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Cardiac valvular surgery in patients after lung transplantation is a challenging procedure, reports are scarce. We report a 29-year-old patient who underwent concomitant mitral valve reconstruction and implantation of a decellularized aortic homograft two years after bilateral lung transplantation.

Abstract Background Acute kidney injury (AKI) following cardiac surgery is a frequent complication and several risk factors increasing its incidence have already been characterized. This study evaluates the influence of preoperative increased serum uric acid (SUA) levels in comparison with other known risk factors on the incidence of AKI following cardiac surgery. Methods During a period of 5 month, 247 patients underwent elective coronary artery bypass grafting, valve replacement/ repair or combined bypass and valve surgery. Datas were prospectively analyzed. Primary endpoint was the incidence of AKI as defined by the AKI criteria comparing patients with preoperative serum uric acid (SUA) levels below versus above the median. Multivariate logistic regression analysis was used to identify independent predictors of postoperative AKI. Results Thirty (12.1%) of the 247 patients developed postoperative AKI, 24 of 30 (80%) had preoperative SUA- levels above the median (≥373 μmol/l) (OR: 4.680, CI 95% 1.840; 11.904, p = 0.001). In the multivariate analysis SUA levels above the median (OR: 5.497, CI 95% 1.772; 17.054, p = 0.003), cardiopulmonary bypass (CPB) time > 90 min (OR: 4.595, CI 95% 1.587; 13.305, p = 0.005), cardiopulmonary bypass (CPB) > 30 kg/m2 (OR: 3.208, CI 95% 1.202; 8.562; p = 0.02), and preoperative elevated serum-creatinine levels (OR: 1.015, CI 95% 1.001; 1.029, p = 0.04) were independently associated with postoperative AKI. Conclusions Serum uric acid is an independent risk marker for AKI after cardiac surgery. From all evaluated factors it showed the highest odds ratio.

Aim. Development of the tissue engineered matrix for the atrioventricular valve graft in a large animal model. Materials and мethods. The study was performed on ovine mitral valves (n = 100). The decellularization of the whole mitral valve grafts was performed using 21 different detergent-based protocols. The effectiveness of the decellularization was investigated by immunofluorescent staining for DNA (as a marker of intracellular antigens) and α-GAL (as a marker of membrane-associated antigens), as well as DNA quantification. The mechanical properties and the repopulation potential were analyzed. The structure and repopulation rate analysis included hematoxylin-eosin, Movat’s pentachrome and Van Gieson histological staining, and immunofluorescent staining for collagen I and IV, as well as endothelial cell markers. Results. The protocols that included the gradual rise of the detergent solution were shown to be the most effective for the decellularization of the whole mitral valve graft. At the same time, the detergents alone failed to remove α-GAL. The reducing agent enhanced the decellularization, which resulted in complete removal of DNA and α-GAL, according to immunofluorescent staining. DNA quantification showed a 96.4% reduction in DNA content. The mechanical properties were shown to be comparable to the native tissue. The reseeding of the decellularized tissue showed a potential for the repopulation. Conclusions. A new matrix for the atrioventricular valve substitute could be developed using the decellularization as the initial step of the valve tissue engineering. The detergent combined with a reducing agent showed significantly better results compared to the detergents alone for the mitral valve decellulrization. The matrix demonstrated mechanical properties, comparable with the native one, and the potential for the repopulation.

Abstract Background Metabolic syndrome (MetS) is associated with an increased risk for cardiovascular events and high socioeconomic costs. Despite lifestyle interventions focusing on exercise are effective strategies to improve parameters of the above aspects, many programs fail to show sustained effects in the long-term. Methods At visit 2 (V2) 129 company employees with diagnosed MetS, who previously participated in a 6-month telemonitoring-supported exercise intervention, were randomized into three subgroups for a 6-month maintenance treatment phase. A wearable activity device was provided to subgroup A and B to assess and to track physical activity. Further subgroup A attended personal consultations with individual instructions for exercise activities. Subgroup C received neither technical nor personal support. 6 months later at visit (V3), changes in exercise capacity, MetS severity, work ability, health-related quality of life and anxiety and depression were compared between the subgroups with an analysis of variance with repeated measurements. Results The total physical activity (in MET*h/week) declined between visit 2 and visit 3 (subgroup A: V2: 48.0 ± 33.6, V3: 37.1 ± 23.0; subgroup B: V2: 52.6 ± 35.7, V3: 43.8 ± 40.7, subgroup C: V2: 51.5 ± 29.7, V3: 36.9 ± 22.8, for all p = 0.00) with no between-subgroup differences over time (p = 0.68). In all three subgroups the initial improvements in relative exercise capacity and MetS severity were maintained. Work ability declined significantly in subgroup C (V2: 40.3 ± 5.0, V3: 39.1 ± 5.7; p

