Embolic stroke
Pro Research Analysisby 
Searched over 200M research papers for "embolic stroke"
Consensus Meter
Understanding Embolic Stroke: Key Insights and Research Findings
Introduction to Embolic Stroke
Embolic stroke occurs when a blood clot or other debris forms away from the brain—commonly in the heart—and is swept through the bloodstream to lodge in narrower brain arteries. This type of stroke is characterized by a sudden onset of symptoms, with severity peaking at the onset. The affected areas are typically within the territories supplied by the major branches of the anterior cerebral artery (ACA), middle cerebral artery (MCA), or posterior cerebral artery (PCA).
Embolic Stroke of Undetermined Source (ESUS)
Definition and Prevalence
The term "Embolic Stroke of Undetermined Source" (ESUS) was introduced to describe nonlacunar ischemic strokes with no clear etiology despite thorough diagnostic workup. ESUS accounts for approximately 17% of all ischemic strokes and is more common in younger patients with mild strokes . Unlike cryptogenic strokes, which include multiple stroke etiologies or incomplete diagnostic workups, ESUS is a more specific classification.
Diagnostic Challenges and Imaging
Identifying the source of embolism in ESUS is crucial but often challenging. Magnetic resonance imaging (MRI) has proven valuable in detecting potential cardiac and vascular embolic sources, such as atrial cardiomyopathy and supracervical atherosclerosis. The addition of MRI to conventional diagnostic workups can reclassify a significant percentage of ESUS cases, thereby reducing the prevalence of undetermined sources.
Risk Factors and Recurrence
Potential Embolic Sources
Common sources of embolism include cardiac conditions like atrial fibrillation, left atrial or ventricular thrombus, and valvular diseases. Other sources can be found in the aortic arch, great vessels, or venous system, especially in the presence of an intracardiac shunt. Despite extensive testing, up to 40% of ischemic strokes remain cryptogenic, suggesting an embolic mechanism.
Recurrence and Prognosis
Patients with ESUS have an annual stroke recurrence rate of 4% to 5% . Recurrent strokes are often more severe and disabling, particularly when associated with atrial fibrillation. The NAVIGATE-ESUS trial highlighted that most recurrent strokes after ESUS were embolic and of undetermined source, emphasizing the need for more extensive investigations to identify the embolic source.
Treatment Strategies
Anticoagulation vs. Antiplatelet Therapy
The hypothesis that anticoagulation could reduce stroke recurrence in ESUS patients was tested in large trials like NAVIGATE ESUS and RE-SPECT ESUS. However, these trials yielded neutral results, suggesting that anticoagulation may not be universally superior to antiplatelet therapy for secondary prevention in ESUS . The ATTICUS trial is currently investigating whether early anticoagulation with apixaban is more effective than acetylsalicylic acid in preventing new ischemic lesions in ESUS patients.
Personalized Treatment Approaches
Recent studies suggest that ESUS cases resulting from subclinical atrial fibrillation, atrial cardiopathy, or unrecognized myocardial infarction may benefit more from anticoagulation. In contrast, cases linked to nonstenosing large-artery atherosclerosis or aortic atherosclerosis may not respond as well to this treatment, indicating the need for personalized therapy.
Conclusion
Embolic stroke, particularly ESUS, presents significant diagnostic and therapeutic challenges. Advances in imaging and a better understanding of stroke pathophysiology are crucial for improving patient outcomes. While anticoagulation shows promise for certain subgroups, personalized treatment strategies based on the underlying cause of embolism are essential for effective stroke prevention. Ongoing research and clinical trials will continue to refine these approaches, aiming to reduce the burden of recurrent strokes in ESUS patients.
Sources and full results
Most relevant research papers on this topic