Ventricular Septal Defect Occluder Research Articles

An observational study of symmetrical VSD occluder for transcatheter closure of ruptured sinus of Valsalva aneurysm.

This study evaluated the immediate and 1-year postoperative outcomes of 14 patients with ruptured Valsalva aneurysmal sinus (RSVA) using symmetric ventricular septal defect (VSD) occluder for transcatheter closure (TCC). The sites of rupture were from the non-coronary sinus to the right atrium (RA) in 10 cases (71.4%), the right coronary sinus (RCS) to the RA in 3 cases (21.4%) and the RCS to the right ventricle in 1 case (7.2%). The defects (5-11 mm) were closed with a symmetrical VSD device. During the follow-up (12 months), the enlarged heart of the patients had significantly shrunk and the NYHA improved after closure. In 1 case, a moderate residual shunt was present and the patient suffered from hemolysis at 2 h after the operation, and 1 patient was transferred to surgery for aortic regurgitation 1 year after the initial treatment of RSVA. In conclusion, the TCC of RSVA with the China made symmetrical VSD occluder is safe and effective.

Percutaneous Closure of Hemodynamically Significant Postoperative Residual Ventricular Septal Defects.

The experience with percutaneous closure of postoperative residual ventricular septal defects (VSDs) is expanding with improved device technology and techniques. To report our experience with percutaneous closure of residual VSDs after cardiac surgeries. Retrospective clinical data review of patients who had percutaneous closure of postoperative residual VSDs at our institution between 2010 and 2022. Patients' demographics, procedural, and follow-up data were looked at. Twelve patients (50% males) with a median age of 9.2years (range 0.9-22) were identified. Baseline surgeries were 8 tetralogy of Fallot corrections, 2 pulmonary bandings for large muscular VSD (mVSD) including 1 coarctation repair, 1 atrioventricular septal defect repair, 1 sub-aortic membrane resection-induced iatrogenic VSD, 1 isolated VSD closure, and 1 additional mVSD. Median duration between baseline surgery and percutaneous VSD closure was 2.2years (range 0.2-8.3). Residual VSD shunting was secondary to surgical patch leakage in 8/12 patients. The median angiographic defect diameter was 6.8mm (range 4.8-14). The defect was balloon-calibrated in 3/12 patients. Defects were tackled retrogradely in 3/9 patients. Amplatzer Membranous VSD occluder (n = 1), Lifetech Multifunctional (n = 5), Membranous (n = 1) and muscular VSD occluders (n = 2) and Occlutech Membranous (n = 1) and Muscular (n = 2) VSD occluders were used. The procedure was successful in 10/12 patients. Two devices embolized to the pulmonary artery and were snare-retrieved. Both patients were referred for surgery. The median follow-up was 1.3years (range 0.1-12). Six-month ultrasound showed one trivial residual shunt and one mild right ventricular outflow obstruction. One patient is receiving targeted therapy for pulmonary hypertension at 2years of follow-up. Transcatheter closure of postoperative residual VSDs is a feasible yet challenging intervention. Procedural complications can be encountered.

Word of caution: silent late device embolisation after perimembranous ventricular septal defect closure in a 6-Kg infant.

We report on a 6-month-old infant (6 Kg/ 64 cm) with perimembranous ventricular septal defect (absent sub-aortic rim, 10 mm left ventricular entry, and 4 and 6 mm right ventricular exists) and successful retrograde closure using an 8x6 mm KONAR-MF™ VSD occluder (Lifetech, China). Immediate and 48 hours post-procedure ultrasounds showed an accurately positioned device and two jets of mild-to-moderate residual shunts. At the 2-week follow-up, the device did not change position and the shunt was stable and intra-prosthetic. The scheduled 3-month follow-up was skipped for familial reasons. The patient came back without alarming symptoms for the regular 6-month follow-up, and the device was found embolised to the left pulmonary artery. The device was retrieved surgically, and the defect was patch-closed with excellent outcomes. There was a pseudoaneurysm involving the tricuspid valve chordae and the device was endothelialized partially on one edge suggesting that embolization occurred somewhere between 3 months and 6 months post-operative. Defects with compromised anatomies should be closed surgically to avoid suboptimal results, especially in small infants.

