26 results on '"F. Schroeter"'
Search Results
2. Parent Hamiltonian for the non-Abelian chiral spin liquid
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Ronny Thomale, Martin Greiter, and Darrell F. Schroeter
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Physics ,Quantum Physics ,Annihilation ,Strongly Correlated Electrons (cond-mat.str-el) ,FOS: Physical sciences ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,symbols.namesake ,Condensed Matter - Strongly Correlated Electrons ,Quantum mechanics ,Thermodynamic limit ,symbols ,Abelian group ,Quantum spin liquid ,Hamiltonian (quantum mechanics) ,Quantum Physics (quant-ph) ,Mathematical physics - Abstract
We construct a parent Hamiltonian for the family of non-Abelian chiral spin liquids proposed recently by two of us [PRL 102, 207203 (2009)], which includes the Abelian chiral spin liquid proposed by Kalmeyer and Laughlin, as the special case S=1/2. As we use a circular disk geometry with an open boundary, both the annihilation operators we identify and the Hamiltonians we construct from these are exact only in the thermodynamic limit., 5+2 pages, no figures. Version 2: two references added
- Published
- 2012
3. Three-dimensional flux states as a model for the pseudogap phase of transition metal oxides
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Sebastian Doniach and Darrell F. Schroeter
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Physics ,Condensed Matter - Strongly Correlated Electrons ,Strongly Correlated Electrons (cond-mat.str-el) ,Mean field theory ,Condensed matter physics ,Neutron diffraction ,FOS: Physical sciences ,Flux ,Pseudogap ,Ground state ,Optical conductivity ,Intensity (heat transfer) ,Spectral line - Abstract
We propose that the pseudogap state observed in the transition metal oxides can be explained by a three-dimensional flux state, which exhibits spontaneously generated currents in its ground state due to electron-electron correlations. We compare the energy of the flux state to other classes of mean field states, and find that it is stabilized over a wide range of $t$ and $\delta$. The signature of the state will be peaks in the neutron diffraction spectra, the location and intensity of which are presented. The dependence of the pseudogap in the optical conductivity is calculated based on the parameters in the model., Comment: submitted to Phys. Rev. B on January 8, 2002
- Published
- 2002
4. New Insights into Mortality-Related Risk Factors in Infective Endocarditis: Results from the Brandenburg State Endocarditis Register.
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Ostovar R, Schroeter F, Seifi Zinab F, Fritzsche D, Minden HH, Lasheen N, Hartrumpf M, Ritter O, Dörr G, and Albes JM
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- Humans, Male, Female, Aged, Middle Aged, Time Factors, Risk Assessment, Prospective Studies, Risk Factors, Endocarditis mortality, Endocarditis surgery, Endocarditis diagnosis, Endocarditis microbiology, Germany epidemiology, Treatment Outcome, Aged, 80 and over, Endocarditis, Bacterial mortality, Endocarditis, Bacterial microbiology, Endocarditis, Bacterial diagnosis, Endocarditis, Bacterial surgery, Registries, Hospital Mortality
- Abstract
Objective: Endocarditis as a potentially life-threatening disease with high complication and mortality rates. In recent years, an increase in the incident of endocarditis has been reported throughout Europe. In the aging society, successful treatment is complex and challenging owing to the high rate of multimorbidity., Methods: We initiated a statewide prospective multicenter endocarditis registry in 2020. Perioperative risk factors, comorbidities, microbiological, laboratory and imaging diagnostics, complications, and mortality including 1-year follow-up were collected. The present midterm analysis includes factors influencing mortality in the first 313 patients., Result: In-hospital mortality and 1-year mortality were 28.4 and 40.9%, respectively. Preoperative risk factors include age ( p < 0.001), EuroSCORE II ( p < 0.001), coronary artery disease ( p = 0.022), pacemaker probe infection ( p = 0.033), preoperative left ventricular ejection fraction (LVEF), systemic inflammatory response syndrome (SIRS), pulmonary edema, heart failure, septic emboli, acute renal failure, impaired coagulation, hypalbuminemia ( p < 0.001), and N-terminal prohormone of brain natriuretic peptide (NTproBNP) ( p = 0.001). The presence of peri-annular abscess, perforation, and shunt were associated with increased mortality ( p = 0.004, 0.001, and 0.004, respectively). In addition, cardiopulmonary bypass time influenced mortality ( p = 0.002). The main postoperative causes of death were multi-organ failure, renal failure, vasoplegia, and low-output syndrome ( p < 0.001). Previous endocarditis was 7.7%, while 35.5% were prosthetic valve recipients and 33.6% were redo surgeries., Conclusion: Our first registry data show the complexity of endocarditis patients and the challenging treatment. Some risk factors can be treated preoperatively. For instance, hypalbuminemia and the duration of the procedure can be controlled with adequate albumin substitution and carefully planned procedures restricted to the essential requirements, that is, hybrid approaches with consecutive interventions., Competing Interests: None declared., (Thieme. All rights reserved.)
- Published
- 2024
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5. Everyday Cardiac Surgery in Jehovah's Witnesses of Typically Advanced Age: Clinical Outcome and Matched Comparison.
