Porcine Intestinal Submucosa (CorMatrix) for Semilunar Valve Repair in Children: A Word of Caution After Midterm Results

One-Year Outcome of an Ongoing Pre-Clinical Growing Animal Model for a Tissue-Engineered Valved Pulmonary Conduit

Objectives: A self-constructed valved pulmonary conduit made out of a de-cellularized porcine small intestinal submucosal extracellular matrix biological scaffold was tested in a chronic growing lamb model. Methods: The conduit was implanted in pulmonary valve position in 19 lambs. We monitored clinical, laboratory, and echocardiographic findings until 12 months after surgery. In two animals, euthanasia was planned at nine and twelve months. Pre-mortem chest computed tomography and post-mortem pathologic work up were performed. Data are presented as frequency and percentage, median and range, or mean and standard deviation. Results: Twelve (63.2%) animals survived the perioperative period. Three unexpected deaths occurred during the follow-up period: one due to aspiration pneumonia at 23 days after surgery, and two due to early and late infective endocarditis of the conduit at 18 and 256 days. In the two animals with planned scarification, the pre-mortem CT scan revealed mild or no calcification within the conduit or valve leaflets. In the echocardiographic examination at 12 months, peak and mean systolic pressure gradients across the conduit valve were 6.5 (3-21) mmHg and 3 (2-12) mmHg, while valve regurgitation was none (n = 2), trivial (n = 5), moderate (n = 1), or severe (n = 1). No clinical or laboratory signs of hemolysis were seen. After 12 months of follow-up, the animals' body weights had increased from 33 (27-38) kg to 53 (38-66) kg (p = 0.010). Conclusions: Implantation of a valved pulmonary conduit in our growing lamb model was feasible. Infective endocarditis of the implanted valved conduit remained a significant complication.

Evaluation of pliable bioresorbable, elastomeric aortic valve prostheses in sheep during 12 months post implantation

Pliable microfibrous, bioresorbable elastomeric heart valve prostheses are investigated in search of sustainable heart valve replacement. These cell-free implants recruit cells and trigger tissue formation on the valves in situ. Our aim is to investigate the behaviour of these heart valve prostheses when exposed to the high-pressure circulation. We conducted a 12-month follow-up study in sheep to evaluate the in vivo functionality and neo-tissue formation of these valves in the aortic position. All valves remained free from endocarditis, thrombotic complications and macroscopic calcifications. Cell colonisation in the leaflets was mainly restricted to the hinge area, while resorption of synthetic fibers was limited. Most valves were pliable and structurally intact (10/15), however, other valves (5/15) showed cusp thickening, retraction or holes in the leaflets. Further research is needed to assess whether in-situ heart valve tissue engineering in the aortic position is possible or whether non-resorbable synthetic pliable prostheses are preferred.

Multiscale analysis of human tissue engineered matrices for next generation heart valve applications

