Left atrial cross-sectional area is a novel measure of atrial shape associated with cardioembolic strokes

History of stroke as a predictor of high left atrial fibrosis in patients with persistent atrial fibrillation-insight from the DECAAF II randomized trial

BACKGROUND

There is a strong relationship between left atrial (LA) remodeling and ischemic stroke (IS) risk in atrial fibrillation (AF) patients. The Efficacy of Delayed Enhancement MRI-Guided Ablation vs. Conventional Catheter Ablation of Atrial Fibrillation (DECAAF-II) is the biggest MRI-based, randomized, multicenter clinical trial performed on persistent AF patients. The aim of this study is to evaluate the relationship between history of stroke and atrial fibrosis in the DECAAF II population.

METHODS

Persistent AF patients who underwent Late Gadolinium Enhancement Magnetic Resonance Imaging (LGE-MRI) were included in the study and divided into two different groups: those with a history of stroke and those without. Propensity score matching was performed to adjust for covariates. Atrial fibrosis was compared in both groups. Then, patients were divided into different fibrosis groups, using three different cut-offs of baseline atrial fibrosis: ≥ 15%, ≥ 20%, and ≥ 25%. Univariate logistic regression and adjusted multivariate analysis were performed to assess the effect of clinical characteristics and risk factors on baseline fibrosis.

RESULTS

Eight-hundred forty-three patients were recruited in DECAAF II, of whom 70 (8.3%) had a history of stroke. Patients with history of stroke had a higher prevalence of hypertension (p = 0.043), diabetes (p = 0.014), and hyperlipidemia (p = 0.001). Seventy patients with no history of strokes were matched with patients with history of stroke to adjust for covariates using propensity score analysis. Patients in the stroke group had a significantly higher level of fibrosis than those without (20.2% vs. 8.1%, p = 0.017). Increased age was a significant predictor of all three baseline fibrosis classes (≥ 15%, ≥ 20%, and ≥ 25%). Additionally, history of stroke was found to be a predictor of baseline fibrosis ≥ 25% even after adjusting for other clinical characteristics and risk factors (OR = 1.98 [1.14-3.43], p = 0.01).

CONCLUSIONS

Left atrial fibrosis level greater than 25% correlates with the history of previous stroke episodes in patients with persistent atrial fibrillation.

Embolic Stroke of Undetermined Source: Approaches in Risk Stratification for Cardioembolism

Ischemic stroke is a leading cause of morbidity and mortality worldwide. Embolic stroke of undetermined source has been recently proposed to categorize nonlacunar ischemic strokes without confirmed etiology after adequate investigation with a likely embolic stroke mechanism. A strategy of empirical anticoagulation for embolic stroke of undetermined source patients is attractive but may only be beneficial in a select subset of patients. Strategies which would help identify the subset of embolic stroke of undetermined source patients most likely to have cardioembolic origin of stroke, and hence benefit from anticoagulation, are needed. This article will review current evidence which may be useful in the development of a risk stratification approach based on arrhythmia monitoring, cardiac imaging, and clinical risk stratification. This approach may be beneficial in clinical practice in improving patient outcomes and reducing stroke recurrence in this population; however, further work is required with active trials underway.

Statistical shape analysis of the left atrial appendage predicts stroke in atrial fibrillation

The shape of the left atrium (LA) and left atrial appendage (LAA) have been shown to predict stroke in patients with atrial fibrillation (AF). Prior studies rely on qualitative assessment of shape, which limits reproducibility and clinical utility. Statistical shape analysis (SSA) allows for quantitative assessment of shape. We use this method to assess the shape of the LA and LAA and predict stroke in patients with AF. From a database of AF patients who had previously undergone MRI of the LA, we identified 43 patients with AF who subsequently had an ischemic stroke. We also identified a cohort of 201 controls with AF who did not have a stroke after the MRI. We performed SSA of the LA and LAA shape to quantify the shape of these structures. We found three of the candidate LAA shape parameters to be predictive of stroke, while none of the LA shape parameters predicted stroke. When the three predictive LAA shape parameters were added to a logistic regression model that included the CHA₂DS₂-VASc score, the area under the ROC curve increased from 0.640 to 0.778 (p = .003). The shape of the LA and LAA can be assessed quantitatively using SSA. LAA shape predicts stroke in AF patients, while LA shape does not. Additionally, LAA shape predicts stroke independent of CHA₂DS₂-VASc score. SSA for assessment of LAA shape may improve stroke risk stratification and clinical decision making for AF patients.