Trend of fetal echocardiography use and comparison of medical costs for congenital heart disease treatment based on fetal echocardiography use in a Korean single center.

Background: The rate of the prenatal diagnosis of congenital heart disease is increasing along with advances in fetal echocardiography techniques. Here, we aimed to investigate the trend of the use of fetal echocardiography over time and to compare the medical costs of congenital heart disease treatment according to whether fetal echocardiography was performed. Methods: We reviewed our hospital's database, and patients who underwent the first surgery for congenital heart disease within 30 days of birth during 2005-2007, 2011-2013, and 2017-2019 were included. The severity of congenital heart disease diagnosed in each case was evaluated according to The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery Mortality Scores (STS-EACTS Mortality Scores) and Mortality Categories (STAT Mortality Categories). Results: In total, 375 patients were analyzed, and fetal echocardiography use increased significantly after the 2010s compared with in 2005-2007 (19.1% vs. 39%, p = 0.032 in Mortality Category 1-3; 15.5% vs. 69.5%, p = 0.000 in Mortality Category 4-5). Additionally, the mean STS-EACTS Mortality Score was higher in prenatally diagnosed patients than in postnatally diagnosed patients (2.287 vs. 1.787, p = 0.001). In the recent period, there was no significant difference in hospitalization durations and medical costs according to whether or not fetal echocardiography was performed. Conclusions: This single center study showed the use of fetal echocardiography is increasing. Further, prenatal diagnosis with fetal echocardiography causing no differences in medical costs in recent years. Therefore, we suggest that fetal echocardiography can be applied more widely without increasing the economic burden.

Development of a machine learning model for the prediction of the short-term mortality in patients in the intensive care unit.

PURPOSE: The aim of this study was to develop and evaluate a machine learning model that predicts short-term mortality in the intensive care unit using the trends of four easy-to-collect vital signs. MATERIALS AND METHODS: The primary training cohort included 1968 patients at the Veterans Health Service Medical Center. The external validation cohort comprised 409 patients at Seoul National University Hospital. Datasets of heart rate, systolic blood pressure, diastolic blood pressure, and peripheral capillary oxygen saturation (SpO2) measured every hour for 10 h were used. The performances of mortality prediction models generated using five machine learning algorithms, Random Forest (RF), XGboost, perceptron, convolutional neural network, and Long Short-Term Memory, were calculated and compared using area under the receiver operating characteristic curve (AUROC) values and an external validation dataset. RESULTS: The machine learning model generated using the RF algorithm showed the best performance. Its AUROC was 0.922, which is much better than the 0.8408 of the Acute Physiology and Chronic Health Evaluation II. The machine learning model developed using SpO2 showed the best performance (AUROC, 0.89). CONCLUSIONS: This simple yet powerful new mortality prediction model could be useful for early detection of probable mortality and appropriate medical intervention, especially in rapidly deteriorating patients.

Three-Dimensional Printing of Congenital Heart Disease Models for Cardiac Surgery Simulation: Evaluation of Surgical Skill Improvement among Inexperienced Cardiothoracic Surgeons.

OBJECTIVE: To evaluate the impact of surgical simulation training using a three-dimensional (3D)-printed model of tetralogy of Fallot (TOF) on surgical skill development. MATERIALS AND METHODS: A life-size congenital heart disease model was printed using a Stratasys Object500 Connex2 printer from preoperative electrocardiography-gated CT scans of a 6-month-old patient with TOF with complex pulmonary stenosis. Eleven cardiothoracic surgeons independently evaluated the suitability of four 3D-printed models using composite Tango 27, 40, 50, and 60 in terms of palpation, resistance, extensibility, gap, cut-through ability, and reusability of. Among these, Tango 27 was selected as the final model. Six attendees (two junior cardiothoracic surgery residents, two senior residents, and two clinical fellows) independently performed simulation surgeries three times each. Surgical proficiency was evaluated by an experienced cardiothoracic surgeon on a 1-10 scale for each of the 10 surgical procedures. The times required for each surgical procedure were also measured. RESULTS: In the simulation surgeries, six surgeons required a median of 34.4 (range 32.5-43.5) and 21.4 (17.9-192.7) minutes to apply the ventricular septal defect (VSD) and right ventricular outflow tract (RVOT) patches, respectively, on their first simulation surgery. These times had significantly reduced to 17.3 (16.2-29.5) and 13.6 (10.3-30.0) minutes, respectively, in the third simulation surgery (p = 0.03 and p = 0.01, respectively). The decreases in the median patch appliance time among the six surgeons were 16.2 (range 13.6-17.7) and 8.0 (1.8-170.3) minutes for the VSD and RVOT patches, respectively. Summing the scores for the 10 procedures showed that the attendees scored an average of 28.58 ± 7.89 points on the first simulation surgery and improved their average score to 67.33 ± 15.10 on the third simulation surgery (p = 0.008). CONCLUSION: Inexperienced cardiothoracic surgeons improved their performance in terms of surgical proficiency and operation time during the experience of three simulation surgeries using a 3D-printed TOF model using Tango 27 composite.

