Diagnostic And Prognostic Value Of Left Atrial Function In Identification Of Cardioembolism And Prediction Of Outcomes In Patients With Cryptogenic Stroke

Altered left atrial metrics in patients with cryptogenic stroke: A systematic review and meta-analysis

BACKGROUND

There is no defined cause for cryptogenic stroke/embolic stroke of undetermined source (CS-ESUS). As atrial fibrillation (AF) develops in a significant proportion of these patients, it has been suggested that left atrial (LA) myopathy may predispose to CS-ESUS. We investigated alterations in echocardiographic measures of LA size and function in patients with CS-ESUS.

METHODS

A systematic literature review and meta-analysis was performed. PubMed, EMBASE, Cochrane Library, Web of Science and SCOPUS were searched for articles published between 1 January 1990 and 10 February 2023. All observational studies of adult CS-ESUS patients with LA volume or function measurements performed by transthoracic echocardiogram were included. Individual random effects meta-analyses were performed on LA measurements in the CS-ESUS patients using subgroup analysis of comparator groups.

RESULTS

We included 29 articles with 3927 CS-ESUS patients. Analysis of weighted mean differences showed CS-ESUS patients had altered LA structure and function parameters, with a larger maximum indexed LA volume, reduced LA emptying fraction and/or LA reservoir strain, compared to healthy controls and noncardioembolic stroke patients. Conversely, CS-ESUS patients had a smaller left atrium with better function, compared to cardioembolic stroke patients and CS-ESUS patients who subsequently developed atrial fibrillation.

CONCLUSIONS

LA volume and function are altered in CS-ESUS patients compared to healthy controls and other stroke aetiologies. An underlying atrial myopathy in a subset of CS-ESUS patients may be involved in both thrombogenesis and dysrhythmia (specifically AF). While LA functional assessment is not currently recommended following stroke, it may offer an opportunity for recurrent stroke risk stratification.

Distribution of atrial cardiomyopathy markers and association with atrial fibrillation detected after ischaemic stroke in the SAFAS study

BACKGROUND

Atrial cardiomyopathy (AC) is an emerging concept explaining the pathophysiology of cardioembolic strokes in absence of atrial fibrillation (AF). A definition based on the presence of electrical abnormality (P-wave terminal force in lead V1 (PTFV1) >5000 µV×ms), N-Terminal pro-B-type natriuretic peptide (NT pro BNP) >250 pg/mL and/or indexed left atrial diameter (LADI) >3 cm/m² is currently tested in the ARCADIA (AtRial Cardiopathy and Antithrombotic Drugs In prevention After cryptogenic stroke) trial. We set out to estimate the prevalence of AC as defined in the ARCADIA trial, its determinants and its association with AF detected after stroke (AFDAS).

METHODS

Stepwise screening for silent Atrial Fibrillation After Stroke (SAFAS) study prospectively included 240 ischaemic stroke patients. AC markers were complete for 192 of them and 9 were not included in this analysis because AF had been diagnosed on admission.

RESULTS

A total of 183 patients were analysed, of whom 57% (104 patients) met the AC criteria (79 NT-proBNP, 47 PTFV1, 4 LADI). In the multivariate logistic regression, C reactive protein >3 mg/L (OR (95% CI) 2.60 (1.30 to 5.21), p=0.007) and age (OR (95% CI) 1.07 (1.04 to 1.10), p<0.001) were found to be independently associated with AC. After 6 months of follow-up, AFDAS was detected in 33% of AC patients and in 14% of the remaining ones (p=0.003). However, AC was not independently associated with AFDAS, contrary to left atrial volume index (>34 mL/m2, OR 2.35 (CI 1.09 to 5.06) p=0029).

CONCLUSION

AC as defined in ARCADIA is mostly based on NT pro BNP elevation (76% of patients) and is associated with age and inflammation. Moreover, AC was not independently associated with AFDAS at follow-up. The ARCADIA trial, which compares aspirin to apixaban in patients with embolic strokes of undetermined source with AC markers and must, therefore be analysed in the light of these limitations.

TRIAL REGISTRATION NUMBER

NCT03570060.

