Recommendations for the Use of Mechanical Circulatory Support: Device Strategies and Patient Selection
2012; Lippincott Williams & Wilkins; Volume: 126; Issue: 22 Linguagem: Inglês
10.1161/cir.0b013e3182769a54
ISSN1524-4539
AutoresJennifer L. Peura, Monica Colvin, Gary S. Francis, Kathleen L. Grady, Timothy M. Hoffman, Mariell Jessup, Ranjit John, Michael S. Kiernan, Judith E. Mitchell, John B. OʼConnell, Francis D. Pagani, Michael Petty, Pasala Ravichandran, Joseph G. Rogers, Marc J. Semigran, John M. Toole,
Tópico(s)Cardiac Arrest and Resuscitation
ResumoHomeCirculationVol. 126, No. 22Recommendations for the Use of Mechanical Circulatory Support: Device Strategies and Patient Selection Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBRecommendations for the Use of Mechanical Circulatory Support: Device Strategies and Patient SelectionA Scientific Statement From the American Heart Association Jennifer L. Peura, MD, Chair, Monica Colvin-Adams, MD, MS, FAHA, Co-Chair, Gary S. Francis, MD, FAHA, Kathleen L. Grady, PhD, APN, FAHA, Timothy M. Hoffman, MD, FAHA, Mariell Jessup, MD, FAHA, Ranjit John, MD, Michael S. Kiernan, MD, Judith E. Mitchell, MD, FAHA, John B. O'Connell, MD, Francis D. Pagani, MD, PhD, FAHA, Michael Petty, PhD, RN, Pasala Ravichandran, MD, Joseph G. Rogers, MD, Marc J. Semigran, MD, FAHA and J. Matthew Toole, MD, FAHAon behalf of the American Heart Association Heart Failure and Transplantation Committee of the Council on Clinical CardiologyCouncil on Cardiopulmonary, Critical Care, Perioperative and ResuscitationCouncil on Cardiovascular Disease in the YoungCouncil on Cardiovascular NursingCouncil on Cardiovascular Radiology and Intervention, and Council on Cardiovascular Surgery and Anesthesia Jennifer L. PeuraJennifer L. Peura , Monica Colvin-AdamsMonica Colvin-Adams , Gary S. FrancisGary S. Francis , Kathleen L. GradyKathleen L. Grady , Timothy M. HoffmanTimothy M. Hoffman , Mariell JessupMariell Jessup , Ranjit JohnRanjit John , Michael S. KiernanMichael S. Kiernan , Judith E. MitchellJudith E. Mitchell , John B. O'ConnellJohn B. O'Connell , Francis D. PaganiFrancis D. Pagani , Michael PettyMichael Petty , Pasala RavichandranPasala Ravichandran , Joseph G. RogersJoseph G. Rogers , Marc J. SemigranMarc J. Semigran and J. Matthew TooleJ. Matthew Toole and on behalf of the American Heart Association Heart Failure and Transplantation Committee of the Council on Clinical Cardiologyand Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitationand Council on Cardiovascular Disease in the Youngand Council on Cardiovascular Nursingand Council on Cardiovascular Radiology and Intervention, and Council on Cardiovascular Surgery and Anesthesia Originally published29 Oct 2012https://doi.org/10.1161/CIR.0b013e3182769a54Circulation. 2012;126:2648–2667Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: January 1, 2012: Previous Version 1 IntroductionThe era of mechanical circulatory support (MCS) began in 1953 with the development of cardiopulmonary bypass to facilitate open heart surgery.1 In 1964, the National Heart Institute (now the National Heart, Lung, and Blood Institute) funded the Artificial Heart Program and became actively involved in MCS development. This led to requests for Proposals issued in 1977 and 1980, which laid the foundation for the development of implantable MCS for long-term use, including devices capable of hospital discharge, in the 1990s. Although heart transplantation is now commonplace at many hospitals, the inadequate supply of donor hearts and patient contraindications to transplantation continue to severely restrict its application. As the demand for long-term replacement of diseased hearts increases, there is a clear need for innovative, safe, and durable MCS to treat the growing population of patients with advanced heart failure (HF). Many exciting changes in the field of MCS have occurred in the past few years, including the development of smaller portable pumps and the concept of destination therapy (DT), or permanent pump placement as an alternative to heart transplantation. Currently, there are no published guidelines for the use of MCS. Thus, it is our intent that this statement will provide the contemporary cardiologist and other HF providers with an understanding of general considerations when determining the appropriateness of MCS.Definition of Advanced HFThere is little hope that complete consensus will ever be reached on the definition of advanced HF, but most physicians caring for such patients on a regular basis readily identify the characteristics of these patients. Advanced HF patients are those