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. Conclusion 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. [ABSTRACT FROM AUTHOR]

Immune rejection remains the major obstacle to long-term survival of allogeneic lung transplants. The expression of major histocompatibility complex molecules and minor histocompatibility antigens triggers allogeneic immune responses that can lead to allograft rejection. Transplant outcomes therefore depend on long-term immunosuppression, which is associated with severe side effects. To address this problem, we investigated the effect of genetically engineered transplants with permanently down-regulated swine leukocyte antigen (SLA) expression to prevent rejection in a porcine allogeneic lung transplantation (LTx) model. Minipig donor lungs with unmodified SLA expression (control group, n = 7) or with modified SLA expression (treatment group, n = 7) were used to evaluate the effects of SLA knockdown on allograft survival and on the nature and strength of immune responses after terminating an initial 4-week period of immunosuppression after LTx. Genetic engineering to down-regulate SLA expression was achieved during ex vivo lung perfusion by lentiviral transduction of short hairpin RNAs targeting mRNAs encoding β2-microglobulin and class II transactivator. Whereas all grafts in the control group were rejected within 3 months, five of seven animals in the treatment group maintained graft survival without immunosuppression during the 2-year monitoring period. Compared with controls, SLA-silenced lung recipients had lower donor-specific antibodies and proinflammatory cytokine concentrations in the serum. Together, these data demonstrate a survival benefit of SLA–down-regulated lung transplants in the absence of immunosuppression. Editor's summary: Solid organ transplants have saved the lives of many with late-stage organ failure. However, the need to match major histocompatibility complex (MHC) molecules reduces the number of donor-recipient pairs and results in long waits for donor organs. A strategy to avoid the need for MHC matching is to knock down MHC expression in the transplanted organ altogether. Here, Figueiredo et al. transplanted lungs that underwent gene engineering to knock down MHC expression in recipient pigs. This approach, which relied on lentiviral vectors carrying shRNAs against B2M and CIITA, effectively hid the donor lungs from the immune system, enabling long-term graft survival. Together, these results suggest that MHC knockdown may be a feasible strategy to improve graft survival after solid organ transplantation. —Courtney Malo [ABSTRACT FROM AUTHOR]

The pathophysiology of pulmonary hypertension (PH) is not fully understood. Here, we tested the hypothesis that hypoxic perfusion of the vasa vasorum of the pulmonary arterial (PA) wall causes PH. Young adult pig lungs were explanted and placed into a modified ex vivo lung perfusion unit (organ care system, OCS) allowing the separate adjustment of parameters for mechanical ventilation, as well as PA perfusion and bronchial arterial (BA) perfusion. The PA vasa vasorum are branches of the BA. The lungs were used either as the control group (n = 3) or the intervention group (n = 8). The protocol for the intervention group was as follows: normoxic ventilation and perfusion (steady state), hypoxic BA perfusion, steady state, and hypoxic BA perfusion. During hypoxic BA perfusion, ventilation and PA perfusion maintained normal. Control lungs were kept under steady-state conditions for 105 min. During the experiments, PA pressure (PAP) and blood gas analysis were frequently monitored. Hypoxic perfusion of the BA resulted in an increase in systolic and mean PAP, a reaction that was reversible upon normoxic BA perfusion. The PAP increase was reproducible during the second hypoxic BA perfusion. Under control conditions, the PAP stayed constant until about 80 min of the experiment. In conclusion, the results of the current study prove that hypoxic perfusion of the vasa vasorum of the PA directly increases PAP in an ex situ lung perfusion setup, suggesting that PA vasa vasorum function and wall ischemia may contribute to the development of PH. NEW & NOTEWORTHY Hypoxic perfusion of the vasa vasorum of the pulmonary artery directly increased pulmonary arterial pressure in an ex vivo lung perfusion setup. This suggests that the function of pulmonary arterial vasa vasorum and wall ischemia may contribute to the development of pulmonary hypertension. [ABSTRACT FROM AUTHOR]

