Development of a 10 g/L process for a difficult-to-express multispecific antibody format using a holistic process development approach.

Ichnos has developed a multi-specific antibody platform based on the BEAT® (Bispecific engagement by antibodies based on the T-cell receptor) interface. The increased complexity of the bi- and multi-specific formats generated with this platform makes these molecules difficult-to-express proteins compared to standard monoclonal antibodies (mAbs). This report describes how expression limitations of a bi-specific bi-paratopic BEAT antibody were improved in a holistic approach. An initial investigation allowed identification of a misbalance in the subunits composing the BEAT antibody as the potential root cause. This misbalance was then addressed by a signal peptide optimization, and the overall expression level was increased by the combination of two vector design elements on a single gene vector. Further improvements were made in the selection of cell populations and an upstream (USP) platform process was applied in combination with a cell culture temperature shift. This allowed titer levels of up to 6 g/L to be reached with these difficult-to-express proteins. Furthermore, a high-density seeding process was developed that allowed titers of around 11 g/L for the BEAT antibody, increasing the initial titer by a factor of 10. The approach was successfully applied to a tri-specific antibody with titer levels reaching 10 g/L. In summary, a platform process for difficult-to-express proteins was developed using molecular biology tools, cell line development, upstream process optimization and process intensification.

Recommendations for Method Development and Validation of qPCR and dPCR Assays in Support of Cell and Gene Therapy Drug Development.

The emerging use of qPCR and dPCR in regulated bioanalysis and absence of regulatory guidance on assay validations for these platforms has resulted in discussions on lack of harmonization on assay design and appropriate acceptance criteria for these assays. Both qPCR and dPCR are extensively used to answer bioanalytical questions for novel modalities such as cell and gene therapies. Following cross-industry conversations on the lack of information and guidelines for these assays, an American Association of Pharmaceutical Scientists working group was formed to address these gaps by bringing together 37 industry experts from 24 organizations to discuss best practices to gain a better understanding in the industry and facilitate filings to health authorities. Herein, this team provides considerations on assay design, development, and validation testing for PCR assays that are used in cell and gene therapies including (1) biodistribution; (2) transgene expression; (3) viral shedding; (4) and persistence or cellular kinetics of cell therapies.

Pectoral muscle mass is not a robust prognostic factor for survival after left ventricular assist device (LVAD) implantation.

BACKGROUND: Left ventricular assist devices (LVAD) are an established treatment for end-stage left ventricular heart failure. Parameters are needed to identify the most appropriate patients for LVADs. This study aimed to evaluate pectoral muscle mass and density as prognostic parameters. METHODS: This single-center study included all patients with LVAD implantation between January 2010 and October 2017 and a preoperative chest CT scan. Pectoral muscle mass was assessed using the Pectoralis Muscle Index (PMI, surface area indexed to height, cm2/m2) and pectoral muscle density by Hounsfield Units (HU). Overall mortality was analyzed with Kaplan-Meier survival analysis and 1-year and 3-year mortality with receiver operating characteristic (ROC) curves and Cox regression models. RESULTS: 57 patients (89.5% male, mean age 57.8 years) were included. 64.9% of patients had end-stage left ventricular failure due to ischemic heart disease and 35.1% due to dilated cardiomyopathy. 49.2% of patients had preoperative INTERMACS profile of 1 or 2 and 33.3% received mechanical circulatory support prior to LVAD implantation. Total mean PMI was 4.7 cm2/m2 (± 1.6), overall HU of the major pectoral muscle was 39.0 (± 14.9) and of the minor pectoral muscle 37.1 (± 16.6). Mean follow-up was 2.8 years (± 0.2). Mortality rates were 37.5% at 1 year and 48.0% at 3 years. Neither PMI nor HU were significantly associated with overall mortality at 1-year or 3-year. CONCLUSIONS: The results of our study do not confirm the association between higher pectoral muscle mass and better survival after LVAD implantation previously described in the literature.

A successful cardiac transplant in a patient with situs inversus totalis and congenitally corrected transposition of the great arteries.

A heart transplant is the gold standard therapy for patients with end-stage heart failure. In this case report, situs inversus totalis and congenitally corrected transposition of the great arteries led to a unique and complex preoperative setting. Extended donor organ harvesting, donor graft rotation of 45° to the right and post-operative stenting of the superior vena cava were essential steps in the interdisciplinary management of this case. The patient was transferred to the intensive care unit with moderate inotropic support. He was discharged to rehabilitation on postoperative day 89 and eventually underwent an additional renal transplant 14 months after the cardiac transplant.