Human tissue-engineered matrices (hTEMs) have been proposed as a promising approach for in situ tissue engineered heart valves (TEHVs). However, there is still a limited understanding on how ECM composition in hTEMs develops over tissue culture time. Therefore, we performed a longitudinal hTEM assessment by 1) multiscale evaluation of hTEM composition during culture time (2, 4, 6-weeks), using (immuno)histology, biochemical assays, and mass spectrometry (LC-MS/MS); 2) analysis of protein pathways involved in ECM development using gene set enrichment analysis (GSEA); and 3) assessment of hTEM mechanical characterization using uniaxial tensile testing. Finally, as a proof-of-concept, TEHVs manufactured using 6-weeks hTEM samples were tested in a pulse duplicator. LC-MS/MS confirmed the tissue culture time-dependent increase in ECM proteins observed in histology and biochemical assays, revealing the most abundant collagens (COL6, COL12), proteoglycans (HSPG2, VCAN), and glycoproteins (FN, TNC). GSEA identified the most represented protein pathways in the hTEM at 2-weeks (mRNA metabolic processes), 4-weeks (ECM production), and 6-weeks (ECM organization and maturation). Uniaxial mechanical testing showed increased stiffness and stress at failure, and reduction in strain over tissue culture time. hTEM-based TEHVs demonstrated promising in vitro performance at both pulmonary and aortic pressure conditions, with symmetric leaflet coaptation and no stenosis. In conclusion, ECM protein abundance and maturation increased over tissue culture time, with consequent improvement of hTEM mechanical characteristics. These findings suggest that longer tissue culture impacts tissue organization, leading to an hTEM that may be suitable for high-pressure applications. STATEMENT OF SIGNIFICANCE: It is believed that the composition of the extracellular matrix (ECM) in the human tissue engineered matrices (hTEM) may favor tissue engineered heart valve (TEHV) remodeling upon implantation. However, the exact protein composition of the hTEM, and how this impacts tissue mechanical properties, remains unclear. Hence, we developed a reproducible rotation-based tissue culture method to produce hTEM samples. We performed a longitudinal assessment using different analytical techniques and mass spectrometry. Our data provided an in-depth characterization of the hTEM proteome with focus on ECM components, their development, and how they may impact the mechanical properties. Based on these results, we manufactured functional hTEM-based TEHVs at aortic-like condition in vitro. These outcomes pose an important step in translating hTEM-based TEHVs into clinics and in predicting their remodeling potential upon implantation.

Extracellular matrix-derived scaffolds in constructing artificial ovaries for ovarian failure: a systematic methodological review

STUDY QUESTION

What is the current state-of-the-art methodology assessing decellularized extracellular matrix (dECM)-based artificial ovaries for treating ovarian failure?

SUMMARY ANSWER

Preclinical studies have demonstrated that decellularized scaffolds support the growth of ovarian somatic cells and follicles both in vitro and in vivo.

WHAT IS KNOWN ALREADY

Artificial ovaries are a promising approach for rescuing ovarian function. Decellularization has been applied in bioengineering female reproductive tract tissues. However, decellularization targeting the ovary lacks a comprehensive and in-depth understanding.

STUDY DESIGN SIZE DURATION

PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials were searched from inception until 20 October 2022 to systematically review all studies in which artificial ovaries were constructed using decellularized extracellular matrix scaffolds. The review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol.

PARTICIPANTS/MATERIALS SETTING METHODS

Two authors selected studies independently based on the eligibility criteria. Studies were included if decellularized scaffolds, regardless of their species origin, were seeded with ovarian cells or follicles. Review articles and meeting papers were removed from the search results, as were articles without decellularized scaffolds or recellularization or decellularization protocols, or control groups or ovarian cells.

MAIN RESULTS AND THE ROLE OF CHANCE

The search returned a total of 754 publications, and 12 papers were eligible for final analysis. The papers were published between 2015 and 2022 and were most frequently reported as coming from Iran. Detailed information on the decellularization procedure, evaluation method, and preclinical study design was extracted. In particular, we concentrated on the type and duration of detergent reagent, DNA and extracellular matrix detection methods, and the main findings on ovarian function. Decellularized tissues derived from humans and experimental animals were reported. Scaffolds loaded with ovarian cells have produced estrogen and progesterone, though with high variability, and have supported the growth of various follicles. Serious complications have not been reported.

LIMITATIONS REASONS FOR CAUTION

A meta-analysis could not be performed. Therefore, only data pooling was conducted. Additionally, the quality of some studies was limited mainly due to incomplete description of methods, which impeded specific data extraction and quality analysis. Several studies that used dECM scaffolds were performed or authored by the same research group with a few modifications, which might have biased our evaluation.

WIDER IMPLICATIONS OF THE FINDINGS

Overall, the decellularization-based artificial ovary is a promising but experimental choice for substituting insufficient ovaries. A generic and comparable standard should be established for the decellularization protocols, quality implementation, and cytotoxicity controls. Currently, decellularized materials are far from being clinically applicable to artificial ovaries.