Abstract Background α1-Antitrypsin (AAT) is an acute phase glycoprotein, a multifunctional protein with proteinase inhibitory, anti-inflammatory and cytoprotective properties. Both preclinical and clinical experiences show that the therapy with plasma purified AAT is beneficial for a broad spectrum of inflammatory conditions. The potential effects of AAT therapy have recently been highlighted in lung transplantation (LuTx) as well. Methods We used a murine fully mismatched orthotopic single LuTx model (BALB/CJ as donors and C57BL/6 as recipients). Human AAT preparations (5 mg, n = 10) or vehicle (n = 5) were injected to the recipients subcutaneously prior to and intraperitoneally immediately after the LuTx. No immune suppressive drugs were administered. Three days after the transplantation, the mice were sacrificed, and biological samples were assessed. Results Histological analysis revealed significantly more severe acute rejection in the transplanted lungs of controls than in AAT treated mice (p

Heart valve tissue engineering aims at creating living valves through colonization of scaffolds with patient’s own cells. Various cell sources have been explored focusing mainly on endothelialization of the scaffold surface. Endothelial like cells, such as endothelial progenitor cells (EPCs), which can be isolated from peripheral blood or bone marrow could be a suitable option. In this study we investigated cell colonization potential of ovine EPCs (OEPCs) on thermoplastic silicone-based polyurethane (TSPU) polymer scaffolds. TSPU nonwovens with and without vascular endothelial growth factor (VEGF) functionalization were used. SEM images showed that by day 3 the cells were growing as patches on the surface of both polymer groups. The cell patches continued growing and started covering more of the nonwoven surface. On day 7 the cells had almost covered the scaffold surface. The cells were more uniformly distributed as monolayer on the functionalized TSPU compared to the non-functionalized nonwovens. Live/Dead staining provided bright green fluorescence on the samples, indicating metabolically active alive cells. These static cell seeding experiments demonstrated that functionalized TPSU nonwovens support endothelialization. The feasibility of TPSU nonwovens as heart valve prosthesis scaffold could be further explored with animal studies in an ovine model.

ObjectivesAortic valve sparing-aortic root replacement (David procedure) has not been routinely performed via minimally invasive access due to its complexity. We compared our results of elective David procedure via minimally invasive access to those via a full sternotomy.MethodsBetween 1993 and 2019, a total of 732 patients underwent a valve sparing root replacement (David) procedure. Out of these, 220 patients underwent elective David-I procedure (isolated) without any other concomitant procedures at our center. Patients were assigned to either group A (n = 42, mini-access) or group B (n = 178, full sternotomy).ResultsCardiopulmonary bypass time were 188.5 ± 35.4 min in group A and 149.0 (135.5–167.5) in group B (p < 0.001). Aortic cross-clamp time were 126.2 ± 27.2 min in group A and 110.0 (97.0–126.0) in group B (p < 0.001). Post-operative echocardiography showed aortic insufficiency ≤ I° in 41 (100%) patients of group A and 155 (95%) of group B. In-hospital mortality was 2.4% (n = 1) in group A and 0% (n = 0) in group B (p = 0.191). Perioperative stroke occurred in 1 (2.4%) patient of group A and 2 (1.1%) patients of group B (p = 0.483). Reexploration for bleeding was necessary in 4 (9.5%) patients of group A and 7 (3.9%) of group B (p = 0.232). Follow-up was complete for 98% of all patients. The 1-, 2-, 4-, and 6-year survival rates were: 97, 97, 97, and 97%, in group A (mini-access) and 99, 96, 95, and 92% in group B (full sternotomy), respectively. The rates for freedom from valve-related re-operation at 1, 2, 4, and 6 years after initial surgery were: 97, 95, 95, and 84% in group A and 97, 95, 91, and 90% in group B, respectively.ConclusionEarly post-operative results after David procedure via minimally invasive access are comparable to conventional full sternotomy. Meticulous attention to hemostasis is a critical factor during minimally access David procedures. Long-term outcome including the durability of the reimplanted aortic valve seems to be comparable, too.

