Inherited thrombophilic disorders in young adults with ischemic stroke and patent foramen ovale

Patent foramen ovale: The never-ending story

Several uncontrolled studies suggested a relationship between patent foramen ovale (PFO) and stroke. But recent data indicate that previous studies may overestimate the association between PFO and stroke. First, among patients who have had a cryptogenic stroke under treatment (with either warfarin or aspirin), the main data from the French PFO/atrial septal aneurysm (ASA) and PICSS (Patent Foramen Ovale in Cryptogenic Stroke Study), analyzed separately and in combination, indicate that PFO alone does not announce a significantly increased risk of recurrent stroke or death. But a small increase or decrease in risk cannot be excluded by this meta-analysis. Second, the data concerning the association between PFO and ASA are not clear and variable: the French PFO/ASA study found a significantly increased risk of recurrent stroke in patients with cryptogenic stroke and an association between PFO and ASA when treated medically. In contrast, PICSS found no association between the combined PFO-ASA with stroke or death, but the two populations had meaningful differences. Patients in the PICSS were much older than those in the French PFO/ASA study and had more risk factors for stroke, such as hypertension, diabetes, and history of prior stroke. Third, there were inadequate data to conclude about ASA alone. Possible practice recommendations could come from this meta-analysis: the evidence indicates that the risk of recurrent stroke or death is not different for patients with a PFO who underwent cryptogenic stroke compared to patients without a PFO who underwent a cryptogenic stroke under treatment with either aspirin or warfarin. But aspirin is more preferable (300 mg/d). However, it seems that the association between PFO and ASA confers an increased risk of recurrent stroke in medically treated patients who are less than 55 years of age. This subgroup of younger stroke patients may benefit from other treatments, such as the percutaneous closure of PFO or mini-invasive surgery to a lesser extent, but their efficacy and safety are not yet assessed by large randomized trials. However, we must also keep in mind that some stroke patients with PFO are psychologically attached to their PFO and prefer to close it.

What Proportion of Stroke Is Not Explained by Classic Risk Factors?

Ischemic stroke is a complex entity with multiple etiologies and variable clinical manifestations. The most frequent cause of stroke is atherosclerosis of cerebral vasculature followed by cardioembolism. Two thirds of strokes are explained by identifiable risk factors. Age, hypertension, and nonvalvular atrial fibrillation are by far the most frequent and well documented ones. Approximately 5% of strokes are caused by conditions other than atherosclerosis or heart disease, i.e., cervical arteries dissections, nonatherosclerotic vasculopathies, infectious or systemic vasculitis, and collagen vascular diseases. In spite of a thorough diagnostic evaluation, 30% of strokes remain cryptogenic, i.e., no specific cause is identified and the classic risk factors are not present. Identification of unknown environmental or genetic risk factors should be the subject of further research.

Polymorphisms of the Interleukin-1β Gene Affect the Risk of Myocardial Infarction and Ischemic Stroke at Young Age and the Response of Mononuclear Cells to Stimulation In Vitro

Objectives— To investigate the role of interleukin-1β (IL-1β) gene polymorphisms as a link between inflammation, coagulation, and risk of ischemic vascular disease at young age.

Methods and Results— A total of 406 patients with myocardial infarction (MI) at young age, frequency-matched for age, sex, and recruitment center, with 419 healthy population-based controls and 134 patients with ischemic stroke at young age, matched by age and sex, with 134 healthy population-based controls, were studied. Subjects carrying the TT genotype of the −511C/T IL-1β polymorphism showed a decreased risk of MI (odds ratio [OR], 0.36; 95% CI, 0.20 to 0.64) and stroke (OR, 0.32; 95% CI, 0.13 to 0.81) after adjustment for conventional risk factors. In both studies, the T allele showed a codominant effect ( P =0.0020 in MI; P =0.021 in stroke). Mononuclear cells from volunteers carrying the T allele showed a decreased release of IL-1β and a decreased expression of tissue factor after stimulation with lipopolysaccharide compared with CC homozygotes. The presence of a monoclonal antibody against IL-1β during cell stimulation resulted in a marked reduction of tissue factor activity expression.

Conclusions— -511C/T IL-1β gene polymorphism affects the risk of MI and ischemic stroke at young age and the response of mononuclear cells to inflammatory stimulation.

Comparison of results of percutaneous closure of patent foramen ovale for paradoxical embolism in patients with versus without thrombophilia