STUDY FUNDING/COMPETING INTERESTS

This study was funded by the National Natural Science Foundation of China (Nos. 82001498 and 81701438). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

This systematic review is registered with the International Prospective Register of Systematic Reviews (PROSPERO, ID CRD42022338449).

Outcomes of Repair of Congenital Aortic Valve Lesions Using Autologous Pericardium vs Porcine Intestinal Submucosa

BACKGROUND

Outcomes following congenital aortic valve (AoV) repair are plagued by progressive dysfunction of currently available leaflet substitute materials.

OBJECTIVES

We compared the long-term outcomes of congenital AoV repair using porcine intestinal submucosa vs autologous pericardium (AP).

METHODS

This was a single-center retrospective review of all patients who underwent congenital AoV repair with either porcine intestinal submucosa or AP from October 2009 to March 2013. The primary outcome was postdischarge (late) unplanned AoV reintervention. Secondary outcomes included number of late AoV reinterventions and a composite of at least moderate aortic regurgitation or stenosis at latest follow-up or before the first reintervention. Associations between leaflet repair material and outcomes were assessed using multivariable regression models, adjusting for prespecified patient-related and operative variables.

RESULTS

Of 26 porcine intestinal submucosa and 49 AP patients who met entry criteria, the median age was 11.0 years (IQR: 4.7-16.6 years). At a median follow-up of 8.5 years (IQR: 4.4-9.6 years), 17 (65.4%) porcine intestinal submucosa and 22 (44.9%) AP patients underwent at least 1 AoV reintervention. On multivariable analysis, porcine intestinal submucosa use was significantly associated with unplanned AoV reintervention (HR: 4.6; 95% CI: 2.2-9.8; P < 0.001), number of postdischarge AoV reinterventions (incidence rate ratio: 1.7; 95% CI: 1.0-2.9; P = 0.037), and at least moderate aortic regurgitation or stenosis at latest follow-up or before the first reintervention (OR: 5.0; 95% CI: 1.2-21.0; P = 0.027).

CONCLUSIONS

Aortic valvuloplasty with porcine intestinal submucosa is associated with earlier time to reintervention compared with autologous pericardium. The search for the ideal AoV leaflet repair material continues.

Macrophage-extracellular matrix interactions: Perspectives for tissue engineered heart valve remodeling

In situ heart valve tissue engineering approaches have been proposed as promising strategies to overcome the limitations of current heart valve replacements. Tissue engineered heart valves (TEHVs) generated from in vitro grown tissue engineered matrices (TEMs) aim at mimicking the microenvironmental cues from the extracellular matrix (ECM) to favor integration and remodeling of the implant. A key role of the ECM is to provide mechanical support to and attract host cells into the construct. Additionally, each ECM component plays a critical role in regulating cell adhesion, growth, migration, and differentiation potential. Importantly, the immune response to the implanted TEHV is also modulated biophysically via macrophage-ECM protein interactions. Therefore, the aim of this review is to summarize what is currently known about the interactions and signaling networks occurring between ECM proteins and macrophages, and how these interactions may impact the long-term in situ remodeling outcomes of TEMs. First, we provide an overview of in situ tissue engineering approaches and their clinical relevance, followed by a discussion on the fundamentals of the remodeling cascades. We then focus on the role of circulation-derived and resident tissue macrophages, with particular emphasis on the ramifications that ECM proteins and peptides may have in regulating the host immune response. Finally, the relevance of these findings for heart valve tissue engineering applications is discussed.

