Structural components for the development of a heart failure network

Diagnosis and treatment of heart failure (HF) is challenging, and development of specialized HF networks is mandatory to warrant broad access to guideline directed therapies for patients. Numerous national cardiovascular societies recommend a three-level association of health care providers. This comprises tertiary academic centres, specialized HF clinics and specialized general cardiologists to cover the large spectrum of HF severity and entities. Although this idea of a multi-level care is widely accepted, optimal approach to build and implement a HF network service needs further definition. The core principle is that of network healthcare facilities that also consider regional peculiarities and that implements academic standards, quality indicators (QIs), interdisciplinarity and reimbursement strategies. These determinants of trans-sectoral healthcare need to be embedded in a network that provides sustainability and that incorporates QIs to objectify the efficacy of specific measures. The basis of a HF-network should be a certification system of the respective national HF association to warrant guideline standards and to prevent development of regional hierarchies or dependencies between members. This nationwide framework needs to be complemented by a federal system of regional networks, which also takes local demands into account. These regional units should incorporate digital communication and interaction pathways, structured educational programmes, certified telehealth concepts and follow-up algorithms to meet the requirements of sustainability and efficacy. We here summarize different components of HF networks and introduce the structure and development philosophy of the RUHR-HF-network that constitutes the first certified HF-clinics-network in the Ruhr area-the largest metropolitan area in Germany.

Removal of Apixaban during Emergency Cardiac Surgery Using Hemoadsorption with a Porous Polymer Bead Sorbent

Background: Patients on direct oral anticoagulants are at high risk of perioperative bleeding complications. We analyzed the results of intraoperative hemoadsorption (HA) in patients undergoing cardiac surgery who were also on concurrent therapy with apixaban. Methods: we included 25 consecutive patients on apixaban who underwent cardiac surgery with the use of cardio-pulmonary bypass (CPB) at three sites. The first 12 patients underwent surgery without hemoadsorption (controls), while the next 13 consecutive patients were operated with the Cytosorb® (Princeton, NJ, USA) device integrated into the CPB circuit (HA group). The primary outcome was perioperative bleeding assessed by the Bleeding Academic Research Consortium (BARC) definition and secondary outcomes included 24 h chest-tube-drainage (CTD) and need for 1-deamino-8-d-arginine-vasopressin (desmopressin (DDAVP)) administration to achieve hemostasis. Results: Preoperative mean daily dose of apixaban was higher in the HA group (8.5 ± 2.4 vs. 5.6 ± 2.2 mg, p = 0.005), while time since last apixaban dose was longer in the controls (1.3 ± 0.9 vs. 0.6 ± 1.2 days, p < 0.001). No BARC-4 bleeding events and no repeat-thoracotomies occurred in the HA group compared with 3 and 1, respectively, in the controls. Postoperative 24 h CTD volume was significantly lower in the HA group (510 ± 152 vs. 893 ± 579 mL, p = 0.03) and there was no need for DDAVP compared to controls, who received an average of 10 ± 13.6 mg (p = 0.01). Conclusions: In patients on apixaban undergoing emergent cardiac surgery, the intraoperative use of hemoadsorption was feasible and safe. Compared to patients operated on without hemoadsorption, BARC-4 bleeding complications did not occur and the need for 24 h CTD and DDAVP was significantly lower.

Complicated Massive Left Ventricular Thrombus and Surgical Treatment

Patient: Female, 74-year-old

Final Diagnosis: Thrombosis

Symptoms: Dyspnea

Medication:—

Clinical Procedure: —

Specialty: Cardiac Surgery

Antimicrobial effects of inhaled sphingosine against Pseudomonas aeruginosa in isolated ventilated and perfused pig lungs

Background

Ex-vivo lung perfusion (EVLP) is a save way to verify performance of donor lungs prior to implantation. A major problem of lung transplantation is a donor-to-recipient-transmission of bacterial cultures. Thus, a broadspectrum anti-infective treatment with sphingosine in EVLP might be a novel way to prevent such infections. Sphingosine inhalation might provide a reliable anti-infective treatment option in EVLP. Here, antimicrobial potency of inhalative sphingosine in an infection EVLP model was tested.

Methods

A 3-hour EVLP run using pig lungs was performed. Bacterial infection was initiated 1-hour before sphingosine inhalation. Biopsies were obtained 60 and 120 min after infection with Pseudomonas aeruginosa. Aliquots of broncho-alveolar lavage (BAL) before and after inhalation of sphingosine were plated and counted, tissue samples were fixed in paraformaldehyde, embedded in paraffin and sectioned. Immunostainings were performed.

Results

Sphingosine inhalation in the setting of EVLP rapidly resulted in a 6-fold decrease of P. aeruginosa CFU in the lung (p = 0.016). We did not observe any negative side effects of sphingosine.

Conclusion

Inhalation of sphingosine induced a significant decrease of Pseudomonas aeruginosa at the epithelial layer of tracheal and bronchial cells. The inhalation has no local side effects in ex-vivo perfused and ventilated pig lungs.