A preclinical trial of perventricular pulmonary valve implantation: Pericardial versus aortic porcine valves mounted on self-expandable stent.

Perventricular pulmonary valve implantation (PPVI) of a xenograft valve can be a less invasive technique that avoids cardiopulmonary bypass in patients who require pulmonary valve replacement. We compared the hemodynamics, durability, and histologic changes between two different xenogenic valves (pericardial vs. aortic valve porcine xenografts) implanted into the pulmonary valve position using a PPVI technique and evaluated the safety and efficacy of PPVI as a preclinical study. In 18 sheep, pericardial (group porcine pericardial [PP], n = 9) or aortic valve (group porcine aortic valve [PAV], n = 9) xenogenic porcine valves manufactured as a stented valve were implanted using a PPVI technique. The porcine tissues were decellularized, alpha-galactosidase treated, fixed with glutaraldehyde after space-filler treatment, and detoxified to improve durability. Hemodynamic and immunohistochemical studies were performed after the implantation; radiologic and histologic studies were performed after a terminal procedure. All stented valves were positioned properly after the implantation, and echocardiography and cardiac catheterization demonstrated good hemodynamic state and function of the valves. All the anti-α-Gal IgM and IgG titers were below 0.3 optical density. Computed tomography of extracted valves demonstrated no significant differences in the degree of calcification between the two groups (P = .927). Microscopic findings revealed a minimal amount of calcification and no significant infiltration of macrophage or T-cell in both groups, regardless of the implantation duration. The PPVI is a feasible technique. Both stented valves made of PP and PAV showed no significant differences in hemodynamic profile, midterm durability, and degree of degenerative dystrophic calcification.

Changes of hospitalization trend in the pediatric cardiology division of a single center by increasing adult with congenital heart disease.

BACKGROUND: As a result of advances in pediatric care and diagnostic testing, there is a growing population of adults with congenital heart disease (ACHD). The purpose of this study was to better define the epidemiology and changes in the trend of hospitalizations for ACHD in Korean society. METHODS: We reviewed outpatient and inpatient data from 2005 to 2017 to identify patient ≥18 years of age admitted for acute care with a congenital heart disease (CHD) diagnosis in the pediatric cardiology division. We tried to analyze changes of hospitalization trend for ACHD. RESULTS: The ratio of outpatients with ACHD increased 286.5%, from 11.1% (1748/15,682) in 2005 to 31.8% (7795/24,532) in 2017. The number of ACHD hospitalizations increased 360.7%, from 8.9% (37/414) in 2005 to 32.1% (226/705) in 2017. The average patient age increased from 24.3 years in 2005 to 27.4 in 2017. The main diagnosis for admission of ACHD is heart failure, arrhythmia and Fontan-related complications. The annual ICU admission percentage was around 5% and mean length of intensive care unit (ICU) stay was 8.4 ± 14.6 days. Mean personal hospital charges by admission of ACHD increased to around two times from 2005 to 2017. (from $2578.1 to $3697.0). Total annual hospital charges by ACHD markedly increased ten times (from $95,389.7 to $831,834.2). CONCLUSIONS: The number of hospital cares for ACHD dramatically increased more than five times from 2005 to 2017. We need preparations for efficient healthcare for adults with CHD such as a multi-dimensional approach, effective communication, and professional training.

Next-generation transcatheter aortic valve implantation.

