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Ann Thorac Surg 2003;75:1469-1475
© 2003 The Society of Thoracic Surgeons
a Department of Thoracic and Cardiovascular Surgery, Heart Center North Rhine-Westphalia, Ruhr University of Bochum, Bad Oeynhausen, Germany
b Department of Surgery, The Milton S. Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania, USA
Accepted for publication June 7, 2002.
* Address reprint requests to Dr El-Banayosy, Herzzentrum NRW, Klinik für Thorax- und Kardiovaskularchirurgie, Georgstr 11, D-32545 Bad Oeynhausen, Germany
e-mail: abanayosy{at}hdz-nrw.de
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Abstract |
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 Top Abstract IntroductionMaterial and methodsResultsCommentAcknowledgmentsReferences |
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METHODS: Since October 1999, 6 male patients between 55 and 69 years of age (mean 65 ± 6 years) have received the device at our center; all were in New York Heart Association functional class IV and ineligible for heart transplantation.
RESULTS: All surgical procedures were uneventful, with a timely extubation in 5 of 6 patients. Duration of support was 17 to 670 (mean 245 ± 138) days, with a cumulative experience of 4.5 years. Three patients recovered to be discharged from hospital under support and are long-term survivors. Three patients died 17, 31, and 112 days after implantation from multiple organ failure without being discharged to their homes. The survival rate is 50% after 18 months. There were no major system-related problems or any device-related infections, which are otherwise commonly found among vertricular assist device patients.
CONCLUSIONS: Our preliminary experience demonstrates the reliability and efficacy of the different parts of the system. Nevertheless, further sophistication is needed to reduce the size of its components, which so far still constitutes a limiting factor.
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Introduction |
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TopAbstractIntroductionMaterial and methodsResultsCommentAcknowledgmentsReferences |
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One step towards permanent support is the Arrow LionHeart LVD 2000 left ventricular assist device (Arrow International), the first fully implantable destination therapy ventricular assist system. The aim of the present study is to describe 2 years of clinical experience with this device, which was implanted for the first time worldwide at our center in October 1999.
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Material and methods |
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TopAbstractIntroductionMaterial and methodsResultsCommentAcknowledgmentsReferences |
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The system controller is housed within a titanium case with a set of rechargeable batteries providing emergency power supply and allowing uncoupling of the external power supply for approximately 30 minutes at a time. The controller regulates power from the external power supply and provides motor control and telemetry. The control system is dependent on continual monitoring of end-diastolic volume, thus determining the filling volume of the pump. Pumping characteristics are subsequently adjusted to ensure complete filling of the pump, which is achieved by altering pump speed. An ongoing history of support characteristics is recorded and may be intermittently accessed by using the telemetry module that is included as part of the control system.
External DC power is converted to an alternating current, which, by induction coupling, allows transcutaneous transmission of energy to an implanted secondary coil. This energy source is subsequently rectified to a DC that, in turn, drives the motor and its associated electronic hardware.
The gas-filled compliance chamber consists of a circular polymer sac and an attached subcutaneous port infusion system. Intermittent monitoring of system pressures via the infusion port allows introduction or removal of air from the system, which is accomplished through this same port.
The external components include the power pack, power transmitter, charger with battery packs, telemetry wand, system monitor, and various power supply options (Fig 3A, 3B). These components ensure safe, continuous operation of the pump with enough flexibility to allow patients to return to a normalized lifestyle after discharge from the hospital. The external power coil allows the patient to be completely uncoupled for short periods of time.
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A right sixth-intercostal-space anterior transverse incision is used to fashion a subcutaneous pocket for the secondary coil, and the coil is inserted. The electrical connections from the pump and the secondary coil are tunneled to the electronics package and connected. There are no particular requirements for the sequence in which electrical connections are made. Connectors can safely be removed and reattached while the system is running.
The pleural space is opened, the variable volume compliance chamber is inserted, and its inlet/outlet tube is tunneled to the pump housing and connected. A 2-cm incision over the lower anterior left chest is used to fashion a subcutaneous tissue pocket for the infusion port. This is inserted and tunneled into the compliance chamber.
