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Karimov JH, Zhen-Yu Tong M, Byram N, Sunagawa G, Dessoffy R, Moazami N, Starling RC, Fukamachi K. The axial continuous-flow blood pump: Bench evaluation of changes in flow associated with changes of inflow cannula angle. J Heart Lung Transplant 2016; 36:106-112. [PMID: 28029574 DOI: 10.1016/j.healun.2016.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 08/19/2016] [Accepted: 09/07/2016] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND Changes in the geometry of the HeartMate II (HMII) inflow cannula have been implicated in device thrombosis post-implant. The purpose of this in vitro study was to evaluate what effects changing the angle of the cannula in relation to the pump may have on pump flow and arterial pressure, under simulated inflow conditions. METHODS The HMII with an inflow cannula was mounted on a mock loop consisting of a pulsatile pneumatic ventricle to simulate the native ventricle. The angles of the HMII in relation to the inflow cannula were adjusted by separate fixed gooseneck holders. A custom-made miniature steerable camera was introduced into a flexible portion of the HMII inflow cannula. Endoscopic views of various types of inflow cannula constriction (bending, squeezing, stretching and twisting) were recorded, and pump flow and systemic arterial pressure (AoP) were assessed during each simulation. RESULTS Baseline mean pump flow (3.5 liters/min) and mean AoP (91.5 mm Hg) were unchanged by bending maximally in 2 different directions, twisting up to 30°, stretching (compression or extension), or occluding the inflow graft <90%. However, mean pump flow and mean AoP decreased substantially when the inflow graft became occluded by ≥90% by sliding or squeezing. CONCLUSIONS "Less-than-critical" obstruction (what we define here as <90%) of the HMII inflow cannula did not reveal substantial changes in pump flow or AoP. Data suggest that a major alteration to inflow cannula geometry is required to achieve clinically relevant hemodynamic changes. These data confirm that minor changes in angulation of the inflow cannula have no impact on flow through the device.
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Sunagawa G, Koprivanac M, Karimov JH, Moazami N, Fukamachi K. Is a pulse absolutely necessary during cardiopulmonary bypass? Expert Rev Med Devices 2016; 14:27-35. [DOI: 10.1080/17434440.2017.1265445] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Karimov JH, Horvath DJ, Okano S, Goodin M, Sunagawa G, Byram N, Moazami N, Golding LAR, Fukamachi K. Thrombotic Depositions on Right Impeller of Double-Ended Centrifugal Total Artificial Heart In Vivo. Artif Organs 2016; 41:476-481. [PMID: 27878837 DOI: 10.1111/aor.12778] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 03/22/2016] [Accepted: 05/11/2016] [Indexed: 12/26/2022]
Abstract
The development of total artificial heart devices is a complex undertaking that includes chronic biocompatibility assessment of the device. It is considered particularly important to assess whether device design and features can be compatible long term in a biological environment. As part of the development program for the Cleveland Clinic continuous-flow total artificial heart (CFTAH), we evaluated the device for signs of thrombosis and biological material deposition in four animals that had achieved the intended 14-, 30-, or 90-day durations in each respective experiment. Explanted CFTAHs were analyzed for possible clot buildup at "susceptible" areas inside the pump, particularly the right pump impeller. Depositions of various consistency and shapes were observed. We here report our findings, along with macroscopic and microscopic analysis post explant, and provide computational fluid dynamics data with its potential implications for thrombus formation.
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Tsuda H, Alexander D, Alexander W, Abd Elgied M, Elgazzar A, Xu J, Numano T, Suzui M, Futakuchi M, Fukamachi K, Hirose A, Kanno J. Development of a mechanism based short-term assay protocol to test carcinogenicity of multiple wall carbon nanotubes (MWNCTs) in the rat. Toxicol Lett 2016. [DOI: 10.1016/j.toxlet.2016.07.096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Karimov JH, Horvath DJ, Byram N, Sunagawa G, Grady P, Sinkewich M, Moazami N, Sale S, Golding LAR, Fukamachi K. Deairing Techniques for Double-Ended Centrifugal Total Artificial Heart Implantation. Artif Organs 2016; 41:568-572. [PMID: 27654489 DOI: 10.1111/aor.12775] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/02/2016] [Accepted: 05/05/2016] [Indexed: 11/28/2022]
Abstract
The unique device architecture of the Cleveland Clinic continuous-flow total artificial heart (CFTAH) requires dedicated and specific air-removal techniques during device implantation in vivo. These procedures comprise special surgical techniques and intraoperative manipulations, as well as engineering design changes and optimizations to the device itself. The current study evaluated the optimal air-removal techniques during the Cleveland Clinic double-ended centrifugal CFTAH in vivo implants (n = 17). Techniques and pump design iterations consisted of developing a priming method for the device and the use of built-in deairing ports in the early cases (n = 5). In the remaining cases (n = 12), deairing ports were not used. Dedicated air-removal ports were not considered an essential design requirement, and such ports may represent an additional risk for pump thrombosis. Careful passive deairing was found to be an effective measure with a centrifugal pump of this design. In this report, the techniques and design changes that were made during this CFTAH development program to enable effective residual air removal and prevention of air embolism during in vivo device implantation are explained.
