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Biomedical subjects

Graeme J Hankey

Publications and source records attributed to Graeme J Hankey.

At least 55 records · Page 3Linked to original sources
PubMed2004

Ongoing and planned trials of antiplatelet therapy in the acute and long-term management of patients with ischaemic brain syndromes: setting a new standard of care.

Among high vascular risk patients, acetylsalicylic acid (ASA) reduces the relative risk of serious vascular events by about one fifth. However, because ASA fails to prevent four fifths of serious vascular events, more effective, yet equally safe and affordable, antiplatelet regimens are desired. Compared with ASA, clopidogrel alone reduces the odds of serious vascular events by about 10%, and the combination of dipyridamole and ASA reduces the odds of serious vascular events by about 6%. Combining ASA with an orally administered platelet glycoprotein (GP) IIb/IIIa blocker is not effective, and indeed more hazardous than ASA alone. Among patients with non-ST-segment acute coronary syndromes (ACS), the addition of an intravenously administered GP IIb/IIIa receptor antagonist to ASA reduces the risk of vascular events by about 10% compared with ASA, and the addition of clopidogrel to ASA reduces the risk of vascular events by 20% compared with ASA alone. Among patients undergoing percutaneous coronary intervention (PCI), both the addition of an intravenously administered GP IIb/IIIa receptor antagonist to ASA, and the addition of clopidogrel to ASA reduce the risk of vascular events by 30% compared with ASA alone. The greater efficacy of the combinations of ASA with clopidogrel, and ASA with an intravenously administered GP IIb/IIIa receptor antagonist, in patients with ACS and those undergoing PCI has fostered several ongoing and planned trials of these regimens in the acute and long-term management of patients with ischaemic brain syndromes. The combination of ASA and clopidogrel is being compared with ASA alone within 12 h of onset of symptoms of TIA in two trials (FASTER, ATARI), and the use of an intravenously administered GP IIb/IIIa receptor antagonist is being compared with placebo within 6 h of onset of acute ischaemic stroke in two trials (AbESST, AbESST-2). Six trials are assessing the combination of clopidogrel and ASA in the long-term management of patients with ischaemic brain syndromes due to atherothrombosis (MATCH, CHARISMA, ARCH, CARESS, SPS3) or atrial fibrillation (ACTIVE). The MATCH trial of clopidogrel and ASA versus clopidogrel alone in patients with recent TIA or ischaemic stroke is the first which is likely to report its results - in mid 2004. The combination of dipyridamole and ASA is being compared with ASA in the ESPRIT trial and with the combination of clopidogrel and ASA in the planned PRoFESS trial. These ongoing and planned clinical trials of antiplatelet therapy promise to further define the role of combination antiplatelet therapy in the acute and long-term management of patients with ischaemic brain syndromes.

Aspirin↗
PubMed2004

Prevention of coronary heart disease with aspirin and clopidogrel: efficacy, safety, costs and cost-effectiveness.

Atherothrombotic coronary artery disease is the single most common cause of death worldwide and a growing public health problem. Platelets play a central role in the pathogenesis of atherothrombosis and are therefore commonly targeted by one or more antiplatelet drugs as part of primary and secondary atherothrombosis prevention strategies. Aspirin reduces the risk of serious vascular events (myocardial infarction, stroke or cardiovascular death) by approximately 20% in a broad range of high-risk patients and remains the first-line antiplatelet drug because of its relative safety, low cost and cost-effectiveness. Compared with aspirin alone, clopidogrel reduces the risk of serious vascular events by approximately 10% and the combination of aspirin and clopidogrel reduces the risk by approximately 20% in patients with non-ST-segment elevation acute coronary syndrome. Clopidogrel has a similar safety profile to aspirin but clopidogrel tablets are substantially more expensive. However, the incremental cost-effectiveness ratio of clopidogrel compared with aspirin is favourable, particularly in high-risk patients and is intermediate compared with a range of other effective therapeutic strategies for the treatment of coronary heart disease. Clopidogrel should be considered as a replacement for aspirin in patients who are allergic to aspirin, cannot tolerate aspirin, have experienced a recurrent atherothrombotic vascular event whilst taking aspirin and are at very high absolute risk of a serious vascular event (e.g., > 20%/year). The combination of clopidogrel and aspirin should be considered in patients with non-ST-segment elevation acute coronary syndrome or undergoing percutaneous coronary intervention.