Impact of Impella Support on Clinical Outcomes in Patients with Postcardiotomy Cardiogenic Shock.

PURPOSE: This study aimed to elucidate the strategy of an effective Impella support for better clinical outcomes in patients with a postcardiotomy cardiogenic shock (PCCS). METHODS: This single-center retrospective observational study enrolled 31 patients with PCCS undergoing an elective open-heart surgery followed by Impella support between November 2018 and February 2022 for further analysis. RESULTS: The preoperative Euroscore II and left ventricular (LV) ejection fraction were 9.1 ± 10.4 and 35.7% ± 12.6%, respectively. The in-hospital mortality rate was 51.6% (n = 16). In survivors (n = 15), the mean Impella support time was 6.9 ± 3.5 days. Patients were discharged on the postoperative day 24.9 ± 16.4. Regarding LV remodeling, LV end-diastolic diameter was significantly decreased after Impella support (59.2 ± 6.0 mm vs. 54.4 ± 4.7 mm, p = 0.01, preoperative vs. postoperative). In-hospital mortality rates were comparable with small (CP, n = 6) or large (5.0, n = 25) Impella systems (33.3% [n = 2] vs. 56.0% [n = 14], p = 0.39). However, a lower in-hospital mortality rate was observed in the group with early initiation (i.e., intraoperative) of Impella support (n = 14) than that with delayed Impella initiation (i.e., in the postoperative course) (n = 11) (28.6% [n = 4] vs. 90.9% [n = 10], p = 0.004). CONCLUSIONS: Impella support contributes to LV remodeling in PCCS patients. In-hospital mortality was comparable in different Impella sizes and lower in early Impella initiation.

Evaluation of risk factors for cytomegalovirus DNAemia after end of regular prophylaxis after heart transplantation.

BACKGROUND: Cytomegalovirus (CMV) infections after heart transplantation (HTx) can cause cardiac allograft vasculopathy. Consequently, monitoring and prophylaxis for cytomegalovirus deoxyribonucleic acid (CMV-DNAemia) within the first weeks after HTx is recommended. METHODS: All patients who underwent HTx between September 2010 and 2021 surviving the first 90 days (n = 196) were retrospectively reviewed. The patients were divided on the prevalence of CMV-DNAemia during the first postoperative year after the end of the prophylaxis. A total of n = 35 (20.1%) developed CMV-DNAemia (CMV group) and were compared to patients without CMV-DNAemia (controls, n = 139). The remaining patients (n = 22) were excluded due to incomplete data. RESULTS: Positive donors and negative recipients (D+/R-) and negative donors and positive recipients (D-/R+) serology was significantly increased and D-/R- decreased in the CMV group (p < .01). Furthermore, the mean age was 57.7 ± 8.7 years but only 53.6 ± 10.0 years for controls (p = .03). Additionally, the intensive care unit (p = .02) and total hospital stay (p = .03) after HTx were approximately 50% longer. Interestingly, the incidence of CMV-DNAemia during prophylaxis was only numerically increased in the CMV group (5.7%, respectively, 0.7%, p = .10), the same effect was also observed for postoperative infections. Multivariate analyses confirmed that D+/R- and D-/R+ CMV immunoglobulin G match were independent risk factors for postprophylaxis CMV-DNAemia. CONCLUSION: Our data should raise awareness of CMV-DNAemia after the termination of regular prophylaxis, as this affects one in five HTx patients. Especially old recipients as well as D+/R- and D-/R+ serology share an elevated risk of late CMV-DNAemia. For these patients, prolongation, or repetition of CMV prophylaxis, including antiviral drugs and CMV immunoglobulins, may be considered.

Synchronous Donor Heart and Lung Procurement Does Not Impair Outcomes After Heart Transplant.

