Differential characteristics, stroke recurrence, and predictors of covert atrial fibrillation of embolic strokes of undetermined source

P-wave indices and left atrial mechanics as predictors of atrial cardiopathy in embolic stroke of undetermined source

Recent research has shed light on the culpability of LA (left atrial) abnormality, in the form of atrial cardiopathy, as an independent risk factor for the development of atrial fibrillation, LA thrombus and subsequent stroke. The aim of this study was to measure LA electromechanical dissociation (EMD), LA volumes, P-wave dispersion (PWD) and P-wave terminal force in V1 (PTFV1) as markers of atrial cardiopathy in patients with ESUS (embolic stroke of undetermined source), to determine whether atrial cardiopathy is an integral part in the causal pathway of ESUS. 28 patients presenting with ischemic stroke and fulfilling the criteria for ESUS were enrolled into this cross-sectional, observational study along with a control group of 28 age- and gender-matched apparently healthy individuals. On ECG, PWD and PTFV1 were measured. On echocardiography, LA EMD and LA volumes were recorded. Increased PWD (34.14 ± 9.89 ms vs. 27.32 ± 8.95 ms; p = 0.01), atrial EMD (73.32 ± 16.31 ms vs. 63.63 ± 13.59 ms; p = 0.02) and LA volumes were observed in patients with ESUS as compared to controls. A significant correlation was also found between these parameters (p < 0.01). According to the results of our study, PWD, atrial EMD and LA volumes may be novel predictors for ESUS. Our results support the notion that atrial cardiopathy is a distinct mechanism of thrombosis in ESUS patients. Further research is required to clarify its function in the causation of stroke, ESUS in particular.

Soluble suppression of tumorigenicity 2 associated with atrial fibrillation detected after stroke: A retrospective study

Background

The soluble suppression of tumorigenicity 2 (sST2) is closely associated with stroke and atrial fibrillation (AF). However, no studies on sST2 and AF detected after stroke (AFDAS) have been reported. This study investigated the correlation between sST2 and AFDAS.

Methods

This was a single-center, retrospective, clinical observational study. Patients diagnosed with a transient ischemic attack (TIA) or acute ischemic stroke were enrolled, and all patients underwent sST2 detection and electrocardiogram (ECG) or Holter monitoring for at least 24 h.

Results

In total, 970 patients were enrolled, including 72 (7.4 %) with AFDAS. Multivariate analysis showed that age (OR 1.078; 95 % CI, 1.050-1.107; p < 0.001), heart rate (HR) (OR 1.025; 95 % CI, 1.007-1.044; p = 0.007), national institutes of health stroke scale (NIHSS) score (OR 1.089; 95 % CI, 1.029-1.152; p = 0.003), high sensitivity C-reactive protein (hs-CRP) (OR 1.006; 95 % CI, 1.002-1.009; p = 0.001), and sST2 (OR 1.018; 95 % CI, 1.010-1.026; p < 0.001) were independent risk factors of AFDAS. The areas under the curve (AUCs) for age, HR, sST2, hs-CRP, and NIHSS were 0.731, 0.599, 0.815, 0.664, and 0.700, respectively. The conventional model included age, HR, NIHSS score, and hs-CRP level based on multivariate results. After adding sST2 to the model, the model's performance in predicting AFDAS increased significantly.

Conclusion

Higher sST2 levels were associated with the occurrence of AFDAS. Thus, sST2 can improve the risk model for AFDAS.

Molecular biomarkers predicting newly detected atrial fibrillation after ischaemic stroke or TIA: A systematic review

Background:

Several molecular biomarkers are available that predict newly detected atrial fibrillation (NDAF). We aimed to identify such biomarkers that predict NDAF after an Ischaemic stroke (IS)/Transient Ischaemic Attack (TIA) and evaluate their performance.

Methods:

A systematic review was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies of patients with IS, TIA, or both, who underwent ECG monitoring for ⩾24 h, which reported molecular biomarkers and frequency of NDAF after electronic searches of multiple databases were included.

