The Greater Cincinnati/Northern Kentucky Stroke Study: preliminary first-ever and total incidence rates of stroke among blacks

Stroke risk factors

Despite advances in the treatment of acute cerebral infarction, the most effective method of reducing stroke morbidity and mortality is the identification and modification of stroke risk factors. Modifiable stroke risk factors include hypertension, atrial fibrillation, hypercholesterolemia, cigarette smoking, hyperhomocystinemia, and carotid stenosis. Improved identification of individuals at increased stroke risk due to these factors can reduce individual risk and the cost to society of the consequences of stroke.

Potential future clinical applications for the GPIIb/IIIa antagonist, abciximab in thrombosis, vascular and oncological indications

Abciximab (ReoPro) is a mouse-human chimeric monoclonal antibody Fab fragment of the parent murine monoclonal antibody 7E3, and was the first of these agents approved for use as adjunct therapy for the prevention of cardiac ischemic complications in patients undergoing percutaneous coronary intervention (PCI). Abciximab binds with high avidity to both the non-activated and activated form of the GPIIb/IIIa receptor of platelets, the major adhesion receptor involved in aggregation. Additional cardiovascular indications for abciximab are unstable angina, carotid stenting, ischemic stroke and peripheral vascular diseases. Abciximab also interacts with two other integrin receptors; the a av b b3 receptor, which is present in low numbers on platelets but in high density on activated endothelial and smooth muscle cells, and a aMb b2 integrin which is present on activated leukocytes. Cell types that express integrins GPIIb/IIIa and a av b b3 such as platelets, endothelial and tumor cells have been implicated in angiogenesis, tumor growth and metastasis. Since abciximab interacts with high avidity to integrins GPIIb/IIIa and a av b b3, it is reasonable to assume that it may possess anti-angiogenic properties in angiogenesis-related diseases, as well as anti-metastastatic properties in case of disseminating tumors expressing the target integrin receptors.

Is carotid endarterectomy cost-effective in symptomatic patients with moderate (50% to 69%) stenosis?

OBJECTIVE

Recently published data from the North American Carotid Endarterectomy Trial revealed a benefit for carotid endarterectomy (CEA) in symptomatic patients with moderate (50% to 69%) carotid stenosis. This benefit was significant but small (absolute stroke risk reduction at 5 years, 6.5%; 22.2% vs 15.7%), and thus, the authors of this study were tentative in the recommendation of operation for these patients. To better elucidate whether CEA in symptomatic patients with moderate carotid stenosis is a proper allocation of societal resources, we examined the cost-effectiveness of this intervention.

METHODS

A decision-analytic Markov process model was constructed to determine the cost-effectiveness of CEA versus medical treatment for a hypothetical cohort of 66-year-old patients with moderate carotid stenosis. This model allowed the comparison of not only the immediate hospitalization but also the lifetime costs and benefits of these two strategies. Our measure of outcome was the cost-effectiveness ratio (CER), defined as the incremental lifetime cost per quality-adjusted life year saved. We assumed an operative stroke and death rate of 6.6% and a declining risk of ipsilateral stroke after the ischemic event with medical treatment (first year, 9.3%; second year, 4%; subsequent years, 3%). The hospitalization cost of CEA ($6,420) and the annual costs of major stroke ($26,880), minor stroke ($798), and aspirin therapy ($63) were estimated from a hospital cost accounting system and the literature.

RESULTS

CEA for moderate carotid stenosis increased the survival rate by 0.13 quality-adjusted life years as compared with medical treatment at an additional lifetime cost of $580. Thus, CEA was cost-effective with a CER of $4,462. Society is usually willing to pay for interventions with CERs of less than $60,000 (eg, CERs for coronary artery bypass grafting at $9,100 and for dialysis at $53,000). CEA was not cost-effective if the perioperative risk was greater than 11.3%, if the ipsilateral stroke rate associated with medical treatment at 1 year was reduced to 4.3%, if the age of the patient exceeded 83 years, or if the cost of CEA exceeded $13,200.

