Thomas Walther

Kerckhoff Klinik, Stadt Bad Nauheim, Hesse, Germany

Are you Thomas Walther?

Claim your profile

Publications (509)1433.03 Total impact

  • 6th Joint Conference in Cardiothoracic Surgery & The Swedish Thoracic Meeting, Gothenburg, Sweden; 09/2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: Superior aortic valve hemodynamic performance can accelerate left ventricular mass regression and enhance survival and functional status after surgical aortic valve replacement. This can be achieved by rapid deployment aortic valve replacement using a subannular balloon-expandable stent frame, which functionally widens and reshapes the left ventricular outflow tract, to ensure a larger effective orifice area compared with conventional surgical valves. We report the intermediate-term follow-up data from a large series of patients enrolled in the Surgical Treatment of Aortic Stenosis With a Next Generation Surgical Aortic Valve (TRITON) trial.
    Journal of Thoracic and Cardiovascular Surgery 08/2014; · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The German Aortic Valve Registry (GARY) seeks to provide information on a real-world, all-comers basis for patients undergoing aortic valve interventions. This registry comprises patients undergoing the complete spectrum of transcutaneous and conventional surgical aortic valve interventions. The aim of this study was to use the GARY registry to evaluate conventional and catheter-based aortic valve interventions in several risk groups.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 07/2014; · 2.40 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Myocardial injury after transcatheter aortic valve replacement (TAVR) is common, but its cause and relationship to the extent of myocardial tissue loss remain unclear.
    Journal of the American College of Cardiology 07/2014; 64(4):349-57. · 14.09 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Owing to a considerable shift toward bioprosthesis implantation rather than mechanical valves, it is expected that patients will increasingly present with degenerated bioprostheses in the next few years. Transcatheter aortic valve-in-valve implantation is a less invasive approach for patients with structural valve deterioration; however, a comprehensive evaluation of survival after the procedure has not yet been performed.
    JAMA The Journal of the American Medical Association 07/2014; 312(2):162-70. · 29.98 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Transcatheter aortic valve implantation (TAVI) without predilatation has fewer procedural steps and thereby potentially fewer complications. This has been demonstrated for the antegrade transapical access; however, whether TAVI can be safely performed without predilatation using the retrograde transfemoral route is unknown.HypothesisWe postulated that TAVI is feasible with a balloon-expandable device without predilatation using the retrograde transfemoral route.Methods Twenty-six consecutive patients with stenosis of the native aortic valve (AV) undergoing transfemoral TAVI with the Edwards SAPIEN XT prosthesis without predilatation were enrolled in this retrospective study and compared with 30 patients treated previously with predilatation.ResultsThe procedure was successfully performed in all 26 patients, irrespective of the AV area and the extent of AV calcification. At baseline mean AV area, mean AV gradient, and median left ventricular ejection fraction were 0.7 ± 0.2 cm2, 36.0 ± 17.3 mm Hg, and 55.0% (interquartile range [IQR], 35.0–60.0], respectively; prior to discharge these values were 1.7 ± 0.3 (P < 0.001), 9.8 ± 6.1 mm Hg (P < 0.001), and 57.5% (IQR, 38.7–60.0) (P = not significant). Postdilatation was required in 3 patients due to aortic regurgitation >2°; this was reduced by the procedure to <2° in all cases. Radiation dose and amount of contrast dye were significantly reduced in comparison with the predilatation group. No periprocedural neurological adverse events occurred. Mortality at 30 days was 0%.ConclusionsTAVI without predilatation using the transfemoral Edwards SAPIEN XT valve is feasible and safe. Larger studies are required to further evaluate this approach.
