Predictors of Device-Related Thrombus After Left Atrial Appendage Occlusion: TED-F₂ Score

Left atrial appendage (LAA) occlusion (LAAO) is performed to prevent LAA thrombus in patients with atrial fibrillation (AF). The risk of device-related thrombus (DRT) on the atrial side of the LAAO device is approximately 4%. Identifying patients at high risk of DRT would enable closer surveillance and more-aggressive anticoagulation to prevent post-LAAO DRT-related stroke.

From the LAAO registry at The University of Kansas Medical Center, we identified patients who developed DRT. We chose 3 unmatched controls per DRT case from LAAO recipients without DRT. Predictor variables were obtained from transesophageal echocardiogram reports and/or images, transthoracic echocardiogram reports, and chart review. Implant depth was measured from the limbus of the left atrial ridge to the centre of the atrial aspect of the LAAO device, on a 45° transesophageal echocardiogram view.

We identified 26 patients with DRT (aged 77.7 ± 9.7 years; 34.6% female) and selected 78 unmatched controls without DRT. Univariate predictors of DRT, comprising a novel TED-F₂ score, included history of venous Thromboembolism (23.1% vs 5.1%, P = 0.01), an LAA Emptying velocity ≤ 20 cm/s (45.8% vs 18.9%, P = 0.01), an implant Depth > 2 cm (34.6% vs 12.8%, P = 0.02), and presence of AF rhythm at time of device implantation (50.0 % vs 11.5%, P = 0.0001). A TED-F₂ score of ≥ 3 was very strongly associated with DRT-odds ratio 12.5 (95% confidence interval, 3.8-41.1, P < 0.0001).

We propose a novel risk score to predict development of DRT after LAAO, comprising history of venous Thromboembolism, LAA Emptying velocity ≤ 20 cm/s, implant Depth > 2 cm (1 point each), and an AF rhythm at implantation (2 points). A TED-F₂ risk score of ≥ 3 identified patients who are at greatly elevated risk of developing DRT.