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Hartrumpf M, Kuehnel RU, Ostovar R, Schroeter F, and Albes JM
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Background and Objectives: Jehovah's Witnesses (JW) reject the transfusion of blood components based on their religious beliefs, even if they are in danger of harm or death. In cardiac surgery, this significantly reduces the margin of safety and leads to ethical conflicts. Informed consent should be carefully documented and the patient's family should be involved. This study aims to compare the postoperative course of JW who underwent major cardiac surgery with a similar population of non-Witnesses (NW)., Patients and Methods: Demographic, procedural, and postoperative data of all consecutive JW who underwent cardiac surgery at our institution were obtained from the records. They were compared with a propensity-score-matched group of NW. Anemic JW were treated with erythropoietin and/or iron as needed. Cardiac surgery was performed by experienced surgeons using median sternotomy and cardiopulmonary bypass. Common blood-sparing techniques were routinely used. Periprocedural morbidity and mortality were statistically evaluated for both groups., Results: A total of 32 JW and 64 NW were part of the matched dataset, showing no demographic or procedural differences. EPO was used preoperatively in 34.4% and postoperatively in 15.6% of JW but not in NW. Preoperative hemoglobin levels were similar (JW, 8.09 ± 0.99 mmol/L; NW, 8.18 ± 1.06; p = 0.683). JW did not receive any transfusions except for one who revoked, while NW transfusion rates were 2.5 ± 3.1 units for red cells ( p < 0.001) and 0.3 ± 0.8 for platelets ( p = 0.018). Postoperative levels differed significantly for hemoglobin (JW, 6.05 ± 1.00 mmol/L; NW, 6.88 ± 0.87; p < 0.001), and hematocrit (JW, 0.29 ± 0.04; NW, 0.33 ± 0.04; p < 0.001) but not for creatinine. Early mortality was similar (JW, 6.3%; NW, 4.7%; p = 0.745). There were more pacemakers and pneumonias in JW, while all other postoperative conditions were not different., Conclusions: Real-world data indicate that Jehovah's Witnesses can safely undergo cardiac surgery provided that patients are preconditioned and treated by experienced surgeons who use blood-saving strategies. Postoperative anemia is observed but does not translate into a worse clinical outcome. This is consistent with other studies. Finally, the results of this study suggest that all patients should benefit from optimal pretreatment and blood-sparing strategies in cardiac surgery, not just Jehovah's Witnesses.
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- 2023
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6. Results of Four-Stented Biological Aortic Valves and How They Compare to PARTNER-3.
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Rashvand J, Ostovar R, Schroeter F, Hartrumpf M, Kuehnel RU, and Albes JM
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- Humans, Male, Female, Aortic Valve diagnostic imaging, Aortic Valve surgery, Treatment Outcome, Postoperative Complications etiology, Postoperative Complications therapy, Postoperative Complications epidemiology, Risk Factors, Transcatheter Aortic Valve Replacement adverse effects, Transcatheter Aortic Valve Replacement methods, Heart Valve Prosthesis Implantation adverse effects, Heart Valve Prosthesis Implantation methods, Aortic Valve Stenosis diagnostic imaging, Aortic Valve Stenosis surgery
- Abstract
Objective: According to our nationwide registry, total numbers of surgical aortic valve implantation (sAVR) are constantly declining, while transcathether aortic valve implantation (TAVI) indications are widened toward intermediate- and low-risk patients. So, is there still room for conventionally implanted valves? Can results compete with TAVI or will sAVR be marginalized in the near future?, Methods: Between 2011 and 2019, 1,034 patients (67.1% male, mean = 72.2 years) were enrolled receiving stented biological valves with or without concomitant coronary artery bypass grafting (CABG), atrial ablation, or wrapping of the ascending aorta. Odds ratios for the early and late mortality were calculated regarding comorbidities as potential risk factors. Statistical analysis was performed using SPSS., Results: Overall, early mortality (EM) was 6.1%, 1-year mortality was 11.2%, and 5-year mortality was 19.9%. In low-risk patients (EuroSCORE II <4%), it was 1.0, 2.7, and 9.3%. Incidence of EM was significantly increased following decompensation, prosthetic valve, pacemaker carrier, dialysis, and pulmonary hypertension. Postoperative complications, such as systemic inflammatory response syndrome (SIRS), sepsis, multiorgan failure, hepatic failure, dialysis, gastrointestinal bleeding, and ileus, also increased EM. Late mortality was significantly increased by dialysis, hepatic cirrhosis, infected port system, aortic valve endocarditis, prosthetic valve carrier, and chronic hemodialysis., Conclusion: Conventionally implanted aortic valves do well early and late. The fate of the patient is dependent on individual risk-factors. Particularly, in low-risk patients, sAVR can compete with TAVI showing overall good early, as well as late results being even superior in some important aspects such as pacemaker implantation rate. Thus, the time is yet not ripe for TAVI to take over primary indications for AVR in low-risk patient., Competing Interests: None declared., (Thieme. All rights reserved.)
- Published
- 2023
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7. The Impact of Gender and Age in Obese Patients on Sternal Instability and Deep-Sternal-Wound-Healing Disorders after Median Sternotomy.
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Braun C, Schroeter F, Laux ML, Kuehnel RU, Ostovar R, Hartrumpf M, Necaev AM, Sido V, and Albes JM
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Objective: The aim of this study was to investigate the relationship between age and sex in regard to the development of deep sternal wound infections and sternal instability following median sternotomy., Methods: A propensity-score-matching analysis was conducted on 4505 patients who underwent cardiac surgery between 2009 and 2021, all of whom had a BMI of ≥30 kg/m
2 . A total of 1297 matched pairs were determined in the sex group, and 1449 matched pairs we determined in the age group. The distributions of sex, age, diabetes mellitus, delirium, unstable sterna, wire refixation, wire removal, superficial vacuum-assisted wound closure, deep vacuum-assisted wound closure, clamp time, bypass time, logistic EuroSCORE, and BMI were determined., Results: The 30-day in-hospital mortality was found to be similar in the older and younger groups (8.149% vs. 8.35%, p = 0.947), and diabetes mellitus was also equally distributed in both groups. However, postoperative delirium occurred significantly more often in the older group (29.81% vs. 17.46%, p < 0.001), and there was a significantly higher incidence in men compared with women (16.96% vs. 26.91%, p < 0.001). There were no differences found in the incidence of sternum instability, fractured sternum, superficial vacuum-assisted wound closure, and deep vacuum-assisted wound closure between the age and sex groups., Conclusions: In conclusion, this study found that sternal instability and deep-wound-healing problems occur with equal frequency in older and younger patients and in men and women following median sternotomy. However, the likelihood of postoperative delirium is significantly higher in older patients and in men. These findings suggest that a higher level of monitoring and care may be required for these high-risk patient groups to reduce the incidence of postoperative delirium and improve outcomes following median sternotomy.- Published
- 2023
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8. Endocarditis: Who Is Particularly at Risk and Why? Ten Years Analysis of Risk Factors for In-hospital Mortality in Infective Endocarditis.