    Clinical Cardiology 07/2014; · 1.83 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Transapical aortic valve implantation (TA-AVI) using the Edwards SAPIEN™ prosthesis has evolved into a routine procedure for selected high-risk elderly patients. The recently introduced SAPIEN™ delivery system (Ascendra II+™) with an added nose cone seems to facilitate direct valve implantation without prior balloon valvuloplasty (BAV). Here, we report our initial experience with this device. A total of 128 patients were enrolled in the study in 2012 and 2013 and were designated Cohort I. For a subset of 79 patients, exact cardio- computed tomography-based measurements were available; these patients were assigned to Cohort II. All patients received SAPIEN XT™ valves using the TA approach. TA-AVI without pre-ballooning was performed in 31.2% (Cohort I) and 31.6% (Cohort II) of patients. To adjust for baseline variables, propensity score (PS)-based pair matching was used. All valves were implanted successfully. The use of PS matching resulted in bias reduction for both cohorts. For Cohort I, there were no significant differences in the primary end points, which were aortic valve incompetence ≥2+, Pmean postimplantation, major stroke, transient ischaemic attack (TIA), requirement for post-dilatation and necessity for new pacemaker implantation. As expected, fluoroscopy time was significantly lower in no-BAV patients. In Cohort II, the 30-day TIA rate was lower in the no-BAV group. Direct TA implantation of the SAPIEN valve without pre-ballooning is feasible, safe, does not seem to compromise functional outcomes and may be associated with fewer neurological events.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 03/2014; · 2.40 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Transcatheter aortic valve implantation (TAVI) is an increasingly common procedure in elderly and multimorbid patients with aortic stenosis. We aimed at developing a pre-procedural risk evaluation scheme beyond current surgical risk scores. We developed a risk algorithm for 1-year mortality in two cohorts consisting of 845 patients undergoing routine TAVI procedures by commercially available devices, mean age 80.9 ± 6.5, 51 % women. Clinical variables were determined at baseline. Multivariable Cox regression related clinical data to mortality (n = 207 deaths). To account for variability related to age and sex and by enrolment site we forced age, sex, and cohort into the score model. Body mass index, estimated glomerular filtration rate, hemoglobin, pulmonary hypertension, mean transvalvular gradient and left ventricular ejection fraction at baseline were most strongly associated with mortality and entered the risk prediction algorithm [C-statistic 0.66, 95 % confidence interval (CI) 0.61-0.70, calibration χ (2)-statistic = 6.51; P = 0.69]. Net reclassification improvement compared to existing surgical risk predication schemes was positive. The score showed reasonable model fit and calibration in external validation in 333 patients, N = 55 deaths (C-statistic 0.60, 95 % CI 0.52-0.68; calibration χ (2)-statistic = 16.2; P = 0.06). Additional measurement of B-type natriuretic peptide and troponin I did not improve the C-statistic. Frailty increased the C-statistic to 0.71, 95 % CI 0.65-0.76. We present a new risk evaluation tool derived and validated in routine TAVI cohorts that predicts 1-year mortality. Biomarkers only marginally improved risk prediction. Frailty increased the discriminatory ability of the score and needs to be considered. Risk algorithms specific for TAVI may help to guide decision-making when patients are evaluated for TAVI.
    Clinical Research in Cardiology 03/2014; · 3.67 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Assessment of perioperative risk of elderly patients in cardiac surgery is difficult, and most of the common risk scores show over- or underestimation. Two frailty scores, the comprehensive assessment of frailty (CAF) score and the Frailty predicts death One yeaR after CArdiac Surgery Test (FORECAST), were developed as additional tools to estimate the preoperative mortality risk, taking into consideration the frailty status of elderly patients. Four hundred and fifty patients who were referred for elective cardiac surgery were included. All the patients were assessed with the CAF test and the FORECAST. Thirty-day and 1-year mortality were evaluated by telephone interview. Univariate and bivariate logistic regression were performed to test the predictive power of the tests on mortality. Correlation of the scores with age was calculated with Spearman ranks. Three commensurate groups were built for each of the frailty scores and the outcome was compared between the groups. All analyses were performed for Society of Thoracic Surgeons (STS) and European System for Cardiac Operative Risk Evaluation (EuroSCORE) accordingly. A total of 227 male and 223 female patients were included. Thirty-day mortality was 6.1%, and 1-year mortality was 13.3%. Logistic regression showed that both scores are able to predict 30-day as well as 1-year mortality. Bivariate logistic regression showed that both frailty scores give relevant additional information to the STS and EuroSCORE for the prediction of 1-year mortality. The frailty scores were only weakly correlated with age in contrast to STS and EuroSCORE and therefore can be used as indicator of the biological age of patients besides the numerical age. Survival up to 1 year was relevantly reduced in the group of patients with the higher frailty scores. CAF and FORECAST are additional tools to evaluate elderly patients adequately before elective cardiac surgery, and showed an association with short- and mid-term mortality independently of age.
