Device-related Thrombus Formation Research Articles

Long-term outcomes after echocardiography versus fluoroscopy-guided left atrial appendage closure: Is there still a role for a simplified approach?

Left atrial appendage closure (LAAC) represents an alternative to oral anticoagulation for stroke prevention in patients with non-valvular atrial fibrillation (AF). While transoesophageal echocardiography is the current standard for guiding LAAC procedures, several centers have employed fluoroscopic guidance alone. However, data on long-term outcomes are lacking. A total of 536 patients with AF undergoing LAAC and with available data on long-term follow-up were included in the retrospective, single-center analysis. Outcomes of patients undergoing fluoroscopy-guided LAAC were compared with those undergoing echocardiography guided LAAC. Time-dependent analysis was performed with the Kaplan-Meier method. A total of 234 (44%) and 302 (56%) patients were treated with echocardiography and fluoroscopy guidance, respectively. Baseline characteristics did not differ between the two groups. Procedural success rates were high in both groups (97% of fluoroscopy vs. 98% of echocardiography guided procedures; p = 0.92) and rates of relevant peri-device leaks (p = 0.50) and device-related thrombus formation (p = 0.22) did not differ between groups. Median clinical follow-up time was 48 (IQR 19-73) months. Rates of all-cause mortality (p = 0.15, HR 0.83, CI 0.64-1.07) and stroke (p = 0.076, HR 2.23, CI 0.90-5.54) were comparable among groups. LAAC with fluoroscopy guidance alone is equally safe and leads to similar clinical outcome compared to LAAC with additional echocardiography guidance.

Challenges and advances in device-related thrombus in left atrial appendage occlusion.

Oral anticoagulation therapy (OAC) is a mainstay for mitigating stroke and other embolic events in patients with atrial fibrillation (AF). Despite the demonstrated efficacy of OAC in reducing events, many patients are unable to tolerate OAC due to bleeding risks. Left atrial appendage occlusion (LAAO) devices were developed as implantable technologies to moderate stroke risk in patients with intolerance to OAC. Despite clinical data supporting near-comparable protection against thromboembolic events with OAC, device-related thrombus formation has emerged as a critical complication following LAAO that remains a potential limitation to the safety and efficacy of LAAO. Improved biocompatibility of LAAO devices with fluoropolymers, a well-established stent-coating technology used to reduce thrombus formation and promote endothelialization, may optimize outcomes after LAAO.

Clinical outcome and intraprocedural characteristics of left atrial appendage occlusion: a comparison between single-occlusive plug-type and dual-occlusive disc-type devices.

Percutaneous interventional left atrial appendage occlusion (LAAO) is a reliable, safe, and effective alternative for stroke prevention in selected patients with atrial fibrillation (AF). In a retrospective observational study, 149 patients underwent LAAO between 2016 and 2022 at the Department of Cardiology of the Charité-Universitätsmedizin Berlin, Campus Virchow, with AF for prevention of thromboembolic complications. We compared patient characteristics, intraoperative details and postoperative outcomes between single-occlusive plug-type (SOPT) and dual-occlusive disc-type (DODT) devices. In all patients, the device implantation was successful. 60 patients received a SOPT occluder, including Watchman (35%) and Watchman FLX Occluders (65%), while 89 patients received a DODT occluder, including Amplatzer Cardiac Plug (37.1%), the Amplatzer Amulet (25.8%), and the LAmbre occluder (37.1%) systems. Procedure duration was significantly longer for DODT occluder implantation (49 ± 33 vs. 41 ± 25 min, p = 0.018). There were no in-hospital deaths or thromboembolic events reported after LAAO in both groups. Beyond that, a low rate of bleeding or access-side-related complications and pericardial tamponades were observed. Anticoagulation at discharge varied. About 60.8% of patients received dual antiplatelet therapy at hospital discharge, and 33.1% received direct oral anticoagulants. A 6-month follow-up was obtained in 85% of the patients. All implanted devices were in the desired position. However, in 5.7% of the patients, a device-related thrombus formation was detected in the SOPT group, while no thrombus was seen in the DODT group (p = 0.11). Thromboembolic events were noticed in 3.1%, without any difference between the device types. There was a statistically non-significant trend for less residual device leaks after SOPT vs. DODT implantation (no leak in 71.7% vs. 62.2%, p = 0.07; minor leaks <5 mm, 9.4% vs. 20.3%, p = 0.1). In the SOPT group, less bleeding complications were reported after LAAO (11.3% vs. 17.6%, p = 0.1). Our data suggest the safety and efficiency of LAAO with a very high procedural implantation success rate irrespective of the used LAA device. Furthermore, no relevant procedural or device-related complication occurred during the 6-month follow-up in all patients.