Bioengineering Human Tissues and the Future of Vascular Replacement

Cardiovascular defects, injuries, and degenerative diseases often require surgical intervention and the use of implantable replacement material and conduits. Traditional vascular grafts made of synthetic polymers, animal and cadaveric tissues, or autologous vasculature have been utilized for almost a century with well-characterized outcomes, leaving areas of unmet need for the patients in terms of durability and long-term patency, susceptibility to infection, immunogenicity associated with the risk of rejection, and inflammation and mechanical failure. Research to address these limitations is exploring avenues as diverse as gene therapy, cell therapy, cell reprogramming, and bioengineering of human tissue and replacement organs. Tissue-engineered vascular conduits, either with viable autologous cells or decellularized, are the forefront of technology in cardiovascular reconstruction and offer many benefits over traditional graft materials, particularly in the potential for the implanted material to be adopted and remodeled into host tissue and thus offer safer, more durable performance. This review discusses the key advances and future directions in the field of surgical vascular repair, replacement, and reconstruction, with a focus on the challenges and expected benefits of bioengineering human tissues and blood vessels.

Can Heart Valve Decellularization Be Standardized? A Review of the Parameters Used for the Quality Control of Decellularization Processes

When a tissue or an organ is considered, the attention inevitably falls on the complex and delicate mechanisms regulating the correct interaction of billions of cells that populate it. However, the most critical component for the functionality of specific tissue or organ is not the cell, but the cell-secreted three-dimensional structure known as the extracellular matrix (ECM). Without the presence of an adequate ECM, there would be no optimal support and stimuli for the cellular component to replicate, communicate and interact properly, thus compromising cell dynamics and behaviour and contributing to the loss of tissue-specific cellular phenotype and functions. The limitations of the current bioprosthetic implantable medical devices have led researchers to explore tissue engineering constructs, predominantly using animal tissues as a potentially unlimited source of materials. The high homology of the protein sequences that compose the mammalian ECM, can be exploited to convert a soft animal tissue into a human autologous functional and long-lasting prosthesis ensuring the viability of the cells and maintaining the proper biomechanical function. Decellularization has been shown to be a highly promising technique to generate tissue-specific ECM-derived products for multiple applications, although it might comprise very complex processes that involve the simultaneous use of chemical, biochemical, physical and enzymatic protocols. Several different approaches have been reported in the literature for the treatment of bone, cartilage, adipose, dermal, neural and cardiovascular tissues, as well as skeletal muscle, tendons and gastrointestinal tract matrices. However, most of these reports refer to experimental data. This paper reviews the most common and latest decellularization approaches that have been adopted in cardiovascular tissue engineering. The efficacy of cells removal was specifically reviewed and discussed, together with the parameters that could be used as quality control markers for the evaluation of the effectiveness of decellularization and tissue biocompatibility. The purpose was to provide a panel of parameters that can be shared and taken into consideration by the scientific community to achieve more efficient, comparable, and reliable experimental research results and a faster technology transfer to the market.

Over 400 Uses of An Intestinal Submucosal Extracellular Matrix Patch in a Congenital Heart Program

BACKGROUND

Repair of complex congenital heart disease frequently requires usage of a patch as an anatomical substitute. The study's aim is to evaluate the use, effectiveness and safety of utilizing small intestine submucosa extracellular matrix (SIS-ECM) patches in a congenital cardiac surgery program.

METHODS

This is a single-center, retrospective, cohort study of surgeries utilizing SIS-ECM between 2012-2019. The SIS-ECM data was categorized by usage and type (4-ply and 2-ply). All re-interventions/complications were reviewed by an independent surgeon, a practicing congenital heart surgeon and a pediatric cardiologist.