Aspirin↗
PubMed2004

Failure of aspirin to prevent atherothrombosis: potential mechanisms and implications for clinical practice.

Aspirin (acetylsalicylic acid) reduces the odds of serious atherothrombotic vascular events and death in a broad category of high risk patients by about one-quarter. The mechanism is believed to be inhibition of thromboxane biosynthesis by inactivation of platelet cyclo-oxygenase-1 enzyme. However, aspirin is not that effective; it still fails to prevent the majority of serious vascular events. Mechanisms that may account for the failure of aspirin to prevent vascular events include non-atherothrombotic causes of vascular disease, non-adherence to aspirin therapy, an inadequate dosage, alternative "upstream" pathways of platelet activation (e.g. via stimulation of the ADP, collagen or thrombin receptors on platelets), aspirin-insensitive thromboxane biosynthesis (e.g. via monocyte cyclo-oxygenase-2), or drugs that interfere with the antiplatelet effects of aspirin. Genetic or acquired factors may further modify the inhibitory effects of aspirin on platelets (e.g. polymorphisms involving platelet-associated proteins, increased platelet turnover states). Identification and treatment of the potential causes of aspirin failure could prevent at least another 20% of serious vascular events (i.e. over and above those that are currently prevented by aspirin). There is currently no role for routine laboratory testing to measure the antiplatelet effects of aspirin. Clinicians should ensure that patients at high risk of atherothrombosis (>3% risk over 5 years) are compliant with aspirin therapy and are taking the correct dosage (75-150 mg/day). Patients who cannot tolerate aspirin, are allergic to aspirin, or have experienced recurrent serious atherothrombotic events whilst taking aspirin, should be treated with clopidogrel, and patients with acute coronary syndromes benefit from the combination of clopidogrel plus aspirin. Future research is required to standardize and validate laboratory testing of the antiplatelet effects of aspirin and to identify treatments that can both improve these laboratory measures and reduce the risk of future atherothrombotic events.

Aspirin↗
PubMed2004

Thromboprophylaxis practice patterns in two Western Australian teaching hospitals.

BACKGROUND AND OBJECTIVES: Evidence-based international guidelines recommend that all patients undergoing elective hip or knee arthroplasty receive thromboprophylaxis with low-molecular-weight heparin or adjusted-dose warfarin. Our objective was to determine what proportion of patients undergoing elective hip or knee arthroplasty actually receive recommended thromboprophylaxis according to international guidelines. DESIGN AND METHODS: We performed a prospective cohort study of 396 consecutive patients undergoing elective hip or knee arthroplasty between 1 May and 30 October, 2002. We collected baseline data, surgical and anesthetic details and recorded use of thromboprophylaxis and episodes of venous thromboembolism that occurred within 3 months of surgery. RESULTS: The mean age of the patients was 69.4 years (SD 11.5 years), and 62.2% (95% CI: 57.3 to 66.9%) were female. Hip arthroplasty was performed in 39.4% (34.6 to 44.2%) and knee arthroplasty in 57.1% (52.2 to 61.9%). Recommended thromboprophylaxis with low-molecular-weight heparin or warfarin was administered to 51.5% (46.6 to 56.4%). Objectively diagnosed venous thromboembolism occurred in 5.3% (3.3 to 8.0%) of patients; 3.5% (1.9 to 5.9%) of events occurred during hospitalization and 1.8% (0.7 to 3.6%) occurred following discharge from hospital. There was no significant reduction in the incidence of venous thromboembolism among patients treated with recommended thromboprophylaxis compared with those who did not but this is not a randomized comparison and is potentially confounded by the indication for treatment. INTERPRETATION AND CONCLUSIONS: Current thromboprophylaxis practice at our institutions falls substantially short of national and international guidelines. The reasons for low thromboprophylaxis use should be further explored and strategies for change implemented in order to optimize clinical practice.

Aged↗
PubMed2003

Cyclooxygenase-2 inhibitors: are they really atherothrombotic, and if not, why not?

