Interventional approach to congenital heart disease

Additive manufacturing of vascular stents

With the advancement of additive manufacturing (AM), customized vascular stents can now be fabricated to fit the curvatures and sizes of a narrowed or blocked blood vessel, thereby reducing the possibility of thrombosis and restenosis. More importantly, AM enables the design and fabrication of complex and functional stent unit cells that would otherwise be impossible to realize with conventional manufacturing techniques. Additionally, AM makes fast design iterations possible while also shortening the development time of vascular stents. This has led to the emergence of a new treatment paradigm in which custom and on-demand-fabricated stents will be used for just-in-time treatments. This review is focused on the recent advances in AM vascular stents aimed at meeting the mechanical and biological requirements. First, the biomaterials suitable for AM vascular stents are listed and briefly described. Second, we review the AM technologies that have been so far used to fabricate vascular stents as well as the performances they have achieved. Subsequently, the design criteria for the clinical application of AM vascular stents are discussed considering the currently encountered limitations in materials and AM techniques. Finally, the remaining challenges are highlighted and some future research directions are proposed to realize clinically-viable AM vascular stents. STATEMENT OF SIGNIFICANCE: Vascular stents have been widely used for the treatment of vascular disease. The recent progress in additive manufacturing (AM) has provided unprecedented opportunities for revolutionizing traditional vascular stents. In this manuscript, we review the applications of AM to the design and fabrication of vascular stents. This is an interdisciplinary subject area that has not been previously covered in the published review articles. Our objective is to not only present the state-of-the-art of AM biomaterials and technologies but to also critically assess the limitations and challenges that need to be overcome to speed up the clinical adoption of AM vascular stents with both anatomical superiority and mechanical and biological functionalities that exceed those of the currently available mass-produced devices.

Safety and efficacy of larger ASD devices in small children of less than 2 years

We herein report our single center experience of safety and efficacy of device closure of large sized ostium secundum atrial septal defects (OS ASD) in small children with less than 2 years of age performed over the period of 10 years from 2009 to 2019.148 symptomatic children with ASD size of more than 8 mm were included in our study. We obtained a high rate of successful deployment (98 %) with no major complications.

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.

Amplatzer vascular plugs in congenital cardiovascular malformations

BACKGROUND

Amplatzer vascular plugs (AVPs) are devices ideally suited to close medium-to-large vascular communications. There is limited published literature regarding the utility of AVPs in congenital cardiovascular malformations (CCVMs).

AIMS

To describe the use of AVPs in different CCVMs and to evaluate their safety and efficacy.

MATERIALS AND METHODS

All patients who required an AVP for the closure of CCVM were included in this retrospective review of our catheterization laboratory data. The efficacy and safety of AVPs are reported.

RESULTS

A total of 39 AVPs were implanted in 31 patients. Thirteen (33%) were AVP type I and 23 (59%) were AVP type II. AVP type III were implanted in two patients and type IV in one patient. The major indications for their use included closure of pulmonary arteriovenous malformation (AVM) (n = 7), aortopulmonary collaterals (n = 7), closure of a patent Blalock-Taussig shunt (n = 5), systemic AVM (n = 5), coronary AVM (n = 4), patent ductus arteriosus (PDA) (n = 3), pulmonary artery aneurysms (n = 3), and venovenous collaterals (n = 2). Deployment of the AVP was done predominantly via the 5 - 7F Judkin's right coronary guide catheter. Overall 92% of the AVPs could be successfully deployed and resulted in occlusion of the target vessel in all cases, within 10 minutes. No procedure-related or access site complication occurred.

CONCLUSIONS

AVPs are versatile, easy to use, and effective devices to occlude the vascular communications in a variety of settings. AVP II is especially useful in the closure of tubular structures with a high flow.

Role of stents in congenital heart disease

For more than 10 years, balloon-expandable intravascular stents have become an integral part of treatment for obstructive vascular lesions in children and adults with congenital heart disease. The initial problems with stents, such as sharp edges, rigid frame and unacceptable shortening when over-expanded have been overcome to a large extent with the newer designs. The problems related to delivery of stents, such as stent migration, balloon rupture, flaring of the edges of the stent, rupture of vessels and milking of the stent off the balloon, have also been overcome by newer designs of balloons. The failure of growth of balloon-expandable stents with the growth of the child is managed by redilation with or without additional stenting and newer growth stents. Self-expanding stents are not appropriate for use in growing children due to the limitation of their maximum diameters. The development of biodegradable stents may overcome these disadvantages in the future. Various new developments have recently occurred. Covered stents are ideal for treating acute vessel rupture and in isolating vascular aneurysms. Drug-eluting stents may prevent restenosis, but have not been used in children. Valved stents are a recent innovation for the treatment of regurgitant pulmonary valves.