OBJECTIVES: Donor hearts frequently originate from donors whose lungs are also recovered for transplant. Synchronous heart and lung procurement is more complex than procurement ofthe heart alone, and the effects on outcomes are debated. This study examines the effect of synchronous procurement on outcomes in heart transplant recipients. MATERIALS AND METHODS: This single-center study included patients who received a heart transplant from September 2010 to June 2022. Main outcomes were overall mortality and mortality at 30 days, 3 months, 1 year, and 3 years and morbidity within the first year. We analyzed overall mortality using KaplanMeier survival analysis. Logistic regression was used for the remaining outcomes, adjusting for covariates. P < .05 was considered significant. RESULTS: Our study included 253 heart transplant recipients (72.3% male, mean age 55.0 years), of which 184 patients (72.7%) received hearts from donors of heart and lung, and 69 (27.3%) received hearts from donors of only hearts. Heart-and-lung donors were younger than heart-only donors (43.2 vs 47.2 years; P = .017). Transplant recipient baseline characteristics were not different between the 2 groups. Receipt of hearts from heart-and-lung donors was not associated with higher overall mortality (P = .33) or mortality at 3 months (P = .199), 1 year (P = .348), or 3 years (P = .375), and even showed better 30-day survival than receipt of hearts from heart-only donors (p=0.035). Recipients of hearts from heart-and-lung donors did not have higher rates of postoperative mechanical circulatory support, resternotomy, or pacemaker implantation within the first year. CONCLUSIONS: Our study confirms that synchronous heart and lung procurement for transplant is not associated with worse outcomes in heart transplant recipients and that hearts originating from heart-andlung donors may even be associated with improved outcomes.

Clinical outcomes of hundred large Impella implantations in cardiogenic shock patients based on individual clinical scenarios.

BACKGROUND: Large Impella systems (5.0 or 5.5; i.e., Impella 5+) (Abiomed Inc., Danvers, MA, USA) help achieve better clinical outcomes through relevant left ventricular unloading in acute cardiogenic shock (CS). Here, we report our experience with Impella 5+, while focusing on the clinical outcomes depending on individual case scenarios in patients with acute CS. METHODS: This single-center retrospective observational study included 100 Impella 5+ implantations conducted on patients with acute CS from November 2018 to October 2021. After excluding 10 reimplantation cases, 90 cases were enrolled for further analysis. RESULTS: In-hospital and 30-day mortality rates were 56.7% (n = 51) and 48.9% (n = 44), respectively. In-hospital mortality was lower in patients with acute myocardial infarction (AMI) than in non-AMI patients (p = 0.07). Young age and low lactate levels were the independent predictors of successful transition and survival after permanent mechanical circulatory support/heart transplantation (pMCS/HTX) (age, p = 0.03; lactate level, p = 0.04; survived after pMCS/HTX, n = 11; died on Impella, n = 41). During simultaneous utilization of venoarterial extracorporeal membrane oxygenation therapy and Impella 5+, termed ECMELLA therapy, high dose of noradrenaline was a predictive factor for in-hospital mortality by multivariate analysis (n = 0.02). CONCLUSIONS: Our results suggest that enhanced Impella support might have better clinical outcomes among acute CS patients supported with large Impella, those with AMI than those with no AMI. Young age and low lactate levels were predictors of successful bridging to pMCS/HTX and favorable clinical outcomes thereafter. The clinical outcomes of ECMELLA therapy might depend on noradrenaline dose at the time of Impella 5+ implantation.

Early Postoperative Neurologic Events Are Associated With Worse Outcome and Fatal Midterm Survival After Adult Heart Transplantation.

Background Neurologic events during primary stay in heart transplant (HTx) recipients may be associated with reduced outcome and survival, which we aim to explore with the current study. Methods and Results We screened and included all patients undergoing HTx in our center between September 2010 and December 2022 (n=268) and checked for the occurrence of neurologic events within their index stay. Neurologic events were defined as ischemic stroke, hemorrhage, hypoxic ischemic injury, or acute symptomatic neurologic dysfunction without central nervous system injury. The cohort was then divided into recipients with (n=33) and without (n=235) neurologic events after HTx. Using a multivariable Cox regression model, the association of neurologic events after HTx and survival was assessed. Recipients with neurologic events displayed a longer intensive care unit stay (30 versus 16 days; P=0.009), longer mechanical ventilation (192 versus 48 hours; P<0.001), and higher need for blood transfusion, and need for hemodialysis after HTx was substantially higher (81% versus 55%; P=0.01). Resternotomy (36% versus 26%; P=0.05) and mechanical life support (extracorporeal life support) after HTx (46% versus 24%; P=0.02) were also significantly higher in patients with neurologic events. Covariable-adjusted multivariable Cox regression analysis revealed a significant independent association of neurologic events and increased 30-day (hazard ratio [HR], 2.5 [95% CI, 1.0-6.0]; P=0.049), 1-year (HR, 2.2 [95% CI, 1.1-4.3]; P=0.019), and overall (HR, 2.5 [95% CI, 1.5-4.2]; P<0.001) mortality after HTx and reduced Kaplan-Meier survival up to 5 years after HTx (P<0.001). Conclusions Neurologic events after HTx were strongly and independently associated with worse postoperative outcome and reduced survival up to 5 years after HTx.