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Ostovar R, Schroeter F, Erb M, Kuehnel RU, Hartrumpf M, and Albes JM
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- Male, Humans, Aged, Hospital Mortality, Retrospective Studies, Staphylococcus aureus, Treatment Outcome, Risk Factors, Prosthesis-Related Infections diagnosis, Prosthesis-Related Infections surgery, Prosthesis-Related Infections microbiology, Endocarditis, Bacterial diagnosis, Endocarditis, Bacterial surgery, Endocarditis, Bacterial microbiology, Sepsis, Heart Valve Prosthesis adverse effects, Endocarditis etiology
- Abstract
Background: Endocarditis is continuously increasing. Evidence exist that the prognosis is adversely affected by the extent of the disease. We looked at risk factors influencing in-hospital mortality (HM)., Patients and Methods: Between 2010 and 2019, 484 patients, 338 males (69.8%) with mean age of 66.1 years were operated on because of proven endocarditis. In a retrospective study, a risk factor analysis was performed., Results: Overall HM was 30.17%. Significant influencing factors (odds ratios [ORs] or p -value) for HM were: age ( p = 0.004), logistic EuroSCORE ( p < 0.001), gender (OR = 1.64), dialysis (OR = 2.64), hepatic insufficiency (OR = 2.17), reoperation (OR = 1.77), previously implanted valve (OR = 1.97), periannular abscess (OR = 9.26), sepsis on admission (OR = 12.88), and number of involved valves (OR = 1.96). Development of a sepsis and HM was significantly lower if Streptococcus mitis was the main pathogen in contrast to other bacteria ( p < 0.001). Staphylococcus aureus was significantly more often found in patients with a previously implanted prosthesis ( p = 0.03) and in recurrent endocarditis ( p = 0.02), while it significantly more often showed peripheral septic emboli than the other pathogens ( p < 0.001)., Conclusion: Endocarditis remains life-threatening. Severe comorbidities adversely affected early outcome, particularly, in presence of periannular abscesses. Patients with suspected endocarditis should be admitted to a specialized heart center as early as possible. Streptococcus mitis appears to be less virulent than S. aureus . Further studies are required to verify these findings., Competing Interests: None declared., (Thieme. All rights reserved.)
- Published
- 2023
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9. Immunosuppressive Agents and Thoracic Aortic Aneurysm: Real Correlation or Mere Coincidence?
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Ostovar R, Laux M, Kuehnel RU, Schroeter F, Braun C, Erb M, and Albes JM
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- Humans, Immunosuppressive Agents, Retrospective Studies, Treatment Outcome, Aortic Valve surgery, Aorta, Thoracic surgery, Aortic Aneurysm, Thoracic surgery, Aortic Aneurysm surgery
- Abstract
Background: Atherosclerosis, hypertension, age, and fibrillopathies are well-known risk factors for the development of aortic aneurysm. We discovered that a significant proportion of our patients were previously on chemotherapy treatment or long-term treatment with cytostatic agents or immunosuppressive drugs. Thus, we examined this phenomenon., Methods: A total of 224 patients with thoracic aorta aneurysm were retrospectively analyzed after aortic surgery from 2006 to 2016. Seventy-three patients received aortic wrapping and 151 patients underwent aortic replacement of which 89 had a valve-carrying conduit and 62 a supracoronary ascending replacement. Aortic morphology was assessed by means of compute tomography scan before and after surgery. Demographic data, risk profile, and postoperative complications were collected. Short- and long-term survival analysis was performed. Statistical analysis was performed with SPSS 19.0., Results: Eighty-eight of 224 patients undergoing aortic surgery because of aortic aneurysm had previously or currently been treated with immunosuppressive agents. Dilatation of the ascending aorta was more pronounced in patients without such therapy. Demographic profile, intraoperative, as well as short- and long-term postoperative results did not differ significantly between both groups., Conclusion: The potential effect of immunosuppressant and cytostatic therapies on the development of an aortic aneurysm needs further study. Because of the astoundingly high proportion of these patients being found in an unselected aortic aneurysm cohort with immunosuppressive therapy in the past should be monitored for potential development of aortic aneurysm. If it occurs and requires treatment these patients can fortunately be operated upon with the same short- and long-term outcome than patients without such previous therapy., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Thieme. All rights reserved.)
- Published
- 2022
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10. Do Not Withhold Mitral Surgery from Patients with Poor Left Ventricular Function.
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Ostovar R, Schmidt M, Schroeter F, Kuehnel RU, Rashvand J, Hartrumpf M, and Albes JM
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- Humans, Retrospective Studies, Stroke Volume, Treatment Outcome, Ventricular Function, Left, Mitral Valve Insufficiency surgery, Ventricular Dysfunction, Left complications, Ventricular Dysfunction, Left surgery
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Background and Objectives: Increasing reluctance to perform surgical mitral valve repair or replacement particularly in high-risk patients with poor left-ventricular function is trending. These patients are increasingly treated interventionally, e.g., by MitraClip, but often show only low to moderate improvement. The primary objective of the study was to investigate whether left ventricular ejection fraction (LVEF) influences postoperative mortality. Materials and Methods: The study included 903 patients undergoing mitral valve repair or replacement between 2009 and 2021. Statistical comparison was performed between patients with LVEF ≤ 30% and LVEF > 30%. Finally, statistical analysis was performed according to propensity score matching (1:3 PS matching). Results: No significant difference in in-hospital mortality was found before and after matching regarding LVEF ≤ 30% and LVEF > 30% (Pre: 10.8% vs. 15.1%, p = 0.241, after: 11.6% vs. 18.1%, p = 0.142). After PS matching, the 112 patients with LVEF ≤ 30% compared with 336 patients with LVEF > 30% showed a significantly higher preoperative NT-proBNP (p < 0.001), larger diameters at preoperative left ventricle and atrium (p < 0.001), lower preoperative TAPSE (p = 0.003) and PAP (p = 0.003), and more dilated cardiomyopathy and chronic kidney disease (p < 0.001, p = 0.045). Conclusions: The results of this study demonstrate that poor preoperative LVEF alone does not play a significant role in postoperative outcome and long-term mortality. Prognosis appears to be multifactorial. Poor preoperative LVEF is not a contraindication for surgery and does not justify primary interventional treatment accepting inferior hemodynamic results impeding outcome.