UNLABELLED: BACKGROUND AND SUMMARY: Selective cyclooxygenase (COX)-2 inhibitors are increasingly being used in place of "conventional" nonsteroidal anti-inflammatory drugs (NSAIDs). This is because they are just as effective as NSAIDs in relieving arthritic pain and yet less gastrotoxic. However, the cardiovascular safety of selective COX-2 inhibitors has been questioned because they selectively reduce prostacyclin production, thus disrupting the normal homeostatic balance and promoting a prothrombotic state. These theoretical concerns appear to be supported by the results of clinical trials demonstrating an increased risk of myocardial infarction with COX-2 inhibitors compared with a conventional NSAID, and indirect comparisons of the rates of myocardial infarction among patients treated with a selective COX-2 inhibitor compared with aspirin in different trials. However, emerging data from animal, experimental and clinical studies suggest that COX-2 is atherogenic and thrombogenic, and that selective COX-2 inhibitors may be cardioprotective. Meta-analyses of randomized trials of selective COX-2 inhibitors compared with placebo have demonstrated no excess of cardiovascular events among patients allocated COX-2 inhibitors, and preliminary data from a randomized controlled trial of the selective COX-2 inhibitor meloxicam, in patients with acute coronary syndrome who were treated with aspirin, demonstrated a reduction in cardiovascular events among patients allocated the COX-2 inhibitor. CONCLUSIONS: Continuing uncertainty regarding the direction and magnitude of any cardiovascular effects of selective COX-2 inhibitors, coupled with their widespread and increasing use, mandates prospective randomized evaluation of their efficacy and safety in patients at increased risk of future cardiovascular events.

Animals↗
PubMed2003

Protein Z in ischemic stroke and its etiologic subtypes.

BACKGROUND AND PURPOSE: Protein Z is a vitamin K-dependent plasma protein whose significance in arterial thrombosis remains uncertain. The objectives of this study were to determine the association between protein Z, ischemic stroke, and etiologic subtypes of ischemic stroke. METHODS: We conducted a case-control study of 173 hospital cases of first-ever ischemic stroke and 186 randomly selected community controls. Using established criteria, we classified cases of stroke by etiologic subtype. Protein Z concentrations were measured during the first 7 days and at 3 to 6 months after the acute stroke event. RESULTS: Blood levels of protein Z measured within 7 days of acute stroke were significantly higher in cases than in controls (geometric mean, 1.46 versus 1.16 microg/mL; P<0.0001). Compared with the lowest tertile, the upper 2 tertiles of protein Z were associated with an adjusted odds ratio (OR) of ischemic stroke of 1.75 (95% CI, 1.00 to 3.07) for the second tertile and 3.07 (95% CI, 1.73 to 5.45) for the upper tertile. The adjusted odds of ischemic stroke caused by large-artery atherothrombosis was nearly 8-fold greater for those with protein Z concentrations in the upper tertile compared with the lower tertile (OR, 7.91; 95% CI, 3.11 to 20.14). The adjusted odds of ischemic stroke due to small-artery disease (OR, 1.79; 95% CI, 0.83 to 3.87) and cardioembolism (OR, 1.80; 95% CI, 0.58 to 5.64) was also increased among individuals with protein Z concentrations in the upper tertile compared with the lower tertile, but not significantly so. There was no significant difference between mean protein Z concentrations among cases in the convalescent phase (3 months) after stroke and age- and sex-matched controls. CONCLUSIONS: There is a strong, independent relationship between elevated blood levels of protein Z and ischemic stroke during the acute phase, particularly ischemic stroke due to large-artery atherothromboembolism, which is no longer evident during the convalescent phase. These results are consistent with the notion that protein Z is either an important factor in the pathogenesis of ischemic stroke due to large-artery atherothromboembolism or an acute phase reactant. Further studies are required to elucidate whether protein Z has a causative or prognostic role in acute arterial thrombosis.

Age Distribution↗
PubMed2003

Endothelial and platelet activation in acute ischemic stroke and its etiological subtypes.

