PubMed Health⌕ Search

Biomedical subjects

Louis R Caplan

Publications and source records attributed to Louis R Caplan.

At least 19 recordsLinked to original sources
PubMed2007

Why identification of stroke syndromes is still important.

PURPOSE OF REVIEW: Recent trends in the practice of stroke neurology lay a strong and excessive reliance on data generated from large epidemiological and clinical trials to direct patient care. This article highlights some of the pitfalls of this approach. It discusses the continuing importance of identifying stroke syndromes in implementing individualized patient care. RECENT FINDINGS: Stroke is a heterogeneous disease and occurs through a variety of mechanisms. With the help of examples, the article illustrates some of the complexities of clinical decision making in an individual patient. Some important recent advances in the diagnostic and treatment armamentarium for stroke are also discussed. SUMMARY: Identification of stroke syndromes remains an important tool in the rational management of stroke patients.

Adult↗
PubMed2007

Use of stents to treat intracranial cerebrovascular disease.

Intracranial atherosclerosis is a common cause of stroke. Although it has been recognized for decades, the lack of successful treatment strategies has limited clinical interest until recently. We review the natural history and pathophysiology of intracranial atherosclerosis. Vascular biomechanics are important to define differences between cerebral arteries and extracranial vessels and partly explain the technical challenges facing cerebral artery revascularization as compared with revascularization of coronary arteries. Pharmacological interventions to prevent stroke have had limited success, but technological developments offer improved methods for endovascular revascularization of symptomatic and asymptomatic cerebral artery stenosis. Identification of appropriate candidates for treatment also remains a challenge, and our knowledge about the natural history of the disease is limited. At this time, patients with significant intracranial stenosis should receive information on the benefits and risks of revascularization therapy. Determining which patients should undergo revascularization procedures will require carefully planned, randomized clinical trials.

Angioplasty, Balloon↗
PubMed2007

Pitfalls in the diagnosis of cerebellar infarction.

BACKGROUND: Cerebellar infarctions are an important cause of neurologic disease. Failure to recognize and rapidly diagnose cerebellar infarction may lead to serious morbidity and mortality due to hydrocephalus and brain stem infarction. OBJECTIVES: To identify sources of preventable medical errors, the authors obtained pilot data on cerebellar ischemic strokes that were initially misdiagnosed in the emergency department. METHODS: Fifteen cases of misdiagnosed cerebellar infarctions were collected, all seen, or reviewed by the authors during a five-year period. For each patient, they report the presenting symptoms, the findings on neurologic examination performed in the emergency department, specific areas of the examination not performed or documented, diagnostic testing, the follow-up course after misdiagnosis, and outcome. The different types of errors leading to misdiagnosis are categorized. RESULTS: Half of the patients were younger than 50 years and presented with headache and dizziness. All patients had either incomplete or poorly documented neurologic examinations. Almost all patients had a computed tomographic scan of the head interpreted as normal, and most of these patients underwent subsequent magnetic resonance imaging showing cerebellar infarction. The initial incorrect diagnoses included migraine, toxic encephalopathy, gastritis, meningitis, myocardial infarction, and polyneuropathy. The overall mortality in this patient cohort was 40%. Among the survivors, about 50% had disabling deficits. Pitfalls leading to misdiagnosis involved the clinical evaluation, diagnostic testing, and establishing a diagnosis and disposition. CONCLUSIONS: This study demonstrates how the diagnosis of cerebellar infarction can be missed or delayed in patients presenting to the emergency department.

Adult↗
PubMed2006

Patterns of cerebral perfusion in patients with asymptomatic internal carotid artery disease.

BACKGROUND: The perfusion profile of patients with asymptomatic internal carotid artery (ICA) disease has not been well studied. The purpose of this study is to describe the perfusion patterns of patients with asymptomatic ICA disease using computed tomography perfusion (CTP) and its potential value in identifying patients at higher risk for transient ischemic attacks (TIAs) or strokes. METHODS: We analyzed 32 patients with asymptomatic high grade ICA disease who had CTP and computed tomography angiography (CTA) of the head and neck. Twenty-four patients had severe ICA stenosis and eight had ICA occlusion. The degree of ipsilateral external carotid artery (ECA) and contralateral ICA stenosis, patency of the anterior communicating artery (ACOM), A1 segment and posterior communicating artery (PCOM) were evaluated in all patients. RESULTS: Sixteen patients had normal CTP and the other 16 patients had cerebral hypoperfusion, characterized by abnormalities in one or more of the three perfusion maps. Ipsilateral hypoplastic A1 segment was more frequent in the group with cerebral hypoperfusion (p = 0.025). Ipsilateral TIAs occurred in two patients, both with cerebral hypoperfusion. CONCLUSION: Cerebral hypoperfusion is present in half of the patients with asymptomatic ICA disease, predominantly in patients with a hypoplastic ipsilateral A1 segment. These patients likely represent a higher-risk group for symptomatic brain ischemia.