Results:

Twenty-one studies (76% IS, 24% IS and TIA) involving 4640 patients were included. Twelve biomarkers were identified, with cardiac biomarkers evaluated in the majority (75%) of patients. Performance measures were inconsistently reported. Among cohorts selecting high-risk individuals (12 studies), the most studied biomarkers were N-Terminal-Pro Brain Natriuretic Peptide (NT-ProBNP, five studies; C-statistics reported by three studies, 0.69–0.88) and Brain Natriuretic Peptide (BNP, two studies; C-statistics reported in two studies, 0.68–0.77). Among unselected cohorts (nine studies), the most studied biomarker was BNP (six studies; C-statistics reported in five studies, 0.75–0.88). Only BNP was externally validated (two studies) but using different thresholds to categorise risk of NDAF.

Conclusion:

Cardiac biomarkers appear to have modest to good discrimination for predicting NDAF, although most analyses were limited by small, heterogeneous study populations. Their clinical utility should be explored further, and this review supports the need to assess the role of molecular biomarkers in large prospective studies with standardised selection criteria, definition of clinically significant NDAF and laboratory assays.

Risk of recurrent ischemic stroke in young cryptogenic patients with embolic stroke of undetermined source

INTRODUCTION

Elderly cryptogenic ischemic stroke (IS) patients with embolic stroke of undetermined source (ESUS) have a high risk of recurrent IS (RIS) compared to other stroke subtypes. In young ESUS patients, different sources of embolism may be a cause and the risk of RIS remains not enough established. The aim was to assess and compare risk of RIS between ESUS and non ESUS patients <50 years.

METHODS

The study set consisted of young acute IS patients <50 years enrolled in the prospective HISTORY (Heart and Ischemic STrOke Relationship studY) study registered on ClinicalTrials.gov (NCT01541163). In all analyzed patients, the brain ischemia was confirmed on CT or MRI. All patients underwent identical diagnostic protocol including TEE and long-term ECG-Holter. Cause of IS was assessed according to the ASCOD classification.

RESULTS

Of 320 enrolled patients <50 years, 219 (68.4%) were identified as cryptogenic (119 males, mean age 41.4 ± 7.2 years) and 122 (38.1%) patients fulfilled the ESUS criteria. During the follow-up with a median of 34 months, three (2.5%) ESUS and 5 (5.2%) non-ESUS patients suffered from RIS (p = .471). One-year risk of RIS was 0.008 (95% CI: 0-0.025) for ESUS and 0.036 (95% CI: 0-0.076) for non-ESUS patients (p = .262).

CONCLUSION

The risk of RIS was very low in ESUS patients and did not differ from those with non-ESUS. Our finding may indicate that antiplatelet therapy can be effective in the secondary prevention in young ESUS patients if high-risk sources of embolization are excluded extensively.

Markers of endothelial pathology to support detection of atrial fibrillation in embolic stroke of undetermined source

A relevant part of embolic strokes of undetermined source (ESUS) is assumed to be cardiogenic. As shown previously, certain biomarkers of endothelial pathology are related to atrial fibrillation (AF). In this long-term follow-up study, we aimed to investigate whether these biomarkers are associated with subsequently diagnosed AF and with atrial cardiopathy. In 98 patients who suffered ischemic stroke of known and unknown origin L-arginine, Asymmetric (ADMA) and Symmetric Dimethylarginine (SDMA) have been measured on follow-up at least one year after index stroke. Stroke-diagnostics were available for all patients, including carotid Intima-Media-Thickness (CIMT) and comprehensive echocardiography studies. CIMT was larger in AF- compared with ESUS-patients (P < 0.001), independently from CHA2DS2VASC in the regression analysis (P = 0.004). SDMA-values were stable over time (P < 0.001; r = 0.788), whereas for ADMA moderate correlation with the initial values could be found (P = 0.007; r = 0.356). According to Kaplan-Meier-analyses, AF-detection rates were associated with CIMT (P = 0.003) and SDMA (P < 0.001). SDMA correlated with left atrial volume-index within the whole collective (P = 0.003, r = 0.322) and within the ESUS-subgroup (P = 0.003; r = 0.446). These associations were independent from CHA2DS2VASC and renal function in the regression analysis (P = 0.02 and P = 0.005, respectively). In conclusion, these results highlight SDMA and CIMT as potential markers of atrial cardiopathy and AF in ESUS-patients.

A tool to identify patients with embolic stroke of undetermined source at high recurrence risk

OBJECTIVE

A tool to stratify the risk of stroke recurrence in patients with embolic stroke of undetermined source (ESUS) could be useful in research and clinical practice. We aimed to determine whether a score can be developed and externally validated for the identification of patients with ESUS at high risk for stroke recurrence.