Late left atrial appendage closure device displacement and massive thrombus formation: a case report.

Background Left atrial appendage (LAA) closure with the WATCHMAN device is an alternative to anticoagulation therapy for the prevention of stroke in selected patients with atrial fibrillation (AF). Infrequently, left atrial (LA) device-related thrombus formation occurs and it is poorly understood. Thrombus formation due to incomplete covering of the LAA is even rarer and may occur within the first few months after device implantation.Case summary Here, we present a case of a 68-year-old male patient with permanent AF, drug- and hepatitis induced liver cirrhosis (CILD Score B), and prior aortic valve replacement. The patient had a history of percutaneous LAA closure using a WATCHMAN device. He developed massive peri-device leak and thrombus arising from the space between the device and appendage cleft 2 years after implantation. Because of the high bleeding risk with a HAS-BLED score of 5 points, surgery was chosen as the therapy of choice instead of long-term anticoagulation. The patient was discharged in good clinical condition and has been scheduled for a yearly follow-up.Discussion This case emphasizes the importance of choosing appropriately sized LAA occluder devices and planning for regular post-interventional follow-ups to minimize the risk of per-device leaks and thrombi.

Staged transcatheter closure for atrial septal defect and patent ductus arteriosus: a case report.

BackgroundAtrial septal defect (ASD) and patent ductus arteriosus (PDA) are both common congenital heart diseases, but the combination of these two cardiac defects is extremely rare, and the therapeutic strategy is controversial.Case summaryWe treated an adult patient with combined ASD and PDA, and safely attained a successful outcome with two-stage transcatheter closure, which is PDA closure preceding ASD closure, to prevent serious complications.DiscussionTranscatheter closure of one of the defects is now widely accepted as an alternative to surgical closure. In addition, adults with both ASD and PDA are better suited for transcatheter closure than surgical closure. One of the reasons is the difficulty to ligate the ductus arteriosus of an adult patient due to its friability and calcification. Meanwhile, simultaneous combined transcatheter closure of ASD and PDA can result in serious complications, such as thrombocytopenia and haemolysis, whose mechanism is considered to be the destruction of platelets and red blood cells by the residual shunt through implanted devices. Additionally, antiplatelet therapy that prevents device-related thrombus formation after ASD closure can possibly exacerbate thrombocytopenia and haemolysis. Therefore, the staged strategy is reasonable from the perspectives of antiplatelet therapy and haemodynamic changes.

Device-Related Thrombus After Left Atrial Appendage Occlusion With the Amulet Device

