Screening for familial intracranial aneurysms

Prevalence of unruptured intracranial aneurysms among first-degree relatives of Thai patients who had aneurysmal subarachnoid hemorrhage

Background:

The prevalence of familial unruptured intracranial aneurysm (UIA) in Thai population was unknown.

Methods:

Our study population comprised first-degree relatives of patients who were diagnosed with aneurysmal subarachnoid hemorrhage (aSAH) in two cerebrovascular neurosurgical centers from January 2018 to December 2018. The volunteers underwent three-dimensional time-of-flight magnetic resonance angiography for screening intracranial aneurysms (IA). Those who were reported positive or suspected of IA then underwent computed tomography angiography for confirmation.

Results:

We identified 12 patients who had 12 unruptured IAs (UIAs) from among 93 first-degree relatives. The prevalence of UIA among our study population was 12.9%. An estimated prevalence of UIA among Thai population was 9.05% (95% confidence interval [CI] 7.32–10.78). Of the 93 relatives, 84 had only one first-degree relative who suffered aSAH. Siblings posed a higher risk for UIA than offspring (16% vs. 9.5%), but the difference was not statistically significant (odds ratio 1.810, 95% CI 0.50–6.50, P = 0.274). The most common aneurysm location was the anterior cerebral artery territory (50%).

Conclusion:

The prevalence of familial UIA in a Thai population was relatively high. There was no significant between-group difference in the occurrence of UIA between the siblings and offspring of the aSAH patients.

Familial Intracranial Aneurysms in Saudi Arabia: What Do We Need To Do?

Aneurysmal subarachnoid hemorrhage (SAH) is a devastating event with significant morbidity and mortality. The incidence of SAH might be influenced by environmental factors but genetic predisposition is evolving as an important effector in the risk of development of intracranial aneurysms and rupture of aneurysms. This requires strategies for effective screening of family members at risk of developing such a phenotype, in order to deliver preventive treatment to these target lesions. We discuss the potential for implementing these strategies in the Saudi Arabian health system and the future implications on our care for such a vulnerable group of subjects.

Epidemiology of intracranial aneurysms of Mississippi: a 10-year (1997-2007) retrospective study

BACKGROUND

Despite massive efforts, progress so far has been modest in isolating the genetic determinants for intracranial aneurysm (IA). More detailed epidemiology data might be essential for successful genome-wide association study. Here, we aimed to investigate epidemiology and identify the key risk factors associated with the pathogenesis of IA in a large specific population.

METHODS

We investigated the epidemiology and analyzed the risk factors of IA pathogenesis by using an International Classification of Diseases, Ninth Revision database search of the patients treated at the University of Mississippi Medical Center, Jackson, MS, within the past 10-year period (1998-2007). All recruited patients were interviewed to assess multiple risk factors and comorbidities (hypertension, tobacco abuse, females sex, diabetes mellitus, coronary artery disease, coronary obstructive pulmonary disease, alcohol abuse, stroke, hyperlipidemia, illicit drug use, and family history).

RESULT

In this retrospective study, we identified several significant risk factors among well-defined human subjects. The 3 major risk factors identified for our IA population are hypertension, tobacco abuse, and female sex. However, African American race was not a significant risk factor in our study. Furthermore, top two risk factors (hypertension, tobacco abuse) were found to be highly associated with familial cases.

CONCLUSIONS

In this study, using a specific and well-defined large population, we reported that some key risk factors were further confirmed to be strongly associated with the pathogenesis of IA whereas further investigation into racial factors is apparently needed. Our finding of the confounding effects of top risks with familial cases further complicated the genetic analysis of IA.

Sudden adult death

In the investigation of sudden death in adults, channelopathies, such as long QT syndrome, have risen to the fore in the minds of forensic pathologists in recent years. Examples of these disorders are touched upon in this review as an absence of abnormal findings at postmortem examination is characteristic and the importance of considering the diagnosis lies in the heritable nature of these conditions. Typically, a diagnosis of a possible channelopathy is evoked as an explanation for a 'negative autopsy' in a case of apparent sudden natural death. However, the one potential adverse effect of this approach is that subtle causes of sudden death may be overlooked. The intention of this article is to review and discuss potential causes of sudden adult death (mostly natural) that should be considered before resorting to a diagnosis of possible channelopathy. Nonetheless, it becomes apparent that many of the potential causes of sudden death can have a genetic basis. Thus, it becomes an important consideration that there may be a genetic basis to sudden death that extends beyond the negative autopsy.

