Severe disability at hospital discharge in ischemic stroke survivors

Influence of stroke infarct location on functional outcome measured by the modified rankin scale

BACKGROUND AND PURPOSE

In the early days after ischemic stroke, information on structural brain damage from MRI supports prognosis of functional outcome. It is rated widely by the modified Rankin Scale that correlates only moderately with lesion volume. We therefore aimed to elucidate the influence of lesion location from early MRI (days 2-3) on functional outcome after 1 month using voxel-based lesion symptom mapping.

METHODS

We analyzed clinical and MRI data of patients from a prospective European multicenter stroke imaging study (I-KNOW). Lesions were delineated on fluid-attenuated inversion recovery images on days 2 to 3 after stroke onset. We generated statistic maps of lesion contribution related to clinical outcome (modified Rankin Scale) after 1 month using voxel-based lesion symptom mapping.

RESULTS

Lesion maps of 101 patients with middle cerebral artery infarctions were included for analysis (right-sided stroke, 47%). Mean age was 67 years, median admission National Institutes of Health Stroke Scale was 11. Mean infarct volumes were comparable between both sides (left, 37.5 mL; right, 43.7 mL). Voxel-based lesion symptom mapping revealed areas with high influence on higher modified Rankin Scale in regions involving the corona radiata, internal capsule, and insula. In addition, asymmetrically distributed impact patterns were found involving the right inferior temporal gyrus and left superior temporal gyrus.

CONCLUSIONS

In this group of patients with stroke, characteristic lesion patterns in areas of motor control and areas involved in lateralized brain functions on early MRI were found to influence functional outcome. Our data provide a novel map of the impact of lesion localization on functional stroke outcome as measured by the modified Rankin Scale.

Are higher total serum cholesterol levels associated with better long-term motor function after ischemic stroke?

OBJECTIVES

The objective of the study was to investigate the prognostic role of total cholesterol (TC) level on the long-term motor function after ischemic stroke.

METHODS

One hundred and fourteen patients with ischemic stroke were included and divided into high total cholesterol (HTC; TC ≧5.18 mmol/l or ≧200 mg/dl) and low total cholesterol (LTC; TC <5.18 mmol/l or <200 mg/dl) groups. The motor outcome was evaluated using the motor score of the Fugl-Meyer assessment (MFMA) at 2 weeks (baseline), 1, 3, 6, and 12 months after stroke. Prognostic factors on the repeated measurements of the MFMA were investigated using the linear mixed regression model.

RESULTS

The TC, basal ganglion lesion, baseline MFMA, first-time stroke, and follow-up time were identified as significant predictors for serial MFMA scores. The HTC group had higher MFMA scores than the LTC group by 2.72 units (95% confidence interval (CI): 0.17, 5.27, P = 0.037). An elevation of one unit of baseline MFMA led to a 0.86 increase (95% CI: 0.82, 0.90, P < 0.001) of subsequent MFMA scores. Subjects with basal ganglion lesions had lower MFMA scores by -3.55 (95% CI: -5.97, -1.14, P = 0.004).

DISCUSSION

Higher total cholesterol at the acute phase of ischemic stroke is a favorable prognostic factor for long-term motor function.

The role of CT perfusion imaging in acute stroke diagnosis: a large single-center experience

The objective of this study was to determine the utility of computed tomography perfusion (CTP) scans in diagnosing acute ischemic stroke (AIS). CTP abnormalities in two contiguous supratentorial levels were correlated with diffusion weighted image (DWI) abnormalities on magnetic resonance imaging (the standard for stroke diagnosis) performed within 1 week in 422 suspected acute ischemic strokes. Of 157 AIS confirmed by DWI, 78 showed CTP abnormalities (sensitivity 49.7%). All of these examinations were performed with a mean of 35 min from the initial emergency department neurological examination. Excluding small non-vascular territory strokes left 77 AIS with a total volume of infarcted tissue of more than 5 cc by DWI. Of these, 71 showed CTP abnormalities (sensitivity 92.2%). Of the 265 patients without AIS, none showed CTP abnormalities (specificity 100%). CTP is a rapid, readily available and effective method of diagnosing AIS in clinical practice, particularly the major intracranial vessel strokes that result in a more devastating outcome.

Is improvement in impaired cognition and depressive symptoms in post-stroke patients associated with recovery in activities of daily living?

BACKGROUND AND PURPOSE

Depression and cognitive impairment after stroke are associated with physical functional outcomes, but there are limited data on whether depressive symptoms and cognitive status and improvements independently influence functional status and recovery.