Lung Volume Reduction Followed by Lung Transplantation in Emphysema-A Multicenter Matched Analysis

Objective: The impact of previous lung volume reduction surgery (LVRS) or endoscopic lung volume reduction (ELVR) on lung transplantation (LuTX) remains unclear. This study assesses the risk of previous lung volume reduction on the outcome of a later LuTX.

Methods: Patients suffering from emphysema who underwent bilateral LuTX were included in this multicenter analysis. Study groups were defined as: previous LVRS, previous ELVR, controls. Imbalances were corrected by coarsened exact matching for center, gender, age, diagnosis, and BMI. A comparative analysis of intraoperative characteristics, perioperative outcome and long-term survival was performed.

Results: 615 patients were included (LVRS = 26; ELVR = 60). Compared to controls, LVRS patients had a higher rate of postoperative ECMO (15.4 vs. 3.9%; p = 0.006), whereas ELVR patients suffered more often from wound infections (8.9% vs. 2.5%; p = 0.018). Perioperative outcome, duration of ventilation, ICU stay, and hospital stay were comparable between groups. Bacterial colonization of the airway differed significantly between both LVR groups and controls in pre- and post-LuTX cultures. Survival was not impacted (1-/3-/5-year survival for LVRS: 92.3%/85.7%/77.1%; controls: 91.3%/82.4%/76.3%; p = 0.58 | ELVR: 93.1%/91%/91%; controls 91.2%/81.7%/75.3%; p = 0.17).

Conclusion: Lung volume reduction does not impact short and long-time survival after bilateral LuTX. Due to differences in airway colonization after LVR, caution to prevent infectious complications is warranted.

Early experience with the Impella pump: Single-center registry

BACKGROUND

With the rapid development of mechanical circulatory support technologies, patients presenting with cardiogenic shock have gained access to various treatment opportunities which were not until recently available. The Impella® pump (Abiomed, Danvers, USA) is a minimally invasive device which provides excellent left ventricular unloading and full circulatory support. The aim of the study was to review our center's experience with Impella® and to analyze the major adverse events associated with the device.

METHODS

From January 2020 to January 2022, a total of 32 patients underwent Impella® implantation at our center for various indications.

RESULTS

The mean age at surgery was 60.3 ± 12.4 years and 9.4% were female. All patients presented with acute cardiogenic shock in INTERMACS Class I (53.1%) and INTERMACS Class II (46.9%). Twenty-six patients (81.25%) out of the whole cohort have been mobilized on Impella® support. Seventeen patients (53.1%) have been weaned from the Impella® support and 10 patients (31.3%) have been bridged to durable LVAD. The median time on Impella® was 7 days (IQR 5.0-11.0). 30-day mortality was 37.5%, with 56.25% survival until hospital discharge. Only one patient developed vascular complications consisting of arm hypoperfusion. There were no cases of stroke on Impella® support.

CONCLUSION

The Impella® axial-flow pump seems an appropriate therapeutic option for patients with acute cardiogenic shock requiring partial or full hemodynamic support. It also provides sufficient left ventricular unloading to allow full mobilization and neurological assessment of the patients. Furthermore, Impella® offers a high rate of myocardial recovery.

Lung Transplantation for Adult Respiratory Distress Syndrome after SARS-CoV-2 Infection

Background  The majority of patients with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection present mild symptoms. However, some patients develop severe acute respiratory distress syndrome (ARDS) and subsequent irreversible lung damage despite extracorporeal membrane oxygenation, leaving lung transplantation the ultimate therapeutically option. Case Description  Here, we report a case of lung transplantation in a 31-year-old male recipient suffering from post-coronavirus disease 2019 respiratory failure with irreversible ARDS after prolonged extracorporeal membrane oxygenation therapy. Conclusion  Patient selection criteria are elucidated. One relevant mechanism for susceptibility to SARS-CoV-2 in the respiratory system, the acid sphingomyelinase/ceramide system might be altered during infection with SARS-CoV-2.

Custodiol-MP for ex vivo lung perfusion - A comparison in a porcine model of donation after circulatory determination of death

INTRODUCTION

Ex vivo lung perfusion (EVLP) is an established technique to evaluate and eventually recondition lungs prior to transplantation. Custodiol-MP (C-MP) solution is a new solution, designed for clinical machine perfusion, that has been used for kidneys. The aim of this study was to compare the effects of EVLP with Custodiol-MP on lung functional outcomes to the gold standard of EVLP with Steen Solution™.

MATERIAL AND METHODS

In a porcine EVLP model of DCDD (Donation after Circulatory Determination of Death), lungs were perfused with Steen Solution™ (SS, n = 7) or Custodiol-MP solution supplemented with 55 g/l albumin (C-MP, n = 8). Lungs were stored cold for 4 h in low potassium dextran solution and subsequently perfused ex vivo for 4 h. During EVLP pulmonary gas exchange, activities of lactate dehydrogenase (LDH) and alkaline phosphatase (AP) as well as levels of lactate in the perfusate were recorded hourly.

