The patient with transient ischemic attacks--is this the time for a new therapeutic approach?

Outcomes measured by mortality rates, quality of life and degree of autonomy in the first year in stroke units in Spain

Introduction

The primary objective of this sub analysis of the CONOCES study was to analyse outcomes in terms of mortality rates, quality of life and degree of autonomy over the first year in patients admitted to stroke units in Spain. The secondary objective was to identify the factors determining good prognosis.

Methods

We studied a sample of patients who had suffered a confirmed stroke and been admitted to a Stroke Unit in the Spanish healthcare system. Socio-demographic and clinical variables and variables related to the level of severity (NIHSS), the level of autonomy (Barthel, modified Rankin) and quality of life (EQ-5D) were recorded at the time of admission and then three months and one year after the event. Factors determining prognosis were analysed using logistic regression and ROC curves.

Results

A total of 321 patients were recruited, 33% of whom received thrombolytic treatment, which was associated with better results on the Barthel and the modified Rankin scales and in terms of the risk of death. Mean quality of life measured through EQ-5D improved from 0.57 at discharge to 0.65 one year later. Full autonomy level measured by Barthel index increased from 30.1% at discharge to 52.8% at one year and by the modified Rankin scale from 51% to 71%. The rates for in-hospital and 1-year mortality were 5.9% and 17.4% respectively. Low NIHSS scores were associated with a good prognosis with all the outcome variables. The three instruments applied (NIHSS, Barthel and modified Rankin scales) on admission showed good discriminative ability for patient prognosis in the ROC curves.

Conclusions

There has been a change in the prognosis for stroke in Spain in recent years as the quality of life at 1 year observed in our study is clearly higher than that obtained in other Spanish studies conducted previously. Moreover, survival and functional outcome have also improved following the introduction of a new model of care. These results clearly promote extension of the model based on stroke units and reinforced rehabilitation to the majority of the more than 100,000 strokes that occur annually in Spain.

Autopsy-verified causes of death after stroke

In a population-based sample of 409 stroke patients, autopsy was performed in 82 of the 95 patients who died during the first three months and in 61 of the 128 patients dying thereafter. The dominant causes of death, as verified by autopsy, were cerebrovascular disease in the first week (90%), pulmonary embolism in the second to fourth week (30%), bronchopneumonia during the second and third months (27%) and cardiac disease, mainly myocardial infarction, later than three months after the stroke (37%). Death was attributed to causes other than the brain lesion in 59% of the patients with ischemic and in 24% of the patients with hemorrhagic stroke (p less than 0.01). Age and sex had little influence on the distribution of causes of death. Fatal pulmonary embolism and bronchopneumonia surprisingly often occurred in ambulatory patients. An intracardiac thrombus was present in 20% of deceased patients with atrial fibrillation, and in 17% of cases with a history of myocardial infarction. When attempts are made to reduce mortality (and morbidity) after stroke, there would seem to be a considerable potential for prevention and early treatment of complications, such as pulmonary embolism, bronchopneumonia and cardiac disorders.

Cost-Effectiveness Analysis of Thrombolytic Treatment for Stroke

PURPOSE

Thrombolysis is used to treat stroke patients based on the National Institute of Neurological Disorders and Stroke study and meta-analysis results. We present a cost-effectiveness analysis based on a probabilistic model of the use of thrombolytic therapy in stroke treatment.

METHODS

We surveyed patients who had had a stroke during their hospital stay and examined them again 1 year after release from the hospital to obtain data on costs and natural history. We then calculated utility weights using the European Quality of Life Questionnaire. When the model runs, 4,000 Monte Carlo simulations are undertaken in which each parameter value changes depending on its probability distribution. The results are expressed in terms of the cost-effectiveness plane and the cost-effectiveness acceptability curve.

RESULTS

We studied 435 patients, of whom 304 had had an ischemic stroke. One year later, 216 were still alive. The mean utility values were 0.22 for disabled patients and 0.77 for autonomous patients. The incremental cost-effectiveness ratio (ICER) obtained by means of the parameters was -19,000 EUR/quality-adjusted life year, reflecting a saving of 6,000 EUR and a health benefit for patients. The cost-effectiveness plane showed that thrombolysis was a dominant variable in 96.1% of simulations. In the acceptability curves, only 0.4 of simulations obtained an ICER higher than the societal threshold.