Systemic venous anomalies in a child with a vein of Galen

ABSTRACT We describe our findings in a child with a vein of Galen malformation, in whom the right superior caval and the azygos veins drained into the roof of the morphologically left atrium. A persistent left superior caval vein drained into the morphologically right atrium through the coronary sinus. The additional presence of dual brachiocephalic veins permitted the deployment of a multifunctional ventricular septal defect occluder device to occlude the right superior caval vein, correcting the right-to-left shunt. This also prevented azygos venous drainage into the left atrium.

Safety and efficacy of Amplatzer duct occluder II and konar-MF™ VSD occluder in the closure of perimembranous ventricular septal defects in children weighing less than 10 kg

IntroductionDevice closure of perimembranous ventricular septal defects (pmVSD) is a successful off-label treatment alternative. We aim to report and compare the outcomes of pmVSD closure in children weighing less than 10 kg using Amplatzer Duct Occluder II (ADOII) and Konar-MF VSD Occluder (MFO) devices.MethodsRetrospective clinical data review of 52 children with hemodynamically significant pmVSD, and sent for transcatheter closure using ADOII and MFO, between January 2018 and January 2023. Baseline, procedural, and follow-up data were compared according to the implanted deviceResultsADOII devices were implanted in 22 children with a median age of 11 months (IQR, 4.1–14.7) and weight of 7.4 kg (IQR, 2.7–9.7). MFO devices were implanted in 30 children with a median age of 11 months (IQR, 4.8–16.6) and weight of 8 kg (IQR, 4.1–9.6). ADOII were implanted (retrograde, 68.1%) in defects with a median left ventricular diameter of 4.6 mm (IQR, 3.8–5.7) and right ventricular diameter of 3.5 mm (IQR, 3.1–4.9) while MFO were implanted (antegrade, 63.3%) in defects with a median left ventricular diameter of 7 mm (IQR, 5.2–11.3) (p > 0.05) and right ventricular diameter of 5 mm (IQR, 2.0, 3.5–6.2) (p < 0.05). The procedural and fluoroscopy times were shorter with the MFO device (p < 0.05). On a median follow-up of 41.2 months (IQR, 19.7–49.3), valvular insufficiency was not observed. One 13-month-old child (6.3 kg) with ADOII developed a complete atrioventricular heart block (CAVB) six months postoperative and required pacemaker implantation. One 11-month-old child (5.9 kg) with MFO developed a CAVB 3 days postoperative and the device was removed. At 6 months post-procedure, only one child with MFO still experiences a minor residual shunt. There was one arterio-venous fistula that resolved spontaneously.ConclusionBoth the MFO and ADOII are effective closure devices in appropriately selected pmVSDs. CAVB can occur with both devices. The MFO is inherently advantageous for defects larger than 6 mm and subaortic rims smaller than 3 mm. In the literature, our series represents the first study comparing the mid-term outcomes of MFO and ADOII devices in children weighing less than 10 kg.

A Retrospective Study in Occluding Sub-arterial Ventricular Septal Defect.

To assess the safety and effectiveness of utilizing eccentric occlusion for the treatment of sub-arterial ventricular septal defects, we performed a retrospective study on the classification and analysis of relevant cases. A total of 105 patients with a minimally invasive incision were enrolled in this study, from April 2018 to September 2022. All patients underwent treatment of transthoracic sub-arterial ventricular septal defect occlusion. We analyzed the causes of closure failure, indication, and complication. Briefly, the closure device was successfully implanted in 78 cases (74.2%) with a mean age of 31.4 ± 31.8months, VSD size of 4.3 ± 0.9mm, and device size of 6.0 ± 1.1mm. However, 27 cases (25.8%) required cardiopulmonary bypass due to failure of occlusion. The reasons for failure included 13 cases with worsened aortic regurgitation, two cases with worsened aortic valve prolapse, one case with worsened mitral regurgitation, eight cases with significant residual shunt, and three cases with deviated occlusion morphology. During the 1-36-month follow-up visit, no cases experienced displacement of the eccentric umbrella, shedding, or arrhythmia. All residual shunts resolved during the visit. We concluded that occlusion for sub-arterial VSD has sufficient security and feasibility, under the strict control of surgical indications, appropriate choice of occluder and precise perioperative management.