We investigated the efficacy of transcatheter patent foramen ovale (PFO) closure to prevent recurrent cerebral ischemic events in patients who did and those who did not have thrombophilia. Patients who have a PFO and an associated thrombophilia may have an increased risk of cerebral ischemic events. Seventy-two consecutive patients (mean age 42 +/- 13 years) underwent percutaneous PFO closure because of a cerebral stroke (51%) or a transient ischemic attack (49%). A thrombophilia was found in 20 patients (28%). A large right-to-left shunt through the PFO was found in 44 patients (61%) and an atrial septal aneurysm was found in 39 (54%). After the first event, 18 of 20 patients (90%) with a thrombophilia received oral anticoagulation. Before closure, patients who had a thrombophilia also had a higher rate of recurrences than patients who did not (p <0.0001), despite a similar follow-up (p = 0.14) and regardless of shunt entity (p = 0.59), presence of an atrial septal aneurysm (p = 0.98), and a prevalence of cardiovascular risk factors (p = 0.44). PFO closure was successful in all patients. Five patients (8%) had a residual shunt at 6 months. At 20 +/- 11 months after PFO closure, 3 recurrent events occurred (4%), and the recurrence rate was similar in patients who did and those who did not have a thrombophilia (p = 0.25). Thus, in patients who have a cryptogenic stroke, the association of a PFO with a thrombophilia significantly increases the risk of recurrences. Thus, transcatheter PFO closure is effective for preventing recurrences in patients who have a thrombophilia.

[Juvenile ischemic brain infarction. Clinical aspects, etiology spectrum, diagnosis and therapy]

Ischemic stroke in the young (age: 18-45 years) constitutes a diagnostic and therapeutic challenge. A broad spectrum of potential causes of juvenile strokes exists. Above all, nonatherosclerotic arteriopathies with dissections as their main proponent, paradoxical embolism, and thrombophilias have to be considered. Transient brief episodes with neurological deficits are difficult to discriminate from migrainous aura, epileptic seizure, psychogenic disorder. Therefore, the diagnostic work-up of juvenile stroke patients usually exceeds the amount of compulsory tests recommended in official guidelines. Various therapeutic modalities are not based on randomized large-scale studies and have to be selected on an individual basis. Despite good compliance, the annual risk of stroke recurrence is 2-3% and 1% for myocardial infarction.

Age as a determinant of adverse events in medically treated cryptogenic stroke patients with patent foramen ovale

BACKGROUND AND PURPOSE

Patent foramen ovale (PFO) is associated with cryptogenic stroke. There is no study that assessed the effect of age on adverse event rates in cryptogenic stroke patients with PFO. The purpose of this retrospective analysis from PFO in Cryptogenic Stroke Study (PICSS) database was to assess the effect of age on the risk of adverse events in medically treated cryptogenic stroke patients with PFO.

METHODS

250 cryptogenic stroke patients from PICSS were followed-up for 24 months, with death and recurrent ischemic stroke as primary endpoints. Hazard ratios were calculated for determination of relative risk in cryptogenic stroke patients with and without PFO in 3 age groups (younger than 55, 55 to 64, and 65 years or older).

RESULTS

Among the 2 younger age groups, the presence of PFO did not significantly affect the risk of adverse events (P=0.15; hazard ratio=0.21; 95% CI, 0.02 to 1.78; 2-year event rates, 2.0% versus 9.3%; and P=0.70; hazard ratio=0.72; 95% CI, 0.14 to 3.73; 2-year event rates, 10.0% versus 13.9%). However, in those aged 65 years or older, the risk of adverse events was significantly higher in the patients with PFO (P=0.01; hazard ratio=3.21; 95% CI, 1.33 to 7.75; 2-year event rates 37.9% versus 14.5%).

CONCLUSIONS

In this exploratory analysis, the presence of PFO in the younger cryptogenic stroke patients did not increase the risk of adverse events. However, in the older patients, PFO significantly increased the risk of adverse events.

Synergistic effect of apolipoprotein E polymorphisms and cigarette smoking on risk of ischemic stroke in young adults

BACKGROUND AND PURPOSE

The effect of apolipoprotein E (APOE) polymorphisms on stroke risk may be influenced by the coexistence of modifiable predisposing conditions. We explored the interactions of APOE genotypes and conventional risk factors in a case-control study of young adults with cerebral infarct.

METHODS

We analyzed 124 consecutive patients (age, 34.7+/-7.3 years) and 147 age- and sex-matched controls. APOE genotypes were determined by restriction fragment-length polymorphism analysis.

RESULTS

The prevalence of the epsilon4 allele and epsilon34 genotype was slightly higher in cases than in controls (0.125 versus 0.071 and 0.242 versus 0.136, respectively). Carriers of the epsilon34 genotype and epsilon4 allele were associated with an increased risk of stroke on multivariate analysis compared with the epsilon33 genotype and non-epsilon4 carriers, respectively (odds ratio [OR], 2.29; 95% confidence interval [CI], 1.10 to 4.76; and OR, 2.27; 95% CI, 1.13 to 4.56). ORs for stroke were 2.99 (95% CI, 1.64 to 5.45), 2.69 (95% CI, 1.25 to 5.77), and 5.39 (95% CI, 1.59 to 18.30) for smokers with the epsilon33 genotype, nonsmokers with the epsilon34 genotype, and smokers with the epsilon34 genotype, respectively, compared with nonsmokers with the epsilon33 genotype. Similar results were obtained when epsilon4 carriers and non-epsilon4 carriers were compared in the same interaction model. No significant interaction between APOE and hypertension was found.

CONCLUSIONS

In young adults, the APOE epsilon4 allele and cigarette smoking act synergistically, increasing an individual's propensity to have a cerebral ischemic event. This finding may help in determining an individual's predisposition to stroke and more targeted preventive interventions.