with clinically significant circulatory compromise who require special care, including consideration for heart transplantation, continuous intravenous inotropic therapy, MCS, or hospice.2,3 Typically, such patients have symptoms at rest or with minimal exertion and cannot perform many activities of daily living.3 Commonly used objective measures of functional limitations include a peak Vȯ2 ≤14 mL · kg−1 · min−1 (or <50% of expected) and a 6-minute walk distance <300 m.3 Many have cardiac cachexia, are failing or intolerant of conventional HF therapy, and require repeated hospitalization for more intensive management.4 Advanced HF patients usually have a life expectancy of 50% with medical therapy (Class II; Level of Evidence B)HFSA comprehensive HF practice guidelines8 Patients awaiting heart transplantation who have become refractory to all means of medical circulatory support should be considered for an MCS device as a BTT (Level of Evidence B) Permanent mechanical assistance with an implantable LVAD may be considered in highly selected patients with severe HF refractory to conventional therapy who are not candidates for heart transplantation, particularly those who cannot be weaned from intravenous inotropic support at an experienced HF center (Level of Evidence B) Patients with refractory HF and hemodynamic instability and/or compromised end-organ function with relative contraindications to cardiac transplantation or permanent MCS expected to improve with time or restoration of an improved hemodynamic profile should be considered for urgent MCS as a bridge to decision; these patients should be referred to a center with expertise in the management of patients with advanced HF (Level of Evidence C)Canadian HF guidelines9 MCS may be offered to selected individuals with end-stage heart failure who are inotrope dependent and do not meet the traditional criteria for cardiac transplantation (Class IIb; Level of Evidence B)ESC guidelines 2008/201010,11 Current indications for LVADs and artificial hearts include bridging to transplantation and managing patients with acute, severe myocarditis (Class IIa; Level of Evidence C) Although experience is limited, these devices may be considered for long-term use when no definitive procedure is planned (Class IIb; Level of Evidence C) LVAD may be considered as destination treatment to reduce mortality (Class IIa; Level of Evidence B)MCS indicates mechanical circulatory support; AHA, American Heart Association; ACCF, American College of Cardiology Foundation; HF, heart failure; LVAD, left ventricular assist device; HFSA, Heart Failure Society of America; BTT, bridge to transplantation; and ESC, European Society of Cardiology.Management Strategies for the MCS PatientSelection Criteria and Decision ProcessThe approach to MCS is determined by the trajectory of HF progression and overall clinical status. Because there are temporary and durable device options, extracorporeal, implantable, or percutaneous strategies for MCS are as broad and variable as the patients requiring this therapy. MCS may be used as a BTT for transplantation-eligible patients and as DT for those who are transplantation ineligible. These designations are fluid, however, because the patient's candidacy for either therapy may change over time (Figure 1). For example, a DT patient may become transplant eligible after significant improvement in comorbidities that previously precluded consideration for transplantation. Alternatively, a transplantation-eligible patient may become ineligible after MCS because of perioperative complications, progression of comorbidities, or personal preference. In circumstances when a patient presents in cardiogenic shock, it may not be possible to fully determine candidacy for transplantation. MCS may be used to determine neurological recovery and to stabilize potentially reversible comorbidities. In these situations, MCS is used as a bridge to decision or bridge to recovery.Download figureDownload PowerPointFigure 1. Device selection flow chart. OHTx indicates orthotopic heart transplantation; IABP, intra-aortic balloon pump; ECMO, extracorporeal membrane oxygenation; pVAD, Paracorporeal Ventricular Assist Device; BTT, bridge to transplantation; DT, destination therapy; and BTD, bridge to decision.It is important to underscore 2 important principles that have evolved over the past decade. First, some patients are too profoundly ill with multisystem organ failure to benefit from the very best of MCS and aggressive inotropic therapy. Second, complex decisions about candidacy for transplantation or MCS are best made by an