CONCLUSIONS

Thrombolytic therapy seems to be a useful intervention because it is inexpensive and cost-effective. The key factor is the decreased rate of disability, which results in a better quality of life of the patient and lower costs.

Increasing severity of cardiovascular risk factors with increasing middle cerebral artery stenotic involvement in type 2 diabetic Chinese patients with asymptomatic cerebrovascular disease

OBJECTIVE

To identify determinants associated with increasing severity of middle cerebral artery (MCA) stenosis in asymptomatic Chinese type 2 diabetic patients with and without MCA stenosis determined using transcranial Doppler. Conventional risk factors contribute to the pathogenesis of ischemic stroke, and differences in the pattern of these may explain the heterogeneity of disease presentation in different populations. In Chinese patients, MCA stenosis is the most commonly identified intracranial vascular lesion.

RESEARCH DESIGN AND METHODS

Anthropometric and fasting biochemical parameters were compared between type 2 diabetic patients with MCA stenosis in one (n = 185) or both (n = 200) vessels and 1,492 type 2 diabetic patients without evidence of stenosis.

RESULTS

Increasing MCA stenotic vascular involvement was associated with significantly increasing age, duration of diabetes, systolic blood pressure, and LDL cholesterol, but with lower glucose levels. There was also an increased prevalence of hypertension, dyslipidemia, and use of blood pressure-and glucose-lowering agents in the patients with MCA stenosis. Concomitant significant increases in the prevalence of peripheral vascular disease and retinopathy were also observed in the patients with MCA stenosis.

CONCLUSIONS

Transcranial Doppler examination identified stenosis in one or both MCAs in over one-fifth of the Chinese type 2 diabetic subjects without symptoms of cerebrovascular disease. A number of conventional cardiovascular risk factors were closely associated with MCA stenosis. This technique may allow the identification of a particularly high-risk group, and further studies are required to determine whether asymptomatic MCA stenosis is predictive of primary cerebrovascular events and whether intensive treatment of risk factors would reduce the risk.

Prevalence and associations of MRI-demonstrated brain infarcts in elderly subjects with a history of transient ischemic attack. The Cardiovascular Health Study

BACKGROUND AND PURPOSE

MRI is more sensitive than CT, but the significance of brain abnormalities seen on MR images obtained in older subjects with transient ischemic attack (TIA) is not clear. We studied the prevalence and risk factors associated with MRI-demonstrated infarcts in elderly subjects with a history of TIA.

METHODS

Participants of the Cardiovascular Health Study, aged 65 years or more and without prior stroke, were studied with brain MRI (n=3456). The prevalence of brain infarcts (>/=3 mm) on MRI was determined in subjects with and without TIA. The cardiovascular risk factors and clinical and subclinical cardiovascular disease associated with MRI infarcts were studied in subjects with TIA.

RESULTS

Subjects with TIA (n=100) had a higher prevalence of MRI infarcts than subjects without TIA (46% versus 28%; P<0.001). The unadjusted odds ratio for having MRI infarcts in subjects with TIA was 2.20 (95% CI, 1.47 to 3.30) and remained significantly elevated after adjustments for risk factors and cerebrovascular disease (odds ratio, 1.86; 95% CI, 1.23 to 2.83). In subjects with TIA, diastolic blood pressure (P=0.01) and internal carotid artery intima-media thickness (P=0.01) were the only factors predictive of the presence of MRI infarcts by stepwise logistic regression analysis.

CONCLUSIONS

MRI infarcts are imaging manifestations of clinically important cerebrovascular disease in subjects with a history of TIA, given their increased prevalence and positive association with increased diastolic blood pressure and internal carotid artery intima-media thickness.

Prognostic significance of cerebrovascular disease in 11,526 chronic coronary artery disease patients. Bezafibrate Infarction Prevention (BIP) Study Group

Patients with chronic CAD and a history of cerebrovascular events were compared with patients without prior cerebrovascular events to assess the effect of these events on 5-year prognosis. Despite adjustment for older age and higher comorbidity among patients who had experienced a cerebrovascular event, a history of such an event was associated with an increased risk of 1.86 for total mortality.