The primary coil is applied and the device is activated while cardiopulmonary bypass is gradually discontinued. The system is generally started at 10 bpm so that the surgical connections may be checked for leaks and the outlet graft may be probed for air. Increases in rate are achieved manually, as cardiopulmonary bypass is withdrawn, until the minimum automatic rate of 50 bpm is reached. Thereafter, the pump rate is controlled automatically according to filling, as described above.
Patients and methods
Being one of six centers participating in the CUBS trial, we have enrolled 6 patients who have received a LionHeart since October 1999. Major inclusion criteria of this study are left ventricular ejection fraction <30% within 90 days before enrollment, heart failure of at least 6 weeks’ duration, New York Heart Association (NYHA) functional class IV heart failure, ineligibility for heart transplantation, and peak oxygen consumption by cardiopulmonary exercise testing <14 cc/kg/min. Major exclusion criteria are body surface area <1.5 m2, active systemic infection, any contraindication to anticoagulation, including allergy to heparin, and presence of a prosthetic heart valve, except for aortic homograft or stentless valves.
Our 6 patients, all of them male, were between 55 and 69 years of age (mean 65 ± 6 years), had a history of cardiomyopathy (dilated n = 2, ischemic n = 4), and were ineligible for heart transplantation because of age (n = 3), malignancy (n = 2), or systemic lupus erythematosus (n = 1). All patients were in NYHA functional class IV with maximum heart failure medication. Five patients had been under inotropic support, and 1 patient additionally had intraaortic balloon pumping.
Preimplantation laboratory parameters were as follows: creatinine 1.2 to 1.5 (1.3 ± 1.3) mg/dL, BUN 47 to 126 (75 ± 34) mg/dL, total bilirubin 0.6 to 2.3 (1.3 ± 0.6) mg/dL (Table 1).
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Antibiotic protocol
Our antibiotic and infection management protocol is the same as with other assist devices, and consists of a short-term prophylactic administration of cefazolin (3 x 2 g daily) in all patients until all drains are removed. If they develop systemic signs of infection, they are given antibiotics according to the antimicrobial sensitivity test, starting with flucloxacillin 8 to 12 g daily. If methicillin-resistant Staphylococcus aureus is present, therapy is started with vancomycin, with a target serum level of 20 to 40 mg/L. In case the infection cannot be controlled by this antibiotic regime, rifampicin (10 mg/kg body weight daily) according to liver and renal function is administered additionally for at least 4 weeks.
Out-of-hospital drug therapy
In addition to anticoagulation described above, the patients receive ß-blockers, ACE inhibitors, and spironolactone in order to achieve an optimal heart rate <90 bpm and to reduce mean diastolic blood pressure to about 90 mm Hg. A previous amiodarone medication was continued after implantation.
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Results |
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TopAbstractIntroductionMaterial and methodsResultsCommentAcknowledgmentsReferences |
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In spite of the special feature of the system, which was that several components had to be implanted in different locations, there was no surgical difficulty with regard to the adaptation of these components during implantation. All surgical procedures were uneventful without operative mortality. All patients except 1 could be extubated within 72 hours. Duration of support was 17 to 670 (mean 245 ± 138) days, with a cumulative experience of 4.5 years. Three patients recovered, fulfilled our discharging criteria published elsewhere [3], and are long-term survivors. Three patients died 17, 31, and 112 days after implantation from multiple organ failure without being discharged to their homes. The survival rate in our collective is 50% after 18 months (Fig 4). The incidence of complications is detailed in Table 2.
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There were no major problems related to the compliance chamber, which proved to operate efficiently. To maintain the optimal chamber pressure of +3 to +5 mm Hg, 50 to 70 mL air had to be injected into the chamber every 2 to 6 weeks depending on the ventilatory status of the patient. The comparison between a patient with and without ventilation shows that in a patient under ventilation, the compliance chamber needs less volume addition to achieve the target pressure than in a patient without ventilation (see Fig 5a, 5b). The mean air loss within the chamber was 3.0 ± 1.4 mL/day.