Molecular Genetics of Human Intracranial Aneurysms

Intracranial aneurysms (IAs) are the dilatations of blood vessels in the brain and pose potential risk of rupture leading to subarachnoid hemorrhage. Although the genetic basis of IAs is poorly understood, it is well-known that genetic factors play an important part in the pathogenesis of IAs. Therefore, the identifying susceptible genetic variants might lead to the understanding of the mechanism of formation and rupture of IAs and might also lead to the development of a pharmacological therapy. To elucidate the molecular pathogenesis of diseases has become a crucial step in the development of new treatment strategies. Although extensive genetic research and its potential implications for future prevention of this often fatal condition are urgently needed, efforts to elucidate the susceptibility loci of IAs are hindered by the issues bewildering the most common and complex genetic disorders, such as low penetrance, late onset, and uncertain modes of inheritance. These efforts are further complicated by the fact that many IA lesions remain asymptomatic or go undiagnosed. In this review, we present and discuss the current status of genetic studies of IAs and we recommend comprehensive genome-wide association studies to identify genetic loci that underlie this complex disease.

Estimates of maternal risks of pregnancy for women with hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu syndrome): suggested approach for obstetric services

OBJECTIVES

Hereditary haemorrhagic telangiectasia (HHT) affects 1 in 5-8000 individuals. Pregnancy outcomes are rarely reported. The major reason is that most women do not have their HHT diagnosed prior to pregnancy. Using a large well-characterised series, we studied all pregnancies known to have occurred in HHT-affected women, whether or not their diagnosis was known at the time of pregnancy. Our aim was to estimate rates and types of major complications of HHT in pregnancy, to guide management decisions.

DESIGN

Cohort study, with prospective, retrospective and familial components.

SETTING/POPULATION

Tertiary referral centre population.

METHODS

All 262 pregnancies in the 111 women with HHT and pulmonary arteriovenous malformations (PAVMs) reviewed between 1999 and 2005 were studied. Eighty-two women (74%) did not have a diagnosis of HHT/PAVM at the time of pregnancy. 222 pregnancies in their 86 HHT-affected relatives were also studied.

MAIN OUTCOME MEASURES

PAVM bleed, stroke and maternal death.

RESULTS

Thirteen women experienced life-threatening events during pregnancy: 1.0% (95% CI 0.1-1.9) of pregnancies resulted in a major PAVM bleed; 1.2% (0.3-2.2%) in stroke (not all were HHT related); and 1.0% (0.13-1.9%) in maternal death. All deaths occurred in women previously considered well. In women experiencing a life-threatening event, prior awareness of HHT or PAVM diagnosis was associated with improved survival (P = 0.041, Fisher's exact test).

CONCLUSIONS

Most HHT pregnancies proceed normally. Rare major complications, and improved survival outcome following prior recognition, means that pregnancy in a woman with HHT should be considered high risk. Recommendations for pregnancy management are provided.

HIV and cerebral aneurysms

Patients infected with the human immunodeficiency virus (HIV) or suffering from acquired immunodeficiency syndrome (AIDS) are now surviving for longer periods of time secondary to improvements in medical management. As the classical causes of morbidity and mortality in this patient population have come under better control, new complications are becoming more prevalent. In our clinical practice, there appears to have been a rise in the number of patients with HIV infection and AIDS who have experienced aneurysmal subarachnoid hemorrhage (SAH). In this paper, we review the available literature regarding cerebral aneurysms in patients infected with HIV and/or suffering from AIDS.

Unruptured intracranial aneurysms: benign curiosity or ticking bomb?

15 years ago, the treatment of incidentally discovered intracranial aneurysms was straightforward with a good evidence base behind it. When intracranial aneurysms were identified, people were referred to neurosurgeons who would offer surgical repair if the patient was in reasonable health and had a good life expectancy. Since that time, several studies have given contradictory evidence for what should be done with these lesions, and a new technique for the repair of aneurysms, endovascular coil embolisation, has been developed. Here we review the research and make several recommendations. First, incidentally discovered aneurysms in the anterior circulation less than 7 mm in size in people with no personal or family history of subarachnoid haemorrhage should be left untreated. Second, people with remaining life expectancy of less than 20 years or so (ie, those over age 60 years) should be informed that from a statistical point of view the benefits of treatment do not outweigh the risks. Third, in all other cases treatment with surgical clipping or coil embolisation should be advised. And finally, if surgical treatment is not feasible then medical hypotensive treatment may be a viable alternative.