S3397 Endoscopic Closure of a Gastrocutaneous Fistula With the Application of 2-octyl-cyanoacrylate Glue With Ventricular Septal Defect Occluder

S3397 Endoscopic Closure of a Gastrocutaneous Fistula With the Application of 2-octyl-cyanoacrylate Glue With Ventricular Septal Defect Occluder

Clinical evaluation of ventricular septal defect occlusion device for the treatment of postoperative bronchopleural fistula

Bronchopleural fistula is an abnormal sinus tract that forms between the bronchus and the thoracic cavity. It is most commonly caused by thoracic surgery. Patients often have severe pulmonary and thoracic infections, which seriously affect the quality of life and survival rate. Most of these patients do not have a second operation chance, so the bronchopleural fistula becomes a thorny problem in the clinical practice. The clinical data of 9 patients with postoperative bronchopleural fistula admitted to Anhui Provincial Chest Hospital were reviewed and analyzed. We analyzed and summarized the clinical experience of successful occlusion with a ventricular septal defect(VSD) device, which provided a potentially effective treatment for postoperative bronchopleural fistula.

Feasibility of Transatrial Access for Epicardial Ablation: Evaluation of 2 Different Techniques in Swine

BackgroundThe subxiphoid pericardial access is technically difficult and has a considerable rate of complications, thus transatrial access may be an alternative. ObjectivesThis study sought to assess the feasibility and safety of this strategy regarding periprocedural period and after 1-week follow-up. MethodsThe investigators performed epicardial mapping through transatrial puncture in 20 swine. Animals were divided into group A, in which aspiration of the sheath was performed to maintain negative pressure after the withdraw of the catheters, and group B, in which a device (Konar-MF VSD Occluder) was delivered to occlude the right atrial appendage perforation. Bleeding was investigated immediately and 1 week after. ResultsAccess was safe in 19 of 20 animals (95%) with small amount of bleeding (6.4 ± 6 mL). In group A (n = 10), 1 animal presented hemopericardium right after the puncture. In the other 9, epicardial ablation was performed and 60.0 ± 28.0 mL of blood was aspirated without events. After 1 week, fibrin-hemorrhagic pericarditis was identified in 3 animals. In group B (n = 10), reaching the epicardial surface was possible in all animals. An adequate position of the prosthesis was obtained in 90% (9 of 10). One death occurred in the immediate postoperative period, secondary to pneumothorax. After 1 week, postmortem analysis showed absence of pericardial bleeding and a normal-appearing pericardium in the 8 animals with adequate prosthesis position. ConclusionsTransatrial access allows epicardial mapping and ablation. Sheath removal after negative pressure contributes to achieving acute bleeding control but does not prevent its occurrence. The use of the device prevents bleeding and hemorrhagic pericarditis.

Long-term outcomes of percutaneous closure of ventricular septal defects in children using different devices: A single centre experience from Egypt

BackgroundThe feasibility of percutaneous closure ventricular septal defects (VSD) in children has been previously proven. However, data on long-term outcomes are limited. We aim to evaluate the long-term outcome of our experience with percutaneous closure of VSD using various occluders.MethodsRetrospective institutional analysis of children who underwent transcatheter closure of perimembranous and muscular VSDs between September 2012 and February 2020. Patient demographics, procedural, and long-term follow-up data were comprehensively analyzed. Patients who lost to follow-up within two years post-procedure were excluded.ResultsWe identified 75 patients (54.7% males) with a median of 66 months (IQR, 46–96). The closure success rate at one year was 95.7%. Complete heart block was detected in two patients early post-procedure and resolved with steroids. The VSDs were perimembranous (52%), muscular (33.33%), and residual (14.67%). Implanted devices were Pfm Nit-Occlud LeˆVSD Coil (42.7%), HyperionTM VSD Muscular Occluder (28%), Amplatzer VSD muscular occluder (10.7%), Amplatzer Duct Occluder (14.7%), Occlutech Muscular VSD Occluder (2.7%), and Amplatzer Duct Occluder II (1.3%). No new arrhythmia or valve regurgitation was detected after two years post-procedure. Persisted complications on long-term follow-up included: residual shunting in 3(4%), mild tricuspid regurgitation in 2(2.7%), and aortic regurgitation in 2(2.7%), with one immediate post-catheterization mild aortic regurgitation worsened during follow-up, requiring surgical repair of VSD three years after device implantation. No deaths were reported.ConclusionLong-term outcomes of pediatric transcatheter VSD closure using different devices are satisfactory. Post-procedural adverse events are limited, but long-term surveillance is necessary to monitor their progression.

