Christof Schmid

Universität Regensburg, Ratisbon, Bavaria, Germany

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Publications (467)1305.99 Total impact

  • L Rupprecht · D Lunz · A Philipp · M Lubnow · C Schmid
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    ABSTRACT: Introduction: This observational report depicts typical problems of extracorporeal membrane oxygenation cannulation from a large case series of a single center. Methods: We analysed our experience with 720 consecutive patients receiving veno-venous or veno-arterial extracorporeal membrane oxygenation focusing on the spectrum of complications occurring in a subset of 159 patients treated with percutaneous veno-arteria extracorporeal membrane oxygenation in our institution between January 2009 to December 2014. Results: The main problems were: vascular complications or ischemia of the corresponding extremity (leading to surgical revision in 16.9 % of patients); blood loss and/or relocation of cannulas. Hypoxia of the upper body (Harlequin syndrome) occurred in 8.8 % of patients. Cannulation failure and malfunction were infrequent. Careful insertion technique, close surveillance and monitoring are compelling. Conclusions: As lack of experience is the trigger of many complications, adequate training of cannulation techniques is essential to minimize adverse events.
    No preview · Article · Jan 2016

  • No preview · Article · Jan 2016 · The Thoracic and Cardiovascular Surgeon

  • No preview · Article · Jan 2016 · The Thoracic and Cardiovascular Surgeon

  • No preview · Article · Jan 2016 · The Thoracic and Cardiovascular Surgeon
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    ABSTRACT: Medical devices made of polycarbonaturethane (PCU) combine excellent mechanical properties and little biological degradation, but restricted hemocompatibility. Modifications of PCU might reduce platelet adhesion and promote stable endothelialization. PCU was modified using gas plasma treatment, binding of hydrogels, and coupling of cell-active molecules (modified heparin, anti-thrombin III (ATIII), argatroban, fibronectin, laminin-nonapeptide, peptides with integrin-binding arginine-glycine-aspartic acid (RGD) motif). Biocompatibility was verified with static and dynamic cell culture techniques. Blinded analysis focused on improvement in endothelial cell (EC) adhesion/proliferation, anti-thrombogenicity, reproducible manufacturing process, and shear stress tolerance of ECs. EC adhesion and antithrombogenicity were achieved with 9/35 modifications. Additionally, 6/9 stimulated EC proliferation and 3/6 modification processes were highly reproducible for endothelialization. The latter modifications comprised immobilization of ATIII (A), polyethyleneglycole-diamine-hydrogel (E) and polyethylenimine-hydrogel connected with modified heparin (IH). Under sheer stress, only the IH modification improved EC adhesion within the graft. However, ECs did not arrange in flow direction and cell anchorage was restricted. Despite large variation in surface modification chemistry and improved EC adhesion under static culture conditions, additional introduction of shear stress foiled promising preliminary data. Therefore, biocompatibility testing required not only static tests but also usage of physiological conditions such as shear stress in the case of vascular grafts.
    No preview · Article · Jan 2016 · Journal of Biomaterials Applications
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    ABSTRACT: Long-term survival of lung allografts is limited by chronic rejection (CR). Oxidative stress (OxS) plays a central role in the development of CR. We investigated the influence of pirfenidone (alone or in combination with everolimus) on OxS and CR. A rat model of left lung allo-transplantation (F344-to-WKY) was used to evaluate the effects of pirfenidone alone [0,85% in chow from postoperative day (POD) -3 to 20/60] and in combination with everolimus [2,5 mg/kg bw daily from POD 7 to 20/60]. Allografts of non-treated animals, everolimus treated animals and right, non-transplanted lungs were used as references. Immunohistology of myeloperoxidase (MPO), haemoxygenase-1 (HO-1), iron and platelet-derived-growth-factor-receptor-alpha (PDGFR-a) were performed. On POD 20, all groups showed severe acute rejection (ISHLT A3-4/B1R-B2R). Groups treated with pirfenidone showed a lower interstitial inflammatory infiltration and a lower participation of highly fibrotic degenerated vessels (ISHLT-D2R). In the long term follow up (POD 60), pirfenidone alone significantly reduced chronic airway rejection (ISHLT-C; p<=0.05), interstitial fibrosis (IF; p<=0.05), content of collagen (p<=0.05), expression of PDGFR-a (p<=0.05) and the deposition of iron (p<=0.05). All groups treated with pirfenidone showed a high expression of the cytoprotective enzyme HO-1 (p<=0.05). The additional application of everolimus resulted in a significant decrease of chronic airway rejection (ISHLT-C; p<=0.05), vasculopathy (ISHLT; p<=0.05) and IF (p<=0.05). In conclusion, early application of pirfenidone inhibited the progression of CR by its anti-fibrotic and anti-oxidative properties. The additional application of an m-TOR-inhibitor increased the anti-fibrotic effects of pirfenidone which resulted in a reduction of CR after experimental LTx.