RESULTS

Oxygenation capacity differed significantly between groups (averaged over 4 h: SS 274 ± 178 mmHg; C-MP 284 ± 151 mmHg p = 0.025). Lactate dehydrogenase activities and lactate concentrations were significantly lower in Custodiol-MP perfused lungs.In a porcine model of DCDD with 4 h of EVLP the use of modified Custodiol-MP as perfusion solution was feasible. The use of C-MP showed at least comparable lung functional outcomes to the use of Steen SolutionTM. Furthermore C-MP perfusion resulted in significantly lower lactate dehydrogenase activity and lactate levels in the perfusate and higher oxygenation capacity.

Bioassays of Humoral Cardioprotective Factors Released by Remote Ischemic Conditioning in Patients Undergoing Coronary Artery Bypass Surgery

Remote ischemic conditioning (RIC) induces the release of circulating cardioprotective factors and attenuates myocardial ischemia/reperfusion injury. Evidence for such humoral cardioprotective factor(s) is derived from transfer with plasma (derivatives) from one individual undergoing RIC to another individual's heart, even across species. With transfer into an isolated perfused heart, only a single plasma (derivative) sample can be studied with infarct size as endpoint, and therefore the comparison of samples before and after RIC or between RIC and placebo is hampered by the inter-individual variation of infarct sizes in isolated perfused hearts. We therefore developed a preparation of cardiomyocytes from a single mouse heart, where aliquots of the same heart can undergo hypoxia/reoxygenation (H/R) with exposure to buffer, RIC, or placebo samples without or with pharmacological blockade. To validate this approach, we used plasma dialysates taken before and after RIC from patients undergoing coronary bypass grafting who had experienced protection by RIC (troponin release ↓ by 28% vs placebo). The cardiomyocyte bioassay had little variation after H/R with buffer (mean ± standard deviation; 7% ± 2% viable cells) and demonstrated preserved viability after RIC (15% ± 5% vs 6% ± 3% before). For comparison, infarct size in isolated mouse hearts after global ischemia and reperfusion was 22% ± 14% of left ventricular mass after versus 42% ± 14% before RIC. Stattic, an inhibitor of signal transducer and activator of transcription (STAT)3 protein, abrogated protection in the cardiomyocytes. We have thus established a cardiomyocyte bioassay to analyze RIC's protection which minimizes inter-individual variation and the use of animals.

Impact of severe mitral regurgitation on postoperative outcome after durable left-ventricular assist device implantation

BACKGROUND

Mitral valve regurgitation (MR) is a common finding in patients with end-stage heart failure. The aim of the study was to analyze the impact of preoperative moderate-to-severe MR on postoperative outcomes and survival after durable left-ventricular assist device (LVAD) implantation.

METHODS

From August 2010 to May 2021, 246 patients underwent a durable LVAD implantation. We stratified the patients into two groups: Group A (n = 109) presented with MR 0-I°, and Group B presented with MR II-III° (n = 137). MR II-III° was defined according to the current recommendations (i.e., vena contracta ≥ 7 mm, regurgitation volume ≥ 30 ml or effective regurgitation orifice area ≥ 20 mm² ).

RESULTS

Significantly more patients in Group B suffered from pulmonary hypertension and presented with chronic obstructive lung disease. We observed significantly higher rates of tricuspid regurgitation (TR) II-III° in Group B (76.1%) versus Group A (14.8%) (p < 0.001) and TR III° in Group B (30.4%) versus Group A (3.7%) (p < 0.001). There was no difference in the incidence of right heart failure between the groups. Within our cohort, the in-hospital, 1-year, 3-year, and 5-year mortality was 22.4%, 32.1%, 50.7%, and 64.4%, respectively. Group B showed significantly worse overall survival (p = 0.05). Patients with preoperative TR II-III° had a significantly worse survival than those with TR 0-I° (p = 0.048). In patients presenting with MR II-III°, we discovered that TR III° seems to predict both in-hospital and mid-term mortality.

CONCLUSION

MR II-III° negatively affects the outcomes in patients requiring LVAD implantation. Persisting MR II-III° is an independent predictor of mortality. Patients with concomitant preoperative TR II-III° are at increased risk of developing postoperative major adverse events. Addressing the MR might be considered for these patients.

Alternative access in high-risk patients in the era of transfemoral aortic valve replacement

BACKGROUND

We aimed to evaluate the outcomes of transapical and transaortic transcatheter aortic valve replacement (TAVR) in high-risk patients who were not suitable for transfemoral access and had a logistic EuroSCORE-I ≥ 25% and Society of Thoracic Surgeons (STS) score >6%. 'STS/ACC TAVR In-Hospital Mortality Risk App' was evaluated.

