Six Years of Continuous Mechanical Circulatory Support
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《新英格兰医药杂志》
To the Editor: In 2001, a randomized trial comparing a pulsatile left ventricular assist device (LVAD) with medical therapy for end-stage heart failure reported a median survival advantage of 8.5 months for patients receiving the device.1 The patients' quality of life was limited by serious complications related to the LVAD. In 2000, we began a long-term observational study of circulatory support with a new, miniaturized axial-flow pump. At the time, there were important questions about the reliability of a blood pump powered by a rotary electric motor and the effects of diminished pulse pressure over time.
Our first patient was 61 years of age and had idiopathic dilated cardiomyopathy.2 While receiving maximal medical therapy, he was breathless at rest, with pitting edema to the thighs, ulcerated legs, and ascites. His left ventricular ejection fraction was less than 10 percent, with a cardiac index of 1.81 liters per minute per square meter of body-surface area and a maximal oxygen consumption of 5.7 ml per kilogram of body weight per minute during exercise. Cardiac transplantation was not recommended because of renal impairment (creatinine clearance, 38 ml per minute).
The Jarvik 2000 LVAD (Figure 1) was implanted directly into the apex of the dilated ventricle, unloading to the descending thoracic aorta. The performance of this device has been reported previously.3 A novel power-delivery system used a titanium pedestal that was screwed into the skull, so that rigid fixation, rich vascularity, and the absence of fat would help avoid power-cable infection (Figure 1).4 Afterload reduction was continued and warfarin was given, with the dose adjusted to maintain an international normalized ratio of 2.0 to 2.5.
Figure 1. Left Ventricular Assist Device Implanted in the Left Ventricular Apex, with the Power Cable Connected to the Skull Pedestal.
Six years later, the patient is in New York Heart Association class II with the same LVAD, despite very poor underlying left ventricular function. At a pump-rotor speed of 10,000 rpm, the resting cardiac output is 5.5 liters per minute with a mean blood pressure of 70 to 80 mm Hg and a pulse pressure of 10 to 15 mm Hg. The performance of the LVAD has remained unchanged since it was implanted.
The patient has a very active and productive life, including international air travel. Less than 5 percent of the follow-up period has been spent in the hospital. There have been no mechanical or thromboembolic complications, but external components have been exchanged because of wear and tear. The skull pedestal remains infection-free. Staphylococcal septicemia after cauterization for nosebleeds was successfully treated with antibiotics. The LVAD was not infected. Whole-body computed tomography has shown no evidence of thinning of the wall of the aorta, despite the diminished pulse pressure.
This case illustrates the potential long-term durability of the Jarvik 2000 axial-flow blood pump when used as an LVAD in a patient with advanced heart failure.
Stephen Westaby, M.D.
John Radcliffe Hospital
Oxford OX3 9DU, United Kingdom
O.H. Frazier, M.D.
Texas Heart Institute
Houston, TX 77225-0345
Adrian Banning, M.D.
John Radcliffe Hospital
Oxford OX3 9DU, United Kingdom
adrian.banning@orh.nhs.uk
References
Rose EA, Gelijns AC, Moskowitz AJ, et al. Long-term mechanical left ventricular assistance for end stage heart failure. N Engl J Med 2001;345:1435-1443.
Westaby S, Banning AP, Jarvik R, et al. First permanent implant of the Jarvik 2000 Heart. Lancet 2000;356:900-903.
Frazier OH, Myers TJ, Jarvik RK, et al. Research and development of an implantable axial-flow left ventricular assist device: the Jarvik 2000 Heart. Ann Thorac Surg 2001;71:Suppl 3:S125-S132.
Westaby S, Jarvik R, Freeland A, et al. Postauricular percutaneous power delivery for permanent mechanical circulatory support. J Thorac Cardiovasc Surg 2002;123:977-983.
Our first patient was 61 years of age and had idiopathic dilated cardiomyopathy.2 While receiving maximal medical therapy, he was breathless at rest, with pitting edema to the thighs, ulcerated legs, and ascites. His left ventricular ejection fraction was less than 10 percent, with a cardiac index of 1.81 liters per minute per square meter of body-surface area and a maximal oxygen consumption of 5.7 ml per kilogram of body weight per minute during exercise. Cardiac transplantation was not recommended because of renal impairment (creatinine clearance, 38 ml per minute).
The Jarvik 2000 LVAD (Figure 1) was implanted directly into the apex of the dilated ventricle, unloading to the descending thoracic aorta. The performance of this device has been reported previously.3 A novel power-delivery system used a titanium pedestal that was screwed into the skull, so that rigid fixation, rich vascularity, and the absence of fat would help avoid power-cable infection (Figure 1).4 Afterload reduction was continued and warfarin was given, with the dose adjusted to maintain an international normalized ratio of 2.0 to 2.5.
Figure 1. Left Ventricular Assist Device Implanted in the Left Ventricular Apex, with the Power Cable Connected to the Skull Pedestal.
Six years later, the patient is in New York Heart Association class II with the same LVAD, despite very poor underlying left ventricular function. At a pump-rotor speed of 10,000 rpm, the resting cardiac output is 5.5 liters per minute with a mean blood pressure of 70 to 80 mm Hg and a pulse pressure of 10 to 15 mm Hg. The performance of the LVAD has remained unchanged since it was implanted.
The patient has a very active and productive life, including international air travel. Less than 5 percent of the follow-up period has been spent in the hospital. There have been no mechanical or thromboembolic complications, but external components have been exchanged because of wear and tear. The skull pedestal remains infection-free. Staphylococcal septicemia after cauterization for nosebleeds was successfully treated with antibiotics. The LVAD was not infected. Whole-body computed tomography has shown no evidence of thinning of the wall of the aorta, despite the diminished pulse pressure.
This case illustrates the potential long-term durability of the Jarvik 2000 axial-flow blood pump when used as an LVAD in a patient with advanced heart failure.
Stephen Westaby, M.D.
John Radcliffe Hospital
Oxford OX3 9DU, United Kingdom
O.H. Frazier, M.D.
Texas Heart Institute
Houston, TX 77225-0345
Adrian Banning, M.D.
John Radcliffe Hospital
Oxford OX3 9DU, United Kingdom
adrian.banning@orh.nhs.uk
References
Rose EA, Gelijns AC, Moskowitz AJ, et al. Long-term mechanical left ventricular assistance for end stage heart failure. N Engl J Med 2001;345:1435-1443.
Westaby S, Banning AP, Jarvik R, et al. First permanent implant of the Jarvik 2000 Heart. Lancet 2000;356:900-903.
Frazier OH, Myers TJ, Jarvik RK, et al. Research and development of an implantable axial-flow left ventricular assist device: the Jarvik 2000 Heart. Ann Thorac Surg 2001;71:Suppl 3:S125-S132.
Westaby S, Jarvik R, Freeland A, et al. Postauricular percutaneous power delivery for permanent mechanical circulatory support. J Thorac Cardiovasc Surg 2002;123:977-983.