METHODS

We pooled the data of all consecutive patients with ESUS from 11 prospective stroke registries. We performed multivariable Cox regression analysis to identify predictors of stroke recurrence. Based on the coefficient of each covariate of the fitted multivariable model, we generated an integer-based point scoring system. We validated the score externally assessing its discrimination and calibration.

RESULTS

In 3 registries (884 patients) that were used as the derivation cohort, age, leukoaraiosis, and multiterritorial infarct were identified as independent predictors of stroke recurrence and were included in the final score, which assigns 1 point per every decade after 35 years of age, 2 points for leukoaraiosis, and 3 points for multiterritorial infarcts (acute or old nonlacunar). The rate of stroke recurrence was 2.1 per 100 patient-years (95% confidence interval [CI] 1.44-3.06) in patients with a score of 0-4 (low risk), 3.74 (95% CI 2.77-5.04) in patients with a score of 5-6 (intermediate risk), and 8.23 (95% CI 5.99-11.3) in patients with a score of 7-12 (high risk). Compared to low-risk patients, the risk of stroke recurrence was significantly higher in intermediate-risk (hazard ratio [HR] 1.78, 95% CI 1.1-2.88) and high-risk patients (HR 4.67, 95% CI 2.83-7.7). The score was well-calibrated in both derivation and external validation cohorts (8 registries, 820 patients) (Hosmer-Lemeshow test χ²: 12.1 [p = 0.357] and χ²: 21.7 [p = 0.753], respectively). The area under the curve of the score was 0.63 (95% CI 0.58-0.68) and 0.60 (95% CI 0.54-0.66), respectively.

CONCLUSIONS

The proposed score can assist in the identification of patients with ESUS at high risk for stroke recurrence.

Renal Function and Risk Stratification of Patients With Embolic Stroke of Undetermined Source

Background and Purpose- We aimed to assess if renal function can aid in risk stratification for ischemic stroke or transient ischemic attack (TIA) recurrence and death in patients with embolic stroke of undetermined source (ESUS). Methods- We pooled 12 ESUS datasets from Europe and America. Renal function was evaluated using the estimated glomerular filtration rate (eGFR) and analyzed in continuous, binary, and categorical way. Cox-regression analyses assessed if renal function was independently associated with the risk for ischemic stroke/TIA recurrence and death. The Kaplan-Meier product limit method estimated the cumulative probability of ischemic stroke/TIA recurrence and death. Results- In 1530 patients with ESUS followed for 3260 patient-years, there were 237 recurrences (15.9%) and 201 deaths (13.4%), corresponding to 7.3 ischemic stroke/TIA recurrences and 5.6 deaths per 100 patient-years, respectively. Renal function was not associated with the risk for ischemic stroke/TIA recurrence when forced into the final multivariate model, regardless if it was analyzed as continuous (hazard ratio, 1.00; 95% CI, 0.99-1.00 for every 1 mL/min), binary (hazard ratio, 1.27; 95% CI, 0.87-1.73) or categorical covariate (likelihood-ratio test 2.59, P=0.63 for stroke recurrence). The probability of ischemic stroke/TIA recurrence across stages of renal function was 11.9% for eGFR ≥90, 16.6% for eGFR 60-89, 21.7% for eGFR 45-59, 19.2% for eGFR 30-44, and 24.9% for eGFR <30 (likelihood-ratio test 2.59, P=0.63). The results were similar for the outcome of death. Conclusions- The present study is the largest pooled individual patient-level ESUS dataset, and does not provide evidence that renal function can be used to stratify the risk of ischemic stroke/TIA recurrence or death in patients with ESUS.

Features of Patients Aged 80 Years or Older with Embolic Stroke of Undetermined Source

BACKGROUND

Embolic stroke of undetermined source has not been thoroughly investigated in older patients. In this study, we investigated the features of this condition in patients greater than or equal to 80 years of age.