MATERIAL AND METHODS

Between January 2016 and May 2020, 126 patients at very high risk for aortic valve replacement underwent transapical (n = 121) or transaortic (n = 5) transcatheter aortic valve replacement. TAVR was performed using SAPIEN 3™ or ACURATE TA™ prosthesis.

RESULTS

The logistic EuroSCORE-I was 40.6 ± 14.0%, the STS-score 7.9 ± 4.6%, and STS/ACC-score 8.4 ± 3.4%. Valve implantation was successful in all patients. Operative, in-hospital and 30-days mortality, were 0, 7.9, and 13.5%, respectively. Survival was 72% at one year and 48% at four years. Expected/observed in-hospital mortality was 1.0 for the STS-score and 1.06 for the STS/ACC-score. Renal failure, low ejection fraction, and postoperative acute kidney injury, hemorrhage, and vascular complications were identified as independent predictors for 30-day mortality.

CONCLUSIONS

Transapical and transaortic TAVR in high-risk patients unsuitable for transfemoral access is still a reasonable alternative in these patients. STS and STS/ACC-score appear to be highly accurate in predicting in-hospital mortality in high-risk patients undergoing TAVR.

Impact of gender in patients with continuous-flow left ventricular assist device therapy in end-stage heart failure

BACKGROUND

There is an ongoing debate about the influence of the female gender on postoperative outcomes after durable left ventricular assist device (LVAD) implantation. Despite the differences in pathophysiology of heart failure in females, therapy concepts are the same as in the male population. The aim of this study was to investigate the role of the female gender in surgical heart failure therapy.

MATERIALS AND METHODS

Between August 2010 and January 2020, 207 patients were treated with durable LVAD at out institution. We matched 111 patients in two groups to compare the outcomes in male and female patients and to stratify the risk factors of mortality.

RESULTS

The groups were matched 2:1 and were comparable after matching. We found no difference in in-hospital and follow-up mortality between male and female patients. Postoperative adverse events and complications were found to be unvaried across male and female patients. Female patients had higher rates of postoperative LVAD-thrombosis compared to their male counterparts (13.5% vs 0, p = 0.001) and the rates of renal replacement therapy lasting over 90 days were also higher in the female group (33.8% vs 56.8%, p = 0.021). Furthermore, the female gender was not an independent predictor neither of in-hospital nor follow-up mortality.

CONCLUSIONS

Durable continuous flow left ventricular assist devices as a bridge to transplantation or recovery in female patients are associated with a higher risk of acute kidney injury requiring RRT and are at a higher risk of LVAD-thrombosis. Nevertheless, survival rates between genders are similar.

Transapical transcatheter mitral valve implantation in patients with degenerated mitral bioprostheses or failed ring annuloplasty

Background

We sought to evaluate the outcomes of transapical transcatheter mitral valve replacement in patients with degenerated mitral bioprostheses or failed mitral ring annuloplasty and high surgical risk for redo mitral valve procedure.

Methods

Between August 2012 and December 2020, 41 consecutive high-risk patients underwent transcatheter mitral 'valve-in-valve' (TM-ViV, n=25) or 'valve-in-ring' (TM-ViR, n=16) implantation at our institution. All procedures were performed in a hybrid operating theater using the SAPIEN XT/3™ or the DIRECT FLOW MEDICAL™ prostheses. Data was collected prospectively according to MVARC criteria.

Results

The logistic EuroSCORE-I was 42.3%±20.5% (mean ± SD), the Society of Thoracic Surgeons (STS) score was 11.9%±10.8%, and the STS/ACC-score was 7.6%±4.2%. Transcatheter mitral valve implantations were successful in all patients (100%). Early echocardiographic examinations showed no obstruction of the left ventricular outflow tract (LVOT), no paravalvular leakage, and only trace transvalvular leakage in eight patients. There was no operative mortality; thirty-day mortality was 9.8%. Survival was 72% at one year and 63% at three years. At two-year follow-up, transvalvular mean pressure gradients were 4.6±1.4 mmHg.

Conclusions

Transapical transcatheter mitral valve-in-valve or valve-in-ring implantation represents a true minimally invasive alternative to surgical redo procedures, especially in high-risk patients with failed bioprosthetic mitral valves or annuloplasty and favorable anatomy.

Initial experience with CytoSorb therapy in patients receiving left ventricular assist devices

BACKGROUND

The use of left ventricular assist devices (LVAD) in patients with advance heart failure is still associated with an important risk of immune dysregulation and infections. The aim of this study was to determine whether extracorporeal blood purification using the CytoSorb device benefits patients after LVAD implantation in terms of complications and overall survival.

MATERIALS AND METHODS

Between August 2010 and January 2020, 207 consecutive patients underwent LVAD implantation, of whom 72 underwent CytoSorb therapy and 135 did not. Overall survival, major adverse events, and laboratory parameters were compared between 112 propensity score-matched patients (CytoSorb: 72 patients; non-CytoSorb: 40 patients).

