A Multi-Center International Analysis of Lung Transplantation Outcomes in Patients With COVID-19.

INTRODUCTION: Lung transplantation has become increasingly utilized in patients with COVID-19. While several single-center and UNOS database studies have been published on lung transplants (LTs) for end-stage lung disease (ESLD) from Coronavirus disease 2019 (COVID-19), there is a lack of multi-center and international data. METHODS: This is a multicenter analysis from 11 high-volume lung transplant centers in the United States and Europe. Data were collected through the Multi-Institutional ECLS Registry and stratified by ESLD due to COVID-19 versus other etiologies. Demographics and clinical variables were compared using Chi-square test and Fisher's exact test. Survival was assessed by Kaplan-Meier curves and compared by log-rank test with propensity score matching. RESULTS: Of 1606 lung transplant recipients, 46 (2.9%) were transplanted for ESLD from COVID-19 compared to 1560 (97.1%) without a history of COVID-19. Among COVID-19 patients, 30 (65.2%) had COVID-19-associated ARDS and 16 (34.8%) had post-COVID-19 fibrosis. COVID-19 patients had higher lung allocation scores (78.0 vs. 44.4, p < 0.0001), had severely limited functional status (37.0% vs. 2.9%, p < 0.0001), had higher preoperative ECMO usage (65.2% vs. 5.4%, p < 0.0001), and spent less time on the waitlist (32 vs. 137 days, p < 0.0001). A 30-day survival was comparable between COVID-19 and non-COVID-19 patients before (100% vs. 98.7%, p = 0.39) and after propensity matching (p = 0.15). CONCLUSIONS: Patients who received LTs due to COVID-19 had short-term survival comparable to that of patients without COVID-19. Our findings support the idea that lung transplantation should be considered for select patients with ESLD due to COVID-19.

Sutureless Aortic Valve Replacement with Perceval Bioprosthesis Superior to Transcatheter Aortic Valve Implantation: A Promising Option for the Gray-Zone of Aortic Valve Replacement Procedures-A State-of-the-Art Systematic Review, Meta-Analysis, and Future Directions.

Background: The management of patients with aortic valve pathologies can sometimes fall into a "gray zone", where the optimal treatment approach is not straightforward. The comparative benefits of sutureless aortic valve replacement (SUAVR) using the Perceval bioprosthesis versus transcatheter aortic valve implantation (TAVI) for the "gray zone" of aortic valve replacement procedures remain a topic of debate. To further explore this issue, we conducted a study with pairwise, single-arm, and Kaplan-Meier-based meta-analyses to compare the outcomes of SUAVR with the Perceval bioprosthesis versus TAVI, as well as to evaluate the efficacy, safety, and durability of SUAVR with the Perceval bioprosthesis over mid-term and long-term follow-up periods. Methods: The PubMed, PubMed Central, OVID Medline, Cochrane Library, Embase, and Web of Science databases were systematically searched. All study types were included, except study protocols and animal studies, without time restrictions. The final search was carried out in May 2024. Results: No statistically significant differences were observed in permanent pacemaker implantation (PPI) rates between the two groups. SUAVR showed a lower incidence of new-onset myocardial infarction but was associated with higher rates of new-onset atrial fibrillation and major bleeding. TAVI had higher rates of left bundle branch block and major vascular complications. Conclusions: Our findings show that SUAVR has a lower incidence of complications and a favorable mid-term overall survival compared to TAVI. SUAVR has more advantages compared to TAVI and can be considered a valuable and promising option for the "grey zone" of aortic valve pathologies.

Minimally Invasive Surgery through Right Mini-Thoracotomy for Mitral Valve Infective Endocarditis: Contraindicated or Safely Possible?

