De Ritis Ratio to Predict Clinical Outcomes of Intermediate- and High-Risk Pulmonary Embolisms

Background: Abnormal liver function tests can identify severe cardiopulmonary failure. The aspartate transaminase/alanine transaminase (AST/ALT) ratio, or the De Ritis ratio, is commonly used to evaluate acute liver damage. However, its prognostic value in pulmonary embolism (PE) is unknown. Methods: Two cohorts, including patients with intermediate- and high-risk PEs, were established: one with an abnormal baseline AST/ALT ratio (>1) and another with a normal baseline AST/ALT ratio (<1). The primary outcome was a 60-day mortality. Secondary outcomes included peak N-terminal pro-brain-natriuretic-peptide (NT-proBNP) levels, complications, and the need for critical care treatment. To assess the effect of abnormal AST/ALT ratios, inverse probability weighted (IPW) analyses were performed. Results: In total, 230 patients were included in the analysis, and 52 (23%) had an abnormal AST/ALT ratio. After the IPW correction, patients with an abnormal AST/ALT ratio had a significantly higher mortality rate and peak NT-proBNP levels. The relative risks of 60-day mortality, shock development, use of inotropes/vasopressors, mechanical ventilation, and extracorporeal life support were 9.2 (95% confidence interval: 3.3-25.3), 10.1 (4.3-24), 2.7 (1.4-5.2), 2.3 (1.4-3.7), and 5.7 (1.4-23.1), respectively. Conclusions: The baseline AST/ALT ratio can be a predictor of shock, multiorgan failure, and mortality in patients with a pulmonary embolism.

Evaluation of myocardial work changes after lung resection-the significance of surgical approach: an echocardiographic comparison between VATS and thoracotomy

OBJECTIVE

Considering the controversial benefits of video-assisted thoracoscopic surgery (VATS), we intended to evaluate the impact of surgical approach on cardiac function after lung resection using myocardial work analysis.

METHODS

Echocardiographic data of 48 patients (25 thoracotomy vs. 23 VATS) were retrospectively analyzed. All patients underwent transthoracic echocardiography (TTE) within 2 weeks before and after surgery, including two-dimensional speckle tracking and tissue Doppler imaging.

RESULTS

No notable changes in left ventricular (LV) function, assessed mainly using the LV global longitudinal strain (GLS), global myocardial work index (GMWI), and global work efficiency (GWE), were observed. Right ventricular (RV) TTE values, including tricuspid annular plane systolic excursion (TAPSE), tricuspid annular systolic velocity (TASV), right ventricular global longitudinal strain (RVGLS), and RV free-wall GLS (RVFWGLS), indicated greater RV function impairment in the thoracotomy group than in the VATS group [TAPSE(mm) 17.90 ± 3.80 vs. 21.00 ± 3.48, p = 0.006; d = 0.84; TASV(cm/s): 12.40 ± 2.90 vs. 14.70 ± 2.40, p = 0.004, d = 0.86; RVGLS(%): - 16.00 ± 4.50 vs. - 19.40 ± 2.30, p = 0.012, d = 0.20; RVFWGLS(%): - 11.50 ± 8.50 vs. - 18.31 ± 5.40, p = 0.009, d = 0.59; respectively].

CONCLUSIONS

Unlike RV function, LV function remained preserved after lung resection. The thoracotomy group exhibited greater RV function impairment than did the VATS group. Further studies should evaluate the long-term impact of surgical approach on cardiac function.

A new approach towards extracorporeal gas exchange and first in vitro results

OBJECTIVES

Extracorporeal life support (ECLS) pertains to therapeutic and prophylactic techniques utilized in a wide range of medical applications, with severe pulmonary diseases being the most prominent cases. Over the past decades, little progress has been made in advancing the basic principles and properties of gas exchangers. Here, in an unconventional approach, dialysis hollow fibers are handled with silicone to create a purely diffusive coating that prevents plasma leakage and promotes gas exchange.

METHODS

Commercial dialyzers of varying surface area and fiber diameter have been coated with silicone, to determine the impact of each parameter on performance. The impermeability of the silicone layer has been validated by pressurization and imaging methods. SEM images have revealed a homogeneous silicone film coating the lumen of the capillaries, while fluid dynamic investigations have confirmed its purely diffusive nature.

RESULTS

The hemodynamic behavior and the gas exchange efficiency of the silicone-coated prototypes have been investigated in vitro with porcine blood under various operating conditions. Their performance has been found to be similar to that of a commercial PMP oxygenator.

CONCLUSIONS

This novel class of gas exchangers is characterized by high versatility and expeditious manufacturing. Intraoperability between conventional ECLS systems and dialysis machines broadens the range of application infinitely. Ultimately, long-term clinical applicability ought to be determined over in vivo animal investigations.

Amitriptyline inhibits bronchoconstriction and directly promotes dilatation of the airways

INTRODUCTION

The standard therapy for bronchial asthma consists of combinations of acute (short-acting ß2-sympathomimetics) and, depending on the severity of disease, additional long-term treatment (including inhaled glucocorticoids, long-acting ß2-sympathomimetics, anticholinergics, anti-IL-4R antibodies). The antidepressant amitriptyline has been identified as a relevant down-regulator of immunological TH2-phenotype in asthma, acting-at least partially-through inhibition of acid sphingomyelinase (ASM), an enzyme involved in sphingolipid metabolism. Here, we investigated the non-immunological role of amitriptyline on acute bronchoconstriction, a main feature of airway hyperresponsiveness in asthmatic disease.

METHODS

After stimulation of precision cut lung slices (PCLS) from mice (wildtype and ASM-knockout), rats, guinea pigs and human lungs with mediators of bronchoconstriction (endogenous and exogenous acetylcholine, methacholine, serotonin, endothelin, histamine, thromboxane-receptor agonist U46619 and leukotriene LTD4, airway area was monitored in the absence of or with rising concentrations of amitriptyline. Airway dilatation was also investigated in rat PCLS by prior contraction induced by methacholine. As bronchodilators for maximal relaxation, we used IBMX (PDE inhibitor) and salbutamol (ß2-adrenergic agonist) and compared these effects with the impact of amitriptyline treatment. Isolated perfused lungs (IPL) of wildtype mice were treated with amitriptyline, administered via the vascular system (perfusate) or intratracheally as an inhalation. To this end, amitriptyline was nebulized via pariboy in-vivo and mice were ventilated with the flexiVent setup immediately after inhalation of amitriptyline with monitoring of lung function.

