Transient ischemic attack and minor ischemic stroke: an algorithm for evaluation and treatment. Mayo Clinic Division of Cerebrovascular Diseases

Ischemic stroke pathophysiology: A bibliometric and visualization analysis from 1990 to 2022

Background

Pathophysiology plays a significant role in the scientific study of ischemic stroke, and has attracted increasing interest from researchers in the field. However, a comprehensive bibliometric analysis is lacking in this field. The purpose of this study is to identify the current research status and hotspots of ischemic stroke pathophysiology from a bibliometric perspective.

Methods

The Web of Science Core Collection database was searched for articles published from 1990 to 2022. CiteSpace, VOSviewer, and R package "bibliometrix" software were used to analyze countries/regions, institutions, journals, authors, papers, and keywords to predict the latest trends in ischemic stroke pathophysiology research.

Results

This analysis collected 7578 records of ischemic stroke pathophysiology. China and America emerged as the leading countries in this field, with Harvard University being the most active institution. Among journals and authors in this field, journal Stroke and author Gregory YH Lip published the most papers, while Nature Medicine was the journal with the highest citation per article. Keywords and co-citation clusters were closely related to "central nervous system", "mechanisms", "biochemistry & molecular biology" and "radiology, nuclear medicine & medical imaging", while other related fields, such as peripheral organs damage induced by the central nervous system and rehabilitation after ischemic stroke, require further research efforts.

Conclusion

This is the first bibliometric study that comprehensively mapped out the knowledge structure and development trends of ischemic stroke pathophysiology in recent 32 years, which may provide a reference for scholars to explore ischemic stroke pathophysiology.

Preoperative Assessment of Geriatric Patients Undergoing Elective Intracranial Surgery

A comprehensive preoperative assessment of elderly patients undergoing intracranial surgeries can reduce perioperative morbidity and mortality. Elderly patients often present with a wide array of comorbid medical conditions and extensive medication lists, which may influence the preoperative evaluation, anesthetic plan, and perioperative care. This article provides a basic overview of the preoperative assessment of elderly patients undergoing intracranial surgeries.

Is the ABCD Score Useful for Risk Stratification of Patients With Acute Transient Ischemic Attack?

Background and Purpose— A 6-point scoring system (ABCD) was described recently for stratifying risk after transient ischemic attack (TIA). This score incorporates age (A), blood pressure (B), clinical features (C), and duration (D) of TIA. A score <4 reportedly indicates minimal short-term stroke risk. We evaluated this scoring system in an independent population.

Methods— This was a prospective study of TIA patients (diagnosed by a neurologist using the classic <24-hour definition) hospitalized <48 hours from symptom onset. The primary outcome assessment consisted of dichotomization of patients into 2 groups. The high-risk group included patients with stroke or death within 90 days, ≥50% stenosis in a relevant artery, or a cardioembolic source warranting anticoagulation. All others were classified as low risk. Findings on diffusion-weighted MRI (DWI) were also evaluated when performed and patients classified as DWI+ or DWI−.

Results— Over 3 years, 117 patients were enrolled. Median time from symptom onset to enrollment was 25.2 hours (interquartile range 19.8 to 30.2). Overall, 26 patients (22%) were classified as high risk, including 2 strokes, 2 deaths, 15 with ≥50% stenosis, and 10 with cardioembolic source. The frequency of high-risk patients increased with ABCD score (0 to 1 13%; 2 8%; 3 17%; 4 27%; 5 26%; 6 30%; P for trend=0.11). ABCD scores in the 2 patients with stroke were 3 and 6. Of those who underwent MRI, 15 of 61 (25%) were DWI+, but this correlated poorly with ABCD score (0 to 1 17%; 2 10%; 3 36%; 4 24%; 5 13%; 6 60%; P for trend=0.24).

Conclusions— Although the ABCD score has some predictive value, patients with a score <4 still have a substantial probability of having a high-risk cause of cerebral ischemia or radiographic evidence of acute infarction despite transient symptoms.

Transient ischemic attack: review for the emergency physician

In the past few years, the approach to patients with transient ischemic attacks has undergone a transformation. To care for these patients, emergency physicians must understand these changes. They must be comfortable with the diagnosis and treatment of transient ischemic attacks in their emergency department. To this end, we ask and answer the following 6 important questions in this up-to-date review of transient ischemic attacks: (1) How is a transient ischemic attack defined? (2) Does this patient have a transient ischemic attack? (3) Once diagnosed, what diagnostic evaluation should be done (and when)? (4) What treatment should be instituted (and when)? (5) What is the correct disposition? and (6) What are the current medical guidelines?

The preoperative cerebrovascular consultation: common cerebrovascular questions before general or cardiac surgery

All types of health care providers may be called on to evaluate the risk of ischemic stroke related to an upcoming surgical procedure, particularly in patients with established cerebrovascular disease. We outline possible mechanisms contributing to perioperative stroke, summarize available data on the stroke risk associated with selected surgeries, and highlight recognized risk factors. We then provide recommended answers to some of the questions commonly encountered at the preoperative cerebrovascular consultation: What is the appropriate time interval between a stroke and elective surgery? What is the perioperative stroke risk for patients with established carotid or vertebrobasilar large artery stenosis, and what are the cardiac implications of detecting a cerebrovascular large artery stenosis? Should patients with a large artery stenosis undergo prophylactic revascularization procedures before undergoing general surgery? What treatment is appropriate for patients with both coronary artery and carotid or vertebrobasilar large artery stenosis? What is the appropriate perioperative management of antiplatelet and anticoagulant medications with respect to stroke risk?