Background: Mitral valve infective endocarditis (IE) still has a high mortality. Minimally invasive mitral valve surgery (MIMVS) is technically more challenging, especially in patients with endocarditis. Here, we compare the early postoperative outcome of patients with endocarditis and other indications for MIMVS. Methods: Two groups were formed, one consisting of patients who underwent surgery because of mitral valve endocarditis (IE group: n = 75) and the other group consisting of patients who had another indication for MIMVS (non-IE group: n = 862). Patients were observed for 30 postoperative days. Data were retrospectively reviewed and collected from January 2011 to September 2023. Results: Patients from the IE group were younger (60 vs. 68 years; p < 0.001) and had a higher preoperative history of stroke (26% vs. 6%; p < 0.001) with neurological symptoms (26% vs. 9%; p < 0.001). No difference was seen in overall surgery time (211 vs. 206 min; p = 0.71), time on cardiopulmonary bypass (137 vs. 137 min; p = 0.42) and aortic clamping time (76 vs. 78 min; p = 0.42). Concerning postoperative data, the IE group had a higher requirement of erythrocyte transfusion (2 vs. 0; p = 0.041). But no difference was seen in the need for a mitral valve redo procedure, bleeding, postoperative stroke, cerebral bleeding, new-onset dialysis, overall intubation time, sepsis, pacemaker implantation, wound healing disorders and 30-day mortality. Conclusions: Minimally invasive mitral valve surgery in patients with mitral valve endocarditis is feasible and safe. Infective endocarditis should not be considered as a contraindication for MIMVS.

Hypothermic Ventricular Fibrillation in Redo Minimally Invasive Mitral Valve Surgery: A Promising Solution for a Surgical Challenge.

Background: Minimally invasive mitral valve surgery (MIMVS) is a treatment for severe mitral valve pathologies. In redo cases, especially after coronary artery bypass grafting (CABG) surgery with patent mammary bypass grafts, establishing aortic clamping followed by antegrade cardioplegia application might be challenging. Here, we present the outcome of hypothermic ventricular fibrillation as an alternative to conventional cardioprotection. Methods: Patients who underwent MIMVS either received hypothermic ventricular fibrillation (study group, n = 48) or antegrade cardioprotection (control group, n = 840) and were observed for 30 postoperative days. Data were retrospectively analyzed and collected from January 2011 until December 2022. Results: Patients in the study group had a higher preoperative prevalence of renal insufficiency (p = 0.001), extracardiac arteriopathy (p = 0.001), insulin-dependent diabetes mellitus (p = 0.001) and chronic lung disease (p = 0.036). Furthermore, they had a longer surgery time and a lower repair rate (p < 0.001). No difference, however, was seen in postoperative incidences of stroke (p = 0.26), myocardial infarction (p = 1) and mitral valve re-operation (p = 1) as well as 30-day mortality (p = 0.1) and postoperative mitral valve insufficiency or stenosis. Conclusions: The patients who underwent redo MIMVS with hypothermic ventricular fibrillation did not have worse outcomes or more serious adverse events compared to the patients who received routine conventional cardioprotection. Therefore, the use of hypothermic ventricular fibrillation appears to be a promising cardioprotective technique in this challenging patient population requiring redo MIMVS.

Knockdown of swine leukocyte antigen expression in porcine lung transplants enables graft survival without immunosuppression.

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 ß2-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.

Implementation of Endoscopic Minimally Invasive Mitral Valve Replacement Surgery With Automated Suturing Technology.

In the evolving landscape of cardiac surgery, this article explores the potential of minimally invasive mitral valve replacement procedures as a viable alternative to conventional surgical techniques. Leveraging advancements in automated suturing devices and video endoscopy, our work aims to demonstrate that minimally invasive approaches can be applied across a broad spectrum of surgical scenarios. Herein we highlight preoperative diagnostics and operative techniques, with a focus on infra-axillary anterolateral minithoracotomy as the access point. Our technique utilizes technology from LSI SOLUTIONS® (Victor, NY, USA), including the RAM® Device for automated suturing, which has an ergonomic design and safety features. The device's capabilities are further enhanced by the SEW-EASY® Device, the RAM® RING, and the COR-KNOT MINI® Device, which streamline suture management and securement. This work outlines how these technological advancements can mitigate concerns about technical complexity and learning curves, thereby encouraging wider adoption of minimally invasive techniques. Clinical benefits may include reduced surgical trauma, quicker recovery, and cost-effectiveness, making it a compelling option in an era of aggressively promoted transcatheter interventions.