RESULTS

408 SIS-ECM patches were used in 309 patients (M/F=188/121; median age 8.5months). The usage consisted of 314 (77%) arterioplasties, 22 (5.4%) venoplasties, 63 (15.4%) intracardiac repairs, and 9 (2.2%) valve repairs. The most common usage was pulmonary artery repair (n=181; 44.4%). Median follow-up time was 3.9 years (range: 3days-7.4years). Ten (2.5%) patches required surgical (2 in first 30-days and 5 in 1^st year) and 27 (6.6%) required percutaneous re-interventions (2 in first 30-days and 22 in 1^st year). Between 4-ply (n=376) and 2-ply (n=32) SIS-ECM, rate of surgical (2.1% (n=8) vs 6.3% (n=2); p=0.18) or percutaneous re-interventions (6.4% (n=24) vs 9.4% (n=3); p=0.46) was not different. There were no deaths related to the SIS-ECM patch or reports of calcification.

CONCLUSIONS

SIS-ECM is a viable patch option that can be used in various cardiac and vascular reconstructive surgeries with low risk of failure and calcification. Long-term, positive outcomes may be maximized by consistent techniques and understanding appropriate applications of the patch.

Decellularized xenografts in regenerative medicine: From processing to clinical application

Decellularized xenografts are an inherent component of regenerative medicine. Their preserved structure, mechanical integrity and biofunctional composition have well established them in reparative medicine for a diverse range of clinical indications. Nonetheless, their performance is highly influenced by their source (ie species, age, tissue) and processing (ie decellularization, crosslinking, sterilization and preservation), which govern their final characteristics and determine their success or failure for a specific clinical target. In this review, we provide an overview of the different sources and processing methods used in decellularized xenografts fabrication and discuss their effect on the clinical performance of commercially available decellularized xenografts.

Pathological Changes of Adult Mitral Valves after Failed CorMatrix ECM Repair

BACKGROUND AND OBJECTIVES

CorMatrix acts as a tissue scaffold and is intended to promote the proliferation of small vessels and tissue remodeling to replicate normal tissue function.

METHODS

At Temple University Hospital, Philadelphia, PA, USA from 2013 to 2016, CorMatrix material was utilized during mitral valve anterior leaflet augmentation repair in 25 adult patients, and four patients required repeat interventions at 4-12 months (8.25 ± 4.35 months) after the initial repair. This study evaluated the pathological changes in four patients.

RESULTS

Histological examination of the CorMatrix showed matrix degradation in all cases. At 4 months after repair, mixed acute and chronic inflammatory cells that included eosinophils were visible within the matrix, which was more severe around the suture material. Later, the extent of inflammation abated and became more chronic with macrophage dominance. Some macrophages and multinucleated cells were visible deep in the matrix. The neovascularization was limited to the tissue-matrix boundary at early time points; the more mature vessels with dilated lumens extended deeper into the matrix as time increased, combined with some elongated fibroblast-like cells. In addition, marked acute and chronic inflammation with neutrophil and eosinophil infiltrate was identified in the surrounding native tissue at 4 months, especially around the suture material. Marked granulomatous inflammation was identified in all cases, with prominent multinucleated giant cells present at later time points (50%). Immunohistochemical staining for CD68 and CD163 showed prominent M2 macrophages in the CorMatrix and surrounding tissue.

CONCLUSIONS

Our results demonstrated time-dependent changes in failed CorMatrix repaired valves after mitral valve repair, with macrophages and neovascularization in the matrix 12 months after the initial repair.

Recurrent ventricular septal defect following closure CorMatrix: A case report

Ventricular septal ruptures are an uncommon complication following acute myocardial infarction. Operative repair, utilizing a patch for closure of the defect, is the primary treatment modality to achieve hemodynamic stability. The use of an extracellular matrix derived from small intestinal submucosa as a scaffold for tissue repair is becoming increasingly common. Here, we present the case of a 58-year-old female found to have a ventricular septal rupture and posterior left ventricular aneurysm following late presentation after a myocardial infarction that required operative repair with a CorMatrix patch. Upon readmission for dyspnea and poor exercise tolerance several months later, the patch was subsequently found to have near-completely reabsorbed. There is a paucity of long-term outcomes data following the use of CorMatrix for septal defects, with rare reports of such reabsorption. Further study is required to identify the incidence and implications of such findings.