    Interactive Cardiovascular and Thoracic Surgery 02/2014; · 1.11 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Precise measurements of aortic annulus dimensions are crucial for prosthesis size selection in patients undergoing transcatheter aortic valve implantation (TAVI). The so-called effective diameter (derived from area) measured in multislice computed tomography (MSCT) images has evolved to be the most precise measurement tool. Usually, the operator must manually adjust the aortic annular plane. Syngo Aortic ValveGuide (Siemens Healthcare) is a new software tool that allows for automatic aortic root reconstruction and annular plane detection. The aim of this study was to compare the effective diameter measured in automatically detected and manually adjusted annular plane. Seventy-three raw image datasets of preoperative TAVI MSCT scans were analysed using our institutional gold standard (3Mensio Valves™) with manual annular plane adjustment and using Aortic ValveGuide with automatic annular plane detection. The aortic annular circumference was manually marked for both software tools, and the effective diameter was calculated using the formula: effective diameter = 2 × √(circumferential area/π). Automatic annulus plane detection using Syngo Aortic ValveGuide worked well in all MSCT scans. Minor manual adjustment of the detected plane was necessary in only 3 patients. The mean effective aortic annulus diameter was 23.1 ± 2.4 mm for 3Mensio and 23.3 ± 2.4 mm for Syngo Aortic ValveGuide. Bland-Altman analysis of both imaging software tools showed good agreement (mean difference of 0.16 mm and limits of agreement of -0.48 to 0.80 mm). Effective aortic annulus diameter measured with Syngo Aortic ValveGuide, as a new imaging software that allows for automatic aortic annular plane detection, shows good agreement to gold standard measurements. Automatic annulus plane detection might reduce the effort for MSCT analysis and may lead to more reproducible aortic annulus measurements. Aortic ValveGuide is part of the DynaCT and in future aortic annulus dimension measurements may be feasible during intraoperatively acquired DynaCT.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 01/2014; · 2.40 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: During the past years TAVI has evolved to a standard technique for the treatment of high risk patients suffering from severe aortic stenosis. Worldwide the number of TAVI procedures is increasing exponentially. In this context both the transapical antegrade (TA) and the transfemoral retrograde (TF) approach are predominantly used and can be considered as safe and reproducible access sites for TAVI interventions. As a new technology TAVI is in a constant progress regarding the development of new devices. While in the first years only the Edwards SAPIEN™ and the Medtronic CoreValve™ prostheses were commercial available, recently additional devices obtained CE-mark approval and others have entered initial clinical trials. In addition to enhance the treatment options in general, the main driving factor to further develop new device iterations is to solve the drawbacks of the current TAVI systems: paravalvular leaks, occurrence of AV-blocks and the lack of full repositionability.
    Current Cardiology Reviews 12/2013;
  • [Show abstract] [Hide abstract]
    ABSTRACT: During the past years transcatheter aortic valve implantation (TAVI)has evolved to a standard technique for the treatment of high risk patients suffering from severe aortic stenosis. Worldwide the number of TAVI procedures is increasing exponentially. In this context both the transapicalantegrade(TA) and the transfemoralretrograde (TF) approach are predominantly used and can be considered as safe and reproducible access sites for TAVI interventions. As a new technology TAVI is in a constant progress regarding the development of new devices. While in the first years only the Edwards SAPIEN™ and the Medtronic CoreValve™ prostheses were commercial available, recently additional devices obtained CE-mark approvaland othershave entered initial clinical trials. In addition to enhance the treatment options in general, the main driving factor to further develop new device iterations is to solve the drawbacks of the current TAVI systems: paravalvular leaks, occurrence of AV-blocks and the lack of full repositionability.