Left atrial appendage occlusion (LAAO) is increasingly used for stroke prevention in patients with atrial fibrillation who are considered unsuitable for a lifelong oral anticoagulant regimen. Recently, a single-centre study reported device-related thrombus formation in 16.7% of patients treated with the second-generation Amulet device (St. Jude Medical, St. Paul, MN, USA), presenting a potential major safety concern. As "real-world" data on device-related thrombus formation following LAAO with the Amulet occluder are scarce, we aimed to evaluate this outcome in a retrospective registry. Clinical and tranosesophageal echocardiography data after LAAO with the Amulet in consecutive patients from three centres were collated. Among 38 patients (mean age 75.8 years), mean (standard deviation) CHA2DS2-VASc and HAS-BLED scores were 4.4 (1.2) and 3.4 (0.9), respectively. All patients underwent successful device placement without procedure-related adverse events. The antithrombotic regimen at discharge consisted of dual antiplatelet therapy (DAPT) in 27 patients (71.1%), single antiplatelet therapy in 10 patients (26.3%), and no antithrombotic therapy in one patient (2.6%). Device-related thrombus was observed in one patient (2.6%) despite DAPT regimen. The outcome of this patient was uncomplicated after adjustment of oral anticoagulant therapy. No patients presented with a thromboembolic event following LAAO during a mean (standard deviation) follow-up of 15 (5) months. In this retrospective study, device-related thrombus formation with the second-generation Amulet device was rare and occurred at a rate similar to that of the previous device. Importantly, no patient experienced a device-related thromboembolic event during follow-up. Larger real-life studies are required to confirm the safety profile of this increasingly used device.

Safety and efficacy analysis of one-stop intervention for treating nonvalvular atrial fibrillation.

Nonvalvular atrial fibrillation (AF) is a common arrhythmia. The treatment strategy for AF mainly includes controlling symptoms and decreasing the rate of complications. Our study aimed to evaluate the safety and efficacy of combination treatment of catheter ablation and left atrial appendage (LAA) closure (one-stop intervention) in patients with nonvalvular AF. Thirty-four patients with symptomatic AF (mean CHA2 DS2 -VASc score 4.1 ± 1.3, mean HAS-BLED score 3.8 ± 1.2) were included. Patients first received radiofrequency-based left atrial ablation, and then the Watchman device (Boston Scientific, Natick, MA, USA) or AMPLATZER Cardiac Plug (ACP) (St. Jude Medical, Inc., St. Paul, MN, USA) was implanted for LAA closure. Follow-up was performed at 45 days and 3 months after LAA closure to assess for recurrence of AF and prevent stroke. Radiofrequency ablation and LAA closure were successful in 100% of patients without evidence of residual flow at the final transesophageal echocardiography evaluation. A Watchman device was implanted in 29 (85.3%) patients, and an ACP was implanted in five (14.7%) patients. No device-related thrombus formation or embolization was identified at the 45-day or 3-month follow-up. Serious complications, including death, transient ischemic attack, ischemic or hemorrhagic stroke, or major bleeding, were also not identified during the follow-ups. For symptomatic patients with nonvalvular AF and a high risk of stroke, the one-stop intervention is feasible, safe, and efficacious.

Incidence, Characteristics, and Clinical Course of Device-Related Thrombus AfterWatchman Left Atrial Appendage Occlusion Device Implantation in Atrial Fibrillation Patients.

This study investigated characteristics and clinical impact of device-related thrombus formation after Watchman device implantation in atrial fibrillation (AF) patients. Left atrial appendage occlusion using the Watchman device is an effective alternative to anticoagulation for stroke prevention in AF patients. However, device-related thrombus formation remains an important concern after Watchman implantation. From 2006 to 2014, 119 consecutive AF patients underwent Watchman implantation. Transesophageal echocardiographic (TEE) follow-up was scheduled at 45 days, at 6 months, and at 12 months after the procedure. The incidence, characteristics, and clinical course of device-related thrombus formation detected by TEE were assessed. Follow-up TEE identified thrombus formation on the Watchman device in 4 patients (3.4%). The prevalence of chronic AF was 100% in patients with thrombus, which was higher than that for patients without thrombus (40.0%). Deployed device size was numerically larger in patients with thrombus (29.3 ± 3.8 mm vs. 25.7 ± 3.2 mm, respectively). All patients with thrombus discontinued any of the anticoagulant/antiplatelet therapy which was required under the study protocol. After restarting or continuing warfarin and aspirin therapy, complete resolution of the thrombus was achieved in all patients at subsequent follow-up TEE. Warfarin therapy was discontinued within 6 months for all cases, and there was no thrombus recurrence. The mean follow-up duration was 1,456 ± 546 days, with no death, stroke, or systemic embolization events in patients with thrombus. AF burden, device size, and anticoagulant/antiplatelet regimens can be associated with device-related thrombus after Watchman device implantation. Short-term warfarin therapy was effective, and the clinical outcomeswere favorable.

