the main - stay therapy for this condition is chronic oral anticoagulation , however , in patients with a high bleeding risk profile or prior life - threatening bleed , conventional therapy may not be ideal . new advanced technologies such as transcatheter closure of the left atrial ( la ) appendage ( laa ) provides clinicians an alternative therapy to reduce the stroke risk in patients with contraindications to chronic oral anticoagulation . in this case , we present a 66-year - old male with chronic af who underwent laa closure and was found to have a large thrombus attached to the device a year later . this case is valuable for dealing with thrombus formation even after one year device closure . several studies of the percutaneous transcatheter delivery of dedicated laa occlusion devices have shown promising results that offer an alternative to warfarin therapy for selected patients . despite the encouraging results of several studies about the procedure , additional studies are needed to verify the safety and effectiveness of the devices . as in the present case , thrombosis might be a possible late complication and information to guide imaging monitoring and treatment is lacking . a 66-year - old male with an extensive past medical history including hypertension , hyperlipidemia , diabetes , metastatic prostate cancer treated with prostatectomy along with radiation and chemotherapy , previous ischemic stroke , known severe 3-vessel coronary artery disease with coronary bypass grafting surgery after myocardial infarction , preserved ejection fraction of 50% , and chronic af on anti - coagulation with warfarin . the patient suffered a fall resulting in left cerebellar hemorrhage , left temporal lobe subarachnoid hemorrhage as well as encephalomalacia of posterior right frontal lobe due to intraparenchymal hemorrhage . due to his inability to tolerate long - term anticoagulation and high chads2 score of 5 , he underwent percutaneous laa closure using a 16 mm amplatzer muscular ventricular septal defect closure device ( aga medical corp . , plymouth , mn , usa ) . he was not a candidate for lariat device ( sentreheart , redwood city , ca , usa ) due to prior cardiac surgery . the device was deployed with no complications and no residual flow . the patient was placed on life - long daily aspirin 81 mg and a three - month course of clopidogrel 75 mg . transthoracic 2d - echocardiogram performed post - procedure , 45 days , and at 6 month follow - up was unremarkable for device complications . however , the 1 year follow - up transthoracic 2d - echocardiogram revealed a spherical echo dense structure measuring 2.38  1.42 cm suggestive of clot in the left atrium ( fig . 1 , 2 , and 3 , supplementary movie 1 and 2 ) . transesophageal echocardiogram demonstrated a bilobed echo dense mass in the la , the smaller being 1.53  1.87 cm and the larger mass being 2.45  2.33 cm ( fig . 4 and 5 , supplementary movie 3 ) . repeat transthoracic echocardiogram six months later did not reveal any evidence of residual thrombus on contrast imaging . his warfarin was subsequently discontinued and he has been maintained on daily 81 mg aspirin . he has remained asymptomatic from a cardiac and neurological standpoint and is regularly followed by cardiology . af is the most common sustained cardiac arrhythmia and increases the risk for stroke.1 ) laa is the site of around 7590% of thrombus formation in non - valvular af , and thus obliteration or exclusion of this structure , at least in theory , should lead to stroke risk reduction.2 ) three devices have been specifically designed for laa occlusion : the percutaneous left atrial appendage transcatheter occlusion ( plaato ) , the watchman ( atritech , boston scientific , natick , ma , usa ) laa system , and the amplatzer cardiac plug ( acp ) ( aga , st . jude medical , minneapolis , mn , usa).3 ) the plaato device has been discontinued for commercial reasons . the embolic protection in patients with atrial fibrillation trial compared closure of the laa with the watchman device with long - term warfarin therapy and found it was non - inferior to standard anticoagulant therapy for stroke prophylaxis in high - risk af patients.4 ) recently , the asa plavix feasibility study with watchman left atrial appendage closure technology study found that laa closure with the watchman device can be safely performed without a warfarin transition , and is a reasonable alternative to consider for patients at high risk for stroke but with contraindications to systemic oral anticoagulation.5 ) a variety of amplatzer septal occluder devices ( aga , st . paul , mn , usa ) have been available for many years and used extensively for closure of atrial and ventricular septal defects and other cardiac shunts . eventually , a novel device , the acp , was developed for the purpose of closing the laa . similar to prior trans - catheter laa closure devices , the acp system is delivered into the left atrium via a trans - septal approach . the relatively short length of the acp device allows for implantation into shallow laa variants , which gives it an advantage over the plaato and watchman devices that require a deeper laa anatomy because of their longer profiles.3 ) the incidence of thrombus formation on devices is relatively uncommon with prior studies showing an incidence for the watchman device thrombus formation between 24%.5)6)7 ) in a study by urena et al.,8 ) none of the 52 patients developed a device thrombus on the amplatzer device ; however , there have been two case reports from europe.9)10 ) prior studies demonstrate high stroke risk score , high pre - procedural platelet count , and low left ventricular ejection fraction as independent risk factors for the formation of thrombus on the acp device.7 ) transthoracic echocardiogram has a lower sensitivity to identify la thrombus . use of contrast - enhanced echocardiography significantly improves the sensitivity for identifying intra - cardiac masses when standard imaging does not reveal diagnostic information.11 ) individuals who will benefit from laa closure are probably those who are at the highest risk for both stroke and hemorrhagic complications ; therefore , patient selection is of paramount importance in order to realize the optimal device and antithrombotic strategy . as in the present case , thrombosis might be a rare , but possible complication of device - based antithrombotic therapy , and additional studies are needed to know if the current practice of treating patients only with double - antiplatelet therapy before endothelization of the device is sufficient , or if one should use oral anticoagulation in the first 3 months as is advised in biological prostheses . in addition , periodic surveillance by echocardiography with contrast should be recommended to monitor the formation of thrombus in all types of devices . the frequency , duration , and type of echocardiogram ( transthoracic or transesophageal ) for thrombus formation monitoring still needs further research . three chamber view movie clip showing a stalk with pedunculated thrombus contrast - enhanced echocardiogram movie clip showing enhanced view of thrombus transesophageal echocardiogram movie clip confirms a large bi - lobed thrombus
device based closure of the left atrial appendage ( laa ) has emerged as a viable approach for stroke prevention in atrial fibrillation ( af ) patients with contraindications to chronic oral anticoagulation . 
 one of the most feared complications is device related thrombus formation . 
 we present a 66-year - old male with chronic af who developed a life - threatening intracranial bleed on oral anti - coagulation . 
 he subsequently underwent laa closure using an amplatzer muscular ventricular septal defect closure device for stroke prevention . 
 however , he was found to have a large thrombus attached to the device a year later . 
 we present a review of the various laa closure devices , importance of periodic surveillance via echocardiography and management options to prevent this complication . 
 also , the case highlights the importance of contrast - enhance echocardiography in diagnosis of laa closure device thrombus .