Three-Dimensional Bioprinting of Ovine Aortic Valve Endothelial and Interstitial Cells for the Development of Multicellular Tissue Engineered Tissue Constructs.

To investigate the pathogenic mechanisms of calcified aortic valve disease (CAVD), it is necessary to develop a new three-dimensional model that contains valvular interstitial cells (VIC) and valvular endothelial cells (VEC). For this purpose, ovine aortic valves were processed to isolate VIC and VEC that were dissolved in an alginate/gelatin hydrogel. A 3D-bioprinter (3D-Bioplotter® Developer Series, EnvisionTec, Gladbeck, Germany) was used to print cell-laden tissue constructs containing VIC and VEC which were cultured for up to 21 days. The 3D-architecture, the composition of the culture medium, and the hydrogels were modified, and cell viability was assessed. The composition of the culture medium directly affected the cell viability of the multicellular tissue constructs. Co-culture of VIC and VEC with a mixture of 70% valvular interstitial cell and 30% valvular endothelial cell medium components reached the cell viability best tested with about 60% more living cells compared to pure valvular interstitial cell medium (p = 0.02). The tissue constructs retained comparable cell viability after 21 days (p = 0.90) with different 3D-architectures, including a "sandwich" and a "tube" design. Good long-term cell viability was confirmed even for thick multilayer multicellular tissue constructs. The 3D-bioprinting of multicellular tissue constructs with VEC and VIC is a successful new technique to design tissue constructs that mimic the structure of the native aortic valve for research applications of aortic valve pathologies.

Reply to Thet et al. Comment on "Oehler et al. Outcome and Midterm Survival after Heart Transplantation Is Independent from Donor Length of Stay in the Intensive Care Unit. Life 2022, 12, 1053".

Myat Soe Thet et al. published a letter [...].

Changes in Therapy and Outcome of Patients Requiring Veno-Venous Extracorporeal Membrane Oxygenation for COVID-19.

BACKGROUND: Coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome requiring veno-venous extracorporeal membrane oxygenation (vv-ECMO) is related with poor outcome, especially in Germany. We aimed to analyze whether changes in vv-ECMO therapy during the pandemic were observed and lead to changes in the outcome of vv-ECMO patients. METHODS: All patients undergoing vv-ECMO support for COVID-19 between 2020 and 2021 in a single center (n = 75) were retrospectively analyzed. Weaning from vv-ECMO and in-hospital mortality were defined as primary and peri-interventional adverse events as secondary endpoints of the study. RESULTS: During the study period, four infective waves were observed in Germany. Patients were assigned correspondingly to four study groups: ECMO implantation between March 2020 and September 2020: first wave (n = 11); October 2020 to February 2021: second wave (n = 23); March 2021 to July 2021: third wave (n = 25); and August 2021 to December 2021: fourth wave (n = 20). Preferred cannulation technique changed within the second wave from femoro-femoral to femoro-jugular access (p < 0.01) and awake ECMO was implemented. Mean ECMO run time increased by more than 300% from 10.9 ± 9.6 (first wave) to 44.9 ± 47.0 days (fourth wave). Weaning of patients was achieved in less than 20% in the first wave but increased to approximately 40% since the second one. Furthermore, we observed a continuous numerically decrease of in-hospital mortality from 81.8 to 57.9% (p = 0.61). CONCLUSION: Preference for femoro-jugular cannulation and awake ECMO combined with preexisting expertise and patient selection are considered to be associated with increased duration of ECMO support and numerically improved ECMO weaning and in-hospital mortality.

Transplantation of hearts from SARS-CoV-2 positive donors.