Next-generation tissue-engineered heart valves with repair, remodelling and regeneration capacity

Valvular heart disease is a major cause of morbidity and mortality worldwide. Surgical valve repair or replacement has been the standard of care for patients with valvular heart disease for many decades, but transcatheter heart valve therapy has revolutionized the field in the past 15 years. However, despite the tremendous technical evolution of transcatheter heart valves, to date, the clinically available heart valve prostheses for surgical and transcatheter replacement have considerable limitations. The design of next-generation tissue-engineered heart valves (TEHVs) with repair, remodelling and regenerative capacity can address these limitations, and TEHVs could become a promising therapeutic alternative for patients with valvular disease. In this Review, we present a comprehensive overview of current clinically adopted heart valve replacement options, with a focus on transcatheter prostheses. We discuss the various concepts of heart valve tissue engineering underlying the design of next-generation TEHVs, focusing on off-the-shelf technologies. We also summarize the latest preclinical and clinical evidence for the use of these TEHVs and describe the current scientific, regulatory and clinical challenges associated with the safe and broad clinical translation of this technology.

Establishing a pre-clinical growing animal model to test a tissue engineered valved pulmonary conduit

Background

Many valvular pathologies of the heart may be only sufficiently treated by replacement of the valve if a reconstruction is not feasible. However, structural deterioration, thrombosis with thromboembolic events and infective endocarditis are commonly encountered complications over time and often demand a re-operation. In congenital heart disease the lack of small diameter valves with the potential to grow poses additional challenges and limits treatment options to homo- or xenograft implants.

Methods

In this study, a chronic sheep model (24 months follow-up), a self-constructed valved conduit was created out of a tissue engineered (TE) patch (CorMatrix® Cardiovascular, Inc, USA) and implanted in orthotopic right ventricular (RV)-pulmonary artery (PA) position. Thereafter, the sheep were regularly monitored by clinical, laboratory and echocardiographic examinations to evaluate cardiac function and the implanted RV-PA-conduit.

Discussion

Here, we summarize the study protocol and our experiences during the perioperative phase and the follow up period and explain how we constructed a valved conduit out of a commercially available TE patch.

Trial registration

License number: ZH 284/14.

Failure of decellularized porcine small intestinal submucosa as a heart valved conduit

OBJECTIVE

Decellularized extracellular matrix made from porcine small intestinal submucosa, commercially available as CorMatrix (CorMatrix Cardiovascular, Inc, Roswell, Ga) is used off-label to reconstruct heart valves. Recently, surgeons experienced failures and words of caution were raised. The aim of this study was to evaluate decellularized porcine small intestinal submucosa as right-sided heart valved conduit in a xenogeneic animal model.

METHODS

A pulmonary valve replacement was performed with custom-made valved conduits in 10 lambs and 10 sheep (1 month [3 lambs and 3 sheep], 3 months [3 lambs and 3 sheep], 6 months [4 lambs and 4 sheep]). Valve function was assessed after implantation and before the animal was put to death. Explanted conduits were inspected macroscopically and analyzed using immunohistochemistry and scanning electron microscopy. They also underwent mechanical testing and testing for biochemical composition.

RESULTS

All valved conduits were successfully implanted. Five sheep and 2 lambs died due to congestive heart failure within 2 months after surgery. In the animals that died, the valve leaflets were thickened with signs of inflammation (endocarditis in 4). Five sheep and 8 lambs (1 month: 6 out of 6 animals, 3 months: 4 out of 6 animals, 6 months: 3 out of 8 animals) survived planned follow-up. At the time they were put to death, 5 lambs had significant pulmonary stenosis and 1 sheep showed severe regurgitation. A well-functioning valve was seen in 4 sheep and 3 lambs for up to 3 months. These leaflets showed limited signs of remodeling.

