Interact CardioVasc Thorac Surg 2009;8:682-683. doi:10.1510/icvts.2008.199208
© 2009 European Association of Cardio-Thoracic Surgery
Case report - Assisted circulation |
The Impella® LP 5.0 as a bridge to long-term circulatory support
Gordan Samoukovica,
Cristian Rosua,
Nadia Giannettib and
Renzo Cecerea,*
a Division of Cardiothoracic Surgery, McGill University Health Center, 687 Pine Avenue West, Montreal, Quebec H3A 1A1, S-8.44, Canada
b Division of Cardiology, McGill University Health Center, 687 Pine Avenue West, Montreal, Quebec H3A 1A1, M4, Canada
Received 24 November 2008;
received in revised form 5 February 2009;
accepted 9 February 2009
*Corresponding author. Associate Professor of Surgery, McGill University, Surgical Director, Heart Failure and Thoracic Transplant Program, Director, Mechanical Cardiac Assist Program. Tel./fax: +1 514 934-1934.
E-mail address: renzo.cecere{at}muhc.mcgill.ca (R. Cecere).
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Abstract
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Multi-organ failure (MOF) secondary to bi-ventricular cardiac dysfunction is a major therapeutic challenge. In addition to aggressive medical therapy, it frequently requires circulatory support with uni- or bi-ventricular assist devices. The Impella® LP 5.0 is a new microaxial left ventricular assist device (LVAD). Microaxial LVADs have been used for short-term circulatory support in patients with cardiogenic shock due to myocarditis, post coronary artery bypass grafting (CABG), or during high-risk percutaneous coronary interventions (PCI). We present a case of a patient in bi-ventricular failure successfully bridged to permanent circulatory support. Relative merits of this therapeutic approach are outlined and discussed.
Key Words: Congestive heart failure; Mechanical circulatory support; Cardiac transplantation
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1. Introduction>
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When cardiogenic shock proves refractory to medical therapy and intraaortic balloon counterpulsation, mechanical circulatory support with uni- or bi-ventricular assist devices and cardiac transplantation are the remaining options, albeit each with its own limitations and complications. The Impella® LP 5.0, a microaxial LVAD, has been used in Europe for over five years to provide short-term circulatory support in a variety of low cardiac output states and has recently been introduced to North American health care. The device is inserted percutaneously and guided across the aortic valve. The blood from the ventricle is aspirated and ejected into the ascending aorta via the distal and outflow lumina, respectively. Impella® LP 5.0 achieves maximal non-pulsatile flow of 5 l/min while requiring only low anticoagulation. It has been used in patients with acute deterioration of dilated cardiomyopathy, in acute heart failure after myocardial infarction and viral myocarditis [1] as well as for circulatory support after coronary artery bypass grafting [2, 3]. In the presented case, left ventricular support with the Impella® LP 5.0 allowed recovery of severe right ventricular (RV) dysfunction, as well as normalization of end-organ function, permitting safer implantation of a longer-term LVAD as a bridge to cardiac transplantation.
