanisms involved in lesion growth include among others excitotoxicity, periinfarct depolarizations, lactacidosis, microcirculatory disturbances, and flow-metabolism uncoupling. Research in the field faces two main challenges. First,maturation phenomena of injury may require special imaging techniques to detect early ischemic changes. Second, the dynamic nature of the changes underlines the need to conduct longitudinal studies with a variety of imaging techniques (e. g., metabolic imaging, diffusion/perfusion MRI, positron emission tomography) that require a differentiated interpretation of the alterations observed.

Animals↗

PubMed2003

Combined MR measurements of magnetization transfer, tissue diffusion and proton spectroscopy. A feasibility study with neurological cases.

Magnetic resonance imaging (MRI) of diffusion and magnetization transfer was combined with 1H-spectroscopic imaging (CSI) to evaluate the clinical potential of in-vivo profiles of various brain pathologies. Ten patients (multiple sclerosis, cerebrovascular disease, leukodystrophy, Alzheimer dementia) and five healthy volunteers were investigated with diffusion-weighted MRI, magnetization transfer imaging, and CSI. Proton spectra were analyzed as ratios of NAA/Cr and Cho/Cr calculated from the peak areas of N-acetylaspartate (NAA), (phospho)-creatine (Cr) and choline (Cho). The apparent diffusion coefficient (ADC) and the magnetization transfer ratio (MTR) were determined in identical voxels to ensure identical partial volume effects compared to CSI. Compared to MTR and ADC assessments, the lower spatial resolution of CSI clearly indicates a hindrance at 1.5 T. In most demyelinating lesions, NAA/Cr reduction paralleled attenuated MTRs and elevated ADCs. By contrast, in acute stroke and some acute MS lesions the ADC was reduced, while MTR and NAA/Cr were also decreased. In Alzheimer's dementia, ADC was increased, MTR unchanged and Cho/Cr increased. In a case of leukodystrophy, ADC was pronouncedly increased, MTR and NAA/Cr both reduced, and Cho/Cr normal. Combined measurements of ADC, MTR and CSI are feasible and provide differential in-vivo information on various brain pathologies.

Adult↗

PubMed2002

Timecourse of health-related quality of life as determined 3, 6 and 12 months after stroke. Relationship to neurological deficit, disability and depression.

OBJECTIVE: To study the timecourse of health-related global and domain-specific quality of life (QOL) in patients presenting with stroke or transient ischemic attacks (TIA) up to one year after the ischemic event. Variables were identified that may predict poststroke life satisfaction. PATIENTS AND METHODS: In this prospective study, a cohort of 183 stroke/TIA patients was followed up at 3, 6, and 12 months. A total of 144 survivors completed the follow-up (65 women, 79 men, mean age 65.3 years). Health-related QOL was assessed by the Short Form 36 (SF-36) questionnaire, the neurological status by the European Stroke Scale (ESS). Disability was evaluated by using the Barthel index and the modified Swedish Stroke Registry Follow-up Form; depression was scored by the Montgomery-Asberg Depression Rating Scale (MADRS). RESULTS: One year after stroke/TIA, 66 % of patients reported a worsening of life satisfaction compared with the prestroke level. The SF-36 physical component summary was reduced throughout the observation period. The SF-36 mental component summary deteriorated between the 6- and 12-months follow-up from 52.2 +/- 7.1 to 50.6 +/- 7.1 (p < 0.05). The SF-36 domains "physical functioning", "social functioning" and the MADRS scores both showed a significant deterioration between 6 and 12 months poststroke (p < 0.05). In contrast, the neurological status and the degree of disability remained stable. Male sex, absence of diabetes, and normal MADRS scores at 3 and 6 months postinsult were identified as predictors of favorable QOL after 1 year (p < 0.05). CONCLUSIONS: Despite stable neurologic function and disability, global as well as domain-specific measures of QOL deteriorated over the 12-months observation period in a cohort of stroke survivors.

Adult↗

PubMedDate not supplied

Resource utilization and costs of stroke unit care in Germany.

OBJECTIVES: Stroke imposes a considerable economic burden on the individual and society. Recently, the concept of an integrated stroke unit has been established in several countries to improve the outcome of patients. This study evaluates the costs of acute care of the different cerebrovascular insults in a stroke unit. METHODS: The study population included 340 patients who were consecutively admitted to the Department of Neurology, Philipps University Marburg, with the diagnosis of stroke or transient ischemic attack (TIA) between January 1 and June 30, 2000. Clinical status and course were evaluated by using the Barthel index and the modified Rankin scale. Employing a "bottom-up" approach, we calculated the costs from the perspective of the hospital and the third-party payer using data from provider departments and other published sources. RESULTS: Inpatient costs were 3020 euros (3290 US dollars) for TIA, 3480 euros (3790 US dollars) for ischemic stroke (IS), and 5080 euros (5540 US dollars) for intracerebral hemorrhage (ICH) and differed significantly among these subgroups (P < .05). Patient subgroups ranked in the same order for average length of stay at 9.4 days for TIA, 10.2 days for IS, and 11.9 days for ICH (P > .05). Approximately 30% of the hospital costs are due to physician charges and care. Imaging amounted to 10% and lab investigations to 14% of total costs, independent of the diagnosis. Postacute treatment, including inpatient rehabilitation, cost 9880 euros per patient. Across all diagnostic groups, a mean clinical improvement was observed at time of discharge. CONCLUSIONS: Care of patients with cerebrovascular events in a stroke unit causes a high demand of resources and has a considerable impact on health-care expenditure. Therefore, investigations comparing the stroke unit concept with other strategies in stroke care are necessary to evaluate the stroke unit concept for a rational use of available resources in patients with cerebrovascular events.

Aged↗