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Dive into the research topics where Andreas Schaefer is active.

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Featured researches published by Andreas Schaefer.


Thoracic and Cardiovascular Surgeon | 2015

Valve-in-Valve Procedures in Failing Biological Xenografts Using a Novel Balloon-Expandable Device: Experience in Aortic, Mitral, and Tricuspid Positions.

Andreas Schaefer; Lenard Conradi; Moritz Seiffert; Edith Lubos; Stefan Blankenberg; Hermann Reichenspurner; Ulrich Schaefer; Hendrik Treede

Background Valve-in-valve (ViV) procedures for degenerated bioprostheses are an alternative for the standard of care in an aging population. Several reports showed that the Edwards Sapien XT (Edwards Lifesciences Co., Irvine, California, United States) transcatheter heart valve (THV) can be used in aortic, mitral, and tricuspid position for ViV procedures. No published case series for different valve positions exist regarding suitability of the new Edwards Sapien 3 (Edwards Lifesciences Co.) THV for this purpose. Especially, the increased stent height compared with the XT and the newly added polyethylene terephthalate cuff is of potential concern in ViV interventions. Herein, we report six cases of ViV procedures with the Edwards Sapien 3 THV with a focus on technical considerations. Methods and Results Between October 2013 and November 2014, six ViV procedures with the Edwards Sapien 3 THV were performed. Four implants were done in aortic, one in mitral, and one in tricuspid position. All procedures were performed successfully without any complications. Fluoroscopy and echocardiography confirmed an adequate position and function without any paravalvular or transvalvular leakage or elevated transvalvular gradients in any case. Conclusion Preliminary experience suggests, ViV procedures with the Edwards Sapien 3 THV are safe and reliable. The outer polyethylene terephthalate cuff, for enhanced paravalvular sealing, led to a good outcome, concerning PVL in ViV procedures without resulting in elevated transvalvular gradients. This was even the case in a mildly undersized THV when compared with the internal diameter of the surgical bioprosthesis. The central radiopaque positioning marker and the fine adjustment wheel allow for accurate positioning within degenerated bioprostheses. The increased stent height, compared with the Sapien XT, led to no complications, especially in mitral position. In bioprostheses without any fluoroscopic landmarks, a balloon valvuloplasty may be necessary to identify the appropriate deployment position.


Asaio Journal | 2015

Concomitant minimally invasive HVAD and transapical aortic valve implantation.

Andreas Schaefer; Hendrik Treede; A. Bernhardt; Florian Wagner; Hermann Reichenspurner; T. Deuse

Minimally invasive left ventricular assist device (LVAD) implantation with the HeartWare VAD (HVAD) has been reported lately as an alternative approach to median sternotomy due to its favorable results regarding sternal wound complications, mediastinitis, postoperative bleeding, and right ventricular failure (RVF). Relevant aortic regurgitation is a cardiac comorbidity that requires surgical repair at the time of LVAD implantation to reduce recirculation and ensure adequate forward flow. We herein report on a patient with severely reduced left ventricular function due to ischemic cardiomyopathy, moderate aortic regurgitation, and a reduced right ventricular function. We performed minimally invasive HVAD implantation with concomitant transapical transcatheter aortic valve replacement. We believe this hybrid procedure could potentially reduce the risk for post-LVAD RVF because it preserves the pericardial geometry and obviates the need for cardioplegic arrest.


European Journal of Cardio-Thoracic Surgery | 2017

The value of fluorine-18 deoxyglucose positron emission tomography scans in patients with ventricular assist device specific infections†

A. Bernhardt; Mustafa A Pamirsad; Chantal Brand; Daniel Reichart; Milena Tienken; Markus J. Barten; Andreas Schaefer; Hanno Grahn; Meike Rybczynski; T. Deuse; Hermann Reichenspurner; Florian Wagner