    No preview · Article · Dec 2015 · Histology and histopathology
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    ABSTRACT: Objective: Extracorporeal membrane oxygenation is a rescue therapy for patients with severe lung failure. Major complications caused by extracorporeal membrane oxygenation are bleeding, thrombosis, and hemolysis. The aim of this study was to compare the impact of different extracorporeal membrane oxygenation systems on blood hemostasis in adults during veno-venous extracorporeal membrane oxygenation therapy. Methods: In a prospective randomized study of adult patients with severe acute respiratory distress syndrome requiring veno-venous extracorporeal membrane oxygenation therapy, we compared the following three different extracorporeal membrane oxygenation systems: the Cardiohelp system (Maquet Cardiopulmonary AG, Rastatt, Germany), the Dideco ECC.O5 (Sorin Group, Mirandola, MO, Italy), and the Deltastream system with Hilite 7000 LT + DP3 pumphead (Medos Medizintechnik AG, Stolberg, Germany). Hemostasis, anticoagulation, hemolysis, and inflammatory parameters were monitored. Results: Of the 54 patients included in the study, 18 patients each were randomly assigned to the three different extracorporeal membrane oxygenation systems. Exclusion criteria were acute renal failure, trauma, and surgery within 2 days. The median time on veno-venous extracorporeal membrane oxygenation support was 13.5 days (4-70 d). Median platelet count had dropped from 220.5 G/L before extracorporeal membrane oxygenation therapy to a minimum of 133 G/L by the last day of extracorporeal membrane oxygenation support. During the first 5 days of extracorporeal membrane oxygenation therapy, prothrombin fragment 1.2 (F1.2) (1.36-2.4 µM), thrombin-antithrombin complex (14.5-50 µg/L), and D-dimers (6.00-27.0 mg/L) increased, whereas fibrinogen values dropped from 5.8 to 4.1 g/L. The three different extracorporeal membrane oxygenation systems did not show any differences with regard to hemostasis, anticoagulation, hemolysis, and inflammatory parameters within the first 5 days of extracorporeal membrane oxygenation therapy. Conclusions: Over time, miniaturized veno-venous extracorporeal membrane oxygenation therapy increasingly activates coagulation. The different types of membrane oxygenators and pumps did not significantly alter hemostasis.
    No preview · Article · Dec 2015 · Critical care medicine
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    ABSTRACT: The aim of the study was to explore the prevalence and risk factors for technical-induced hemolysis in adults supported with veno-venous extracorporeal membrane oxygenation (vvECMO) and to analyze the effect of hemolytic episodes on outcome. This was a retrospective, single-center study that included 318 adult patients (Regensburg ECMO Registry, 2009-2014) with acute respiratory failure treated with different modern miniaturized ECMO systems. Free plasma hemoglobin (fHb) was used as indicator for hemolysis. Throughout a cumulative support duration of 4,142 days on ECMO only 1.7% of the fHb levels were above a critical value of 500 mg/l. A grave rise in fHb indicated pumphead thrombosis (n = 8), while acute oxygenator thrombosis (n = 15) did not affect fHb. Replacement of the pumphead normalized fHb within two days. Neither pump or cannula type nor duration on the first system was associated with hemolysis. Multiple trauma, need for kidney replacement therapy, increased daily red blood cell transfusion requirements, and high blood flow (3.0-4.5 L/min) through small-sized cannulas significantly resulted in augmented blood cell trauma. Survivors were characterized by lower peak levels of fHb [90 (60, 142) mg/l] in comparison to non-survivors [148 (91, 256) mg/l, p≤0.001]. In conclusion, marked hemolysis is not common in vvECMO with modern devices. Clinically obvious hemolysis often is caused by pumphead thrombosis. High flow velocity through small cannulas may also cause technical-induced hemolysis. In patients who developed lung failure due to trauma, fHb was elevated independantly of ECMO. In our cohort, the occurance of hemolysis was associated with increased mortality.
    Full-text · Article · Nov 2015 · PLoS ONE
  • Andreas Keyser · Harald Brodoefel · Christof Schmid

