Correlation between quantitative left atrial spontaneous echocardiographic contrast and intact fibrinogen levels in mitral stenosis

Severe Left Atrial Spontaneous Echo Contrast in Nonvalvular Atrial Fibrillation: Clinical Characteristics and Impact on Ischemic Risk Postablation

BACKGROUND

 Spontaneous echo contrast (SEC) is an important precursor for intracardiac thrombus and stroke. There are very limited data on characteristics of severe SEC and its impact on ischemic risk of nonvalvular atrial fibrillation (NVAF) patients after radiofrequency catheter ablation.

METHODS

 Transesophageal echocardiography files were reviewed between March 2009 and March 2021 in this monocentric retrospective study. SEC was classified into four levels. The primary endpoint was thromboembolic event (stroke, myocardial infarction, systemic embolism, and ensuing death), and the secondary endpoint included nonischemic mortality and recurrent atrial arrhythmia.

RESULTS

 Six hundred SEC cases were enrolled and classified into mild SEC group (Grade 1-2, n = 515) and severe SEC group (Grade 3-4, n = 85). Independent risk factors for severe SEC included higher brain natriuretic peptide (BNP), erythrocyte sedimentation rate (ESR), and LAd/∆LVED (LAd = left atrial diameter; ∆LVED = left ventricular end-diastolic diameter - left ventricular end-systolic diameter). The severe SEC group had a higher peri-procedural ischemic event occurrence (7.1 vs. 1.9%, p = 0.007). At a median follow-up of 55 months, the severe SEC group had a lower freedom rate from ischemic events (90.1 vs. 75.3%, p < 0.001); older age and severe SEC were independent risk factors for ischemic events. In patients undergoing redo-procedure (n = 100), a remarkably reduced ESR (17.8 ± 12.0 vs. 28.2 ± 19.0 mm/h, p < 0.001) was observed in patients whose SEC disappeared.

CONCLUSIONS

 Higher BNP, ESR, and LAd/∆LVED were the independent predictors for severe SEC. Severe SEC was associated with higher peri-procedural and long-term ischemic risks. ESR and LAd/∆LVED, as indicators of hematological and hemodynamic change, seemed helpful in identifying NVAF patients prone to developing severe SEC.

The Comparison of the Diagnostic Value of Left Atrial Pulmonary Vein Single-Phase and Dual-Phase Enhanced CT Scanning for Left Atrial Appendage Thrombosis and SEC in Patients with Atrial Fibrillation

Objective

The accuracy of left atrial pulmonary vein CT enhanced single-phase and dual-phase scanning in the detection of left atrial appendage (LAA) thrombosis and spontaneous echo contrast (SEC) before radio frequency ablation was compared in atrial fibrillation patients, so as to optimize the scanning scheme.

Methods

78 patients with atrial fibrillation who were admitted to Cangzhou Central Hospital from October 2020 to September 2021 and underwent bilateral enhanced CT scan of left atrial pulmonary vein and transesophageal echocardiography (TEE) examination for planned frequency ablation were selected. TEE results were used as the "gold standard" to compare the diagnostic efficacy of the first phase, second phase, and double-phase comprehensive mode of enhanced left atrial pulmonary vein CT in detecting left atrial thrombosis and SEC.

Results

The sensitivity, specificity, positive predictive value, and negative predictive value were 88.9%, 84.1%, 42.1%, and 98.3%, respectively, in the detection of left atrial thrombosis and SEC by the first phase of CT enhanced scan. The sensitivity, specificity, positive predictive value, and negative predictive value were 22.2%, 98.6%, 66.6%, and 90.7%, respectively, in the detection of left atrial thrombosis and SEC by the second phase of CT enhanced scan. The sensitivity, specificity, positive predictive value, and negative predictive value were 88.9%, 84.1%, 42.1%, and 98.3%, respectively, in the detection of left atrial thrombosis and SEC by the double-phase comprehensive mode of CT enhanced scan. There was no statistically significant difference in the accuracy of CT diagnosis of left atrial appendage thrombosis and SEC between the three modes of the first phase, the second phase, and the double-phase comprehensive CT (P > 0.05). The mean effective radiation dose of double-phase enhanced scan was 7.49 ± 1.02 mSv.

Conclusion

Single-phase enhanced CT scan of left atrial pulmonary vein can meet clinical requirements and significantly reduce the radiation dose compared with double-phase enhanced CT scan. Therefore, it is recommended as an initial screening examination for patients with atrial fibrillation before radiofrequency ablation.