BACKGROUND Infections are major complications in patients with ventricular assist devices (VAD). Positron emission tomography with deoxyglucose marked by fluorine-18 ( 18 F-FDG PET/CT) is a diagnostic tool to scan for tissue with high metabolism as present in infections. The specificity of 18 F-FDG PET/CT to discriminate between infection and an aseptic reaction of the implanted device is not defined and its evaluation is the aim of this retrospective analysis. METHODS Until September 2015 a total of 100 patients underwent VAD implantations in our institution. Twenty-one patients (mean age 53.7 ± 14.3 years) had 29 PET-CT examinations for a suspected infection. All radiology reports were compared to clinical and intraoperative parameters. Infections were reported according to the guidelines of the International Society of Heart and Lung Transplantation. Follow-up was 222 days (range 107-484 days) after PET-CT scans and was complete in all patients. RESULTS In 7 patients PET-CT scan ruled out any VAD associated infection. Sixteen patients had a VAD specific infection. Two patients had false negative PET-CT scan results. The sensitivity of VAD-specific infections was 87.5%, the specificity 100%, the positive predictive value was 100% and the negative predictive value 86.7%. Seven patients had more than one PET-CT scans at different time points. CONCLUSIONS PET-CT scan findings showed a high specificity and positive predictive value for VAD-specific infections. Therefore, it may have the potential to guide the clinician in handling patients with infectious complications after VAD implantation.


Asaio Journal | 2017

Outcomes of Minimally Invasive Temporary Right Ventricular Assist Device Support for Acute Right Ventricular Failure During Minimally Invasive Left Ventricular Assist Device Implantation

Andreas Schaefer; Daniel Reichart; A. Bernhardt; Mathias Kubik; Markus J. Barten; Florian Wagner; Hermann Reichenspurner; Sebastian A. Philipp; T. Deuse

Right ventricular failure (RVF) may still occur despite the benefits of minimally invasive left ventricular assist device (MI-LVAD) implantation. Our center strategy aims to avoid aggressive postoperative inotrope use by using mechanical support to facilitate right ventricle recovery and adaptation. We herein report first outcomes of patients with minimally invasive temporary right ventricular assist device (MI-t-RVAD) support for RVF during MI-LVAD implantation. Right ventricular failure was defined as requiring more than moderate inotopic support after weaning from cardiopulmonary bypass according to Interagency Registry for Mechanically Assisted Circulatory Support adverse event definitions. All patients requiring MI-t-RVAD support for RVF during MI-LVAD implantation between January, 2012 and April, 2016 were retrospectively reviewed. Clinical endpoints were death or unsuccessful RVAD weaning. Overall 10 patients (90% male, mean age 49.6 ± 14.8 years) underwent MI-t-RVAD implantation. Duration of MI-t-RVAD support was 16.2 ± 11.6 days. Right ventricular assist device weaning and subsequent uneventful awake device explantation was successful in all cases. The 30 day survival was 80%. Our results confirm safety and feasibility of MI-t-RVAD support for acute RVF in the setting of MI-LVAD implantation. The potential benefits of this strategy are more stable hemodynamics in the first postoperative days that usually are crucial for LVAD patients and reduced inotrope requirement.


Basic & Clinical Pharmacology & Toxicology | 2016

Pharmacokinetics of the Experimental Non-Nucleosidic DNA Methyl Transferase Inhibitor N-Phthalyl-L-Tryptophan (RG 108) in Rats.

Yvonne Schneeberger; Justus Stenzig; Florian Hübner; Andreas Schaefer; Hermann Reichenspurner; Thomas Eschenhagen

DNA methyl transferase (DNMT) inhibitors can re‐establish the expression of tumour suppressor genes in malignant diseases, but might also be useful in other diseases. Inhibitors in clinical use are nucleosidic cytotoxic agents that need to be integrated into the DNA of dividing cells. Here, we assessed the in vivo kinetics of a non‐nucleosidic inhibitor that is potentially free of cytotoxic effects and does not require cell division. The non‐specific DNMT inhibitor N‐phthalyl‐l‐tryptophan (RG 108) was injected subcutaneously in rats. Blood was drawn 0, 0.5, 1, 2, 4, 6, 8 and 24 hr after injection and RG 108 in plasma was measured by high‐performance liquid chromatography coupled to mass spectrometry. Trough levels and area under the curve (AUC) were significantly higher with multiple‐dose administration and cytochrome inhibition. In this group, time to maximal plasma concentration (tmax, mean ± S.D.) was 37.5 ± 15 min., terminal plasma half‐life was approximately 3.7 h (60% CI: 2.1–15.6 h), maximal plasma concentration (Cmax) was 61.3 ± 7.6 μM, and AUC was 200 ± 54 μmol·h/l. RG 108 peak levels were not influenced by cytochrome inhibition or multiple‐dose administration regimens. Maximal tissue levels (Cmax in μmol/kg) were 6.9 ± 6.7, 1.6 ± 0.4 and 3.4 ± 1.1 in liver, skeletal and heart muscle, respectively. We conclude that despite its high lipophilicity, RG 108 can be used for in vivo experiments, appears safe and yields plasma and tissue levels in the range of the described 50% inhibitory concentration of around 1 to 5 μM. RG 108 can therefore be a useful tool for in vivo DNMT inhibition.


