Poor Distal Left Atrial Appendage Opacification on Early-Phase Cardiac CTA and Association With Arterial Thromboembolism

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Non-valvular atrial fibrillation (n=389). Intervention: Poor distal left atrial appendage opacification (LAA-PCO) on early-phase cardiac CTA vs. Normal LAA opacification. Primary outcome: Arterial thromboembolism (ischemic stroke and other systemic arterial embolism) (OR 2.120, 95% CI 1.163-3.865, p=0.014).

Tao He; Cong Lu; Tiantian Luo Luo; Jie Zeng

doi:10.31083/rcm47945

June 25, 2026Reviews in Cardiovascular MedicineOpen Access

Poor Distal Left Atrial Appendage Opacification on Early-Phase Cardiac CTA and Association With Arterial Thromboembolism

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Key result

Poor LAA opacification on early-phase CTA is linked to ~112% higher arterial thromboembolism risk in NVAF.

OR 2.120
95% CI 1.163-3.865
P=0.014
n=389

Figures

Why the study?

Poor contrast opacification of the distal LAA on early-phase cardiac CTA may reflect blood stasis predisposing to thrombus, but its association with arterial thromboembolism in non-valvular AF required evaluation.

Is poor distal LAA opacification on early-phase CTA associated with arterial thromboembolism in patients with non-valvular AF?

Key Points

To evaluate the association between early-phase left atrial appendage poor contrast opacification (LAA-PCO) on cardiac CTA and arterial thromboembolic events in patients with non-valvular atrial fibrillation.
Analyzed 389 consecutive adult patients with non-valvular atrial fibrillation undergoing early-phase cardiac CTA between January 2020 and December 2023 in a single-center retrospective cohort study.
Assessed qualitative distal LAA-PCO and quantified Hounsfield unit (HU) densities to derive ostium-to-distal (O/D) and left atrium/descending aorta-normalized corrected O/D ratios.
Identified risk factors for ischemic stroke and systemic arterial embolism using multivariate logistic regression and evaluated discrimination using receiver operating characteristic analysis and the C-index.
Distal LAA-PCO was observed in 17.48% of patients overall and occurred at a significantly higher rate in the embolic group than in the non-embolic group (27.88% vs. 13.68%, p = 0.001).
Multivariate regression demonstrated independent associations with arterial embolism for CHA2DS2-VASc score (OR = 2.442; 95% CI = 2.0–2.982; p = 0.001), LAA-PCO (OR = 2.120; 95% CI = 1.163–3.865; p = 0.014), O/D ratio (OR = 1.250; 95% CI = 1.074–1.454; p = 0.004), and corrected O/D ratio (OR = 1.325; 95% CI = 1.107–1.586; p = 0.002).
Adding the corrected O/D ratio to the CHA2DS2-VASc score improved discrimination for arterial embolism from a C-index of 0.85 to 0.87.

Study Design

Type

Cohort (n=389)

Multicenter

No

Structured PICO

Is poor distal LAA opacification on early-phase CTA associated with arterial thromboembolism in patients with non-valvular AF?

P

Population

389 adult patients with non-valvular atrial fibrillation scheduled for LAA occlusion or radiofrequency ablation, evaluated retrospectively for the association between early-phase LAA opacification and arterial embolic events.

E

Exposure

Poor contrast opacification (PCO) of the distal left atrial appendage (LAA) on early-phase cardiac CTA, including quantitative O/D ratio and corrected O/D ratio

C

Comparator

Normal LAA opacification / lower O/D ratios

O

Outcome

Arterial thromboembolic events (including ischemic stroke)hard clinical

Main Result

Odds Ratio: 2.12 (95% CI 1.163–3.865)

p-value: p=0.014

Limitations

Retrospective cross-sectional design precludes demonstration of a prospective causal relationship
CTA attenuation values are influenced by multiple technical and physiologic factors which can introduce measurement variability
Lack of a standardized, universally accepted threshold for defining clinically significant O/D ratio
Analyses involving LAA emptying velocity were based on a small subgroup with limited statistical power
Single-center study design may limit generalizability to broader AF populations
Imputation of missing data using mean or median values may introduce additional bias
Composite endpoint combining ischemic stroke and systemic embolism may introduce some heterogeneity
Requires prospective validation
Requires standardization of CT protocols

Implication

May stratify thromboembolism risk via CTA in non-valvular AF; hypothesis-generating and should not yet alter practice.

Abstract

Background:Poor contrast opacification (PCO) of the distal left atrial appendage (LAA) on early-phase cardiac computed tomography angiography (CTA) may reflect impaired LAA hemodynamics and blood stasis, potentially predisposing to thrombus formation and embolic events. Thus, this study aimed to evaluate the association between early-phase LAA-PCO and arterial thromboembolic events in patients with non-valvular atrial fibrillation (AF).Methods:In this single-center retrospective cohort study, 389 consecutive adult patients with non-valvular AF who underwent cardiac CTA were analyzed between January 2020 and December 2023. Qualitative LAA-PCO on early-phase CTA and quantitative Hounsfield unit (HU) measurements at the LAA ostium, mid-body and distal LAA, left atrium (LA), and descending aorta (DA) were recorded. The O/D ratio (LAA-ostium HU/distal LAA HU) and a corrected O/D ratio normalized by LA/DA attenuation were calculated. Associations with ischemic stroke and other arterial embolic events were assessed using multivariate logistic regression, and model discrimination was assessed using the C-index.Results:Of the 389 patients, 104 experienced arterial embolic events, including 102 ischemic strokes. LAA-PCO was present in 68 patients (17.48%) and was more common in the embolic group (27.88% vs. 13.68%, p = 0.001). The embolic group had significantly lower distal LAA HU and higher O/D and corrected O/D ratios. In the multivariate analysis, the CHA2DS2-VASc score (odds ratio (OR) = 2.442; p = 0.001), LAA-PCO (OR = 2.120; p = 0.014), O/D ratio (OR = 1.250; p = 0.004) and corrected O/D ratio (OR = 1.325; p = 0.002) were independently associated with arterial embolism. A model combining the CHA2DS2-VASc score and the corrected O/D ratio showed a relatively high C-index of 0.87.Conclusions:Poor distal LAA opacification on early-phase CTA is associated with arterial thromboembolism in patients with non-valvular AF and may provide complementary information to the CHA2DS2-VASc score for thromboembolic risk assessment. Prospective validation and standardization of computed tomography (CT) protocols are needed before clinical implementation.

Discussion

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Cite This Study

He et al. (2026) conducted a cohort in Non-valvular atrial fibrillation (n=389). Poor distal left atrial appendage opacification (LAA-PCO) on early-phase cardiac CTA vs. Normal LAA opacification was evaluated on Arterial thromboembolism (ischemic stroke and other systemic arterial embolism) (OR 2.120, 95% CI 1.163-3.865, p=0.014). Poor distal left atrial appendage opacification on early-phase cardiac CTA was independently associated with an increased risk of arterial thromboembolism (OR 2.120) in patients with non-valvular atrial fibrillation.

synapsesocial.com/papers/6a5bb213179330b960981791 https://doi.org/10.31083/rcm47945

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Poor Distal Left Atrial Appendage Opacification on Early-Phase Cardiac CTA and Association With Arterial Thromboembolism

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Poor Distal Left Atrial Appendage Opacification on Early-Phase Cardiac CTA and Association With Arterial Thromboembolism

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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