Ischemic Stroke and Patent Foramen Ovale: Risk Factors and Genetic Profile

A meta-analysis of the association of atrial septal abnormalities and atrial vulnerability

BACKGROUND

The mechanism of cryptogenic stroke (CS) in patients with atrial septal abnormalities remains unclear, and the increased incidence of atrial vulnerability may be one of the reasons. We performed this meta-analysis to clarify the association between atrial septal abnormalities and atrial vulnerability, and to provide evidence-based basis for the prevention and mechanism of CS.

METHODS

We systematically searched for studies on the association between atrial septal abnormalities and atrial vulnerability, and pooled available data on types of atrial septal abnormalities, types of atrial vulnerability, and methods of atrial vulnerability detection. The primary endpoints were the occurrence of atrial arrhythmias or P wave abnormalities. Random-effects models were used to calculate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Twelve case-control studies were eligible. Compared with the control group, patients with atrial septal abnormalities had a higher risk of atrial vulnerability (OR: 1.93; 95% CI: 1.13-3.30, P = .02). Data based on stroke patients showed that the group with atrial septal abnormalities had a higher risk of atrial vulnerability than the control group (OR: 2.00; 95% CI: 1.13-3.53, P = .02). However, there was no significant difference in the incidence of atrial vulnerability between the 2 groups of nonstroke patients. Subgroup analysis showed that although atrial septal abnormality increased the risk of atrial vulnerability in the subgroup of atrial septal aneurysm (OR: 1.68; 95% CI: 0.47-5.95, P = .42), the subgroup of atrial fibrillation (AF)/atrial fluster (OR: 1.81; 95% CI: 0.94-3.46, P = .07) and the subgroup of subcutaneous recording system (OR: 1.33; 95% CI: 0.68-2.61, P = .41), the difference was not statistically significant.

CONCLUSIONS

Atrial septal abnormalities can increase the risk of atrial vulnerability, and atrial arrhythmia caused by atrial septal abnormalities may be one of the mechanisms of CS.

Patent Foramen Ovale in Fetal Life, Infancy and Childhood

A patent foramen ovale (PFO) is a common, incidental echocardiographic finding in otherwise healthy and asymptomatic infants and children. However, a variety of clinical conditions have been ascribed to the presence of a PFO in childhood, such as cryptogenic stroke, platypnea-orthodeoxia syndrome, decompression sickness and migraine, although the data on these are controversial and sometimes contradictory. This review discusses embryology and correlation with post-natal anatomy, anatomical variations of the atrial septum, diagnostic modalities in special circumstances of PFO associated clinical syndromes, and the role of PFO in congenital heart disease, pulmonary hypertension, dilated cardiomyopathy and heart failure in children who require an extracorporeal membrane oxygenator or ventricular assist device as life support.

The association between apolipoprotein A1-C3-A5 gene cluster promoter polymorphisms and risk of ischemic stroke in the northern Chinese Han population

Objective

Given its effects on lipid metabolism, the apolipoprotein A1-C3-A5 (APOA1-C3-A5) gene cluster is thought to play an important role in ischemic stroke pathogenesis. Here, we evaluated whether the APOA1-C3-A5 cluster is associated with ischemic stroke in the northern Chinese Han population.

Methods

This case–control study analyzed 812 patients with ischemic stroke and 844 healthy controls with regard to four APOA1-C3-A5 cluster promoter single nucleotide polymorphisms (SNPs), rs670, rs2854116, rs2854117, and rs662799, using the SNaPshot Multiplex sequencing assay. Potential associations among ischemic stroke, genotyping, and allele frequencies were assessed.

Results

APOA1 rs670 CT/TT genotypes, APOA5 rs662799 AG/GG genotypes, and the APOC3 rs2854116 CC genotype were associated with an increased risk of ischemic stroke according to multivariate logistic analysis after adjusting for confounding factors. A significantly increased risk for ischemic stroke was also identified among high-risk haplotypes (C-C-T-A and T-T-C-A) for rs670–rs2854116–rs2854117–rs662799.

Conclusion

This study showed that rs670, rs2854116, and rs662799 SNPs of the APOA1-C3-A5 cluster are associated with ischemic stroke in the northern Chinese Han population.

