Paediatric aortic valve replacement using decellularized allografts: a multicentre update following 143 implantations and five-year mean follow-up.

OBJECTIVES: Decellularized aortic homografts (DAH) were introduced in 2008 as a further option for paediatric aortic valve replacement (AVR). METHODS: Prospective, multicentre follow-up of all paediatric patients receiving DAH for AVR in 8 European centres. RESULTS: A total of 143 DAH were implanted between February 2008 and February 2023 in 137 children (106 male, 74%) with a median age of 10.8 years (interquartile range 6.6-14.6). Eighty-four (59%) had undergone previous cardiac operations and 24 (17%) had undergone previous AVR. The median implanted DAH diameter was 21 mm (interquartile range 19-23). The median operation duration was 348 min (227-439) with a median cardiopulmonary bypass time of 212 min (171-257) and a median cross-clamp time of 135 min (113-164). After a median follow-up of 5.3 years (3.3-7.2, max. 15.2 years), the primary efficacy end-points peak gradient (median 14 mmHg, 9-28) and regurgitation (median 0.5, interquartile range 0-1, grade 0-3) showed good results but an increase over time. Freedom from death/explantation/endocarditis/bleeding/thromboembolism at 5 years were 97.8 ± 1.2/88.7 ± 3.3/99.1 ± 0.9/100 and 99.2 ± 0.8%, respectively. Freedom from death/explantation/endocarditis/bleeding/thromboembolism at 10 years were 96.3 ± 1.9/67.1 ± 8.0/93.6 ± 3.9/98.6 ± 1.4 and 86.9 ± 11.6%, respectively. In total, 21 DAH were explanted. Seven were replaced by a mechanical AVR, 1 Ross operation was performed and a re-do DAH was implanted in 13 patients with no redo mortality. The calculated expected adverse events were lower for DAH compared to cryopreserved homograft patients (mean age 8.4 years), and in the same range as for Ross patients (9.2 years) and mechanical AVR (13.0 years). CONCLUSIONS: This large-scale prospective analysis demonstrates excellent mid-term survival using DAH with adverse event rates comparable to paediatric Ross procedures.

Five-year results from a prospective, single-arm European trial on decellularized allografts for aortic valve replacement-the ARISE Study and ARISE Registry Data.

OBJECTIVES: Decellularized aortic homografts (DAH) were introduced as a new option for aortic valve replacement for young patients. METHODS: A prospective, EU-funded, single-arm, multicentre study in 8 centres evaluating non-cryopreserved DAH for aortic valve replacement. RESULTS: A total of 144 patients (99 male) were prospectively enrolled in the ARISE Trial between October 2015 and October 2018 with a median age of 30.4 years [interquartile range (IQR) 15.9-55.1]; 45% had undergone previous cardiac operations, with 19% having 2 or more previous procedures. The mean implanted DAH diameter was 22.6 mm (standard deviation 2.4). The median operation duration was 312 min (IQR 234-417), the median cardiopulmonary bypass time was 154 min (IQR 118-212) and the median cross-clamp time 121 min (IQR 93-150). No postoperative bypass grafting or renal replacement therapy were required. Two early deaths occurred, 1 due to a LCA thrombus on day 3 and 1 due ventricular arrhythmia 5 h postoperation. There were 3 late deaths, 1 death due to endocarditis 4 months postoperatively and 2 unrelated deaths after 5 and 7 years due to cancer and Morbus Wegener resulting in a total mortality of 3.47%. After a median follow-up of 5.9 years [IQR 5.1-6.4, mean 5.5 years. (standard deviation 1.3) max. 7.6 years], the primary efficacy end-points peak gradient with median 11.0 mmHg (IQR 7.8-17.6) and regurgitation of median 0.5 (IQR 0-0.5) of grade 0-3 were excellent. At 5 years, freedom from death/reoperation/endocarditis/bleeding/thromboembolism were 97.9%/93.5%/96.4%/99.2%/99.3%, respectively. CONCLUSIONS: The 5-year results of the prospective multicentre ARISE trial continue to show DAH to be safe for aortic valve replacement with excellent haemodynamics.

Matched comparison of decellularized homografts and bovine jugular vein conduits for pulmonary valve replacement in congenital heart disease.