Abstract Background In spite of renal graft shortage and increasing waiting times for transplant candidates, simultaneous heart and kidney transplantation (HKTx) is an increasingly performed procedure established for patients with combined end-stage cardiac and renal failure. Although data on renal graft outcome in this setting is limited, reports on reduced graft survival in comparison to solitary kidney transplantation (KTx) have led to an ongoing discussion of adequate organ utilization. Methods This retrospective study was conducted to evaluate prognostic factors and outcomes of 27 patients undergoing HKTx in comparison to a matched cohort of 27 patients undergoing solitary KTx between September 1987 and October 2019 in one of Europe’s largest transplant centers. Results Median follow-up was 100.33 (0.46–362.09) months. Despite lower five-year kidney graft survival (62.6% versus 92.1%; 111.73 versus 183.08 months; p = 0.189), graft function and patient survival (138.90 versus 192.71 months; p = 0.128) were not significantly inferior after HKTx in general. However, in case of prior cardiac surgery requiring sternotomy we observed significantly reduced early graft and patient survival (57.00 and 94.09 months, respectively) when compared to patients undergoing solitary KTx (183.08 and 192.71 months; p

Abstract Background Extracorporeal life support (ECLS) is an established tool to stabilize severely ill patients with therapy-refractory hemodynamic or respiratory failure. Recently, we established a mobile ECLS retrieval service at our institution. However, data on the outcome of patients receiving ECLS at outside hospitals for transportation into tertiary hospitals is still sparse. Methods We have analyzed all patients receiving ECLS in outside hospitals (Transport group, TG) prior to transportation to our institution and compared the outcome to our in-house ECLS experience (Home Group, HG). Results Between 2012 and 2018, we performed 978 ECLS implantations, 243 of which were performed on-site in tertiary hospitals for ECLS supported transportation. Significantly more veno-venous systems were implanted in TG (n = 129 (53%) vs. n = 327 (45%), p = 0.012). Indication for ECLS support differed between the groups, with more pneumonia; acute respiratory distress syndromes in the TG group and of course, more postcardiotomy patients in HG. Mean age was 47 (± 20) (HG) vs. 48 (± 18) (TG) years, p = 0.477 with no change over time. No differences were seen in ECLS support time (8.03 days ±8.19 days HG vs 7.81 days ±6.71 days TG, p = 0.675). 30-day mortality (n = 379 (52%) (HG) vs. n = 119 (49%) (TG) p = 0.265) and death on ECLS support (n = 322 (44%) (HG) vs. n = 97 (40%) TG, p = 0.162) were comparable between the two groups, despite a more severe SAVE score in the v-a TG (HG: − 1.56 (± 4.73) vs. TG -3.93 (± 4.22) p

Introduction: Acute type A aortic dissection (ATAAD) is one of the most critical emergencies in cardiovascular surgery. Additional complications such as organ malperfusion can significantly decrease the chances of survival. Despite promptly performed surgical treatment, impaired organ perfusion may persist, thus close postoperative monitoring is recommended. But, is there a surgical consequence due to the existence of a preoperatively known malperfusion and is there a correlation between pre-, peri- and postoperative levels of serum lactate and proven malperfusion? Methods: Between 2011 and 2018, 200 patients (66% male; median age: 62.5 years; interquartile range: +/−12.4 years) that received surgical treatment at our institution for an acute dissection DeBakey type I were enrolled in this study. The cohort was divided into two groups according to the preoperative existence of malperfusion and non-malperfusion. At least one kind of malperfusion occurred in 74 patients (Group A: 37%), while 126 patients (Group B: 63%) showed no evidence of malperfusion. Furthermore, lactate levels of both cohorts were differentiated into four periods: preoperative, intraoperative, 24 hours after surgery, and 2–4 days after surgery. Results: The patients' status differed significantly prior to surgery. Group A (malperfusion) showed an elevated requirement for mechanical resuscitation (A: 10.8%; B: 5.6%; p : 0.173), were significantly more often admitted in an intubated state (A: 14.9%; B: 2.4%; p : 0.001) and showed higher incidences of stroke (A: 18.9% (n = 149); B: 3.2% (n = 4); p : 0.001). Levels of serum lactate from the preoperative period until days 2–4 were significantly increased in the malperfusion cohort at all times. Conclusions: Preexisting malperfusion due to ATAAD may significantly increase the chance of early mortality in patients with ATAAD. Serum lactate levels were a reliable marker for inadequate perfusion from admission until day 4 after surgery. Despite this, early intervention survival in this cohort remains limited. [ABSTRACT FROM AUTHOR]

