Sebastian Michel

First experience with heterotopic thoracic pig-to-baboon cardiac xenotransplantation

Bauer A, Postrach J, Thormann M, Blanck S, Faber C, Wintersperger B, Michel S, Abicht J‐M, Christ F, Schmitz C, Schmoeckel M, Reichart B, Brenner P. First experience with heterotopic thoracic pig‐to‐baboon cardiac xenotransplantation.u2028Xenotransplantation 2010; 17: 243–249.

Administration of GAS914 in an orthotopic pig‐to‐baboon heart transplantation model

Abstract:u2002 Background:u2002 Long‐term survival of transgenic cardiac xenografts is currently limited by a form of humoral rejection named acute vascular rejection. Preformed and elicited cytotoxic antibodies against Galα(1,3)Gal terminating carbohydrate chains, known as the primary cause of hyperacute rejection, are crucial for this process. We investigated whether GAS914, a soluble, polymeric form of a Galα(1,3)Gal trisaccharide would sufficiently minimize xenograft rejection of hDAF‐transgenic pig hearts orthotopically transplanted into baboons.

Use of Methylene Blue in the Treatment of Refractory Vasodilatory Shock After Cardiac Assist Device Implantation: Report of Four Consecutive Cases

Vasodilatory shock frequently occurs after cardiac surgery, particularly after cardiac assist device implantation. This complication is often associated with high mortality, especially if refractory to conventional vasoconstrictor treatment. Methylene blue, a guanylate cyclase inhibitor, has been successfully used in the management of vasodilatory shock associated with cardiopulmonary bypass. We present four successive cases after implantation of cardiac assist devices suffering from norepinephrine and vasopressin refractory severe vasodilatory shock. In all patients, administration of a single dose of methylene blue (2 mg/kg body weight) resulted in an immediate and persistent decrease in vasoconstrictor dosages and serum lactate concentrations. Despite of this benefit, all patients deceased during hospital stay, however, this was not related to the methylene blue treatment. Methylene blue seems to be a promising therapeutical option in patients with otherwise resistant vasodilatory shock after cardiac assist device implantation. However, controlled clinical trials are necessary to substantiate safety and efficacy.

Platelet factor 4-positive thrombi adhering to the ventricles of a ventricular assist device in patients with heparin-induced thrombocytopenia type II.

BACKGROUNDnThromboembolism is a major complication in patients with ventricular assist devices (VADs). Drug anticoagulation and the use of biocompatible surfaces, such as coating with heparin, aim to reduce thromboembolism in these patients. Administration of heparin can lead to heparin-induced thrombocytopenia (HIT) type II, mainly through heparin/platelet factor 4 (PF4) antibodies. We assessed the presence of PF4 antibodies in VAD thrombi of patients with heparin-coated VADs and HIT II.nnnMETHODSnThrombi (n = 6) were obtained from the replaced Excor ventricles of patients with HIT II after biventricular VAD implantation (Excor Adult; Berlin Heart, Germany). Excor ventricles were changed after clinical examination and suspicion of thrombi in the polyurethane valves. Expression of PF4- antibodies was assessed with the use of a polyclonal rabbit antibody (anti-PF4 antibody; Abcam, USA). Expression was assessed by 2 independent observers.nnnRESULTSnBiopsies of all thrombi showed an extreme positive immunoreaction for PF4. No differences between the different thrombi and localization (left/right Excor ventricle) were observed. The thrombi were organized, without lamination of fibrin and cellular layers.nnnCONCLUSIONSnPlatelet surface expression of PF4 in the thrombi reflects HIT antigen presentation. The physical relationship between the PF4-positive thrombi and the heparin-coated surface suggests that onset of HIT II could be influenced by the immobilized heparin coating.

Type A Intramural Hematoma Often Turns Out To Be a Type A Dissection

BACKGROUNDnThe management of type A intramural hematoma (IMH) is controversial. Although most Western countries still recommend immediate surgical repair, some centers in Asia have shown good results recently with medical treatment alone. Here, we present a case of type A IMH which was discovered during the operation to be a thrombosed type A dissection.nnnCASE REPORTnAn 83-year-old female patient presented with acute chest pain. After diagnostic exclusion of myocardial infarction, computed tomography was performed, which showed an IMH from the ascending to the descending aorta. No intimal flap could be detected. The ascending aorta was replaced surgically with a prosthesis. During the operation, we found a ruptured intimal plaque, which had caused dissection of the aorta with thrombosis of the false lumen. The true diagnosis-thrombosed type A dissection and not IMH-was revealed neither by computed tomography nor by transesophageal echocardiography.nnnCONCLUSIONnType A IMH should still be treated with immediate surgical repair because in many cases it turns out to be thrombosed type A dissection.