RESULTS

Our results show amitriptyline to be a potential inhibitor of bronchoconstriction, induced by exogenous or endogenous (EFS) acetylcholine, serotonin and histamine, in PCLS from various species. The effects of endothelin, thromboxane and leukotrienes could not be blocked. In acute bronchoconstriction, amitriptyline seems to act ASM-independent, because ASM-deficiency (Smdp1-/-) did not change the effect of acetylcholine on airway contraction. Systemic as well as inhaled amitriptyline ameliorated the resistance of IPL after acetylcholine provocation. With the flexiVent setup, we demonstrated that the acetylcholine-induced rise in central and tissue resistance was much more marked in untreated animals than in amitriptyline-treated ones. Additionally, we provide clear evidence that amitriptyline dilatates pre-contracted airways as effectively as a combination of typical bronchodilators such as IBMX and salbutamol.

CONCLUSION

Amitriptyline is a drug of high potential, which inhibits acute bronchoconstriction and induces bronchodilatation in pre-contracted airways. It could be one of the first therapeutic agents in asthmatic disease to have powerful effects on the TH2-allergic phenotype and on acute airway hyperresponsiveness with bronchoconstriction, especially when inhaled.

In vitro evaluation of the performance of an oxygenator depending on the non-standard gas content of the inlet blood with special regard on CO2 elimination

INTRODUCTION

The performance of an oxygenator, as found in literature, is evaluated according to protocols that define standard values of the gas content in the inlet blood. However, when dealing with simulations of lung insufficiency, a more extensive evaluation is needed. This work aims to investigate and assess the gas exchange performance of an oxygenator for different input values of gas content in blood.

METHODS

Three commercially available oxygenators with different membrane surfaces were investigated in a mock loop for three blood flow rates (0.5l/min, 1l/min, and 5l/min) and two gas-to-blood ratios (1:1, and 15:1). The initial CO2 and O2 partial pressures (pCO2 and pO2) in blood were set to ≥ 100 mmHg and ≤10 mmHg, respectively. For each ratio, the efficiency, defined as the ratio between the difference of pressure inlet and outlet and the inlet pCO2 (pCO2(i)), was calculated.

RESULTS

The CO2 elimination in an oxygenator was higher for higher pCO2(i). While for a pCO2(i) of 100 mmHg, an oxygenator eliminated 80 mmHg, the same oxygenator at the same conditions eliminated 5 mmHg CO2 when pCO2(i) was 10 mmHg. The efficiency of the oxygenator decreased from 76,9% to 49,5%. For simulation reasons, the relation between the pCO2(i) and outlet (pCO2(o)) for each oxygenator at different blood and gas flows, was described as an exponential formula.

CONCLUSION

The performance of an oxygenator in terms of CO2 elimination depends not only on the blood and gas flow, but also on the initial pCO2 value. This dependence is crucial for simulation studies in the future.

Computational fluid dynamics analysis of endoluminal aortic perfusion

INTRODUCTION

In peripheral percutaneous (VA) extracorporeal membrane oxygenation (ECMO) procedures the femoral arteries perfusion route has inherent disadvantages regarding poor upper body perfusion due to watershed. With the advent of new long flexible cannulas an advancement of the tip up to the ascending aorta has become feasible. To investigate the impact of such long endoluminal cannulas on upper body perfusion, a Computational Fluid Dynamics (CFD) study was performed considering different support levels and three cannula positions.

METHODS

An idealized literature-based- and a real patient proximal aortic geometry including an endoluminal cannula were constructed. The blood flow was considered continuous. Oxygen saturation was set to 80% for the blood coming from the heart and to 100% for the blood leaving the cannula. 50% and 90% venoarterial support levels from the total blood flow rate of 6 l/min were investigated for three different positions of the cannula in the aortic arch.

RESULTS

For both geometries, the placement of the cannula in the ascending aorta led to a superior oxygenation of all aortic blood vessels except for the left coronary artery. Cannula placements at the aortic arch and descending aorta could support supra-aortic arteries, but not the coronary arteries. All positions were able to support all branches with saturated blood at 90% flow volume.

CONCLUSIONS

In accordance with clinical observations CFD analysis reveals, that retrograde advancement of a long endoluminal cannula can considerably improve the oxygenation of the upper body and lead to oxygen saturation distributions similar to those of a central cannulation.

Inflow from a Cardiopulmonary Assist System to the Pulmonary Artery and Its Implications for Local Hemodynamics-a Computational Fluid Dynamics Study

When returning blood to the pulmonary artery (PA), the inflow jet interferes with local hemodynamics. We investigated the consequences for several connection scenarios using transient computational fluid dynamics simulations. The PA was derived from CT data. Three aspects were varied: graft flow rate, anastomosis location, and inflow jet path length from anastomosis site to impingement on the PA wall. Lateral anastomosis locations caused abnormal flow distribution between the left and right PA. The central location provided near-physiological distribution but induced higher wall shear stress (WSS). All effects were most pronounced at high graft flows. A central location is beneficial regarding flow distribution, but the resulting high WSS might promote detachment of local thromboembolisms or influence the autonomic nervous innervation. Lateral locations, depending on jet path length, result in lower WSS at the cost of an unfavorable flow distribution that could promote pulmonary vasculature changes. Case-specific decisions and further research are necessary.

Extracorporeal Artificial Lungs: Co-Creating Future Technology - A Qualitative Analysis

Background

Terminal lung diseases such as chronic obstructive pulmonary disease (COPD) and pulmonary hypertension (PH) in progression cause a large reduction in quality of life and may lead to bilateral lung transplantation (bLTx). An artificial portable lung could provide a bridge to lung transplantation, allowing patients to remain at home and mobile for longer. To advance the development of such an artificial lung, patient feedback is essential. The aim of this study is to analyze patient acceptance about an extracorporeal artificial lung and to implement these findings into the development.

Methods

In collaboration with a medical device developer, we presented a portable dummy oxygenator to patients with advanced lung disease, as potential end users. Data collection in Germany and France was based on two different methods: an online questionnaire and face-to-face interviews (F2F).

Results

A total of 604 participants answered the online questionnaire and 17 participants were included in the F2F interviews. The majority of participants (COPD n=140, PH n=17) were able to walk more than 1 km with a mean suffering pressure of 2.87 and 3, respectively. Six of the 17 F2F participants who could walk <1 km were interested in an assistive device. The statistical value of Fisher's exact test for suffering pressure and desire for a portable oxygenator was 0.45.

Conclusion

In patients with advanced lung disease, there is no statistically significant association between subjectively increased suffering pressure and desire for a portable oxygenator, so market introduction may be difficult. Potential end users should be implemented early in device development. Data collection via an online questionnaire combined with personal interviews has proven to be a successful approach here.

Oxygenation performance assessment of an artificial lung in different central anatomic configurations

OBJECTIVES

Aim of this work was to characterize possible central anatomical configurations in which a future artificial lung (AL) could be connected, in terms of oxygenation performance.