First in vivo evaluation of a flexible self‐apposing left atrial appendage closure device in the canine model

Aimed to evaluate the feasibility of deployment and healing response of a novel transcatheter left atrial appendage (LAA) occlusion device in the canine model LAA occlusion is proposed to reduce the risk of stroke in atrial fibrillation patients Transseptal puncture and device deployment was guided under fluoroscopy and transesophageal echocardiography (TEE) in five dogs. First, a distal cylindrical bulb occluder was released and secured to the appendage wall with hooks. Subsequently, a proximal sail was unfolded, covering the LAA ostium. Rotational angiography, TEE, and histology outcomes were assessed 30 days following implantation Pre-operative TEE revealed the mean diameter of the LAA ostium to be 17.2 ± 1.6 mm with a depth of 18.5 ± 1.7 mm. The landing zone for the distal bulb was measured to be 12.8 ± 1.3 mm. The mean bulb diameter at implant was 16.8 ± 1.8 mm. Post-operative TEE showed adequate positioning and successful LAA occlusion with all implanted devices. Pericardial effusion requiring pericardiocentesis was seen in one animal following device implantation. At 30 days, TEE revealed full occlusion of all LAA ostia with the exception of a minimal peri-device leak (<3 mm) observed in one animal. No pericardial effusion or device-related thrombus formation was found at termination. Histological analysis confirmed circumferential occlusion of all appendages and complete neointimal coverage on the luminal aspect of the occluder The percutaneous delivery of a novel self-positioning LAA occlusion device is feasible and safe in a canine model. At 30 days, all devices displayed complete healing and occlusion of the LAA without any device related adverse events.

Feasibility and clinical efficacy of left atrial ablation for the treatment of atrial tachyarrhythmias in patients with left atrial appendage closure devices.

Left atrial appendage (LAA) closure devices have been introduced recently as an alternative for oral anticoagulation (OAC) in patients with nonvalvular atrial fibrillation (AF). Because of potential overlap of ablation target areas and the previously implanted LAA closure device, as well as potential complications such as mechanical damage to the device, left atrial (LA) ablation remains a subject of debate in these patients. We report on the feasibility and clinical efficacy of LA ablation after implantation of LAA closure devices. Eight patients (6 men; age 69 ± 8 years) with symptomatic paroxysmal AF (n = 5) or persistent AF (mean CHA2DS2-VASc score 3.6 ± 0.7, mean HAS-BLED score 3.6 ± 1.5) and previously implanted WATCHMAN (7 patients) or AMPLATZER Cardiac Plug (1 patient) LAA closure devices received radiofrequency-based LA ablation (4 via circumferential pulmonary vein isolation [CPVI], 4 via CPVI and additional LA linear lesions or complex fractionated atrial electrograms) after a mean of 201 days (range 41-756 days) after LAA closure. Successful LA ablation was achieved without device interference or periprocedural complications. After a mean of 503 days (range 113-1006 days), transesophageal echocardiography (TEE) was performed in all patients to assess for device-related complications. No device dislocation or leakage was observed. In 1 patient (12.5%), a device-related thrombus was found despite therapeutic OAC with dabigatran. Five patients (63%) remained in stable sinus rhythm, and no bleeding events or stroke occurred during a follow-up of 554 days (range 218-1006 days). LA ablation after LAA closure appears to be feasible. Device-related thrombus formation in 1 patient suggests the need for further TEE examinations after LA ablation after LAA closure device implantation.

