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J Thorac Cardiovasc Surg 2004;127:1203-1204
© 2004 The American Association for Thoracic Surgery
Brief communication |
a Department of Cardiovascular Surgery, The Cardiac Center at the Children's Hospital of Philadelphia, Philadelphia, PA, USA
b Division of Cardiology, The Cardiac Center at the Children's Hospital of Philadelphia, Philadelphia, PA, USA
c Department of Cardiac Anesthesiology, The Cardiac Center at the Children's Hospital of Philadelphia, Philadelphia, PA, USA
Received for publication May 12, 2003; accepted for publication May 16, 2003.
* Address for reprints: J. William Gaynor, MD, Division of Cardiothoracic Surgery, The Children's Hospital of Philadelphia, 34th and Civic Center Blvd, Suite 8527, Philadelphia, PA 19104
Gaynor{at}email.chop.edu
| Because of a potential conflict of interest related to this article on the part of our editors, Dr Richard Jonas served as guest section editor, assigned reviewers, and made editorial decisions or recommendations leading to its acceptance for publication.
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Limited organ availability and prolonged waiting periods for donor hearts has led to the increased use of ventricular assist devices (VADs) as a bridge to transplantation. Recognition of potential myocardial recovery in some reversible cardiac diseases has prompted the use of these devices as a bridge to recovery. Extracorporeal membrane oxygenation is often the only choice for circulatory support in infants and smaller children.1 There are currently no pulsatile VADs approved for use in infants and children in the United States.2 Adult devices such as the Thoratec VAD (Pleasanton, Calif) have been used in some children as a bridge to transplantation.3-5 However, the discrepancy in size between the device and the patient limits its use, particularly if bridge to recovery and removal of the device are planned.
Clinical summary
An 11-year-old previously healthy girl was noted by her grandmother to have an "irregular heartbeat" associated with gasping and agonal respirations while sleeping. Cardiopulmonary resuscitation was initiated, and emergency medical services were called. Ventricular fibrillation was detected and successfully cardioverted to sinus rhythm. After transport to a local hospital, the patient was transferred to The Children's Hospital of Philadelphia. Refractory polymorphic ventricular tachycardia resulted in hypotension and low cardiac output. A lidocaine infusion was begun with poor control of the ventricular ectopy. Echocardiography revealed moderate left ventricular dysfunction with a shortening fraction of 19% and moderate mitral regurgitation. Right ventricular function was preserved. Initiation of inotropic drug therapy resulted in increased ectopy and further deterioration. Because of the isolated left ventricular dysfunction, she was a candidate for left ventricular assist device (LVAD) support.
The patient was taken to the operating room for insertion of a Thoratec LVAD. After cardiopulmonary bypass was initiated, the inflow cannula was positioned in the ventricular apex. An alternative technique would be the use of atrial cannulation for VAD inflow; however, filling of the VAD may be improved with use of apical cannulation. The outflow graft (14 mm) was anastomosed to the ascending aorta. The conduits were de-aired and connected to the device. The patient was weaned from bypass with the device in the volume mode, but later it was converted to the fixed rate mode secondary to inadequate filling of the VAD. The early postoperative course was significant for right ventricular dysfunction requiring aggressive volume resuscitation and support with inotropic drug therapy to optimize preload to the VAD. Amiodarone therapy was initiated because of refractory ventricular ectopy. She was extubated on postoperative day 2. A heparin infusion was used for anticoagulation with no bleeding complications. Mild hemolysis was the only device-related morbidity. Serial echocardiograms demonstrated complete recovery of ventricular function.
The VAD was removed after 13 days of support. The patient was placed on cardiopulmonary bypass. The outflow cannula was stapled with a vascular stapler and divided at the aorta. The cannula was removed from the left ventricular apex, leaving the sewing ring, which was approximated using pledgetted 0 sutures. After the patient was separated from cardiopulmonary bypass, transesophageal echocardiography demonstrated normal ventricular function. Because of persistent ventricular ectopy, despite amiodarone therapy, she underwent implantation of a transvenous defibrillator (internal cardioverter-defibrillator). She was subsequently transitioned to mexiletine therapy. An echocardiogram performed 5 months after discharge demonstrated normal ventricular function. At that time, she had no cardiovascular symptoms. Recurrent ventricular fibrillation has been detected by the internal cardioverter-defibrillator. The cause of the polymorphic ventricular arrhythmia has not been determined.
Discussion
The largest experience with pulsatile VADs in children is in Europe. The Berlin Heart (Berlin, Germany) and the MEDOS (Stolberg, Germany) assist devices are available in a variety of sizes, are suitable for all age groups, and have been used successfully as bridge to recovery and transplant. Neither the Berlin Heart nor the MEDOS VAD are available in the United States, and no pulsatile device is currently approved for use in pediatric patients.
The Thoratec VAD has been used in a small number of children according to the manufacturer's database. As of May 2003, the Thoratec VAD had been used as a bridge to transplant in the United States in 8 children weighing less than 30 kg, but it had not been used in any children as a bridge to recovery. The smallest child was 17 kg.5 Unlike extracorporeal membrane oxygenation, during the period of VAD support patients can be extubated and ambulate, allowing rehabilitation. There is no single solution for pediatric patients requiring mechanical support, but carefully selected pediatric patients may benefit from the Thoratec device as a bridge to transplant recovery. The current case demonstrates that, even in a relatively small child, the device can be removed without adverse effects on ventricular function despite apical cannulation.
References
This article has been cited by other articles:
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  E. D. Blume, D. C. Naftel, H. J. Bastardi, B. W. Duncan, J. K. Kirklin, S. A. Webber, and for the Pediatric Heart Transplant Study Investiga Outcomes of Children Bridged to Heart Transplantation With Ventricular Assist Devices: A Multi-Institutional Study Circulation, May 16, 2006; 113(19): 2313 - 2319. [Abstract] [Full Text] [PDF]
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