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- 2022
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11. How Strong Can We Pull? Critical Thresholds for Traction Forces on the Aortic Annulus: Measurements on Fresh Porcine Hearts.
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Hartrumpf M, Sterner J, Schroeter F, Kuehnel RU, Ostovar R, and Albes JM
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- Animals, Aortic Valve surgery, Polytetrafluoroethylene, Suture Techniques, Swine, Traction, Heart Valve Prosthesis, Heart Valve Prosthesis Implantation methods
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Background and Objectives: Friable or infected tissue remains a challenge in surgical aortic valve replacement. We recently described the "Caput medusae" method, in which circumferential tourniquets temporarily secure the prosthesis and are then gently knotted. Tourniquets have been shown to develop significantly less force than knots. The current study investigates the critical threshold forces for tissue damage to the aortic annulus. Materials and Methods: In 14 fresh porcine hearts, the aortic valve leaflets were removed and several pledgeted sutures were placed along the annulus at defined locations. The hearts were mounted in a self-constructed device. Incremental traction force was applied to every suture and continuously recorded. The movement of each Teflon pledget was filmed with a high-speed camera. Forces at the moment of pledget "cut-in" as well as complete "tear-out" were determined from the recordings. Results: The average threshold force was determined 9.31 ± 6.04 N for cut-in and 20.41 ± 10.02 N for tear-out. Detailed analysis showed that the right coronary region had lower threshold forces than the other regions (4.77 ± 3.28 N (range, 1.67-12.75 N) vs. 10.67 ± 6.04 N (1.62-26.00 N) for cut-in and 10.67 ± 4.04 N (5.40-18.64 N) vs. 23.33 ± 9.42 N (9.22-51.23 N) for tear-out). The findings are discussed in conjunction with the knot and tourniquet forces from our previous study. Conclusions: Even in healthy tissue, moderate forces can reach a critical level at which a Teflon pledget will cut into the annulus, while a complete tear-out is unlikely. The right coronary portion is more susceptible to damage than the remaining regions. When compared to previous data, forces during manual knotting may exceed the critical cut-in level, while rubber tourniquets may provide a higher safety margin against tissue rupture.
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- 2022
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12. Liver cirrhosis: Still an elusive risk factor in the current EuroSCORE system.
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Ostovar R, Schroeter F, Erb M, Hartrumpf M, Chopsonidou S, and Albes JM
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- Hospital Mortality, Humans, Liver Cirrhosis etiology, ROC Curve, Risk Assessment methods, Risk Factors, Cardiac Surgical Procedures adverse effects
- Abstract
Objectives: Liver cirrhosis increases the risk of death in patients having cardiac surgery, and the risk is markedly dependent on the actual stage. The EuroSCORE II, however, does not specifically address the risk of death of patients with liver cirrhosis. We investigated the predictive power of EuroSCORE II in patients with liver cirrhosis., Methods: Between 2000 and 2020, a total of 218 patients with liver cirrhosis underwent cardiac surgery. To improve the predictive value of the EuroSCORE II, we calculated additional β-coefficients to include liver cirrhosis in the EuroSCORE IIb. The control group included 5,764 patients without liver cirrhosis from the same period., Results: Of the 5,764 patients without cirrhosis, 8.9% died early. Of those with cirrhosis, 8.9% of 146 patients with Child A stage, 52.9% of 51 patients with Child B stage and 100% of 21 patients with Child C stage died. Moreover, the EuroSCORE II showed a poor predictive value for patients in Child B and C stages. The resulting values of calculated β using the area under the curve of the receiver operating characteristic and bootstrapping for Child stages as predictors of mortality were as follows: βA = 0.1640205, βB= 2.9911625 and βC= 6.2501248. By calculating the updated EuroSCORE IIb and regenerating the receiver operating characteristic curves, we were able to demonstrate an improvement in area under the curve values. Postoperative complications, need for extracorporeal membrane oxygenation or intra-aortic balloon pump implants, intensive care unit stays and hospital stays were significantly higher in cirrhotic patients with cirrhosis compared with patients without cirrhosis. The most common cause of liver cirrhosis was alcohol abuse (55.5%)., Conclusions: Although patients with liver cirrhosis represent only a small proportion of cardiac surgical cases, the poor outcomes are particularly relevant in patients with advanced stages of the disease. Our study results show that Child class A patients show outcomes similar to those of patients without liver disease whereas Child class C patients appear to be nearly inoperable, i.e. can only be operated on with exceptional risks. Including these patients in the EuroSCORE II calculation would thus represent an improvement in preoperative mortality risk assessment., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
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- 2022
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13. Reply to Nezic.
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Ostovar R, Schroeter F, and Albes JM
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- 2022
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14. Intraoperative Use of Platelet-Rich Fibrin (PRF) Reduces the Postoperative Fistula Rate After Pancreas Surgery.