METHODS

Pulmonary and systemic circulations were simulated using a numerical and an in vitro approach. The in vitro simulation was carried out in a mock loop in three phases: (1) normal lung, (2) pulmonary shunt (50% and 100%), and (3) oxygenator support in three anatomical configurations: right atrium-pulmonary artery (RA-PA), pulmonary artery-left atrium (PA-LA), and aorta-left atrium (Ao-LA). The numerical simulation was performed for the oxygenator support phase. The oxygen saturation (SO₂) of the arterial blood was plotted over time for two percentages of pulmonary shunt and three blood flow rates through the oxygenator.

RESULTS

During the pulmonary shunt phase, SO₂ reached a steady state value (of 68% for a 50% shunt and of nearly 0% for a 100% shunt) 20 min after the shunt was set. During the oxygenator support phase, physiological values of SO₂ were reached for RA-PA and PA-LA, in case of a 50% pulmonary shunt. For the same conditions, Ao-LA could reach a maximum SO₂ of nearly 60%. Numerical results were congruous to the in vitro simulation ones.

CONCLUSIONS

Both in vitro and numerical simulations were able to properly characterize oxygenation properties of a future AL depending on its placement. Different anatomical configurations perform differently in terms of oxygenation. Right to right and right to left connections perform better than left to left ones.

Minimally Invasive Central Cannulation for Extracorporeal Life Support: The Uniportal and Subxiphoid Approach

OBJECTIVE

Extracorporeal life support (ECLS) for circulatory and/or respiratory failure is improving. Currently, invasive sternotomies or rib-spreading thoracotomies are used for central cannulation of the heart and great vessels. Although peripheral cannulation of the extremities is often used, this approach may result in immobility and unintentional dislodgement. Less invasive methods for central cannulation are needed to achieve long-term ECLS. The objective of this study was to develop 2 different minimally invasive approaches for central thoracic cannulation.

METHODS

Porcine hearts were positioned in a plastic thoracic model. An endoscopic camera and multiple endoscopic instruments were used. Both access points, uniportal (lateral) and subxiphoidal, were simulatively investigated. A novel cannulation method using purse string sutures, a custom-made endoscopic puncture tool, guidewires, and dilator-assisted cannulas was developed. Simulations were tested in a closed circuit regarding leak tightness.

RESULTS

The uniportal approach allowed a cannulation of the aorta, inferior vena cava, right atrium, and main pulmonary artery. Cannulation of the right branches of the pulmonary artery and vein was also possible. From the subxiphoid approach, cannulation of the aorta, main pulmonary artery, and both atria were possible. Subsequent evaluation and leakage tests revealed no damage to the surrounding structures and tightly sealed cannulation sites. The uniportal approach was also successfully performed in a human cadaver to connect the aorta and right atrium with cannulas from the subxiphoidal space.

CONCLUSIONS

Both uniportal and subxiphoid central cannulation of potential sites for ECLS were feasible. This study encourages further investigation and potential clinical translation of minimally invasive central organ support.

Platelet-derived growth factor (PDGF)-BB regulates the airway tone via activation of MAP2K, thromboxane, actin polymerisation and Ca2+-sensitisation

BACKGROUND

PDGFR-inhibition by the tyrosine kinase inhibitor (TKI) nintedanib attenuates the progress of idiopathic pulmonary fibrosis (IPF). However, the effects of PDGF-BB on the airway tone are almost unknown. We studied this issue and the mechanisms beyond, using isolated perfused lungs (IPL) of guinea pigs (GPs) and precision-cut lung slices (PCLS) of GPs and humans.

METHODS

IPL: PDGF-BB was perfused after or without pre-treatment with the TKI imatinib (perfused/nebulised) and its effects on the tidal volume (TV), the dynamic compliance (Cdyn) and the resistance were studied.

PCLS (GP)

The bronchoconstrictive effects of PDGF-BB and the mechanisms beyond were evaluated. PCLS (human): The bronchoconstrictive effects of PDGF-BB and the bronchorelaxant effects of imatinib were studied. All changes of the airway tone were measured by videomicroscopy and indicated as changes of the initial airway area.

RESULTS

PCLS (GP/human): PDGF-BB lead to a contraction of airways. IPL: PDGF-BB decreased TV and Cdyn, whereas the resistance did not increase significantly. In both models, inhibition of PDGFR-(β) (imatinib/SU6668) prevented the bronchoconstrictive effect of PDGF-BB. The mechanisms beyond PDGF-BB-induced bronchoconstriction include activation of MAP2K and TP-receptors, actin polymerisation and Ca²⁺-sensitisation, whereas the increase of Ca²⁺ itself and the activation of EP_1-4-receptors were not of relevance. In addition, imatinib relaxed pre-constricted human airways.

CONCLUSIONS

PDGFR regulates the airway tone. In PCLS from GPs, this regulatory mechanism depends on the β-subunit. Hence, PDGFR-inhibition may not only represent a target to improve chronic airway disease such as IPF, but may also provide acute bronchodilation in asthma. Since asthma therapy uses topical application. This is even more relevant, as nebulisation of imatinib also appears to be effective.

Video-Assisted Thoracoscopic Surgery Management of Subacute Retained Blood Syndrome after Cardiac Surgery

PURPOSE

Blood loss along with inadequate evacuation after cardiac surgery leads to retained blood syndrome (RBS) in the pleural and/or pericardial cavity. Re-sternotomy is often needed for clot evacuation. Video-assisted thoracoscopic surgery (VATS) evacuation is a less-invasive procedure. However, sufficient evidence on safety and outcomes is lacking.

METHODS

Thirty patients who developed hemothorax and/or hemopericardium after cardiac surgery and underwent VATS evacuation between April 2015 and September 2020 were included in this retrospective single-center analysis.

RESULTS

The median patient age was 70 (interquartile range: IQR 62-75) years, body mass index (BMI) was 24.7 (IQR 22.8-29) kg/m2, time between initial cardiac surgery and VATS was 17 (IQR 11-21) days, 30% of the patients were female, 60% resided in the ICU, and 17% were nicotine users. Coronary artery bypass graft was the most frequent initial cardiac procedure. Median operation time was 120 (IQR 90-143) min, 23% of the patients needed an additional VATS, and the median length of hospital stay after VATS was 8 (IQR 5-14) days. All patients survived VATS, and we experienced no mortality related to the VATS procedure.

CONCLUSION

In our study, VATS for evacuation of RBS after cardiac surgery was a feasible, safe, and efficient alternative approach to re-sternotomy in selected patients.

