Accuracy of identifying acute stroke admissions in a Michigan Stroke Registry.

INTRODUCTION: The accurate identification of acute stroke cases is an essential requirement of hospital-based stroke registries. We determined the accuracy of acute stroke diagnoses in Michigan hospitals participating in a prototype of the Paul Coverdell National Acute Stroke Registry. METHODS: From May through November 2002, registry teams (ie, nurse and physician) from 15 Michigan hospitals prospectively identified all suspect acute stroke admissions and classified them as stroke or nonstroke. Medical chart data were abstracted for a random sample of 120 stroke and 120 nonstroke admissions. A blinded independent physician panel then classified each admission as stroke, nonstroke, or unclassifiable, and the overall accuracy of the registry was determined. RESULTS: The physician panel reached consensus on 219 (91.3%) of 240 admissions. The panel identified 105 stroke admissions, 93 of which had been identified by the registry teams (sensitivity = 88.6%). The panel identified 114 nonstroke admissions, all of which had been identified as nonstrokes by the registry teams (specificity = 100%). The positive and negative predictive value of the registry teams' designation was 100% and 90.5%, respectively. The registry teams' assessment of stroke subtype agreed with that of the panel in 78.5% of cases. Most discrepancies were related to the distinction between ischemic stroke and transient ischemic attack. CONCLUSION: The accuracy of hospitals participating in a hospital-based stroke registry to identify acute stroke admissions was very good; hospitals tended to underreport rather than to overreport stroke admissions. Stroke registries should periodically conduct studies to ensure that the accuracy of case ascertainment is maintained.

Changes in cerebral arterial pulsatility and hippocampal volume: a transcranial doppler ultrasonography study.

The physiological mechanisms of age-related cognitive decline remain unclear, in no small part due to the lack of longitudinal studies. Extant longitudinal studies focused on gross neuroanatomy and diffusion properties of the brain. We present herein a longitudinal analysis of changes in arterial pulsatility - a proxy for arterial stiffness - in two major cerebral arteries, middle cerebral and vertebral. We found that pulsatility increased in some participants over a relatively short period and these increases were associated with hippocampal shrinkage. Higher baseline pulsatility was associated with lower scores on a test of fluid intelligence at follow-up. This is the first longitudinal evidence of an association between increase in cerebral arterial stiffness over time and regional shrinkage.

Aging, vascular risk, and cognition: blood glucose, pulse pressure, and cognitive performance in healthy adults.

Advanced age is associated with decline in many areas of cognition as well as increased frequency of vascular disease. Well-described risk factors for vascular disease, such as diabetes and arterial hypertension, have been linked to cognitive deficits beyond those associated with aging. To examine whether vascular health indices such as fasting blood glucose levels and arterial pulse pressure can predict subtle deficits in age-sensitive abilities, the authors studied 104 healthy adults (ages 18 to 78) without diagnoses of diabetes or hypertension. Whereas results revealed a classic pattern of age-related differences in cognition, preprandial blood glucose level and pulse pressure independently and differentially affected cognitive performance. High-normal blood glucose levels were associated with decreased delayed associative memory, reduced accuracy of working memory processing among women, and slower working memory processing among men. Elevated pulse pressure was associated with slower perceptual-motor processing. Results suggest that blood glucose levels and pulse pressure may be sensitive indicators of cognitive status in healthy adults; however, longitudinal research is needed to determine whether such relatively mild elevations in this select group predict age-related cognitive declines.

Effect of pretreatment with statins on ischemic stroke outcomes.

