Interact CardioVasc Thorac Surg 2009;8:168-170. doi:10.1510/icvts.2008.187567
© 2009 European Association of Cardio-Thoracic Surgery
Case report - Cardiopulmonary bypass |
Possibilities and limitations of a miniaturized long-term extracorporeal life support system as bridge to transplantation in a case with biventricular heart failure
Daniele Camboni*,
Alois Philipp,
Stephan Hirt and
Christoph Schmid
Department of Cardiothoracic Surgery, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany
Received 4 July 2008;
received in revised form 14 September 2008;
accepted 17 September 2008
*Corresponding author. Tel.: +49-(0)941-9449801; fax: +49-(0)941-944-9802.
E-mail address: dcamboni{at}arcor.de (D. Camboni).
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Abstract
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In cardiac surgery extracorporeal life support systems (ECLS), also known as extracorporeal membrane oxygenation systems (ECMO), are often placed in case of postcardiotomy shock, until the patient's myocardial pump function recovers. Patients under ECLS are typically intubated and immobilized. We present a 57-year-old man suffering from severe ischemic cardiomyopathy in biventricular failure and intractable cardiogenic shock, who was supported with a miniaturized cardiopulmonary bypass system (MECC®) installed as venoarterial ECLS for 37 days. The patient was fully awake, spontaneously breathing, and practicing exercise in bed during life support for four weeks. He then required intubation for pneumonia, but later underwent successful transplantation. In conclusion, this case demonstrates that ECLS with miniaturized heart-lung machines offer the possibility of prolonged and safe support, ideal as a bridge to decision in patients with cardiogenic shock. On the other side, this report also indicates that ECLS is not recommended as a bridge to transplantation on a routine basis.
Key Words: Extracorporeal membrane oxygenation; Cardiopulmonary bypass; Transplantation
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1. Introduction
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An extracorporeal life support system (ECLS) is frequently the last option to provide both cardiac and respiratory support in patients with severe cardiopulmonary compromise [1]. In contrast to many other circulatory support systems, ECLSs offer several advantages like simple percutaneous cannula placement in emergency situations for example [2]. In addition, ECLS treatment offers time to assess the possibility of heart transplantation. For the latter purpose ECLS therapy is considerably less expensive in comparison to other forms of mechanical support [3]. ECLS has also several disadvantages that limit its applicability to serve as bridge to heart transplantation on a routine basis, including hemolysis, bleeding, infection, and especially the impossibility to adequately mobilize the patient. Accordingly, ECLS therapy is usually applied only for a few hours or days in adults. In this report, we present an interesting case dealing with a patient suffering from an intractable cardiogenic shock, who was supported with a miniaturized extracorporeal circulation system (MECC®, PLS Maquet, Germany) as venoarterial ECLS for five weeks.
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2. Case
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A 57-year-old male (height 170 cm, body weight 70 kg) suffering from ischemic cardiomyopathy with severely reduced left ventricular function was referred to our institution for transplant evaluation. During coronary angiography, a spontaneous thrombotic occlusion of the right coronary artery with a subsequent intractable cardiogenic shock occurred. After mechanical resuscitation and borderline stabilization with high doses of inotropes and an intraaortic counterpulsation, a venoarterial ECLS using a MECC® system was installed. Venous drainage was obtained by a 23 French cannula (Bio-Medicus®, Medtronic, USA), which was placed percutaneously via the left femoral vein into the right atrium. The arterial cannula (Aortic cannula, Berlin Heart, Germany) was fixed to the ascending aorta after median sternotomy to achieve maximal flow rates, and because the patient's femoral arteries were extensively calcified. Anticoagulation was managed with heparin, keeping the partial thromboplastine time (PTT) between 60 and 80 s. Platelet aggregation was inhibited with aspirin guided by aggregrometry (PAP4 Aggregometer, Mölab®, Germany) on a daily basis [4]. The patient was extubated 36 h after surgery without neurological impairment. Despite clinical improvement the patient still required ECLS therapy for circulatory support due to a predominantly right-sided biventricular failure and insufficient oxygenation. The evaluation for cardiac transplantation was completed and the patient listed for heart transplantation. However, because of an excellent postoperative course with a fully awake patient we continued our initial therapy regime. In addition, the patient did not provide consent for another form of mechanical support.
As a result we expanded the physical rehabilitation program with intermittent positive airway breathing as well as with a special ergometer training adapted for bedridden individuals during ongoing life support (Fig. 1). The intermittent positive airway breathing was important to prevent atelectasis of the lung. The ergometer exercise was performed with a workload of up to 30 watt, intermittently monitoring blood gas parameters. During exercise, the pump flow of the ECLS was slightly increased from 4.3–5.0 l/min, and the supplied oxygen (FiO2) to the oxygenator was increased from 80–100% to meet the higher demands. The goal was to maintain an aerobic training with a pO2 >60 mmHg and normal lactate levels, while the SvO2 should remain near 50%. After terminating physical activity the pO2 normalized again, and the augmented ECLS performance was stepwise reduced to the initial setting. By calculating the gas transfer on a daily basis, we were able to discriminate the time point to exchange the oxygenator, which was accomplished four times in total .