Effect of Selective 5-HT6R Agonist on Expression of 5-HT Receptor and Neurotransmitter in Vascular Dementia Rats

Background

5-HT6 receptor (5-HT6R) has pluripotent roles regulating secretion of neurotransmitters. However, whether 5-HT6R is involved in the development of vascular dementia (VD) remains unclear. To evaluate the role and mechanism of 5-HT6R in VD, this study established a rat VD model to evaluate the effect of selective 5-HT6R agonist on the expression of 5-HT6R mRNA and neurotransmitter.

Material/Methods

Eighty healthy male SD rats (7 weeks old) were randomly assigned to sham, model, 5-HT6R agonist, and placebo groups (N=20 each). A rat VD model was generated by permeant bilateral ligation of the common carotid artery. 5-HT6R agonist, placebo, or saline were given intraperitoneally for 4 weeks. The Morris water maze was utilized to test learning and memory function. Brains were extracted to separate the cortex and hippocampal tissues, in which glutamate and γ-aminobutyric acid (GABA) levels were analyzed. mRNA and protein levels of 5-HT6R were determined by RT-PCR and immunohistochemistry (IHC), respectively.

Results

Model rats had longer escape latency and fewer crossing platform times. Contents of DA, Glu, GABA, and Ach were lowered in cortical and hippocampal tissues, and 5-HT6R expression was suppressed (p<0.05). The application of 5-HT6R agonist shortened escape latency and increased the number of passing through the platform. It also improved hippocampal CA1 neuronal damage and elevated DA, Glu, GABA, and Ach contents and expression of 5-HT6R. Expression of 5-HT6R was not different from the placebo group.

Conclusions

Selective 5-HT6R agonist can alleviate learning deficit of VD rats, possibly via improving neurotransmitter levels in brain regions.

Patent Foramen Ovale and Stroke

A patent foramen ovale (PFO) is common and found in nearly 25% of healthy individuals. The majority of patients with PFO remain asymptomatic and they are not at increased risk for developing a stroke. The presence of PFO, however, has been found to be higher in patients with cryptogenic stroke, suggesting there may be a subset of patients with PFO who are indeed at risk for stroke. Paradoxical embolization of venous thrombi through the PFO, which then enter the arterial circulation, is hypothesized to account for this relationship. Although aerated-saline transesophageal echocardiography is the gold standard for diagnosis, aerated-saline transthoracic echocardiography and transcranial Doppler are often used as the initial diagnostic tests for detecting PFO. Patients with cryptogenic stroke and PFO are generally treated with antiplatelet therapy in the absence of another condition for which anticoagulation is necessary. Based on the findings of 3 large randomized clinical trials, current consensus guidelines do not recommend percutaneous closure, though this is an area of controversy. The following review discusses the relationship of PFO and cryptogenic stroke, focusing on the epidemiology, pathophysiological mechanisms, diagnostic tools, associated clinical/anatomic factors and treatment. (Circ J 2016; 80: 1665-1673).

Patent foramen ovale

Patent foramen ovale (PFO) is the most common congenital heart abnormality of fetal origin and is present in approximately ∼25% of the worldwide adult population. PFO is the consequence of failed closure of the foramen ovale, a normal structure that exists in the fetus to direct blood flow directly from the right to the left atrium, bypassing the pulmonary circulation. PFO has historically been associated with an increased risk of stroke, the mechanism of which has been attributed to the paradoxical embolism of venous thrombi that shunt through the PFO directly to the left atrium. However, several studies have failed to show an increased risk of stroke in asymptomatic patients with a PFO, and the risk of stroke recurrence is low in patients who have had a stroke that may be attributed to a PFO. With the advent of transoesophageal and transthoracic echocardiography, as well as transcranial Doppler, a PFO can be routinely detected in clinical practice. Medical treatment with either antiplatelet or anticoagulation therapy is recommended. At the current time, closure of the PFO by percutaneous interventional techniques does not appear to reduce the risk of stroke compared to conventional medical treatment, as shown by three large clinical trials. Considerable controversy remains regarding the optimal treatment strategy for patients with both cryptogenic stroke and PFO. This Primer discusses the epidemiology, mechanisms, pathophysiology, diagnosis, screening, management and effects on quality of life of PFO.