BACKGROUND AND PURPOSE: Statins reduce the risk of stroke in at-risk populations and may improve outcomes in patients taking statins before an ischemic stroke (IS). Our objectives were to examine the effects of pretreatment with statins on poor outcome in IS patients. METHODS: Over a 6-month period all acute IS admissions were prospectively identified in 15 hospitals participating in a statewide acute stroke registry. Poor stroke outcome was defined as modified Rankin score >/=4 at discharge (ie, moderate-severe disability or death). Multivariable logistic regression models and matched propensity score analyses were used to quantify the effect of statin pretreatment on poor outcome. RESULTS: Of 1360 IS patients, 23% were using statins before their stroke event and 42% had a poor stroke outcome. After multivariable adjustment, pretreatment with statins was associated with lower odds of poor outcome (OR=0.74, 95% CI 0.52, 1.02). A significant interaction (P<0.01) was found between statin use and race. In whites, statins were associated with statistically significantly lower odds of poor outcome (OR=0.61, 95% CI 0.42, 0.86), but in blacks statins were associated with a nonstatistically significant increase in poor outcome (OR=1.82, 95% CI 0.98, 3.39). Matched propensity score analyses were consistent with the multivariable model results. CONCLUSIONS: Pretreatment with statins was associated with better stroke outcomes in whites, but we found no evidence of a beneficial effect of statins in blacks. These findings indicate the need for further studies, including randomized trials, to examine differential effects of statins on ischemic stroke outcomes among whites and blacks.

Lipid testing and lipid-lowering therapy in hospitalized ischemic stroke and transient ischemic attack patients: results from a statewide stroke registry.

BACKGROUND AND PURPOSE: Recent recommendations call for in-hospital initiation of lipid-lowering therapy (LLT) for most ischemic stroke (IS) and transient ischemic attack (TIA) survivors; however, little is known about actual use. This study describes use of and predictors for in-hospital lipid testing and LLT using data from a statewide stroke registry. METHODS: In 2002, the registry ascertained cases from a stratified sample of 16 hospitals. This study includes only IS and TIA cases discharged alive. RESULTS: In 1907 study subjects, 30.2% (27.2% to 33.5%) were on LLT at admission. In 1399 subjects not on LLT at admission, 37.2% (30.2% to 44.9%) underwent lipid testing, and 12.9% (7.2% to 22.1%) received LLT at discharge. Use of testing and LLT varied widely between hospitals (P<0.001). In-hospital lipid testing was positively associated with large teaching hospitals (P=0.029), and neurologist or neurosurgeon (P=0.004); and negatively associated with increasing age (P=0.002), being female (P=0.020), a previous medical history of atrial fibrillation (P=0.002), nonambulatory status (P=0.005), and poor prognosis (P<0.001). LLT at discharge was positively associated with a previous medical history of dyslipidemia (P<0.001), lipid testing (P=0.004), and elevated low-density lipoprotein levels (P<0.001). Among subjects who were not on LLT at admission but who had Adult Treatment Panel III-based indications for use of LLT, only 31.2% (20.5% to 44.5%) received LLT at discharge. CONCLUSIONS: Many hospitalized acute IS and TIA patients with indications for LLT are untreated at discharge. Efforts to close treatment gaps in lipid evaluation and treatment require sustained quality improvement efforts and should pay particular attention to high-risk patients.

Closing gaps between evidence-based stroke care guidelines and practices with a collaborative quality improvement project.

BACKGROUND: Michigan's prototype of the Paul Coverdell National Acute Stroke Registry revealed improvement opportunities in acute stroke care. METHODS: A partnership among the registry investigators, American Stroke Association (ASA), Michigan Department of Community Health, and 13 Michigan hospitals was implemented in 2004. The Institute for Healthcare Improvement Breakthrough Series model and the ASA's Get With The Guidelines-Stroke program and Patient Management Tool (PMT) were used to implement tailored stroke practice guidelines at each hospital. RESULTS: Significant improvements (p < .05) were observed for 5 of the 16 measures. Smoking cessation increased by 31%, dysphagia screening increased by 19%, use of the NIH stroke scale increased by 19%, documentation of reasons for not using recombinant tissue plasminogen activator (rt-PA) increased 13%, and documentation of dyslipidemia increased by 9%. DISCUSSION: Clinically and statistically significant improvements can be made in acute stroke care using a collaborative and systematic approach to QI that employs protocol utilization and ongoing data collection and review as part of an organized PMT.

Improved quality of stroke care for hospitalized Medicare beneficiaries in Michigan.