Hypoxic perfusion of pulmonary arterial vasa vasorum increases pulmonary arterial pressure.

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.

Kidney Transplantation as a Treatment Option of Chronic Renal Failure Among Lung Transplant Recipients: A Single-Center Experience.

INTRODUCTION: Chronic renal failure is one of the most common complications after solid organ transplantation. It is associated with multiple pre-, peri-, and post-transplant factors. In some patients, the available methods of conservative treatment are insufficient and kidney transplantation (KTx) is necessary. The aim of this study was to present our experience in the treatment of renal failure by KTx after lung transplantation (LTx). METHODS: Our study is a single-center retrospective review of clinical data of all 7 LTx recipients who underwent a KTx between the years 2013 and 2021. Patients' clinical condition, pulmonary function, renal function, and survival were examined. RESULTS: There were a total of 7 patients with medium age 36 years (±15). In 3 patients, the period of time from LTx to KTx was less than 3 years, and in 4 of them less than 13 years. Dialysis therapy was required in 4 patients. One patient had pre-LTx renal disease, while 6 patients had renal dysfunction related to post-transplant factors, including the use of calcineurin inhibitors. CONCLUSIONS: Renal protection is a very important aspect among LTx recipients; therefore, physicians must show a holistic and individual approach to patients and minimize exposure to nephrotoxic medication. Patients at high risk of developing chronic renal failure should be identified and, if required, renal replacement therapy should be initiated, including KTx.

Oversizing lung allografts deteriorates outcomes in patients with pulmonary fibrosis.

BACKGROUND: Lung transplantation is the only curative treatment for patients with end-stage pulmonary fibrosis. It is still under debate whether over- or undersizing of lung allografts is preferably performed regarding the postoperative outcome. We therefore analyzed our data using predicted total lung capacity to compare size mismatches. METHODS: Patient records were retrospectively reviewed. Three groups were formed, 1 including patients with a donor-recipients pTLC ratio (DRPR) of <1.0 (undersized group), the second with a DRPR of ≥1.0 and <1.1 (size-matched group), and the third group with a DRPR of ≥1.1 (oversized group). Outcomes were evaluated using chi-square test and Kruskall-Wallis test as well as Kaplan-Meier analysis, competing risk analysis, and multivariable analysis, respectively. RESULTS: Between January 2010 and May 2023, among the 1501 patients transplanted at our institution, 422 (28%) patients were included, 26 (2%) patients forming the oversized group (median DRPR: 1.14), 101 (7%) patients forming the size-matched group (median DRPR: 1.03), and 296 (20%) patients forming the undersized group (median DRPR: 0.92). Patients from the oversized group had a higher PGD grade 3 rate at 24 (p < 0.001), 48 (p < 0.001), and 72 (p = 0.039) hours after transplantation as well as a higher in-hospital mortality compared to the undersized group (p = 0.033). The long-term survival was also better in the undersized group compared to the oversized group (p = 0.011) and to the size-matched group (p = 0.01). CONCLUSIONS: Oversizing lung allografts more than 10% deteriorated early postoperative outcomes and long-term survival in patients with pulmonary fibrosis.

Risk factors, prevention, and therapy of intraluminal stent thrombosis in frozen elephant trunk prostheses-what we know so far.