Comparative outcomes of two competitive devices for retrograde closure of perimembranous ventricular septal defects.

Retrograde closure of perimembranous ventricular septal defects (pmVSDs) is a well-established procedure. However, interventionists are still looking for the best closure device. We performed a single-center retrospective review of 5-year-experience (from July 2015 to July 2020) with retrograde closure of pmVSDs using AmplatzerTM Duct Occluder II (ADOII) and KONAR-MF™ VSD occluder (MFO). Deficient sub-aortic rim (SAR) (≤2.5 mm for MFO and ≤3 mm for ADOII) was an exclusion criterion in defects with a diameter ratio (right-side exit/left-side entry) > 0.5. We identified 77 patients (57.1% males) with a median age of 4.3 years (IQR, 2.2-8.3) and a median weight of 16 kg (IQR, 11.2-24.5). 44 (57.1%) defects (22.7% with deficient SARs) with a median left-side defect diameter of 8.7 mm (IQR, 5.7-10) were closed with ADOIIs. 33 (42.9%) defects (51.5% with deficient SARs) with a median left-side defect diameter of 10.8 mm (IQR, 8.8-13.5) were closed with MFOs. One 7/5 MFO was removed before release and upsized to a 12/10 MFO. Implantation success rate was 100% with ADOII and 90.9% with MFO devices. Two MFOs were snare-recaptured after embolization, and one 9/7 MFO was snare-retrieved for a new onset of grade-2 aortic regurgitation that persisted afterward. Median follow-up was 3.3 years (IQR, 2.1-4.2) for ADOII and 2.3 years (IQR, 1.7-2.5) for MFO. No permanent heart block or death occurred. Freedom from left ventricular dilation was 94.62% at 36 months of follow-up. Freedom from residual shunt was 90.62% for MFO and 89.61% for ADOII at 24 months of follow-up. One 2.6-year-old patient with baseline mild aortic valve prolapse and trivial aortic regurgitation developed a grade-2 aortic regurgitation after 9/7 MFO implantation. He was treated surgically after two years without device extraction. One new grade-2 asymptomatic tricuspid regurgitation persisted at the last follow-up in the ADOII group. ADOII and MFO are complementary devices for effective retrograde closure of pmVSDs in children, including defects with absent or deficient SAR. ADOII is limited to smaller defects but offers a lower profile and a flexible left-side disk for better maneuverability over the aortic valve during retrograde implantation.

Tran Catheter Closure of Ventricular Septal Defects (VSD): Preliminary Results in Children Weighing 5kg or Less

<i>Aim: </i>This study aims to evaluate feasibility and complications of device closure of ventricular septal defect (VSD) in children weighing 5kg. <i>Methods:</i> Between March 2018 and March 2021, total 15 patients with Ventricular Septal Defect (VSD) weighing 5Kg or less were taken to Cath lab for percutaneous VSD closure out of which 13 (86%) had successful transcatheter closure and 2 (14%) cases were unsuccessful and subsequently send for surgical closure. All of these13 patients under went transcatheter closure of VSD using either a Amplatzer duct occluder1, Amplatzer duct Occluder 2 or Amplatzer Muscular VSD Occluder. A retrospective review of the results and related complications was done. <i>Results:</i> Among these 15 patients, 7 were females, 6 were male and the mean age was 8.5 (4-16month. The mean weight in this study was 4.46Kg (2.3-5Kg). Mean VSD size was 4.5 (3-10mm), 9 patients had VSD sizes between 3to5mm, 3 had between5-10 mm and 1 with more than 10mm. Among types of VSD, 9 cases were having Perimembranous, 1 was upper muscular, 1was mid while 1was lower muscular and only 1 had outlet muscular VSD. Amplatzer Duct Occluder (ADOI) was used in 2 cases, 9 were closed with Amplatzer Duct Occluder (ADO2) and 2 were selected for closure with Amplatzer Muscular VSD Occluder. Transthoracic Echocardiography (TTE) in immediate post intervention period revealed all these devices in situ with no or minimal residual flow which subsided within 24 hours period. As far as complications are concerned, we had one device embolization noted in our study. Tricuspid regurgitation (TR) was noted at the time of discharge in 4 patients but subsided after 48 hours while trivial aortic regurgitation was noted (AR) only in one case which is under close follow up and not increasing in severity after 6 months follow-up. <i>Conclusions</i>: Transcatheter closure of VSD in children 5kg or less is feasible and safe alternative to surgical VSD closure.

