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Biomedical subjects

G J Hankey

Publications and source records attributed to G J Hankey.

At least 19 recordsLinked to original sources
PubMed1995

Asymptomatic carotid stenosis: how should it be managed?

OBJECTIVE: To discuss the implications of recent studies on carotid endarterectomy for asymptomatic carotid stenosis. DATA SOURCES: Trials of the effectiveness of carotid endarterectomy in asymptomatic carotid stenosis, including the Asymptomatic Carotid Atherosclerosis Study (ACAS). RESULTS: In the ACAS study, carotid endarterectomy for asymptomatic moderate to severe carotid stenosis (60%-99% luminal obstruction) reduced the absolute risk of ipsilateral stroke or death at five years by 5.9%. This means that about 17 patients need to be operated on to prevent one stroke or death over five years. To operate on all Australians with asymptomatic 60%-99% carotid stenosis would cost an estimated $A1.24 billion and prevent 800 strokes per year, or only 3% of all first strokes in Australia. RECOMMENDATIONS: In order to identify who will benefit from carotid endarterectomy and who will remain symptom-free without it, patients should continue to be allocated to the ongoing Asymptomatic Carotid Surgery Trail. Otherwise, carotid endarterectomy should be reserved for patients at high risk of stroke (i.e., with 95%-99% carotid stenosis) who are medically fit for surgery and willing to take the small short term risk of surgery for a possible greater long term benefit.

Adult↗
PubMed1995

Transient ischaemic attacks.

Each day, about 25 Australians experience a transient ischaemic attack of the brain or eye. These people need to be distinguished from those who suffer "funny turns" due to other causes because, as a group, they have a significant risk of stroke and other vascular events. This risk can be substantially reduced through control of vascular risk factors, use of long term antithrombotic medication and, in some cases, carotid endarterectomy. Strategies for stroke prevention need to involve both the "high risk" and population "mass" approach, which are complementary.

Anticoagulants↗
PubMed1994

Mechanism of stroke complicating cardiopulmonary bypass surgery.

BACKGROUND: Stroke is a devastating complication of cardiopulmonary bypass (CPB) surgery which occurs in 1 to 5% of cases. Strategies to reduce its incidence require a knowledge of the underlying pathology and aetiology. AIMS: To determine the incidence, pathology and aetiology of stroke complicating CPB. METHODS: Prospective review of clinical, operative and cranial CT scan findings in all cases of stroke complicating CPB procedures in our institution over an 18 month period. RESULTS: Twenty-one (1.6%, 95% CI 0.9-2.3%) cases of stroke were identified from 1336 CPB procedures. Cranial CT scan, performed in all but one patient, was normal in three patients or consistent with ischaemic stroke in 17 patients. There were no cases of haemorrhagic infarction or intracerebral haemorrhage. It was difficult to differentiate embolic and borderzone infarcts in two cases. After considering the clinical, operative and CT scan features together, 12 (57%, 95% CI 36-78%) of the cases were felt to be embolic in origin and nine (43%, 95% CI 22-64%) due to hypoperfusion in a borderzone. CONCLUSIONS: This study demonstrates that stroke remains an important complication of CPB procedures with an incidence in our series of 1.6%. The pathologic type of stroke is predominantly ischaemic in nature due to either cerebral embolism or borderzone infarction. Strategies for stroke prevention in patients undergoing CPB should be targeted primarily at these two mechanisms.

Adult↗
PubMed1994

Validation of a clinical classification for subtypes of acute cerebral infarction.

