Derivation and validation of E/e′ ratio as a parameter in the evaluation of left atrial appendage thrombus formation in patients with nonvalvular atrial fibrillation
We sought to determine and prospectively validate, with concomitantly performed transthoracic (TTE) and transesophageal echocardiograms (TEE), a TTE-assessed E/e′ threshold that can be useful in predicting left atrial appendage (LAA) thrombus in patients with nonvalvular atrial fibrillation (NVAF). The retrospective derivation cohort was comprised of 297 patients with NVAF with TTE performed within 1 year of TEE. The validation cohort was comprised of 266 prospectively enrolled patients with TTE performed immediately prior to TEE. LAA thrombus was detected by TEE in 6.4 % of patients in both cohorts. Receiver operating characteristic (ROC) analyses demonstrated a good discriminatory capacity of lateral E/e′ in predicting LAA thrombus in the derivation cohort (AUC 0.72; CI 0.63–0.82; P = 0.001) which was confirmed in the validation cohort (AUC 0.83; CI 0.75–0.91; P < 0.001). In the derivation cohort, ROC curve point-coordinates identified E/e′ thresholds of both 9.0 and 8.0 to be associated with 100 % sensitivity, with specificities of 36 and 30 %, respectively. An E/e′ threshold of ≥8 was selected a priori for prospective validation, and was associated with 100 % sensitivity and 41 % specificity for LAA thrombus, with positive and negative predictive values of 10 and 100 %, respectively, and positive and negative likelihood ratios of 1.69 and 0, respectively. We determined and validated an E/e′ threshold of 8 as a highly sensitive and useful parameter that can aid in identifying patients at very low risk for LAA thrombus and potentially obviate the need for a TEE prior to electrophysiology procedures and restoration of sinus rhythm.
KeywordsAtrial fibrillation Left atrial appendage thrombus Transesophageal echocardiogram (TEE) Transthoracic echocardiogram (TTE) E/e′ ratio
Area under the curve
95 % confidence intervals
Left atrial appendage
Nonvalvular atrial fibrillation
Receiver operating characteristic
Spontaneous echo contrast
The study was funded by a Rush-County collaborative research grant. The grant fiduciary was Rush University Medical Center; the principal investigator was Dr. Doukky. The funding source had no input into the study design, execution, data analysis and interpretation, or manuscript preparation and approval.
Dr. Doukky receives research funding from Astellas Pharma US and serves on the Advisory Board of Astellas Pharma US; none of these conflicts are relevant to the present work. Other authors report no conflicts.
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