Journal of Cardiothoracic Surgery | 2015

Failing stentless Bioprostheses in patients with carcinoid heart valve disease.

Andreas Schaefer; Bjoern Sill; Jeannette Schoenebeck; Yvonne Schneeberger; Hermann Reichenspurner; Helmut Gulbins

BackgroundCarcinoid tumor with consecutive endocardial fibroelastosis of the right heart, known as carcinoid heart valve disease (CHVD) or Hedinger’s syndrome, is accompanied by combined right-sided valvular dysfunction with regurgitation and stenosis of the affected valves. Cardiac surgery with replacement of the tricuspid and/or pulmonary valve is an established therapeutic option for patients with Hedinger’s syndrome. Little is known about the long term outcome and the choice of prosthesis for the pulmonal position is still a matter of debate.MethodsThe authors report three cases of pulmonary valve replacement with stentless bioprostheses (Medtronic Freestyle®, Medtronic PLC, Minneapolis, MN, USA) due to severe pulmonary valve degeneration in consequence of Hedinger’s syndrome.ResultsAll patients presented with re-stenosis of the pulmonal valve conduit at the height of the anastomoses in a premature fashion. Due to the increased risk for repeat surgical valve replacement, two patients were treated by transcatheter heart valves.ConclusionWe do not recommend the replacement of the pulmonary valve with stentless bioprostheses in patients with CHVD. These valves presented with an extreme premature degeneration and consecutive re-stenosis and heart failure.


Interactive Cardiovascular and Thoracic Surgery | 2016

Minimally invasive endoscopic surgery versus catheter-based device occlusion for atrial septal defects in adults: reconsideration of the standard of care

Yvonne Schneeberger; Andreas Schaefer; Lenard Conradi; J. Brickwedel; Hermann Reichenspurner; Rainer Kozlik-Feldmann; Christian Detter

Objectives Percutaneous ostium secundum atrial septal defect (ASD II) closure has become the standard of care for treatment of congenital ASD II in adults. Nevertheless, patients are frequently ineligible for this technique due to challenging morphology. In such cases, closure via minimally invasive cardiac surgery (MICS) is an appropriate treatment option. The aim of this study is to compare outcomes of MICS and use of a percutaneous Amplatzer septal occluder (ASO) device for treatment of ASD II in adults. Methods From July 2002 to June 2014, 95 patients underwent MICS for congenital ASD II closure. During the same period, 169 patients underwent ASO procedure. Outcomes in terms of remaining ASD II, new onset atrial fibrillation (AF), post-interventional stroke, myocardial infarction and the post procedural implementation of anticoagulation were compared. Results Apart from age (38.3 ± 12.7 vs 49.6 ± 15.7 years, P  < 0.0001) the groups did not differ in baseline characteristics. A significantly higher rate of residual ASD II was found in the ASO group at 3 months (0% vs 30.8%, P  < 0.0001), 6 months (0% vs 15.9%, P  < 0.0001) and 12 months follow-up (0% vs 7.1%, P  = 0.005). A significantly higher rate of new-onset AF was seen in the ASO group (0% vs 9.5%, P  = 0.0008). Conclusions MICS for ASD II is a safe and reproducible procedure with 0% mortality in our cohort. More complete closure of ASD, decreased rates of new onset AF and decreased need for oral anticoagulation are the advantages of the MICS procedure. Compared with the current standard of care, the MICS approach is feasible regardless of ASD morphology.