CONCLUSION

CEA in patients with symptomatic moderate carotid stenosis of 50% to 69% is cost-effective. Perioperative risk of stroke or death, medical and surgical stroke risk, cost of CEA, and age are important determinants of the cost-effectiveness of this intervention.

Intravenous thrombolytic therapy for stroke: a review of recent studies and controversies

STUDY OBJECTIVES

To review the randomized, controlled, multicenter trials of intravenous thrombolytic therapy for ischemic stroke.

METHODS

Studies of ischemic stroke confirmed by computed tomography (CT) and randomization of more than 100 patients are reviewed. Streptokinase studies are the MAST-I, the MAST-E, and the ASK Trial. Studies using tissue plasminogen activator (tPA) are the NINDS Stroke Study, ECASS I, ECASS II, and ATLANTIS. One study using ancrod is STAT. We discuss significant factors common to each study, including thrombolytic agent used, CT scan interpretation, time of therapy administration in relation to stroke onset, thrombolytic dose, ancillary medication administration, safety, and neurologic outcomes.

RESULTS

All streptokinase studies were stopped early because of increased mortality in the treated groups. Initial results of the STAT study are promising; publication of full study details is awaited. The ATLANTIS study was terminated early because of nonstatistical efficacy at interim analysis. The NINDS and the ECASS trials were completed; only the NINDS study demonstrated significant increase in the percentage of patients with complete recovery or minimal deficit at 3 months, without significant difference in mortality in the treated group.

CONCLUSION

This review supports the use of intravenous thrombolytic therapy for ischemic stroke using tPA at a dose of.9 mg/kg body weight and a "golden window" treatment time of 3 hours. Administration without strict adherence to protocol, even within this time frame, may shift the benefit/risk profile of tPA. We recommend the treating physician have rapid access to CT scanning and to collaboration with individuals experienced in the evaluation of stroke and CT interpretation.

1999 World Health Organization-International Society of Hypertension Guidelines for the management of hypertension. Guidelines sub-committee of the World Health Organization

The present Guidelines were prepared by the Guidelines Sub-Committee of the World Health Organization-International Society of Hypertension (WHO-ISH) Mild Hypertension Liaison Committee, the members of which are listed at the end of the text. These guidelines represent the fourth revision of the WHO-ISH Guidelines and were finalised after presentation and discussion at the 7th WHO-ISH Meeting on Hypertension, Fukuoka, Japan, 29th Sept-1st Oct, 1998. Previous versions of the Guidelines were published in Bull WHO 1993, 71:503-517 and J Hypertens 1993, 11:905-918.

A nationwide prehospital stroke survey

OBJECTIVES

To identify deficiencies in stroke knowledge among prehospital providers.

METHODS

A nationwide multiple-choice survey was sent to 689 paramedics (EMT-Ps) and 294 advanced EMTs (EMT-Is) from a random selection of the National Registry of Emergency Medical Technicians database. Of the 23 questions, five addressed demographic information, four quantity of training, five general knowledge, 6 and seven management, and two open-ended questions addressed the signs, symptoms, and risk factors of stroke. The EMT-P and EMT-I answers were compared using chi-square analysis or Fisher's exact test.

RESULTS

Of the 355 (36%) respondents, 256 (72%) were EMT-Ps and 99 (28%) were EMT-Is. Virtually all the EMT-Ps (99%) and EMT-Is (98%) knew that a stroke injures the brain, but only 199 (78%) of the EMT-Ps and 47 (47%) of the EMT-Is correctly defined a transient ischemic attack (TIA) (p < 0.001). Slurred speech, weakness/ paralysis, and altered mental status were the three most commonly cited symptoms of stroke by both groups. The EMT-Ps were more likely to recognize that dextrose is potentially harmful to stroke patients [EMT-P = 216 (85%), EMT-I = 71 (72%), p = 0.005]; 169 (66%) of the EMT-Ps and 75 (76%) of the EMT-Is felt that elevated blood pressures should be lowered in the prehospital setting. Only 93 (36%) of the EMT-Ps and 22 (22%) of the EMT-Is knew that tissue plasminogen activator (tPA) must be given within three hours of symptom onset (p = 0.01).