A polyurethane-based surgical adhesive for sealing blood vessel anastomoses-A feasibility study in pigs

Peri- and postoperative anastomotic leakage from blood vessel anastomosis is a common and potentially life-threatening complication. As an adjunctive therapy providing an additional layer of safety, a new biodegradable, polyurethane-based adhesive was developed. It consists of two components: an isocyanate-functionalized prepolymer and an amino-based curing agent. The adhesive was investigated in a porcine animal model to seal sutured blood vessel anastomoses of arteries, veins, aortas and prosthetic aortic graft replacements. The material-determined properties of the adhesive like viscosity, processing and polymerization time as well as bonding strength were well suited for this application. The adhesive stopped perioperative suture-line bleedings and stayed on all anastomoses until sacrifice. Hematological and serological inflammation marker assessments were unobtrusive. The histological evaluation showed a mild to moderate local tissue reaction to the adhesive constituting a physiological, non-adverse tissue-biomaterial interaction. The adhesive did not interfere with vascular wound healing. The adhesive demonstrated to be suitable to improve the outcome of cardiovascular surgeries by securing the classical sutured anastomoses in a fast, easy and safe manner. However, further studies are required to quantitatively evaluate efficacy in terms of anastomotic leakage prevention as well as long-term tissue compatibility and degradation.

Extracorporeal membrane oxygenation in patients with COVID-19: 1-year experience

Background

Extracorporeal membrane oxygenation (ECMO) in patients with coronavirus disease 2019 (COVID-19) showed reasonable outcomes. However, recent studies indicated a negative trend and analysis is needed.

Methods

Baseline characteristics, laboratory parameters, and outcomes of ECMO-supported patients with COVID-19 were analyzed in a retrospective single-center study. We included hospital admissions until February 28, 2021; patients were followed until discharge/death. Eventually, we compared data between patients hospitalized before and after September 1, 2020.

Results

Median age of patients treated with ECMO (n=39) was 56 years; most patients were males (n=28, 72%). Median mechanical ventilation time (prior to ECMO) was 6 days, while the median ECMO duration was 19 days. Overall survival rate was 41%. In the sub-analysis, survival until discharge in the first and second epidemic waves was 53% (n=19) and 30% (n=20), respectively (P=0.2). At baseline, compared with patients of the first wave, those of the second wave had higher median body mass index (28.2 vs. 31.1 kg/m², respectively, P=0.02), bicarbonate (27 vs. 31.8 mmol/L, respectively, P=0.033), plasma free hemoglobin (36 vs. 58 mg/L, respectively, P=0.013), alanine aminotransferase (33 vs. 52 U/L, respectively, P=0.018), and pH (7.29 vs. 7.42, respectively, P=0.005), lower rate of pulmonary hypertension (32% vs. 0%, respectively, P=0.008), lower positive end-expiratory pressure (14 vs. 12 cmH₂O, respectively, P=0.04), longer median ECMO duration (16 vs. 24.5 days, respectively, P=0.074), and more frequent major bleeding events (42% vs. 80%, respectively, P=0.022).

Conclusions

ECMO-supported patients with COVID-19 had an overall survival rate of 41%. Similar to international registries, we observed less favorable outcomes during the second wave. Further research is needed to confirm this signal and find predictors for mortality.

Efficacy of a Novel Medical Adhesive for Sealing Lung Parenchyma: An in vitro Study in Rabbit Lungs

INTRODUCTION

During thoracic resection procedures, complete hemostasis and aerostasis are priorities. A persistent alveolar air leak is associated with increased morbidity and mortality rates. This study aimed to evaluate whether the novel medical adhesive VIVO (Adhesys Medical GmbH Aachen, Germany) is a reliable alternative sealing technique to routine surgical procedures.

METHODS

We conducted an in vitro animal study by analyzing 21 lungs of New Zealand (n = 19) and Chinchilla Bastard (n = 2) rabbits (age, 11-18 weeks; weight, 2,400-3,600 g). Three groups, each comprising 7 animals, were evaluated. VIVO (VIVO-group) was compared with standard surgical lung parenchymal lesion closure with a polypropylene suture (Suture-group) and TachoSil® (TachoSil-group). We adopted a stable, pressure-controlled ventilation protocol. After explantation, a surgical incision 0.5-cm deep and 1.5-cm wide was made in the lungs using a customized template. Air leak was measured quantitatively (mL/min) using a respirator and visualized qualitatively by 2 observers who made independent judgments. Next, the leak was closed using VIVO, suture, or TachoSil® as specified by the manufacturer. Subsequently, positive end-expiratory pressure (PEEP) and inspiratory pressure were gradually increased until a maximum of 15 and 30 mbar were attained, respectively.

RESULTS

At PEEPs of 8, 10, and 15 mbar, VIVO achieved complete sealing of the profound parenchymal defect in all (n = 7) lungs. After closure of the incision, we observed an air leak variation of 127 ± 114 mL/min (Suture-group), 31 ± 49 mL/min (VIVO-group), and 114 ± 134 mL/min (TachoSil-group). VIVO showed a significantly lower air leak than surgical sutures (p = 0.031) and TachoSil® (p = 0.046).

CONCLUSION

VIVO offers sufficient closure of the lung parenchymal lesions. The novel adhesive enabled significantly better sealing with lower persistent air leakage than TachoSil® or surgical sutures. Further investigation using in vivo models is strongly encouraged to confirm our findings.

Outcomes of Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome in COVID-19 Patients: A Propensity-Matched Analysis

It remains unclear to what extent the outcomes and complications of extracorporeal membrane oxygenation (ECMO) therapy in COVID-19 patients with acute respiratory distress syndrome (ARDS) differ from non-COVID-19 ARDS patients. In an observational, propensity-matched study, outcomes after ECMO support were compared between 19 COVID-19 patients suffering from ARDS (COVID group) and 34 matched non-COVID-19 ARDS patients (NCOVID group) from our historical cohort. A 1:2 propensity matching was performed based on respiratory ECMO survival prediction (RESP) score, age, gender, bilirubin, and creatinine levels. Patients' characteristics, laboratory parameters, adverse events, and 90-day survival were analyzed. Patients' characteristics in COVID and NCOVID groups were similar. Before ECMO initiation, fibrinogen levels were significantly higher in the COVID group (median: 493 vs. 364 mg/dL, p < 0.001). Median ECMO support duration was similar (16 vs. 13 days, p = 0.714, respectively). During ECMO therapy, patients in the COVID group developed significantly more thromboembolic events (TEE) than did those in the NCOVID group (42% vs. 12%, p = 0.031), which were mainly pulmonary artery embolism (PAE) (26% vs. 0%, p = 0.008). The rate of major bleeding events (42% vs. 62%, p = 0.263) was similar. Fibrinogen decreased significantly more in the COVID group than in the NCOVID group (p < 0.001), whereas D-dimer increased in the COVID group (p = 0.011). Additionally, 90-day mortality did not differ (47% vs. 74%; p = 0.064) between COVID and NCOVID groups. Compared with that in non-COVID-19 ARDS patients, ECMO support in COVID-19 patients was associated with comparable in-hospital mortality and similar bleeding rates but a higher incidence of TEE, especially PAE. In contrast, coagulation parameters differed between COVID and NCOVID patients.