For decades, bovine jugular vein conduits (BJV) and classic cryopreserved homografts have been the two most widely used options for pulmonary valve replacement (PVR) in congenital heart disease. More recently, decellularized pulmonary homografts (DPH) have provided an alternative avenue for PVR. Matched comparison of patients who received DPH for PVR with patients who received bovine jugular vein conduits (BJV) considering patient age group, type of heart defect, and previous procedures. 319 DPH patients were matched to 319 BJV patients; the mean age of BJV patients was 15.3 (SD 9.5) years versus 19.1 (12.4) years in DPH patients (p = 0.001). The mean conduit diameter was 24.5 (3.5) mm for DPH and 20.3 (2.5) mm for BJV (p < 0.001). There was no difference in survival rates between the two groups after 10 years (97.0 vs. 98.1%, p = 0.45). The rate of freedom from endocarditis was significantly lower for BJV patients (87.1 vs. 96.5%, p = 0.006). Freedom from explantation was significantly lower for BJV at 10 years (81.7 vs. 95.5%, p = 0.001) as well as freedom from any significant degeneration at 10 years (39.6 vs. 65.4%, p < 0.001). 140 Patients, matched for age, heart defect type, prior procedures, and conduit sizes of 20-22 mm (± 2 mm), were compared separately; mean age BJV 8.7 (4.9) and DPH 9.5 (7.3) years (p = n.s.). DPH showed 20% higher freedom from explantation and degeneration in this subgroup (p = 0.232). Decellularized pulmonary homografts exhibit superior 10-year results to bovine jugular vein conduits in PVR.

Bilateral lung transplantation for pediatric pulmonary arterial hypertension: perioperative management and one-year follow-up.

Background: Bilateral lung transplantation (LuTx) remains the only established treatment for children with end-stage pulmonary arterial hypertension (PAH). Although PAH is the second most common indication for LuTx, little is known about optimal perioperative management and midterm clinical outcomes. Methods: Prospective observational study on consecutive children with PAH who underwent LuTx with scheduled postoperative VA-ECMO support at Hannover Medical School from December 2013 to June 2020. Results: Twelve patients with PAH underwent LuTx (mean age 11.9 years; age range 1.9-17.8). Underlying diagnoses included idiopathic (n = 4) or heritable PAH (n = 4), PAH associated with congenital heart disease (n = 2), pulmonary veno-occlusive disease (n = 1), and pulmonary capillary hemangiomatosis (n = 1). The mean waiting time was 58.5 days (range 1-220d). Three patients were bridged to LuTx on VA-ECMO. Intraoperative VA-ECMO/cardiopulmonary bypass was applied and VA-ECMO was continued postoperatively in all patients (mean ECMO-duration 185 h; range 73-363 h; early extubation). The median postoperative ventilation time was 28 h (range 17-145 h). Echocardiographic conventional and strain analysis showed that 12 months after LuTx, all patients had normal biventricular systolic function. All PAH patients are alive 2 years after LuTx (median follow-up 53 months, range 26-104 months). Conclusion: LuTx in children with end-stage PAH resulted in excellent midterm outcomes (100% survival 2 years post-LuTx). Postoperative VA-ECMO facilitates early extubation with rapid gain of allograft function and sustained biventricular reverse-remodeling and systolic function after RV pressure unloading and LV volume loading.

Simultaneous Aortic and Pulmonary Valve Replacement in Repaired Congenital Heart Disease.

OBJECTIVES: Patients with congenital heart disease frequently require surgical or percutaneous interventional valve replacement after initial congenital heart defect (CHD) repair. In some of these patients, simultaneous replacement of both semilunar valves is necessary, resulting in increased procedural complexity, morbidity, and mortality. In this study, we analyze the outcomes of simultaneous aortic and pulmonary valve replacements following multiple surgical interventions for CHD. METHODS: This was a retrospective study of 24 patients who after initial repair of CHD underwent single-stage aortic and pulmonary valve replacement at our institution between 2003 and 2021. RESULTS: The mean age of the patients was 28 ± 13 years; the mean time since the last surgery was 15 ± 11 years. Decellularized valved homografts (DVHs) were used in nine patients, and mechanical valves were implanted in seven others. In eight patients, DVHs, biological, and mechanical valves were implanted in various combinations. The mean cardiopulmonary bypass time was 303 ± 104 minutes, and aortic cross-clamp time was 152 ± 73 minutes. Two patients died at 12 and 16 days postoperatively. At a maximum follow-up time of 17 years (mean 7 ± 5 years), 95% of the surviving patients were categorized as New York Heart Association heart failure class I. CONCLUSIONS: Single-stage aortic and pulmonary valve replacement after initial repair of CHD remains challenging with substantial perioperative mortality (8.3%). Nevertheless, long-term survival and clinical status at the latest follow-up were excellent. The valve type had no relevant impact on the postoperative course. The selection of the valves for implantation should take into account operation-specific factors-in particular reoperability-as well as the patients' wishes.