Subtyping in ischemic stroke genetic research

Discovery of genes that influence stroke risk might be facilitated if phenotypic heterogeneity of the population studied were reduced by studying individual subtypes of stroke. Standardized systems for classifying stroke are generally mechanistic or syndromic. Mechanistic systems (eg, Trial of ORG10172 in Acute Stroke Treatment) are based on presumed pathophysiologic basis of occlusion. Syndromic systems (eg, Oxfordshire Community Stroke Project) are based on signs and symptoms of neurologic dysfunction. Linkage and candidate gene studies should use such standardized systems in the search for subtype-specific genetic risk factors to increase the validity of interstudy comparisons.

Cerebral infarction and transient ischemic attacks. Efficient evaluation is essential to beneficial intervention

Rapid but precise evaluation of patients presenting with cerebral infarction is essential to determine immediate intervention. Initial assessment should include history taking, physical examination, routine laboratory testing, electrocardiography, chest radiology, and noncontrast head CT. Localizing the event to the appropriate arterial circulation (anterior versus posterior) and determining topography (subcortical versus cortical) guide sequential testing to ascertain the mechanism of cerebral infarction. Diagnostic testing focuses on selectively identifying potential cardiac, large-vessel, small-vessel, or hematologic causes. Although diagnostic tools are evolving, 15% of cerebral infarctions still have an unknown cause or multiple potential sources.

Use of ambulatory electrocardiography for the detection of paroxysmal atrial fibrillation in patients with stroke. Canadian Task Force on Preventive Health Care

BACKGROUND

Patients with stroke commonly undergo investigations to determine the underlying cause of stroke. These investigations often include ambulatory electrocardiography to detect paroxysmal atrial fibrillation. There is conflicting evidence in the literature regarding whether routine ambulatory electrocardiography should be performed in all or selected stroke patients. This paper reviews the available evidence on (1) the yield of ambulatory electrocardiography in detecting paroxysmal atrial fibrillation in patients with stroke or transient ischemic attack and (2) the effectiveness of anticoagulation in preventing recurrent stroke in patients with paroxysmal atrial fibrillation.

METHODS

A MEDLINE search for primary articles was performed, and the references were reviewed manually. In addition, citations were obtained from experts. The evidence was systematically reviewed using the evidence-based methodology of the Canadian Task Force on Preventive Health Care.

RESULTS

Ambulatory electrocardiography can detect atrial fibrillation not found on initial electrocardiogram in between 1% and 5% of people with stroke. Ambulatory electrocardiography is generally safe. The risk of recurrent stroke in the setting of paroxysmal atrial fibrillation is uncertain, but appears to be similar to that seen with chronic atrial fibrillation (about 12% per year). Therapy with warfarin may reduce this risk by about two-thirds as compared to placebo. The annual risk of major bleeding with warfarin therapy is between 1% and 3% but rates for individual patients depend on various specific risk factors.

INTERPRETATION

There is insufficient evidence to recommend for or against the use of ambulatory electrocardiography for the detection of paroxysmal atrial fibrillation in either selected or unselected patients with stroke (C Recommendation). There is fair evidence to recommend therapy with warfarin for patients with stroke and paroxysmal atrial fibrillation (B Recommendation).

Anticoagulation in neurosurgical patients

OBJECTIVE

Few recommendations have been outlined in the neurosurgical literature regarding when it is safe to initiate postoperative or posthemorrhage anticoagulation (AC), or for what duration it is safe to discontinue AC therapy in patients with clear indications for AC therapy. Our objective was to formulate guidelines for managing AC in neurosurgical patients, based on patients' needs for AC and the risk of complications.

METHODS

We conducted a systematic review of the neurosurgical and general surgical literature pertaining directly to postoperative or posthemorrhage management of AC. In addition, we surveyed the general medical, cardiology, cardiothoracic surgery, general surgery, vascular surgery, and neurology literature to determine the risk of thromboembolic complications when AC is stopped in specific patient groups.

RESULTS

Postoperative bleeding complications occurred more frequently when correction of coagulation abnormalities was inadequate in the preoperative period, when AC was reinstituted in the early (24-48 h) postoperative period, and when AC was supratherapeutic in the postoperative period. Risk of significant thromboembolic complications while off AC varied significantly depending on the primary disease process necessitating AC.

CONCLUSION

Adequate preoperative correction of coagulation abnormalities and strict regulation of coagulation to avoid supratherapeutic AC is essential. Reintroduction of AC after an intracranial hemorrhage treated without surgery, or after a neurosurgical procedure, particularly an intracranial procedure, can be guided by determining whether the patient is at high, moderate, or low risk for thromboembolic complications. On the basis of experimental studies, the patient's thromboembolic risk, and the experience of other surgeons, we propose therapeutic options for use of AC in neurosurgical patients undergoing intracranial procedures.