BACKGROUND AND PURPOSE: Activation of endothelial cells and platelets is an important mediator of atherothrombosis. Markers of endothelial cell and platelet activation such as soluble adhesion molecules can be measured in plasma. We hypothesized that patients with acute ischemic stroke would have increased blood concentrations of soluble E-selectin and von Willebrand factor (vWF), primarily reflecting activation of endothelial cells, and increased concentrations of soluble P-selectin and platelet-derived microvesicles (PDM), primarily reflecting activation of platelets, compared with healthy controls. We also hypothesized that these markers would be differentially elevated in ischemic stroke caused by large- and small-artery atherothrombosis compared with cardiogenic embolism. METHODS: We conducted a case-control study of 200 hospital-referred cases of first-ever ischemic stroke and 205 randomly selected community controls stratified by age, sex, and postal code. Using established criteria, we classified cases of stroke by etiological subtype in a blinded fashion. The prevalence of vascular risk factors and blood concentrations of E-selectin, P-selectin, vWF antigen, and PDM were determined in stroke cases within 7 days and at 3 to 6 months after stroke and in controls. RESULTS: Mean blood concentrations of soluble E-selectin, P-selectin, and PDM within 7 days of stroke onset were all significantly higher in cases compared with controls. At 3 to 6 months after stroke, the mean blood concentrations of E-selectin and P-selectin fell significantly below that of controls, and PDM concentrations remained elevated. There was a strong, graded, and independent (of age, sex, and vascular risk factors) association between increasing blood concentrations of E-selectin during the acute phase and all etiological subtypes of ischemic stroke, particularly ischemic stroke caused by large-artery atherothrombosis. There was also a significant, graded, and independent association between increasing blood concentrations of vWF during the acute phase and ischemic stroke caused by large-artery atherothrombosis. CONCLUSIONS: We have demonstrated significant associations between acute elevation of blood markers of endothelial cell and platelet activation and ischemic stroke and between acute elevation of blood markers of endothelial cell activation and ischemic stroke caused by large-artery atherothrombosis. Persistent elevated blood concentrations of PDM may be a marker of increased risk of ischemic stroke.

Acute Disease↗
PubMed2003

Ten-year survival after first-ever stroke in the perth community stroke study.

BACKGROUND AND PURPOSE: Very few studies have provided information regarding long-term prognosis after stroke. We aimed to determine the absolute and relative survival over 10 years among patients with first-ever stroke from a population-based study in Perth, Western Australia. METHODS: For a 12-month period beginning February 1989, all individuals with a suspected acute stroke or transient ischemic attack who were resident in a geographically defined and representative region of Perth, Western Australia, were registered prospectively and assessed according to standardized diagnostic criteria. Patients with a definite first-ever stroke were followed up prospectively at 4 months, 12 months, 5 years, and 10 years after the index event. RESULTS: A total of 251 patients with first-ever stroke were registered, and 244 (97%) were followed up at 10 years, by which time 197 (79%; 95% confidence interval [CI], 74 to 84) had died. The major causes of death were the direct effects of the initial stroke (27%; 95% CI, 21 to 33) and cardiovascular disease (26%; 95% CI, 20 to 32). Among 1-year survivors of stroke, the average annual case fatality was 4.8%, which was 2.3 (95% CI, 1.9 to 2.7) times greater than for the general population of the same age and sex. CONCLUSIONS: One in 5 patients with first-ever stroke survived to 10 years. The average annual case fatality was 4.8% between years 1 and 10 after stroke, which was twice that expected for the general population. Vascular disease is the major cause of death among long-term survivors of stroke.

Adult↗
PubMed2003

Design of future acute-stroke treatment trials.

Very few trials of acute stroke treatments show efficacy of a tested agent on the prespecified primary outcome. We can learn many lessons from the studies that achieve only neutral results. Preclinical studies have been flawed by use of models of transient not permanent brain ischaemia, treatments that aim to protect cerebral grey matter independently of white matter, delivery of the study drug within too short a time window after ischaemic insult, use of surrogate outcome measures in the short term instead of function in the long-term, and small sample sizes. Clinical trials have been hampered by heterogeneity in causes of stroke and inability to classify subtypes of cause; the short time available to rescue ischaemic brain tissue; the haemorrhagic transformation that can cause severe functional consequences seen frequently in infarcted brain tissue; the lack of valid, reliable, sensitive, and simple tools for assessment of functional outcome; and, above all, small treatment effects that are difficult to detect or refute. In this review, we look at the designs and results of all controlled trials of treatments for ischaemic stroke, and try to identify opportunities to improve future treatment assessment.

Clinical Trials as Topic↗
PubMed2003

Management of acute ischaemic stroke: new guidelines from the American Stroke Association and European Stroke Initiative.