METHODS

In a 6-month prospective cohort study of 141 post-acute stroke patients, demographic and clinical data on admission, and neurological, cognitive, depressive symptoms and functional variables on admission and at 6 months after stroke were measured using the National Institute of Health Stroke Scale (NIHSS), Abbreviated Mental Test (AMT), Geriatric Depression Scale (GDS) and Barthel Index (BI).

RESULTS

On multivariate analysis, severe activities of daily living (ADL) dependence at 6 months was significantly less likely associated with higher baseline AMT score denoting better cognitive status (OR=0.68, 95% CI 0.48-0.97 per score point) and with greater AMT change score denoting greater cognitive improvement (OR=0.61, 95% CI 0.41-0.91 per change score point); it was also more likely with higher baseline NIHSS scores denoting severe neurological impairment, (OR=1.74, 95% CI 1.13-2.63 per point score), NIHSS change score [denoting lesser neurological improvement (OR = 1.83, 95% CI 1.13-2.93 per unit change score)], but was not associated with baseline or change scores of GDS. Greater magnitudes of functional recovery [BI change score (standardized beta)] were associated with better baseline depressive symptoms (-0.21) and improvement (-0.31), but not with cognitive status or improvement, in the presence of other significant variables, neurological status (-0.89) and improvement (-0.65), lower baseline physical functional status (-0.85) and younger age (-0.23).

CONCLUSIONS

These data suggest that improving depressive symptoms in stroke patients may accelerate functional recovery, but the level of physical functioning achieved post-stroke is determined by neurological and cognitive factors, consistent with the evidence that improvement of depressive symptoms through therapeutic intervention is limited by cognitive impairment.

Outcomes validity and reliability of the modified Rankin scale: implications for stroke clinical trials: a literature review and synthesis

BACKGROUND AND PURPOSE

The modified Rankin scale (mRS), a clinician-reported measure of global disability, is widely applied for evaluating stroke patient outcomes and as an end point in randomized clinical trials. Extensive evidence on the validity of the mRS exists across a large but fragmented literature. As new treatments for acute ischemic stroke are submitted for agency approval, an appreciation of the mRS's attributes, specifically its relationship to other stroke evaluation scales, would be valuable for decision-makers to properly assess the impact of a new drug on treatment paradigms. The purpose of this report is to assemble and systematically assess the properties of the mRS to provide decision-makers with pertinent evaluative information.

METHODS

A Medline search was conducted to identify reports in the peer-reviewed medical literature (1957-2006) that provide information on the structure, validation, scoring, and psychometric properties of the mRS and its use in clinical trials. The selection of articles was based on defined criteria that included relevance, study design and use of appropriate statistical methods.

RESULTS

Of 224 articles identified by the literature search, 50 were selected for detailed assessment. Inter-rater reliability with the mRS is moderate and improves with structured interviews (kappa 0.56 versus 0.78); strong test-re-test reliability (kappa=0.81 to 0.95) has been reported. Numerous studies demonstrate the construct validity of the mRS by its relationships to physiological indicators such as stroke type, lesion size, perfusion and neurological impairment. Convergent validity between the mRS and other disability scales is well documented. Patient comorbidities and socioeconomic factors should be considered in properly applying and interpreting the mRS. Recent analyses suggest that randomized clinical trials of acute stroke treatments may require a smaller sample size if the mRS is used as a primary end point rather than the Barthel Index.

CONCLUSIONS

Multiple types of evidence attest to the validity and reliability of the mRS. The reported data support the view that the mRS is a valuable instrument for assessing the impact of new stroke treatments.

Neurologic and non-neurologic predictors of mortality in ischemic stroke patients admitted to the intensive care unit

BACKGROUND/PURPOSE

Patients with severe strokes may have different associated medical comorbidities from those with mild strokes. This study evaluated the neurologic and non-neurologic medical predictors of mortality in patients with severe cerebral infarction in the acute stage.

METHODS

Patients admitted to a neurologic intensive care unit (ICU) due to cerebral infarction were included. Neurologic and non-neurologic predictors for in-unit mortality were determined by logistic regression analyses. Two models using (A) neurologic factors and (B) combined neurologic and non-neurologic factors as mortality predictors were developed. The performance of the models in predicting overall, neurologic and non-neurologic mortalities was compared by areas under the receiver-operating characteristic curves (AUC) of the derived regressive equations.

