Diagnosis and management of ischemic stroke. Part I.--Threatened stroke and its management

Vascular dementia: still a debatable entity?

Vascular dementia (VAD) is currently considered to be the second most common cause of dementia in Europe and the USA, second to dementia of the Alzheimer's type (DAT). However, in Asia and many developing countries the incidence of VAD exceeds that of DAT. The positive clinical diagnostic workup for VAD requires six steps: (1) clear-cut quantitative assessment of cognitive deficits utilizing standard neuropsychological tests to establish and quantify the dementia syndrome and rule out pseudo-dementia OF depression; (2) ascertaining the presence of risk factors for stroke; (3) identifying cerebral vascular lesions by neuroimaging (MRI, Iodine or Xenon contrasted CT, PET and SPECT); (4) exclusion of other causes of dementia; (5) differential diagnosis of possible, probable or definite VAD versus DAT and ascertaining when there are mixtures of the two; and (6) temporal identification of causality between onset and progression of the dementia with identified cerebral vascular lesions. There are eight subtypes of VAD: (1) multi-infarct dementias. These are due to large cerebral emboli, and are usually readily identifiable; (2) strategically placed infarctions causing dementia; (3) multiple subcortical lacunar lesions. Patients with these develop VAD at least five to twenty-five times more frequently than those in age-matched general population samples; (4) Binswanger's disease (arteriosclerotic subcortical leuko-encephalopathy). This form is rare. Neuroimaging confirms the diagnosis during life but the diagnosis can not be made by neuroimaging alone; (5) mixtures of two or more of above VAD subtypes; (6) hemorrhagic lesions causing dementia; (7) subcortical dementias due to cerebral autosomally dominant arteriolopathy with subcortical infarcts and leuko-encephalopathy (CADASIL), or to familial amyloid angiopathies and coagulopathies all of which present with multiple subcortical lacunar lesions similar to Binswanger's disease; (8) mixtures of DAT and VAD. The clinical significance of leukoaraiosis and its suspected relationships to VAD remains to be better established. The presence of ischemic infarctions, single or multiple large or multiple small (lacunar) by neuroimaging are necessary for the diagnosis of VAD, but identifying their presence, by neuroimaging alone, does not permit the diagnosis of dementia which can only be established by neuropsychological assessments. VAD is a clinical entity, identifiable in at least 30-70% of patients after strokes but mechanisms responsible for the cognitive impairments are complex. Some of these mechanisms are incompletely understood but provide subjects for important future research.

Heterogeneity of vascular dementia: mechanisms and subgroups

Today, multiple, thromboembolically generated cerebral infarcts are regarded as the main pathogenetic pathway of vascular dementia (VAD), with multi-infarct dementia (MID) as its clinical counterpart. However, taking into account other vascular mechanisms that may influence the brain, such as vessel-wall damage (atherosclerosis, hyalinosis, amyloid angiopathy, or blood-brain barrier dysfunction), cerebrovascular insufficiency (disturbance of systemic circulation, perfusion vulnerability related to the vascular anatomy of the brain, or disturbance of autoregulation), and hyperviscosity, it is evident that MID is not the only VAD category. The diagnosis of MID ought to be reserved for the combination of progressive dementia associated with cerebral ischemic events and evidence of infarction that is mainly associated with the large cerebral arteries. Subcortical white-matter dementia characterized by frontosubcortical symptomatology, white-matter lesions, and small-vessel involvement with or without lacunes/infarcts--a combination of lacunar dementia and Binswanger's disease--appears to be another important VAD disease.

Current management of amaurosis fugax. The Amaurosis Fugax Study Group

We present a consensus on the pathophysiology, etiology, diagnosis, and treatment of amaurosis fugax. The phenomenon is defined and described, and the roles that extracranial and ocular vascular diseases play are discussed. Nonvascular ophthalmic and neurologic disorders that can be confused with amaurosis fugax are listed, and an algorithm for evaluation (which includes ophthalmic examination, laboratory studies, and noninvasive carotid artery studies) is given. Treatment of atherosclerosis, carotid artery disease, and other causes of amaurosis fugax are also discussed.

A randomized trial comparing ticlopidine hydrochloride with aspirin for the prevention of stroke in high-risk patients. Ticlopidine Aspirin Stroke Study Group

