Ann Thorac Surg 1997;64:839-841
© 1997 The Society of Thoracic Surgeons
Case Report
Replacement of an Intracorporeal Left Ventricular Assist Device
Jonathan L. Skinner, MD,
Robert C. Bourge, MD,
James K. Kirklin, MD,
David C. McGiffin, MD,
William L. Holman, MD
Divisions of Cardiothoracic Surgery and Cardiovascular Diseases, University of Alabama at Birmingham, Birmingham, Alabama
Accepted for publication April 11, 1997.
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Abstract
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An intracorporeal left ventricular assist device was placed as a bridge to cardiac transplantation in a 51-year-old man after an acute myocardial infarction. After 126 days of support, the left ventricular assist device malfunctioned. The pump, which had a tear in its pneumatic drive line, was successfully replaced.
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Introduction
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Ventricular assist devices (VADs) have been used with success as a bridge to cardiac transplantation [1, 2], and they are now entering trials as permanently implanted pumps. These mechanical devices are subject to occasional failure that requires pump replacement. The following case report illustrates the urgent surgical replacement of an intracorporeal left VAD (LVAD) and briefly reviews the multiinstitutional experience with the replacement of one pump design.
A 51-year-old man was referred to this institution for cardiac transplant evaluation 4 days after an acute anterolateral infarction. The patient's medical history included tobacco use and hypercholesterolemia. The physical examination on admission showed a sedated, intubated man with a femoral intraaortic balloon pump set at a counterpulsation ratio of 1:1. His systemic blood pressure was 90/50 mm Hg and the rhythm was sinus tachycardia at 130 beats/min. The cardiac index was 2.9 L • min-1 • m-2 with a pulmonary capillary wedge pressure of 16 mm Hg. Inotropic medications included dopamine and dobutamine. The remainder of the physical examination was unremarkable.
A transthoracic echocardiogram showed an ejection fraction of 0.10. There was evidence of apical thrombus and akinetic segments of the left ventricle consistent with a large anterolateral infarction. Two days after admission, the patient's condition worsened and a pneumatically driven LVAD (HeartMate IP LVAD; Thermo Cardiosystems, Inc, Woburn, MA) was implanted.
One hundred twenty-six days after LVAD placement, an acute fall in pump output was noted in association with a need for frequent venting of the system. A tear at the junction of the pump housing and pneumatic drive line was suspected. The patient was taken to the operating room. He was placed on cardiopulmonary bypass with femoral venous and arterial cannulation. A sternotomy was performed, then the anterior surface of the heart and the left VAD were dissected free. Complete separation of the pneumatic drive line from the pump housing was found (Fig 1
). At this point, another venous cannula was placed in the right atrium to augment blood flow provided by the cannula previously placed via the femoral vein.
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Fig 1. . Photograph of the explanted pump housing. Note the complete separation of the pneumatic drive line (not shown) at the connection to the pump housing (arrow). The electrical connection to the Hall effect switch was not disrupted.
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During a period of hypothermic cardioplegic arrest, the Dacron outflow conduit was disconnected from the pump housing and the venous inflow cannula to the VAD was removed from the silicone collar in the left ventricular apex. The pump housing was removed from the operative field. A new percutaneous exit site for the drive line was created, then a new pump and inflow conduit were placed in the preperitoneal space that was created at the patient's initial implant operation. The Dacron outflow graft was reconnected to the pump housing, the heart was reperfused, and the VAD was deaired in routine fashion. After completion of deairing and reperfusion, automatic pump cycling was initiated with the heart in sinus rhythm. Cardiopulmonary bypass was discontinued, the bypass cannulas were removed, and the incisions were closed. The patient's second postoperative convalescence was unremarkable.
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Comment
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Ventricular assist devices are an effective treatment for profound circulatory failure and have been used successfully as a bridge to cardiac transplantation [1–3]. Studies are now underway to evaluate LVADs as chronically implanted devices used as an alternative to medical therapy in patients with end-stage heart disease. Ventricular assist device malfunction may occur that requires device replacement; however, there is little published information describing the methods and results of this procedure [4]. Note that most device malfunctions are related to problems with external components (eg, external device control systems, pneumatic drivers). These external components are easily exchanged and the implanted pump remains in place.
Corporate records describing the multicenter experience with the Thermo Cardiosystems HeartMate pneumatic (model IP) and electric (model VE) LVAD show that 22 HeartMate pumps have been replaced for a variety of reasons including infection; the need for long-term outpatient support (ie, pneumatic to electric LVAD replacement), and a variety of malfunctions including perforated inflow conduits and pneumatic drive line tears. Of the 10 patients who underwent pneumatic-to-pneumatic LVAD replacements, 1 (10%) remains on VAD support, 6 (60%) survived to cardiac transplantation, and 3 (30%) died. Of the 8 patients who had electric-to-electric LVAD replacements, 2 (25%) continue on VAD support and 6 (75%) have survived to transplantation. Of the 3 patients who had electric-to-pneumatic LVAD replacements, 2 (67%) have survived to transplantation and 1 (33%) died. The only patient undergoing pneumatic-to-electric LVAD replacement continues on VAD support. Overall, of the total 22 HeartMate LVAD replacements, 18 patients (82%) survived to transplantation or continue on VAD support, and 4 patients (18%) died without transplantation (personal communication; Victor L. Poirier, Thermo Cardiosystems, Inc, Woburn, MA).
This case illustrates a technique for replacing a malfunctioning intracorporeal LVAD. Continually improving reliability of implanted devices is expected to make such operations increasingly less common. However, a need will remain for occasional replacement of malfunctioning devices as well as replacement of chronically implanted devices that reach their anticipated end-of-life after years of service. The results to date with HeartMate replacements in bridge to transplantation patients suggests that intracorporeal pump replacement is feasible, and that this procedure has a reasonably low associated mortality.
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Acknowledgments
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This work was performed during Dr Holman's tenure as an Established Investigator for the American Heart Association.
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Footnotes
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Address reprint requests to Dr Holman, Department of Surgery, University of Alabama at Birmingham, University Station, Birmingham, AL 35294-0007 (e-mail: wholman{at}holman.cvsr.uab.edu).
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References
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- Farrar DJ, Hill JD. Recovery of major organ function in patients awaiting heart transplantation with Thoratec ventricular assist devices. J Heart Lung Transplant 1994;13:1125–32.[Medline]
- Frazier OH, Rose EA, McCarthy PM, et al. Improved mortality and rehabilitation of transplant candidates treated with a long-term implantable left ventricular assist system. Ann Surg 1995;222:327–38.[Medline]
- Massad MG, McCarthy PM, Smedira NG, et al. Does successful bridging with the implantable left ventricular assist device affect cardiac transplantation outcome? J Thorac Cardiovasc Surg 1996;112:1275–83.[Abstract/Free Full Text]
- Goldstein DJ, El-Amir NG, Ashton RC, et al. Fungal infections in left ventricular assist device recipients: incidence, prophylaxis, and treatment. ASAIO J 1995;41:873–5.[Medline]
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Abstract
Introduction