Intraluminal thrombus formation (ILT) is a recently discovered and highly clinically relevant complication after frozen elephant trunk implantation in cardiovascular surgery. In this phenomenon, a thrombus forms within the lumen of the stent graft component of the frozen elephant trunk prosthesis and puts the patient at risk for downstream embolization with visceral or lower limb ischemia. Incidence of ILT reported in the currently available studies ranges from 6% to 17% of patients after frozen elephant trunk implantation. Adverse thromboembolic events include acute occlusion of the celiac and superior mesenteric arteries, both renal arteries as well as acute lower limb ischemia due to iliac or femoral artery embolization that not infrequently require interventional or open embolectomy. Therefore, the presence of ILT is associated with increased short-term mortality and morbidity. Currently proposed strategies to avoid ILT formation include a more aggressive anticoagulation management, minimization of postoperative coagulation factor application, and even technical optimizations of the stent graft portion itself. If ILT is manifested, the therapeutic strategies tested to date are long-term escalation of anticoagulation and early endovascular extension of the FET stent graft with overstenting of the intraluminal thrombus. The long-term efficiency of these prophylactic and therapeutic measures has yet to be proven. Nonetheless, all surgeons performing the frozen elephant trunk procedure must be aware of the risk of ILT formation to facilitate a timely diagnosis and therapy.

CD14highCD16+ monocytes are the main producers of Interleukin-10 following clinical heart transplantation.

Introduction: Following heart transplantation, a cascade of immunological responses is initiated influencing the clinical outcome and long-term survival of the transplanted patients. The anti-inflammatory cytokine interleukin-10 (IL-10) was shown to be elevated in the blood of heart transplant recipients directly after transplantation but the releasing cell populations and the composition of lymphocyte subsets following transplantation have not been thoroughly studied. Methods: We identified immune cells by immunophenotyping and analyzed intracellular IL-10 production in peripheral blood mononuclear cells (PBMC) of heart transplanted patients (n= 17) before, directly after and 24h post heart transplantation. The cells were stimulated with lipopolysaccharide or PMA/Ionomycin to enhance cytokine production within leukocytes in vitro. Results and discussion: We demonstrate that intermediate monocytes (CD14highCD16+), but not CD8+ T cells, CD4+ T cells, CD56+ NK cells or CD20+ B cells appeared to be the major IL-10 producers within patients PBMC following heart transplantation. Consequently, the absolute monocyte count and the ratio of intermediate monocytes to classical monocytes (CD14+CD16-) were specifically increased in comparison to pre transplant levels. Hence, this population of monocytes, which has not been in the focus of heart transplantation so far, may be an important modulator of clinical outcome and long-term survival of heart transplant recipients. Alteration of blood-circulating monocytes towards a CD14highCD16+ phenotype could therefore shift the pro-inflammatory immune response towards induction of graft tolerance, and may pave the way for the optimization of immunosuppression.

Free heme and hemopexin in acute kidney injury after cardiopulmonary bypass and transient renal ischemia.

Free heme is released from hemoproteins during hemolysis or ischemia reperfusion injury and can be pro-inflammatory. Most studies on nephrotoxicity of hemolysis-derived proteins focus on free hemoglobin (fHb) with heme as a prosthetic group. Measurement of heme in its free, non-protein bound, form is challenging and not commonly used in clinical routine diagnostics. In contrast to fHb, the role of free heme in acute kidney injury (AKI) after cardiopulmonary bypass (CPB) surgery is unknown. Using an apo-horseradish peroxidase-based assay, we identified free heme during CPB surgery as predictor of AKI in patients undergoing cardiac valve replacement (n = 37). Free heme levels during CPB surgery correlated with depletion of hemopexin (Hx), a heme scavenger-protein. In mice, the impact of high levels of circulating free heme on the development of AKI following transient renal ischemia and the therapeutic potential of Hx were investigated. C57BL/6 mice were subjected to bilateral renal ischemia/reperfusion injury for 15 min which did not cause AKI. However, additional administration of free heme in this model promoted overt AKI with reduced renal function, increased renal inflammation, and reduced renal perfusion on functional magnetic resonance imaging. Hx treatment attenuated AKI. Free heme administration to sham operated control mice did not cause AKI. In conclusion, free heme is a predictor of AKI in CPB surgery patients and promotes AKI in transient renal ischemia. Depletion of Hx in CPB surgery patients and attenuation of AKI by Hx in the in vivo model encourage further research on Hx therapy in patients with increased free heme levels during CPB surgery.