A new coated nitinol occluder for transcatheter closure of ventricular septal defects in a canine model

Aims. This study evaluated feasibility and safety of implanting the polyester-coated nitinol ventricular septal defect occluder (pcVSDO) in the canine model. Methods and Results. VSD models were successfully established by transseptal ventricular septal puncture via the right jugular vein in 15 out of 18 canines. Two types of VSDOs were implanted, either with pcVSDOs (n = 8) as the new type occluder group or with the commercial ventricular septal defect occluders (VSDOs, n = 7, Shanghai Sharp Memory Alloy Co. Ltd.) as the control group. Sheath size was 10 French (10 Fr) in two groups. Then the general state of the canines was observed after implantation. ECG and TTE were performed, respectively, at 7, 30, 90 days of follow-up. The canines were sacrificed at these time points for pathological and scanning electron microscopy examination. The devices were successfully implanted in all 15 canines and were retrievable and repositionable. There was no thrombus formation on the device or occurrence of complete heart block. The pcVSDO surface implanted at day 7 was already covered with neotissue by gross examination, and it completed endothelialization at day 30, while the commercial VSDO was covered with the neotissue in 30th day and the complete endothelialization in 90th day. Conclusion. The study shows that pcVSDO is feasible and safe to close canine VSD model and has good biocompatibility and shorter time of endothelialization.

Transcatheter closure of secundum atrial septal defect in patients over 60 years old

BACKGROUND AND OBJECTIVES

Atrial septal defect (ASD) is the one of most common congenital heart diseases detected in adults. Along with remarkable development of device technology, the first treatment strategy of secundum ASD has been transcatheter closure in feasible cases. However, there are only a few publications regarding the results of transcatheter closure of ASD in elderly patients, especially those over 60 years of age. We report our results of transcatheter closure of ASD in patients over 60 years old.

SUBJECTS AND METHODS

Between May 2006 and December 2011, 31 patients over 60 years old (25 female and 6 male; mean 66.7±5.25 years old, range 61-78 years old) were referred to our center.

RESULTS

A total of 23 patients underwent therapeutic catheterization to close secundum ASD, and the closure was successful in 22 patients (95.7%). All patients who underwent the procedure survived except for one patient who expired because of left ventricular dysfunction. A small residual shunt was observed in two (9%) of 21 patients before discharge but disappeared at follow-up. All patients eventually had complete closure. There were five patients who had coronary problems. One patient underwent percutaneous coronary intervention using a stent at the same time as transcatheter closure of ASD. Atrial arrhythmias were detected in 6 of 23 patients (26.1%) before the procedure. One patient was successfully treated by radiofrequency ablation before the procedure. No patients displayed new onset arrhythmia during the follow-up period. Follow-up echocardiographic evaluation showed a significantly improved right ventricular geometry.

CONCLUSION

We conclude that transcatheter closure of ASD is a safe and an effective treatment method for patients over 60 years old if the procedure is performed under a thorough evaluation of comorbidities and risk factors.

Transcatheter closure of atrial septal defect: does age matter?

Atrial septal defect (ASD) is the most common type of common congenital heart disease (CHD) in adults. During the last decade, there has been a remarkable change in the treatment strategy of ASD, shifting the therapeutic gold standard from surgery to transcatheter closure, along with refinements and the evolution of device technology. Reports on the outcome of transcatheter ASD closure have shown an excellent efficacy as well as a low complication rate. However, the procedural details and/or outcomes of this procedure may be influenced by several factors including morphologic characteristics of the defect, co-morbid diseases, as well as individual factors including age and weight of the patient. Because the risk-benefit relationship in both the very young and the elderly subsets of the patients has not been clearly defined yet, closure of an ASD with device may be potentially subtracted from the treatment option in these patient groups. In this article, we will review the basis for device closure in small children and elderly patients with ASD and provide an overview of the frequently encountered problems.