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von Kirchbach A, Kuehnel RU, Juffa A, Schroeter F, Ostovar R, and Albes JM
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- Humans, Pancreas surgery, Pancreatic Fistula epidemiology, Pancreatic Fistula etiology, Pancreatic Fistula prevention & control, Postoperative Complications epidemiology, Postoperative Complications etiology, Postoperative Complications prevention & control, Retrospective Studies, Risk Factors, Pancreaticoduodenectomy adverse effects, Platelet-Rich Fibrin
- Abstract
Background: Patients undergoing pancreatic surgery are predominately very ill and therefore have a high potential for postoperative complications, which often has a life-limiting effect. As leakage of aggressive pancreatic secretions into the abdomen is one of the main reasons for an adverse outcome, measures to reduce it can be beneficial. Platelet-Rich Fibrin (PRF) is often used to seal areas that are already leaking or are susceptible to leakage at the end of the procedure. We sought to determine whether this positive intraoperative effect is associated with a positive postoperative outcome with regard to a reduction of complications., Methods: We investigated 85 patients who underwent pancreatic surgery in our surgical department. All patients were treated intraoperatively with PRF in the surgical field. The occurrence of fistulas (biochemical leakage, post-operatic pancreatic fistula (POPF) grade B and POPF grade C). We compared our clinical data with patient data from the literature., Results: The production of PRF from the patient's own blood is simple, safe, and not stressful for the patient. Complications related to production or use were not observed. Our patient group showed a lower fistula rate compared to those patient groups in the literature (POPF grade B and C: <13% vs. 16-72%)., Conclusion: The results showed that use of PRF had a beneficial effect in patients undergoing pancreatic surgery, as reflected by a reduction in postsurgical fistula formation and better outcomes.
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- 2022
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15. Degeneration of the lumbar spine and its relation to the expression of collagen and elastin in facet joint capsules and ligament flavum.
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Voelker A, Schroeter F, Steinke H, and Heyde CE
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- Aged, 80 and over, Cadaver, Collagen, Collagen Type I, Elastin, Female, Humans, Joint Capsule, Lumbar Vertebrae, Male, Middle Aged, Intervertebral Disc Degeneration, Ligamentum Flavum, Zygapophyseal Joint
- Abstract
Objective: The aim of the study was to assess the relationship between the expression of elastin, collagen type I, II,III and the degenera- tion of the facet joint capsule and the ligamentum flavum., Methods: 10 patients (4 male, 6 female) (mean age 61 ± 14,9) undergoing surgery for degenerative lumbar spine syndrome and 5 cadav- ers (3 male, 2 female) (age of death 87 ± 8,6 years) were included in this study. One set of tissue samples was taken from each patient in the patient group intraoperatively and two sets of samples were taken from each cadaver in the cadaver group posthumosly from the ligamentum flavum (medial and lateral) and from the facet joint capsules (superior and inferior articular process) at the L4/5 segment. Western blot analysis was performed for collagen types I, II, III and for elastin. Disc degeneration was scored according to the Pfirmann Classification, facet joint arthrosis was scored according to the Fujiwara Classification and their relationship with protein expression was investigated., Results: There was a strong expression of Collagen type I in the patient group (PG) compared to the body donor group (BDG) in the facet joint capsule (FJC) and in the lateral samples of the ligamentum flavum. Samples of the FJC showed lower expression of elastin in the PG compared with the BDG, but without statistical significance. An increased expression of collagen type I compared to elastin in the PG could be shown. In contrast, elastin predominated in the samples of the BDG group compared to collagen type I (collagen type I/ elastin PG: PAsup 2,78; PAinf 2,61; LFmed 2,23; 225 LFlat 1,83; BDG: PAsup 0,15; PAinf 0,2; LFmed 0,2; LFlat 0,27). Rank correlation coefficient according to Spearman showed low to moderate correlations for collagen type I, III and elastin for the degree of disc degeneration accord- ing to Pfirrmann and the degree of facet joint osteoarthritis according to Fujiwara, all of them without statistical significance., Conclusion: This study has shown us that in the context of degenerative changes of the lumbar spine, there is an increased expression of collagen type I and a dominance over elastin., Level of Evidence: Level III, Diagnostic Study.
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- 2022
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16. Platelet-Rich Fibrin in Combination with Local Antibiotics Optimizes Wound Healing After Deep Sternal Wound Problems and Prevents Reinfection.
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Kuehnel RU, Schroeter F, Mueller T, Ostovar R, and Albes JM
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- Anti-Bacterial Agents therapeutic use, Humans, Reinfection, Surgical Wound Infection drug therapy, Surgical Wound Infection prevention & control, Wound Healing, Platelet-Rich Fibrin
- Abstract
Objective: Disturbed wound healing is a significant problem in patients after cardiac surgery. Problems with deep sternal wound healing are rare, but can be quite difficult to treat. Furthermore, the therapy is highly expensive and consumes many of the patient's personal resources. Another major obstacle in this patient group is reinfection after secondary wound closure. We examined how to prevent early reinfection through the use of growth factors in combination with local antibiotics., Methods: Our study included 232 patients with a deep sternal wound healing problem. After initial vacuum therapy, we planned secondary wound closure. During wound closure, we used only platelet-rich fibrin in a PRF group (109 patients). In another group (123 patients), we covered the wounds intraoperatively with a combination of PRF and local antibiotics (PRF CoDelivery). All patients were observed for 30 days for signs of early surgical site infection., Results: After 30 days, 22 patients (20.2%) in the PRF group showed a persistent problem with wound healing with or without reinfection. In contrast, only 12 patients (9.8%) in the PRF CoDelivery group had this problem (p=0.023 PRF vs. PRF CoDelivery)., Conclusion: The combination of growth factors and antibiotics was associated with a significantly reduced incidence of early reinfection and thus can be expected to have a positive impact on wound healing in complicated scenarios. Furthermore, the combination of PRF and local antibiotics was easy to use. Further studies are needed to verify these initial findings.
- Published
- 2021
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17. MitraClip: a word of caution regarding an all too liberal indication and delayed referral to surgery in case of failure.