Background: Experimental coronary artery interventions are currently being performed on non-diseased blood vessels in healthy animals. To provide a more realistic pathoanatomical scenario for investigations on novel interventional and surgical therapies, we aimed to fabricate a stenotic lesion, mimicking the morphology and structure of a human atherosclerotic plaque. Methods: In an interdisciplinary setting, we engineered a casting mold to create an atherosclerotic plaque with the dimensions to fit in a porcine coronary artery. Oscillatory rheology experiments took place along with long-term stability tests assessed by microscopic examination and weight monitoring. For the implantability in future in vivo setups, we performed a cytotoxicity assessment, inserted the plaque in resected pig hearts, and performed diagnostic imaging to visualize the plaque in its final position. Results: The most promising composition consists of gelatin, cholesterol, phospholipids, hydroxyapatite, and fine-grained calcium carbonate. It can be inserted in the coronary artery of human-sized pig hearts, producing a local partial stenosis and interacting like the atherosclerotic plaque by stretching and shrinking with the vessel wall and surrounding tissue. Conclusion: This artificial atherosclerotic plaque model works as a simulating tool for future medical testing and could be crucial for further specified research on coronary artery disease and is going to help to provide information about the optimal interventional and surgical care of the disease. [ABSTRACT FROM AUTHOR]

BackgroundAcute kidney injury (AKI) after lung transplantation (LuTx) is associated with increased long-term mortality. In this prospective observational study, commonly used AKI-definitions were examined regarding prediction of long-term mortality and compared to simple use of the serum creatinine value at day 7 for patients who did not receive hemodialysis, and serum creatinine value immediately before initiation of hemodialysis (d7/preHD-sCr).Methods185 patients with LuTx were prospectively enrolled from 2013-2014 at our center. Kidney injury was assessed within 7 days by: (1) the Kidney Disease Improving Global Outcomes criteria (KDIGO-AKI), (2) the Acute Disease Quality Initiative 16 Workgroup classification (ADQI-AKI) and (3) d7/preHD-sCr. Prediction of all-cause mortality was examined by Cox regression analysis, and clinical as well as laboratory factors for impaired kidney function post-LuTx were analyzed.ResultsAKI according to KDIGO and ADQI-AKI occurred in 115 patients (62.2%) within 7 days after LuTx. Persistent ADQI-AKI, KDIGO-AKI stage 3 and higher d7/preHD-sCr were associated with higher mortality in the univariable analysis. In the multivariable analysis, d7/preHD-sCr in combination with body weight and intra- and postoperative platelet transfusions predicted mortality after LuTx with similar performance as models using KDIGO-AKI and ADQI-AKI (concordance index of 0.75 for d7/preHD-sCr vs., 0.74 and 0.73, respectively). Pre-transplant reduced renal function, diabetes, higher BMI, and intraoperative ECMO predicted higher d7/preHD-sCr (r2 = 0.354, p < 0.001).ConclusionOur results confirm the importance of AKI in lung transplant patients; however, a simple and pragmatic indicator of renal function, d7/preHD-sCr, predicts long-term mortality equally reliable as more complex AKI-definitions like KDIGO and ADQI.

Abstract Background Limb loss has a drastic impact on a patient’s life. Severe trauma to the extremities is common in current military conflicts. Among other aspects, “life before limb” damage control surgery hinders immediate replantation within the short post-traumatic timeframe, which is limited in part by the ischemic time for successful replantation. Ex vivo limb perfusion is currently being researched in animal models and shows promising results for its application in human limb replantation and allotransplantation. Presentation of the hypothesis The current lack of replantation possibilities in military operations with high rates of amputation can be addressed with the development of a portable ex vivo limb perfusion device, as there are several opportunities present with the introduction of this technique on the horizon. We hypothesize that ex vivo limb perfusion will enable overcoming the critical ischemic time, provide surgical opportunities such as preparation of the stump and limb, allow for spare-part surgery, enable rigorous antibiotic treatment of the limb, reduce ischemia-reperfusion injuries, enable a tissue function assessment before replantation, and enable the development of large limb transplant programs. Testing the hypothesis Data from in vivo studies in porcine models are limited by the relatively short perfusion time of 24 h. In the military setting, notably longer perfusion times need to be realized. Therefore, future animal studies must focus especially on long-term perfusion, since this represents the military setting, considering the time for stabilization of the patient until evacuation to a tertiary treatment center. Implications of the hypothesis The development and clinical introduction of ex vivo limb perfusion in the military setting could lead to a drastic reduction in the number of limb amputations among service members. Ex vivo limb perfusion enables replantation surgery in Role 4 facilities and changes the clinical setting from a highly urgent, life-threatening situation to a highly methodical, well-prepared starting point for optimal treatment of the wounded service member. With its introduction, the principle of “life before limb” will change to “life before limb before elective replantation/allotransplantation after ex vivo limb perfusion”.