Objective: Transcatheter aortic valve implantation (TAVI) procedures are increasing rapidly, but the durability of tissue valve and periprocedural complications are not satisfactory. Immune reaction to the galactose-α-1,3 galactose ß-1,4-N-acetylglucosamine (α-Gal) and conventional processing protocols of cardiac xenografts lead to calcification. Next-generation TAVI needs to be made with α-Gal-free xenografts by multiple anticalcification therapies to avoid immune rejection and enhance durability, and three-dimensional (3D) printing technology to improve the procedural safety. Methods: Porcine pericardia were decellularized and immunologically modified with α-galactosidase. The pericardia were treated by space filler, crosslinked with glutaraldehyde in organic solvent, and detoxified. The sheep-specific nitinol (nickel-titanium memory alloy) wire backbone was made from a 3D-printed model for ovine aortic root. After it passed the fitting test, we manufactured a self-expandable stented valve with the porcine pericardia mounted on the customized nitinol wire-based stent. After in vitro circulation using customized silicone aortic root, we performed TAVI in 9 sheep and obtained hemodynamic, radiological, immunohistopathological, and biochemical results. Results: The valve functioned well, with excellent stent fitting and good coronary flow under in vitro circulation. Sheep were sequentially scheduled to be humanely killed until 238 days after TAVI. Echocardiography and cardiac catheterization demonstrated good hemodynamic status and function of the aortic valve. The xenografts were well preserved without α-Gal immune reaction or calcification based on the immunological, radiographic, microscopic, and biochemical examinations. Conclusions: We proved preclinical safety and efficacy for next-generation α-Gal-free TAVI with multiple anticalcification therapies and 3D-printing technology. A future clinical study is warranted based on these promising preclinical results.

Successful Feasibility Human Trial of a New Self-Expandable Percutaneous Pulmonary Valve (Pulsta Valve) Implantation Using Knitted Nitinol Wire Backbone and Trileaflet α-Gal-Free Porcine Pericardial Valve in the Native Right Ventricular Outflow Tract.

BACKGROUND: Self-expandable percutaneous pulmonary valve implantation (PPVI) for native right ventricular outflow tract lesions is still in the clinical trial phase. The aim of this study is to present the result of feasibility study of a novel self-expandable knitted nitinol wire stent mounted with a treated trileaflet α-Gal-free porcine pericardial valve for PPVI. METHODS AND RESULTS: A feasibility study using Pulsta valve (TaeWoong Medical Co, Gyeonggi-do, South Korea) was designed for patients with severe pulmonary regurgitation in the native right ventricular outflow tract, and 6-month follow-up outcomes were reviewed. Ten tetralogy of Fallot patients were enrolled. Before PPVI, severe pulmonary regurgitation (mean pulmonary regurgitation fraction, 45.5%±7.2%; range, 34.9%-56%) and enlarged right ventricular volume (mean indexed right ventricular end-diastolic volume, 176.7±14.3 mL/m2; range, 158.9-205.9 mL/m2) were present. The median age at PPVI was 21.7±6.5 years (range, 13-36 years). Five patients were successfully implanted with 28 mm and the other 5 with 26 mm valves loaded on the 18F delivery cable. No significant periprocedural complications were noted in any patient. At the 6-month follow-up, indexed right ventricular end-diastolic volume was dramatically decreased to 126.3±20.3 mL/m2 (range, 99-164.2 mL/m2), and the mean value of peak instantaneous pressure gradient between the right ventricle and the pulmonary artery decreased from 6.8±3.5 mm Hg (range, 2-12 mm Hg) before PPVI to 5.7±6.7 mm Hg (range, 2-12 mm Hg) without significant pulmonary regurgitation. There was no adverse event associated with the valve. CONCLUSIONS: A feasibility study of the Pulsta valve for native right ventricular outflow tract lesions was completed successfully with planned Pulsta valve implantation and demonstrated good short-term effectiveness without serious adverse events. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02555319.

Clinical Characteristics and Independent Factors Related to Long-Term Outcomes in Patients with Left Isomerism.