Modified Implantation Technique for the Berlin Heart EXCOR Assist Device in Adults

The Berlin Heart EXCOR ventricular assist device provides pulsatile ventricular assistance. It can be used for univentricular or biventricular support. However, pre-, intra-, and postoperative complications (e.g., bleeding, anastomotic insufficiency) are frequent. We present herein a detailed description of our modified implantation technique in order to facilitate further clinical use of the system.

Impact of donor and recipient sex on outcome.

Purpose of reviewThe impact of donor and recipient sex on outcome after heart transplantation (HTx) is discussed controversially. Therefore, the recent findings in this field were reviewed. Recent findingsThe combination male recipient/female donor increases the risk for early mortality, whereas other sex constellations yield similar outcomes after HTx. In the long-term follow-up, survival of female recipients is superior, especially in the combination female recipient/female donor. Female recipients of male donor hearts are more susceptible to cellular rejection episodes. Their superior long-term outcome, however, is not affected by that. SummarySex matching in HTx, although desirable, is not always possible without prolonging waiting times for the desired donor heart. The combination female donor–male recipient should be evaluated with caution.

Heparin-induced thrombosis without thrombocytopenia causing fulminant pulmonary embolism after off-pump coronary artery bypass grafting.

Heparin-induced thrombocytopenia (HIT) is a rare immune-mediated complication of heparin administration. A potentially life-threatening complication, HIT is difficult to diagnose in patients in the intensive care unit after cardiac surgery because there can be multiple reasons for thrombocytopenia. Moreover, immune-mediated platelet consumption may be masked by reactive thrombocytosis, which is common in the typical postoperative course after cardiac surgery. We report the case of a 57-year-old male patient who developed fulminant pulmonary embolism following heparin-induced thrombosis without thrombocytopenia after off-pump coronary artery bypass surgery.

Five-year experience using the Lung Allocation Score: the Munich Lung Transplant Group

OBJECTIVESnThe Lung Allocation Score (LAS) was implemented in Germany on 10 December 2011 after demonstrating favourable outcomes in the USA since its introduction in 2005. There are only limited and short-term data on the effect of the LAS on lung transplantation programmes in Germany. The purpose of this study was to analyse our 5-year single-centre experience with the LAS within the influential area of the Eurotransplant Foundation (ET).nnnMETHODSnAfter implementation of the LAS until December 2016, 294 patients underwent a single-lung transplantation or a bilateral sequential lung transplantation for end-stage lung disease at our centre. Patients were divided into 4 groups according to their primary diagnosis. The Kaplan-Meier analyses of survival probabilities were performed to compare types of transplant procedures, underlying diagnoses and the LASs at the time of transplantation. Waitlist characteristics, transplant procedures and up to 5-year post-transplant outcomes were analysed.nnnRESULTSnThe proportion of lung transplants performed for interstitial lung disease increased over time from 27% in 2012 to 54% in 2016 (Pu2009=u20090.056). At the same time, the proportion of patients with chronic obstructive pulmonary disease undergoing lung transplantation declined over the 5-year period, i.e. from 29% in 2011 to 19% in 2016 (Pu2009=u20090.029). Overall waiting times of transplanted patients were approximately 200u2009days and did not markedly change over time. There was an increasing proportion of chronic obstructive pulmonary disease patients on the waitlist from 41% in 2011 to 51% in 2016 (Pu2009=u20090.51). Outcomes were independent of the underlying disease entity or the LAS. Bilateral sequential lung transplantation was associated with a better long-term survival probability when compared with a single-lung transplantation (Pu2009<u20090.001).nnnCONCLUSIONSnOur centre-specific 5-year experience confirms previous findings demonstrating that the LAS is a well-established tool for the selection of lung transplant candidates, respecting urgency and prognostic transplant benefit in a disease-specific manner. However, the LAS did not shorten overall waiting times in transplanted patients. Further long-term and multicentre data with respect to differential transplant centre activities have to be gathered for further evaluation.

Interdisciplinary three-step strategy to treat aortic stenosis and coronary artery disease in a patient with end-stage chronic obstructive pulmonary disease

Background Valvular aortic stenosis is a common disease in the elderly, often in multimorbid patients. It is often associated with coronary artery disease and peripheral artery disease. In this situation, the risk of conventional open-heart surgery is too high, and other treatment strategies have to be evaluated. Case report A 79-year-old female patient with severe aortic stenosis, coronary artery disease and end-stage chronic obstructive pulmonary disease suffering from dyspnea at rest and permanently dependent on oxygen was treated in three steps. Firstly, her pulmonary infection was treated with antibiotics for 7 days. Then, the left anterior descending artery was stented (bare-metal stent). In the same session, valvuloplasty of the aortic valve was performed. She was sent to rehabilitation to improve her pulmonary condition and took clopidogrel for 4 weeks. Finally, she underwent transapical aortic valve replacement. She was released to rehabilitation on postoperative day 12. Conclusion A combination of modern interventional and minimally invasive surgical techniques to treat aortic stenosis and coronary heart disease can be a viable option for multimorbid patients with extremely high risk in conventional open-heart surgery.