Newly detected atrial fibrillation is associated with cortex-involved ischemic stroke

Imaging features for the identification of atrial fibrillation in cryptogenic stroke patients

BACKGROUND

Whether specific imaging aspects can be used to identify cryptogenic stroke (CS) patients with high risk of underlying atrial fibrillation (AF) remains unclear. The purpose of this study was to evaluate brain-imaging features in CS patients and their utility as AF predictors.

METHODS

The Nordic Atrial Fibrillation and Stroke study was a prospective observational study of CS and transient ischemic attack patients undergoing 12-month cardiac-rhythm monitoring, biomarker and clinical assessments. In this imaging sub-study, brain magnetic resonance imaging and computed tomography scans from 106 patients were assessed for acute and chronic ischemic lesions in relation to AF occurrence and included in a score to predict AF. Receiver operating characteristics (ROC) curve was used to evaluate the discriminative ability of the score and for its dichotomization for predictive model.

RESULTS

Age, periventricular white-matter hyperintensities (PVWMH), acute lesion size, and vessel occlusion were significantly associated with AF. Acute and chronic cortical infarcts as well as chronic cerebellar infarcts were numerically more frequent in the AF group than the non-AF group. A score consisting of six features (0-6 points) was proposed (age ≥ 65 years, chronic cortical or cerebellar lesions, acute cortical lesions, PVWMH ≥ 2 in Fazekas scale, vessel occlusion, and acute lesion size ≥ 10 mm). Area under ROC curve was 0.735 and a score of ≥ 3 points was a predictor of AF.

CONCLUSIONS

The suggested score was shown to identify CS patients with an increased risk of underlying AF.

Association of stroke lesion shape with newly detected atrial fibrillation – Results from the MonDAFIS study

Paroxysmal Atrial fibrillation (AF) is often clinically silent and may be missed by the usual diagnostic workup after ischemic stroke. We aimed to determine whether shape characteristics of ischemic stroke lesions can be used to predict AF in stroke patients without known AF at baseline. Lesion shape quantification on brain MRI was performed in selected patients from the intervention arm of the Impact of standardized MONitoring for Detection of Atrial Fibrillation in Ischemic Stroke (MonDAFIS) study, which included patients with ischemic stroke or TIA without prior AF. Multiple morphologic parameters were calculated based on lesion segmentation in acute brain MRI data. Multivariate logistic models were used to test the association of lesion morphology, clinical parameters, and AF. A stepwise elimination regression was conducted to identify the most important variables. A total of 755 patients were included. Patients with AF detected within 2 years after stroke (n = 86) had a larger overall oriented bounding box (OBB) volume (p = 0.003) and a higher number of brain lesion components (p = 0.008) than patients without AF. In the multivariate model, OBB volume (OR 1.72, 95%CI 1.29–2.35, p < 0.001), age (OR 2.13, 95%CI 1.52–3.06, p < 0.001), and female sex (OR 2.45, 95%CI 1.41–4.31, p = 0.002) were independently associated with detected AF. Ischemic lesions in patients with detected AF after stroke presented with a more dispersed infarct pattern and a higher number of lesion components. Together with clinical characteristics, these lesion shape characteristics may help in guiding prolonged cardiac monitoring after stroke.

Differences between Atrial Fibrillation Detected before and after Stroke and TIA: A Systematic Review and Meta-Analysis

BACKGROUND

Preliminary evidence suggests that patients with atrial fibrillation (AF) detected after stroke (AFDAS) may have a lower prevalence of cardiovascular comorbidities and lower risk of stroke recurrence than AF known before stroke (KAF).

OBJECTIVE

We performed a systematic search and meta-analysis to compare the characteristics of AFDAS and KAF.

METHODS

We searched PubMed, Scopus, and EMBASE for articles reporting differences between AFDAS and KAF until June 30, 2021. We performed random- or fixed-effects meta-analyses to evaluate differences between AFDAS and KAF in demographic factors, vascular risk factors, prevalent vascular comorbidities, structural heart disease, stroke severity, insular cortex involvement, stroke recurrence, and death.

