Failed endothelialisation of a percutaneous atrial septal defect closure device

Angioscopic Evaluation of Atrial Septal Defect Closure Device Neo-Endothelialization

Background

Current guidelines recommend at least 6 months of antithrombotic therapy and antibiotic prophylaxis after septal‐occluding device deployment in transcatheter closure of atrial septal defect. It has been estimated that it takes ≈6 months for complete neo‐endothelialization; however, neo‐endothelialization has not previously been assessed in vivo in humans.

Methods and Results

The neointimal coverage of septal occluder devices was evaluated 6 months after implantation in 15 patients by angioscopy from the right atrium. Each occluder surface was divided into 9 areas; the levels of endothelialization in each area were semiquantitatively assessed by 4‐point grades. Device neo‐endothelialization was sufficient in two thirds of patients, but insufficient in one third. In the comparison between patients with sufficiently endothelialized devices of average grade score ≥2 (good endothelialization group, n=10) and those with poorly endothelialized devices of average grade score <2 (poor endothelialization group, n=5), those in the poor endothelialization group had larger devices deployed (27.0 mm [25.0–31.5 mm] versus 17.0 mm [15.6–22.5 mm], respectively) and progressive right heart dilatation. The endothelialization was poorer around the central areas. Moreover, the prevalence of thrombus formation on the devices was higher in the poorly endothelialized areas than in the sufficiently endothelialized areas (Grade 0, 94.1%; Grade 1, 63.2%; Grade 2, 0%; Grade 3, 1.6%).

Conclusions

Neo‐endothelialization on the closure devices varied 6 months after implantation. Notably, poor endothelialization and thrombus attachment were observed around the central areas and on the larger devices.

Antiplatelet and Antithrombotic Therapy After Patent Foramen Oval and Atrial Septal Defect Closure

Pathologies of the atrial septum include different interatrial communications varying from patent foramen ovale (PFO) to actual defects. Atrial septal defects (ASDs) may be localized within the fossa ovalis such as the secundum type ASD or outside the region of fossa ovalis, such as the ostium primum defect and sinus venosus defect. Over the last decades, the percutaneous closure of interatrial shunts has become a feasible and safe method. During these procedures, the delicate balance between thrombotic risk, device sealing process and bleeding risk is crucial. In this review, we sought to describe current available data on the antiplatelet and antithrombotic management of patients after percutaneous ASD or PFO closure.

Barriers to Emergency Department Utilization of AFIB Protocol in Uncomplicated Lone AFIB Patients-Results from an Online Survey Study

Background

Historically, atrial fibrillation (AFIB) management has focused on rate control and anticoagulation, necessitating hospital admission. Recently, some emergency departments (EDs) have implemented protocols to avoid hospital admission when managing lone AFIB. Despite this recent trend, there is still reluctance toward the implementation of these protocols by some emergency physicians (EPs).

Objective

This study investigates barriers to implementation of ED AFIB protocols by surveying which aspects may impede their use.

Methods

To analyze the perceived barriers from EPs, we formulated a survey assessing the various components of ED AFIB management to identify which aspects might impede EP utilization. It was distributed as an email to large national ED physician group. Data was analyzed using descriptive means and weighted averages.

Results

Of 185 respondents (response rate 6.1%), 17.4% already had AFIB protocols in place at their home institutions and 82.6% did not. Majority opinion of largest barriers toward the implementation of AFIB protocols were the extended ED length of stay and discharge with unclear follow-up. There was little concern with chemical and electrical cardioversion and very limited concern with rate control and initiating oral anticoagulation. EPs supported placement in Observation for implementation and involvement of discharge planning to establish prescriptions and follow-up.

Conclusion

EP input regarding the development of ED AFib protocols will be essential in order to develop cost effective, convenient and safe methods of treatment. This survey of EP suggests that ED length of stay and insuring close outpatient follow up are key issues to address as protocols are designed.

Incomplete endothelialization of WatchmanTM Device: Predictors and Implications from Two Cases

Left atrial appendage occlusion (LAAO) is a promising alternative for stroke risk reduction in patients with non-valvular atrial fibrillation who are not suitable for long-term oral anticoagulation (OAC). Current practice mandates use of post-procedural OAC for 45 days after WatchmanTM placement during which complete device endothelialization is expected to occur. However, most of the evidence supporting this strategy stem from animal studies. Incomplete device endothelialization are often encountered after 6-weeks of procedure and its therapeutic implications are less clear. Here, we present two cases of incomplete endothelialization after 1.5- and 2-year of Watchman implantation. In one of the cases, we believe that an eccentric mitral regurgitation jet caused shearing force on the Watchman device and impeded with normal endothelialization. In the other case, we found a device related thrombus possibly favored by prothrombotic environment created by lack of endothelialization. Further studies are warranted to find predictors and better diagnostic tool of LAAO endothelialization.

Study of biodegradable occluder of atrial septal defect in a porcine model

Objective

To evaluate the safety and feasibility of a modified poly(l‐lactic acid) (PLLA) atrial septal defect (ASD) occluder.

Methods

Forty‐five piglets were divided into two groups: an experimental group (n = 27) and a control group (n = 18). The experimental group underwent percutaneous implantation of a modified PLLA ASD device while the control group underwent percutaneous implantation of a widely used metal ASD device. X‐ray imaging, transthoracic echocardiography (TTE), electrocardiogram (ECG), histopathology and electron microscopic examination were performed at 7 days, 1, 3, 6, and 12 months after implantation.

Results

Twenty‐seven experimental piglets and 18 control piglets were all successfully implanted with modified biodegradable and metal ASD devices, respectively. While both devices exhibited very good occluding effects, the modified PLLA ASD devices were completely endothelialized at 3 months after implantation, and the endothelialization appeared to be more complete compared to the control group. Degradation of the PLLA devices was noted at 12 months follow‐up with no loss of integrity at the atrial septum.

Conclusion

This animal model with implanting of the occluders was effective and not associated with complications. The modified PLLA ASD devices are more controllable and practical than our previous devices. The implanted devices demonstrated good endothelialization and degradability in short and moderate term follow‐up. Long‐term studies are now underway to further evaluate the biodegradability of this novel device.

Endocarditis and Incomplete Endothelialization 12 Years after Amplatzer Septal Occluder Deployment

A 4-year-old boy had a 15-mm atrial septal defect repaired percutaneously with use of an Amplatzer Septal Occluder. At age 16 years, he presented with a week's history of fever, chills, dyspnea, fatigue, and malaise. Cultures grew methicillin-sensitive Staphylococcus aureus. A transesophageal echocardiogram showed a 1.25 × 1.5-cm pedunculated mass on the left aspect of the atrial septum just superior to the mitral valve, and a smaller vegetation on the right inferior medial aspect of the septum. At surgery, visual examination of both sides of the septum revealed granulation tissue, the pedunculated mass, the small vegetation, and exposed metal wires that suggested incomplete endothelialization of the occluder. We removed the occluder and patched the septal defect. The patient returned to full activity after 4 months and was asymptomatic 3 years postoperatively. Our report reinforces the need for further investigation into prosthetic device endothelialization, endocarditis prophylaxis, and recommended levels of physical activity in patients whose devices might be incompletely endothelialized. In addition to reporting our patient's case, we review the medical literature on this topic.