BACKGROUND: Ischaemic stroke is an important cause of death and dependency in industrialised countries; it has a high incidence (affecting up to 0.2% of the population each year) and is commonly lethal or disabling. One in six patients die in the first month after ischaemic stroke, and half of survivors are permanently disabled despite best efforts to rehabilitate them and to prevent complications, recurrent stroke, and other serious vascular events. Optimisation of the early, and ongoing, management of patients with acute ischaemic stroke is pivotal to the reduction of both case fatality and long-term disability. RECENT DEVELOPMENTS: Guidelines for the early management of patients with ischaemic stroke have recently been published by the Stroke Council of the American Stroke Association (ASA; Adams and co-workers, Stroke 2003; 34: 1056-83) and the European Stroke Initiative (EUSI; European Stroke Initiative Executive Committee and Writing Committee, Cerebrovasc Dis 2003; 16: 311-38). Although transatlantic differences might create different interpretations, priorities, and views, the guidelines are remarkably similar, even regarding controversial issues. We believe this is not only because both groups have had the opportunity to discuss many of the controversial issues at international meetings, but also because both groups have endorsed the concept of evidence-based medicine and have based their recommendations on similar classifications of the levels of evidence for the effectiveness of interventions. This is a triumph for evidence-based medicine and a major step towards unification of acute stroke management worldwide. WHERE NEXT?: There are three main challenges in stroke management. To increase the body of reliable evidence from large randomised controlled trials (RCTs) of the safety, effectiveness, and cost of promising treatments (eg, thrombolysis, antithrombotic therapy, neuroprotection, and interventional recanalisation, alone and in combination) in a wide range of patients around the world. To facilitate the widespread development of stroke units, delivery of organised stroke care, and emergency transport of patients with stroke to appropriate stroke centres. And finally, to improve the uptake of effective therapies into clinical practice (eg, by widely disseminating the ASA and EUSI guidelines).

Acute Disease↗
PubMed2003

Long-term outcome after ischaemic stroke/transient ischaemic attack.

During the first 30 days after a stroke, the case fatality is about 25% and the major cause of death is the index stroke and its sequelae. The most consistent predictor of 30-day mortality after stroke is stroke severity. Other predictors include increasing age, a history of previous stroke, cardiac failure, and a high blood glucose concentration and white blood cell count. Other less common, but important, causes of early mortality are recurrent ischaemic stroke and a coronary event. The risk of a recurrent cerebrovascular event is highest in the first month (4%) and year (12%) after a stroke and transient ischaemic attack (TIA), probably reflecting the presence of active, unstable atherosclerotic plaque. Thereafter, the risk of a recurrent cerebrovascular event falls to about 5% per year, similar to the risk of a coronary event. During years 1-5 after a TIA and ischaemic stroke, cardiovascular disease increasingly becomes the major cause of death, reflecting the generalized nature of atherothrombosis, the most common cause of the index stroke. The most robust predictor of death within 1-5 years after stroke is increasing age, closely followed by cardiac failure. Additional baseline predictors of longer-term mortality include a history of previous symptomatic atherothrombosis (TIA, ischaemic stroke, peripheral arterial disease, and early-onset ischaemic heart disease), risk factors for atherothrombosis (smoking), other heart diseases (cardiac failure, atrial fibrillation) and increasing stroke severity. Lacunar syndromes can be predictive of relative longevity. At 5 years after stroke, survival is about 40%, and about half of survivors are disabled and dependent. The most robust predictors of disability at 5 years after stroke are increasing age, stroke severity, and recurrent stroke. The most powerful predictor of early recurrent stroke (within 30 days after stroke) is an atherosclerotic ischaemic stroke caused by large-artery atherosclerosis with >50% stenosis, whereas the strongest predictor of stroke recurrence over 5 years is diabetes. Other predictors of recurrent stroke include increasing age, previous TIA, atrial fibrillation, high alcohol consumption, haemorrhagic index stroke, and hypertension at discharge. The clinical implication of these findings is that strategies for optimizing long-term outcome after TIA and stroke should be directed toward reducing the high risk of recurrent stroke and coronary events by removing/recanalizing the symptomatic atherosclerotic plaque, controlling the underlying causal vascular risk factors, and administering long-term, effective antiplatelet therapy.

Cardiovascular Diseases↗