Surgical management of large tracheoesophageal fistula in infants after button battery ingestion.

OBJECTIVES: In recent years, an increase in severe and even fatal outcomes related to oesophageal or airway button battery (BB) ingestion by infants and small children has been reported. Extensive tissue necrosis caused by lodged BB can lead to major complications, including tracheoesophageal fistula (TEF). In these instances, best treatment remains controversial. While small defects may warrant a conservative approach, surgery often remains inevitable in highly complex cases with large TEF. We present a series of small children that underwent successful surgical management by a multidisciplinary team in our institution. METHODS: This is a retrospective analysis of n = 4 patients <18 months undergoing TEF repair from 2018 to 2021. RESULTS: Surgical repair under extracorporeal membrane oxygenation (ECMO) support was feasible in n = 4 patients by reconstructing the trachea with decellularized aortic homografts that were buttressed with pedicled latissimus dorsi muscle flaps. While direct oesophageal repair was feasible in 1 patient, 3 required esophagogastrostomy and secondary repair. The procedure was completed successfully in all 4 children with no mortality and acceptable morbidity. CONCLUSIONS: Tracheo-oesophageal repair after BB ingestion remains challenging and is associated with major morbidity. Bioprosthetic materials in conjunction with the interposition of vascularized tissue flaps between trachea and oesophagus appear to be a valid approach to manage severe cases.

Idiopathic Aneurysm of the Aortic Arch in an Infant.

Congenital aortic aneurysms are rare disorders, usually associated with genetic aortic syndromes. Here, we describe the case of an idiopathic aortic arch aneurysm which had been diagnosed prenatally by fetal echocardiography. The diagnosis was confirmed after birth in the neonatal period and successful surgical resection of the aneurysm was performed at the age of 3 months. The idiopathic etiology of the aneurysm, its localization, and the early surgical resection render this case very unusual.

German Registry for Cardiac Operations and Interventions in Patients with Congenital Heart Disease: Report 2021 and 9 Years' Longitudinal Observations on Fallot and Coarctation Patients.

BACKGROUND: The annual report of the German Quality Assurance of Congenital Heart Disease displays a broad overview on outcome of interventional and surgical treatment with respect to patient's age and risk categorization. Particular features of the German all-comers registry are the inclusion of all interventional and surgical procedures, the possibility to record repeated treatments with distinct individual patient assignment, and to record various procedures within one case. METHODS: International Pediatric and Congenital Cardiac Code terminology for diagnoses and procedures as well as classified adverse events, also recording of demographic data, key procedural performance indicators, and key quality indicators (mortality, adverse event rates). Surgical and interventional adverse events were classified according to the Society of Thoracic Surgeons and to the Congenital Heart Disease Adjustment for Risk Method of the congenital cardiac catheterization project on outcomes. Annual analysis of all cases and additional long-term evaluation of patients after repair of Fallot and primary treatment of native coarctation of the aorta were performed. RESULTS: In 2020, 5,532 patients with 6,051 cases (hospital stays) with 6,986 procedures were treated in 23 German institutions. Cases dispense on 618 newborns (10.2%), 1,532 infants (25.3%), 3,077 children (50.9%), and 824 adults (13.6%). Freedom from adverse events was 94.5% in 2,795 interventional cases, 67.9% in 2,887 surgical cases, and 42.9% in 336 cases with multiple procedures (without considering the 33 hybrid interventions). In-hospital mortality was 0.5% in interventional, 1.6% in surgical, and 5.7% in cases with multiple treatments. Long-term observation of 1,632 patient after repair of Fallot depicts the impact of previous palliation in 18% of the patients on the rate of 20.8% redo cases. Differentiated analysis of 1,864 patients with native coarctation picture clear differences of patient, age, and procedure selection and outcome. The overall redo procedure rate in this patient population is high with 30.8%. CONCLUSION: Improvement in quality of care requires detailed analysis of risks, performance indicators, and outcomes. The high necessity of redo procedures in patients with complex congenital heart disease underlines the imperative need of long-term observations.