RESULTS

WBC (p = .033), CRP (p = .001), and IL-6 (p < .001), significantly increased with LVAD implantation, while CytoSorb did not influence this response. In-hospital mortality and overall survival during follow-up were similar with CytoSorb. However, patients treated with CytoSorb were more likely to develop respiratory failure (54.2% vs. 30.0%, p = .024), need mechanical ventilation for longer than 6 days post-implant (50.0% vs. 27.5%, p = .035), and require tracheostomy during hospitalization (31.9% vs. 12.5%, p = .040). No other significant differences were observed with regard to major adverse events during follow-up.

CONCLUSIONS

Overall, our results showed that CytoSorb might not convey a significant morbidity or mortality benefit for patients undergoing LVAD implantation.

Rescue extracorporeal life support as a bridge to durable left ventricular assist device

BACKGROUND

The ideal timing of a durable assist device implantation in patients with end-stage heart failure presenting with INTERMACS profile I is still controversial. The data on extracorporeal life support (ECLS) bridge to durable left ventricular assist device (LVAD) in these patients is limited.

MATERIALS AND METHODS

We retrospectively analyzed the outcomes of 35 patients in acute cardiogenic shock (CS) who, between December 2013 and September 2020, were bridged with ECLS to durable LVAD. The mean age was 52.3 ± 12.0 years. The primary endpoints of this study were in-hospital, 30-day, 6-month, and 1-year mortality. The secondary endpoint was the development of any postoperative adverse events and other characteristics during the follow-up period. We also assessed the impact of the rescue ECLS on the recovery of the end-organ function.

RESULTS

In-hospital, 30-day, 6-month, and 1-year survival was 65.6%, 75.9%, 69.2%, and 62.7% respectively. The median time on ECLS was 7 days (IQR 5.0-13.0). We observed a high incidence of a severe right heart failure (22.9%), acute kidney injury on dialysis (68.6%), and respiratory failure (77.1%). Bridge with ECLS provided a significant recovery of liver and kidney function prior to durable LVAD implantation.

CONCLUSION

The concept of bridging patients presenting in end-stage heart failure and cardiogenic shock with ECLS prior to durable LVAD implantation is a feasible method to ensure acceptable survival rates and significant recovery of the end-organ function.

Mitochondrial Telomerase Reverse Transcriptase Protects from Myocardial Ischemia/reperfusion Injury by Improving Complex I Composition and Function

Background: The catalytic subunit of telomerase, Telomerase Reverse Transcriptase (TERT) has protective functions in the cardiovascular system. TERT is not only present in the nucleus, but also in mitochondria. However, it is unclear whether nuclear or mitochondrial TERT is responsible for the observed protection and appropriate tools are missing to dissect this. Methods: We generated new mouse models containing TERT exclusively in the mitochondria (mitoTERT mice) or the nucleus (nucTERT mice) to finally distinguish between the functions of nuclear and mitochondrial TERT. Outcome after ischemia/reperfusion, mitochondrial respiration in the heart as well as cellular functions of cardiomyocytes, fibroblasts, and endothelial cells were determined. Results: All mice were phenotypically normal. While respiration was reduced in cardiac mitochondria from TERT-deficient and nucTERT mice, it was increased in mitoTERT animals. The latter also had smaller infarcts than wildtype mice, whereas nucTERT animals had larger infarcts. The decrease in ejection fraction after one, two and four weeks of reperfusion was attenuated in mitoTERT mice. Scar size was also reduced and vascularization increased. Mitochondrial TERT protected a cardiomyocyte cell line from apoptosis. Myofibroblast differentiation, which depends on complex I activity, was abrogated in TERT-deficient and nucTERT cardiac fibroblasts and completely restored in mitoTERT cells. In endothelial cells, mitochondrial TERT enhanced migratory capacity and activation of endothelial NO synthase. Mechanistically, mitochondrial TERT improved the ratio between complex I matrix arm and membrane subunits explaining the enhanced complex I activity. In human right atrial appendages, TERT was localized in mitochondria and there increased by remote ischemic preconditioning. The Telomerase activator, TA-65 evoked a similar effect in endothelial cells, thereby increasing their migratory capacity, and enhanced myofibroblast differentiation. Conclusions: Mitochondrial, but not nuclear TERT, is critical for mitochondrial respiration and during ischemia/reperfusion injury. Mitochondrial TERT improves complex I subunit composition. TERT is present in human heart mitochondria, and remote ischemic preconditioning increases its level in those organelles. TA-65 has comparable effects ex vivo and improves migratory capacity of endothelial cells and myofibroblast differentiation. We conclude that mitochondrial TERT is responsible for cardioprotection and its increase could serve as a therapeutic strategy.

Genetic inhibition of Nuclear Factor of Activated T-cell c2 (NFATc2) prevents atrial fibrillation in CREM transgenic mice

AIMS

Abnormal intracellular calcium handling contributes to the progressive nature of atrial fibrillation (AF), the most common sustained cardiac arrhythmia. Evidence in mouse models suggests that activation of the nuclear factor of activated T-cell (NFAT) signaling pathway contributes to atrial remodeling. Our aim was to determine the role of NFATc2 in AF in humans and mouse models.