Heart Transplantation in High-Risk Recipients Employing Donor Marginal Grafts Preserved With Ex-Vivo Perfusion.

Extending selection criteria to face donor organ shortage in heart transplantation (HTx) may increase the risk of mortality. Ex-vivo normothermic perfusion (EVP) limits ischemic time allowing assessment of graft function. We investigated the outcome of HTx in 80 high-risk recipients transplanted with marginal donor and EVP-preserved grafts, from 2016 to 2021. The recipients median age was 57 years (range, 13-75), with chronic renal failure in 61%, impaired liver function in 11% and previous cardiac surgery in 90%; 80% were mechanically supported. Median RADIAL score was 3. Mean graft ischemic time was 118 ± 25 min, "out-of-body" time 420 ± 66 min and median cardiopulmonary bypass (CPB) time 228 min (126-416). In-hospital mortality was 11% and ≥moderate primary graft dysfunction 16%. At univariable analysis, CPB time and high central venous pressure were risk factors for mortality. Actuarial survival at 1 and 3 years was 83% ± 4%, and 72% ± 7%, with a median follow-up of 16 months (range 2-43). Recipient and donor ages, pre-HTx extracorporeal life support and intra-aortic balloon pump were risk factors for late mortality. In conclusion, the use of EVP allows extension of the graft pool by recruitment of marginal donors to successfully perform HTx even in high-risk recipients.

Impact of total ischaemic time and disease severity class on graft function after bilateral lung transplantation.

OBJECTIVES: Total ischaemic time (IT) is considered a limiting factor in lung transplantation. In this retrospective study, we investigate effects of IT and disease burden on outcomes after bilateral lung transplantation. METHODS: A total of 1298 patients undergoing bilateral lung transplantation between January 2010 and May 2022 (follow-up 100%, median 54 months) were included. Pre-transplant diseases' severity (recipient body mass index, recipient age, previous lung transplantation, Tacrolimus immunosuppression, preoperative recipient extracorporeal membrane oxygenation support, lung volume reduction) for graft failure was individually calculated and-as IT-categorized. Vice versa adjusted Cox models were calculated. Considering competing risks, we assessed cumulative incidences of airway obstructive complications and chronic lung allograft dysfunction with death as competing risk factors for primary graft dysfunction were assessed by binary logistic regression. RESULTS: Higher disease burden significantly accelerated chronic lung allograft dysfunction and death occurrence (P < 0.001); IT did not. IT-adjusted disease burden strata showed 50% graft survival differences at 11 years after transplantation (range 24-74%), disease burden-adjusted IT strata 18% for all and 6% (54-60%) among those above 7 h. All significant primary graft dysfunction risk factors were diagnoses related, IT was not significantly important and odds ratios did not increase with IT. CONCLUSIONS: The eventual graft survival disadvantage that results from an IT between 7 and at least 11 h is negligible in contrast to frequent recipients' disease-based risk levels.

Lungs From Donors ≥70 Years of Age for Transplantation-Do Long-Term Outcomes Justify Their Use?

Donor shortages have led transplant centers to extend their criteria for lung donors. Accepting lung donors ≥70 years of age has previously shown good short-term outcomes; however, no mid- and long-term outcome data on these extended criteria donors has been published to date. In this study, all patients who underwent lung transplantation between 06/2010 and 12/2019 were included in the analysis, and the outcomes were compared between patients receiving organs from donors <70 years of age and patients transplanted with lungs from donors ≥70 years of age. Among the 1,168 lung-transplanted patients, 62 patients received lungs from donors ≥70 years of age. The recipient age of those receiving older organs was significantly higher, and they were more likely to suffer from obstructive lung disease. Older donors were exposed to significantly shorter periods of mechanical ventilation prior to donation, had higher Horowitz indices, and were less likely to have smoked. The postoperative time on mechanical ventilation, time on ICU, and total hospital stay were comparable. The overall survival as well as CLAD-free survival showed no differences between both groups in the follow-up period. Utilization of lungs from donors ≥70 years of age leads to excellent mid- and long-term results that are similar to organs from younger donors when the organs from older donors are carefully preselected.

