Left Atrial Appendage Closure for Stroke Prevention in Atrial Fibrillation

The cessation of oral anticoagulation following left atrial appendage surgery

Atrial fibrillation is associated with a significantly increased risk of stroke, and oral anticoagulation is the mainstay of preventative treatment. Scenarios arise where the risks of treatment with oral anticoagulation may outweigh the benefits, most commonly when there is an elevated risk of bleeding. Studies of percutaneous closure of the left atrial appendage have strongly implicated this structure in the etiology of stroke in atrial fibrillation, and provide some rationale for the discontinuation of oral anticoagulation following percutaneous closure device implantation. A common clinical concern is the safety of cessation of oral anticoagulation after surgical closure of the left atrial appendage in patients with a history of atrial fibrillation. Here, we review the evidence guiding this management decision and draw comparison with data on percutaneous closure.

The impact of the latest echocardiographic chamber quantification recommendations on the prediction of left atrial appendage thrombus presence by transthoracic echocardiography

INTRODUCTION

The latest recommendations for echocardiographic chamber quantification have implemented updated normal values for all cardiac chambers.

PURPOSE

To evaluate the incidence of normal and abnormal values of routine echocardiographic parameters such as left ventricular ejection fraction (LVEF) and left atrial volume indexed to body surface area (LAVi) in patients with non-valvular atrial fibrillation (AF) and to determine the influence of LVEF and LAVi reclassification on the prediction of LAAT by transthoracic echocardiography.

METHODS

We retrospectively analysed the database of 1674 transesophageal echocardiograms performed between 2012 and 2015 in our echo lab. The study involved patients (mean age 70 ± 7 years, 80% men) with paroxysmal or persistent AF (35 patients with left atrial appendage thrombus [LAAT] and 35 sex- and age-matched controls without LAAT). LVEF and LAVi were categorised in two ways: semi-quantitative using four-degree scale (normal or abnormal graded from mild and moderate to severe) and qualitative (normal vs. abnormal).

RESULTS

We reclassified 6 (9%) and 4 (6%) patients with regard to LVEF as well as 38 (54%) and 16 (23%) with regard to LAVi on semi-quantitative and qualitative scale, respectively. After adjustment for effective anticoagulation and approved risk factors in the multivariate models, we identified LVEF categorised in semi-quantitative manner according to both documents, LAVi categorised in a binary manner by new guidelines and semi-quantitative scale by both recommendations as independently associated with LAAT.

CONCLUSIONS

Differentiation between normal and abnormal value enhanced the diagnostic meaning of LAVi in the aspect of higher LAAT risk. LVEF reclassification had no significant influence.

Changes in Coagulation and Platelet Activation Markers Following Transcatheter Left Atrial Appendage Closure

The recommendations for antithrombotic treatment after left atrial appendage closure (LAAC) remain empirical, and no data exist on the changes in hemostatic markers associated with LACC. The objective of the present study is to determine the presence, degree, and timing of changes in the markers of platelet and coagulation activation after LAAC. Forty-three patients (mean age 76 ± 9 years, 23 men) with atrial fibrillation who underwent successful LACC with the Watchman (n = 27) or Amplatzer Cardiac Plug (n = 16) devices were included in the study. Patients received antiplatelet therapy after LAAC (aspirin + clopidogrel: 27 patients; single antiplatelet therapy with aspirin or clopidogrel: 16 patients). Prothrombin fragment 1+2 and thrombin-antithrombin III were used as markers of coagulation activation, and soluble P-selectin and soluble CD40 ligand were used as markers of platelet activation. Measurements of all hemostatic markers were performed at baseline just before the procedure, followed by days 7, 30, and 180 after LAAC. Prothrombin fragment 1+2 and thrombin-antithrombin levels increased from 0.27 nmol/L and 4.68 ng/ml, respectively, at baseline to peak values of 0.43 nmol/L and 9.76 ng/ml, respectively, at 7 days, partially returning to baseline levels at days 30 and 180 after LAAC (p <0.001 for both markers). No clinical or procedural factors were associated with a greater increase in the markers of coagulation activation after LAAC. Levels of soluble P-selectin and soluble CD40 ligand did not change at any time after LAAC. In conclusion, transcatheter LAAC is associated with significant activation of the coagulation system, yet without evidence of significant platelet activation.