CONCLUSIONS

Fifty percent of sheep and 20% of lambs died due to valve failure before the planned follow-up period was complete. A well-functioning valve was seen in 35% of animals, albeit with limited signs of tissue remodeling at ≤3 months after implantation. Further analysis is needed to understand the disturbing dichotomous outcome before clinical application can be advised.

Histological analysis of failed submucosa patches in congenital cardiac surgery

Objective

Porcine small intestinal submucosa extracellular matrix is a biological substitute used in cardiovascular surgery to correct congenital heart defects. Previous studies with this material have shown satisfactory results. In contrast, there are singular reports of patch-associated complications with CorMatrix small intestinal submucosa extracellular matrix. We report the histopathological findings of explanted extracellular matrix patches that were removed because of early failure in patients with congenital heart defects.

Methods

Explanted patch materials from 4 patients (aged 9 months to 41 years), who underwent reoperation due to early patch failure, were analyzed. Initial surgery comprised one aortic valve reconstruction, one pulmonary valve reconstruction, one atrioventricular septal defect repair, and one aortic arch enlargement. The interval between operations ranged from 69 to 553 days.

Results

Residual extracellular matrix patch material was evident at explantation in all cases and presented as a structured eosinophilic and anucleate specimen. In two cases, a local focus of scarring and pseudocartilaginous transformation with evidence of calcification was found. There was no evidence of absorption of patch material in any case, nor repopulation by organized tissue formation.

Conclusions

Histologic examination of explanted extracellular matrix patches showed no evidence of resorption or relevant repopulation with resident cells nor formation of functional tissue structures. In contrast, a mixed chronic inflammatory infiltration, early signs of calcification, and scarring as well as focal pseudocartilaginous transformation were found. Considering recent reports, close follow-up of patients with extracellular matrix patches is recommended to evaluate the performance of this novel material and detect potential problems.

Current spectrum, challenges and new developments in the surgical care of adults with congenital heart disease

Today, more than two thirds of patients with congenital heart disease (CHD) are adults. Cardiac surgery plays an essential role in restoring and maintaining cardiac function, aside from evolving medical treatment and catheter-based interventions. The aim of the present publication was to describe the spectrum of operations performed on adults with CHD (ACHD) by reviewing current literature. Currently, surgery for ACHD is predominantly valve surgery, since valvular pathologies are often either a part of the basic heart defect or develop as sequelae of corrective or palliative surgery. Surgical techniques for valve repair, established in patients with acquired heart disease (non-ACHD), can often be transferred to ACHD. New valve substitutes may help to reduce the number of redo operations. Most of valve operations yield good results in terms of survival and quality of life, with the precondition that the ventricular function is preserved. Heart failure due to end-stage CHD is the most frequent cause of mortality in ACHD. However, surgical treatment by means of mechanical circulatory support (MCS) is still uncommon and the mortality exceeds the one following other operations in ACHD. Currently, different devices are used and new technical developments are in progress. However, there still is no ideal assist device available. Therefore, heart transplantation remains the only valid option for end-stage CHD. Despite higher early mortality following heart transplantation in ACHD compared to non-ACHD, the long-term survival compares favorably to non-ACHD. There is room for improvement by refining the indications, the time of listing, and the perioperative care of ACHD transplant patients. Sudden death is the second most frequent cause of mortality in ACHD. Ventricular tachycardia is the most frequent cause of sudden death followed by coronary artery anomaly. Due to the increasing awareness of physicians and the improved imaging techniques, coronary artery anomalies are coming more into the focus of cardiac surgeons. However, the reported experience is limited and it is currently difficult to provide a standardized and generally applicable recommendation for the indication and the adequate surgical technique. With the increasing age and complexity of ACHD, treatment of rhythm disturbances by surgical ablation, pacemaker or implantable cardioverter defibrillator (ICD) implantation and resynchronisation gains importance. A risk score specifically designed for surgery in ACHD is among the newest developments in predicting the outcome of surgical treatment of ACHD. This evidence-based score, derived from and validated with data from the Society of Thoracic Surgeons Congenital Heart Surgery Database, enables comparison of risk-adjusted performance of the whole spectrum of procedures performed in ACHD and helps in understanding the differences in surgical outcomes. The score is thus a powerful tool for quality control and quality improvement. In conclusion, new developments in surgery for ACHD are currently made with regard to valve surgery, which comprises more than half of all operations in ACHD and in treatment of end-stage CHD, which still yields high mortality and morbidity.