The validity of a clinical classification system was assessed for subtypes of cerebral infarction for use in clinical trials of putative stroke therapies and clinical decision making in a population based stroke register (n = 536) compiled in Perth, Western Australia in 1989-90. The Perth Community Stroke Project (PCSS) used definitions and methodology similar to the Oxfordshire Community Stroke Project (OCSP) where the classification system was developed. In the PCSS, 421 cases of cerebral infarction and primary intracerebral haemorrhage (PICH), confirmed by brain imaging or necropsy, were classified into the subtypes total anterior circulation syndrome (TACS), partial anterior circulation syndrome (PACS), lacunar syndrome (LACS), and posterior circulation syndrome (POCS). In this relatively unselected population, relying exclusively on LACS for a diagnosis of PICH had a very low sensitivity (6%) and positive predictive value (3%). Comparison of the frequencies and outcomes (at one year after the onset of symptoms) for each subgroup of first ever cerebral infarction in the PCSS (n = 248) with the OCSP (n = 543) registers showed uniformity only for LACI. For example, there were 27% of cases of TACI in the PCSS compared with 17% in the OCSP (difference = 10%; 95% confidence interval (95% CI) 4% to 16%) and 15% of cases in the PCSS compared with 24% in the OCSP were POCI (difference = 9%; 95% CI 3% to 15%). Case fatalities and long-term handicap across the subgroups were not significantly different between studies, but the frequencies of recurrent stroke were significantly greater for POCI in the OCSP compared with the PCSS. Although this classification system defines subtypes of stroke with different outcomes, simple clinical measures-level of consciousness, paresis, disability, and incontinence at onset-are more powerful predictors of death or dependency at one year. It is concluded that simple clinical measures that reflect the severity of the neurological deficit should complement this classification system in clinical trials and practice.

Acute Disease↗
PubMed1993

Can the long term outcome of individual patients with transient ischaemic attacks be predicted accurately?

The prognosis of individual patients with transient ischaemic attacks (TIAs) is extremely variable; some patients are at high risk and others at low risk of a serious vascular event. Prediction equations of outcome were developed, based on eight clinical prognostic factors, from a cohort of 469 hospital-referred TIA patients ("training" data set), that enable high (and low) risk patients to be identified and for whom costly and risky treatments may (or may not) be targeted. The study aimed to determine whether these equations are externally valid and can predict outcome, with reliability and discrimination, in two independent cohorts of TIA patients ("test" data sets): 1653 TIA patients in the UK-TIA aspirin trial and 107 TIA patients in the Oxfordshire Community Stroke Project. Predicted outcomes agreed closely with the observed outcomes in the "test" data sets (reliability) for all outcome events at low five year risk (< 30%) but the estimates of risk were less precise in groups predicted to have a high five year risk (> 40%). The prediction equations were fairly accurate in discriminating between patients who subsequently suffered the outcome event of interest and those who survived free of the event at five years after the TIA, particularly at lower cut-off levels distinguishing high and low risk (for example, < 30% vs > 30% at five years). It is very difficult to achieve perfect discrimination because there is no single important prognostic factor for TIA patients that indicates whether a patient is going to suffer an event or not. These equations can be used to provide a reliable estimate of the absolute five year risk of a serious vascular event in hospital-referred TIA patients but they cannot, as yet, be used with confidence to distinguish patients at high risk from patients at low risk.

Aged↗
PubMed1992

Transient ischaemic attacks: which patients are at high (and low) risk of serious vascular events?

The aims of this study were to determine the important prognostic factors at presentation which identify patients with transient ischaemic attacks (TIA) who are at high risk (and low risk) of serious vascular events and to derive a prediction model (equation) for each of the major vascular outcome events. A cohort of 469 TIA patients referred to a University hospital, without prior stroke, were evaluated prospectively and followed up over a mean period of 4.1 years (range 1-10 years). The major outcome events of interest were 1) stroke 2) coronary event and 3) stroke, myocardial infarction or vascular death (whichever occurred first). Prognostic factors and their hazard ratios were identified by means of the Cox proportional hazards multiple regression analysis. The significant adverse prognostic factors (in order of strength of association) for stroke were an increasing number of TIAs in the three months before presentation, increasing age, peripheral vascular disease, left ventricular hypertrophy and TIAs of the brain (compared with the eye); the prognostic factors for coronary event were increasing age, ischaemic heart disease, male sex, and a combination of carotid and vertebrobasilar TIAs at presentation; and for stroke, myocardial infarction or vascular death they were increasing age, peripheral vascular disease, increasing number of TIAs in the three months before presentation, male sex, a combination of carotid and vertebrobasilar TIAs at presentation, TIAs of the brain (compared with the eye), left ventricular hypertrophy and the eye), left ventricular hypertrophy and the eye), left ventricular hypertrophy and the presence of residual neurological signs after the TIA. Prediction models (equations) of both the relative risk and absolute risk of each of the major outcome events were produced, based on the presence or level of the significant prognostic factors and their hazard. Before it can be concluded that our equations accurately predict prognosis and can be generalised to other populations, their predictive power needs to be validated in other, independent samples of TIA patients (which we are currently doing).

