Complex Left Atrial Appendage Morphology Is an Independent Risk Factor for Cryptogenic Ischemic Stroke

Abstract

Importance: Ischemic strokes pose a significant health burden. However, the etiology of between 20 and 40% of these events remains unknown. Left atrial appendage morphology may influence the occurrence of thromboembolic events.Design: A retrospective cross-sectional study was conducted to investigate the role of LAA morphology in patients with atrial fibrillation (AF) and cardioembolic-associated stroke and patients with cryptogenic stroke without atrial fibrillation. LAA morphology is classified into two groups: (1) simple (chicken-wing) vs. (2) complex (non-chicken wing) based on transesophageal echocardiography (TEE) findings. In addition to the LAA morphology, left atrial parameters, including orifice diameter, depth, emptying velocity, and filling velocity, were collected for both groups. Mathematical, computational models were constructed to investigate flow velocities in chicken-wing and non-chicken wing morphological patterns to assess LAA function further.Findings: TEE values for volume, size, emptying, and filling velocities were similar between simple and complex LAA morphology groups. Patients with cryptogenic stroke without coexisting AF were noted to have significantly higher rates of complex LAA morphology. Chicken-wing LAA morphology was associated with four-fold higher flow rate (kg/s) in computational simulations.Conclusions: Complex LAA morphology may be an independent contributing factor for cryptogenic strokes. Further studies are warranted to investigate the mechanism involved in LAA morphology and thromboembolic events.

Linking statistical shape models and simulated function in the healthy adult human heart

“…Secondly, we did not include the LA appendage for consistency, it was out of the CT image field of view in some of the cases. The anatomy of the LA appendage has been shown to be a key factor for instance in ischaemic stroke [ 88 ] or in the design of occluders to avoid thrombus [ 89 ]. To include this in the atlas, a larger cohort with multiple occurrences of variants of left atrial anatomies would be required.…”

Giant left atrial appendage aneurysm and atrial fibrillation: chicken or the egg?

“…In recent time, understanding of LAA morphology has become important as studies have demonstrated that complex LAA morphology is an independent predictor of AF and stroke 9 10. In our case, the patient had no risk factors for AF and giant LAAA may be contributing to her AF, as patients with congenital LAAA usually present at an earlier age 4.…”

Stroke risk evaluation for patients with atrial fibrillation: Insights from left atrial appendage

“…As the first study to focus on the association between stroke risk and LAA shape, Di Biase's research obtained considerable attention. Subsequent independent investigations conclusively established chicken wing as the “safe” LAA type ( 32 , 33 ), and from that point to present, the consensus that chicken wing type LAA is least likely to result in stroke (i.e., is the “safe” LAA type) is widely accepted in clinical practice ( 34 ).…”

“…Given the results of these studies, researchers subsequently combined the three “non-chicken wing” shapes into a single category and conducted studies to confirm an “unsafe” designation for risk of stroke on the “non-chicken wing” type ( 41 – 43 ). The simplification and efficiency of this two-type classification scheme is widely recognized in clinic ( 33 , 34 ).…”