Thromboembolic and Bleeding Events in COVID-19 Patients receiving Extracorporeal Membrane Oxygenation

Background Extracorporeal membrane oxygenation (ECMO) is a potential treatment option in critically ill COVID-19 patients suffering from acute respiratory distress syndrome (ARDS) if mechanical ventilation (MV) is insufficient; however, thromboembolic and bleeding events (TEBE) during ECMO treatment still need to be investigated.

Methods We conducted a retrospective, single-center study including COVID-19 patients treated with ECMO. Additionally, we performed a univariate analysis of 85 pre-ECMO variables to identify factors influencing incidences of thromboembolic events (TEE) and bleeding events (BE), respectively.

Results Seventeen patients were included; the median age was 57 years (interquartile range [IQR]: 51.5–62), 11 patients were males (65%), median ECMO duration was 16 days (IQR: 10.5–22), and the overall survival was 53%. Twelve patients (71%) developed TEBE. We observed 7 patients (41%) who developed TEE and 10 patients (59%) with BE. Upper respiratory tract (URT) bleeding was the most frequent BE with eight cases (47%). Regarding TEE, pulmonary artery embolism (PAE) had the highest incidence with five cases (29%). The comparison of diverse pre-ECMO variables between patients with and without TEBE detected one statistically significant value. The platelet count was significantly lower in the BE group (n = 10) than in the non-BE group (n = 7) with 209 (IQR: 145–238) versus 452 G/L (IQR: 240–560), with p = 0.007.

Conclusion This study describes the incidences of TEE and BE in critically ill COVID-19 patients treated with ECMO. The most common adverse event during ECMO support was bleeding, which occurred at a comparable rate to non-COVID-19 patients treated with ECMO.

Role of extracorporeal membrane oxygenation in critically Ill COVID-19 patients and predictors of mortality

The role of extracorporeal membrane oxygenation (ECMO) in the management of critically ill COVID‐19 patients remains unclear. Our study aims to analyze the outcomes and risk factors from patients treated with ECMO. This retrospective, single‐center study includes 17 COVID‐19 patients treated with ECMO. Univariate and multivariate parametric survival regression identified predictors of survival. Nine patients (53%) were successfully weaned from ECMO and discharged. The incidence of in‐hospital mortality was 47%. In a univariate analysis, only four out of 83 pre‐ECMO variables were significantly different; IL‐6, PCT, and NT‐proBNP were significantly higher in non‐survivors than in survivors. The Respiratory Extracorporeal Membrane Oxygenation Survival Prediction (RESP) score was significantly higher in survivors. After a multivariate parametric survival regression, IL‐6, NT‐proBNP and RESP scores remained significant independent predictors, with hazard ratios (HR) of 1.069 [95%‐CI: 0.986‐1.160], P = .016 1.001 [95%‐CI: 1.000‐1.001], P = .012; and .843 [95%‐CI: 0.564‐1.260], P = .040, respectively. A prediction model comprising IL‐6, NT‐proBNP, and RESP score showed an area under the curve (AUC) of 0.87, with a sensitivity of 87.5% and 77.8% specificity compared to an AUC of 0.79 for the RESP score alone. The present study suggests that ECMO is a potentially lifesaving treatment for selected critically ill COVID‐19 patients. Considering IL‐6 and NT‐pro‐BNP, in addition to the RESP score, may enhance outcome predictions.

Prolonged Survival of a Patient with Advanced-Stage Combined Hepatocellular-Cholangiocarcinoma

Combined hepatocellular-cholangiocarcinoma (cHCC/CCA) represents a rare type of primary liver cancer with a very limited prognosis. Although just recently genomic studies have contributed to a better understanding of the disease's genetic landscape, therapeutic options, especially for advanced-stage patients, are limited and often experimental, as no standardized treatment protocols have been established to date. Here, we report the case of a 38-year-old male patient who was diagnosed with extensive intrahepatic cHCC/CCA in an otherwise healthy liver without signs of chronic liver disease. An interdisciplinary stepwise therapeutic approach including locoregional liver-targeted therapy, systemic chemotherapy, liver transplantation, surgical pulmonary metastasis resection, and next-generation sequencing-based targeted therapy led to a prolonged overall survival beyond 5 years with an excellent quality of life. This case report comprises several provocative treatment decisions that are extensively discussed in light of the existing literature on this rare but highly aggressive malignancy.

Levosimendan reduces segmental pulmonary vascular resistance in isolated perfused rat lungs and relaxes human pulmonary vessels

INTRODUCTION

Levosimendan is approved for acute heart failure. Within this context, pulmonary hypertension represents a frequent co-morbidity. Hence, the effects of levosimendan on segmental pulmonary vascular resistance (PVR) are relevant. So far, this issue has been not studied. Beyond that the relaxant effects of levosimendan in human pulmonary vessel are unknown. We addressed these topics in rats' isolated perfused lungs (IPL) and human precision-cut lung slices (PCLS).

MATERIAL AND METHODS

In IPL, levosimendan (10 μM) was perfused in untreated and endothelin-1 pre-contracted lungs. The pulmonary arterial pressure (PPA) was continuously recorded and the capillary pressure (Pcap) was determined by the double-occlusion method. Thereafter, segmental PVR, expressed as precapillary (Rpre) and postcapillary resistance (Rpost) and PVR were calculated. Human PCLS were prepared from patients undergoing lobectomy. Levosimendan-induced relaxation was studied in naïve and endothelin-1 pre-contracted PAs and PVs. In endothelin-1 pre-contracted PAs, the role of K+-channels was studied by inhibition of KATP-channels (glibenclamide), BKCa2+-channels (iberiotoxin) and Kv-channels (4-aminopyridine). All changes of the vascular tone were measured by videomicroscopy. In addition, the increase of cAMP/GMP due to levosimendan was measured by ELISA.

RESULTS

Levosimendan did not relax untreated lungs or naïve PAs and PVs. In IPL, levosimendan attenuated the endothelin-1 induced increase of PPA, PVR, Rpre and Rpost. In human PCLS, levosimendan relaxed pre-contracted PAs or PVs to 137% or 127%, respectively. In pre-contracted PAs, the relaxant effect of levosimendan was reduced, if KATP- and Kv-channels were inhibited. Further, levosimendan increased cGMP in PAs/PVs, but cAMP only in PVs.

DISCUSSION

Levosimendan reduces rats' segmental PVR and relaxes human PAs or PVs, if the pulmonary vascular tone is enhanced by endothelin-1. Regarding levosimendan-induced relaxation, the activation of KATP- and Kv-channels is of impact, as well as the formation of cAMP and cGMP. In conclusion, our results suggest that levosimendan improves pulmonary haemodynamics, if PVR is increased as it is the case in pulmonary hypertension.