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Fukamachi K, Horvath DJ, Byram N, Sunagawa G, Karimov JH, Moazami N. Advanced ventricular assist device with pulse augmentation and automatic regurgitant-flow shut-off. J Heart Lung Transplant 2016; 35:1519-1521. [PMID: 27574737 DOI: 10.1016/j.healun.2016.07.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/11/2016] [Accepted: 07/14/2016] [Indexed: 10/21/2022] Open
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Karimov JH, Sunagawa G, Horvath D, Fukamachi K, Starling RC, Moazami N. Limitations to Chronic Right Ventricular Assist Device Support. Ann Thorac Surg 2016; 102:651-8. [DOI: 10.1016/j.athoracsur.2016.02.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 01/20/2016] [Accepted: 02/01/2016] [Indexed: 12/16/2022]
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Fukamachi K, Horvath D, Byram N, Sunagawa G, Karimov J, Kuban B, Dessoffy R, Moazami N. Advanced Ventricular Assist Device with Pulse Augmentation and Automatic Regurgitant Flow Shutoff. J Heart Lung Transplant 2016. [DOI: 10.1016/j.healun.2016.01.943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Steffen RJ, Miletic KG, Schraufnagel DP, Vargo PR, Fukamachi K, Stewart RD, Moazami N. Mechanical circulatory support in pediatrics. Expert Rev Med Devices 2016; 13:507-14. [DOI: 10.1586/17434440.2016.1162710] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Sunagawa G, Byram N, Karimov JH, Horvath DJ, Moazami N, Starling RC, Fukamachi K. The Contribution to Hemodynamics Even at Very Low Pump Speeds in the HVAD. Ann Thorac Surg 2016; 101:2260-4. [PMID: 26912300 DOI: 10.1016/j.athoracsur.2015.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/25/2015] [Accepted: 12/07/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND We recently reported using bench testing that the Thoratec HeartMate II at 6,000 rpm contributed to hemodynamics when the heart had not recovered well, making weaning assessment questionable. In this bench study, we characterized hemodynamics and pump flow of the HeartWare HVAD at 1,800 rpm, the lowest speed commonly used to assess clinical recovery. METHODS The HVAD was operated in a mock loop at 1,800, 2,400, and 3,000 rpm. We acquired pressure-flow curves in each steady state. In pulsatile mode with the pneumatic ventricle (heart simulator) activated, pump flow, total flow, and aortic pressure (AoP) data were obtained under conditions simulating normal heart function or heart failure. RESULTS A large regurgitant flow during diastole was confirmed during normal heart function at 1,800 rpm support; however, the net flow was zero, and there was no difference in mean AoP between 1,800 rpm support and no HVAD support. In contrast, in the heart failure condition, HVAD flow at 1,800 rpm significantly contributed to mean AoP and total flow, because there was less regurgitant flow. CONCLUSIONS Similar to the results for the HeartMate II at 6,000 rpm, we found that the net pump flow generated by the HeartWare HVAD at 1,800 rpm depends on the degree of residual left ventricular (LV) function. In the setting of improved LV function, at 1,800 rpm we noted a large regurgitant flow. Although this "marker" can serve as a useful indicator for recovery, assessing recovery at this speed is flawed unless measures are taken to prevent regurgitant flow.
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Sunagawa G, Horvath DJ, Karimov JH, Moazami N, Fukamachi K. Future Prospects for the Total Artificial Heart. Expert Rev Med Devices 2016; 13:191-201. [PMID: 26732059 DOI: 10.1586/17434440.2016.1136212] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A total artificial heart (TAH) is the sole remaining option for patients with biventricular failure who cannot be rescued by left ventricular assist devices (LVADs) alone. However, the pulsatile TAH in clinical use today has limitations: large pump size, unknown durability, required complex anticoagulation regimen, and association with significant postsurgical complications. That pump is noisy; its large pneumatic driving lines traverse the body, with bulky external components for its drivers. Continuous-flow pumps, which caused a paradigm shift in the LVAD field, have already contributed to the rapidly evolving development of TAHs. Novel continuous-flow TAHs are only in preclinical testing or developmental stages. We here review the current state of TAHs, with recommended requirements for the TAH of the future.