Aged↗
PubMed1991

Prognosis and prognostic factors of retinal infarction: a prospective cohort study.

OBJECTIVE: To determine the prognosis and adverse prognostic factors in patients with retinal infarction due to presumed atheromatous thromboembolism or cardiogenic embolism. DESIGN: Prospective cohort study. SETTING: University hospital departments of clinical neurology. PATIENTS: 99 patients with retinal infarction, without prior stroke, referred to a single neurologist between 1976 and 1986 and evaluated and followed up prospectively until death or the end of 1986 (mean follow up 4.2 years). INTERVENTIONS: Cerebral angiography (55 patients), aspirin treatment (37), oral anticoagulant treatment (eight), carotid endarterectomy (13), cardiac surgery (six), and peripheral vascular surgery (two). MAIN OUTCOME MEASURES: Death, stroke, coronary events, contralateral retinal infarction; survival analysis confined to 98 patients with retinal infarction due to presumed artheromatous thromboembolism or cardiogenic embolism (one patient with giant cell arteries excluded), and Cox's proportional hazards regression analysis, including age as a prognostic factor. RESULTS: During follow up 29 patients died (21 of vascular causes and eight of non-vascular or unknown causes), 10 had a first ever stroke, 19 had a coronary event, and only one developed contralateral retinal infarction. A coronary event accounted for more than half (59%) of the deaths whereas stroke was the cause of only one death (3%). Over the first five years after retinal infarction the actuarial average absolute risk of death was 8% per year; of stroke 2.5% per year (7.4% in the first year); of coronary events 5.3% per year, exceeding that of stroke; and of stroke, myocardial infarction, or vascular death 7.4% per year. Prognostic factors associated with an increased risk of death were increasing age, peripheral vascular disease, cardiomegaly, and carotid bruit. Adverse prognostic factors for serious vascular events were increasing age and carotid bruit for stroke, and increasing age, cardiomegaly, and carotid bruit both for coronary events and for stroke, myocardial infarction, or vascular death. CONCLUSIONS: Patients who present with retinal infarction due to presumed atherothromboembolism or cardiogenic embolism are at considerable risk of a coronary event. The risk of stroke, although high, is not so great. Not all strokes occurring after retinal infarction relate directly to disease of the ipsilateral carotid system, although this is probably the most common cause. Few patients experience contralateral retinal infarction. Non-arteritic retinal infarction should be diagnosed or confirmed by an ophthalmologist, and the long term care of patients with the condition should involve a physician who has an active interest in managing vascular disease.

Age Factors↗
PubMed1991

Lacunar transient ischaemic attacks: a clinically useful concept?

Lacunar ischaemic stroke syndromes are clinically, pathophysiologically, and prognostically distinguishable from cortical ischaemic stroke syndromes. Could cerebrovascular transient ischaemic attacks (TIAs) share similar heterogeneity? 130 patients with TIAs were prospectively studied, 71 of whom underwent carotid angiography. Symptoms were associated with a 50% or greater stenosis of the ipsilateral internal carotid artery in 36 (67%) of 54 patients with presumed cortical TIAs, but in only 1 (6%) of 17 patients with presumed lacunar TIAs (p less than 0.0001). These findings support the view that cortical TIAs are associated with ipsilateral extracranial internal carotid artery atheromatous disease, whereas patients with lacunar TIAs may have absent or insignificant large-vessel disease, and probable intracranial small-vessel disease. Accurate distinction between lacunar and cortical events may have implications for investigation and treatment of patients with TIAs.