Closure of transcatheter ventricular septal defect using LifetechTM Konar-MF Occluder in children weighing less than 10 kilograms: mid-term results, a tertiary single center experience.

Transcatheter closure of medium and large ventricular septal defects (VSDs) in young children is limited due to the use of over-sized devices that can cause hemodynamic instability and arrhythmia. In this study, we aimed to retrospectively evaluate the safety and efficacy of the device in the mid-term in children weighing less than 10 kg whose transcatheter VSD was closed only with the Konar-MFO device. Among 70 children whose transcatheter VSD was closed between January 2018 and January 2023, 23 patients weighing less than 10 kg were included in the study. Retrospectively, the medical records of all patients were reviewed. The mean age of the patients was 7.3 (4.5-26) months. 17 of the patients were females, 6 of them were males, F/M: 2.83. The average weight was 6.1 (3.7-9.9) kg. The mean the pulmonary blood flow/ systemic blood flow (Qp/Qs) was 3.3 (1.7-5.5). The mean defect diameter was 7.8 mm (5.7-11) for the left ventricle (LV) side, and 5.7 mm (3-9.3) for the right ventricle (RV) side. Based on the utilized device dimensions, the measurements on the LV side were recorded as 8.6 mm (range 6-12), while those on the RV side were recorded as 6.6 mm (range 4-10). Antegrade technique was applied to 15 (65.2%) patients and retrograde technique was applied to 8 (34.8%) patients in the closure procedure. The procedure success rate was 100%. The incidence of death, device embolization, hemolysis, or infective endocarditis was zero. Perimembranous and muscular VSDs in children under 10 kg can be successfully closed under the management of an experienced operator with the Lifetech Konar-MFO device. This is the first study in the literature to evaluate the efficacy and safety of the device in children under 10 kg in whom only Konar-MFO VSD occluder device is used for transcatheter VSD closure.

Results and cost analysis of Amplatzer® Ductal Occluder-ii, Nit Occlud® Lê Coil, and Konar-MF® ventricular septal defect occluder for percutaneous ventricular septal defect closure

Background: A number of devices have been used for percutaneous closure of ventricular septal defect (VSD) in this era of Jaminan Kesehatan Nasional. The aim of this study is to describe the differences in results and cost analysis of various devices used for percutaneous closure of VSD. Patients and methods: This retrospective study was done in 88 patients underwent transcatheter VSD closure between May 2015-April 2019 at Sanglah Hospital Indonesia (regional 2, medical service level 3). Three types of devices were compared: Amplatzer® Ductal Occluder-II (ADO-II®), Nit Occlud® Lê Coil, and KONAR-MF® VSD Occluder (MFO®). Total cost and hospital earnings from Indonesia Case Based Groups (INA-CBG’s), procedure outcomes, and complications were recorded. Statistical analysis was done using Kruskal-Wallis test and Mann-Whitney test. Results: Successful deployment of ADO-II® Nit Occlud, ® Lê Coil, and MFO® were 33, 32, and 21 cases respectively. Procedure and fluoroscopy time were shorter in ADO-II® compared to other groups (p=0.001 and 0.003). Complication rate was equally similar in all groups. Real cost was higher in Nit Occlud® Lê Coil compared to other groups. Negative hospital earnings was smaller in ADO-II® and MFO® groups than Nit Occlud® Lê Coil group (median -1,633,850 vs -14,006,600 vs -1,247,900 respectively), adjustment for length of stay found similar result. Adjustment by admission class found no difference of hospital earnings. Conclusion: The ADO-II® and MFO® have the smallest cost. Considering the cost-effectiveness and feasibility, ADO-II® can be chosen in small defects (&lt;6 mm), meanwhile MFO® in larger defects. All devices described have equal success rate and complications.

Transcatheter closure of large postinfarct ventricular septal defect: Initial results of prototype Occlutech® device including the first-in-human.