Interactive Cardiovascular and Thoracic Surgery | 2016

Preoperative Ticagrelor administration leads to a higher risk of bleeding during and after coronary bypass surgery in a case-matched analysis

Andreas Schaefer; Bjoern Sill; Jeannette Schoenebeck; Yvonne Schneeberger; Mathias Kubik; Hermann Reichenspurner; Helmut Gulbins

OBJECTIVES To evaluate the effect of Ticagrelor on intra- and postoperative bleeding complications in patients undergoing coronary bypass surgery. METHODS For this study, patients who underwent on-pump or off-pump coronary bypass surgery with preoperative acetylsalicylic acid (ASA) and Ticagrelor administration, between January 2014 and December 2014, were included. In the matched control group, continued dual antiplatelet therapy (DAPT) consisted of Clopidogrel and ASA. A total of 28 consecutive patients (24 males; 73 ± 6.6 years) with preoperative Ticagrelor intake underwent elective (n = 22), urgent (n = 2) or emergency (n = 4) cardiac bypass surgery. The postoperative blood loss, red blood cell units given and intra- and postoperative bleeding complications were documented. To evaluate the effect of Ticagrelor treatment on bleeding during and after coronary bypass surgery in a non-randomized study, we used a case-matched analysis. RESULTS Baseline parameters showed no important differences between the study group and the control group regarding the matching variables, left ventricular function, preoperative clinical status and risk stratification. The preoperative laboratory analysis showed no important differences regarding coagulation and blood cell count parameters. Overall blood loss was significantly higher in the study group with a mean loss of 1028.8 ± 735.5 ml (P = 0.0002). Accordingly, units of red blood cells administered were also significantly higher in the study group (P = 0.0002). In the Ticagrelor group, there were six rethoracotomies due to postoperative bleeding with a blood loss of more than 1200 ml in the first 3 h. With no rethoracotomies in the Clopidogrel group, this also showed statistical significance for the postoperative course (P = 0.02). There were no differences found regarding ICU stay and ventilation time. Comparing the mean hospital stay, the study group presented a significantly longer stay than the control group (P = 0.001). CONCLUSIONS Recent studies about bleeding complications in patients with Ticagrelor intake undergoing CABG in a real-life scenario presented inconsistent data. We were able to show in a case-matched analysis that Ticagrelor administration leads to significantly higher blood loss, more red blood cell units transfused and a higher rate of rethoracotomies. The data also present a longer hospital stay to the disadvantage of the study group. Consequently, Ticagrelor intake before CABG procedures should be avoided or at least discontinued 3 days before cardiac surgery.


JACC: Basic to Translational Science | 2018

Apolipoprotein A-I Reduces In-Stent Restenosis and Platelet Activation and Alters Neointimal Cellular Phenotype

Laura Z. Vanags; Joanne T. M. Tan; Keyvan Karimi Galougahi; Andreas Schaefer; Steven G. Wise; Andrew Murphy; Ziad Ali; Christina A. Bursill

Visual Abstract


Thoracic and Cardiovascular Surgeon | 2018

Analysis of Minimally Invasive Left Thoracotomy HVAD Implantation – A Single-Center Experience

Daniel Reichart; C.F. Brand; A. Bernhardt; S. Schmidt; Andreas Schaefer; Stefan Blankenberg; H. Reichenspurner; Fm Wagner; T. Deuse; Markus J. Barten

Background Minimally invasive left ventricular assist device (LVAD) implantation may reduce peri‐/postoperative complications and risks associated with resternotomies. In this study, we describe our first results using a minimally invasive LVAD implantation technique (lateral thoracotomy [LT] group). These results were compared with LVAD implantations done via full median sternotomy (STX group). Methods HVAD (HeartWare, Framingham, Massachusetts, United States) implantations in 70 patients (LT group n = 22, 52 ± 15 years old; STX group n = 48, 59 ± 11 years old) were retrospectively analyzed. Minimally invasive access via left thoracotomy was feasible in 22 patients. Peri‐ and postoperative analyses of survival and adverse events were performed. Results No survival differences were observed between the LT and STX group (p = 0.43). LT patients without temporary right ventricular assist device (tRVAD) showed a significantly better survival rate compared to LT patients with concomitant tRVAD implantation (p = 0.02), which could not be demonstrated in the STX group (p = 0.11). Two LT and four STX patients were successfully bridged to heart transplantation and three STX patients were successfully weaned with subsequent LVAD explantations. LVAD‐related infections (n = 4 LT group vs n = 20 STX group, p = 0.04) were less likely in the LT group. No wound dehiscence occurred in the LT group, whereas five were observed in the STX group (p = 0.17). The amount of perioperative blood transfusions (within the first 7 postoperative days) did not differ in both study groups (p = 0.48). Conclusion The minimally invasive approach is a viable alternative with the possibility to reduce complications and should be particularly considered for bridge‐to‐transplant patients.

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T. Deuse

University of California

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