Long-Term Venovenous Connection for Extracorporeal Carbon Dioxide Removal (ECCO2R)-Numerical Investigation of the Connection to the Common Iliac Veins

Purpose

Currently used cannulae for extracorporeal carbon dioxide removal (ECCO₂R) are associated with complications such as thrombosis and distal limb ischemia, especially for long-term use. We hypothesize that the risk of these complications is reducible by attaching hemodynamically optimized grafts to the patient’s vessels. In this study, as a first step towards a long-term stable ECCO₂R connection, we investigated the feasibility of a venovenous connection to the common iliac veins. To ensure its applicability, the drainage of reinfused blood (recirculation) and high wall shear stress (WSS) must be avoided.

Methods

A reference model was selected for computational fluid dynamics, on the basis of the analysis of imaging data. Initially, a sensitivity analysis regarding recirculation was conducted using as variables: blood flow, the distance of drainage and return to the iliocaval junction, as well as the diameter and position of the grafts. Subsequently, the connection was optimized regarding recirculation and the WSS was evaluated. We validated the simulations in a silicone model traversed by dyed fluid.

Results

The simulations were in good agreement with the validation measurements (mean deviation 1.64%). The recirculation ranged from 32.1 to 0%. The maximum WSS did not exceed 5.57 Pa. The position and diameter of the return graft show the highest influence on recirculation. A correlation was ascertained between recirculation and WSS. Overall, an inflow jet directed at a vessel wall entails not only high WSS, but also a flow separation and thereby an increased recirculation. Therefore, return grafts aligned to the vena cava are crucial.

Conclusion

In conclusion, a connection without recirculation could be feasible and therefore provides a promising option for a long-term ECCO₂R connection.

Awake Thoracic Surgery with Extracorporeal Membrane Oxygenation

A 75-year old patient with a right sided secondary pneumothorax and prolonged air leak showed upper lobe predominant bullous emphysema. Due to the patients extremely reduced general condition neither an open approach nor a thoracoscopic approach seemed possible. Hence, we performed an awake lung volume reduction surgery with perioperative single site veno-venous extracorporeal membrane oxygenation. No heparin was administered. The extracorporeal membrane oxygenation (ECMO) could be weaned up to the second postoperative day. The further postoperative course was uneventful. This current case suggests that combining awake surgery with extracorporeal membrane oxygenation could be a future concept in extremely compromised patients.

A New Percutaneous Approach to Treat Combined Right Ventricular and Respiratory Failure: The "Aachen Cannula"

INTRODUCTION

Right ventricular failure (RVF) on its own is a life-threatening condition. Often it manifests as a two-organ failure in the final phase of several lung diseases. Mechanical circulatory support is a proven treatment of RVF but remains challenging. Our objective is to develop a novel, simplified, and minimally invasive cannula approach to treat both RVF and respiratory failure.

METHODS

We conceptualized a dual lumen cannula approach to allow oxygenated right-to-left shunting at an atrial level to decompress right-sided circulation. A minimally invasive approach through percutaneous, transjugular insertion and transseptal placement should enable patients to be non-sedated and even ambulatory. In an iterative design, pre-prototyping, prototyping, and anatomic fitting process, such a cannula was generated and tested in both cadaveric and fluid dynamic studies.

RESULTS

After various modifications and improvements, a 27-Fr 255-mm-long double-lumen cannula with an inner line (oxygenated blood return to patient into the left atrium) of 18 Fr and an inflatable balloon (with a volume of approximately 1 mL) at the outflow tip was produced - one version with a straight head and another one with a curved head. In our anatomic studies, the "Aachen Cannula" allowed an easy transjugular introduction and advancement into the right atrium by Seldinger technique. Transseptal placement was achieved by puncture (Brockenbrough needle) in combination with dilatation and was then secured in place with the stabilizing balloon, even under slight tension. The cannula prototype enabled a flow of up to 3.5 L/min, at which common pressure drops were observed.

CONCLUSION

In conclusion, we successfully conceptualized, designed, and verified a minimally invasive one-cannula approach for the treatment of either isolated right heart failure and even combined RVF and respiratory failure through our transseptal Aachen Cannula. This concept may also be carried out in ambulatory conditions. Moreover, this approach completely avoids recirculation issues and ensures reliable oxygenated coronary as well as cerebral perfusion.

Argon reduces the pulmonary vascular tone in rats and humans by GABA-receptor activation

Argon exerts neuroprotection. Thus, it might improve patients’ neurological outcome after cerebral disorders or cardiopulmonary resuscitation. However, limited data are available concerning its effect on pulmonary vessel and airways. We used rat isolated perfused lungs (IPL) and precision-cut lung slices (PCLS) of rats and humans to assess this topic. IPL: Airway and perfusion parameters, oedema formation and the pulmonary capillary pressure (P_cap) were measured and the precapillary and postcapillary resistance (R_post) was calculated. In IPLs and PCLS, the pulmonary vessel tone was enhanced with ET-1 or remained unchanged. IPLs were ventilated and PCLS were gassed with argon-mixture or room-air. IPL: Argon reduced the ET-1-induced increase of P_cap, R_post and oedema formation (p < 0.05). PCLS (rat): Argon relaxed naïve pulmonary arteries (PAs) (p < 0.05). PCLS (rat/human): Argon attenuated the ET-1-induced contraction in PAs (p < 0.05). Inhibition of GABA_B-receptors abolished argon-induced relaxation (p < 0.05) in naïve or ET-1-pre-contracted PAs; whereas inhibition of GABA_A-receptors only affected ET-1-pre-contracted PAs (p < 0.01). GABA_A/B-receptor agonists attenuated ET-1-induced contraction in PAs and baclofen (GABA_B-agonist) even in pulmonary veins (p < 0.001). PLCS (rat): Argon did not affect the airways. Finally, argon decreases the pulmonary vessel tone by activation of GABA-receptors. Hence, argon might be applicable in patients with pulmonary hypertension and right ventricular failure.

[Liquid biopsy in human non-small-cell lung cancer : Blood-based analysis of ctDNA methylation]

BACKGROUND

Use of liquid biopsy for minimal invasive follow-up diagnostics of non-small-cell lung carcinomas (NSCLCs).

OBJECTIVES

Systematic search for new putative blood-based hypermethylation biomarkers to discriminate NSCLC patients from patients without a malign disease.

METHODS

Quantitative analysis of gene promoter DNA methylation of potential biomarkers from cfDNA (plasma) with pyrosequencing.

RESULTS

cfDNA hypermethylation in plasma confirmed significant higher methylation frequencies of the candidate gene CFTR of the NSCLC patients compared to the combined control groups and to NSCLC patients after curative therapy of primary NSCLC (post-NSCLC). ROC-analysis of the best discriminatory CpGs of the CFTR promotor (CpG1-2-4) revealed a sensitivity of 52% in NSCLC patients and a specificity of 90% in the post-NSCLC group (AUC: 0.69; p < 0.05).