Adult↗
PubMed2006

Antiplatelet therapy in stroke prevention: present and future.

White platelet-fibrin thrombi often form on roughened endothelial surfaces and unstable arterial plaques. Agents that reduce the tendency of platelets to aggregate, agglutinate, and secrete and to attach to endothelial surfaces have been explored as agents that prevent brain and heart infarction. Aspirin, ticlopidine, clopidogrel, dipyridamole, cilostazol, and glycoprotein llb/llla inhibitors are all used now and have various different modes of action and functions.

Aspirin↗
PubMed2006

Cardiac encephalopathy and congestive heart failure: a hypothesis about the relationship.

Many patients with congestive heart failure develop neurologic dysfunction. This may take the form of a cardiac encephalopathy that shares clinical features with other metabolic encephalopathies. The causes are multiple. There is a particular, previously unreported, syndrome that occasionally develops in some patients with congestive heart failure that resembles the findings in patients with normal pressure hydrocephalus. This syndrome is characterized by apathy and abulia with preserved alertness; it is caused by fluid retention within the cranial cavity. The syndrome may also develop in patients with other conditions that cause anasarca, e.g., severe liver or kidney disease or hypoalbuminemia. Because patients with these conditions are often quite ill, it has been difficult to verify the pathophysiologic aspects of the syndrome so that its mechanism must remain a hypothesis that awaits more definitive study in a series of patients. I have not seen this syndrome discussed in any cardiology or neurology texts or reports, and it seems to be completely unknown to cardiologists and neurologists. I have recognized about one patient per year with this syndrome.

Aged↗
PubMed2006

Is hypoperfusion an important cause of strokes? If so, how?

Traditionally hypoperfusion and embolism are considered separate important causes of stroke in patients with arterial occlusive disease. However, although hypoperfusion and embolism differ in mechanisms and location, they generally coincide in severe obstructive lesions and cause washout disturbances of embolism in low perfusion territories distal to stenosis. Unless the collateral blood supply is sufficient to prevent ischemia, multiple remote spot-like infarctions occur within the hypoperfused brain territory. In border-zone distributed infarction - long suspected to result from hemodynamic compromise alone - complementary interaction of embolisation and hypoperfusion territories has to be considered. Thus hypoperfusion with embolism or embolism alone are the most common explanations for stroke, the former often associated with less severe clinical deficits than the latter.

Arterial Occlusive Diseases↗
PubMed2006

Vertebral artery compression of the medulla.

BACKGROUND: Intracranial arteries in the subarachnoid space may compress the brain parenchyma and cranial nerves. Most arterial compressive lesions have been attributed to dolichoectasia in the vertebral-basilar system, and prior reports have concentrated on the pressure effects of basilar artery ectasia. Much less is known about vertebral artery compression of the medulla. OBJECTIVE: To describe a series of patients with vertebral arteries compressing the medulla oblongata. DESIGN: Prospective case studies. SETTING: Tertiary care center. PATIENTS: Nine symptomatic patients, 4 men and 5 women, between the ages of 32 and 79 years. MAIN OUTCOME MEASURES: Clinical phenomena, radiographic findings, treatment, and outcomes. RESULTS: We found that compression most commonly occurs at the ventrolateral surface. The clinical features can be transient or permanent and are predominantly motor and cerebellar or vestibular, but a poor correlation exists between the clinical findings and the severity or extent of impingement. The vertebral arteries were angulated, tortuous, or dilated but not necessarily dolichoectatic to cause obvious indentation. Seven patients were treated with antiplatelets and anticoagulants or analgesics, whereas 2 underwent microvascular decompression, resulting in temporary or no relief. One surgical patient developed cranial nerve complications. Among the medically treated patients, none had progression of deficits, and those with single episodes had no recurrence of symptoms. CONCLUSION: This study is the largest collection, to our knowledge, of patients with medullary vascular compression. Further studies are needed to estimate its frequency, natural course, and preferred management.

