Natural History Of Unruptured Intracranial Aneurysms Research Articles

Spontaneous thrombosis of unruptured berry aneurysm presenting as facial palsy

Spontaneous thrombosis of saccular unruptured intracranial aneurysm (UIAs) is a known occurrence in giant aneurysms. However, spontaneous complete or partial thrombosis of non-giant aneurysms is a rare event in the natural history of UIAs that can be discovered incidentally on advanced neuroradiologic studies. They occasionally present with ischemic stroke, which is rare entity. Parent artery occlusion due to local extension of the luminal thrombus, aneurysms ejecting emboli to distal arteries, or increased mass effect have been described as possible pathogenic mechanisms. Guidelines for the management of these patients were limited. We present a documented case of this unusual entity a case of non-giant intracranial aneurysm with spontaneous thrombosis presenting as Upper motor neuron type of facial palsy due to acute ischemic stroke.

Biology, Physics and Genetics of Intracranial Aneurysm Formation: A Review.

Intracranial aneurysms (IAs) are persistent, localised dilatations of the arterial wall that are found in approximately 3% of the general population. The most severe complication of IAs is rupture, which results in devastating consequences such as subarachnoid haemorrhage and brain damage with serious neurological sequelae. Numerous studies have characterised the mechanisms underlying IA development and growth and identified a number of environmental modifiable (smoking, hypertension) and nonmodifiable risk factors (related to the histology of cerebral arteries and genetic factors) in its pathogenesis. Haemodynamic stress also likely plays a crucial role in the formation of IAs and is conditioned by the geometry and morphology of the vessel tree, but its role in the natural history of unruptured IAs remains poorly understood; it is believed that changes in blood flow might generate the haemodynamic forces that are responsible for damage to the vascular wall and vessel remodelling that lead to IA formation. This review summarises the most relevant data on the current theories on the formation of IAs, with particular emphasis on the roles of special conditions resulting from the microscopic anatomy of intracranial arteries, haemodynamic factors, bifurcation morphometry, inflammatory pathways, and the genetic factors involved in IA formation.

The natural course of unruptured intracranial aneurysms in a Chinese cohort: protocol of a multi-center registration study in CIAP

BackgroundSubarachnoid hemorrhage (SAH) accounts for 4.4% of cerebral vascular disease, which is one of the leading causes of death in China. Rupture of intracranial aneurysms (IAs) is the most common cause of SAH. The natural history of unruptured IAs (UIAs) and the risk factors for rupture are among the key issues regarding the pathogenesis of IA and SAH that remain unclear in the Chinese population.MethodsThe China Intracranial Aneurysm Project (CIAP) is a prospective, observational, multicenter registry study of the natural courses, risk factors for the onset and rupture, treatment methods, comorbidity management and other aspects of intracranial aneurysms. To date, there are five studies in the CIAP. CIAP-1 is a prospective observational cohort study of UIAs. More than 5000 patients who will be followed for at least 1 year are expected to be enrolled in this cohort. These participants come from more than 20 centers that represent different regions in China. Enrollment began on May 1, 2017, and will take approximately 5 years. A nationwide online database of UIAs will be built. Participants’ basic, lifestyle, clinical and follow-up information will be collected. The blood samples will be stored in the Central Biological Specimen Bank. Strict standards have been established and will be followed in this study to ensure efficient implementation.DiscussionThe natural course of UIAs in the Chinese population will be explored in this registry study. In addition, the risk factors for the rupture of the UIAs and the joint effect of those factors will be analyzed. The present study aims to create a nationwide database of UIAs and investigate the natural course of UIAs in China.Trial registration The Natural Course of Unruptured Intracranial Aneurysms in a Chinese Cohort (ClinicalTrials.gov Identifier: NCT03117803). Registered: July 5, 2017

Role of Hemodynamic Forces in Unruptured Intracranial Aneurysms: An Overview of a Complex Scenario.