    Current Cardiology Reviews 12/2013;
  • [Show abstract] [Hide abstract]
    ABSTRACT: In the past years transcatheter aortic valve implantation became a highly standardized option for the treatment of high-risk patients suffering from severe aortic stenosis. The number of transcatheter aortic valve implantation procedures is increasing exponentially worldwide. In this context the transapical approach should be considered as a safe and reproducible alternative access to the left ventricle with some specific advantages compared with transfemoral, transaortic and transsubclavian approach due to its antegrade nature. To further ease the transapical access first apical closure devices have been developed and entered first clinical trials.
    Expert Review of Cardiovascular Therapy 12/2013; 11(12):1613-7.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The transplantation of mesenchymal stem cells (MSCs) represents a promising approach for treating the ischemic and the nonischemic diseased heart. The positive effects of transplanting these cells could be shown, but the exact mechanisms remain unknown. We evaluated whether the injection site affects the improvement in left ventricular (LV) ejection fraction (EF) and angiogenesis in doxorubicin (Dox)-induced failing hearts. Heart failure was induced in New Zealand white rabbits by Dox treatment, followed by right ventricular MSC transplantation (RV-MSC, n = 6), LV MSC transplantation (LV-MSC, n = 6), sham treatment (sham group, n = 6), or no therapy (Dox group, n = 5). Healthy rabbits were used as control group (n = 8). Cells were isolated after bone marrow aspiration and transplanted locally into the ventricular myocardium. After 4 weeks, cardiac function and capillary density (CD31 staining) were measured. The transplantation of MSCs increased the EF significantly (LV-MSC, 39.0% ± 1.4%, and RV-MSC, 39.2% ± 2.6%, vs sham group, 29.8% ± 3.7%; P < 0.001), without significance between the MSC groups (P = 0.858). Neither the evidence of a transdifferentiation nor any signs of cell engraftment of transplanted cells could be found. The capillary density (capillaries/high-power field) increased in both MSC groups compared with the sham group (LV-MSC by 8.3% ± 3.4%; and RV-MSC, 8.1% ± 2.2%; P < 0.05), without significance between the two MSC groups (P = 0.927). Injection of autologous MSCs in Dox-induced cardiomyopathic rabbit hearts improves EF and enhances angiogenesis. Despite local application, we observed global effects on heart function and capillary density without significant difference between right and LV injection. The paracrine mechanism might be one possible explanation for these findings.
    Innovations Technology and Techniques in Cardiothoracic and Vascular Surgery 11/2013;
  • Thomas Walther, Mani Arsalan, Won Kim, Jörg Kempfert
    [Show abstract] [Hide abstract]
    ABSTRACT: Transcatheter aortic valve implantation is a relatively new technique to treat elderly and high-risk patients with aortic stenosis using a retrograde transfemoral, transsubclavian, transaortic or an antegrade transapical approach. TAVI procedures can be divided into two parts: the access to the cardiovascular system, and valve positioning and implantation. Regarding access, an antegrade transapical approach is intuitively easy to perform and thus the logical approach. At present a lateral mini-thoracotomy is required, but for the future percutaneous access and closure systems will be available. The transapical approach per se offers plenty of advantages as it is easy to perform, is very close to the target, antegrade, allows for easy guidewire insertion together with simple antegrade valve placement and a very controlled implantation. Despite this, in clinical reality many sites use a "transfemoral first" approach to TAVI, which is based merely on the belief that this is supposed to be less invasive; however, this belief is not substantiated by evidence-based data. In effect, the transapical approach offers the lowest access-related complication rates, and should therefore be the access of choice for many patients.
    EuroIntervention: journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology 09/2013; 9 Suppl:S19-24. · 3.17 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Aortic stenosis is a frequent valvular disease especially in elderly patients. Catheter-based valve implantation has emerged as a valuable treatment approach for these patients being either at very high risk for conventional surgery or even deemed inoperable. The German Aortic Valve Registry (GARY) provides data on conventional and catheter-based aortic procedures on an all-comers basis. A total of 13 860 consecutive patients undergoing repair for aortic valve disease [conventional surgery and transvascular (TV) or transapical (TA) catheter-based techniques] have been enrolled in this registry during 2011 and baseline, procedural, and outcome data have been acquired. The registry summarizes the results of 6523 conventional aortic valve replacements without (AVR) and 3464 with concomitant coronary bypass surgery (AVR + CABG) as well as 2695 TV AVI and 1181 TA interventions (TA AVI). Patients undergoing catheter-based techniques were significantly older and had higher risk profiles. The stroke rate was low in all groups with 1.3% (AVR), 1.9% (AVR + CABG), 1.7% (TV AVI), and 2.3% (TA AVI). The in-hospital mortality was 2.1% (AVR) and 4.5% (AVR + CABG) for patients undergoing conventional surgery, and 5.1% (TV AVI) and AVI 7.7% (TA AVI). The in-hospital outcome results of this registry show that conventional surgery yields excellent results in all risk groups and that catheter-based aortic valve replacements is an alternative to conventional surgery in high risk and elderly patients.