    No preview · Article · Nov 2015
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    ABSTRACT: Objective The percentage of patients undergoing cardiac surgery under some sort of psychiatric medication (PM) is not negligible. Thus, this study aimed to evaluate a possible impact of preoperative PM on the outcome after cardiac surgery. Methods A matched case-control study was conducted by including all patients who underwent myocardial revascularization and/or surgical valve operation in our institution from December 2008 till February 2011 by chart review and institutional quality assurance database (QS) analysis. Results Out of 1,949 patients included, 184 patients (9%) were identified with PM medication (group A). A control group matched for logistic EuroSCORE II, ejection fraction and age was generated (group C). Patients with PM were in mean significantly longer on the intensive care unit (A: 4.94 days; 95% confidence interval (CI), 3.9-5.9 days vs. C: 3.24 days; CI, 2.84-3.64 days; p = 0.003), had longer mechanical ventilation times (A: 36.70 hours; CI, 19.81-53.59 hours vs. C: 20.14 hours; CI, 14.61-25.68 hours; p = 0.258), and significantly more episodes of respiratory insufficiencies (A: 31 episodes [17%] vs. C: 17 episodes [9%]; p = 0.002). Regression analysis revealed preoperative PM as a significant risk factor for respiratory insufficiency (odds ratio: 1.99, CI: 1.0-3.74; p = 0.04). Chest tube drainage (A: 690 mL, CI: 571-808 mL vs. C: 690 mL; CI: 496-884 mL, p = 0.53) and the total amount of red blood cell transfusion units were similar (A: 1.69 units; CI: 1.21-2.18 units vs. C: 1.50 units; CI: 1.04-1.96 units; p = 0.37). Sternal dehiscence requiring sternal refixation was significantly more frequent in A (12 patients [7%] vs. C: 2 patients [1%]; odds ratio: 6.3, CI: 1.4-28.7; p = 0.01). The 30-day mortality was similar in both groups (A: 6 patients [3%] vs. C: 4 patients [2%]; odds ratio: 1.5; CI: 0.4-5.4; p = 0.5); however, the 100-day mortality was near significantly higher in group A (A: 14 patients (8%) vs. C: 6 patients (3%); odds ratio: 2.4, CI: 0.9-6.5, p = 0.057). Conclusion Patients with preoperative PM developed complications more frequently compared with a matched control group. The underlying multifactorial mechanisms remain unclear. Patients under PM need to be identified and particular care including optimal pre- and postoperative psychiatric assistance is recommended.
    No preview · Article · Oct 2015 · The Thoracic and Cardiovascular Surgeon
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    ABSTRACT: Multipotent progenitor cells were mobilized during pediatric extracorporeal membrane oxygenation (ECMO). We hypothesize that these cells also adhered onto polymethylpentene (PMP) fibers within the membrane oxygenator (MO) during adult ECMO support. Mononuclear cells were removed from the surface of explanted PMP-MOs (n = 16). Endothelial-like outgrowth and mesenchymal-like cells were characterized by flow cytometric analysis using different surface markers. Spindle-shaped attaching cells were identified early, but without proliferative activity. After long-term cultivation palisading type or cobblestone-type outgrowth cells with high proliferative activity appeared and were characterized as (i) leukocytoid CD45+/CD31+ (CD133+/VEGFR-II+/CD90+/CD14+/CD146dim/CD105dim); (ii) endothelial-like CD45-/CD31+ (VEGF-RII+/CD146+/CD105+/CD133-/CD14-/CD90-); and (iii) mesenchymal-like cells CD45-/CD31- (CD105+/CD90+/CD133dim/VEGFR-II-/CD146-/CD14-). The distribution of the cell populations depended on the MO and cultivation time. Endothelial-like cells formed capillary-like structures and did uptake Dil-acetylated low-density lipoprotein. Endothelial- and mesenchymal-like cells adhered on the surface of PMP-MOs. Further research is needed to identify the clinical relevance of these cells.
    No preview · Article · Oct 2015 · Artificial Organs
  • K. Lucas · A. Gessner · D. Wehner · T. Schmid · C. Schmid · K. Lehle