The influence of Ni(II) on surface antigen expression in murine macrophages

Biomedical alloys may release nickel ions during corrosion phenomena and, in addition to their interaction with oral tissues, these ions may also influence characteristic properties of the immune system cells. The aim of this study was to evaluate the effect of nickel chloride on the expression of functionally distinct surface antigens in murine RAW macrophages. The expression of the surface antigens CD14, CD40, MHC class I, MHC class II, CD80, CD86, CD54 was analyzed by flow cytometry. The bacterial endotoxin lipopolysaccharide (LPS) was used as a positive control to induce antigen expression. Cells were stimulated with NiCl(2) (0.1 and 0.5mm) in the presence and absence of LPS (0.1 or 25 microg/ml). After exposure periods of 6, 24 and 48 h, LPS caused a time- and dose-dependent increase in the expression of all surface antigens. CD14 expression was up-regulated by 0.1 microg/ml LPS by about 10-fold after 24h and 100-fold after 48 h. After 48 h, NiCl(2) alone up-regulated the expression of all surface antigens between 2- and 4-fold, while in cells stimulated by LPS, 0.1mm NiCl(2) was effective only on CD14, CD40 and MHC class I. Moreover, 0.5mm NiCl(2) even inhibited the LPS-induced expression of all surface antigens, except for CD54, which was still significantly up-regulated. These results show that nickel chloride is able to induce an up-regulation of surface antigen expression, but a high concentration may impair essential functions of macrophages stimulated by LPS.

Covered stents in the management of coarctation of the aorta in the adult: initial results and 1-year angiographic and hemodynamic follow-up

BACKGROUND

The purpose of this study was to determine the safety and efficacy of the Cheatham Platinum covered stent in adults with coarctation of the aorta.

METHODS

Adults with native coarctations (n=14); previous coarctation surgery (n=4), stenting (n=1) or both surgery and endovascular therapy (n=3) underwent percutaneous intervention with a covered stent. Indications for stenting in those with previous intervention were recurrent coarctation (n=4), aneurysm formation at the site of previous intervention (n=2) or both recurrent coarctation and aneurysm formation (n=2).

RESULTS

Twenty-three covered stents were placed in 22 patients (mean age 39+/-14 years, n=11 males). Successful device deployment was achieved in all patients, although one patient required a second covered stent for aortic wall rupture. Peak systolic gradient across the coarctation site decreased from 29+/-17 to 3+/-5 mm Hg (p<0.001) immediately following implant and this was maintained (6+/-9 mm Hg, p=0.001) at invasive assessment, 12 months after the initial procedure. Right arm systolic blood pressure significantly declined (p=0.02), as did the number of antihypertensive medications per patient (p=0.03). At angiographic follow-up, post-stenotic dilatation of the aorta decreased from 32+/-8 mm to 30+/-8 mm (p=0.001), however, no stent recoil was observed.

CONCLUSIONS

Covered stents are safe, durable and efficacious in the management of coarctation of the aorta. Angiography and hemodynamic assessment is an effective method of screening for recurrent coarctation, and arch and vascular complications after stenting in adults.

Pediatric Nuclear Cardiology

Echocardiography, magnetic resonance imaging and, more recently, multidetector computed tomography, have led to major advances in noninvasive image assessment of anatomy in pediatric cardiology. The radionuclide methods often lack sufficient resolution to precisely characterize complex morphology in congenital heart lesions. However, these methods provide an accurate and reproduceable quantitative assessment of the physiological consequences of structural heart disease. These unique capabilities will continue to assure ongoing clinical relevance of radionuclide methodology, as is the case in the assessment of heart disease in adult cardiology.

Percutaneous closure of a para-prosthetic aorto-right ventricular fistula

A 60-year-old woman with increasing dyspnea was found to have a para-prosthetic aorto-right ventricular fistula during post-operative evaluation. Due to her multiple sternotomies, she was considered to be high risk for open surgical repair and referred for percutaneous intervention. A 6/4 mm Amplatzer occluder device (AGA Medical, Golden Valley, MN) was successfully delivered across the fistula with excellent immediate angiographic results.

Diagnostic reference levels and effective dose in paediatric cardiac catheterization