BACKGROUND AND PURPOSE: We reported previously that acute ischemic stroke patients encountered delays in obtaining neuroimaging and receiving thrombolysis, and that deep venous thrombosis prophylaxis was used only in a minority of eligible patients. We investigated whether these and other measures improved after a quality improvement initiative. METHODS: Medicare fee-for-service ischemic stroke and transient ischemic attack discharges in 136 acute care hospitals in Michigan were identified by International Classification of Diseases, 9th Revision, Clinical Modification codes. Only patients with stroke symptoms persisting for >1 hour and present on arrival were included in the analysis. Seven quality indicators were abstracted from chart review at baseline (discharges between July 1, 1998, and June 30, 1999) and at remeasurement (discharges between January 1, 2001, and June 30, 2001) after an intensive quality improvement initiative throughout Michigan hospitals. Quality indicators were compared at baseline and remeasurement. RESULTS: Indicators of care were determined in 5146 patients at baseline and 4980 patients on remeasurement. Four quality-of-care indicators showed significant improvement on remeasurement: antithrombotic prescribed at discharge (81.9 baseline versus 83.7% remeasurement; P=0.026), avoidance of sublingual nifedipine in patients with acute ischemic stroke (97.1 versus 99.7%; P<0.0001), documentation of a computed tomography (CT)/MRI during hospitalization (98.0 versus 99.1%; P=0.024), and appropriate deep venous thrombosis prophylaxis (13.8 versus 26.9%; P<0.0001). Time to CT/MRI did not significantly change, but time to thrombolysis improved (113 versus 88.5 minutes; P=0.045). CONCLUSIONS: Improvement occurred in several indicators of quality of care in Michigan Medicare beneficiaries presenting with acute stroke symptoms.

Stroke in the young in the northern Manhattan stroke study.

BACKGROUND AND PURPOSE: Stroke and stroke subtype incidence in young black and Hispanic populations have not been well studied. The purpose of this study was to determine stroke incidence rates in these populations and to compare rates among various race-ethnic, sex, and age groups. METHODS: A population-based incidence study identified all cases of first stroke in Northern Manhattan from 1993 to 1997. Stroke and stroke subtype incidence rates were calculated for younger (20 to 44 years of age) and older (>/=45 years of age) adults. The relative risk (RR) of stroke in blacks and Hispanics compared with whites was calculated. Stroke subtypes, infarct subtypes, and case fatality rates were compared in the young and old and in different race-ethnic groups and sexes. RESULTS: Over 4 years, 74 cases of first stroke in young patients were discovered (47% women, 12% black, 80% Hispanic, 8% white). The stroke incidence rates (cases per 100 000 persons per year) in the young were 23 overall, 10 for infarct, 7 for intracerebral hemorrhage (ICH), and 6 for subarachnoid hemorrhage. The RR of stroke in the young was greatest for blacks (2.4; 95% CI, 0.8 to 6.7) and Hispanics (2.5; 95% CI, 1.1 to 5.8) compared with whites. ICH was more frequent in men with a RR of 3.7 (95% CI, 1.4 to 10.1). Case fatality rates at 30 days were higher in blacks (38%) and Hispanics (16%) compared with whites (0%). CONCLUSIONS: Young blacks and Hispanics have greater stroke incidences than young whites.

Acute ischemic stroke in hospitalized medicare patients: evaluation and treatment.

BACKGROUND AND PURPOSE: This study describes several quality indicators of care in hospitalized stroke patients in Michigan from 1998 to 1999. SUMMARY OF REPORT: Median times from admission to head CT/MRI (89.5 minutes) and thrombolysis (113 minutes) exceeded recommended guidelines. Deep venous thrombosis prophylaxis was used in only 13.8% of eligible patients. CONCLUSIONS: Timing for brain imaging and acute ischemic stroke symptom onset need to be better documented, along with more provider education for routine deep venous thrombosis prophylaxis.

Stroke trials: what have we learned?