    No preview · Article · Oct 2015 · Transplant International

  • No preview · Article · Oct 2015 · Transplant International
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    ABSTRACT: Interhospital transfer of patients experiencing circulatory failure and shock has a significant risk of cardiovascular deterioration and death. Extracorporeal life support (ECLS) is a rescue tool for hemodynamic stabilization that makes patient transportation much safer. Demographic data, clinical course, and outcome data were reviewed for patients who underwent placement of a venoarterial ECLS in a remote hospital and were transported to our tertiary care facility. 68 patients were transported to our center with ECLS. The majority of these patients (79%) underwent cardiopulmonary resuscitation during or immediately prior to ECLS initiation.The mean patient age was 52 years, and 53 patients were male. The most common underlying diagnosis was acute coronary syndrome (60%). Overall, 23 patients underwent consecutive cardiosurgical procedures, including coronary artery bypass grafting in 12, and left ventricular assist device and biventricular assist device implantation in 11. The median duration of ECLS was 5 days. None of the patients died during transportation. Twelve of the surgically treated patients survived, as well as 21 patients with non-surgical treatment, which resulted in an overall survival of 33 patients (48.5%). ECLS-facilitated patient transfer enables safe interhospital transfer of critically ill patients. In this study, a relevant percentage of patients were in need of a cardiosurgical intervention. The long-term survival rate of these patients supports the further use of this time-, cost- and personnel-demanding strategy. Copyright © 2015. Published by Elsevier Ireland Ltd.
    Full-text · Article · Jun 2015 · Resuscitation
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    ABSTRACT: Advanced age is a known risk factor for morbidity and mortality after coronary artery bypass grafting (CABG). Minimized extracorporeal circulation (MECC) has been shown to reduce the negative effects associated with conventional extracorporeal circulation (CECC). This trial assesses the impact of MECC on the outcome of elderly patients undergoing CABG. Eight hundred and seventy-five patients (mean age 78.35 years) underwent isolated CABG using CECC (n=345) or MECC (n=530). The MECC group had a significantly shorter extracorporeal circulation time (ECCT), cross-clamp time and reperfusion time and lower transfusion needs. Postoperatively, these patients required significantly less inotropic support, fewer blood transfusions, less postoperative hemodialysis and developed less delirium compared to CECC patients. In the MECC group, intensive care unit (ICU) stay was significantly shorter and 30-day mortality was significantly reduced [2.6% versus 7.8%; p<0.001]. In conclusion, MECC improves outcome in elderly patients undergoing CABG surgery. © The Author(s) 2015.
    No preview · Article · Jun 2015 · Perfusion
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    ABSTRACT: Cerebral thromboembolism builds the Achilles heel for patients on left ventricular support (LVAD). Thrombolytic therapy is usually contraindicated considering the increased risk of intracranial hemorrhage in LVAD patients under therapeutic oral anticoagulation with concomitant platelet inhibition. We report on an alternative approach to this dilemma. On day 1091 of LVAD support (INCOR(R) Berlin Heart) a 69-year-old male patient was admitted to a rural hospital unconscious with a left sided hemiplegia. Cerebral computed tomography (cCT) with CT-angiography revealed a thrombembolic distal basilar artery occlusion. The patient was immediately transported to our medical center, where an interventional thrombectomy restored full patency of the vessel. The patient recovered without neurological sequelae within days. This case highlights the fact that patients on LVAD support with a neurological event should be immediately transferred to a neurovascular center for appropriate treatment including a neurointervention.
    No preview · Article · Apr 2015 · ASAIO Journal
  • M. von Suesskind · L. Keil · C. Schmid · S.W. Hirt · K. Lehle