We report the results of the Ticlopidine Aspirin Stroke Study, a blinded trial at 56 North American centers that compared the effects of ticlopidine hydrochloride (500 mg daily) with those of aspirin (1300 mg daily) on the risk of stroke or death. The medications were randomly assigned to 3069 patients with recent transient or mild persistent focal cerebral or retinal ischemia. Follow-up lasted for two to six years. The three-year event rate for nonfatal stroke or death from any cause was 17 percent for ticlopidine and 19 percent for aspirin--a 12 percent risk reduction (95 percent confidence interval, -2 to 26 percent) with ticlopidine (P = 0.048 for cumulative Kaplan-Meier estimates). The rates of fatal and nonfatal stroke at three years were 10 percent for ticlopidine and 13 percent for aspirin--a 21 percent risk reduction (95 percent confidence interval, 4 to 38 percent) with ticlopidine (P = 0.024 for cumulative Kaplan-Meier estimates). Ticlopidine was more effective than aspirin in both sexes. The adverse effects of aspirin included diarrhea (10 percent), rash (5.5 percent), peptic ulceration (3 percent), gastritis (2 percent), and gastrointestinal bleeding (1 percent). With ticlopidine, diarrhea (20 percent), skin rash (14 percent), and severe but reversible neutropenia (less than 1 percent) were noted. The mean increase in total cholesterol level was 9 percent with ticlopidine and 2 percent with aspirin (P less than 0.01). The ratios of high-density lipoprotein and low-density lipoprotein to total cholesterol were similar in both treatment groups. We conclude that ticlopidine was somewhat more effective than aspirin in preventing strokes in this population, although the risks of side effects were greater.

The ocular ischemic syndrome. II. Mortality and systemic morbidity

The cases of 52 consecutive persons with ocular ischemic syndrome (ocular symptoms and signs attributable to severe carotid artery obstruction) were studied. Followup disclosed a five year mortality of 40%. In comparison, an age and sex matched control group from the Framingham study had a five year mortality of 11%. The leading cause of death was cardiac disease (63%), while stroke was second (19%). Other associated diseases included systemic arterial hypertension (73%), diabetes mellitus (56%) and peripheral vascular disease (19%).

Clinical and radiologic features of lacunar versus nonlacunar minor stroke

We determined the angiographic presence of extracerebral and intracerebral arterial disease in 122 patients with minor stroke within the carotid territory; we excluded patients with a recognized cardiac source of emboli. Based on clinical features and computed tomographic findings, patients were classified as having lacunar infarcts (n = 61), nonlacunar infarcts (n = 53), and infarcts of indeterminate type (n = 8). Severe carotid bifurcation disease (greater than or equal to 50% stenosis or occlusion) was significantly more common in nonlacunar than in lacunar infarcts, on both the ipsilateral (p less than 0.001) and the contralateral (p less than 0.01) sides; 79% of the patients with nonlacunar infarcts had severe carotid bifurcation and/or middle cerebral artery disease on the ipsilateral side compared with 3.3% of the patients with lacunar infarcts. Our data underscore the need for classification of patients by the underlying mechanisms in future studies of treatment of ischemic stroke.

Amaurosis fugax: the importance of carotid plaque morphology

Amaurosis fugax, or transient monocular blindness, was first associated with carotid bifurcation disease in 1951. Although amaurosis fugax is often considered by vascular surgeons to be premonitory for cerebral stroke, recent studies indicate that this disease process may be more benign than previously thought. A total of 97 patients presented with amaurosis fugax to our vascular laboratory from November 1983 to January 1988. There were 81 males and 16 females, mean age 67.2 years. The common, internal and external carotid arteries were imaged in standard longitudinal and cross-sectional views. Repeat scans were performed at six months and 12 months after the first visit, then yearly thereafter. Out study confirms the correlation between heterogeneous, complex carotid plaques and the development of amaurosis fugax. Endarterectomy can safely be performed in this group of patients, preventing further symptoms or development of stroke. We advocate duplex scanning to assess the carotid bifurcation and allow non-invasive follow-up of disease progression.

Types of multi-infarct dementia

A series of 79 patients with multi-infarct dementia (MID) were divided into 2 groups designated cortical MID and subcortical MID, according to whether the computed tomography (CT) scan showed the presence or absence of cortical infarcts, and an absent to mild or moderate to severe degree of white matter low attenuation (WMLA). Cortical MID was characterized by repeated atherothrombotic and cardiogenic strokes, moto-sensory hemiparesis, a severer degree of aphasia, and abrupt onset of cognitive failure. Subcortical MID typically showed the following features: lacunar strokes, bulbar signs including dysarthria, pure motor hemiparesis, depression and emotional lability. WMLA was found in all patients with subcortical MID but also in over 60% of those with cortical MID. In the 2 groups CT scans showed equal frequencies of deep infarcts. When divided according to severity of WMLA, 92% of patients in the cortical MID group and 44% of those in the subcortical MID group were found to have at least one cortical infarct on the CT scan. Although cortical and subcortical MID differed in several clinical features, they did not show major differences in the risk factors for stroke, and clearly overlapped each other as regards ischaemic scores and the findings in neurological examinations and CT. Thus, it is still an open question whether cortical MID and subcortical MID, including the lacunar state and Binswanger's disease, are 2 distinct entities or merely represent the expression of biological variation while having the same etiopathogenesis.

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.

Major cerebral infarction from tumor embolus

A major right hemispheric infarct developed in a 31-year-old man within forty-eight hours of lung resection for metastatic synovial-cell sarcoma. Post mortem exam revealed tumorous occlusion of the right internal carotid artery. Major stroke from cerebral tumor embolus should be seriously considered in patients with primary or metastatic lung cancer who have had a very recent pneumonectomy, especially when there are symptoms and signs of multi-organ or extremity ischemia.