Postinfarct ventricular septal rupture is a serious complication in delayed or failed reperfusion with a grim prognosis. The optimal timing and treatment option remain debatable in the absence of randomized controlled trials. Percutaneous device closure is a well-reported and less invasive treatment option but recent imaging studies indicate that majority of defects are too large to be adequately covered by the currently Conformite Europeenne and Food and Drug Administration approved occluder devices. Six patients presented with large and complex postinfarct ventricular septal ruptures, considered unsuitable for the Amplatzer post-infarct ventricular septal defect Occluder, sowere treated using the prototype Occlutech® 36 mm PI-VSD occluder, including the first-in-human use. The prototype device was successfully deployed in all patients with satisfactory immediate results and shunt reduction. Three patients (50%) in cardiogenic shock did not survive beyond discharge, of which two were complicated by device dislodgement or embolization. Percutaneous closure of large postinfarct ventricular septal ruptures is possible using newer device with a wider coverage. Further device refinement is necessary to improve treatment outcomes.

Bronchoscopic interventions for bronchopleural fistulas

Bronchopleural fistula is a potentially fatal disease most often caused after pneumonectomy. Concomitant problems such as pulmonary infection and respiratory failure are typically the main contributors to patient mortality because of the improper contact between the bronchial and pleural cavity. Therefore, bronchopleural fistulas need immediate treatment, which requires the accurate location and timely closure of the fistula. Currently, bronchoscopic interventions, because of their flexibility and versatility, are reliable alternative therapies in patients for whom surgical intervention is unsuitable. Possible interventions include bronchoscopic placement of blocking agents, atrial septal defect (ASD)/ventricular septal defect (VSD) occluders, airway stents, endobronchial valves (EBVs) and endobronchial Watanabe spigots (EWSs). Recent developments in mesenchymal stem cells (MSCs) transplantation technology and three-dimensional (3D) printed stents have also contributed to the treatment of bronchopleural fistula, but more research is needed to investigate the long-term benefits. This review focuses on the effectiveness of various bronchoscopic measures for the treatment of bronchopleural fistula and the directions for future development.

Percutaneous Transcatheter Closure of Congenital Ventricular Septal Defects.

Ventricular septal defects (VSDs) are the most common kind of congenital heart disease and, if indicated, surgical closure has been accepted as a gold-standard treatment. However, as less-invasive methods are preferred, percutaneous device closure has been developed. After the first VSD closure was performed percutaneously by Lock in 1988, both techniques and devices have developed consistently. A perventricular approach for closure of muscular VSD in small patients and the closure of perimembranous VSD using off-label devices are key remarkable developments. Even though the Amplatzer membranous VSD occluder (Abbott) could not be approved for use due to the high complete atrioventricular conduction block rate, other new devices have shown good results for closure of perimembranous VSDs. However, the transcatheter technique is slightly complicated to perform, and concerns about conduction problems after VSD closure with devices remain. There have been a few reports demonstrating successful closure of subarterial-type VSDs with Amplatzer devices, but long-term issues involving aortic valve damage have not been explored yet. In conclusion, transcatheter VSD closure should be accepted as being as effective and safe as surgery but should only be performed by experienced persons and in specialized institutes because the procedure is complex and requires different techniques. To avoid serious complications, identifying appropriate patient candidates for device closure before the procedure is very important.

4D Printing of Overall Radiopaque Customized Bionic Occlusion Devices.

Percutaneous closure of ventricular septal defect (VSD) can effectively occlude abnormal blood flow between ventricles. However, commonly used Nitinol occlusion devices have non-negligible limitations, such as nondegradability leading to life-threatening embolization; limited device size predisposing to displacement and wear; only a few radiopaque markers resulting in inaccurate positioning. Nevertheless, the exploration of customized, biodegradable, and overall radiopaque occluders is still vacant. Here, overall radiopaque, biodegradable, and dynamic reconfigurable 4D printed VSD occluders are developed. Based on wavy bionic structures, various VSD occluders are designed and manufactured to adapt to the position diversity of VSD. The customized configuration, biocompatibility, and biodegradability of the developed 4D printed bionic occluders can eliminate the series of complications caused by traditional occluders. The overall radiopacity of 4D printed VSD occluders is validated ex vivo and in vivo, whereby accurate positioning can be assured. Notably, the preparation strategies for 4D printed occluders are scalable, eliminating the barriers to mass production, and marking a meaningful step in bridging the gap between modeling and clinical application of 4D printed occlusion devices. This work opens attractive perspectives for the rapid manufacturing of customized intelligent medical devices for which overall radiopacity, dynamic reconfigurability, biocompatibility, and biodegradability are sought.