Aged↗
PubMed1991

The role of imaging in the management of cerebral and ocular ischaemia.

The last decade has seen several major technological advances in vascular neuroradiology, the most clinically significant of which have been the facility to image the brain and the extracranial carotid bifurcation noninvasively with accuracy and safety. Another major advance has been unequivocal evidence from formal statistical overviews that antiplatelet therapy, particularly aspirin, reduces the risk of serious vascular events by about 25%. These advances have changed clinical practice such that most patients presenting with symptoms suggestive of cerebral ischaemia should now have cranial CT to exclude intracerebral hemorrhage, not only because the causes and prognosis of cerebral ischaemia differ from those of intracerebral hemorrhage, but because many patients with cerebral ischaemia should be considered for antiplatelet therapy. Besides the use of long term antiplatelet therapy and control of vascular risk factors, other acute treatment options are limited with the possible exception of anticoagulation, thrombolysis, cytoprotective agents and carotid endarterectomy. If, as seems likely, the current clinical trials show that carotid endarterectomy plus medical therapy improve upon the stroke-free survival of patients treated medically, at least in symptomatic patients with severe stenosis, the number of carotid endarterectomies performed will increase considerably because carotid bifurcation disease is the most common cause of cerebral and ocular ischemic events. It will then be even more important to be able to obtain accurate anatomical and physiological information about the extracranial and intracranial circulations with utmost safety. Duplex ultrasound is currently the noninvasive screening method of choice for carotid bifurcation disease because it is available, relatively cheap, and reasonably accurate. It not only images the vessel lumen and degree of stenosis, but also the morphology of the vessel wall and associated plaque, the relevance of which is still uncertain in the pathogenesis of cerebral and ocular ischaemia. A major limitation of duplex sonography is that it cannot reliably distinguish tight stenosis from occlusion and it does not image the proximal or distal carotid circulation. The aim of newer techniques will be to distinguish tight extracranial carotid stenosis from occlusion and to provide anatomical, physiological and pathological information about the intracranial circulation and ischemic lesions (in view of potential for thrombolytic therapy of major intracranial vessel occlusion) with safety and reproducible accuracy.

Brain Ischemia↗
PubMed1991

The prognosis of hospital-referred transient ischaemic attacks.

A cohort of 469 hospital-referred patients with transient ischaemic attacks (TIA) of the brain (66%) or eye (34%) due to presumed atheromatous thromboembolism, lipohyalinosis or cardiogenic embolism, without prior stroke, was assembled between 1976-86. Follow up was prospective and complete until the patients death or the end of 1986. During a mean period of follow up of 4.1 years there were 82 deaths (58 vascular, 24 non-vascular), 63 first-ever strokes and 58 patients with coronary events. A coronary event accounted for 51% of deaths whilst stroke was the cause in 12%. The average risk of death over the first five years after TIA was 4.5% per year. The risk of stroke was 6.6% in the first year and 3.4% per year on average over the first five years. Stroke occurred in the same vascular territory as the initial TIA in about two-thirds of cases, and was of lacunar type in one fifth of these strokes. The average risk of a coronary event over the first five years after TIA was 3.1% per year, similar to that of stroke. However, the risk of a coronary event, and also death, was fairly constant each year after a TIA, in contrast to the risk of stroke which was highest in the first year. The average risk of stroke, myocardial infarction or vascular death over the first five years after TIA was 6.5% per year and the average risk of stroke, myocardial infarction or death from any cause was 7.5% per year. The prognosis of this cohort of hospital-referred TIA patients was better than that of TIA patients in the same community who presented to the Oxfordshire Community Stroke Project (OCSP), and reflected the impact of referral bias. The hospital-referred patients were younger, assessed at a later date after their last TIA, and comprised a greater proportion of patients who had had a TIA of the eye (amaurosis fugax), which had a better prognosis than TIA of the brain. Knowledge of the prognosis of different populations of TIA patients not only enhances understanding and interpretation of previous studies but is also required for optimal patient management and the planning of treatment trials.

Carotid Artery, Internal↗