CONCLUSIONS

Promotor hypermethylation of the potential biomarker CFTR shows a discriminatory potential for differentiation of NSCLC patients to patients without a malign disease and should further be investigated.

The effects of zinc- and copper-containing welding fumes on murine, rat and human precision-cut lung slices

Recently, the pro-inflammatory effects of metal inert gas brazing welding fumes containing zinc and copper have been demonstrated in humans. Here, murine, rat and human precision cut lung slices (PCLS) were incubated in welding fume containing media with 0.1, 1, 10 and 100 μg/ml for 24 or 48 h. 24 h incubation were determined either by incubation for the total time or for only 6 h followed by a 18 h post-incubation phase. Cytotoxicity, proliferation and DNA repair rates, and cytokine levels were determined. Welding fume particle concentrations of 0.1 and 1 μg/ml showed no toxic effects on PCLS of all three species, while for 10 and 100 μg/ml a concentration-dependent toxicity occurred. Proliferation and DNA repair rates were reduced for all tested concentrations and incubation times. Additionally, the cytokine levels in the supernatants were markedly reduced, while after 6 h of exposure with 18 h of post-incubation time a trend towards increased cytokine levels occurred. PCLS are a reliable and feasible method to assess and offer a prediction of toxic effects of welding fume particles on human lungs. Rat PCLS showed similar responses compared to human PCLS and are suitable for further evaluation of toxic effects exerted by welding fume particles.

[Chest trauma from a surgical perspective]

Patients with multiple injuries in particular frequently also suffer from chest trauma. During the initial phase the identification and treatment of life-threatening injuries is essential and tension pneumothorax is of particular importance during this phase. The Advanced Trauma Life Support (ATLS) algorithm should be followed for structured treatment. In most cases treatment by insertion of a chest tube is sufficient but for some injuries an emergency thoracotomy is unavoidable as a life-saving intervention. In the further treatment especially a flail chest and retained hemothorax are responsible for complications, such as acute lung failure and thoracic empyema. Early operative interventions in the sense of rib fracture stabilization and thoracoscopy-assisted evacuation of hematomas can help to prevent such complications.

Ultrasound for In Vitro, Noninvasive Real-Time Monitoring and Evaluation of Tissue-Engineered Heart Valves

Tissue-engineered heart valves are developed in bioreactors where biochemical and mechanical stimuli are provided for extracellular matrix formation. During this phase, the monitoring possibilities are limited by the need to maintain the sterility and integrity of the valve. Therefore, noninvasive and nondestructive techniques are required. As such, optical imaging is commonly used to verify valve's functionality in vitro. It provides important information (i.e., leaflet symmetry, geometric orifice area, and closing and opening times), which is, however, usually limited to a singular view along the central axis from the outflow side. In this study, we propose ultrasound as a monitoring method that, in contrast to established optical imaging, can assess the valve from different planes, scanning the whole three-dimensional geometry. We show the potential benefits associated with the application of ultrasound to bioreactors, in advancing heart valve tissue engineering from design to fabrication and in vitro maturation. Specifically, we demonstrate that additional information, otherwise unavailable, can be gained to evaluate the valve's functionality (e.g., coaptation length, and effective cusp height and shape). Furthermore, we show that Doppler techniques provide qualitative visualization and quantitative evaluation of the flow through the valve, in real time and throughout the whole in vitro fabrication phase.

Tissue-Engineered Fibrin-Based Heart Valve with Bio-Inspired Textile Reinforcement

The mechanical properties of tissue-engineered heart valves still need to be improved to enable their implantation in the systemic circulation. The aim of this study is to develop a tissue-engineered valve for the aortic position - the BioTexValve - by exploiting a bio-inspired composite textile scaffold to confer native-like mechanical strength and anisotropy to the leaflets. This is achieved by multifilament fibers arranged similarly to the collagen bundles in the native aortic leaflet, fixed by a thin electrospun layer directly deposited on the pattern. The textile-based leaflets are positioned into a 3D mould where the components to form a fibrin gel containing human vascular smooth muscle cells are introduced. Upon fibrin polymerization, a complete valve is obtained. After 21 d of maturation by static and dynamic stimulation in a custom-made bioreactor, the valve shows excellent functionality under aortic pressure and flow conditions, as demonstrated by hydrodynamic tests performed according to ISO standards in a mock circulation system. The leaflets possess remarkable burst strength (1086 mmHg) while remaining pliable; pronounced extracellular matrix production is revealed by immunohistochemistry and biochemical assay. This study demonstrates the potential of bio-inspired textile-reinforcement for the fabrication of functional tissue-engineered heart valves for the aortic position.

The systemic inflammatory response syndrome following cardiac surgery: different expression of proinflammatory cytokines and procalcitonin in patients with and without multiorgan dysfunctions

Cardiopulmonary bypass is associated with an injury that may cause pathophysiological changes in the form of systemic inflammatory response syndrome (SIRS) or multiple organ dysfunction syndrome (MODS). In the present study, we investigated the inflammatory response of patients with multiple organ dysfunctions following open-heart surgery. Plasma levels of cytokines (IL-1β, IL-6, IL-8, IL-18) and procalcitonin (PCT) were measured on the first four postoperative days in 12 adult male patients with SIRS and two or more organ dysfunctions after myocar-dial revascularization (MODS group), and 15 patients without organ dysfunctions (SIRS group). All cytokines (except IL-1β) and PCT were significantly elevated in MODS patients, with peak values at the first two postoperative days. The results of our study show a different expression of members of the IL-1 family following extracorporeal circulation. For the first time, we can document that IL-18 is involved in the inflammatory response and the initiation of the MODS following cardiopulmonary bypass. In addition to APACHE-II score, PCT, IL-8, and IL-18 may be used as parameters for the prognosis of patients with organ dysfunctions after cardiac surgery. Furthermore, it must be noted that the duration of the surgical procedure is one of the most important factors for the initiation of the inflammatory response.

Does percutaneous dilatational tracheostomy increase the incidence of sternal wound infection - a single center retrospective of 4100 cases

BACKGROUND

The impact of percutaneous dilatational tracheostomy (PDT) on the development of post-median sternotomy wound infection (SWI) and mediastinitis is still controversial. We aimed to investigate the frequency of cross-infection and incidence of SWI after PDT.

METHODS

In a retrospective design, out of a total of 4100 procedures, all patients who had undergone median sternotomy and postoperative PDT were included from January 2010 to May 2013. For comparison of the pathogens isolated from SWIs, data from all patients who developed an SWI without a PDT during the aforementioned period were also analyzed. Demographical, pre-, peri- and post-operative data were compared. Microbiologic analysis from cultures of sternal and tracheal wounds was performed. Day and duration of tracheostomy were correlated to SWI occurrence.