Prognostic value of left atrial strain in patients with tetralogy of fallot

To demonstrate prognostic utility of left atrial strain (LAS) in adult patients with repaired Tetralogy of Fallot (rTOF). Adults patients with rTOF were prospectively enrolled in this study between years 2011 and 2015. Left atrium (LA) phasic functions were assessed using 2D speckle tracking echocardiography. Association of LA strain (LAS) with primary (any cardiovascular event) and secondary (death, heart failure or arrhythmia) composite endpoints was assessed using Cox regression analysis. Hundred-and-twelve rTOF patients, in whom LAS was feasible and were in sinus rhythm, were included in the final analysis (age 33 ± 10 years, 68[61%] male). Median duration of follow-up was 8.6 [4.2-9.7] years in the study group. Primary composite endpoint was reached in 48 patients (mean event-free survival time: 7.2 [6.6-7.9] years), and secondary composite endpoint was reached in 22 patients (mean event-free survival time: 8.7 [8.1-9.2] years). LA reservoir strain (LAS-r) was defined as tertile groups (1st tertile < 33%, 2nd tertile = 33-44%, 3rd tertile > 44%). Decreasing tertiles of LAS-r was associated with primary and secondary composite endpoints in Kaplan-Meier analysis (p = 0.02 and 0.002, respectively). In univariable Cox-regression, both decreasing LAS-r and LAS-r tertiles were associated with primary and secondary composite endpoints. Adjusted by initial repair age and NT-proBNP quartiles, increased LAS-r was associated with significantly decreased occurrence of experiencing any events (HR = 0.97, CI 0.93-0.99, p < 0.001). Decreasing LAS-r was still associated with primary endpoint when adjusted by left atrium volume index (LAVImax) (HR = 0.96, CI 0.92-0.99, p = 0.01), left ventricle global longitudinal strain (HR = 0.96, CI 0.93-0.99, p < 0.001) or right ventricle free wall longitudinal strain (HR = 0.96, CI 0.93-0.99, p = 0.03). Assessment of LA mechanics with the use of STE has incremental utility in determination of mortality and morbidity in rTOF, and may be implemented in clinical practice.

Left atrial strain, embolic stroke of undetermined source, and atrial fibrillation detection

BACKGROUND

Atrial cardiopathy is a proposed mechanism of embolic stroke of undetermined source (ESUS). Left atrial (LA) strain may identify early atrial cardiopathy prior to structural changes. We aim to study the associations between LA strain, ESUS, and atrial fibrillation (AF) detection in ESUS.

METHODS

The study population included patients with ESUS and noncardioembolic (NCE) stroke presenting to the Rhode Island Hospital Stroke Center between January 2016 and June 2017 who underwent transthoracic echocardiography. Speckle tracking echocardiography (STE) was used to measure the three phases of LA strain (reservoir, conduit, and contractile). Binary logistic regression analysis was performed to determine the associations between LA strain and stroke subtype (ESUS vs. NCE) as well as follow-up detection of AF in ESUS patients.

RESULTS

We identified 656 patients, 307 with ESUS and 349 with NCE. In binary logistic regression, the lowest tertiles of LA reservoir (adjusted OR 1.944, 95% CI 1.266-2.986, p = .002), contractile (aOR 1.568, 95% CI 1.035-2.374, p = .034), and conduit strain (aOR 2.288, 95% CI 1.448-3.613, p = .001) were more likely to be significantly associated with ESUS compared to NCE stroke. Among all ESUS patients, the lowest tertiles of LA reservoir strain (OR 2.534, 95% CI 1.029-6.236, p = .043), contractile strain (OR 2.828, 95% CI 1.158-6.903, p = .022), and conduit strain (OR 2.614, 95% CI 1.003-6.815, p = .049) were significantly associated with subsequent detection of AF.

CONCLUSION

Reduced LA strain is associated with ESUS occurrence and AF detection in ESUS patients. Therefore, quantification of LA strain in ESUS patients may improve risk stratification and guide secondary prevention strategies.

Left Atrial Strain Predicts Stroke Recurrence and Death in Patients With Cryptogenic Stroke

Left atrial strain (LAS) has been widely studied as a predictor of atrial fibrillation (AF) after cryptogenic stroke (CS). However, the evidence about its prognostic role in terms of stroke recurrence and death in this setting remains scarce. A total of 92 consecutive patients with ischemic stroke or transient ischemic attack with ABCD2 scale ≥4 of unknown etiology were prospectively recruited. Echocardiography, including LAS was performed during admission. The primary outcome measure was the composite of stroke recurrence or death. The mean age was 77.5 ± 7.7, and 58% of patients were female. After a median follow up of 28 months, the primary outcome measure occurred in 15 patients (16%). The primary outcome was more frequent in patients with diabetes (53% vs 21%, p = 0.02), chronic kidney disease (33% vs 10%, p = 0.034), and a history of heart failure (13% vs 0%, p = 0.025). LAS reservoir (LASr) and LAS conduit (LAScd) were lower in patients developing the primary outcome (21% ± 7% vs 28.8% ± 11%, p = 0.017 and 7.7% ± 3.9% vs 13.7% ± 7%, p = 0.007, respectively). On multivariate analysis, LASr (hazard ratio 0.9, 95% confidence interval 0.85 to 0.99, p = 0.048) and diabetes (hazard ratio 3.3, 95% confidence interval 1.03 to 10.4, p = 0.045) were associated with stroke recurrence or all-cause death after CS. On the log-rank test (using the discriminatory cut-off value of LASr <23%), LASr (p = 0.009) was associated with higher risk of the primary outcome. In conclusion, lower values of the LAS reservoir were associated with a higher risk of stroke recurrence or death after CS. LAS may identify patients at higher risk of thromboembolism and stress conditions.