RESULTS

Of 231 patients with cerebral infarction admitted to the ICU, 34 (14.7%) died during ICU stay. Conscious state and acute physiologic abnormalities were significant predictors of mortality. The length of ICU stay in patients with non-neurologic mortality was longer than in those with neurologic mortality (p = 0.044). The AUC of Model B was larger than that of Model A in predicting overall (0.768 +/- 0.045 vs. 0.863 +/- 0.033, p = 0.005) and non-neurologic mortalities (0.570 +/- 0.073 vs. 0.707 +/- 0.074, p = 0.009), while there was no difference in predicting death from neurologic causes (0.858 +/- 0.044 vs. 0.880 +/- 0.032, p = 0.217).

CONCLUSION

Impaired consciousness and acute physiologic abnormalities are independent predictors of mortality for severe ischemic stroke during the acute stage. Neurologic factors predict early mortality from intrinsic cerebral dysfunction, while non-neurologic factors, especially the associated physiologic abnormalities, predict late mortality from medical complications.

Critical Appraisal and Review of the Rankin Scale and Its Derivatives

BACKGROUND AND PURPOSE

Efforts to reduce stroke burden require accurate assessment of outcomes in order to compare treatments. The Rankin Scale and its derivatives, the Modified Rankin Scale and the Oxford Handicap Scale, taken together, are among the most common outcome measures that have been used in stroke research. The aim of this study was to perform a critical appraisal of the clinimetric properties of these scales. It was also planned to review the use of these scales in a selection of articles to illustrate concerns raised by the critical appraisal.

SUMMARY OF REVIEW

A literature search was performed using electronic databases to locate relevant articles about the reviewed scales. The scales were appraised using a structured format regarding the following properties: purpose, development, presentation, language, method of administration, content validity, face validity, feasibility, construct validity, reliability, responsiveness, and generalizability. There are concerns in each of the appraised areas regarding the clinimetric properties of these scales.

CONCLUSION

Further work is needed to improve the clinimetric properties of the reviewed scales to ensure that they are more useful tools in determining the outcome of stroke. Alternatively, a newer global outcome scale with improved clinimetric properties may be a better option for future stroke research.

Outcome in patients with stroke associated with internal carotid artery occlusion

BACKGROUND

The clinical outcome in patients with stroke associated with internal carotid artery (ICA) occlusion is poor, although a minority may recover without dependency. The purposes of this study were (1) to assess the predictive factors of adverse outcome in patients with stroke associated with an occlusion of the ICA and (2) to evaluate the rate of spontaneous recanalization of an occluded ICA.

METHODS

A total of 177 consecutive patients with first-ever ischemic stroke associated with ICA occlusion were prospectively examined from the Perugia Stroke Registry. Mean age was 71.4 +/- 14.3 years; 53% were males. Multiple regression models were used to analyze predictors of mortality, dependency and ipsilateral stroke recurrence.

RESULTS

The most probable cause of occlusion was atherosclerosis in 65%, cardioembolism in 22%, dissection in 9% and other causes in 4%. Thirty percent of the patients died within 30 days. After a mean follow-up of 420 days (range 1-1,970 days), 45% of the patients had died and 75% had died or were disabled. Another 6% of the patients had a recurrent stroke ipsilateral to the occluded carotid artery. Age was the only predictor of 30-day mortality (77.7 +/- 9.7 vs. 68.7 +/- 15.2 years; p = 0.03) and of long-term mortality or disability (p < 0.003). Hypertension (OR 0.42; 95% CI 0.17-1.00; p = 0.05) was associated with a better outcome within 30 days from stroke onset. Previous ipsilateral transient ischemic attack (OR 0.24; 95% CI 0.06-0.89; p = 0.03) and hyperlipidemia (OR 0.38; 95% CI 0.15-0.99; p = 0.049) were predictors of a better outcome with respect to long-term mortality or disability. No predictors of ipsilateral stroke recurrence were found. One hundred and five out of 177 patients had adequate follow-up ultrasound data. After a mean follow-up of 1.8 years, 10 patients had recanalization of the occluded ICA (2/71 atherosclerosis, 3/19 cardioembolism and 5/15 dissection).

CONCLUSIONS

After a mean follow-up of 1.2 years, 45% of the patients with stroke associated with ICA occlusion had died, while 75% had died or were functionally dependent. The presence of either previous ipsilateral transient ischemic attack, hypertension or hyperlipidemia was associated with a favorable outcome. Recanalization of an occluded ICA occurred in a minority of patients and it was associated with cardioembolism and with arterial dissection.