Lung transplantation despite preformed donor-specific antihuman leukocyte antigen antibodies: a 9-year single-center experience.

Pretransplant allosensitization to human leukocyte antigens (HLA) increases the recipient's waiting list time and mortality in lung transplantation. Rather than waiting for crossmatch-negative donors, since 2013, recipients with preformed donor-specific antiHLA antibodies (pfDSA) have been managed with repeated IgA- and IgM-enriched intravenous immunoglobulin (IgGAM) infusions, usually in combination with plasmapheresis before IgGAM and a single dose of antiCD20 antibody. This retrospective study presents our 9-year experience with patients transplanted with pfDSA. Records of patients transplanted between February 2013 and May 2022 were reviewed. Outcomes were compared between patients with pfDSA and those without any de novo donor-specific antiHLA antibodies. The median follow-up time was 50 months. Of the 1,043 patients who had undergone lung transplantation, 758 (72.7%) did not develop any early donor-specific antiHLA antibodies, and 62 (5.9%) patients exhibited pfDSA. Among the 52 (84%) patients who completed treatment, pfDSA was cleared in 38 (73%). In pfDSA vs control patients and at 8-year follow-up, respectively, graft survival (%) was 75 vs 65 (P = .493) and freedom from chronic lung allograft dysfunction (%) was 63 vs 65 (P = .525). In lung transplantation, crossing the preformed HLA-antibody barrier is safe using a treatment protocol based on IgGAM. Patients with pfDSA have a good 8-year graft survival rate and freedom from chronic lung allograft dysfunction, similar to control patients.

Immediate major dynamic changes in the T- and NK-cell subset composition after cardiac transplantation.

Early kinetics of lymphocyte subsets involved in tolerance and rejection following heart transplantation (HTx) are barely defined. Here, we aimed to delineate the early alloimmune response immediately after HTx. Therefore, blood samples from 23 heart-transplanted patients were collected before (pre-), immediately (T0), 24 hours (T24), and 3 weeks (3 wks) after HTx. Immunophenotyping was performed using flow cytometry. A significant increase was detected for terminally differentiated (TEMRA) CD4+ or CD8+ T cells and CD56dim CD16+ NK cells immediately after HTx linked to a decrease in naïve CD8+ and CM CD4+ T as well as CD56bright CD16- NK cells, returning to baseline levels at T24. More detailed analyses revealed increased CD69+ CD25- and diminished CD69- CD25- CD4+ or CD8+ T-cell proportions at T0 associated with decreasing S1PR1 expression. Passenger T and NK cells were found at low frequencies only in several patients at T0 and did not correlate with lymphocyte alterations. Collectively, these results suggest an immediate, transient shift toward memory T and NK cells following HTx. Opposite migratory properties of naïve versus memory T and NK cells occurring in the early phase after HTx could underlie these observations and may impinge on the development of allo-specific immune responses.

Minimally Invasive Mitral Valve Surgery in the Elderly.

BACKGROUND: The minimally invasive mitral valve procedure warrants minimal surgical trauma and might influence the postoperative course positively, especially in old patients. In this retrospective study, we reviewed our experience in minimally invasive mitral valve surgery (miMVS) in patients aged ≥ 75 years. METHODS: In this retrospective cohort study, based on propensity score matching, we compared patients aged ≥75 years with patients aged <75 years who underwent miMVS. The primary endpoint was 30-day mortality. Secondary endpoints were myocardial infarction, stroke, and renal failure. RESULTS: Between January 2011 and February 2021, 761 patients underwent miMVS at our institution. After propensity score matching, a study group (≥75 years, n = 189) and a control group (<75 years, n = 189) were formed. Preoperatively patients ≥75 years more often suffered from NYHA III heart failure (60 vs. 46%; p = 0.013). Their valves were more often frequently replaced (48 vs. 32%; p < 0.001), and their postoperative ventilation time was longer (13 hours vs. 11 hours; p < 0.001). There were no statistically significant differences regarding postoperative stroke (3 vs. 0.6%; p = 0.16), myocardial infarction (0 vs. 1%; p = 0.32), renal insufficiency with new dialysis (5 vs. 4%; p = 0.62), and 30-day mortality (4 vs. 2%; p = 0.56). CONCLUSION: miMVS results in satisfactory early postoperative outcomes in elderly patients.