Screening cerebrovascular patients for silent myocardial ischemia with stress testing and ambulatory left ventricular function monitor

Patients with symptomatic cerebrovascular disease suffer a high mortality from myocardial ischemia, which may occur during rest or following the conclusion of exercise. In a pilot study, we screened 11 patients with transient cerebral ischemic attack or stroke for silent myocardial ischemia using bicycle ergometer stress testing with electrocardiographic (EKG) monitoring and ambulatory left ventricular function monitoring (VEST). Three of 11 patients had nondiagnostic exercise EKGs due to failure to achieve their target heart rates during exercise but had positive VEST tests during and after exercise. One patient was falsely positive. VEST may be useful in combination with stress EKG for the detection of silent myocardial ischemia in cerebrovascular patients, but further assessment of the sensitivity and specificity in this patient population needs to be accomplished.

Frequency and prognostic significance of silent coronary artery disease in patients with cerebral ischemia undergoing carotid endarterectomy

To evaluate the prevalence and prognostic role of silent coronary artery disease (CAD) in patients with symptomatic high-grade carotid stenosis (70 to 99%) undergoing carotid endarterectomy, and with neither history nor symptoms of CAD, 106 patients (76 men, 30 women, mean age 58.7 years [range 42 to 71]) with recent cerebral ischemia were prospectively studied. Patients were stratified as to the presence (n = 27, 25%) or absence (n = 79, 75%) of silent CAD defined by concordant abnormal exercise electrocardiographic testing and thallium-201 myocardial scintigraphy. The male sex, the severity of the symptomatic carotid lesion (greater than 90%), and the coexistence of contralateral carotid disease identified patients with higher probability of coexisting CAD. The 106 patients underwent 121 operations (bilateral in 15). In the perioperative period, no deaths or cardiac events occurred, 1 patient suffered a recurrent stroke and 3 had a transient ischemic attack. During a mean follow-up period of 5.4 years, 9 patients died (1.7%/year): fatal myocardial infarction occurred in 5 (all in the silent CAD group), cancer in 3 and vertebrobasilar stroke in 1. Nonfatal events occurred in 9 patients: myocardial infarction in 1 (without silent CAD), unstable angina in 3 (with silent CAD), and cerebral ischemic attacks in 5. After 7 years, the Kaplan-Meier estimated survival free from coronary events was 51% in patients with silent CAD, and 98% in patients without CAD (p less than 0.01). In conclusion, among patients with symptomatic high-grade carotid stenosis undergoing carotid endarterectomy, even in absence of history or symptoms of CAD, a silent CAD is detectable in one fourth of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

René Descartes 1596-1650

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Cost-effective investigation of patients with suspected transient ischaemic attacks

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'Atypical TIAs' may herald cardiac rather than cerebral events

Sixty-four patients with atypical transient cerebral or visual symptoms that could not be classified as unequivocal TIAs nor as migraine, epilepsy or neurosis, were followed up for a mean of 3.75 years (range 11 months and 9 years, 240 patient years). Their mean age was 55 years. Only two patients suffered a (non-disabling) stroke, but eight patients had a major cardiac event: fatal myocardial infarction in three, sudden death in one and non-fatal myocardial infarction in four patients. Seven of these eight patients were known to have cardiovascular risk factors. Visual symptoms were relatively benign with regard to cardiac events (2 events in 28 patients), whereas dizziness alone and focal sensory symptoms alone were more strongly associated with subsequent cardiac complications (2 out of 4, and 4 out of 13 patients, respectively). In a control group of 185 patients with 'typical' TIAs or minor strokes, followed for a total of 233 patient years, seven patients had a ischaemic stroke, and only one a cardiac event. Our results suggest that patients with atypical transient cerebral deficits and cardiovascular risk factors may carry a low risk of subsequent stroke, but a high risk of major cardiac events.

Surgery to prevent stroke. High hopes and deep disappointment

Carotid endarterectomy and EC/IC bypass grafting have been widely adopted for patients considered at risk from stroke, without good evidence of efficacy. Unjustified claims for surgery usually derive from overestimating the dangers of the disease without surgery, while perioperative risks are underestimated. Inadequate follow-up and choosing irrelevant outcome measures often add to the confusion. All these factors apply to surgery for stroke. A trial of EC/IC bypass in 1,377 patients from three continents took 8 years to complete and showed no benefit in patients randomized to surgery. Reluctance to accept this result led to detailed critiques of this trial in several journals, largely based on the discovery that many patients had been operated on in some centers without having been randomized. In reply, the investigators showed that these cases did not affect the "resounding negativity of the results." Lack of good data about the prognosis of patients with TIAs or minor strokes was the fundamental reason for so much misplaced surgical effort. This applies equally to carotid endarterectomy, for which large trials are currently being completed. Had there been a reliable data base of patients at risk of stroke, prospectively collected and followed, the efficacy of these two operations could have been determined much sooner, and inappropriate diffusion might have been prevented.