Incidence of SARS-CoV-2 remains high in the population. Consequently, an increasing percentage of reported organ donors are also SARS-CoV-2 positive. Although donors may not have experienced COVID-19-related symptoms, there is a chance of unnoticed cardiovascular effects associated with this disease. Therefore, SARS-CoV-2 donor grafts have been regularly rejected for heart transplantation (HTx) for a long time. We hereby present three consecutive patients receiving grafts from SARS-CoV-2 positive donors (defined by the PCR cycle threshold value < 30). All patients underwent HTx after a previous triple mRNA vaccination (mRNA-BNT162b2 vaccine, Comirnaty) without adverse events and with a regular post-operative course. Cardiovascular magnetic resonance and endomyocardial biopsies confirmed excellent graft function without signs of rejection or viral myocarditis. After a mean follow-up of 135 days after HTx, all patients were in good conditions without heart failure, viral myocarditis, or SARS-CoV-2 infection. Thus, we conclude that HTx with SARS-CoV-2 positive donors seems safe and feasible.

Impact of circadian rhythm and daytime variation on outcome after heart transplantation.

INTRO: Recently, the impact of circadian rhythm and daytime variation on surgical outcomes has attracted interest. Although studies for coronary artery and aortic valve surgery report contrary results, effects on heart transplantation have not been studied. METHODS: Between 2010 and February 2022, 235 patients underwent HTx in our department. The recipients were reviewed and categorized according to the start of the HTx procedure - between 04:00 am and 11:59 am (morning, n = 79), 12:00 pm and 07:59 pm (afternoon, n = 68) or 08:00 pm and 03:59 am (night, n = 88). RESULTS: The incidence of high urgency status was slightly but not significantly increased (p = .08) in the morning (55.7%), compared to the afternoon (41.2%) or night (39.8%). The most important donor and recipient characteristics were comparable among the three groups. The incidence of severe primary graft dysfunction (PGD) requiring extracorporeal life support (morning: 36.7%, afternoon: 27.3%, night: 23.0%, p = .15) was also similarly distributed. In addition, there were no significant differences for kidney failure, infections, and acute graft rejection. However, the incidence of bleeding that required rethoracotomy showed an increased trend in the afternoon (morning: 29.1%, afternoon: 40.9%, night: 23.0%, p = .06). 30-day survival (morning: 88.6%, afternoon: 90.8%, night: 92.0%, p = .82) and 1-year survival (morning: 77.5%, afternoon: 76.0%, night: 84.4%, p = .41) were comparable between all groups. CONCLUSION: Circadian rhythm and daytime variation did not affect the outcome after HTx. Postoperative adverse events as well as survival were comparable throughout day- and night-time. As the timing of the HTx procedure is rarely possible and depends on the timing of organ recovery, these results are encouraging, as they allow for the continuation of the prevalent practice.

Combining aortic arch dissection stent implantation and root surgery for aortic dissection type A.

BACKGROUND: Acute aortic dissection type A (AADA) is associated with high perioperative morbidity and mortality. A novel non-covered hybrid prosthesis (AMDS, CryoLife, Kennesaw, USA) can be easily implanted to stabilize the true lumen. However, the role of AMDS for patients requiring additional aortic root surgery has not been described. METHODS: Between 2010 and 2020 a total of n = 370 patients underwent surgery for AADA in our department. Of those, n = 120 underwent treatment for aortic root in addition to proximal arch replacement without resection of the aorta beyond the innominate artery (Control, n = 111) and were compared to patients who received additional AMDS implantation (AMDS, n = 9). RESULTS: Aortic valve repair was performed in 48.6% (Control) and in 55.6% of AMDS patients. Cardiopulmonary bypass (Control: 248 ± 76 min, AMDS: 313 ± 53 min, P < 0.01) time as well as circulatory arrest time of the lower body (Control: 30 ± 15 min, AMDS: 52 ± 12 min, P < 0.01) was prolonged in the AMDS group. Nevertheless, postoperative in-hospital morbidity such as dialysis (Control: 22.4%, AMDS: 11.1%, P = 0.68) and stroke (Control: 17.0%, AMDS: 22.2%, P = 0.65) were comparable. In-hospital death (Control: 21.8%, AMDS: 11.1%, P = 0.68) and the compound end-point MACCE (Control: 38.7%, AMDS: 44.4%, P = 0.74) did also not differ. CONCLUSIONS: Addressing the arch by implantation of AMDS prolongs cardiopulmonary bypass and circulatory arrest time, however without relevant impairments of short-term outcome. Combining root surgery with replacement of the proximal aortic arch and AMDS implantation seems feasible and safe as it did not impair the early postoperative outcome.

Percutaneous Cannulation of Femoral Vessels in Minimally Invasive Cardiac Surgery.