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Fig. 1. The patient during ECLS support, being fully awake, spontaneously breathing, and practicing with an ergometer. C, console; P, centrifugal pump; O, membrane oxygenator.
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After four weeks of uneventful ECLS therapy with daily physical rehabilitation, the patient developed several episodes of shortness of breath, and required an increased inotrope support as well as an augmented ECLS flow. In the chest X-ray bilateral pneumonia became evident, ultimately requiring intubation and mechanical ventilation after 30 days of ECMO. On day 37, a suitable donor organ was available and a successful cardiac transplantation was performed. The postoperative course was complicated by renal failure and recurrent infections, mandating a prolonged hospital stay. Ultimately the patient recovered nearly totally and he was transferred to a rehabilitation hospital.
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3. Comment
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ECLS is a well established technology that provides cardiopulmonary support. The presented patient was supported with a miniaturized extracorporeal system applied as a venoarterial ECLS. Miniaturized systems are increasingly used in cardiac surgery, as they appear to be less harmful to end-organ function in contrast to a standard heart-lung machine or standard ECLS/ECMO [5]. Thus, the technical advances seem to allow an extended use even in adults.
However, ECLS therapy for longer intervals provides a major concern as patients cannot be mobilized. Our patient was supported for 37 days. The patient was fully awake and practising even ergometer training for nearly a month. We did not observe difficulties with regard to cannula dislocation under physical activity. It was decided to continue ECLS therapy as bridge to transplantation, due to the stable and impressive postoperative course.
Adult patients on ECLS are rarely bridged to transplantation. In case of failed weaning from ECLS, it is mostly recommended to implant a long-term mechanical support device [6]. Even though some colleagues noticed unsatisfied survival rates in the bridge-to-bridge population and recommend primary ventricular assist device implantation [7]. Despite rather long waiting times for patients on the waiting list the strategy of bridge to transplantation with a miniaturized ECLS should remain an exception. Regardless of maximal efforts for patient rehabilitation we encountered typical problems related to long-lasting ECLS therapy. The inadequate ventilation and consecutive restricted perfusion of the lung during ECMO support is probably the greatest disadvantage apart from full mobilization.
In conclusion, this case demonstrates that ECLS with miniaturized heart-lung machines offer the possibility of prolonged and safe support ideal as a bridge to decision in patients with cardiogenic shock. On the other side this report also indicates that ECLS is not recommended as a bridge to transplantation on a routine basis.
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Graph 1. Blood flow via the ECLS, oxygen transfer and carbon dioxide elimination by the oxygenator over five weeks of support.
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References
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- Younger JG, Schreiner RJ, Swaniker F, Hirschl RB, Chapman RA, Bartlett RH. Extracorporeal resuscitation of cardiac arrest. Acad Emerg Med 1999;6:700–707.[Medline]
- Nichol G, Karmy-Jones R, Salerno C, Cantore L, Becker L. Systematic review of percutaneous cardiopulmonary bypass for cardiac arrest or cardiogenic shock states. Resuscitation 2006;70:381–394.[CrossRef][Medline]
- Pagani FD, Lynch W, Swaniker F, Dyke DB, Bartlett R, Koelling T, Moscucci M, Deeb GM, Bolling S, Monaghan H, Aaronson KD. Extracorporeal life support to left ventricular assist device bridge to heart transplant: A strategy to optimize survival and resource utilization. Circulation 1999;100(Suppl_19):206–210.
- Philipp A, Müller T, Bein T, Foltan M, Schmid FX, Birnbaum D, Schmid C. Inhibition of thrombocyte aggregation during extracorporeal lung assist: a case report. Perfusion 2007;22:293–298.[Abstract/Free Full Text]
- Wiesenack C, Liebold A, Philipp A, Ritzka M, Koppenberg J, Birnbaum DE, Keyl C. Four years' experience with a miniaturized extracorporeal circulation system and its influence on clinical outcome. Artif Organs 2004;28:1082–1088.[CrossRef][Medline]
- Hoefer D, Ruttmann E, Poelzl G, Kilo J, Hoermann C, Margreiter R, Laufer G, Anretter H. Outcome evaluation of the bridge-to-bridge concept in patients with cardiogenic shock. Ann Thorac Surg 2006;82:28–33.[Abstract/Free Full Text]
- Magliato KE, Kleisli T, Soukiasian HJ, Tabrizi R, Coleman B, Hickey A, Czer LS, Blanche C, Cheng W, Fontana GP, Kass RM, Raissi SS, Trento A. Biventricular support in patients with profound cardiogenic shock: a single center experience. ASAIO J 2003;49:475–479.[Medline]
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Abstract
1. Introduction