RESULTS

Of the 265 patients who underwent a PDT, 25 (9.4 %) developed an SWI. In this cohort, identical pathogens were isolated from the tracheostomy and SWI in 36 % (9/25) of the patients. Of the pathogens isolated from the SWIs from the PDT + SWI group, 60 % were gram-positive bacteria, 20 % gram-negative bacteria and 20 % Candida spp. In the cross-infection group, the patients developed the following types of SWIs: 11.1 % CDC I, 55.6 % CDC II and 33.3 % mediastinitis (CDC III). The incidence of SWI in the group SWI + PDT was 9.4 % (9.4 % vs. 3.4 %, PDT + SWI and SWI w/oPDT , respectively, p = 0.0001). In group SWI w/oPDT , only 1.5 % (2/131 vs. 5/25; p = 0.001) Candida spp were isolated from SWI. The infection-related in-hospital mortality was high in groups PDT + SWI vs. SWI w/oPDT (20 % vs. 0 %, respectively; p = 0.0001). The statistical analysis did not demonstrate any correlation between time of performing PDT and occurrence of SWI.

CONCLUSIONS

There was a high incidence of microbial cross-infection from the PDTs to the sternal wounds in our study. We did not detect any correlation between the time of performing PDT and occurrence of SWI. According to our data, PDT seems to increase the incidence of SWI, especially caused by Candida spp., after cardiac surgery, which results in a prolonged hospital stay. Therefore, early antifungal prophylaxis after a PDT might be reasonable in high-risk patients on long-term mechanical ventilation if there is an impending SWI.

A personalized approach to interventional treatment of tricuspid regurgitation: experiences from an acute animal study

OBJECTIVES

Interventional treatment of tricuspid valve disease has so far received little attention due to the anatomical challenges in a thrombogenic surrounding. In the present study, we present an imaging-based, personalized interventional approach to the therapy of tricuspid regurgitation.

METHODS

In our porcine model, we used rapid prototyping to build a matrix reproducing the geometry of the right atrium that was previously derived from computer tomography (CT) scans. Over this matrix, a braided nitinol device fitting almost completely the right atrium was crafted. An additional tubular stent component was developed to carry a tissue valve prosthesis. This part was designed to be connectable to the annular portion of the main device. In our feasibility study, the crimped device was implanted via jugular access into the right atrium of 12 pigs and expanded subsequently. Following isolated implantation of the device without the valve-carrying component, further procedures included implantation of the whole composite device, including the mentioned tissue valve. Representing a only feasibility study, all implantations were performed under full bypass and direct sight. On-site visualization was performed by both echocardiography and fluoroscopy. Additional imaging was realized by postoperative CT scans.

RESULTS

Following implantation, 9 of 12 animals were weaned from cardiopulmonary bypass. Correct positioning of the device and orthodromic blood flow as maintained by the valve prosthesis were demonstrated by echocardiography and fluoroscopy. Postoperative contrast CT evaluation demonstrated proper fitting of the device into the right-sided heart cavities without obstruction of the outflow tract. Autopsy additionally confirmed its correct positioning without major trauma to surrounding structures.

CONCLUSIONS

We demonstrated the feasibility in principle of a personalized interventional treatment for tricuspid regurgitation using a braided stent, based on individual cardiac imaging, with anchoring forces mainly exerted on the venae cavae and on the inner surface of the right atrium. The design process of this device is a good indicator of the growing potential of an imaging-based personalized simulation and production approach for the treatment of tricuspid valve disease.

Video-assisted pericardioscopic surgery for epimyocardial lead implantation

PURPOSE

Video-assisted pericardioscopic surgery (VAPS) for epimyocardial lead implantation has demonstrated positive acute results concerning the safety and degree of freedom inside the pericardium. We evaluated the employment of a newly developed trocar for pericardioscopy with regard to long-term effects and feasibility of reoperation.

DESCRIPTION

Eight adult sheep were divided into three groups. In two animals, VAPS was used exclusively. All other animals received four small-caliber epicardial leads through VAPS. After 6 and 12 months (n = 3 each), reoperation was conducted for reevaluation of entry site, intrapericardial adhesions, lead position, and morphology of the implantation site.

EVALUATION

Reentry close to the previous entry site proves unproblematic. Adhesions were mild to moderate in the immediate area of the implanted leads. Throughout the follow-up, pacing parameters were satisfactory. Lead dislodgement occurred in 1 of 24 leads. The deployment of small-caliber flexible endoscopes through the new trocar provided sufficient navigation, stability, and maneuverability.

CONCLUSIONS

Reoperation from the same subxiphoid approach proved feasible. Lead removal and reimplantation were feasible at both 6 months and 12 months after initial implantation. The intrapericardial adhesions caused by VAPS alone are mild.

Oxygenated shunting from right to left: a feasibility study of minimized atrio-atrial extracorporeal membrane oxygenation for mid-term lung assistance in an acute ovine model

OBJECTIVES

Right ventricular failure is often the final phase in acute and chronic respiratory failure. We combined right ventricular unloading with extracorporeal oxygenation in a new atrio-atrial extracorporeal membrane oxygenation (ECMO).

METHODS

Eleven sheep (65 kg) were cannulated by a 28-Fr inflow cannula to the right atrium and a 25-Fr outflow cannula through the lateral left atrial wall. Both were connected by a serial combination of a microaxial pump (Impella Elect(®), Abiomed Europe, Aachen, Germany) and a membrane oxygenator (Novalung(®)-iLA membrane oxygenator; Novalung GmbH, Hechingen, Germany). In four animals, three subsequent states were evaluated: normal circulation, apneic hypoxia and increased right atrial after load by pulmonary banding. We focused on haemodynamic stability and gas exchange.

RESULTS

All animals reached the end of the study protocol. In the apnoea phase, the decrease in PaO2 (21.4 ± 3.6 mmHg) immediately recovered (179.1 ± 134.8 mmHg) on-device in continuous apnoea. Right heart failure by excessive after load decreased mean arterial pressure (59 ± 29 mmHg) and increased central venous pressure and systolic right ventricular pressure; PaO2 and SvO2 decreased significantly. On assist, mean arterial pressure (103 ± 29 mmHg), central venous pressure and right ventricular pressure normalized. The SvO2 increased to 89 ± 3% and PaO2 stabilized (129 ± 21 mmHg).

CONCLUSIONS

We demonstrated the efficacy of a miniaturized atrio-atrial ECMO. Right ventricular unloading was achieved, and gas exchange was well taken over by the Novalung. This allows an effective short- to mid-term treatment of cardiopulmonary failure, successfully combining right ventricular and respiratory bridging. The parallel bypass of the right ventricle and lung circulation permits full unloading of both systems as well as gradual weaning. Further pathologies (e.g. ischaemic right heart failure and acute lung injury) will have to be evaluated.