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Comment |
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TopAbstractIntroductionMaterial and methodsResultsCommentAcknowledgmentsReferences |
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The LionHeart was implanted for the first time worldwide in October 1999 at our center. Since then, 6 patients received the device with a mean duration of support of 245 days, thus being a unique experience in an initial device trial. With a survival rate of 50% at 18 months, our early results have proved the device to be an effective and reliable means of supporting this critically ill patient cohort. There were no major device-related problems and no pump stops; the transcutaneous energy transmission system (TETS) as well as the compliance chamber, being new components of mechanical circulatory support systems, have turned out to be safe and reliable so far. In 1 patient, the battery had to be replaced after 22 months. The manufacturer of the device is currently developing a new battery with an extended durability and an improved capacity. In another patient, a connector/controller problem occurred with the pump operating at a reduced rate without being hazardous to the patient. The controller was replacement and the patient could be discharged home again.
Device-related infections, which are commonly associated with the application of other ventricular support systems, were not observed during our LionHeart experience, which, however, is still limited due to the low number of patients. Based on our experience with 6 patients treated according to the same antibiotic regime as other long-term ventricular assist device patients, the degree of implantability of a device seems to be the decisive factor in the development of this complication. The lack of infectious complications markedly improves the quality of life.
Neurological problems occurred in only 1 patient, who had a stroke on postoperative day (POD) 35 with subsequent hemiparesis. He suffers from diabetes mellitus and had preoperative carotid artery plaques, which might have played a role in the neurological events. His condition has improved and he has lived on the device for 2 years without further deterioration.
Temporary moderate hemolysis (plasma-free hemoglobin of 50 mg/dL) was found in 3 patients with an increased blood flow (pump in full-to-empty mode). After switching to the fixed rate mode, this complication did not occur. The device software was changed subsequently by modifying (ie, decelerating) pressure development within the pump. After returning to the automatic mode again later, hemolysis was not observed any more.
Two patients had early ventricular tachycardias 2 and 4 weeks after surgery. In both patients, they could be managed by cardioversion; 1 patient needed antiarrhythmic therapy with amiodarone and ß-blockers to maintain a stable rhythm.
The third patient had to undergo bowel surgery for an intestinal mass 43 days after device implantation. During surgery, the pump had to be moved slightly in the median direction within the pocket, resulting in a kinking of the outflow graft later. The kinking led to a low pump output and temporary hemolysis and had to be corrected surgically. The patient is now doing well at home.
There were three in-hospital fatalities. Our second patient initially recovered and could be moved to the ward on POD 36. However, he had to be referred to the intensive care unit again for a respiratory infectious complication followed by retroperitoneal bleeding and multiple organ failure, from which he died on POD 112. Our fourth patient died on POD 17 after a nonsurgical bleeding complication with subsequent nonocclusive mesenteric ischemia and multiple organ failure. Our last patient died on POD 31 after a bleeding complication and multiple organ failure.
One limiting factor of the present study is the low number of patients enrolled due to very stringent inclusion criteria. However, it has been shown that for these critically ill patients, it is very difficult to recover from the enormous surgical trauma. If these criteria are slightly loosened, possibly less morbid patients may be accepted for this intervention.
Nevertheless, with the application of this new device, the incidence of infections could be markedly reduced compared with various other reports [6–10]. The lack of major events affecting pump function proves the reliability of the system. Nevertheless, the size of the system components still constitutes a limiting factor. A new version of the LionHeart is currently being developed that includes a 50% smaller controller and provides an extended battery capacity.
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Acknowledgments |
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TopAbstractIntroductionMaterial and methodsResultsCommentAcknowledgmentsReferences |
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References |
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TopAbstractIntroductionMaterial and methodsResultsCommentAcknowledgmentsReferences |
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  B. Hansky, J. Vogt, A. Zittermann, H. Guldner, J. Heintze, U. Schulz, D. Horstkotte, G. Tenderich, and R. Korfer Cardiac resynchronization therapy: long-term alternative to cardiac transplantation? Ann. Thorac. Surg., February 1, 2009; 87(2): 432 - 438. [Abstract] [Full Text] [PDF]
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S. Aggarwal, F. Cheema, M. C. Oz, and Y. Naka Long-Term Mechanical Circulatory Support Card. Surg. Adult, January 1, 2008; 3(2008): 1609 - 1628. [Full Text]
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