Percutaneous closure of the left atrial appendage: a new option for the prevention of thromboembolic stroke

Percutaneous left atrial appendage (LAA) closure is an important therapeutic option for prevention of thromboembolic stroke in patients with atrial fibrillation (AF), especially when contraindications exist for oral anticoagulation. We aimed to evaluate our short-term results of LAA closure (initial experience) using the WATCHMAN LAA system. Eleven patients (8 men, 3 women; mean age 68.4±7.0 years) with nonvalvular AF, a high risk for cardioembolic stroke (mean CHADS2 score 2.6±1.2, mean CHA2DS2-VASc score 4.0±1.5), and contraindications to oral anticoagulation underwent percutaneous LAA closure using the WATCHMAN LAA system. All the procedures were performed under general anesthesia and fluoroscopy and transesophageal echocardiography (TEE) guidance. The patients were evaluated clinically (at 45 days and 6 months) and by TEE (at 45 days). The LAA was successfully occluded in all the patients (100%). The mean procedural and fluoroscopy times were 58.6±8.1 and 19.1±5.2 minutes, respectively. The mean diameter of the LAA ostium was measured as 20.4±3.8 mm by TEE. The mean device size was 24.6±3.8 mm. The mean hospital stay was 1.7±0.9 days. Follow-up TEE showed closure of all LAA orifices without device-related thrombus formation. Two patients (18.2%) had minimal peri-device leaks (<3 mm). None of the patients experienced major adverse events during a median follow-up of 90 days (interquartile range 60-185 days). Our initial experience suggests that percutaneous LAA closure with the WATCHMAN LAA system is safe and feasible, with favorable short-term clinical outcomes.

Left atrial appendage closure with Amplatzer cardiac plug for stroke prevention in atrial fibrillation: Initial Asia‐Pacific experience

Left atrial appendage (LAA) is the main source of left atrial thrombus that causes stroke in patients with non-valvular atrial fibrillation (NVAF). This study reported the initial safety, feasibility, and 1-yr clinical outcomes following AMPLATZER cardiac plug (ACP) implantation in Asia-Pacific region. Twenty NVAF patients (16 males, age 68 ± 9 yr) with high risk for developing cardioembolic stroke (CHADS(2) score: 2.3 ± 1.3) and contraindications to warfarin received ACP implants from June 2009 to May 2010. Patients received general anesthesia (n = 9) or controlled propofol sedation (n = 11) and the procedures were guided by fluoroscopy and transesophageal echocardiography (TEE). Clinical follow-up was arranged at 1 month and then every 3 months after implantation, whereas, a TEE was scheduled at 1 month upon completion of dual anti-platelet therapy. The LAA was successfully occluded in 19/20 patients (95%) at two Asian centers. One procedure was abandoned because of catheter-related thrombus formation. Other complications included coronary artery air embolism (n = 1) and TEE-attributed esophageal injury (n = 1). The median procedural and fluoroscopic times were 79 (IQR: 59-100) and 18 (IQR 12-27) minutes, respectively. The mean size of implant was 23.6 ± 3.1 mm. The average hospital stay was 1.8 ± 1.1 days. Follow-up TEE showed all the LAA orifices were sealed without device-related thrombus formation. No stroke or death occurred at a mean follow-up of 12.7 ± 3.1 months. Our preliminary data suggested LAA closure with ACP is safe, feasible with encouraging 1-yr clinical outcomes. Further large-scaled trials are needed to confirm the efficacy of this device.