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2. Clinical summary
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A 36-year-old man known for idiopathic dilated cardiomyopathy (DCM) presented with acute deterioration in exercise capacity and severe dyspnea, orthopnea, and paroxysmal nocturnal dyspnea. The patient was known for left lateral hemianopsia from a stroke in 2004. At presentation, investigations revealed a left ventricular ejection fraction (LVEF) of 10% associated with severe diastolic and RV dysfunction, moderate tricuspid regurgitation, and signs of severe liver and kidney dysfunction. Despite aggressive therapy with milrinone (0.5 µg/kg/min), dobutamine (10 µg/kg/min), and phenylephrine (10 µg/min), his systolic blood pressure (sBP) and cardiac index (CI) remained below 100 mmHg and 1.8 l/min/m2, respectively. In context of worsening hypoperfusion, associated with an anion-gap metabolic acidosis and a serum lactate of 6.3 mmol/l, an Impella® LP 5.0 was inserted via a left femoral artery cut-down and advanced across the aortic valve under fluoroscopic guidance. The pump flow was increased to 3.4 l/min yielding a total CI of 2.4–3.0 l/min/m2. Lactic acidosis and INR corrected within 12 h (Fig. 1) while serum liver enzymes and bilirubin peaked at 12–24 h after insertion and then normalized over the following four days (Fig. 2). During circulatory support, LVEF improved to 25%, while systolic pulmonary artery pressure (sPAP), initially at 43 mmHg, decreased to 24 mmHg. At this time, the patient was listed as a transplant candidate. The average pump output was 3.7 l/min at a performance level P8. With stable hemodynamics, supported only by milrinone (0.375 µg/kg/min), and evidence of marked improvement in RV function, and due to the absence of a suitable heart donor secondary to extensive allo-antibodies, on the tenth day of support, the Impella® LP 5.0 was replaced by a longer-term LVAD, the Abiomed AB5000, via a standard median sternotomy on a beating heart without the use of cardiopulmonary bypass, as a bridge to transplantation. This device was chosen for several reasons: (1) the patient's size (52 kg), (2) need for low intraoperative anticoagulation in the context of profound epistaxis while anticoagulated with heparin during the support with the Impella, and (3) anticipation of early transplantation.
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Fig. 1. Variation of serum lactate and INR with time on Impella® LP 5.0 support. Time zero and the arrow represent the times of the Impella insertion and removal, respectively.
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Fig. 2. Variation of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin with time on Impella® LP 5.0 support. Time zero and the arrow represent the times of the Impella insertion and removal, respectively.
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3. Discussion
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When cardiogenic shock proves refractory to medical therapy, mechanical circulatory support and/or cardiac transplantation are the remaining therapeutic options. This paper presents a case of successful treatment of cardiogenic shock due to severe bi-ventricular failure using a microaxial percutaneous LVAD. Circulatory support with this device allowed recovery of RV function as well as improvement in end-organ function and reduction in sPAP. Prior to the introduction of the percutaneous microaxial LVAD in our center, this case would likely have required bi-ventricular mechanical support with conventional paracorporeal pulsatile VADs. Such surgical procedure, in the context of severe multi-organ dysfunction, and complicated by deleterious inflammatory response to CPB, would most likely have been fatal in this case. Instead, in view of expected early transplantation, the Impella® LP 5.0 microaxial device, inserted percutaneously and providing full left ventricular support, avoided any further surgical insult to the right ventricle, allowing its recovery alongside that of end-organs. Thus, bridging to a longer-term device using the Impella® LP 5.0 resulted in the safe implantation of an LVAD in the setting of optimized RV and end-organ function. This observation supports the notion that patients presenting with circulatory collapse and profound bi-ventricular failure can indeed be recovered with an LVAD only, especially when RV failure is partially a consequence of the surgical trauma incurred by the conventional surgical LVAD implantation itself. Further exploration of the role of microaxial VADs in bridging patients with low cardiac output states towards longer-term circulatory support and/or cardiac transplantation is warranted.
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References
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- Garatti A, Colombo T, Russo C, Lanfranconi M, Milazzo F, Catena E, Bruschi G, Frigerio M, Vitali E. Left ventricular mechanical support with the Impella Recover left direct microaxial blood pump: a single-center experience. Artif Organs 2006;30:523–528.[CrossRef][Medline]
- Rossiter-Thornton M, Arun V, Forrest AP, Bayfield MS, Wilson MK. Left ventricular support with the Impella® LP 5.0 for cardiogenic shock following cardiac surgery. Heart, Lung and Circulation 2008;17:243–245.[CrossRef]
- Siegenthaler MP, Brehm K, Strecker T, Hanke T, Nötzold A, Olschewski M, Weyand M, Sievers H, Beyersdorf F. The Impella recover microaxial assist device reduces mortality for postcardiotomy failure: a three-center experience. J Thorac Cardiovasc Surg 2004;127:812–822.[Abstract/Free Full Text]
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Abstract
1. Introduction>