Atrial Cardiopathy: Redefining Stroke Risk Beyond Atrial Fibrillation

Atrial fibrillation (AF) and ischemic stroke are dual epidemics in society, both associated with poor clinical outcomes, patient disability, and significant healthcare expenditure. The conditions are interrelated and share complex causal pathways. Risk stratification algorithms such as the CHADS₂ and CHA₂DS₂-VASc score offer predictive value in stroke and systemic embolism risk in the AF population, however, have limitations. Recent evidence suggests that an intrinsically prothrombotic atrial substrate may precede and promote AF and lead to thromboembolic events independent of the arrhythmia, allowing for a window of intervention before arrhythmia detection and development of ischemic stroke. Initial work has found incremental value in addition of parameters of atrial cardiopathy to traditional stroke risk stratification algorithms, however, requires evaluation with dedicated prospective randomized studies before use in real-world clinical practice. In this narrative review, we explore current evidence and literature on the use of measures of atrial cardiopathy in stroke risk stratification and management.

Reduced Left Atrial Appendage Flow Is Associated With Future Atrial Fibrillation After Cryptogenic Stroke

BACKGROUND

Hemostasis within the left atrial appendage (LAA) is a common cause of stroke, especially in patients with atrial fibrillation (AF). Although LAA flow provides insights into LAA function, its potential for predicting AF has yet to be established. The aim of this study was to explore whether LAA peak flow velocities early after cryptogenic stroke are associated with future AF on prolonged rhythm monitoring.

METHODS

A total of 110 patients with cryptogenic stroke were consecutively enrolled and underwent LAA pulsed-wave Doppler flow assessment using transesophageal echocardiography within the early poststroke period. Velocity measurements were analyzed offline by an investigator blinded to the results. Prolonged rhythm monitoring was conducted on all participants via 7-day Holter and implantable cardiac monitoring devices, with follow-up conducted over a period of 1.5 years to determine the incidence of AF. The end point of AF was defined as irregular supraventricular rhythm with variable RR interval and no detectable P waves lasting ≥30 sec during rhythm monitoring.

RESULTS

During a median follow-up period of 539 days (interquartile range, 169-857 days), 42 patients (38%) developed AF, with a median time to AF diagnosis of 94 days (interquartile range, 51-487 days). Both LAA filling velocity and LAA emptying velocity (LAAev) were lower in patients with AF (44.3 ± 14.2 and 50.7 ± 13.3 cm/s, respectively) compared with patients without AF (59.8 ± 14.0 and 76.8 ± 17.3 cm/sec, respectively; P < .001 for both). LAAev was most strongly associated with future AF, with an area under the receiver operating characteristic curve of 0.88 and an optimal cutoff value of 55 cm/sec. Age and mitral regurgitation were independent determinants of reduced LAAev.

CONCLUSIONS

Impaired LAA peak flow velocities (LAAev < 55 cm/sec) in patients with cryptogenic stroke are associated with future AF. This may facilitate the selection of appropriate candidates for prolonged rhythm monitoring to improve its diagnostic accuracy and implementation.

A Bibliometric Analysis of Cardioembolic Stroke From 2012 to 2022

Cardioembolic stroke, a subtype of ischemic stroke with the worst prognosis, is quietly threatening public health. We aimed to visualize the development trend and hotspots of research on cardioembolic stroke. A total of 2886 papers about cardioembolic stroke published from 2012 to 2022 were retrieved in the Web of Science Core Collection (WoSCC) database. Further, we performed a bibliometric analysis of these publications, such as generating cooperation maps, co-citation analysis of journals and references, and cluster analysis of keywords. According to the results, cardioembolic stroke research faces many clinical challenges. We obtained the knowledge maps of countries/institutions, authors, journals with high publications and citations, and representative references in this field. Studies about optimal prevention strategies for cardioembolic stroke, identification of cardioembolism in cryptogenic stroke, and prophylactic anticoagulation for patients with embolic stroke of undetermined source (ESUS) or at high risk of left ventricle (LV) thrombus are in the spotlight.