European states within the EEC are required to establish and use diagnostic reference levels (DRLs) in X-ray examinations. However, up to now there have been no DRLs for cardiac catheterization in children, nor as a rule is the effective dose estimated. We have evaluated the dose-area products (DAPs) for three different types of angiocardiography systems over a time span of 8 years. For each system DAP increased in proportion to the body weight (BW) over two orders of magnitude. The proportionality constant decreased over the years. To reduce the broad distribution of DAP the doses for cine acquisition (DAPA) and fluoroscopy (DAPF) were indexed with respect to the total numbers of acquired images (AN) and the total times of fluoroscopy (FT). DAPA/AN is directly proportional to BW with a high correlation (r = 0.896, n = 1346). Likewise, DAPF/FT is proportional to BW from 0.1 kg to 100 kg (r = 0.84, n = 2138). Therefore, by normalizing DAP to BW the growth dependent variation of DAP can be eliminated. There are numerous short examinations with very small total DAPs, which were separated from the group of diagnostic examinations. The mean DAP/BW of this group is 0.41 Gycm2 kg(-1) (90th percentile: 0.81 Gycm2 kg(-1), n = 1106). For interventional procedures in congenital heart diseases DAP/BW is significantly higher (p<0.001) (mean: 0.56 Gycm2 kg(-1), 90th percentile: 1.16 Gycm2 kg(-1), n = 883). There are significant differences between different types of interventional procedures, the mean values being between 0.35 Gycm2 kg(-1) (occlusion of patent ductus botalli, n = 165) and 1.30 Gycm2 kg(-1) (occlusion of ventricular septal defect, n = 32). For patients who are catheterized several times over the years, the cumulative effective dose (E) may reach high values, being especially high for patients with hypoplastic left heart syndrome (typically 11 mSv). E is derived from DAP/BW by use of a constant DAP/BW to E conversion factor, independent of the age of the patient. DAP/BW is appropriate to describe paediatric DRLs and is recommended instead of using mean DAP values for age groups.

Early Cardiac Perforation After Atrial Septal Defect Closure With the Amplatzer Septal Occluder

We report a case of aortic perforation after transcatheter closure of an atrial septal defect by an Amplatzer septal occluder. During emergency surgery, perforations of the dome of the right atrium and the noncoronary sinus of Valsalva of the aorta were repaired. Atrial septal defect was primarily closed. A short anterosuperior rim should be considered a risk factor for aortic perforation in transcatheter atrial septal defect closure.

Endocarditis after closure of ventricular septal defect by transcatheter device

Advances in interventional cardiology have enabled the treatment of severe congenital heart defects without the need for surgery. The percutaneous closure of atrial septal defects and, more recently, ventricular septal defects is considered a safe procedure with fewer complications and less morbidity compared with surgery. We report on a 2-year-old child who developed endocarditis after ventricular septal defect closure with an Amplatzer device. The patient recovered after intravenous antibiotics and anticoagulation. To the best of our knowledge, this is the first report of endocarditis associated with ventricular septal defect closure device insertion.

Successful percutaneous closure of paraprosthetic aorto-right ventricular leak using the Amplatzer duct occluder

A 55-year-old male with persisting aorto-right ventricular paraprosthetic leak after mitroaortic valve replacement was hospitalized for recurrent heart failure. Depressed left ventricular ejection fraction and severe pulmonary hypertension with increased right and left ventricular filling pressures were associated with significant left to right shunting through the leak. Elective closure of the leak was obtained with a 6-4 mm Amplatzer duct occluder. No complications were observed, and the patient experienced complete resolution of heart failure symptoms, with NYHA class I heart failure 12 months after discharge.

Transcatheter closure of an atrial septal defect in a dog

Atrial septal defect, while rare in dogs, can result in severe clinical signs. Surgical correction of atrial septal defect requires open-heart surgery. Transcatheter closure techniques provide minimally invasive surgical alternatives.

Long-term outcome of transcatheter secundum-type atrial septal defect closure using Amplatzer septal occluders

OBJECTIVES

The aim of this study was to assess long-term results of percutaneous closure of secundum-type atrial septal defect (ASD II) using Amplatzer septal occluders (ASO).

BACKGROUND

Only immediate-, short-, and intermediate-term results of ASO implantation are known so far.

METHODS

Between September 1995 and January 2000, 151 patients underwent a successful percutaneous closure of ASD II in our institution. All were included in the present study and were followed up until September 2004.

RESULTS

This group of patients was followed up from 56 to 108 months (median 78 months). The mean stretched defect diameter was 15.9 +/- 4.8 mm. There were no deaths or significant complications during the study. At three years of follow-up, all defects were completely closed and remained closed thereafter.

CONCLUSIONS

Since the first human implantations in September 1995, the Amplatzer septal occluder proved as a safe and effective device for percutaneous closure of ASD II.

Real-time 3D echocardiography-guided transcatheter device closure of atrial septal defects

We report our initial experience using real-time (live) three-dimensional (3D) transthoracic echocardiographic imaging under conscious sedation as a guide for transcatheter device closure of atrial septal defects. We believe this may be a feasible, safe, and effective alternative to the standard practice of transesophageal echocardiography, which requires general anesthesia and endotacheal intubation. Three-dimensional echocardiography may better define atrial septal anatomy and adjacent structures in planning for and performing percutaneous device closure of selected atrial septal defects.