Does donor-recipient age mismatch have an influence on outcome after lung transplantation? A single-centre experience.

OBJECTIVES: Lack of organ donors demands transplantation of older lung allografts for recipients between 0 and 50 years. So far, it has not yet been investigated whether donor-recipient age mismatch affects long-term outcome. METHODS: Records of patients aged between 0 and 50 years were retrospectively reviewed. Donor-recipient age mismatch was calculated subtracting recipient age from donor age. Multivariable Cox regression analyses was performed to assess donor-recipient age mismatch regarding the end points' overall patient mortality, mortality conditioned to hospital discharge, biopsy-confirmed rejection and chronic lung allograft dysfunction. Furthermore, we performed competing risk analysis to analyse if age mismatch affects biopsy-confirmed rejection and CLAD while death being a competing risk. RESULTS: Between January 2010 and September 2021, out of 1363 patients who underwent lung transplantation at our institution, 409 patients fulfilled the eligibility criteria and were included. Age mismatch ranged between 0 and 56 years. Multivariable analysis revealed that donor-recipient age mismatch does not affect overall patient mortality (P = 0.19), biopsy-confirmed rejection (P = 0.68) and chronic lung allograft dysfunction (P = 0.42). There was no difference seen in CLAD (P = 0.166) and biopsy-confirmed rejection (P = 0.944) with the competing risk death (P = 0.765 and P = 0.851; respectively). CONCLUSIONS: Age mismatch between recipients and donors of lung allografts does not affect long-term outcomes after lung transplantation.

COVID-19 in pediatric lung transplant recipients: Clinical course and outcome.

BACKGROUND: COVID-19 causes high morbidity and mortality in adult lung transplant (LTX) recipients. Data on COVID-19 in children after LTX is limited. We report the clinical presentation and outcome of SARS-CoV-2 infection in 19 pediatric LTX recipients. METHODS: Between March 2020 and June 2022, SARS-CoV-2 testing was performed on all pediatric LTX patients with COVID-19 symptoms or contact with a SARS-CoV-2 infected person. Positive patients were prospectively evaluated for symptoms, treatment and outcome. Vaccination status and immune response were recorded. RESULTS: Nineteen out of 51 pediatric LTX recipients had a SARS-CoV-2 infection. Mean age was 12.3 years (IQR 9-17), 68% were female, 84% had preexisting comorbidities. Mean time between LTX and SARS-CoV-2 infection was 4.8 years (IQR 2-6). No patients experienced severe COVID-19: 11% were asymptomatic, and 89% had mild symptoms, primarily rhinitis (74%), fever (47%), and cough (37%). One SARS-CoV-2 positive patient was hospitalized due to combined fungal and bacterial infection. Mean duration of symptoms was 10.5 days (IQR 3-16), whereas mean period of positivity by antigen test was 21 days (IQR 9-27, p = 0.013). Preventive antiviral therapy was initiated in 3 patients. After a mean follow-up of 2.5 months (IQR 1.1-2.4), no patient reported persistent complaints related to COVID-19. Lung function tests remained stable. CONCLUSIONS: Unlike adult LTX recipients, children and adolescents are at low risk for severe COVID-19, even with risk factors beyond immunosuppression. Our findings cast doubt on the necessity of excessive isolation for these patients and should reassure clinicians and caregivers of LTX patients.