Initial Worldwide Experience With the WATCHMAN Left Atrial Appendage System for Stroke Prevention in Atrial Fibrillation

This study assessed the feasibility of implanting a device in the left atrial appendage (LAA) in patients with atrial fibrillation (AF) to prevent thromboembolic stroke. Meta-analyses confirmed that in cases of left atrial thrombus in nonrheumatic AF patients approximately 90% of them are in the LAA. The WATCHMAN Left Atrial Appendage System (Atritech Inc., Plymouth, Minnesota) is a nitinol device implanted percutaneously to seal the LAA. Patients were followed by clinical and transesophageal echocardiography at 45 days and 6 months with annual clinical follow-up thereafter. Sixty-six patients underwent device implantation. Mean follow-up was 740 +/- 341 days. At 45 days, 93% (54 of 58) devices showed successful sealing of LAA according to protocol. Two patients experienced device embolization, both successfully retrieved percutaneously. No embolizations occurred in 53 patients enrolled after modification of fixation barbs. There were 2 cardiac tamponades, 1 air embolism, and 1 delivery wire fracture (first generation) with surgical explantation but no long-term sequelae for the patient. Four patients developed a flat thrombus layer on the device at 6 months that resolved with additional anticoagulation. Two patients experienced transient ischemic attack, 1 without visible thrombus. There were 2 deaths, neither device related. Autopsy documented a stable, fully endothelialized device 9 months after implantation. No strokes occurred during follow-up despite >90% of patients with discontinuation of anticoagulation. Preliminary data suggest LAA occlusion with the WATCHMAN System to be safe and feasible. A randomized study is ongoing comparing oral anticoagulation with percutaneous closure.

Patent foramen ovale closure in patients with cryptogenic thrombo-embolic events using the Cardia PFO occluder

We report our experience with three generations of the Cardia patent foramen ovale (PFO) occluder in patients with cryptogenic thrombo-embolic events (TE). Between 1998 and 2004, interventional PFO closure was attempted in 403 patients. Prior to PFO closure, 605 TE occurred, translating into an annual incidence of 3.1%. PFO closure was successful in all patients. Peri-procedural complications occurred in eight patients (2.0%). At 6 months follow-up, residual shunt was present in 10.8% of patients. Transient thrombi developed on 10 devices (predominantly generation II) and asymptomatic wire fractures were detected in 14 cases (generation I and II). The annual incidence of recurrent TE was 2.0% (n=13). Atrial septal aneurysm and prior device-related thrombus formation were identified as predictors of recurrent TE. Owing to technical improvements and modified adjunctive pharmacotherapy, the rate of thrombus formation has declined and wire fractures are virtually absent in generation III devices. The overall rate of recurrent TE is reduced by transcatheter PFO closure with the Cardia PFO occluder, and seems comparable to recurrence rates reported for other devices used for this purpose.

LOW-MOLECULAR-WEIGHT HEPARIN FOR ANTICOAGULATION OF AXIAL FLOW PUMPS

Purpose. Bleeding and thromboembolism are major complications during mechanical support. Typically, warfarin and aspirin 2 dipyrid-amole are used to prolong clotting times and suppress platelet function in patients with axial flow pumps. We report 2 patients assisted with axial flow pumps using LMWH as sole anticoagulant treatment in addition to platelet inhibition. Methods. Two patients received INCOR Berlin Heart® as destination therapy. The system uses a hearing-less impeller and Carmeda® BioActive Surface coating of all blood-contacting surfaces. Anticoagulation was started early after surgery using IV heparin (anti-Xa activity 0.3–0.4 IU/L). Aspirin was started at 250 mg/d and was subsequently adjusted to in vitro platelet function tests. Coumadin was started after chest drains removal (INR 2.5–3.5). Both patients presented major bleeding complications 2 months after implantation. Coumadin was withheld and replaced by enoxaparine (anti-Xa 0.5–0.6 IU/L). Results. None of the patients experienced any bleeding or thromboembolic complication 72 and 101 days after LMWH initiation. Suspicion of device-related thrombus formation prompted us to increase LMWH (anti-Xa activity 0.8–1.O IUIL). Clopidogrel was added to aspirin. Repeated laboratory testing showed a consistent anticoagulation effect of LMWH treatment. Conclusion. Anticoagulation using LMWH appears to he a safe option for patients assisted with the INCOR Berlin Heart® axial flow pump presenting a contraindication for antivitamin K therapy.