THE ROLE OF SURGERY IN HEART FAILURE - PART 10 potx

now achieve 85% 1-year and 65% 2-year survival, which parallels that for hemodialysis in end-stage renal disease. There are other similarities between these end-stage populations. Chronic hemodialysis is only able to sustain life for several years in younger and otherwise healthy patients. When the number of patients older than 65 years of age increased to 80%, the overall 2-year survival for hemodialysis decreased to 60%. The average life expectancy for older hemodialysis patients is 2.6 years [13]. As experience increases, the strategic bound- aries between bridge to transplantation, bridge to recovery, or lifetime use no longer exist. The LVAD sustains life, whereas the patient’s re- sponse determines the clinical course. For in- stance, non–transplant-eligible patients may be salvaged with a temporary device and then switched to lifetime therapy should the heart not recover. If a transplant candidate’s heart improves during LVAD unloading, there is the option for device removal instead of transplantation. In the future LVADs may also provide the platform for myocardial regeneration by neoangiogenesis, gene therapy, or stem cell therapy [14]. In REMATCH, late deaths occurred not through heart failure but from LVAD mechanical failure (35%), infective complications (41%), or stroke (10%). Advances in blood pump bioengi- neering have already dramatically reduced these risks [15]. Important developments include the fact that high-speed impellers do not damage red or white blood cells and that attenuated pulse pressure is well tolerated in the long term by the human circulation [16]. External components can be made exchangeable to combat wear and tear and the product is more user friendly for surgeon and patient (Fig. 3) [17]. In July 2006 the New England Journal of Medicine reported 6-year survival in the first patient to receive a miniaturized axial flow pump for lifetime use [18]. The Jarvik 2000 LVAD (Jar- vik Heart, New York) was tested in laboratory programs in Houston and Oxford (Fig. 4a, b). The 61-year-old English patient had idiopathic di- lated cardiomyopathy with longstanding biven- tricular failure. He was breathless at rest with pitting edema to the thighs, ulcerated legs, and as- cites. Left ventricular ejection fraction was less than 10%. He was rejected for cardiac transplan- tation because of renal impairment and subse- quently declined the procedure. Almost 7 years later he is NYHA Class II with an active life in the community. Pump output is around 5.0 L/min against a mean blood pressure of between 70 to 80 mm Hg, usually with a pulse pressure of 10 to 15 mm Hg. Power is delivered by way of a skull-mounted titanium pedestal, which has remained infection free (see Fig. 3). The external cables, controller, and batteries have all required exchange for wear and tear. Less than 5% of the follow-up period has been spent in hospital and total cost has been around $200,000. After extensive laboratory testing suggested that continuous pump flow and attenuated pulse pressure were safe in the long term, the Oxford Group proceeded to a pilot study of lifetime support in nine Stage D patients who had end- stage dilated cardiomyopathy. All had been turned down for cardiac transplantation because of renal dysfunction with or without elevated pulmonary vascular resistance. Two died in hospital from right heart and multiorgan failure. Three are alive and well without an adverse event between 13 months and 6.8 years postoperatively. Three others have died at 12 months, 26 months, 35 months post- operatively, all from noncardiac causes. A fourth patient had enjoyed 3.5 years of event-free in- dependent life more than 200 miles away from the implanting center. He died of acute left ventricular failure after failing to take a replacement battery on an excursion. At autopsy in all these patients the pump and vascular graft were free from thrombosis and there were no signs of thromboembolism. The skull pedestal remained free from infection in each case. The explanted LVADs continued to function normally on the bench. So far the Jarvik 2000 has proven to be 100% mechanically reliable in 150 implants and has a lower complication rate than pulsatile pumps [19]. Careful medical management plays an impor- tant part in the symbiotic relationship between a rotary blood pump and an improving native heart. These LVADs are particularly sensitive to differential pressure across the rotor (afterload) [15]. An increase in peripheral vascular resistance can dramatically reduce pump flow leading to renewed symptoms. The patients benefit from continuous afterload reduction by angiotensin- converting enzyme inhibition, a beta-blocker, or both. The native heart responds to exercise by in- creasing cardiac output through the apical LVAD and the aortic valve. Longstanding Jarvik 2000 patients are maintained with a mean systemic blood pressure of 60 to 70 mm Hg and little more than 10 to 20 mm Hg pulse pressure [18] . They can exercise without changing the pump speed from 10,000 rpm. 371LIFETIME CIRCULATORY SUPPORT Index Note: Page numbers of article titles are in boldface type. A Aldosterone antagonists, in advanced heart failure, 323 American Heart Association (AHA)/American College of Cardiology (ACC), management of heart failure and, 325 Angiotensin receptor blockers, in advanced heat failure, 324 Aortic regurgitation, chronic volume overload in, 293 conditions causing, 292–294 decision for aortic valve surgery in, 293 impaired systolic function in, 293 natural history of, 292–293 pressure overload in, 292 severe chronic, 293 Aortic stenosis, aortic valve replacement in, 294–295 causes of, 294 mild, natural history of, 294 transition from asymptomatic to symptomatic stage of, 294 Aortic valve, percutaneous replacement of, 296–297 Aortic valve disease, surgical treatment of, 292–295 tricuspid valve disease in, 295 Aortic valve replacement, in aortic stenosis, 294–295 return of congestive heart failure following, 295 Aortic valve surgery, decision for, in aortic regurgitation, 293 in advanced heart failure, 329–330 B Biomedical devices, for heart failure, 295–296 C Cardiac assist devices, mechanical, 299, 300 Cardiac defibrillator, automatic implantable, in advanced heart failure, 326–327 inflatable, 269 Cardiac resynchronization therapy. See Resynchronization therapy. Cardiac support systems, fully implantable pulsatile, 299, 300 Cardiac transplantation. See Transplantation, cardiac. Cardiomyopathy, dilated. See Dilated cardiomyopathy. hypertrophic. See Hypertrophic cardiomyopathy. Circulatory support, lifetime, must not be restricted to transplant centers, 369–375 mechanical, in advanced heart failure, 331, 332 Coagulopathies, destination mechanical circulatory support devices and, 331, 353 Congestive heart failure. See Heart failure, congestive. Coronary artery bypass surgery, in advanced heart failure, 328 Coronary interventions, percutaneous, in advanced heart failure, 327–328 D Defibrillator, cardiac, automatic implantable, in advanced heart failure, 326–327 inflatable, 269 Destination mechanical circulatory support devices, adverse events associated with, incidence of, 352 areas of research for, 358 biocompatibility of, 362–363 clinical implementation delay and, 357 clinically evaluated, characteristics of, 354–355 1551-7136/07/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved. doi:10.1016/S1551-7136(07)00093-1 heartfailure.theclinics.com Heart Failure Clin 3 (2007) 377–380 . 357 clinically evaluated, characteristics of, 354–355 155 1-7 136/07/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved. doi :10. 1016/S155 1-7 136(07)0009 3-1 heartfailure.theclinics.com Heart. lifetime therapy should the heart not recover. If a transplant candidate’s heart improves during LVAD unloading, there is the option for device removal instead of transplantation. In the future. [17]. In July 2006 the New England Journal of Medicine reported 6-year survival in the first patient to receive a miniaturized axial flow pump for lifetime use [18]. The Jarvik 2000 LVAD (Jar- vik Heart,