We reviewed the recent, major, therapeutic trials of intravenous thrombolytic therapy and ancrod for ischemic stroke. Randomized, controlled studies of acute ischemic stroke treatment were reviewed. Several post-FDA approval intravenous tPA studies were reviewed to understand the experience of this medication in practice. STAT trial was the major study using ancrod. Of multiple intravenous thrombolytic studies, the NINDS study of intravenous tPA was the only study to demonstrate a significantly higher percentage of patients with complete recovery or minimal deficit at three months. Studies in communities utilizing intravenous tPA for stroke illustrate the need for close adherence to the NINDS study protocol or else the risk of tPA use may exceed the benefits.

Hospital surveillance of acute stroke treatment in Michigan.

INTRODUCTION: Modern management of acute stroke, including the use of tissue plasminogen activator (t-PA), requires hospitals to be better prepared for rapid diagnosis and treatment. METHODS: Surveillance of practice of acute stroke treatment by Michigan hospitals was performed in 1998. We determined variation in hospital preparedness for treatment by number of emergency department visits. Factors associated with hospital use of t-PA were analyzed using logistic regression. RESULTS: Surveys were returned by 97 (55%) hospitals. Hospitals with a greater number of emergency department visits were significantly more likely to have a clinical pathway, to have given t-PA, and to be better prepared for stroke treatment. After multivariate analysis, greater number of stroke patients per year (P < .001) and availability of skilled intensive care department staff (P = .056) were associated with hospital t-PA use. CONCLUSIONS: Specific hospital characteristics are associated with t-PA use. Consideration of these may be used to devise new strategies for improved delivery of acute stroke treatment.

Synergistic effects of the MTHFR C677T polymorphism and hypertension on spatial navigation.

Navigation skills deteriorate with age, but the mechanisms of the decline are poorly understood. Part of the decrement may be due to age-related vascular risk factors. The T allele in a C677T variant in methylenetetrahydrofolate reductase (MTHFR) gene is associated with elevated plasma homocysteine, which is detrimental to vascular integrity and has been linked to cognitive decline. We inquired if a combination of physiological (hypertension) and genetic (MTHFR 677T) vascular risks has a synergistic negative impact on cognitive performance in otherwise healthy adults. We tested 160 participants (18-80 years old) on a virtual water maze. Advanced age, female sex, and hypertension were associated with poorer performance. However, hypertensive carriers of the T allele performed significantly worse than the rest of the participants at all ages. These findings indicate that hypertension combined with a genetic vascular risk factor may significantly increase risk for cognitive impairment.

Brain-derived neurotrophic factor Val66Met and blood glucose: a synergistic effect on memory.

Age-related declines in episodic memory performance are frequently reported, but their mechanisms remain poorly understood. Although several genetic variants and vascular risk factors have been linked to mnemonic performance in general and age differences therein, it is unknown whether and how they modify age-related memory declines. To address that question, we investigated the effect of Brain-Derived Neurotrophic Factor (BDNF) Val66Met polymorphism that affects secretion of BDNF, and fasting blood glucose level (a vascular risk factor) on episodic memory in a sample of healthy volunteers (age 19-77). We found that advanced age and high-normal blood glucose levels were associated with reduced recognition memory for name-face associations and poorer prose recall. However, elevated blood glucose predicted lower memory scores only in carriers of the BDNF 66Met allele. The effect on associative memory was stronger than on free recall. These findings indicate that even low-level vascular risk can produce negative cognitive effects in genetically susceptible individuals. Alleviation of treatable vascular risks in such persons may have a positive effect on age-related cognitive declines.

Detection of carotid stenosis in African Americans with ischemic heart disease.

OBJECTIVES: This study was conducted to define the frequency of internal carotid stenosis in African American patients with ischemic heart disease (IHD). METHODS: We recruited 101 African American patients with IHD from a university medical center for carotid duplex examination. RESULTS: The frequency of >30%, >50%, and >70% stenosis was 21%, 11%, and 5%, respectively. Age >60 years (21% vs 3%, P < .01) and diabetes mellitus (22% vs 5%, P < .01) were predictors of unilateral stenosis of >50% and remained significant on multivariate testing. CONCLUSION: African American patients with established IHD have higher rates of extracranial carotid stenosis than community dwelling African American subjects and comparable rates with other populations.