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Karimov JH, Moazami N, Sunagawa G, Kobayashi M, Byram N, Sale S, Such KA, Horvath DJ, Golding LA, Fukamachi K. Median Sternotomy or Right Thoracotomy Techniques for Total Artificial Heart Implantation in Calves. Artif Organs 2015; 40:1022-1027. [DOI: 10.1111/aor.12660] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Sunagawa G, Byram N, Karimov JH, Horvath DJ, Moazami N, Starling RC, Fukamachi K. In vitro hemodynamic characterization of HeartMate II at 6000 rpm: Implications for weaning and recovery. J Thorac Cardiovasc Surg 2015. [DOI: 10.1016/j.jtcvs.2015.04.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Karimov JH, Moazami N, Kobayashi M, Sale S, Such K, Byram N, Sunagawa G, Horvath D, Gao S, Kuban B, Golding LAR, Fukamachi K. First report of 90-day support of 2 calves with a continuous-flow total artificial heart. J Thorac Cardiovasc Surg 2015; 150:687-93.e1. [PMID: 26173607 DOI: 10.1016/j.jtcvs.2015.06.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 05/13/2015] [Accepted: 06/04/2015] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The Cleveland Clinic continuous-flow total artificial heart (CFTAH) is a compact, single-piece, valveless, pulsatile pump providing self-regulated hemodynamic output to left/right circulation. We evaluated chronic in vivo pump performance, physiologic and hemodynamic parameters, and biocompatibility of the CFTAH in a well-established calf model. METHODS CFTAH pumps have been implanted in 17 calves total. Hemodynamic parameters, pump performance, and device-related adverse events were evaluated during studies and at necropsy. RESULTS In vivo experiments demonstrated good hemodynamic performance (pump flow, 7.3 ± 0.7 L/min; left atrial pressure, 16 ± 3 mm Hg; right atrial pressure, 17 ± 3 mm Hg; right atrial pressure-left atrial pressure difference, 1 ± 2 mm Hg; mean arterial pressure, 103 ± 7 mm Hg; arterial pulse pressure, 30 ± 11 mm Hg; and pulmonary arterial pressure, 34 ± 5 mm Hg). The CFTAH has operated within design specifications and never failed. With ever-improving pump design, the implants have shown no chronic hemolysis. Three animals with recent CFTAH implantation recovered well, with no postoperative anticoagulation, during planned in vivo durations of 30, 90, and 90 days (last 2 were intended to be 90-day studies). All these longest-surviving cases showed good biocompatibility, with no thromboembolism in organs. CONCLUSIONS The current CFTAH has demonstrated reliable self-regulation of hemodynamic output and acceptable biocompatibility without anticoagulation throughout 90 days of chronic implantation in calves. Meeting these milestones is in accord with our strategy to achieve transfer of this unique technology to human surgical practice, thus filling the urgent need for cardiac replacement devices as destination therapy.
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Karimov JH, Horvath D, Sunagawa G, Byram N, Moazami N, Golding LAR, Fukamachi K. Post-explant visualization of thrombi in outflow grafts and their junction to a continuous-flow total artificial heart using a high-definition miniaturized camera. J Artif Organs 2015; 18:354-7. [PMID: 25939428 DOI: 10.1007/s10047-015-0839-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 04/18/2015] [Indexed: 11/24/2022]
Abstract
Post-explant evaluation of the continuous-flow total artificial heart in preclinical studies can be extremely challenging because of the device's unique architecture. Determining the exact location of tissue regeneration, neointima formation, and thrombus is particularly important. In this report, we describe our first successful experience with visualizing the Cleveland Clinic continuous-flow total artificial heart using a custom-made high-definition miniature camera.
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Moazami N, Dembitsky WP, Adamson R, Steffen RJ, Soltesz EG, Starling RC, Fukamachi K. Does pulsatility matter in the era of continuous-flow blood pumps? J Heart Lung Transplant 2014; 34:999-1004. [PMID: 25447568 DOI: 10.1016/j.healun.2014.09.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 09/05/2014] [Accepted: 09/19/2014] [Indexed: 10/24/2022] Open
Abstract
Despite significant improved survival with continuous flow left ventricular assist devices (LVADs), complications related to aortic valve insufficiency, gastrointestinal bleeding, stroke, pump thrombosis, and hemolysis have dampened the long term success of these pumps. Evolution has favored a pulsatile heart pump to be able to deliver the maximum flow at different levels of systemic vascular resistance, confer kinetic energy to the flow of blood past areas of stenosis and generate low shear stress on blood elements. In this perspective, we suggest that lack of pulsatility may be one factor that has limited the success of continuous flow LVADs and suggest that research needs to focus on methods to generate pulsatility either by the native heart or by various speed modulation algorithms.