RESULTS

In 21 studies including 22,566 patients with ischemic stroke or transient ischemic attack, the prevalence of coronary artery disease, congestive heart failure, prior myocardial infarction, and a history of cerebrovascular events was significantly lower in AFDAS than KAF. Left atrial size was smaller, and left ventricular ejection fraction was higher in AFDAS than KAF. The risk of recurrent stroke was 26% lower in AFDAS than in KAF. There were no differences in age, sex, stroke severity, or death rates between AFDAS and KAF. There were not enough studies to report differences in insular cortex involvement between AF types.

CONCLUSIONS

We found significant differences in the prevalence of vascular comorbidities, structural heart disease, and stroke recurrence rates between AFDAS and KAF, suggesting that they constitute different clinical entities within the AF spectrum. PROSPERO registration number is CRD42020202622.

Brain Infarction MRI Pattern in Stroke Patients with Intracardiac Thrombus

BACKGROUND

Acute infarction patterns have been described in cardioembolic stroke, mainly with atrial fibrillation (AF) or patent foramen ovale. We aimed to analyse acute infarction magnetic resonance imaging (MRI) characteristics in stroke patients with intracardiac thrombus (ICT) compared with stroke patients with AF.

METHODS

We performed a retrospective study analysing brain MRI scans of consecutive acute symptomatic cardioembolic infarction patients associated with ICT or AF who were recruited and registered in the stroke database between June 2018 and November 2019. Diffusion-weighted imaging performed within 1 week after symptom onset, intra-/extracranial vessel imaging, echocardiography, and ≥24-h ECG monitoring were required for inclusion. Baseline, biological, and echocardiography characteristics were assessed. Analysed MRI characteristics were infarction location (anterior/middle/posterior cerebral artery territory; anterior/posterior/mixed anterior-posterior circulation; multiterritorial infarction; brainstem; cerebellum; small cortical cerebellar infarctions [SCCIs] or non-SCCI; cortical/subcortical/cortico-subcortical), lesion number, subcortical lesion size (> or <15 mm), and total infarction volume.

RESULTS

We included 28 ICT and 94 AF patients presenting with acute stroke. ICT patients were younger (median age 66 vs. 81 years, p < 0.001), more frequently male (79 vs. 47%, p = 0.003), and smokers (39 vs. 17%, p = 0.013), had more frequent history of diabetes (36 vs. 18%, p = 0.049) and ischaemic heart disease (57 vs. 21%, p < 0.001), and had lower HDL cholesterol levels (0.39 vs. 0.53 g/L, p < 0.001). On MRI, SCCI was more frequent in the ICT group (25 vs. 5%, p = 0.006) in the absence of other differences in infarction localisation, number, size, or volume on MRI. On multivariate analysis, younger age (p < 0.001), history of ischaemic heart disease (p < 0.001), and low HDL cholesterol levels (p = 0.01) were significantly associated with ICT. Results approaching statistical significance were observed for SCCI (more frequent in the ICT group, p = 0.053) and non-SCCI (more frequent in the AF group, p = 0.053) on MRI.

CONCLUSIONS

ICT-related stroke is associated with acute SCCI presence on MRI. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT04456309.

Potential Therapies for Cerebral Edema After Ischemic Stroke: A Mini Review

Stroke is the leading cause of global mortality and disability. Cerebral edema and intracranial hypertension are common complications of cerebral infarction and the major causes of mortality. The formation of cerebral edema includes three stages (cytotoxic edema, ionic edema, and vasogenic edema), which involve multiple proteins and ion channels. A range of therapeutic agents that successfully target cerebral edema have been developed in animal studies, some of which have been assessed in clinical trials. Herein, we review the mechanisms of cerebral edema and the research progress of anti-edema therapies for use after ischemic stroke.