Prevalence of intracranial aneurysms in first-degree relatives of patients with aneurysms

Object

A familial predisposition toward cerebral aneurysms has been previously described in patients with two or more affected family members. In the present study the familial incidence of unruptured intracranial aneurysms was studied in 96 patients with at least one first-degree relative (parent, sibling, or child) in whom a cerebral aneurysm was diagnosed.

Methods

All patients were between 20 and 70 years of age and underwent three-dimensional fast–spin echo magnetic resonance imaging. Sixty-one patients (63.5%) were women. The majority of patients (84%) were caucasian and the remainder were Hispanic (13%) or African-American (3%). No patient suffered a medical condition (excluding hypertension and smoking) known to be associated with cerebral aneurysm formation.

In four patients at least one aneurysm was found (two harbored multiple aneurysms). Three of the four patients were women. Two of the patients were siblings. The estimated prevalence in first-degree relatives was 4.2% (95% confidence interval 1.2–10.1). Of note, the mean age in the current study population was 39 years. The authors of recent metaanalyses have suggested that the prevalence of nonfamilial aneurysms is approximately 2%, despite earlier reports in which higher figures were cited.

Conclusions

The authors conclude that first-degree relatives of patients with aneurysms are at higher risk for harboring an intracranial aneurysm.

Computed tomography scan of the head in patients with migraine or tension-type headache

A retrospective study was performed in order to evaluate the frequency of abnormalities found by computed tomography (CT) scan of the head in 78 patients with migraine or tension-type headache. In the present study CT scan was normal in 61.5% of the patients with migraine or tension-type headache. A number of abnormalities were encountered in more than one third of the patients studied, including inflammatory sinus disease (19.2%), cysticercosis (3.9%), unruptuted cerebral aneurysm (2.6%), basilar impression (2.6%), intracranial lipoma (2.6%), arachnoid cyst (2.6%), empty sella (2.6%), intracranial neoplasm (2.6%), and others (2.6%). None of these lesions were symptomatic or responsible by the headache picture, therefore, considered incidental findings. In conclusion, the fortuitous encounter of some abnormalities on CT scan of the head is often higher than what we could predict in patients suffering migraine or tension-type headache. We briefly discuss clinical, epidemiologic, and practical management of some of the abnormalities detected by CT scan as well as the indication to request a neuroimaging investigation.

The influence of hemodynamic stress factors on intracranial aneurysm formation

OBJECT

Applanation tonometry is a noninvasive method of assessing both peripheral and central arterial blood pressure (BP) profiles. In this study the authors examine whether there are differences in these profiles in patients with intracranial aneurysms when compared with age-matched controls.

METHODS

Carotid artery (CA) and derived aortic BP waveforms were obtained using a pulse wave analysis system. The ratio of the pressure wave amplitude above the systolic shoulder to the total systolic BP (augmentation index [AI]) was recorded. One hundred seventy-three patients with intracranial aneurysms (23 unruptured lesions) and 173 healthy control volunteers were examined. For the patients with aneurysms the right and left CA AIs (mean +/- standard deviation) were 125.6 +/- 23.1% and 128.3 +/- 22.1%, respectively. Corresponding values for the control group were 118.4 +/- 22.6% and 119.4 +/- 21.8%. The calculated AI for the ascending aorta was 29.8 +/- 10.5% and 25.6 +/- 12.2% for patients with aneurysms and control volunteers, respectively. Significant asymmetry in CA AI was seen in patients with aneurysms, the left being greater (p = 0.002). No significant differences were seen in mean BP (108 +/- 14 mm Hg in patients with aneurysms compared with 106 +/- 16 mm Hg in controls; p = 0.2). Multivariate analysis excluded the influence of BP and other potential confounding vascular risk factors for increased AI.

CONCLUSIONS

Significant differences in AI, both in magnitude and symmetry, were identified in patients with intracranial aneurysms when compared with matched controls.