Unenhanced CT and Acute Stroke Physiology

Unenhanced CT remains the most widely used imaging technique and is the standard of care for acute stroke evaluation. Early ischemic signs (EIS) within the first 3 to 6 hours of symptom onset (eg, parenchymal hypodensity, sulcal effacement, and dense vessel) have been advocated as a triage tool for thrombolytic therapy. Recent studies have challenged the relevance of these EIS within 3 hours of stroke onset, with advanced MR and CT methods increasingly competing with unenhanced CT as the primary imaging modality for acute ischemia. Nonetheless, the insights regarding acute stroke physiology provided by studying the CT evolution of early ischemic signs continue to be valuable for the informed interpretation of all stroke images. It is these insights that comprise the topic of this article.

Factors affecting the quality of life after ischemic stroke: young versus old patients

Background

Factors affecting the quality of life (QOL) may be different between young and old stroke patients. However, these issues have not yet been properly investigated.

Methods

We identified 170 young-onset stroke patients (onset between 15 and 45 years of age) who were admitted to the Asan Medical Center. Three hundred and forty follow-up period matched, old-onset stroke patients (onset >45 years of age) were chosen as a control group. A follow-up interview was performed 1~5 years after the onset of stroke in 96 young patients and 160 old patients. With the use of standardized questionnaire, we assessed physical disabilities, activity of daily living (Barthel Index Score, modified Rankin scale), the presence of depression (using DSM IV criteria and Beck Depression Inventory) and socio-economic/job status. The QOL was assessed using the Stroke Specific QOL developed by Williams et al.

Results

The QOL scores were significantly higher in young patients than in old ones. Univariate analysis showed that factors related to low QOL included unemployment, motor impairment, aphasia, dysarthria, dysaphagia and severe modified Rankin score in young patients while poor economic status, unemployment, supratentorial (vs. infratentorial) stroke, anterior (vs. posterior) circulation stroke, the presence of diabetes mellitus, motor impairment, aphasia, dysarthria, dysphagia, visual field defect, severe modified Rankin score, the presence of post-stroke seizures and depression were related to the low QOL in old patients. Cigarette smoking (in old patients) and alcohol drinking (in both young and old patients) were related to high QOL. Multiple regression analysis showed that modified Rankin score was the most important factor explaining low QOL in both groups, while other important factors included depression, visual field defect and anterior circulation stroke in old patients, and the motor dysfunction and dysarthria in young patients.

Conclusions

We conclude that aside from modified Rankin scale, factors affecting the quality of life are different between these two groups. Recognition of these differences may allow us to develop different strategies to improve the quality of life in stroke patients.

Ischemic preconditioning increases antioxidants in the brain and peripheral organs after cerebral ischemia

BACKGROUND AND PURPOSE

Low molecular weight antioxidants (LMWA), which reflect tissue reducing power, are among the endogenous mechanisms for neutralizing reactive oxygen species (ROS). Ischemic preconditioning (IPC) was associated with decreased oxidative stress. We examined the effect of focal ischemia on LMWA and on prostaglandin E(2) (PGE(2), a product of arachidonic acid oxidation) in the brain, heart, liver, and lungs of rats subjected to 90 min of ischemia and in IPC rats subjected to similar insult.

METHODS

Transient right middle cerebral artery occlusion (MCAO) was performed for 90 min and at 0, 5, 30, 60, or 240 min of reperfusion, LMWA and PGE(2) were evaluated by cyclic voltametry (CV) and radioimmunoassay, respectively. IPC was induced by 2 min of MCAO, 24 h prior to the major ischemic episode.

RESULTS

LMWA decreased at 5 min of reperfusion in the brain, heart, liver, and lung and rose 4 h later only in the brain. PGE(2) levels increased three to fivefold in all tissues examined. Surprisingly, in IPC rats a dramatic increase of LMWA occurred at 5 min of reperfusion in the brain and in the peripheral organs. Uric acid, but not ascorbic, is the major LMWA increased.

CONCLUSIONS

We propose that after ischemia, ROS rapidly consume the antioxidants reserves in the brain and also in peripheral organs, suggesting that the whole body is under oxidative stress. Moreover, part of the neuroprotection afforded by IPC is mediated by the brain's ability to mobilize antioxidants, especially uric acid, that attenuate the massive ROS-mediated oxidative stress.