Initial experiences with a novel biodegradable device for percutaneous closure of atrial septal defects: From preclinical study to first-in-human experience.

OBJECTIVE: To evaluate the feasibility, safety, and effectiveness of a novel, absorbable atrial septal defect (ASD) closure device made of poly-l-lactic acid (PLLA) in a swine model of ASD and for the first time in humans. METHODS: A preclinical safety study was conducted using a swine model of ASD. In a clinical setting, five pediatric patients underwent ASD closure with the PLLA device with fluoroscopic and transthoracic echocardiography guidance. The procedural results and clinical outcomes at 1 day, 30 days, 3 months, and 6 months after closure were analyzed. RESULTS: The 24- and 36-month follow-up results of the preclinical study demonstrated that the PLLA device exhibited good endothelialization and degradability in the swine model. In the clinical study, successful device implantation was achieved in all five patients (median age, 3.6 years; range, 3.1-6.5 years). The mean defect size was (13.6 ± 2.7) mm. Follow-up at 30 days, 3 months, and 6 months was completed in all five cases. The complete defect closure rates with no residual shunt at 30 days, 3 months, and 6 months follow-up were 60% (3/5), 80% (4/5), and 80% (4/5), respectively. No device dislodgement, significant aortic valve or mitral valve regurgitation, new onset cardiac arrhythmia, or other adverse events were reported. CONCLUSION: The study results demonstrated that it is feasible to implant the PLLA device for closure of small to medium sized ASDs without significant residual shunts or severe adverse events in humans. The PLLA device exhibited good endothelialization and degradability in the swine model at 24 and 36 months. Further studies to evaluate long-term safety and effectiveness with the device in a large cohort of patients are warranted.

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.

A Novel-Design Poly-L-Lactic Acid Biodegradable Device for Closure of Atrial Septal Defect: Long-Term Results in Swine.

OBJECTIVES: The aim of this study is to evaluate the long-term effectiveness and safety of a self-expandable, double-disk biodegradable device made of poly-L-lactic acid (PLLA) for closure of atrial septal defects (ASDs) in swine. METHODS: ASDs were created by transseptal needle puncture followed by balloon dilatation in 20 piglets. The experimental group comprised 18 animals, while the remaining 2 animals were used as controls. Effectiveness and safety were evaluated by rectal temperature, leukocyte count, chest radiography, electrocardiogram, transthoracic echocardiography (TTE), intracardiac echocardiography (ICE), and histologic studies. Animals were followed up at 1, 3, 6, and 12 months. RESULTS: An ASD model was successfully created in 19 animals; 1 piglet died during the procedure. The ASD diameters that were created ranged from 5 to 6.4 mm. Devices were successfully implanted in 17 animals. No animal died during the follow-up studies. Rectal temperatures and electrocardiograms were normal at follow-up, while leukocyte counts transiently increased from 1 to 6 months. Radiography, TTE, ICE, and macroscopic studies demonstrated that PLLA occluders were positioned well, with no shifting, mural thrombus formation, or atrioventricular valve insufficiency. Histologic evaluations showed that PLLA devices were partially degraded in the follow-up study. CONCLUSIONS: ASD closure with the novel PLLA biodegradable device is safe and effective. Longer-term studies are needed to evaluate long-term biodegradability.

Transcatheter Closure of Congenital Coronary Artery Fistulas with a Giant Coronary Artery Aneurysm in Children: Experiences from a Single Center.

BACKGROUND: Transcatheter closure of congenital coronary artery fistulas (CCAFs) is an alternative therapy to surgery; however, data regarding transcatheter closure for CCAF with a giant coronary artery aneurysm (CAA) in pediatric patients are still limited due to the rarity of the disease. We aimed to evaluate the efficacy and safety of transcatheter closure for CCAF with a giant CAA in a pediatric population at a single center. METHODS: Medical records of pediatric patients (<18 years old) who underwent transcatheter closure of CCAF with a giant CAA between April 2007 and September 2016 at Guangdong Cardiovascular Institute (Guangdong, China) were reviewed. RESULTS: Twelve patients (median age, 6.1 years; range, 1.9-11.0 years) underwent successful transcatheter closure procedures. One patient underwent closure at both the entry and exit points of the CAA, three patients underwent closure at the exit point of the CAA, and eight patients underwent closure at the entry point of the CAA. After a mean follow-up of 7.2 years (range, 0.5-9.8 years), one patient (with closure at the exit point of the CAA) underwent transcatheter re-intervention because of a significant residual shunt. She eventually underwent a surgical procedure due to aneurysm dilation after the second intervention. One patient experienced thrombus formation within the CAA after the procedure. Among those with closure at the entry point of the CAA, a mild-to-moderate residual shunt was detected in three patients. CONCLUSIONS: Transcatheter closure appears to be a safe and effective alternative therapy for CCAF with a giant CAA in the pediatric population. Closure at the entry point of the CAA, and closure at both the entry and exit points when feasible, may reduce the risk of postinterventional complications.

Platelet activation through the efficacy of aspirin in congenital heart disease patients undergoing transcatheter closure of atrial septal defects or ventricular septal defects.

OBJECTIVES: The aim of this study is to compare preoperative and postoperative conditions of GMP-140 concentration, the aggregation and activation of platelets in congenital heart disease patients undergoing transcatheter closure of atrial septal defects (ASDs) or ventricular septal defects (VSDs), and the appropriate dose of aspirin of patients after transcatheter closure. MATERIALS AND METHODS: Thirty-two consecutive patients with ASD (n=16) and VSD (n=16), as shown on transthoracic echocardiography and right heart catheter examination, were treated with a percutaneous catheter occlusion. The patients comprised 13 males and 19 females with a mean age of 25.6±9.15. Patients were randomly assigned into two groups within half an hour after ASD or VSD occlusion. Group A cases were treated with 3 mg/kg/day enteric-coated aspirin tablets for 6 months, while patients in group B received 5 mg/kg/day enteric-coated aspirin tablets for 6 months. RESULTS: The rates of platelet aggregation (PAG) in the immediate postoperative ASD/VSD occlusion were significantly higher than those in the preoperative ASD/VSD occlusion (adenosine diphosphate [ADP]-induced PAG: 64.98%±7.65% vs. 86.33%±6.54%, p<0.05; arachidonic acid [AA]-induced PAG: 62.92%±9.11% vs. 86.96%±6.90%, p<0.05, respectively). After treatment with aspirin, the GMP-140 levels presented a clearly defined downward trend in the immediate postoperative period (3 mg/kg/day aspirin: 18.30±3.42 vs. 13.37±1.80, p<0.05; 5 mg/kg/day aspirin: 18.30±3.42 vs. 13.41±1.60, p<0.05), but no obvious difference was observed considering the GMP-140 levels in the 4 days after occlusion (all p>0.05). CONCLUSION: Our study showed that the GMP-140 serum level and PAG were increased after ASD and VSD occlusion, and patients may have a trend of decreased GMP-140 serum levels after the ASD or VSD occlusion surgeries after the treatment with aspirin. Daily oral administration of 3 and 5 mg/kg/day aspirin can induce a significant decrease in PAG of patients after VSD/ASD occlusion.