BACKGROUND AND OBJECTIVES: We studied the results of patient management for left isomerism (LI) and sought to determine factors that may influence survival and prognosis. SUBJECTS AND METHODS: We reviewed the medical records of 76 patients who were compatible with LI criteria between 1982 and 2014. RESULTS: Of the total study population, 29 patients (38.1%) had functional univentricular heart disease, 43 patients (56.5%) had cardiac anomalies suitable for biventricular hearts, and four patients (5.2%) had normal heart structure. Extracardiac anomalies were noted in 38.1% of the study population, including biliary atresia in 7.8% of all patients. Of the 25 patients who underwent Kawashima procedures, 24.0% developed pulmonary arteriovenous fistulas (PAVFs). During the median follow-up period of 11.4 years (range: 1 day to 32 years), 14 patients died. The 10-year, 20-year, and 30-year survival rates were 87%, 84%, and 76%, respectively. Preoperative dysrhythmia and uncorrected atrioventricular valve regurgitation were significantly associated with late death. There was no significant difference in the number of surgical procedures and in survival expectancy between patients in the functional single-ventricle group and in the biventricular group. However, late mortality was higher in functional single-ventricle patients after 18 years of age. CONCLUSION: Patients with LI need to be carefully followed, not only for late cardiovascular problems such as dysrhythmia, valve regurgitation, and the development of PAVFs, but also for noncardiac systemic manifestations.

Experience with Mechanical Circulatory Support for Medically Intractable Low Cardiac Output in a Pediatric Intensive Care Unit.

BACKGROUND AND OBJECTIVES: Mechanical circulatory support with extracorporeal membrane oxygenation (ECMO) and ventricular assist device has always been the optimal choice for treating the majority of medically intractable low cardiac output case. We retrospectively investigated our institution's outcomes and variables associated with a high risk of mortality. SUBJECTS AND METHODS: From 1999 to 2014, 86 patients who were of pediatric age or had grown-up congenital heart disease underwent mechanical circulatory support for medically intractable low cardiac output in our pediatric intensive care unit. Of these, 9 grown-up congenital heart disease patients were over 18 years of age, and the median age of the subject group was 5.82 years (range: 1 day to 41.6 years). A review of all demographic, clinical, and surgical data and survival analysis were performed. RESULTS: A total of 45 (52.3%) patients were successfully weaned from the mechanical assist device, and 25 (29.1%) survivors were able to be discharged. There was no significant difference in results between patients over 18 years and under 18 years of age. Risk factors for mortality were younger age (<30 days), functional single ventricle anatomy, support after cardiac operations, longer support duration, and deteriorated pre-ECMO status (severe metabolic acidosis and increased levels of lactate, creatinine, bilirubin, or liver enzyme). The survival rate has improved since 2010 (from 25% before 2010 to 35% after 2010), when we introduced an upgraded oxygenator, activated heart transplantation, and also began to apply ECMO before the end-stage of cardiac dysfunction, even though we could not reveal significant correlations between survival rate and changed strategies associated with ECMO. CONCLUSION: Mechanical circulatory support has played a critical role and has had a dramatic effect on survival in patients with medically intractable heart failure, particularly in recent years. Meticulous monitoring of acid-base status, laboratory findings, and early and liberal applications are recommended to improve outcomes without critical complication rates, particularly in neonates with single ventricle physiology.

Anticalcification effect of a combination of decellularization, organic solvents and amino acid detoxification on glutaraldehyde-fixed xenopericardial heart valves in a large-animal long-term circulatory model.

OBJECTIVES: We aimed to investigate the effect of a combination of anticalcification treatments, which were effective for preventing calcification in a small animal experiment, on glutaraldehyde-fixed xenopericardial valves using a large-animal long-term circulatory model. METHODS: Valved conduits were made of porcine pericardium as a leaflet and bovine pericardium as a conduit and were implanted into the right ventricular outflow tract of goats under cardiopulmonary bypass. The goats were divided into study (glutaraldehyde + combined anticalcification treatment, n = 6) and control (glutaraldehyde alone, n = 9) groups. Upon euthanization at 1 year, echocardiography and cardiac catheterization were performed. Explanted tissues were microscopically examined and analysed for measuring the calcium content. RESULTS: Haemodynamic data were obtained from 3 and 2 goats in the study and control groups, respectively. All valves, except 1, which was limited in motion, were functioning well on echocardiography; pressure gradients across the right ventricular outflow tract were lower in the study group on cardiac catheterization. On gross inspection, all leaflets remained mobile without calcific deposits in the study group, while most leaflets were heavily calcified in the control group. The calcium content in the leaflets remained low (≤4 µg/mg) in the study group. Among the leaflets explanted from goats that survived longer (>3 months), the calcium concentration was higher in the control group than in the study group [15.1 µg/mg (n = 5) vs 2.7 µg/mg (n = 5), respectively; P = 0.008). CONCLUSIONS: Porcine pericardial leaflets treated with our anticalcification protocol showed better function and less calcification than those treated with glutaraldehyde alone in the pulmonary position.