Serial assessment of early antibody binding to decellularized valved allografts.

Objectives: Decellularized homograft valves (DHV) appear to elicit an immune response despite efficient donor cell removal. Materials and methods: A semiquantitative Dot-Blot analysis for preformed and new recipient antibodies was carried out in 20 patients following DHV implantation on days 0, 1, 7, and 28 using secondary antihuman antibodies. Immune reactions were tested against the implanted DHV as well as against the stored samples of 5 non-implanted decellularized aortic (DAH) and 6 pulmonary homografts (DPH). Results: In this study, 20 patients (3 female and 17 male patients) were prospectively included, with a median age of 18 years and an IQR of 12-30 years. Six patients received DPH and 14 received DAH. The amount of antibody binding, averaged for all patients, decreased on post-operative days 1 and 7 compared to pre-operative values; and on day 28, antibody binding reached close to pre-operative levels (16.8 ± 2.5 on day 0, 3.7 ± 1.9 on day 1, 2.3 ± 2.7 on day 7, and 13.2 ± 3.7 on day 28). In comparison with the results in healthy controls, there was a higher amount of antibody binding to DAH than to DPH. The mean number of arbitrary units was 18.4 ± 3.1 in aortic and 12.9 ± 4.5 in pulmonary DHV (p = 0.140). Male patients exhibited higher antibody binding to aortic DHV than female patients (19.5 ± 2.1 vs. 1.6 ± 6.7). The p-value calculation was limited, as only two female patients received DAH. There was no correlation between the amount of overall antibody binding to DHV with respect to donor age (Kruskal-Wallis test p = 0.550). DHV recipients with a sex mismatch to the donor showed significantly less antibody binding (6.5 ± 1.8 vs. 13.7 ± 1.8; p = 0.003). Our main finding was an increase in antibody binding in younger patients receiving decellularized aortic allografts. This increase was higher in patients with early degeneration signs but was not specific to the individual DHV implanted nor previous DHV implantation. Antibody binding toward explanted DHV was significantly increased in implicating antibody-mediated DHV degeneration. Conclusion: Serial assessment of tissue-specific antibody binding revealed an increase in some patients within 4 weeks after surgery, who subsequently developed early signs of allograft degeneration. Further studies with larger sample sizes are needed to confirm the prognostic relevance of increased antibody activity in addition to targeted research efforts to identify the molecular agents triggering this type of antibody response.

Incidence and characteristics of errors detected by a short team briefing in pediatric anesthesia.

BACKGROUND: In our institution, a modified WHO surgical safety checklist was implemented more than ten years ago. In retrospect, we noticed that pediatric anesthesia was underrepresented in our surgical safety checklist modification. Therefore, we added a standardized team briefing (pedSOAP-M) immediately before induction of anesthesia and hypothesized that the use of this checklist was effective to detect relevant errors with potentially harmful consequences. AIMS: The primary aim was to assess the incidence and characteristics of the detected errors, and the secondary aim was to identify factors influencing error detection. METHODS: This prospective observational study was performed between November 2020 and October 2021 in five operation rooms at the Children's Hospital of Hannover Medical School, Germany. The subcategories of the pedSOAP-M checklist were suction, oxygen, airway, pharmaceuticals, and monitoring. Demographic and procedure-related data and the briefing results were documented anonymously and undated, using a standardized case report form. RESULTS: We enrolled 1030 and analyzed 1025 patients (aged 0-18 years). Relevant errors were detected in 111 (10.8%) cases (suction 2.5%, oxygen 3.0%, airway 0.2%, pharmaceuticals 2.4%, monitoring 3.0%). In the pharmaceuticals subcategory, the most common error was entering a wrong patient weight into the perfusor syringe pumps. Experienced anesthetists detected significantly more errors than less experienced ones. CONCLUSION: The briefing tool pedSOAP-M was effective in detecting relevant errors with potentially harmful consequences. The presence of an experienced anesthetist was associated with a higher efficacy of the briefing. Particular attention should be given to entering patient weight into the anesthesia workstation and the perfusor syringe pumps.