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Ostovar R, Erb M, Schroeter F, Zytowski M, Kuehnel RU, Hartrumpf M, and Albes JM
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- Aged, Humans, Mitral Valve diagnostic imaging, Mitral Valve surgery, Referral and Consultation, Retrospective Studies, Treatment Outcome, Heart Valve Prosthesis adverse effects, Heart Valve Prosthesis Implantation adverse effects, Mitral Valve Insufficiency diagnostic imaging, Mitral Valve Insufficiency surgery
- Abstract
Objectives: Although indications for the MitraClip are becoming increasingly liberal, the number of patients requiring valve surgery after an insufficient outcome of the procedure is growing. Referral to surgery is, however, frequently delayed. During this time, the patients often deteriorate. We retrospectively analysed patients before MitraClip implantation and after mitral valve surgery., Methods: A total of 49 patients who received a mitral valve replacement (average 8 ± 12 months after MitraClip implantation) were assessed. Of these, 53% had 2-4 clips inserted. The mean age was 73 years, and the mean log EuroSCORE was 20.79 ± 14.42%. Echocardiographic data obtained prior to MitraClip implantation and preoperatively, 10 days and 6 and 12 months after cardiac surgery were reviewed. Survival analysis, risk profile and postoperative complications were analysed., Results: The 30-day and 1-year mortality was 26.5% and 59.2%, respectively. Prior to MitraClip implantation, 42.8% of patients had mild tricuspid insufficiency and 6.1% had moderate tricuspid insufficiency. Prior to surgery, 26.5% showed mild, 32.7% moderate and 38.8% severe tricuspid insufficiency (P < 0.001). Furthermore, right heart function assessed by tricuspid annular plane systolic excursion deteriorated significantly after Implantation of the MitraClip (P < 0.001). In patients with a MitraClip, the pulmonary artery pressure was significantly higher at the time of mitral replacement than it was before the MitraClip was implanted (P < 0.001)., Conclusions: A subgroup of patients does not benefit from a MitraClip and shows progressive deterioration in cardiac function, making valve replacement under difficult circumstances inevitable. The earlier these patients are operated on, the better it is. It can be assumed that some patients would be better off with primary surgery, especially if mitral reconstruction is then still feasible. Therefore, the indications for MitraClip implantation should be carefully considered and caution should be exercised during monitoring., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2021
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18. Clinical Short-Term Outcome and Hemodynamic Comparison of Six Contemporary Bovine Aortic Valve Prostheses.
- Author
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Hartrumpf M, Kuehnel RU, Schroeter F, Haase R, Laux ML, Ostovar R, and Albes JM
- Subjects
- Aged, Animals, Aortic Valve diagnostic imaging, Aortic Valve physiopathology, Aortic Valve Stenosis diagnostic imaging, Aortic Valve Stenosis mortality, Aortic Valve Stenosis physiopathology, Cattle, Female, Heart Valve Prosthesis Implantation adverse effects, Heart Valve Prosthesis Implantation mortality, Humans, Male, Middle Aged, Postoperative Complications mortality, Postoperative Complications therapy, Prosthesis Design, Retrospective Studies, Risk Factors, Treatment Outcome, Aortic Valve surgery, Aortic Valve Stenosis surgery, Bioprosthesis, Heart Valve Prosthesis, Heart Valve Prosthesis Implantation instrumentation, Hemodynamics
- Abstract
Background: Conventional stented valves (CV) remain gold standard for aortic valve disease. Bovine prostheses have been improved and rapid deployment valves (RDV) have arrived in the recent decade. We compare clinical and hemodynamic short-term outcome of six bovine valves., Methods: We retrospectively evaluated 829 consecutive patients (all-comers) receiving bovine aortic valve replacement (AVR). Four CV from different manufacturers (Mitroflow, Crown, Perimount, Trifecta) and two RDV (Perceval, Intuity) were compared in terms of pre-, intra-, and postprocedural data. A risk model for mortality was created., Results: All valves reduced gradients. From 23 mm, all CV showed acceptable gradients. Twenty-one millimeter Mitroflow/Perceval and 19 mm Crown showed above-average gradients. As baseline data differed, we performed propensity matching between aggregated isolated CV and RDV groups. Cardiopulmonary bypass (CPB), clamp, and surgery times were shorter with RDV (87.4 ± 34.0 min vs 111.0 ± 34.2, 54.3 ± 21.1 vs 74.9 ± 20.4, 155.2 ± 42.9 vs 178.0 ± 46.8, p < 0.001). New pacemaker rate (10.1 vs 1.3%, p = 0.016) and the tendency toward neurologic events (8.9 vs 2.5%, p = 0.086) were higher using RDV, induced mainly by the Perceval. Early mortality was equal (2.5 vs 1.3%, p = 0.560). Revision for bleeding, dialysis, blood products, length-of-stay, gradients, and regurgitation was also equal. Risk analysis showed that low valve size, low ejection fraction, endocarditis, administration of red cells, and prolonged CPB time were predictors of elevated mortality., Conclusion: Isolated bovine AVR has low mortality. Valves ≥ 23 mm show comparable gradients while the valve model matters < 23 mm. RDV should be used with care. Procedure-related times are shorter than those of CV but pacemaker implantation and neurologic events are more frequent (Perceval). Early mortality is low and valve performance comparable to CV., Competing Interests: None., (Thieme. All rights reserved.)
- Published
- 2020
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19. Tourniquet fixing prior to knot tying reduces forces during aortic valve replacement: experimental results from 18 surgeons.