The Effects of Modification to Lateral Tunnel Fontan Procedure for Prophylactic Arrhythmia Surgery.

BACKGROUND: Refractory atrial arrhythmias and hemodynamic abnormalities are responsible for significant morbidity and mortality after the Fontan operation. We evaluated the long-term feasibility, safety, and efficacy of prophylactic atrial arrhythmia surgery performed concomitantly with the lateral tunnel Fontan operation. METHODS: From 1997 August to 2003 December, 27 patients underwent a initial lateral tunnel Fontan with an interventional atrial incision and cryoablation from the atriotomy to the coronary sinus and right atrioventricular valve annulus. This novel surgical technique consists of (1) right atriotomy extending to the coronary sinus to block the slow rate conduction isthmus; (2) cryoablation between right atriotomy and right atrioventricular valve annulus; (3) baffling to avoid injury to the crista terminalis; and (4) use of a sandwich technique with closure of right atriotomy incorporating the Gore-Tex (W. L. Gore & Associates, Flagstaff, AZ) patch to reduce atrial suture line. RESULTS: There has been no early death after operation and one late death, which was not arrhythmic in etiology. At late follow-up of 15.2 ± 2.9 years (range, 5.5 to 18.0) after Fontan, spontaneous intraatrial reentrant tachycardia occurred in 1 patient, and inducible intraatrial reentrant tachycardia in 1 patient who required beta-blocker medication without ablation attempts. There was no evidence of early or late complications related to the interventional atrial incision and cryoablation. Four patients required late pacemaker implantation for sinus node dysfunction after Fontan operation. CONCLUSIONS: The prophylactic arrhythmia surgery with our novel modification of the lateral tunnel Fontan procedure to reduce the development of intraatrial reentrant tachycardia was feasible and safe. Long-term follow-up results also demonstrated that this novel modification is effective for the prophylaxis of intraatrial reentrant tachycardia.

First in human experience of a new self-expandable percutaneous pulmonary valve implantation using knitted nitinol-wire and tri-leaflet porcine pericardial valve in the native right ventricular outflow tract.

Balloon-expandable percutaneous pulmonary valve systems using the Melody and Edwards SAPIEN transcatheter heart valves have been increasingly used instead of surgically implantable pulmonary valves. However, limited patients with right ventricular outflow tract (RVOT) lesions are suitable candidates for percutaneous pulmonary valve implantation (PPVI) using these systems after surgical correction of tetralogy of Fallot. Therefore, larger self-expandable valved-stents are being developed for native RVOT lesions. We report the first-in-human case of a new self-expandable PPVI in a patient with a native RVOT lesion using a newly made knitted nitinol-wire stent mounted with a tri-leaflet porcine pericardial valve developed in South Korea. © 2017 Wiley Periodicals, Inc.

Effects of glutaraldehyde concentration and fixation time on material characteristics and calcification of bovine pericardium: implications for the optimal method of fixation of autologous pericardium used for cardiovascular surgery.

Objectives: Autologous pericardium, which is widely used in the field of cardiovascular surgery, is usually fixed with glutaraldehyde (GA) to improve handling and provide biomechanical stability. However, an optimal method of GA fixation of autologous pericardium is not known. The objective of this study was to evaluate the effects of GA concentration and fixation time on material characteristics and calcification of bovine pericardium. Methods: Bovine pericardial tissues were fixed with different concentrations of GA (0.3, 0.4, 0.5 and 0.6%) for different exposure times (10 and 20 min). Material characteristics of the fixed tissues were assessed by mechanical test, thermal stability test and pronase test. The tissues were subcutaneously implanted into 3-week-old rats for 2 months, and the calcium contents of the explanted tissues were measured. Differences between the groups were evaluated by two-way analysis of variance. Results: Differently treated tissues showed no significant differences in tensile strength. The mean elongation at break of the pericardial tissues fixed with 0.5 and 0.6% was significantly higher compared with 0.3 and 0.4% when fixed for 20 min. The mean elongation at break of the pericardial tissues fixed for 20 min was significantly higher compared with 10 min when fixed with 0.5 and 0.6%. Thermal stability test revealed significantly higher mean shrinkage temperature of the pericardial tissues fixed with 0.6% compared with lower concentrations irrespective of fixation time. The mean shrinkage temperature of the pericardial tissues fixed for 20 min was significantly higher compared with 10 min irrespective of GA concentration. Pronase test revealed significantly lower mean percent remaining weight of the pericardial tissues fixed with 0.3% compared with higher concentrations irrespective of fixation time. The mean percent remaining weight of the pericardial tissues fixed for 20 min was significantly higher compared with 10 min irrespective of GA concentration. The mean calcium content of the pericardial tissues fixed with 0.6% was significantly lower than that of the pericardial tissues fixed with 0.4% irrespective of fixation time. Conclusions: Fixation of bovine pericardium with 0.5 and 0.6% GA for 20 min produced superior results with regard to material characteristics (mechanical properties, degree of fixation and resistance to enzymatic degradation) and postimplantation calcification. These results may have implications for optimal fixation of autologous pericardium used for cardiovascular surgery.