5-Year results from the prospective European multi-centre study on decellularized homografts for pulmonary valve replacement ESPOIR Trial and ESPOIR Registry data.

OBJECTIVES: Early results from the prospective ESPOIR Trial have indicated excellent results for pulmonary valve replacement using decellularized pulmonary homografts (DPH). METHODS: A 5-year analysis of ESPOIR Trial patients was performed to provide an insight into the midterm DPH performance. ESPOIR Trial and Registry patients were matched with cryopreserved homografts (CH) patients considering patient age, type of heart defect and previous procedures to present the overall experience with DPH. RESULTS: A total of 121 patients (59 female) were prospectively enrolled (8/2014-12/2016), median age 16.5 years (interquartile range 11.2-29.8), and median DPH diameter 24 mm. One death (73 year-old) occurred during a median follow-up of 5.9 years (5.4-6.4), in addition to 2 perioperative deaths resulting in an overall mortality rate of 2.5%. One case of endocarditis in 637 patient-years was noticed, resulting in an incidence of 0.15% per patient-year. At 5 years, the mean peak gradient was 19.9 mmHg (9.9), mean regurgitation 0.9 (0.6, grade 0-3) and freedom from explantation/any reintervention 97.5% (1.5). The combined DPH cohort, n = 319, comprising both Trial and Registry data, showed significantly better freedom from explantation for DPH 95.5% (standard deviation 1.7) than CH 83.0% (2.8) (P < 0.001) and less structural valve degeneration at 10 years when matched to 319 CH patients [DPH 65.5% (standard deviation 4.4) and CH 47.3% (3.7), P = 0.11]. CONCLUSIONS: The 5-year data of the prospective ESPOIR Trial show excellent performance for DPH and low rates of adverse events. ESPOIR Registry data up to 15 years, including a matched comparison with CH, demonstrated statistically significant better freedom from explantation.

4D-flow cardiac magnetic resonance imaging after aortic root replacement with long-valved decellularized aortic homografts: comparison to valve-sparing aortic root replacement and healthy controls.

OBJECTIVES: Long-valved decellularized aortic homografts (DAH) may be used in young patients to treat aortic valve disease associated with aortic root dilatation, thereby eliminating the need for prosthetic material and anticoagulation. METHODS: Thirty-three male subjects in 3 equally sized cohorts were compared: patients following DAH implantation with a median age of 29 years [interquartile range (IQR) 27.5-37.5], patients post-valve-sparing aortic root replacement (VSARR), median 44 years (IQR 31.5-49) and healthy controls, median 33 years (IQR 28-40, P = 0.228). Time-resolved three-dimensional phase-contrast cardiac magnetic resonance imaging was performed to assess maximum blood flow velocity, pulse wave velocity, mechanical energy loss (EL), wall shear stress and flow patterns (vorticity, eccentricity, helicity) in 5 different planes of the aorta. RESULTS: The mean time between surgery and cardiovascular magnetic resonance was 2.56 ± 2.0 years in DAH vs 2.67 ± 2.1 in VSARR, P = 0.500. No significant differences in maximum velocity and pulse wave velocity were found between healthy controls and DAH across all planes. Velocity in the proximal aorta was significantly higher in VSARR (182.91 ± 53.91 cm/s, P = 0.032) compared with healthy controls. EL was significantly higher in VSARR in the proximal aorta with 1.85 mW (IQR 1.39-2.95) compared with healthy controls, 1.06 mW (0.91-1.22, P = 0.016), as well as in the entire thoracic aorta. In contrast, there was no significant EL in DAH in the proximal, 1.27 m/W (0.92-1.53, P = 0.296), as well as in the thoracic aorta, 7.7 m/W (5.25-9.90, P = 0.114), compared with healthy controls. There were no significant differences in wall shear stress parameters for all 5 regions of the thoracic aorta between the 3 groups. DAH patients, however, showed more vorticity, helicity and eccentricity in the ascending aorta compared with healthy controls (P < 0.019). CONCLUSIONS: Decellularized long aortic homografts exhibit near to normal haemodynamic parameters 2.5 years postoperatively compared with healthy controls and VSARR.

Indications and outcome after lung transplantation in children under 12 years of age: A 16-year single center experience.