METHODS

All patients with acute ischemic stroke in our hospital underwent diffusion-weighted imaging, magnetic resonance angiography, T2-weighted imaging, and fluid-attenuated inversion recovery sequence imaging. Embolic stroke of undetermined source was defined as a radiologically confirmed nonlacunar brain infarct on diffusion-weighted imaging without (1) extracranial or intracranial atherosclerosis causing greater than or equal to 50% luminal stenosis in arteries supplying the ischemic area, (2) major-risk cardioembolic source, and (3) any other specific cause of stroke. We retrospectively identified consecutive patients hospitalized for acute ischemic stroke who met the embolic stroke of undetermined source diagnostic criteria and investigated patients' baseline and diagnostic findings.

RESULTS

We divided 122 consecutive embolic stroke of undetermined source patients (median age: 73 years; 49 men, 73 women) into 2 groups by age at admission. Patients aged greater than or equal to 80 years had higher D-dimer and brain natriuretic peptide levels, more frequent premature atrial complexes/day in 24-hour Holter electrocardiography, and thicker maximum intima media thickness on ultrasound compared with patients aged less than 80 years (P < .05, U test).

CONCLUSIONS

Our results suggest that high admission D-dimer and brain natriuretic peptide levels are associated with age of onset in patients with embolic stroke of undetermined source. Patients aged greater than or equal to 80 years tended to have more frequent premature atrial complexes and thicker maximum intima media thickness compared with patients aged less than 80 years.

Atrial cardiopathy in patients with embolic strokes of unknown source and other stroke etiologies

Objective

To investigate the prevalence and clinical determinants of atrial cardiopathy in patients with embolic stroke of unknown source (ESUS) and compare with other established stroke etiologies.

Methods

In a cross-sectional study of 846 consecutive patients with ischemic stroke, we compared the prevalence of atrial cardiopathy (defined by p-wave terminal force in V1 >5,000 µV·ms or severe left atrial enlargement) between ESUS patients and patients with large artery atherosclerosis (LAA) and small vessel disease (SVD) strokes. Baseline characteristics were also compared between ESUS and cardioembolic (CE) patients.

Results

Of all, 158 (19%) patients met ESUS diagnostic criteria, while others were classified into LAA (n = 224, 26%), SVD (n = 154, 18%), and CE (n = 310, 37%). The prevalence of atrial cardiopathy was higher in ESUS patients compared to noncardioembolic stroke patients (26.6% vs 12.1% in LAA vs 16.9% in SVD; p = 0.001). ESUS patients were younger, were less hypertensive, and had higher cholesterol and low-density lipoprotein levels, but also had less left ventricular or atrial abnormalities when compared to CE patients.

Conclusion

The prevalence of atrial cardiopathy was high in ESUS patients compared with patients with nonembolic strokes. Interestingly, ESUS patients were also clinically different from CE patients. While the presence of atrial cardiopathy may reflect a unique mechanism of thromboembolism in ESUS patients, it is still unclear if they may benefit from anticoagulation, or if the presence of atrial cardiopathy in this population could serve as a risk-stratifying marker for stroke recurrence. Further efforts are necessary to provide better characterization of the ESUS population in order to develop better stroke preventive strategies.

Embolic strokes of undetermined source in a cohort of Polish stroke patients

We aimed to provide a descriptive analysis of embolic stroke of undetermined etiology (ESUS) population based on a long-term prospective stroke registry. We retrospectively analyzed data collected in a detailed registry regarding consecutive patients admitted for first-ever ischemic stroke (IS) between January 2001 and December 2015. We used Org 10172 in Acute Stroke Treatment classification supplemented with ESUS criteria proposed by the Cryptogenic Stroke/ESUS International Working Group. Within the ESUS group, we additionally compared patients ≤ 60 and > 60 years of age. During the study period, there was a total of 3008 (1615 females and 1393 males) admissions of first-ever strokes. The most frequent cause was undetermined (38.7%), followed by cardioembolic (27.7%), large artery atherosclerosis (18.2%), small vessel disease (11.9%), and other determined (3.6%). We identified 326 patients as ESUS, which accounted for 10.8% of all strokes and 28% of strokes of undetermined etiology. ESUS patients were the youngest. Compared to all types of stroke but for those with small vessel disease, ESUS patients were most often independent before stroke and had the least severe neurological deficit at admission and the best outcome at discharge. ESUS patients ≤ 60 years were more frequently independent at discharge than ESUS patients > 60 years. Approximately 11% of patients from our registry met ESUS criteria. ESUS patients were younger when compared to all other stroke etiologies, suffered less severe strokes, and had more favorable outcome at discharge than other groups except for those with small vessel disease strokes.