The Immune Responses and Calcification of Bioprostheses in the α1,3-Galactosyltransferase Knockout Mouse.

BACKGROUND: The study aim was to evaluate the immune reaction, difference of degenerative calcification, and anti-calcification effect of decellularization with or without α-galactosidase in bovine pericardium and porcine heart valves, using an α1,3-galactosyltransferase (α-Gal) knockout (KO) mouse model. METHODS: In order to elucidate the anti-calcification effect of decellularization with or without α-galactosidase, bovine pericardium and porcine heart valve tissues were assigned to four groups according to the tissue preparation method: (i) glutaraldehyde (GA) fixation only; (ii) decellularization + GA fixation (Decell); (iii) α-galactosidase + GA fixation (α-galactosidase); and (iv) decellularization +α-galactosidase + GA fixation (Decell + α-galactosidase). Each prepared tissue was implanted subcutaneously into α-Gal KO mice. Anti-α-Gal immunoglobulin (Ig) G and IgM antibody titers were monitored prior to implantation and at four, eight and 12 weeks after implantation using an enzyme-linked immunosorbent assay. Calcium contents of explanted tissues were measured at 12 weeks after implantation. RESULTS: There were no significant differences in the anti-α-Gal IgG antibody titers according to the type of bioprosthetic material or tissue preparation method (p >0.05). The calcium content was significantly lower in porcine heart valves than in bovine pericardium when implanted in α-Gal-KO mice (p <0.001). Calcium contents in bovine pericardium and porcine heart valves were significantly lower in the Decell, α-galactosidase and Decell + α-galactosidase groups than in the GA group (all p <0.05). CONCLUSIONS: The porcine heart valve induced lower levels of calcium deposition than did the bovine pericardium, but the anti-α-Gal IgG antibody titers did not differ significantly between the bioprosthetic tissues. Decellularization had significant anticalcification effects in both the bovine pericardium and porcine heart valves, though there was no significant difference in the anti-α-Gal IgG antibody titers among tissue preparation methods.

Long-Term Results after Surgical Treatment of Ebstein's Anomaly: a 30-year Experience.

BACKGROUND AND OBJECTIVES: The aim of the study is to evaluate the long-term results after a surgical repair of Ebstein's anomaly. SUBJECTS AND METHODS: Forty-eight patients with Ebstein's anomaly who underwent open heart surgery between 1982 and 2013 were included. Median age at operation was 5.6 years (1 day-42.1 years). Forty-five patients (93.7%) demonstrated tricuspid valve (TV) regurgitation of less than moderate degree. When the patients were divided according to Carpentier's classification, types A, B, C, and D were 11, 21, 12, and 4 patients, respectively. Regarding the type of surgical treatment, bi-ventricular repair (n=38), one-and-a half ventricular repair (n=5), and single ventricle palliation (n=5) were performed. Of 38 patients who underwent a bi-ventricular repair, TV repairs were performed by Danielson's technique (n=20), Carpentier's technique (n=11), Cone repair (n=4), and TV annuloplasty (n=1). Two patients underwent TV replacement. Surgical treatment strategies were different according to Carpentier's types (p<0.001) and patient's age (p=0.022). RESULTS: There were 2 in-hospital mortalities (4.2%; 1 neonate and 1 infant) and 2 late mortalities during follow-up. Freedom from recurrent TV regurgitation rates at 5, 10, and 15 years were 88.6%, 66.3%, 52.7%, respectively. TV regurgitation recurrence did not differ according to surgical method (p=0.800). Survival rates at 5, 10, and 20 years were 95.8%, 95.8%, and 85.6%, respectively, and freedom from reoperation rates at 5, 10, and 15 years were 85.9%, 68.0%, and 55.8%, respectively. CONCLUSION: Surgical treatment strategies were decided according to Carpentier's type and patient's age. Overall survival and freedom from reoperation rates at 10 years were 95.8% and 68.0%, respectively. Approximately 25% of patients required a second operation for TV during the follow-up.