OBJECTIVE: Paediatric lung transplantation poses unique management challenges. Experience regarding indications and outcome is scarce, especially in younger children. The primary aim of this study was to investigate outcome after first lung transplantation in children <12 years of age in comparison to adolescents (12-17 years old). METHODS: Records of patients <18 years who underwent first lung transplantation between 01/2005 and 01/2021 were retrospectively reviewed, and compared between children <12 years old and adolescents. Median (IQR) follow-up was 51 (23-91) months. RESULTS: Of the 117 patients underwent first lung transplantation at our institution, of whom 42 (35.8%) patients were <12 years and 75 (64.2%) ≥12 years old. Compared to adolescents, children were more often transplanted for interstitial lung disease (33.3% vs 12%, p = 0.005) and precapillary pulmonary hypertension (28.6% vs 12%, p = 0.025), and required more often intraoperative cardiopulmonary bypass (31% vs 14.7%, p = 0.036) and postoperative ECMO support (47.6% vs 13.3%, p < 0.001). Postoperatively, children required longer ventilation times (78 vs 18 hours, p = 0.009) and longer ICU stay (9.5 vs 3 days, p < 0.001) compared to their older counterparts. Primary graft dysfunction grade 3 at 72 hours (9.5% vs 9.3%, p = 0.999), in-hospital mortality (2.4% vs 6.7%, p = 0.418), graft survival (80% vs 62%, p = 0.479) and freedom from chronic lung allograft dysfunction (76% vs 59%, p = 0.41) at 8-year follow-up did not differ between groups. CONCLUSIONS: Lung transplantation in children under 12 years is challenging due to underlying medical conditions and operative complexity. Nevertheless, outcomes are comparable to those in older children.

Pulmonary valve prostheses: patient's lifetime procedure load and durability. Evaluation of the German National Register for Congenital Heart Defects.

OBJECTIVES: We evaluated 4384 procedures performed between 1957 and 2018, collected in the National Register for Congenital Heart Defects, conducted on 997 patients with 1823 pulmonary valve replacements (PVRs), including 226 implanted via catheter [transcatheter valve (TCV)]. Main study targets are as follows: TCV benefit, valve type durability, decade-wise treatment changes and procedure frequencies over the lifetime of a PVR patient. METHODS: We studied TCV impact on surgical valve replacement (via Kaplan-Meier); pulmonary valve type-specific performance (Kaplan-Meier and Cox regressions with age group as stratification or ordinary variable); procedure interval changes over the decades (Kaplan-Meier); procedure load, i.e. frequency of any procedure/surgical PVR/interventional or surgical PVR by patient age (multistate analyses). RESULTS: TCV performance was equivalent to surgical PVRs and extended durability significantly. Homografts were most durable; Contegras lasted comparably less in older; and Hancock devices lasted less in younger patients. Matrix P-valves showed poorer performance. Age group stratification improves the precision of valve-specific explantation hazard estimations. The current median interval between procedures is 2.6 years; it became significantly shorter in most age groups below 40 years. At 30 years, 80% of patients had undergone ≥3 procedures, 20% ≥3 surgical PVRs and 42% ≥3 surgical or interventional PVRs. CONCLUSIONS: TCVs doubled freedom from explantation of conventional valves. Homografts' age group-specific explantation hazard ratio was lowest; Matrix P's hazard ratio was highest. Age-stratified Cox regressions improve the precision of prosthesis durability evaluations. The median time between procedures for PVR patients shortened significantly to 2.6 years. At 30 years, 42% had ≥3 PVRs.

Pressure-compacted and spider silk-reinforced fibrin demonstrates sufficient biomechanical stability as cardiac patch in vitro.