An understanding of the natural history of unruptured intracranial aneurysms (IAs) has always played a critical role in presurgical or endovascular planning, to avoid possibly fatal events. Size, shape, morphology, and location are known risk factors for rupture of an aneurysm, but morphologic parameters alone may not be sufficient to perform proper rupture risk stratification. We performed a systematic PubMed search and focused on hemodynamics forces that may influence aneurysmal initiation, growth, and rupture. We included 223 studies describing several hemodynamic parameters related to aneurysm natural history. In these studies, different modalities of aneurysm model creation have been used to evaluate flow and to comprehensively analyze the evolution of IAs. Controversy exists about the correlation between these parameters and initiation, growth, rupture risk, or stabilization of the aneurysmal sac. Recent findings have also shown the importance of flow patterns in this process and the relationship between unruptured IA geometry and hemodynamic parameters. The role of hemodynamic forces in evaluation of the natural history of unruptured IAs presents is inherently complex and is still not completely understood. In this complex scenario, although several attempts have been described in the literature, a proper risk rupture stratification and treatment strategy selection based on hemodynamic forces has not yet been created. Further efforts should be made to accomplish this important goal.

Cerebral Aneurysms: Formation, Progression, and Developmental Chronology

The prevalence of unruptured intracranial aneurysms (UIAs) in the general population is up to 3%. Existing epidemiological data suggests that only a small fraction of UIAs progress towards rupture over the lifetime of an individual, but the surrogates for subsequent rupture and the natural history of UIAs are discussed very controversially at present. In case of rupture of an UIA, the case fatality is up to 50%, which therefore continues to stimulate interest in the pathogenesis of cerebral aneurysm formation and progression. Actual data on the chronological development of cerebral aneurysm has been especially difficult to obtain and, until recently, the existing knowledge in this respect is mainly derived from animal or mathematical models or short-term observational studies. Here, we review the current data on cerebral aneurysm formation and progression as well as a novel approach to investigate the developmental chronology of cerebral aneurysms.

Aspirin as a Promising Agent for Decreasing Incidence of Cerebral Aneurysm Rupture

See related article, pages 3156–3162. Approximately 2% of the general population harbor saccular intracranial aneurysms (IAs), lesions that are largely asymptomatic unless they rupture and produce a subarachnoid and/or intracerebral hemorrhage. The natural history of unruptured IAs, especially their propensity to bleed once discovered, remains controversial. Moreover, there is a poor understanding of several factors that may lead to IA rupture. One factor that has recently gained attention is the hypothesis that inflammation of the vessel and/or aneurysm wall may contribute in some way to a higher likelihood of rupture.1 However, data supporting the clinical relevance of this hypothesis are lacking. In the present submission,2 Hasan and colleagues use data from the International Study of Unruptured Intracranial Aneurysms (ISUIA)3 to indirectly address this issue. The ISUIA database likely comprises the most extensive retrospective and prospective database on patients harboring unruptured IAs and contains clinical outcome …

Not Tonight, Darling, I Might Get a Headache

See related article, pages 1878–1882 Advances in neuroimaging and an increase in the number of neuroimaging procedures performed have created a new management dilemma. Unruptured intracranial aneurysms (UIA) are found in ≈2% of people undergoing digital subtraction angiography1 and in 0.4% of people undergoing an MRI.2 The best risk management strategy in these patients is not known. Such patients are at increased risk for aneurysmal subarachnoid hemorrhage (SAH), but to know how they might best be managed, we need to understand more about the natural history of UIA, about factors that might provoke rupture, and about the risks and potential successes of intervention. In recent years, the Utrecht group,3 whose most recent work appears in this issue of Stroke , has contributed greatly to our understanding of these issues. The best estimate of the risk of rupture probably comes from the prospective arm of International Study of Unruptured Intracranial Aneurysms (ISUIA),4 which suggests an annual rupture risk of ≈0.1% for aneurysms 10 mm and most are in the anterior circulation. Paradoxically, despite this apparently very low rupture risk, most aneurysmal SAH appear to be attributable to rupture of small anterior circulation aneurysms. The most rational explanation, proposed by Wiebers et al5 and strongly supported by detailed mathematical modeling,6 is that most SAH arises from recently formed rather than long-standing aneurysms, although it is …

Treatment of unruptured intracranial aneurysms: Surgery, coiling, or nothing?

The decision of whether and how to treat an unruptured intracranial aneurysm (UIA) is complex. The goal in caring for patients with UIAs is to maximize their duration of high-quality life by optimally balancing the risks of aneurysm rupture--the "natural history" of the aneurysm--with those of treatment-related adverse outcomes. In this article, we review the literature concerning the natural history of UIAs and summarize the procedure-associated morbidity and mortality and efficacy of surgical clipping and endovascular coiling. Using this information, we make recommendations regarding the optimal management of patients with UIAs.