The early experience in Europe with the next-generation Amplatzer Amulet has shown signs of device thrombosis in 16.7% of cases after implantation for left atrial appendage (LAA) closure.
That proportion of atrial fibrillation (Afib) patients exhibited signs of device thrombosis on transesophageal echocardiography after 11 weeks on average — despite continued dual antiplatelet therapy in 95.6% of cases, according to results published online in JACC: Clinical Electrophysiology by Cristoph Hammerstingl, MD, PhD, of University of Bonn in Germany, and colleagues.
“All thrombi were observed within the untrabeculated region of the LAA ostium between the left upper pulmonary vein ridge and the occluder-disc, indicating suboptimal LAA occlusion,” the investigators suggested, emphasizing “the need for an optimized post-LAA occlusion anticoagulation regimen, a revised implantation strategy and possibly modified patient selection criteria.”
Hammerstingl’s team studied the outcomes of 24 Afib patients who were treated with the Amplatzer Amulet system for stroke prevention, which was cleared for use in Europe in 2013 but is not on the U.S. market.
Clots on the Amplatzer Amulet were more likely for those with numerically higher degrees of spontaneous echo contrast grades within the LAA (3.0 versus 1.3), lower LAA peak emptying velocities (17.5 cm/s versus 48.3 cm/s), decreased left ventricular function (39% versus 50%), and a history of LAA thrombi (75.0% versus 19.2%).
Direct-acting oral anticoagulants resolved device thrombi; no strokes or bleeding events were observed at 6 weeks.
Even so, “given the limited patient number included in this analysis, large scale randomized studies are needed to further address this topic and general recommendations cannot be given at this point,” commented Hammerstingl and colleagues.
Hammerstingl reported no relevant conflicts of interest.
JACC: Clinical Electrophysiology
Sedaghat A, et al “Thrombus formation after left atrial appendage occlusion with the Amplatzer Amulet device” JACC Clin Electrophysiol 2016; DOI: 10.1016/j.jacep.2016.05.006.