OBJECTIVE: The generation of bio-/hemocompatible cardiovascular patches with sufficient stability and regenerative potential remains an unmet goal. Thus, the aim of this study was the generation and in vitro biomechanical evaluation of a novel cardiovascular patch composed of pressure-compacted fibrin with embedded spider silk cocoons. METHODS: Fibrin-based patches were cast in a customized circular mold. One cocoon of Nephila odulis spider silk was embedded per patch during the casting process. After polymerization, the fibrin clot was compacted by 2 kg weight for 30 min resulting in thickness reduction from up to 2 cm to <1 mm. Tensile strength and burst pressure was determined after 0 weeks and 14 weeks of storage. A sewing strength test and a long-term load test were performed using a customized device to exert physiological pulsatile stretching of a silicon surface on which the patch had been sutured. RESULTS: Fibrin patches resisted supraphysiological pressures of well over 2000 mmHg. Embedding of spider silk increased tensile force 1.8-fold and tensile strength 1.45-fold (p < .001), resulting in a final strength of 1.07 MPa and increased sewing strength. Storage for 14 weeks decreased tensile strength, but not significantly and suturing properties of the spider silk patches were satisfactory. The long-term load test indicated that the patches were stable for 4 weeks although slight reduction in patch material was observed. CONCLUSION: The combination of compacted fibrin matrices and spider silk cocoons may represent a feasible concept to generate stable and biocompatible cardiovascular patches with regenerative potential.

Pediatric urgent heart transplantation with age or weight mismatched donors: Reducing waiting time by enlarging donor criteria.

BACKGROUND: Despite considerable progress in heart transplantation, pediatric waiting list mortality is still high, and often patients do not have enough time to wait. We hypothesized that extending the donor criteria regarding age and weight mismatch does not significantly affect the early follow-up. METHODS: We retrospectively analyzed our pediatric heart transplantation patients operated on from 2014 to 2020 for high (>3.0) or low (<0.6) donor-recipient weight ratio (DRWR) or chronological age mismatches (donor organ >5 years older than recipient age). This patient cohort constituted "mismatched heart transplantations" (mHTX). We compared mHTX preoperative status, postoperative course, 1-year survival, and early clinical follow-up to standard pediatric heart transplantations (sHTX). RESULTS: We performed 20 pediatric heart transplantations-10 mHTX and 10 sHTX. The minimum DRWR was 0.44, the maximum was 5.60, and the maximum age mismatch was 42.6 years. Median days in the intensive care unit (p = .436) and time-to-first-rejection episode (p = .925) were comparable. Nine patients in each group were alive after 1 year, two patients were operated within 1 year of follow-up. One mHTX patient developed cardiac allograft vasculopathy after 15 months and died 648 days after transplantation (p = .237). All other patients were alive at the end of follow-up and in good clinical conditions (median follow-up for mHTX was 732.5 days, 1149.5 days for sHTX). CONCLUSION: Postoperative course and early follow-up after mHTX were comparable to sHTX. In urgent clinical situations, extended donor criteria may be considered an additional option for pediatric heart transplantation.

Valve-sparing aortic root replacement in adult patients with congenital heart disease.

OBJECTIVES: Aortic root dilatation is frequently observed in patients with congenital heart defects (CHD), but has received little attention in terms of developing a best practice approach for treatment. In this study, we analysed our experience with aortic valve-sparing root replacement in patients following previous operations to repair CHD. METHODS: In this study, we included 7 patients with a history of previous surgery for CHD who underwent aortic valve-sparing operations. The underlying initial defects were tetralogy of Fallot (n = 3), transposition of great arteries (n = 2), coarctation of the aorta (n = 1), and pulmonary atresia with ventricle septum defect (n = 1). The patients' age ranged from 20 to 40 years (mean age 31 ± 6 years). RESULTS: David reimplantation was performed in 6 patients and a Yacoub remodelling procedure was performed in 1 patient. Four patients underwent simultaneous pulmonary valve replacement. The mean interval between the corrective procedure for CHD and the aortic valve-sparing surgery was 26 ± 3 years. There was no operative or late mortality. The patient with transposition of great arteries following an arterial switch operation was re-operated 25 months after the valve-sparing procedure due to severe aortic regurgitation. In all other patients, the aortic valve regurgitation was mild or negligible at the latest follow-up (mean 8.7 years, range 2.1-15.1 years). CONCLUSIONS: Valve-sparing aortic root replacement resulted in good aortic valve function during the first decade of observation in 6 of 7 patients. This approach can offer a viable alternative to root replacement with mechanical or biological prostheses in selected patients following CHD repair.

Residual immune response towards decellularized homografts may be highly individual.