Calcification of decellularized and alpha-galactosidase-treated bovine pericardial tissue in an alpha-Gal knock-out mouse implantation model: comparison with primate pericardial tissue.

OBJECTIVES: Immune reaction against the α-Gal(Galα1,3-Galß1-4GlcNAc-R) epitope is known to be one of the important factors for calcification of bioprostheses. The genetically manipulated α-Gal knock-out (KO) mice lacking the α-Gal epitope and containing anti-α-Gal antibodies may simulate an immune response against xenoantigens in primates including humans. The aims of this study were (i) to compare calcification and immune reactions of glutaraldehyde (GA)-fixed bovine with primate pericardium and (ii) to assess the differences in bovine pericardium treated with decellularization and α-galactosidase, using an α-Gal KO mouse implantation model. METHODS: Four types of GA-fixed xenogeneic tissues were implanted into α-Gal KO mice for 16 weeks (Group 1: primate pericardium, n = 14; Group 2: bovine pericardium, n = 19; Group 3: decellularized bovine pericardium, n = 20; Group 4: decellularized and α-galactosidase-treated bovine pericardium, n = 21). Serum enzyme-linked immunosorbent assays for immune response were performed before implantation and 2, 4, 8, 12 and 16 weeks after implantation. Implanted tissues were harvested and studied for histopathology and quantification of calcification. RESULTS: Anti-α-Gal IgG antibody titres of Groups 2-4 increased after implantation although the titres did not change in Group 1. When compared with preimplantation titres, the increased IgG titres were highest at 8 weeks after implantation in Groups 2-4 (0.4358 ± 0.0524 vs 0.5462 ± 0.0519 in Group 2, 0.4712 ± 0.0500 vs 0.6424 ± 0.0613 in Group 3 and 0.4892 ± 0.0801 vs 0.6112 ± 0.0339 in Group 4; P = 0.028 in each group). Median calcium levels were higher in Group 2 than in Group 1 (9.21 vs 3.86 µg/mg, P < 0.001), but were not significantly higher in Groups 3 and 4 than in Group 1 (4.09 µg/mg in Group 3, P = 0.904; 5.47 µg/mg in Group 4, P = 0.210). CONCLUSIONS: GA-fixed bovine pericardium showed higher calcium levels than primate pericardium. Increased IgG antibody titres in the bovine but not in the primate group suggested that an immune response was involved in implanted tissue. Differences in calcium levels of bovine pericardium treated with decellularization and α-galactosidase were insignificant compared with primate pericardium, suggesting those treatments to be effective methods in preventing calcification of the bioprostheses.

Potts shunt in patients with primary pulmonary hypertension.

Idiopathic pulmonary arterial hypertension eventually leads to right-sided heart failure and sudden death. Its mortality rate in children is still high, despite improvements in pharmacological therapy, and therefore novel treatments are necessary. The Potts shunt, which creates an anastomosis between the left pulmonary artery and the descending aorta, has been proposed as a theoretically promising palliative surgical technique to decompress the right ventricle. We report the case of a 12-year-old girl with suprasystemic idiopathic pulmonary hypertension and right ventricular failure who underwent a Potts shunt for palliation with good short-term results.

Differences in xenoreactive immune response and patterns of calcification of porcine and bovine tissues in α-Gal knock-out and wild-type mouse implantation models.

