Rosemary Miller

The Risk of Subarachnoid and Intracerebral Hemorrhages in Blacks as Compared with Whites

BACKGROUND Stroke is an important cause of death among blacks, and intracerebral and subarachnoid hemorrhages account for nearly half of all early deaths from stroke. The present study investigates whether blacks and whites differ in their risk of having either intracerebral or subarachnoid hemorrhage. METHODS We reviewed the medical records, autopsy reports, and CT scans of all patients suspected of having had an intracerebral or subarachnoid hemorrhage during 1988 among the nearly 1.3 million people in the Greater Cincinnati metropolitan area. RESULTS There were 221 cases of first spontaneous intracranial hemorrhage among 1,086,462 whites (159 intracerebral and 62 subarachnoid hemorrhages), and 45 cases among 171,718 blacks (27 intracerebral and 18 subarachnoid hemorrhages). Blacks had 2.1 times the risk of subarachnoid hemorrhage of whites (95 percent confidence interval, 1.3 to 3.6) and 1.4 times the risk of intracerebral hemorrhage (95 percent confidence interval, 0.9 to 2.1). In those under the age of 75, the risk of intracerebral hemorrhage among blacks was 2.3 times that of whites (95 percent confidence interval, 1.5 to 3.6), whereas the risk among blacks 75 or older was one fourth that of whites (95 percent confidence interval, 0.1 to 0.8). Deaths within 30 days of intracerebral or subarachnoid hemorrhage accounted for 1.9 years of life lost per 1000 blacks under 65 years of age, as compared with 0.5 year per 1000 whites. CONCLUSIONS Young and middle-aged blacks have a substantially higher risk of subarachnoid or intracerebral hemorrhage than whites of similar age. These types of stroke are important causes of excess mortality among young and middle-aged blacks.

Stroke in a Biracial Population The Excess Burden of Stroke Among Blacks

Background and Purpose— Excess mortality resulting from stroke is an important reason why blacks have higher age-adjusted mortality rates than whites. This observation has 2 possible explanations: Strokes occur more commonly among blacks or blacks have higher mortality rates after stroke. Our population-based epidemiological study is set in the Greater Cincinnati/Northern Kentucky region of 1.31 million people, which is representative of the US white and black populations with regard to many demographic and socioeconomic characteristics. Methods— Hospitalized cases were ascertained by International Classification of Diseases (ninth revision) discharge codes, prospective screening of emergency department admission logs, and review of coroner’s cases. A sampling scheme was used to ascertain cases in the out-of-hospital setting. All potential cases underwent detailed chart abstraction by study nurses, followed by physician review. Race-specific incidence and case fatality rates were calculated. Results— We identified 3136 strokes during the study period (January 1, 1993, to June 30, 1994). Stroke incidence rates were higher for blacks at every age, with the greatest risk (2- to 5-fold) seen in young and middle-aged blacks (<65 years of age). Case fatality rates did not differ significantly in blacks compared with whites. Applying the resulting age- and race-specific rates to the US population in 2002, we estimate that 705 000 to 740 000 strokes have occurred in the United States, with a minimum of 616 000 cerebral infarctions, 67 000 intracerebral hemorrhages, and 22 000 subarachnoid hemorrhages. Conclusions— Excess stroke-related mortality in blacks is due to higher stroke incidence rates, particularly in the young and middle-aged. This excess burden of stroke incidence among blacks represents one of the most serious public health problems facing the United States.

Eligibility for Recombinant Tissue Plasminogen Activator in Acute Ischemic Stroke: A Population-Based Study

Background and Purpose— Acute ischemic stroke patients are infrequently treated with recombinant tissue plasminogen activator (rtPA). We present unique population-based data regarding the eligibility of ischemic stroke patients for rtPA treatment. Methods— All ischemic strokes presenting to an emergency department (ED) within a biracial population of 1.3 million were identified. The patient was considered eligible for rtPA on the basis of exclusion criteria from the National Institute of Neurological Disorders and Stroke rtPA trial. Results— Of 2308 ischemic strokes, 1849 presented to an ED. Only 22% of all ischemic strokes in the population arrived in the ED in <3 hours from symptom onset; of these, 209 (51%) were ineligible for rtPA on the basis of mild stroke severity, medical and surgical history, or blood tests. Conclusions— In our population in 1993 to 1994, 8% of all ischemic stroke patients presented to an ED within 3 hours and met other eligibility criteria for rtPA. Even if time were not an exclusion for rtPA, only 29% of all ischemic strokes in our population would have otherwise been eligible for rtPA.

Ischemic Stroke Subtypes. A Population-Based Study of Incidence Rates Among Blacks and Whites

Background and Purpose— Blacks have an excess burden of stroke compared with whites; however, data comparing ischemic stroke subtypes among the 2 groups are limited and typically involve relative frequencies. The objective of this study is to compare the incidence rates of ischemic stroke subtypes between blacks and whites within a large, representative, biracial population. Methods— The Greater Cincinnati/Northern Kentucky Stroke Study is designed to measure incidence rates and trends of all strokes within a well-defined, large, biracial population. Hospitalized cases were ascertained by International Classification of Disease (9th revision; ICD-9) discharge codes. Out-of-hospital events were ascertained by prospective screening of emergency department admission logs, review of coroners’ cases, and monitoring all public health and hospital-based primary care clinics. A sampling scheme was used to ascertain events from nursing homes and all other primary care physician offices. All potential cases underwent detailed chart abstraction and confirmed by physician review. Based on all available clinical, laboratory, and radiographic information, ischemic stroke cases were subtyped into the following categories: cardioembolic, large-vessel, small-vessel, other, and stroke of undetermined cause. Race-specific incidence rates were calculated and compared after adjusting for age and gender, and standardizing to the 1990 US population. Results— Between July 1, 1993, and June 30, 1994, 1956 first-ever ischemic strokes occurred among blacks and whites in the study population. Small-vessel strokes and strokes of undetermined cause were nearly twice as common among blacks. Large-vessel strokes were 40% more common among blacks than whites, and there was a trend toward cardioembolic strokes being more common among blacks. Conclusions— The excess burden of ischemic strokes among blacks compared with whites is not uniformly spread across the different subtypes. Large-vessel strokes are more common and cardioembolic stroke are as common among blacks, traditionally thought to be more common among whites.