OBJECTIVES: Decellularized homograft valves (DHVs) have shown promising clinical results, particularly in the treatment of congenital heart disease. However, DHV appears to elicit an immune response in a subset of young patients, indicated by early valve degeneration. As the decellularization process is quality controlled for each DHV, we hypothesized that there may be residual immunogenicity within the extracellular matrix of DHV. METHODS: A semi-quantitative dot blot analysis was established to screen for preformed recipient antibodies using secondary anti-human antibodies. Fifteen DHV samples (7 aortic, 8 pulmonary) were solubilized and exposed to serum from 20 healthy controls. RESULTS: The sera from young controls (n = 10, 18-25 years) showed significantly stronger binding of preformed antibodies than sera from older individuals (n = 10, 48-73 years). The difference between the means of arbitrary units was 15.1 ± 6.5 (P = 0.0315). There was high intraindividual variance in the mean amounts of arbitrary units of antibody binding with some healthy controls showing >10 times higher antibody binding towards 2 different DHV. The amount of preformed antibodies bound to DHVs was higher in aortic than in pulmonary DHVs. The mean number of antibody binding (in arbitrary units) was 17.2 ± 4.5 in aortic and 14.5 ± 4.7 in pulmonary DHV (P = 0.27). The amount of preformed antibodies bound to pulmonary DHVs was statistically significantly higher in the sera of healthy males (n = 10) than in the sera of healthy females (n = 10). The mean number of arbitrary units was 17.2 ± 4.2 in male and 11.7 ± 5.3 in female sera (P = 0.036). Antibody binding to aortic DHV was also higher in males, but not significant (18.8 ± 5.0 vs 15.6 ± 4.0). Blood group (ABO) incompatibility between the serum from controls and DHV showed no impact on antibody binding, and there was no age-related impact among DHV donors. CONCLUSIONS: Residual immunogenicity of decellularized homografts appears to exist despite almost complete cell removal. The established dot blot method allows a semi-quantitative assessment of the individual immune response towards extracellular DHV components and potentially the possibility of preoperative homograft matching.

Prevention of postoperative bleeding after complex pediatric cardiac surgery by early administration of fibrinogen, prothrombin complex and platelets: a prospective observational study.

BACKGROUND: Postoperative bleeding is a major problem in children undergoing complex pediatric cardiac surgery. The primary aim of this prospective observational study was to evaluate the effect of an institutional approach consisting of early preventive fibrinogen, prothrombin complex and platelets administration on coagulation parameters and postoperative bleeding in children. The secondary aim was to study the rate of re-intervention and postoperative transfusion, the occurrence of thrombosis, length of mechanical ventilation, ICU stay and mortality. METHODS: In fifty children (age 0-6 years) with one or more predefined risk factors for bleeding after cardiopulmonary bypass (CPB), thrombelastography (TEG) and standard coagulation parameters were measured at baseline (T1), after CPB and reversal of heparin (T2), at sternal closure (T3) and after 12 h in the ICU (T4). Clinical bleeding was evaluated by the surgeon at T2 and T3 using a numeric rating scale (NRS, 0-10). RESULTS: After CPB and early administration of fibrinogen, prothrombin complex and platelets, the clinical bleeding evaluation score decreased from a mean value of 6.2 ± 1.9 (NRS) at T2 to a mean value of 2.1 ± 0.8 at T3 (NRS; P <  0.001). Reaction time (R), kinetic time (K), maximum amplitude (MA) and maximum amplitude of fibrinogen (MA-fib) improved significantly (P <  0.001 for all), and MA-fib correlated significantly with the clinical bleeding evaluation (r = 0.70, P <  0.001). The administered total amount of fibrinogen (mg kg- 1) correlated significantly with weight (r = - 0.42, P = 0.002), priming volume as percentage of estimated blood volume (r = 0.30, P = 0.034), minimum CPB temperature (r = - 0.30, P = 0.033) and the change in clinical bleeding evaluation from T2 to T3 (r = 0.71, P <  0.001). The incidence of postoperative bleeding (> 10% of estimated blood volume) was 8%. No child required a surgical re-intervention, and no cases of thrombosis were observed. Hospital mortality was 0%. CONCLUSION: In this observational study of children with an increased risk of bleeding after CPB, an early preventive therapy with fibrinogen, prothrombin complex and platelets guided by clinical bleeding evaluation and TEG reduced bleeding and improved TEG and standard coagulation parameters significantly, with no occurrence of thrombosis or need for re-operation. TRIAL REGISTRATION: German Clinical Trials Register DRKS00018109 (retrospectively registered 27th August 2019).