OBJECTIVES: Although bioprostheses are widely used in cardiovascular surgery, their durability is limited due to degeneration. Degeneration of bioprostheses limiting its clinical use results from multiple factors, and immune reaction has been considered to be one of the most important factors. The study objectives were to compare the mechanical characteristic differences of porcine and bovine prostheses, assess the differences in immune reaction among different species and tissues as well as elucidate bioprosthetic failure patterns in α-Gal knock-out (KO) and wild-type mouse implantation models. METHODS: Six groups of different xenogeneic tissues (porcine pericardium, aortic valve, aortic wall; bovine pericardium, aortic valve and aortic wall) were implanted into the subcutaneous tissue of the wild-type mouse (n = 4) and the KO mouse (n = 4) (four xenogeneic tissue segments per each mouse). Mechanical and chemical tests, including tensile strength measurement and thermal stability test for pericardial tissues and pronase test for different xenogeneic tissues, were performed before implantation. Anti-α-Gal antibody titres (IgM and IgG antibodies) were measured using serum enzyme-linked immunosorbent assay analyses before implantation and 30, 60 and 90 days after implantation. Implanted tissues were harvested after 90 days and studied for histopathology and quantification of calcification. RESULTS: There were no significant differences in tensile strength and shrinkage temperature between the porcine and bovine pericardia, although the bovine pericardia showed a greater elasticity than the porcine pericardia (elongation at tensile strength, 74.8 ± 4.5% vs 50.0 ± 8.7%, P < 0.001). Resistance towards pronase degradation was not different among the groups of tissues (Groups 1-6, 89.1 ± 7.6, 95.1 ± 1.8, 90.3 ± 5.3, 93.7 ± 3.3, 89.1 ± 2.4 and 89.1 ± 3.0%, respectively; P = 0.061). The IgM titres of the α-Gal KO mice were significantly higher at 30 days after implantation (0.71 ± 0.27 vs 1.07 ± 0.48, P = 0.004), whereas the IgG titres of the α-Gal KO mice remained higher until 60 days after implantation (at 30 days, 0.81 ± 0.07 vs 1.28 ± 0.79, P = 0.017; at 60 days, 0.54 ± 0.16 vs 1.43 ± 1.10, P = 0.045) than those of the wild-type mice. Calcium levels of tissues implanted into the α-Gal KO mice were significantly higher than those implanted into the wild-type mice regardless of tissue type (from Groups 1-6, 4.72 ± 1.75 vs 27.76 ± 22.73 µg/mg; 3.05 ± 1.04 vs 15.90 ± 6.98 µg/mg; 2.13 ± 1.48 vs 29.76 ± 30.71 µg/mg; 1.02 ± 0.53 vs 5.97 ± 1.40 µg/mg; 3.18 ± 3.41 vs 30.55 ± 66.69 µg/mg; 6.21 ± 5.56 vs 21.65 ± 17.77 µg/mg, all P ≤ 0.002). CONCLUSIONS: Chronic immune response to the α-Gal antigen may cause more severe tissue calcification in α-Gal KO mice. Removal of α-Gal antigenicity is strongly advised in xenogeneic bioprosthetic tissue implantation.

In vivo efficacy for novel combined anticalcification treatment of glutaraldehyde-fixed cardiac xenograft using humanized mice.

The animal immune response against Galα1,3-Galß1-4GlcNAc-R(α-Gal) epitopes gives an important cause for the failure of glutaraldehyde(GA)-fixed cardiac xenografts. This study aimed to assess the in vivo effect of our novel combined anticalcification treatment, which includes immunologic modification, using α1,3-galactosyltransferase knock-out mice to mimic human immunologic environment. Bovine pericardia were cross-linked with GA and treated with decellularization, immunologic modification with α-galactosidase, space-filler with polyethylene glycol, organic solvent, and detoxification. The bovine pericardia were subcutaneously implanted into humanized and wild type mice, and titers of anti α-Gal IgM and IgG were evaluated at various time intervals. In vivo calcification and immunohistochemistry staining was assessed for the explanted xenografts several months after implantation. In humanized mice, titers for anti α-Gal IgM and IgG increased as the period of implantation increased, and reduced with our anticalcification treatments. The humanized mice had more in vivo calcification in GA-fixed xenografts treated with our anticalcification protocol compared with wild type mice. In humanized mice, in vivo calcification reduced with our combined anticalcification treatment, and the immunohistochemistry of the harvested xenografts proved the compatible findings with the results of in vivo immunogenicity and calcification. Humanized mice are effective model for the assessment of in vivo calcification, and our combined anticalcification treatments reduced in vivo calcification as well as in vivo immunogenicity in humanized mice group, suggesting that the animal immune reaction is the cause for calcification. Our novel combined anticalcification strategies of decellularization, immunologic modification, space-filler, organic solvent, and detoxification have possible promise to prolong the lifespan of cardiac xenograft.