CONCLUSION

Most EMS providers are knowledgeable about the symptoms of stroke but are unaware of the therapeutic window for thrombolysis and the recommended avoidance of prehospital blood pressure reduction. In addition, further education is needed regarding TIAs.

Racial differences in the incidence of intracerebral hemorrhage: effects of blood pressure and education

OBJECTIVE

To determine the relative risk (RR) of intracerebral hemorrhage (ICH) among African Americans compared with that among whites.

METHODS

Data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study were used to determine the incidence of ICH (n = 78) in 10,851 whites and 1,802 African Americans during a 20-year follow-up period. Cox proportional hazards analyses were used to determine the RR of ICH among African Americans compared with that among whites.

RESULTS

The estimated annual incidence of ICH was 50 per 100,000 among African Americans and 28 per 100,000 among whites. The age- and sex-adjusted RR for ICH among African Americans was 1.9 (95% confidence interval [CI], 1.1 to 3.2). With the addition of systolic blood pressure and educational attainment to the Cox proportional hazards model, the RR decreased to 1.6 (95% CI, 0.9 to 2.7). The adjustment for additional cerebrovascular disease risk factors did not change this risk estimate appreciably.

CONCLUSIONS

Compared with whites, African Americans have a twofold increased risk for ICH. Most of this risk may be explained by differences in educational attainment and systolic blood pressure. Unless additional efforts are undertaken to reduce racial differences in the prevalence of stroke risk factors, mainly systolic blood pressure and socioeconomic status, the African American-white disparities in the risk for ICH will likely continue.

Ethnic differences in incidence of stroke: prospective study with stroke register

OBJECTIVE

To identify ethnic differences in the incidence of first ever stroke.

DESIGN

A prospective community stroke register (1995-6) with multiple notification sources. Pathological classification of stroke in all cases was based on brain imaging or necropsy data. Rates were standardised to European and world populations and adjusted for age, sex, and social class in multivariate analysis.

SETTING

A multi-ethnic population of 234 533 in south London, of whom 21% are black.

RESULTS

612 strokes were registered. The crude annual incidence rate was 1.3 strokes per 1000 population per year (95% confidence interval 1.20 to 1.41) and 1.25 per 1000 population per year (1.15 to 1.35) age adjusted to the standard European population. Incidence rates adjusted for age and sex were significantly higher in black compared with white people (P<0.0001), with an incidence rate ratio of 2.21 (1.77 to 2.76). In multivariable analysis increasing age (P<0.0001), male sex (P<0.003), black ethnic group (P<0.0001), and lower social class (P<0.0001) in people aged 35-64 were independently associated with an increased incidence of stroke.

CONCLUSIONS

Incidence rates of stroke are higher in the black population; this is not explained by confounders such as social class, age, and sex. Ethnic differences in genetic, physiological, and behavioural risk factors for stroke require further elucidation to aid development of effective strategies for stroke prevention in multi-ethnic communities.

Diagnosis and treatment of ischemic stroke

Most patients who have a stroke are evaluated initially by a primary care physician. For patients to benefit from new stroke therapies that must be initiated within a few hours of stroke onset, primary care physicians must be prepared to diagnose stroke and initiate acute treatment. This article provides information on the rapid and accurate diagnosis and management of patients with acute ischemic stroke. This information is particularly relevant due to the relatively high risk:benefit ratio associated with some acute stroke therapies, such as tissue plasminogen activator. Information is also provided about medical and surgical therapies to prevent subsequent strokes.