METHODS AND RESULTS

Expression levels of NFATc1-c4 isoforms were assessed by quantitative reverse transcription-polymerase chain reaction in right atrial appendages from patients with chronic AF. NFATc1 and NFATc2 mRNA levels were elevated in chronic AF (cAF) patients compared with those in sinus rhythm (SR). Western blotting revealed increased cytosolic and nuclear levels of NFATc2 in AF patients. Similar findings were obtained in CREM-IbΔC-X transgenic (CREM) mice, a model of progressive AF. Telemetry ECG recordings revealed age-dependent spontaneous AF in CREM mice, which was prevented by NFATc2 knockout in CREM: NFATc2-/- mice. Programmed electrical stimulation revealed that CREM: NFATc2-/- mice lacked an AF substrate. Morphometric analysis and histology revealed increased atrial weight and atrial fibrosis in CREM mice compared with WT controls, which was reversed in CREM: NFATc2-/- mice. Confocal microscopy showed an increased Ca2+ spark frequency despite a reduced sarcoplasmic reticulum (SR) Ca2+ load in CREM mice compared with controls, whereas these abnormalities were normalized in CREM: NFATc2-/- mice. Western blotting revealed that genetic inhibition of Ca2+/calmodulin-dependent protein kinase II-mediated phosphorylation of S2814 on RyR2 in CREM: RyR2-S2814A mice suppressed NFATc2 activation observed in CREM mice, suggesting that NFATc2 is activated by excessive SR Ca2+ leak via RyR2. Finally, chromatin immunoprecipitation sequencing from AF patients identified Ras And EF-Hand Domain-Containing Protein (RASEF) as a direct target of NFATc2 mediated transcription.

CONCLUSION

Our findings reveal activation of the NFAT signaling pathway in patients of Chinese and European descent. NFATc2 knockout prevents the progression of AF in the CREM mouse model.

TRANSLATIONAL PERSPECTIVE

Atrial fibrillation (AF) is a progressive disease characterized by electrical and structural remodeling which promotes atrial arrhythmias. This study provides evidence for increased 'nuclear factor of activated T-cell' (NFAT) signaling in patients with chronic AF. Studies in the CREM transgenic model of progressive AF revealed that the NFATc2 isoform mediates atrial remodeling associated with AF substrate development. Chromatin immunoprecipitation sequencing of atrial biopsies from AF patients identified 'Ras And EF-Hand Domain-Containing Protein' (RASEF) as a downstream target of NFATc2-mediated transcription, suggesting that targeting these factors might be beneficial for curtailing AF progression.

P. aeruginosa Induced Lipid Peroxidation Causes Ferroptotic Cell Death in Airways

BACKGROUND/AIMS

Oxidative stress and infections by Pseudomonas aeruginosa (P. aeruginosa) are prominent in lungs of patients suffering from cystic fibrosis (CF).

METHODS

The present study examines effects of P. aeruginosa on lipid peroxidation in human and mouse lungs, and cell death induced by P. aeruginosa in human airway epithelial cells. The role of the Ca²⁺ activated Cl^- channel TMEM16A, the phospholipid scramblase TMEM16F, and the CFTR Cl^- channel for ferroptotic cell death is examined.

RESULTS

Lipid peroxidation was detected in human CF lungs, which correlated with bacterial infection. In vivo inoculation with P. aeruginosa or Staphylococcus aureus (S. aureus) induced lipid peroxidation in lungs of mice lacking expression of CFTR, and in lungs of wild type animals. Incubation of CFBE human airway epithelial cells with P. aeruginosa induced an increase in reactive oxygen species (ROS), causing lipid peroxidation and cell death independent of expression of wt-CFTR or F508del-CFTR. Knockdown of TMEM16A attenuated P. aeruginosa induced cell death. Antioxidants such as coenzyme Q10 and idebenone as well as the inhibitor of ferroptosis, ferrostatin-1, inhibited P. aeruginosa-induced cell death. CFBE cells expressing wtCFTR, but not F508del-CFTR, activated a basal Cl^- conductance upon exposure to P. aeruginosa, which was caused by an increase in intracellular basal Ca²⁺ concentrations and activation of Ca²⁺-dependent adenylate cyclase.

CONCLUSION

The data suggest an intrinsic pro-inflammatory phenotype in CF epithelial cells, while ferroptosis is observed in both non-CF and CF epithelial cells upon infection with P. aeruginosa. CF cells fail to activate fluid secretion in response to infection with P. aeruginosa. The use of antioxidants and inhibitors of ferroptosis is proposed as a treatment of pneumonia caused by infection with P. aeruginosa.