OBJECTIVE: Despite the recent trend of access miniaturization in minimally invasive cardiac surgery (MICS) surgical "cut down (CD)" for femoral cannulation remains the standard at many centers. Percutaneous vascular closure (PVC) devices have recently been introduced for minimizing invasiveness during interventional diagnostic and therapy. This report summarizes the initial experience with this new approach in the setting of MICS, with a special focus on safety and advantages. METHODS: Percutaneous cannulation with a standard protocol including preoperative computer tomography imaging and intraoperative point-of-care ultrasound guidance was performed in 93 consecutive patients from September 2018 until February 2020, while conventional "CD" procedure performed in 218 patients in the previous period. We analyzed patients' characteristics and compared access site complications of PVC group versus conventional "CD" group. RESULTS: As far as operative/postoperative outcome, the duration of intensive care unit stay as well as hospital stay was statistically shorter in PVC compared with CD (CD vs. PVC: 2.74 ± 3.83 vs. 2.16 ± 2.01 days, p < 0.01, 16.7 ± 8.75 vs. 13.0 ± 4.96 days, p < 0.001, respectively). Further, we found no femoral infection or lymphocele in the PVC group, whereas 4 cases of wound complications were observed in the CD group. CONCLUSION: According to our results, percutaneous closure system for femoral vessels in MICS seems to be beneficial with the assist of preoperative computed tomography and intraoperative Doppler guidance.

Heart transplantation in the era of corona virus disease 2019: Impact of the pandemic on donors, recipients and outcome.

INTRODUCTION: Since March 2020, the COVID-19 pandemic has tremendously impacted health care all around the globe. We analyzed the impact of the pandemic on donors, recipients, and outcome of heart transplantation (HTx). METHODS: Between 2010 and early 2022, a total of n = 235 patients underwent HTx in our department. Patients were assigned to the study groups regarding the date of the performed HTx. Group 1 (09/2010 to 02/2020): n = 160, Group 2 (03/2020 to 02/2022): n = 75. RESULTS: Since the pandemic, the etiology of heart failure in the recipients has shifted from dilated (Group 1: 53.8%, Group 2: 32.0%) to ischemic cardiomyopathy (Group 1: 39.4%, Group 2: 50.7%, p < .01). The percentage of high urgency status of the recipients dropped from 50.0% to 36.0% (p = .05), and the use of left ventricular assist (LVAD) support from 56.9% to just 37.3% (p < .01). Meanwhile, the waiting time for the recipients also decreased by about 40% (p = .05). Since the pandemic, donors were 2- times more likely to have been previously resuscitated (Group 1: 21.3%, Group 2: 45.3% (p < .01), and drug abuse increased by more than 3-times (p < .01), indicating acceptance of more marginal donors. Surprisingly, the incidence of postoperative severe primary graft dysfunction requiring extracorporeal life support decreased from 33.1% to 19.4% (p = .04) since the pandemic. CONCLUSION: The COVID-19 pandemic affected both donors and recipients of HTX but not the postoperative outcome. Donors nowadays are more likely to suffer from ischemic heart disease and are less likely to be on the high-urgency waitlist and on LVAD support. Simultaneously, an increasing number of marginal donors are accepted, leading to shorter waiting times.

Donor Noradrenaline Support Is Not Associated with Decreased Survival in Heart Transplant Recipients.

Objective: Although the application of higher doses of norepinephrine (NE) in potential organ donors is a frequent reason for heart decline, its associations with outcomes after heart transplantation (HTx) are discussed controversially. Therefore, we aimed to explore donor NE support's potential impact on outcomes in our single-center heart transplant cohort. Methods: All patients who had undergone HTx in our center between September 2010 and April 2022 (n = 241) were screened for eligibility. From those, all patients with complete data on donor NE support (n = 238) were included. Recipients were divided into three groups according to their donor NE support: without support (n = 26), with low support of 0.01−0.2 µg/kg/min (n = 132), and with high support of > 0.2 µg/kg/min (n = 80). Receiver operating characteristics (ROC) and Kaplan Meier analysis was used to investigate the association of donor NE support and mortality after heart transplantation. Recipient and donor variables, including peri- and postoperative characteristics, were reviewed and compared. Results: NE support in donors ranged between 0 and 2.94 µg/kg/min (median 0.13 µg/kg/min, IQR 0.05−0.26 µg/kg/min). No association between donor NE support and mortality after HTx was observed (AUC for overall survival 0.494). Neither Kaplan-Meier analysis in survival up to 5 years after transplantation (Log Rank p = 0.284) nor group comparisons showed significant differences between the groups. With few exceptions, baseline characteristics in recipients and donors were comparable between the groups. Regarding peri- and postoperative parameters, increasing donor NE support was associated with a longer duration of mechanical ventilation (68 h and 95 h vs. 47 h), longer postoperative IMC/ICU stay (14 vs. 15 vs. 19 days), and a higher need for mechanical life support post-HTx (26% and 39% vs. 12%). Conclusion: In this retrospective analysis, NE support in donors prior to heart transplantation was unrelated to differing survival after heart transplantation. However, higher doses of donor NE were associated with prolonged ventilation, longer duration on IMC/ICU, and a higher need for extracorporeal life support in recipients post-HTx.