Electroencephalographic monitoring for ischemia during carotid endarterectomy: visual versus computer analysis

In a retrospective study, we compared the use of computer-generated spectral electroencephalographic descriptors with a neurologist's interpretation of raw EEG data. Data were collected from patients undergoing carotid endarterectomy and anesthetized with isoflurane in nitrous oxide and oxygen. The EEG was recorded on magnetic tape during the period immediately before and after occlusion. These tapes were then analyzed off-line using a computer to generate averaged changes in 18 spectral descriptors. A strip-chart of raw EEG before and after the carotid occlusion was interpreted by a neurologist, who assigned changes in the EEG following occlusion to one of four visual inspection groups, depending on the severity of change. A descriptive examination of the distribution of changes in spectral descriptors revealed that no single descriptor adequately reflected the neurologist's interpretation of the raw EEG. Using data from 20 patients, the percent change from preocclusion to postocclusion values for total power, spectral edge frequency, spectral variance, and log spectral variance was examined. Only for the visual inspection group judged by the electroencephalographer to have the most severe ischemic change was there a significant difference in total power and log spectral variance. Although computer-processed EEG devices are of value as trending devices for detecting visual patterns associated with inadequate cerebral perfusion, single descriptors in this study did not consistently reflect a neurologist's diagnosis of ischemia. Single descriptors of spectral EEG analysis may not be sufficient to use as alarm variables in the recognition of cerebral ischemia.

Carotid endarterectomy. Who needs it?

Although carotid endarterectomy is one of the most frequently performed operations in this country, recent evidence casts doubt on its advisability, particularly for patients with ocular manifestations of cerebral ischemia. The following evidence is that: the risk of future stroke in untreated patients with amaurosis fugax, retinal plaques, and infarcts is less than 3% per year, far lower than that expected for cerebral (hemispheric) transient ischemic attacks (TIAs); the perioperative risk of stroke and death after endarterectomy may be much higher than previously suspected; and aspirin is a comparatively risk-free and moderately effective alternative to endarterectomy. Because of the questions raised about the risk-to-benefit ratio of endarterectomy, patients with ocular manifestations of cerebral ischemia should be considered for this operation only as part of a proposed randomized collaborative study.

Therapeutic progress--review XXIII. Are we making progress in the treatment of acute stroke?

The principal purpose of the treatment of acute stroke is to ensure that the quality of life of those affected is returned to as near normal as possible. Early nursing and physiotherapy are important components of effective management of acute stroke. It is not the intention of this review to examine these aspects which are so well described elsewhere (1). Instead, the theoretical and clinical bases for the various specific treatments advocated in recent years to reduce brain damage after ischaemic insult will be considered to serve as a guide for clinicians. Areas in this field where further research may prove rewarding are highlighted.

Internal carotid artery occlusion: clinical and therapeutic implications

Five hundred patients referred to the Cerebrovascular Clinic of the Johannesburg Hospital were examined by a battery of noninvasive tests and angiography. Thirty four occlusions of the internal carotid artery were found in 32 patients. These patients were prospectively evaluated, including clinical examination, analysis of risk factors and subsequent management. This group of patients was followed up for a mean period of 18 months, and the clinical and laboratory findings and follow up data of this group were compared to an age and sex matched group of patients with matched presenting symptoms, but with patent internal carotid arteries on angiography. Four clinical patterns emerged in the patients with occluded carotid arteries; asymptomatic (3), TIA's (17), initial fixed stroke (7), and TIA with subsequent stroke (5). Follow up of the occluded group revealed 19 patients (59%) with no further symptoms and no indication for surgical intervention. Nine patients required surgery; 4 external carotid endarterectomies (ipsilateral), 4 internal carotid endarterectomies (contralateral), and one extracranial to intracranial bypass. Two were lost to follow up and one died. After 18 months mean follow up 29 patients (91%) were well and asymptomatic. Follow up for a similar period of the non-occluded group revealed three deaths, three late strokes and three myocardial infarctions. None were lost to follow up. After 19 months mean follow up 26 patients (81%) were well with no new neurological symptoms. The prognosis of appropriately treated patients with total occlusion of the internal carotid artery does not appear to be worse than in patients with similar presenting features and patent carotid arteries.(ABSTRACT TRUNCATED AT 250 WORDS)