Impact of phosphodiesterase-5 inhibitors on right ventricular function and exercise capacity after left ventricular assist-device implantation: the PIVAD study

Background

Long-term therapy with oral phosphodiesterase-5 inhibitors (PDE5I) is frequently implemented after left ventricular assist-device (LVAD) implantation to improve hemodynamics and prevent late-onset right ventricular (RV) failure or to facilitate listing for heart transplantation in individuals with persistent pulmonary hypertension. The safety and efficacy of this appoach has not been prospectively studied. Recent analyses of the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) demonstrated improved survival for patients under long-term PDE5I after 48 months but higher incidence of early postoperative RV failure as well as a higher risk for gastrointestinal bleeding.

Purpose

To evaluate the impact of discontinuation of PDE5I in patients on LVAD support.

Methods

In this prospective, single-arm, interventional study we enrolled LVAD recipients on oral PDE5I (sildenafil or tadalafil) after at least 1 month post-implant who were clinically stable on optimal medical therapy. The patients underwent physical examination, ECG, 6-minute walking test, cardiopulmonary exercise testing, transthoracic echocardiography, LVAD interrogation, questionnaire based evaluation of quality of life and testing of serum biomarkers at baseline and 4 weeks after discontinuation of oral PDE5I therapy.

Results

From 10/2019 to 02/2021 thirty patiens were included in the study and completed the follow-up. Mean age was 54 years, 90% were male. Destination therapy was the primary treatment goal in 13% of this cohort while 87% received LVAD as a bridge to transplant. Mean dosis of tadalafil was 24.6 mg, of sildenafil 42.5 mg. At follow-up no significant changes were elicited in echocardiographic markers of RV function, peak oxygen consumption, VE/VCO2 slope, eGFR, N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration, quality of life and average flow and power readings of the device but mild increase in walking distance (Table 1). Two patients were hospitalized for non-cardiac reasons (subtherapeutic INR, driveline infection). No patient was hospitalized for cardiac decompensation.

Conclusion

Discontinuation of PDE5I was not associated with deterioration of RV function, exercise capacity and quality of life after 4 weeks. The risk/benefit profile of PDE5I in LVAD patients needs to be further investigated in context of randomized controlled trials.

Funding Acknowledgement

Type of funding sources: None. Table 1

Inhaled sphingosine has no adverse side effects in isolated ventilated and perfused pig lungs

Ex-vivo lung perfusion (EVLP) systems like XVIVO are more and more common in the setting of lung transplantation, since marginal donor-lungs can easily be subjected to a performance test or be treated with corticosteroids or antibiotics in high dose regimes. Donor lungs are frequently positive in bronchoalveolar lavage (BAL) bacterial cultures (46-89%) which leads to a donor-to-recipient transmission and after a higher risk of lung infection with reduced posttransplant outcome. We have previously shown that sphingosine very efficiently kills a variety of pathogens, including Pseudomonas aeruginosa, Staphylococcus aureus and epidermidis, Escherichia coli or Haemophilus influenzae. Thus, sphingosine could be a new treatment option with broadspectrum antiinfective potential, which may improve outcome after lung transplantation when administered prior to lung re-implantation. Here, we tested whether sphingosine has any adverse effects in the respiratory tract when applied into isolated ventilated and perfused lungs. A 4-h EVLP run using minipig lungs was performed. Functional parameters as well as perfusate measurements where obtained. Biopsies were obtained 30 min and 150 min after inhalation of sphingosine. Tissue samples were fixed in paraformaldehyde, embedded in paraffin and sectioned. Hemalaun, TUNEL as well as stainings with Cy3-coupled anti-sphingosine or anti-ceramide antibodies were implemented. We demonstrate that tube-inhalation of sphingosine into ex-vivo perfused and ventilated minipig lungs results in increased levels of sphingosine in the luminal membrane of bronchi and the trachea without morphological side effects up to very high doses of sphingosine. Sphingosine also did not affect functional lung performance. In summary, the inhalation of sphingosine results in an increase of sphingosine concentrations in the luminal plasma membrane of tracheal and bronchial epithelial cells. The inhalation has no local side effects in ex-vivo perfused and ventilated minipig lungs.

Mitral surgical redo versus transapical transcatheter mitral valve implantation

Background

Transcatheter methods have been rapidly evolving to provide an alternative less invasive therapeutic option, mainly because redo patients often present with multiple comorbidities and high operative risk. We sought to evaluate and compare our experience with transapical transcatheter mitral valve replacement (TA-TMVR) to conventional redo mitral valve replacement in patients presenting with degenerated biological mitral valve prostheses or failed valve annuloplasty.

Methods and material

Between March 2012 and November 2020, 74 consecutive high-risk patients underwent surgical redo mitral valve replacement (n = 33) or TA-TMVR (n = 41) at our institution. All patients presented with a history of a surgical mitral valve procedure. All transcatheter procedures were performed using the SAPIEN XT/3™ prostheses. Data collection was prospectively according to MVARC criteria.