    European Heart Journal 09/2013; · 14.72 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Coronary artery disease (CAD) is a leading cause of morbidity and mortality in western countries and is of significant socio-economic importance due to its increasing prevalence. Until percutaneous coronary interventions (PCI) were established, CAD could only be treated by surgical revascularization or pharmacological therapy. In-stent restenosis remains a major problem after stent implantation. However, the use of new materials and stent coatings have led to a significant reduction in in-stent restenosis. Thus, surgical revascularization and PCI are currently of equal value for the treatment of CAD. The decision-making for PCI or surgical revascularization depends on various factors such as number of diseased vessels, complexity of the coronary stenoses, concomitant diseases, and the patient's general condition. The therapeutic regime of every patient should be adjusted to the recommendations of the European and German Society for Cardiology, while controversial and complex cases should be discussed in an interdisciplinary case conference ("heart team").
    Herz 07/2013; · 0.78 Impact Factor
  • Source
    Journal of the American College of Cardiology 06/2013; · 14.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background. Acute kidney injury (AKI) is a common complication after cardiac surgery. Neutrophil gelatinase-associated lipocalin (NGAL) may be an early biomarker for cardiac surgery-associated (CSA) AKI. We investigated whether increased urinary NGAL concentrations were predictive of AKI within 4 days after surgery and of mortality within 9 months. Methods. Consecutive patients (n = 141) undergoing major cardiac surgery were included. Creatinine, blood urea nitrogen, cystatin C and urinary NGAL were measured before, 4 hours and 4 days after extracorporeal circulation. Results. AKI was observed in 47 (33.3%) patients. The 4-hour urinary NGAL measurement was an independent predictor of stage 2 and 3 AKI (AUC 0.901; 95% CI 0.81-0.99). Patients with AKI had a higher 9-month mortality rate (19.1% vs. 3.2%; logrank 10.9; P = 0.001; HR 19.8; 95% CI 3.7-107.1). Urinary NGAL was not predictive of mortality within 9 months after surgery. Conclusion. Urinary NGAL is a biomarker for very early risk stratification of AKI after cardiac surgery and may be useful as a basis for early interventional strategies to prevent CSA-AKI.
    Scandinavian journal of clinical and laboratory investigation 05/2013; · 1.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE: This study aimed to identify predictors of mortality in patients with out-of-hospital cardiac arrest (OHCA) undergoing in-hospital extracorporeal life support system (ECLS) treatment. METHODS: We retrospectively studied the characteristics and clinical outcomes of 28 patients (January 2010 and December 2011) with OHCA and veno-arterial ECLS implemented during ongoing cardiopulmonary resuscitation (CPR) upon admission to the cath lab. Baseline left ventricular ejection fraction (LVEF) was determined after ECLS implantation and then every 24 h during and after successful weaning from ECLS. RESULTS: Overall 30-day survival rate was 39.3 % (11 of 28 patients). Baseline characteristics, initial laboratory measurements, and LVEF on admission were not significantly different between survivors and non-survivors. There was no difference regarding median CPR duration [survivors 44.0 min (IQR 31.0-45.0) vs. non-survivors 53.0 min (IQR 40.0-61.3); P = 0.23]. Door-to-ECLS implantation time was significantly longer in non-survivors [42.5 min (IQR 28.0-56.5) vs. 25.0 min (IQR 21.0-30.0); P < 0.01]. ECLS treatment duration was not significantly different between the two groups [survivors: 4.0 days (IQR 1.5-7.5) vs. non-survivors 6.5 days (IQR 1.0-8.0); P = 0.69]. LVEF significantly improved in survivors during ECLS treatment (mean ± SD survivor 47.5 ± 14.7 % vs. non-survivor 23.3 ± 14.9 %; P < 0.01). The door-to-ECLS implantation time was the only significant and independent predictor of 30-day mortality in multivariate Cox regression analysis (P = 0.04). Kaplan-Meier survival analysis showed a benefit favouring patients with a door-to-ECLS implantation time <30 min (log rank 6.29; P = 0.01). CONCLUSION: A door-to-ECLS implantation time <30 min significantly improves 30-day outcomes in patients with OHCA.