Preoperative atrial fibrillation predicts worse outcomes after LVAD implantation.

Introduction: Left ventricular assist device (LVAD) implantation is a common therapy for end-stage heart failure. Heart failure patients often present with atrial fibrillation (AF). The purpose of this study was to evaluate the influence of preoperative AF as well as vascular complications on outcome in LVAD patients. Methods: Between 01/2010 and 12/2017, 168 patients (141 male) with end-stage heart failure underwent LVAD implantation at a single center. Patient outcome was retrospectively studied by using the Kaplan-Meier method for analyzing crude survival as well as Cox regression for analyzing risk factors. Results: Sixty-two patients suffered from preoperative atrial fibrillation at LVAD implantation. Mean age was 56.8±11.9 years (range: 22-79) and 141 (84%) were male. Postoperative vascular or visceral surgical management due to malperfusion was needed in 27 patients (16.1%) and did not correlate with postoperative mortality (P=0.121, HR=1.587, CI=0.885-2.845). Patients with preoperative AF had a worse outcome in the Kaplan-Meier analysis (P=0.069). In contrast, cox regression showed that postoperative AF could not to be considered to be an independent predictor of mortality in this study group. Conclusion: Our data suggest that preoperative AF may be a potential predictor of mortality and impaired long-term outcome in LVAD patients. In contrast, preoperative ECLS and vascular or visceral surgery after LVAD implantation did not represent limiting factors with regard to mortality after LVAD implantation.

3D-bioprinting of aortic valve interstitial cells: impact of hydrogel and printing parameters on cell viability.

Calcific aortic valve disease (CAVD) is a frequent cardiac pathology in the aging society. Although valvular interstitial cells (VICs) seem to play a crucial role, mechanisms of CAVD are not fully understood. Development of tissue-engineered cellular models by 3D-bioprinting may help to further investigate underlying mechanisms of CAVD. VIC were isolated from ovine aortic valves and cultured in Dulbecco's modified Eagle's Medium (DMEM). VIC of passages six to ten were dissolved in a hydrogel consisting of 2% alginate and 8% gelatin with a concentration of 2 × 106VIC ml-1. Cell-free and VIC-laden hydrogels were printed with an extrusion-based 3D-bioprinter (3D-Bioplotter®Developer Series, EnvisionTec, Gladbeck, Germany), cross-linked and incubated for up to 28 d. Accuracy and durability of scaffolds was examined by microscopy and cell viability was tested by cell counting kit-8 assay and live/dead staining. 3D-bioprinting of scaffolds was most accurate with a printing pressure ofP< 400 hPa, nozzle speed ofv< 20 mm s-1, hydrogel temperature ofTH= 37 °C and platform temperature ofTP= 5 °C in a 90° parallel line as well as in a honeycomb pattern. Dissolving the hydrogel components in DMEM increased VIC viability on day 21 by 2.5-fold compared to regular 0.5% saline-based hydrogels (p< 0.01). Examination at day 7 revealed dividing and proliferating cells. After 21 d the entire printed scaffolds were filled with proliferating cells. Live/dead cell viability/cytotoxicity staining confirmed beneficial effects of DMEM-based cell-laden VIC hydrogel scaffolds even 28 d after printing. By using low pressure printing methods, we were able to successfully culture cell-laden 3D-bioprinted VIC scaffolds for up to 28 d. Using DMEM-based hydrogels can significantly improve the long-term cell viability and overcome printing-related cell damage. Therefore, future applications 3D-bioprinting of VIC might enable the development of novel tissue engineered cellular 3D-models to examine mechanisms involved in initiation and progression of CAVD.