A fully degradable transcatheter ventricular septal defect occluder: Towards rapid occlusion and post-regeneration absorption

Degradable heart occluders are a promising replacement for currently clinically used non-degradable ones without concerns about the complications caused by the persistent residue of a foreign implant. However, the inherent mechanical properties of degradable occluders are poor and decline with material degradation, leading to a preference for a long degradation period upon designing a degradable heart occluder. This configuration can lower the risk of occluder dislodgement but reduce the benefits of degradable implants over their non-degradable counterparts due to a longer retention of foreign materials in the human body. Here, we fabricated a fully degradable ventricular septum defect (VSD) occluder consisting of polydioxanone (PDO) fiber and poly-L-lactic acid (PLLA) membrane featuring an auto-locking function. The degradable occluder showed an excellent shape recovery effect after transcatheter delivery and anchored securely to a heart defect as evidenced by in vitro and in vivo experiments. The degradable occluder could warrant robust fixation ability during the first 3-months of implantation within which tissue reconstruction was accomplished and be completely absorbed within 12 months. Benefitting from these merits, the degradable occluder displayed desired occlusion and no complications after being implanted in the VSD sites of canines during a 24-months follow-up. Compared with traditional non-degradable occluders, our degradable occluder could provide a potentially superior approach for rapidly repairing the congenital VSD without interfering with the normal development and physiological function of the heart.

A Finite Element Investigation on Material and Design Parameters of Ventricular Septal Defect Occluder Devices.

Background and Objective: Ventricular septal defects (VSDs) are the most common form of congenital heart defects. The incidence of VSD accounts for 40% of all congenital heart defects (CHDs). With the development of interventional therapy technology, transcatheter VSD closure was introduced as an alternative to open heart surgery. Clinical trials of VSD occluders have yielded promising results, and with the development of new material technologies, biodegradable materials have been introduced into the application of occluders. At present, the research on the mechanical properties of occluders is focused on experimental and clinical trials, and numerical simulation is still a considerable challenge due to the braided nature of the VSD occluder. Finite element analysis (FEA) has proven to be a valid and efficient method to virtually investigate and optimize the mechanical behavior of minimally invasive devices. The objective of this study is to explore the axial resistive performance through experimental and computational testing, and to present the systematic evaluation of the effect of various material and braid parameters by FEA. Methods: In this study, an experimental test was used to investigate the axial resistive force (ARF) of VSD Nitinol occluders under axial displacement loading (ADL), then the corresponding numerical simulation was developed and compared with the experimental results to verify the effectiveness. Based on the above validation, numerical simulations of VSD occluders with different materials (polydioxanone (PDO) and Nitinol with different austenite moduli) and braid parameters (wire density, wire diameter, and angle between left and right discs) provided a clear presentation of mechanical behaviors that included the maximal axial resistive force (MARF), maximal axial displacement (MAD) and initial axial stiffness (IAS), the stress distribution and the maximum principal strain distribution of the device under ADL. Results: The results showed that: (1) In the experimental testing, the axial resistive force (ARF) of the tested occluder, caused by axial displacement loading (ADL), was recorded and it increased linearly from 0 to 4.91 N before reducing. Subsequent computational testing showed that a similar performance in the ARF was experienced, albeit that the peak value of ARF was smaller. (2) The investigated design parameters of wire density, wire diameter and the angle between the left and right discs demonstrated an effective improvement (7.59%, 9.48%, 1.28%, respectively, for MARF, and 1.28%, 1.80%, 3.07%, respectively, for IAS) for the mechanical performance for Nitinol occluders. (3) The most influencing factor was the material; the performance rose by 30% as the Nitinol austenite modulus (EA) increased by 10,000 MPa. The performance of Nitinol was better than that of PDO for certain wire diameters, and the performance improved more obviously (1.80% for Nitinol and 0.64% for PDO in IAS, 9.48% for Nitinol and 2.00% for PDO in MARF) with the increase in wire diameter. (4) For all of the models, the maximum stresses under ADL were distributed at the edge of the disc on the loaded side of the occluders. Conclusions: The experimental testing presented in the study showed that the mechanical performance of the Nitinol occluder and the MARF prove that it has sufficient ability to resist falling out from its intended placement. This study also represents the first experimentally validated computational model of braided occluders, and provides a perception of the influence of geometrical and material parameters in these systems. The results could further provide meaningful suggestions for the design of biodegradable VSD closure devices and to realize a series of applications for biodegradable materials in VSD.