African American antiplatelet stroke prevention study: Clinical trial design

BACKGROUND AND PURPOSE

African Americans are about two times more likely than European Americans to die of cerebrovascular disease or to experience stroke. Although this disparity exists, African Americans have been underrepresented in clinical trials. The African American Antiplatelet Stroke Prevention Study (AAASPS) is a multi-center, randomized, double-blind, clinical trial to compare the effect of ticlopidine and aspirin in the prevention of recurrent stroke, myocardial infarction, and vascular death in African Americans with recent, noncardioembolic ischemic stroke.

TRIAL DESIGN

There will be 1,800 African American noncardioembolic ischemic stroke patients at 40 sites nationally randomized to receive ticlopidine (500 mg/d) or aspirin (650 mg/d) at least 7 days but no more than 90 days after the qualifying event. Complete blood count and platelet count are monitored every 2 weeks during the first 3 months of active treatment to monitor for neutropenia and thrombocytopenia. Patients with transient cerebral ischemia, recent active peptic ulcer disease or lower gastrointestinal bleeding, bleeding diathesis, and women of childbearing potential are excluded. Study patients will be followed-up for a total of 2 years for occurrence of the primary outcome endpoint cluster of recurrent stroke, myocardial infarction, and vascular death. Safety analyses will focus on the incidence of severe adverse events such as neutropenia, thrombocytopenia, gastrointestinal bleeding, and liver dysfunction. Analyses for key endpoints will use the intention-to-treat principle and time-to-event data will be analyzed using Mantel-Haenszel and various regression methods.

CONCLUSION

African Americans have a survival disadvantage that substantially relates to the occurrence of stroke. AAASPS is the first secondary stroke prevention study exclusively for African Americans and promises to provide important information to guide recurrent stroke prevention treatment for this high-risk group.

Multilocus linkage identifies two new loci for a mendelian form of stroke, cerebral cavernous malformation, at 7p15-13 and 3q25.2-27

Cerebral cavernous malformation (CCM) is a Mendelian model of stroke, characterized by focal abnormalities in small intracranial blood vessels leading to hemorrhage and consequent strokes and/or seizures. A significant fraction of cases is inherited as an autosomal dominant trait with incomplete penetrance. Among Hispanic Americans, virtually all CCM is attributable to a founder mutation localized to 7q ( CCM1 ). Recent analysis of non-Hispanic Caucasian kindreds, however, has excluded linkage to 7q in some, indicating at least one additional CCM locus. We now report analysis of linkage in 20 non-Hispanic Caucasian kindreds with familial CCM. In addition to linkage to CCM1, analysis of linkage demonstrates linkage to two new loci, CCM2 at 7p13-15 and CCM3 at 3q25.2-27. Multilocus analysis yields a maximum lod score of 14.11, with 40% of kindreds linked to CCM1, 20% linked to CCM2 and 40% linked to CCM3, with highly significant evidence for linkage to three loci (linkage to three loci supported with an odds ratio of 2.6 x 10(5):1 over linkage to two loci and 1.6 x 10(9):1 over linkage to one locus). Multipoint analysis among families with high posterior probabilities of linkage to each locus refines the locations of CCM2 and CCM3 to approximately 22 cM intervals. Linkage to these three loci can account for inheritance of CCM in all kindreds studied. Significant locus-specific differences in penetrance are identified. These findings have implications for genetic testing of this disorder and represent an important step toward identification of the molecular basis of this disease.

Case presentations of neuroradiologic interventions for acute cerebrovascular disease

The treatment options and management of ischemic and hemorrhagic stroke are expanding. Neuroradiologic interventions are being used in acute care settings to change the course of these devastating processes. These interventions include the injection of intra-arterial urokinase for ischemic stroke, use of coils to secure aneurysms, and balloon angioplasty for increasing the lumen of spastic cerebral arteries in patients with cerebral vasospasm. Using a case study approach, these three options for managing stroke patients will be integrated, and nursing strategies for delivering care to the stroke patient will be profiled.