- Author
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Hartrumpf M, Sterner J, Schroeter F, Kuehnel RU, Laux ML, Braun C, and Albes JM
- Subjects
- Humans, Prosthesis Design, Aortic Valve surgery, Heart Valve Diseases surgery, Heart Valve Prosthesis, Surgeons statistics & numerical data, Suture Techniques instrumentation, Sutures, Tourniquets
- Abstract
Objectives: To increase the safety of aortic valve replacement, we developed the 'Caput medusae' method, where the prosthesis is prefixed with circumferential tourniquets prior to knot tying. We assumed that an even distribution of forces may help reduce tissue damage. To confirm this theoretically, we compared forces between knots and tourniquets., Methods: The experimental set-up included a device with movable acrylic plates, a mounted valve and a set of sutures. Traction forces were measured with a luggage scale. Two different tourniquets were compared individually and as bundles of 15. Force-path curves were generated. Knotting and tourniquet forces of 18 staff surgeons were then compared. Both modalities were measured 10 times on 2 days, resulting in 40 observations per surgeon, or 360 observations per modality., Results: Polyvinyl chloride tourniquets were stiffer than silicone, expressed by a 1.5- to 1.7-fold higher regression-line slope. Fifteen simultaneous tubes produced force increments 7.9-8.9 times higher than their single counterparts. Overall knotting force was 13.64 ± 5.76 vs tourniquet 1.08 ± 0.48 N. Male surgeons' knotting forces were higher compared to female staff (14.76 ± 6.01 vs 10.73 ± 3.74 N; P < 0.001) while tourniquet forces did not differ (1.09 ± 0.47 vs 1.05 ± 0.49 N; P = 0.459). Dedicated valve surgeons (n = 10) tightened the tourniquets more strongly than inexperienced surgeons (1.20 ± 0.52 vs 0.94 ± 0.37 N; P < 0.001); knotting was similar. Multivariable analysis confirmed only valve experience as a predictor of tourniquet strength (experienced surgeons exerted higher force)., Conclusions: Tourniquets exert less force on the tissue than knots. When distributed over the circumference, they can reduce local tension and avoid potential paravalvular leakage. Complete or partial use of tourniquets may thus be an additional option to enhance surgical safety., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2020
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20. Endocarditis: An Ever Increasing Problem in Cardiac Surgery.
- Author
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Ostovar R, Schroeter F, Kuehnel RU, Erb M, Filip T, Claus T, and Albes JM
- Subjects
- Adult, Aged, Aged, 80 and over, Antibiotic Prophylaxis, Catheter-Related Infections diagnosis, Catheter-Related Infections microbiology, Catheter-Related Infections mortality, Defibrillators, Implantable adverse effects, Drug Resistance, Multiple, Bacterial, Endocarditis, Bacterial diagnosis, Endocarditis, Bacterial microbiology, Endocarditis, Bacterial mortality, Female, Heart Valve Prosthesis adverse effects, Humans, Male, Middle Aged, Pacemaker, Artificial adverse effects, Prosthesis-Related Infections diagnosis, Prosthesis-Related Infections microbiology, Prosthesis-Related Infections mortality, Reoperation, Retrospective Studies, Risk Assessment, Risk Factors, Time Factors, Treatment Outcome, Cardiac Surgical Procedures adverse effects, Cardiac Surgical Procedures mortality, Catheter-Related Infections surgery, Endocarditis, Bacterial surgery, Prosthesis-Related Infections surgery
- Abstract
Background: Endocarditis remains one of the most threatening diagnoses in cardiac surgery and is still increasing. Particularly, device-related as well as prosthetic endocarditis appears to be on the rise. Early mortality and periprocedural complications are high jeopardizing the success of surgical efforts. We looked at the development of the numbers and the distribution of endocarditis in an all-comer analysis., Methods: From 2003 to 2017, 752 patients with endocarditis were transferred to our cardiosurgical institution (mean age 65 ± 13 years; mean logistic EuroSCORE 28.01%; males 74.33%). A total of 89.49% of them were surgically treated; 30.01% redo cases thereof; and 9.17% had been operated previously for acute endocarditis., Results: While the total number of cardiosurgical procedures remained relatively stable throughout the years, 20 patients were admitted in 2003 and 79 in 2017 yielding more than fourfold increase ( p < 0.001). Early mortality of all patients was 25.1%. Septic emboli occurred in 23.7% and 43.8% cerebral emboli thereof. A significant increase of aortic, mitral, and tricuspid valves involvement was observed ( p < 0.001). An increase of device-related endocarditis was also noted ( p < 0.001)., Conclusion: Endocarditis remains a serious problem with high early mortality and morbidity. The vast increase of electrophysiological device implantations has resulted in an increase of tricuspid valve involvement. Liberalization of endocarditis prophylaxis, that is, more restrictive use of antibiotics in 2007 may have at least partially contributed to an increase of the individual risk to suffer from acute endocarditis. A renaissance of a stricter endocarditis-prophylaxis may thus be considered., Competing Interests: None declared., (Georg Thieme Verlag KG Stuttgart · New York.)
- Published
- 2019
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21. In vitro supplementation with unsaturated fatty acids improves boar sperm viability after storage at 6 °C.
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Jakop U, Svetlichnyy V, Schiller J, Schulze M, Schroeter F, and Mueller K
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- Animals, Cold Temperature, In Vitro Techniques, Male, Spermatozoa drug effects, Spermatozoa physiology, Swine, Cryopreservation veterinary, Dietary Supplements, Fatty Acids, Unsaturated pharmacology, Semen Preservation veterinary, Spermatozoa cytology
- Abstract
Liquid preservation of the cold-sensitive boar sperm at a lesser temperature than the standard 17 °C would reduce bacterial growth and minimize the use of antibiotics. There was assessment, therefore, of the capacity of individual fatty acids bound to fatty acid free BSA to improve sperm survival at 6 °C because oxidative stress and lipid degradation are prominent detrimental factors. Different effects of the fatty acids were observed. Supplementation with naturally occurring fatty acids (linolenic, linoleic, oleic, palmitoleic acid), which may become metabolically incorporated into sperm lipids, increased the number of motile and progressively motile sperm after 2 days of storage during a thermo-resistance test (5 h at 38 °C) to that of control samples preserved at 17 °C in pure Beltsville Thawing Solution. With the exception of linolenic acid, all naturally occurring fatty acids enhanced the number of sperm with active mitochondria after 3 days of storage. Palmitoleic acid was the most effective supplement with effects already present when sperm were re-warmed for 30 min after 2 and 7 days of storage. The non-endogenous, non-integrated timnodonic acid (20:5) had no effect on sperm variables. Because the application of individual fatty acids attached to BSA had differing effects in preserving boar sperm at 6 °C, the use of combinations of fatty acids could be more efficacious than with use of natural lipid supplements for low temperature preservation of sperm., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2019
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22. Q-PULS, a new quasi-physiological pulsatile extracorporeal model to simulate heart function.