    No preview · Article · Apr 2015 · The Journal of Heart and Lung Transplantation
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    ABSTRACT: Objectives: We demonstrate a multislice computed tomography (MSCT)-based method to calculate the prediction of the so-called 'line of perpendicularity' (LOP) and the 'implanter's views' (IVs) for transcatheter aortic valve implantation (TAVI) procedures. The LOP represents all possible angiographic angulations that result in an orthogonal view to the aortic annulus plane. The IVs allow visual confirmation of correct implantation planes, and are crucial for the commissural aligned implantation of second-generation TAVI prostheses. Methods: The LOP and IVs of 335 concomitant patients were prospectively analysed using multiple plane reconstruction (MPR) of the patient's MSCT scans. Exclusion criteria were bicuspid valves (n = 18) and valve-in-valve TAVI (n = 15). In the MPRs, the aortic cusps' lowest points were marked. With the marker's three-dimensional coordinates, the graph of the LOP with the IVs was calculated and plotted using vector mathematics. In the last 244 cases, the IV with the right coronary cusp in front was chosen for the first aortic root angiogram of the TAVI procedure. The finally used angulation was confirmed by aortic angiogram prior to the valve implantation. Solid angle differences that show the combined left anterior oblique/right anterior oblique and cranio/caudal movement of the C-arm allow quantification of corrections as well as demonstrate interindividual variations. Results: There is a broad interindividual variation of the aortic valve's topology with solid angle variations of up to 74°. The shape of the LOPs is extremely varying, especially regarding the slope of the curve that indicates differences in valve orientations. Among the 244 patients for whom we used the prediction for the procedure, the first angiogram was considered perfect for implantation without further corrections in 97% (n = 237) of them. In case of the 7 patients with subsequent corrections, the mean solid angle between the prediction and the final angiogram prior to implantation was 6.2° (±5°); the largest correction was 14°. Conclusions: Prediction of the implantation plane by analysing the patient's MSCT is highly reliable in achieving an adequate view of the aortic annulus in TAVI. The analysis of LOPs showed the large interindividual differences that permit using a standard implantation plane. Therefore, we strongly recommend determining the LOP and IVs during the patient's screening process in each single TAVI case.
    No preview · Article · Mar 2015 · European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery
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    ABSTRACT: Anti-endothelial cell antibodies (AECA) may be involved in the development of heart allograft rejection. Its detection might be a cheap and noninvasive method to identify high-risk patients. An indirect immunofluorescence method on human umbilical vein endothelial cells was used to investigate the presence of AECAs in 260 pre- and post-transplant serum samples sequentially collected from 34 patients within the first year after heart transplantation (HTX). The presence of AECAs before (23.5 %) and early after HTX (14.7 %) was associated with a significantly increased risk of early acute rejection (75 and 60 %, respectively) compared to 33 % in AECA-negative patients (p = 0.049). Moreover, rejections from AECA-positive patients were more severe (p = 0.057) with a significantly increased incidence of multiple (p = 0.025). The mean number of the sum of rejection episodes was significantly higher in AECA-positive patients (p ≤ 0.05). Patients free of AECAs mainly received mycophenolate mofetil as primary immunosuppression (p = 0.067). Nevertheless, the presence of AECAs did not affect long-term outcome and mortality of HTX patients. Despite a low number of patient samples, the detection of AECAs before and early after HTX could be used as a biomarker for an increased risk of early acute rejection in high-risk patients. This easy method might be a valuable tool to support screening procedures to improve individualized immunosuppressive therapy.
    No preview · Article · Mar 2015 · Heart and Vessels

  • No preview · Article · Mar 2015 · Journal of the American College of Cardiology

Publication Stats

4k Citations
1,305.99 Total Impact Points


  • 2008-2015
    • Universität Regensburg
      • Department of Cardiac, Thoracic and Vascular Surgery near the Heart
      Ratisbon, Bavaria, Germany
  • 2011-2014
    • Universitätsklinikum Freiburg
      • Department of Cardiothoracic and Vascular Surgery
      Freiburg an der Elbe, Lower Saxony, Germany
  • 2007-2014
    • University Hospital Regensburg
      • Klinik und Poliklinik für Herz-, Thorax- und herznahe Gefäßchirurgie
      Ratisbon, Bavaria, Germany
  • 2004-2012
    • University of Duisburg-Essen
      • Institut für Psychologie
      Essen, North Rhine-Westphalia, Germany
  • 2001-2012
    • Universitätsklinikum Münster
      • Department für Kardiologie und Angiologie
      Muenster, North Rhine-Westphalia, Germany
  • 2009
    • Martin Luther University of Halle-Wittenberg
      • Clinic for Internal Medicine III
      Halle-on-the-Saale, Saxony-Anhalt, Germany
  • 1995-2008
    • University of Münster
      • Department of Neurology
      Muenster, North Rhine-Westphalia, Germany
  • 2006
    • University of Zurich
      Zürich, Zurich, Switzerland
  • 1997-2003
    • EUREGIO-KLINIK Albert-Schweitzer-Straße GmbH
      Nordhorn, Lower Saxony, Germany
  • 2001-2002
    • Columbia University
      New York City, New York, United States
  • 1996
    • Justus-Liebig-Universität Gießen
      • Department of Internal Medicine
      Gieben, Hesse, Germany