Increased Pelvic Vein Thrombi in Cryptogenic Stroke

BACKGROUND AND PURPOSE

Cryptogenic stroke is associated with an increased prevalence of patent foramen ovale. The Paradoxical Emboli From Large Veins in Ischemic Stroke (PELVIS) study hypothesized that patients with cryptogenic stroke have an increased prevalence of pelvic deep venous thrombosis (DVT).

METHODS

At 5 sites, patients 18 to 60 years of age received an MRI venogram (MRV) of the pelvis within 72 hours of new symptom onset. Clinical data were then determined. Radiologists blinded to clinical data later read the scans.

RESULTS

The 95 patients who met entry criteria were scanned. Their mean+/-SD age was 46+/-10 years, and time from stroke onset to pelvic MRV scan was 49+/-16 hours. Compared with those with stroke of determined origin (n=49), patients with cryptogenic stroke (n=46) were significantly younger, had a higher prevalence of patent foramen ovale (61% versus 19%), and had less atherosclerosis risk factors. Cryptogenic patients had more MRV scans with a high probability for pelvic DVT (20%) than patients with stroke of determined origin (4%, P<0.03), with most having an appearance of a chronic DVT.

CONCLUSIONS

In this study of young stroke patients evaluated early after stroke, patients with cryptogenic stroke showed differences in several clinical features compared with patients with stroke of determined origin, including increased prevalence of pelvic DVT. The results require confirmation but suggest that paradoxical embolus from the pelvic veins may be the cause of stroke in a subset of patients classified as having cryptogenic stroke.

Race-ethnic differences in patent foramen ovale, atrial septal aneurysm, and right atrial anatomy among ischemic stroke patients

BACKGROUND AND PURPOSE

Stroke remains a substantial cause of mortality and morbidity in the United States. Racial differences in stroke incidence and mortality persist with well-known excesses among blacks. Information on stroke among Hispanics is limited. In particular, little is known about whether patent foramen ovale (PFO), atrial septal aneurysm (ASA), and other atrial anomalies associated with cryptogenic stroke differ among minority populations.

METHODS

As a part of the PFO in Cryptogenic Stroke Study, transesophageal echocardiography was performed in a cohort of 630 ischemic stroke patients (mean age, 59+/-12 years; 44% women; 45% whites, 35% blacks, 17% Hispanics, 3% other). The prevalences of PFO, ASA, and right atrial (RA) anatomy favoring paradoxical embolization were compared among race-ethnic groups. Statistical analyses used analysis of variance for continuous variables and logistic regression for dichotomous variables with adjustments for age and sex.

RESULTS

Age- and sex-adjusted prevalences of PFO and ASA were similar across race-ethnic subgroups. However, large PFO was significantly less prevalent among blacks than among whites (odds ratio, 0.47; 95% confidence interval, 0.24 to 0.91; P=0.02). RA anatomy favoring paradoxical embolization was also significantly less prevalent among blacks compared with whites (odds ratio, 0.62; 95% confidence interval, 0.43 to 0.91; P=0.01). There were no significant differences in prevalence between whites and Hispanics.

CONCLUSIONS

Although the frequency of PFO did not vary among race-ethnic groups, a large PFO and RA anatomy favoring paradoxical embolization were significantly more prevalent among whites and Hispanics compared with blacks. These may be relatively more important risk factors for stroke among whites and Hispanics than among blacks.

Role of transesophageal echocardiography in the evaluation of patients with stroke

This review article summarizes recent advances in the care of patients presenting with neurologic events, in which transesophageal echocardiography plays an important role in diagnosis, prognosis, and treatment. New research on the use of transesophageal echocardiography in patients with stroke and atrial fibrillation is discussed, including left atrial clot formation, maintenance of sinus rhythm after cardioversion, and techniques of left atrial appendage occlusion. A discussion of developments in the diagnosis and management of thoracic aortic plaque follows. The association of patent foramen ovale and atrial septal aneurysm with stroke is outlined, and possible reasons for this association are discussed. Recent literature on the use of percutaneous closure devices for patent foramen ovale is reviewed.

Screening for hypercoagulable syndromes following stroke

Patients with ischemic stroke of unclear etiology are often screened for hypercoagulable syndromes or thrombophilias. These have been recognized to cause venous thrombosis, and include hereditary deficiencies of coagulation factors, genetic mutations, or acquired disorders. However, the majority of coagulation disorders are only rarely associated with ischemic stroke. The tests most commonly used to screen for thrombophilias comprise a complex array of assays that may be unreliable in various settings, including acute thrombosis, inflammation, and uses of medications such as anticoagulants. The diagnostic yield of thrombophilia tests in unselected stroke patients is very low, but may improve with careful selection of younger patients who have an otherwise undetermined cause of stroke or a history of venous thrombosis or multiple miscarriages. Various strategies have been developed that can guide the selection of patients (based on specific characteristics) and tests in the evaluation of thrombophilias. Although the diagnosis of thrombophilia aids in the potential explanation of stroke etiology, the best regimen for secondary prevention treatment for the majority of thrombophilias is still unknown.