Results

The mean logistic EuroSCORE-II of the whole cohort was 19.9±16.7%, and the median STS-score was 11.1±12.5%. The mean age in the SMVR group was 63.7±12.8 years and in the TMVR group 73.6±9.7 years. Patients undergoing TA-TMVR presented with significantly higher risk scores. Echocardiography at follow up showed no obstruction of the left ventricular outflow tract, no paravalvular leakage and excellent transvalvular gradients in both groups (3.9±1.2 mmHg and 4.2±0.8 mmHg in the surgical and transcatheter arm respectively). There was no difference in postoperative major adverse events between the groups with no strokes in the whole cohort. Both methods showed similar survival rates at one year and a 30-day mortality of 15.2% and 9.8% in SAVR and TMVR group, respectively. Despite using contrast dye in the transcatheter group, the rate of postoperative acute kidney failure was similar between the groups.

Conclusion

Despite several contraindications for surgery, we showed the non-inferiority of TA-TMVR compared to conventional surgical redo procedures in high-risk patients. With its excellent hemodynamic and similar survival rate, TA-TMVR offers a feasible alternative to the conventional surgical redo procedure in selected patients.

Surgical redo mitral valve replacement in high-risk patients: The real-world experience

INTRODUCTION

Redo surgical mitral valve replacement (SMVR) remains the gold standard treatment in patients with a history of mitral valve surgery presenting with recurrent mitral valve pathologies. Whilst this procedure is demanding, it is an inevitable intervention for some indications, such as infective endocarditis, thrombosis, or multivalve procedures. In this study, we aim to evaluate our institutional experience with SMVR on a real-life cohort, identifying the factors that contribute to poor surgical outcomes whilst avoiding selection bias.

METHODS

Between March 2012 and November 2020, 58 consecutive high-risk patients underwent a redo SMVR at our institution. The primary endpoints of this study were 30-day and 1-year mortality. The secondary endpoint was the development of any postoperative adverse events. We analyzed and compared the survival in patients undergoing an isolated SMVR and in those that required at least one concomitant procedure.

RESULTS

The overall operative, 30-day, and 1-year mortality were 3.4%, 22.4%, and 25.9%, respectively. The mortality in patients undergoing isolated SMVR was significantly lower than in patients requiring concomitant procedures. The multivariable regression model showed that NYHA Class IV, infective endocarditis, and postoperative dialysis were significantly associated with 30-day mortality. Society of Thoracic Surgeons Score, infective endocarditis, concomitant procedures, and mechanical valve implantation appeared to predict long-term mortality.

CONCLUSION

This study illustrates that SMVR after prior mitral valve surgery presents a demanding procedure with high operative risk, significant mortality, and morbidity. Whilst this procedure is inevitable for some indications, a careful patient selection and risk stratification provides acceptable surgical results in this cohort.

NLRP3 inflammasome is a key driver of obesity-induced atrial arrhythmias

AIMS

Obesity, an established risk factor of atrial fibrillation (AF), is frequently associated with enhanced inflammatory response. However, whether inflammatory signaling is causally linked to AF pathogenesis in obesity remains elusive. We recently demonstrated that the constitutive activation of the 'NACHT, LRR, and PYD Domains-containing Protein 3' (NLRP3) inflammasome promotes AF susceptibility. In this study, we hypothesized that the NLRP3 inflammasome is a key driver of obesity-induced AF.

METHODS AND RESULTS

Western blotting was performed to determine the level of NLRP3 inflammasome activation in atrial tissues of obese patients, sheep, and diet-induced obese (DIO) mice. The increased body weight in patients, sheep, and mice was associated with enhanced NLRP3-inflammasome activation. To determine whether NLRP3 contributes to the obesity-induced atrial arrhythmogenesis, wild-type (WT) and NLRP3 homozygous knockout (NLRP3-/-) mice were subjected to high-fat-diet (HFD) or normal chow (NC) for 10 weeks. Relative to NC-fed WT mice, HFD-fed WT mice were more susceptible to pacing-induced AF with longer AF duration. In contrast, HFD-fed NLRP3-/- mice were resistant to pacing-induced AF. Optical mapping in DIO mice revealed an arrhythmogenic substrate characterized by abbreviated refractoriness and action potential duration (APD), two key determinants of reentry-promoting electrical remodeling. Upregulation of ultra-rapid delayed-rectifier K+-channel (Kv1.5) contributed to the shortening of atrial refractoriness. Increased profibrotic signaling and fibrosis along with abnormal Ca2+ release from sarcoplasmic reticulum (SR) accompanied atrial arrhythmogenesis in DIO mice. Conversely, genetic ablation of Nlrp3 (NLRP3-/-) in HFD-fed mice prevented the increases in Kv1.5 and the evolution of electrical remodeling, the upregulation of profibrotic genes, and abnormal SR Ca2+ release in DIO mice.

CONCLUSION

These results demonstrate that the atrial NLRP3 inflammasome is a key driver of obesity-induced atrial arrhythmogenesis and establishes a mechanistic link between obesity-induced AF and NLRP3-inflammasome activation.