- Author
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Ostovar R, Hartrumpf M, Kuehnel RU, Schroeter F, Laux M, Erb M, Claus T, and Albes JM
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- Animals, Diastole, Disease Models, Animal, Mitral Valve Insufficiency physiopathology, Swine, Systole, Cardiac Output physiology, Extracorporeal Circulation methods, Heart Ventricles physiopathology, Mitral Valve Insufficiency surgery, Pulsatile Flow physiology
- Abstract
Objectives: The invention of new surgical procedures requires testing at different stages including animal models. To facilitate this process, we have developed a computer-controlled extracorporeal circulation system for testing of an explanted porcine heart simulating a variety of physiological parameters. Mitral valve function can be assessed before and after induced valve insufficiency and after valve repair. Accordingly, techniques and instruments can be modified at early stages of prototype development., Methods: In the diastole, the left atrium is passively filled through the reservoir. The loading pressure of the atrium and flow rates can be widely adjusted. To simulate the systole, a linear motor-driven piston pump promotes volume into the left ventricle and the aorta. An additional circulatory pump compensates for undesired total emptying of the heart chambers. The processor control of the linear pump allows for various settings of flow rate, velocity and even irregular rhythm. Twenty-one isolated porcine hearts were used. The leaflet movement was filmed using a universal serial bus (USB)-probe camera., Results: With 80 mm stroke and 1 m/s speed, a volume of 150 ml can be pumped at a heart rate of up to 73 bpm. Cardiac outputs of up to 10.9 l/min can be achieved. Constant visualization and continuous measurements of the pressure gradients before and after the induction of mitral insufficiency and after repair allowed quantitative verification of repair quality under beating-heart conditions., Conclusions: This model allows a controllable pulsation, loading and unloading of a porcine heart in a wide range. Thus, the function of the leaflets and repair results can be qualitatively and quantitatively evaluated under quasiphysiological conditions., (© The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2019
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23. Tailored Palladate Tunable Aryl Alkyl Ionic Liquids (TAAILs).
- Author
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Schroeter F, Soellner J, and Strassner T
- Abstract
We present a new class of tunable aryl alkyl ionic liquids (TAAILs) containing different palladate counter ions. Solid-state structures for representative compounds have been obtained. Their properties are presented in comparison to those of newly synthesized and reported palladate ionic liquids with conventional counter ions. It was found that the aryl substitution pattern and the type of anion have a profound influence on the melting point. The speciation of the different anions in solution has been rationalized by DFT calculations., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2019
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24. Electron-poor hemilabile dicationic palladium NHC complexes - synthesis, structure and catalytic activity.
- Author
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Schroeter F, Císařová I, Soellner J, Herdtweck E, and Strassner T
- Abstract
We present a new class of dicationic palladium NHC complexes with two carbene ligands bearing different aryl substituents and a hemilabile pyrimidyl group. They can either be synthesized from the imidazolium salts via the silver transmetalation route to a halide-free palladium(ii) precursor or by direct deprotonation by palladium acetate. For four complexes we could determine their solid-state structures by X-ray diffraction experiments. Insight gained by NMR spectroscopy and DFT calculations revealed that in solution the two potentially bidentate ligands interchange between chelating and non-chelating coordination modes. The preference of these coordination modes is governed by the steric influence of the different ligands. The complexes were shown to be active catalysts for the hydroarylation of alkynes, and their performance was rationalized by DFT calculations.
- Published
- 2018
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25. Cobalt-Catalyzed Hydroarylations and Hydroaminations of Alkenes in Tunable Aryl Alkyl Ionic Liquids.
- Author
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Schroeter F, Lerch S, Kaliner M, and Strassner T
- Abstract
Tunable aryl alkyl ionic liquids (TAAILs) are a promising class of imidazolium- or triazolium-based ionic liquids. Contrary to "standard" all-alkyl ionic liquids, these carry an aryl ring together with a linear or branched alkyl chain. Their application in the cobalt-catalyzed hydroarylation/hydroamination of alkenes and anilines is presented. The catalytic system is tolerant toward air and is scalable and reusable. It has been successfully used for the synthesis of pharmacologically relevant primary to tertiary aryl amines.
- Published
- 2018
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26. Understanding Anionic "Ligandless" Palladium Species in the Mizoroki-Heck Reaction.
- Author
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Schroeter F and Strassner T
- Abstract
The anionic complex [NBu
4 ][Pd(DMSO)Cl3 ], as a "ligandless" system, was shown to be an active catalyst in the Mizoroki-Heck coupling of aryl chlorides in the absence of strongly σ-donating ligands. To investigate the experimentally observed influence of halides and the amount of water on the catalytic activity, we employed a combination of experiments and theoretical calculations. The presence of water was shown to be critical for the formation of the active palladium(0) species by oxidation of in situ generated tributylamine. Oxidative addition to an anionic palladium(0) species was found to be the rate-determining step of the catalytic cycle. For the ensuing steps, both neutral and anionic pathways were considered. It was shown that, in the absence of strongly σ-donating neutral ligands, chloride ions stabilize the catalytic intermediates. Therefore, an anionic pathway is preferred, which explains the need for tetrabutylammonium chloride as an additive. The study of the influence of bromide ions on the catalytic activity revealed that the strongly exergonic displacement of the neutral substrates by bromide ions lowers the catalytic activity.- Published
- 2018
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