Aortic Valvuloplasty or Rootplasty for Aortic Regurgitation

At present, aortic valvuloplasty is considered an effective procedure for treatment of aortic regurgitation in pediatric patients. It has encouraging mid- and long-term results. The improved outcome is primarily related to better understanding of the functional anatomy of the normal valve and the different factors that alter it. It is also related to the realization that outcome after valvuloplasty is dependent on comprehensive repair of all of the involved components of the aortic root. Refinement in preoperative diagnosis has helped identify these abnormal components and focus the surgical approach on the needed reconstruction. Although the technical aspects of valvuloplasty are well defined, suboptimal long-term results still occur in some cases because the patch material used for valve repair can become fibrotic or calcified. This review summarizes the surgical approach to and the management of the different abnormal root components in pediatric patients with significant aortic valve regurgitation.

Is Decellularized Porcine Small Intestine Sub-mucosa Patch Suitable for Aortic Arch Repair?

Introduction: We reviewed our experience with decellularized porcine small intestine sub-mucosa (DPSIS) patch, recently introduced for congenital heart defects. Materials and Methods: Between 10/2011 and 04/2016 a DPSIS patch was used in 51 patients, median age 1.1 months (5 days to 14.5 years), for aortic arch reconstruction (45/51 = 88.2%) or aortic coarctation repair (6/51 = 11.8%). All medical records were retrospectively reviewed, with primary endpoints interventional procedure (balloon dilatation) or surgery (DPSIS patch replacement) due to patch-related complications. Results: In a median follow-up time of 1.5 ± 1.1 years (0.6-2.3years) in 13/51 patients (25.5%) a re-intervention, percutaneous interventional procedure (5/51 = 9.8%) or re-operation (8/51 = 15.7%) was required because of obstruction in the correspondence of the DPSIS patch used to enlarge the aortic arch/isthmus, with median max velocity flow at Doppler interrogation of 4.0 ± 0.51 m/s. Two patients required surgery after failed interventional cardiology. The mean interval between DPSIS patch implantation and re-intervention (percutaneous procedure or re-operation) was 6 months (1-17 months). While there were 3 hospital deaths (3/51 = 5.9%) not related to the patch implantation, no early or late mortality occurred for the subsequent procedure required for DPSIS patch interventional cardiology or surgery. The median max velocity flow at Doppler interrogation through the aortic arch/isthmus for the patients who did not require interventional procedure or surgery was 1.7 ± 0.57 m/s. Conclusions: High incidence of re-interventions with DPSIS patch for aortic arch and/or coarctation forced us to use alternative materials (homografts and decellularized gluteraldehyde preserved bovine pericardial matrix).

Calcific Degeneration of CorMatrix 4 Years After Bicuspidization of Unicuspid Aortic Valve

We report the long-term outcomes of a 12-year-old boy who underwent bicuspidization of a severely stenotic unicuspid aortic valve with CorMatrix small intestinal submucosal extracellular matrix (CorMatrix Cardiovascular, Roswell, GA). CorMatrix supported favorable immediate surgical and echocardiographic outcomes and maintained stable growing functional dynamics for 2 years. At 52.5 months in situ, however, the valve failed with severe calcification, fibrosis, and retraction necessitating a redo operation. Reconstructive operations with CorMatrix are feasible, but this result questions its capacity for constructive remodeling in left-sided valve repair.