    Clinical Research in Cardiology 05/2013; · 3.67 Impact Factor

Publication Stats

8k Citations
1,433.03 Total Impact Points

Institutions

  • 2010–2014
    • Kerckhoff Klinik
      • • Department of Cardiology
      • • Department of Heart Surgery
      Stadt Bad Nauheim, Hesse, Germany
    • Siemens
      München, Bavaria, Germany
    • National Health Service
      • Department of Cardiothoracic Surgery
      Radditch, England, United Kingdom
    • Laboklin GmbH
      Bad Kissingen, Bavaria, Germany
  • 2013
    • Isar Heart Center
      Münchenbernsdorf, Thuringia, Germany
    • Justus-Liebig-Universität Gießen
      Gieben, Hesse, Germany
  • 2012
    • Deutsche Gesellschaft für Thorax-, Herz- und Gefäßchirurgie e.V. 
      Berlín, Berlin, Germany
    • Medical University of Vienna
      Wien, Vienna, Austria
    • King’s Health Partners
      Londinium, England, United Kingdom
  • 2007–2012
    • Kunststoff-Zentrum in Leipzig
      Leipzig, Saxony, Germany
    • Universität Potsdam
      Potsdam, Brandenburg, Germany
  • 1995–2012
    • University of Leipzig
      • • Lehrstuhles für Herzchirurgie
      • • Klinik und Poliklinik für Kinderchirurgie
      Leipzig, Saxony, Germany
    • Georg-August-Universität Göttingen
      Göttingen, Lower Saxony, Germany
  • 2011
    • University of Duisburg-Essen
      Essen, North Rhine-Westphalia, Germany
    • Erasmus Universiteit Rotterdam
      • Department of Cardio-Thoracic Surgery
      Rotterdam, South Holland, Netherlands
    • Hospital Universitari Germans Trias i Pujol
      • Department of Cardiac Surgery
      Badalona, Catalonia, Spain
  • 2010–2011
    • University of Zurich
      • Department of Cardiovascular Surgery
      Zürich, Zurich, Switzerland
    • The University of Western Ontario
      • • Division of Cardiac Surgery
      • • Department of Surgery
      London, Ontario, Canada
  • 2008
    • Hôpital Bichat - Claude-Bernard (Hôpitaux Universitaires Paris Nord Val de Seine)
      Lutetia Parisorum, Île-de-France, France
    • Hull York Medical School
      York, England, United Kingdom
  • 2006–2008
    • Charité Universitätsmedizin Berlin
      • Department of Cardiology and Pulmonology
      Berlin, Land Berlin, Germany
  • 2004–2005
    • Erasmus MC
      • Department of Farmacology and Vascular Medicine
      Rotterdam, South Holland, Netherlands
  • 2000–2005
    • Humboldt-Universität zu Berlin
      • Department of Biology
      Berlín, Berlin, Germany
    • Stanford University
      • Department of Cardiothoracic Surgery
      Stanford, CA, United States
  • 1999–2004
    • Freie Universität Berlin
      Berlín, Berlin, Germany
  • 2000–2002
    • Fachhochschule der Wirtschaft
      Paderborn, North Rhine-Westphalia, Germany
  • 1998–2001
    • Max-Delbrück-Centrum für Molekulare Medizin
      • Experimental and Clinical Research Center (ECRC)
      Berlín, Berlin, Germany
  • 1994–1997
    • Universitätsmedizin Göttingen
      • Department of Thoracic and Cardiovascular Surgery
      Göttingen, Lower Saxony, Germany