Incidence of seizures in the acute phase of stroke: A population‐based study

Purpose: The incidence of seizures within 24 h of acute stroke has not been studied extensively. We aimed to establish the incidence of acute poststroke seizures in a biracial cohort and to determine whether acute seizure occurrence differs by race/ethnicity, stroke subtype, and/or stroke localization.

Incidence Rates of First-Ever Ischemic Stroke Subtypes Among Blacks: A Population-Based Study

BACKGROUND AND PURPOSE The aim of this study was to determine the incidence rates of ischemic stroke subtypes among blacks. METHODS Hospitalized and autopsied cases of stroke and transient ischemic attack among the 187 000 blacks in the 5-county region of greater Cincinnati/northern Kentucky From January 1, 1993, through June 30, 1993, were identified. Incidence rates were age- and sex-adjusted to the 1990 US population. Subtype classification was performed after extensive review of all available imaging, laboratory data, clinical information, and past medical history. Case-control comparisons of risk factors were made with age-, race-, and sex-matched control subjects. RESULTS Annual incidence rates per 100 000 for first-ever ischemic stroke subtypes among blacks were as follows: uncertain cause, 103 (95% confidence interval [CI], 80 to 126); cardioembolic, 56 (95% CI, 40 to 73); small-vessel infarct, 52 (95% CI, 36 to 68); large vessel, 17 (95% CI, 8 to 26); and other causes, 17 (95% CI, 9 to 26). Of the patients diagnosed with an infarct of uncertain cause, 31% underwent echocardiography, 45% underwent carotid ultrasound, and 48% had neither. Compared with age-, race-, and sex- (proportionally) matched control subjects from the greater Cincinnati/northern Kentucky region, the attributable risk of hypertension for all causes of first-ever ischemic stroke is 27% (95% CI, 7 to 43); for diabetes, 21% (95% CI, 11 to 29); and for coronary artery disease, 9% (95% CI, 2 to 16). For small-vessel ischemic stroke, the attributable risk of hypertension is 68% (95% CI, 31 to 85; odds ratio [OR], 5.0), and the attributable risk of diabetes is 30% (95% CI, 10 to 45; OR, 4.4). For cardioembolic stroke, the attributable risk of diabetes is 25% (95% CI, 4 to 41; OR, 3.1). CONCLUSIONS Stroke of uncertain cause is the most common subtype of ischemic stroke among blacks. Cardioembolic stroke and small-vessel stroke are the most important, identifiable causes of first-ever ischemic stroke among blacks. The incidence rates of cardioembolic and large-vessel stroke are likely underestimated because noninvasive testing of the carotid arteries and echocardiography were not consistently obtained in stroke patients at the 18 regional hospitals. Most small-vessel strokes in blacks can be attributed to hypertension and diabetes.

Decreased Perihematomal Edema in Thrombolysis-Related Intracerebral Hemorrhage Compared With Spontaneous Intracerebral Hemorrhage

BACKGROUND AND PURPOSE Intracerebral hemorrhage (ICH) is a highly morbid disease process. Perihematomal edema is reported to contribute to clinical deterioration and death. Recent experimental observations indicate that clotting of the intrahematomal blood is the essential prerequisite for hyperacute perihematomal edema formation rather than blood-brain barrier disruption. METHODS We compared a series of patients with spontaneous ICH (SICH) to a series of patients with thrombolysis-related ICH (TICH). All patients were imaged within 3 hours of clinical onset. We reviewed relevant neuroimaging features, emphasizing and quantifying perihematomal edema. We then analyzed clinical and radiological differences between the 2 ICH types and determined whether these factors were associated with perihematomal edema. RESULTS TICHs contained visible perihematomal edema less than half as often as SICHs (31% versus 69%, P<0.001) and had both lower absolute edema volumes (0 cc [25th, 75th percentiles: 0, 6] versus 6 cc [0, 13], P<0.0001) and relative edema volumes (0.16 [0.10, 0.33] versus 0.55 [0.40, 0.83], P<0.0001). Compared with SICHs, TICHs were 3 times larger in volume (median [25th, 75th percentiles] volume 69 cc [30, 106] versus 21 cc [8, 45], P<0.0001), 4 times more frequently lobar in location (62% versus 15%, P<0.001), 80 times more frequently contained blood-fluid level(s) (86% versus 1%, P<0.001), and were more frequently multifocal (22% versus 0%, P<0.001). CONCLUSIONS The striking qualitative and quantitative lack of perihematomal edema observed in the thrombolysis-related ICHs compared with the SICHs provides the first substantial, although indirect, human evidence that intrahematomal blood clotting is a plausible pathogenetic factor in hyperacute perihematomal edema formation.