Prevalence of migraine headache in an in-patient stroke population

INTRODUCTION

Migraine, especially with aura, is a risk factor for ischemic stroke. In this study, we investigated descriptive data and prevalence of migraine in an in-patient stroke population.

MATERIALS AND METHODS

Patients with acute cerebrovascular disease (CVD) admitted to the stroke unit during a 6-month period were recruited. Prevalence of migraine was assessed using a structured questionnaire. Additional clinical data regarding risk factors for CVD were evaluated for all responding patients.

RESULTS

A total of 229 patients received a questionnaire and 175 answers were collected (response frequency of 76.4%). Responders matched the initial cohort regarding distribution of age, sex, and type of stroke. Thirty-six cases (20.6%) fulfilled the criteria for migraine or probable migraine according to the 2nd edition of the International Headache Classification (ICHD-2). Sixty percent of migraine patients had migraine with aura. Stroke patients with migraine were younger (P = 0.007), the presence of patent foramen ovale (PFO) was significantly increased (P = 0.008), and atrial fibrillation was less common (P = 0.048). There were no other differences between patients with and without migraine headache regarding conventional risk factors.

CONCLUSIONS

The prevalence of migraine in this hospital-based stroke cohort was comparable to the estimated prevalence of migraine usually described in population studies. In our study population, the prevalence of migraine with aura was higher than expected. The increased prevalence of PFO in patients with migraine headache corresponds well to previous population studies.

Prevalence of Patent Foramen Ovale in Ischaemic Stroke in Italy: Results of SISIFO Study

BACKGROUND

Although several authors have studied the association between patent foramen ovale (PFO) and ischaemic stroke, the matter is still controversial; few have suggested an association between cryptogenetic stroke and PFO, while others have denied this association. The aim of this study was to evaluate PFO prevalence in the whole ischaemic stroke population, independently from age and stroke subtypes and to identify the characteristics associated with the presence of PFO.

METHODS

SISIFO study was a multicenter, prospective, single-wave, cross-sectional survey conducted on consecutive patients with acute ischemic stroke admitted to selected clinical centres. Data regarding vascular risk factors were registered for each patient; all patients underwent computed tomography scan and/or magnetic resonance imaging of the brain; an electrocardiogram and standard laboratory blood tests were performed. A Doppler ultrasound study of extra-cranial arteries was performed too. The cases were classified according to TOAST and OCSP criteria. Each patient underwent transcranial Doppler or transcranial color-coded duplex sonography with bubble test as diagnostic tool for right-to-left-shunt. Where right-to-left shunt was detected, PFO presence was confirmed by echocardiography.

FINDINGS

1,130 consecutive patients were included. We found a PFO in 247 (21.9%; 95% CI, 19.5-24.3%) patients; PFO was present in 23.5% of patients with cryptogenic stroke and in 21.3% of patients with stroke of known causes; this difference was not statistically significant. At the univariate analysis, decreasing age, hypertension, diabetes mellitus, and atrial fibrillation, and stroke characteristics such as NIHSS, OCSP and TOAST were predictors of PFO presence. At the multivariate analysis, we found a significant interaction between age and OCSP syndrome. Being LACI the reference category, the prevalence of PFO in PACI and POCI decreased significantly along with age, whereas there was no change in TACI.

CONCLUSION

If any relationship exists between stroke and PFO, this is more likely in PACI and POCI at a younger age. Our results are consistent with recent findings that underline PFO alone must not be considered a significant independent predictor for stroke; so the presence of PFO alone doesn't permit rushed causal correlations or 'therapeutic aggressiveness'.

Ischemic stroke as the first manifestation of hepatic epithelioid hemangioendothelioma

A 38-year-old obese woman, with a past medical history of cholecystectomy and dyslipidaemia, presented with acute occipital headache, vomiting and rotational vertigo which lasted 8 hours. On admission neurological examination was unremarkable, however general physical examination revealed hepatomegaly. Routine blood tests showed abnormal liver function tests. MRI scan indicated an acute ischemic infarct in the right cerebellum. Extensive investigation was negative. However, liver MRI revealed multiple lesions in both liver lobes. Ultrasound guided liver biopsy and histopathological analysis confirmed the diagnosis of hepatic hemangioendothelioma. In conclusion, hypercoaguable state related to hepatic epithelioid hemangioendothelioma can lead to an ischemic stroke, as a rare first manifestation of the disease.