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Steffen RJ, Halbreiner MS, Zhang L, Fukamachi K, Soltesz EG, Starling RC, Moazami N. Mechanical circulatory support for the right ventricle in the setting of a left ventricular assist device. Expert Rev Med Devices 2014; 11:587-93. [DOI: 10.1586/17434440.2014.940316] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Karimov JH, Dessoffy R, Kobayashi M, Dudzinski DT, Klatte RS, Kattar J, Moazami N, Fukamachi K. Motion-activated prevention of clogging and maintenance of patency of indwelling chest tubes. Interact Cardiovasc Thorac Surg 2014; 19:1-5. [DOI: 10.1093/icvts/ivu089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Karimov JH, Massiello AL, Fukamachi K. Overview of current sutureless and transcatheter mitral valve replacement technology. Expert Rev Med Devices 2014; 10:73-83. [DOI: 10.1586/erd.12.66] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Fumoto H, Shiose A, Flick CR, Noble LD, Dudzinski DT, Casas F, Takaseya T, Arakawa Y, Fukamachi K, Smith WA, Duncan BW. Short-Term In Vivo Performance of the Cleveland Clinic PediPump Left Ventricular Assist Device. Artif Organs 2013; 38:374-82. [DOI: 10.1111/aor.12179] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Fukamachi K. Current Status of Artificial Heart (Assist/Replacement) Development in the United States. Artif Organs 2013; 37:675-6. [DOI: 10.1111/aor.12097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kobayashi M, Massiello A, Karimov JH, Van Wagoner DR, Fukamachi K. Cardiac autonomic nerve stimulation in the treatment of heart failure. Ann Thorac Surg 2013; 96:339-45. [PMID: 23747176 DOI: 10.1016/j.athoracsur.2012.12.060] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 12/14/2012] [Accepted: 12/21/2012] [Indexed: 01/01/2023]
Abstract
Research on the therapeutic modulation of cardiac autonomic tone by electrical stimulation has yielded encouraging early clinical results. Vagus nerve stimulation has reduced the rates of morbidity and sudden death from heart failure, but therapeutic vagus nerve stimulation is limited by side effects of hypotension and bradycardia. Sympathetic nerve stimulation that has been implemented in the experiment may exacerbate the sympathetic-dominated autonomic imbalance. In contrast, concurrent stimulation of both sympathetic and parasympathetic cardiac nerves increases myocardial contractility without increasing heart rate. This review assesses the current state of electrical stimulation of the cardiac autonomic nervous system to treat heart failure.
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Moazami N, Fukamachi K, Kobayashi M, Smedira NG, Hoercher KJ, Massiello A, Lee S, Horvath DJ, Starling RC. Axial and centrifugal continuous-flow rotary pumps: a translation from pump mechanics to clinical practice. J Heart Lung Transplant 2013; 32:1-11. [PMID: 23260699 DOI: 10.1016/j.healun.2012.10.001] [Citation(s) in RCA: 214] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 09/19/2012] [Accepted: 10/17/2012] [Indexed: 11/19/2022] Open
Abstract
The recent success of continuous-flow circulatory support devices has led to the growing acceptance of these devices as a viable therapeutic option for end-stage heart failure patients who are not responsive to current pharmacologic and electrophysiologic therapies. This article defines and clarifies the major classification of these pumps as axial or centrifugal continuous-flow devices by discussing the difference in their inherent mechanics and describing how these features translate clinically to pump selection and patient management issues. Axial vs centrifugal pump and bearing design, theory of operation, hydrodynamic performance, and current vs flow relationships are discussed. A review of axial vs centrifugal physiology, pre-load and after-load sensitivity, flow pulsatility, and issues related to automatic physiologic control and suction prevention algorithms is offered. Reliability and biocompatibility of the two types of pumps are reviewed from the perspectives of mechanical wear, implant life, hemolysis, and pump deposition. Finally, a glimpse into the future of continuous-flow technologies is presented.
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Moazami N, Hoercher KJ, Fukamachi K, Kobayashi M, Smedira NG, Massiello A, Horvath DJ. Mechanical circulatory support for heart failure: past, present and a look at the future. Expert Rev Med Devices 2013; 10:55-71. [PMID: 23278224 DOI: 10.1586/erd.12.69] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Heart transplantation remains the gold standard for long-term cardiac replacement, but a shortage of donor organs will always limit this option. For both transplant-eligible and noneligible patients, advances in mechanical circulatory support have revolutionized the options for the management of end-stage heart failure, and this technology continues to bring us closer to a true alternative to heart transplantation. This review provides a perspective on the past, present and future of mechanical circulatory support and addresses the changes in technology, patient selection and management strategies needed to have this therapy fully embraced by the heart failure community, and perhaps replace heart transplantation either as the therapy of choice or as a strategy by which to delay transplantation in younger patients.
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