Adult↗
PubMed2006

National Stroke Association guidelines for the management of transient ischemic attacks.

OBJECTIVE: Transient ischemic attacks are common and important harbingers of subsequent stroke. Management varies widely, and most published guidelines have not been updated in several years. We sought to create comprehensive, unbiased, evidence-based guidelines for the management of patients with transient ischemic attacks. METHODS: Fifteen expert panelists were selected based on objective criteria, using publication metrics that predicted nomination by practitioners in the field. Prior published guidelines were identified through systematic review, and recommendations derived from them were rated independently for quality by the experts. Highest quality recommendations were selected and subsequently edited by the panelists using a modified Delphi approach with multiple iterations of questionnaires to reach consensus on new changes. Experts were provided systematic reviews of recent clinical studies and were asked to justify wording changes based on new evidence and to rate the final recommendations based on level of evidence and quality. No expert was allowed to contribute to recommendations on a topic for which there could be any perception of a conflict of interest. RESULTS: Of 257 guidelines documents identified by systematic review, 13 documents containing 137 recommendations met all entry criteria. Six iterations of questionnaires were required to reach consensus on wording of 53 final recommendations. Final recommendations covered initial management, evaluation, medical treatment, surgical treatment, and risk factor management. INTERPRETATION: The final recommendations on the care of patients with transient ischemic attacks emphasize the importance of urgent evaluation and treatment. The novel approach used to develop these guidelines is feasible, allows for rapid updating, and may reduce bias.

Health Planning Guidelines↗
PubMed2006

Transient ischemic attack: definition and natural history.

The standard definition of a transient ischemic attack--"a cerebral dysfunction of an ischemic nature lasting no longer than 24 hours with a tendency to recur"--was arrived at arbitrarily and is no longer tenable. Experience shows that attacks are much briefer, usually less than an hour, and many are associated with brain infarction. A newer definition, more consonant with the data, is preferred--"transient ischemic attack is a brief episode of neurological dysfunction caused by focal brain or retinal ischemia, with clinical symptoms typically lasting less than an hour, and without evidence of acute infarction." Patients with transient ischemic attacks require urgent evaluation that includes brain and vascular imaging, blood tests, and often cardiac investigations. Treatment will depend on the nature of the causative cervico-cranial vascular, cardiac, and hematologic abnormalities found on investigation.

Humans↗
PubMed2006

Neurology case studies: cerebrovascular disease.

Data from randomized therapeutic trials often provide little relevant evidence for therapeutic decisions physicians make daily. By illustrating the nuances of these four complex cases involving cerebrovascular disease, the authors stress the importance of more time spent by specialists at the bed-side, exploring patients' symptoms and learning their thoughts, fears, biases, and wishes.

Adult↗
PubMed2006

Use of stents to treat extracranial cerebrovascular disease.

Stent-assisted carotid angioplasty (CAS) is increasingly utilized for hemodynamically significant stenoses of the extracranial carotid artery. Carotid endarterectomy (CEA) is still considered the gold standard in the management of symptomatic hemodynamically significant carotid stenoses. However, endovascular device technology is rapidly evolving and the recent introduction of embolic filtration devices (EFD) proved to reduce periprocedural stroke rates in CAS considerably. Several randomized multicenter trials are currently recruiting patients to compare CAS with EFD to carotid endarterectomy in different cohorts, such as patients at high surgical risk for CEA and those with asymptomatic stenosis. The review presents current developments in CAS.

Angioplasty↗
PubMed2006

Angioplasty and stenting to treat occlusive vascular disease.

The advent of effective percutaneous treatment of occlusive vascular lesions by angioplasty and stenting is one of the most important contributions to medical care early in the 21st century. Evaluation of angioplasty and stenting procedures is still in a very early phase. New types of stents and other technologies and devices are being continuously developed and there is a definite learning curve. The experience, training, and number of procedures clearly relate to outcomes, and many different specialists are still learning and so far have not had optimal experience. This review provides an overview of studies that have examined the efficacy of stenting in conjunction with balloon angioplasty for carotid atherosclerosis compared with endarterectomy. Also discussed are angioplasty/stenting of other neck arteries and intracranial arteries and the key issues surrounding percutaneous intervention, including patient selection criteria, clinical assessment of lesions most suitable for treatment, the use of distal protective devices and drug-eluting stents, and recommendations for physician selection.

Angioplasty, Balloon↗