experienced, multidisciplinary team. Although it may become appropriate for smaller programs to implant elective DT MCS in highly selected patients, more acutely ill patients should be referred to quaternary care hospitals that are accustomed to the management of such patients. In the following sections, strategies for MCS are discussed.Indications for MCSBridge to RecoveryThe first application of extracorporeal MCS focused on temporary maintenance of the circulation after an acute event until the occurrence of cardiac recovery. The earliest clinical example was the use of MCS in patients with postcardiotomy shock in whom failure to wean from cardiopulmonary bypass was considered certain death unless the patient could be rescued with temporary MCS. This pattern established the concept and indication of bridge to recovery in which temporary MCS sustained the circulation until cardiac recovery. A robust experience with temporary MCS for failure to wean from bypass led to the application of MCS in nonpostcardiotomy settings such as cardiogenic shock caused by myocardial infarction, fulminant or acute myocarditis, or acute cardiac allograft dysfunction after heart transplantation.Compared with early options for MCS, modern devices (Table 2) provide longer duration and more versatile support. These devices, called nondurable MCS, may be used as a first step when rapid support is necessary in patients with cardiogenic shock who are at too high a risk for implantation of a durable device or as an alternative to durable implantable devices if recovery is possible. For these patients, a bridge with a nondurable device provides essential stabilization and permits clarification and potential reversal of the other medical issues that may interfere with a satisfactory outcome after transplantation or long-term device placement. The following nondurable devices are used for bridge to recovery and for temporary support until more definitive therapies can be used in patients in whom myocardial recovery does not occur.Table 2. Devices Available for Short-Term MCSDeviceManufacturerMechanismPositionDurationIABPMultipleCounterpulsationNADaysECMOMultipleCPBNADays–weeksBVS5000, AB5000ABIOMEDPulsatileR, L, or BilateralWeeksThoratec pVADThoratecPulsatileR, L, or BilateralWeeksCentriMagLevitronixCentrifugalR, L, or BilateralWeeksTandemHeartCardiacAssistCentrifugalpMCSDaysImpellaABIOMEDAxial flowpMCSDaysMCS indicates mechanical circulatory support; IABP, intra-aortic balloon pump; NA, not applicable; ECMO, extracorporeal membrane oxygenation; CPB, cardiopulmonary bypass; R, right; L, left; pVAD, percutaneous ventricular assist device; and pMCS, percutaneous mechanical circulatory support.Intra-Aortic Balloon PumpThe intra-aortic balloon pump (IABP) is broadly used and is commonly the first step in the treatment of cardiogenic shock. The IABP provides hemodynamic support for cardiogenic shock by diastolic augmentation of aortic pressure and left ventricular afterload reduction. Coronary perfusion is also increased, which may be important in the setting of increased ventricular diastolic pressure, even in the absence of critical coronary artery stenosis. Although relatively easy to insert in the community setting, the use of the IABP is limited to short durations of support because of potential arterial complications and the inability to mobilize patients. It may be insufficient in the setting of marked cardiac failure.Extracorporeal Membrane OxygenationExtracorporeal membrane oxygenation (ECMO) is used to treat medically refractory cardiogenic shock when there is poor oxygenation, and ECMO can be a rapid option for emergency biventricular support. ECMO uses a nonpulsatile pump, membrane oxygenator, and inflow and outflow cannulas. Arterial and venous access can be obtained via peripheral cannulation of the femoral vessels, which can be applied rapidly at the bedside.12 Survival of patients treated with ECMO reflects the critical nature of the patients in whom it is used. In adults, 1 study reported 58% survival to hospital discharge,13 and another reported survival rates of 76% (3 days), 38% (30 days), and 24% (5 years).14 In the pediatric population, ECMO use is more prevalent,12 yet survival is still modest (43%–54%).15,16 Outcomes may be improved when ECMO is used for specific indications such as acute myocarditis, in which survival was reported to be as high as 83% in pediatric17 and 75% in adult18 patients. Major limitations for the use of ECMO remain its lack of durability (weeks of support), limited availability, necessary perfusion support, and complications related to vascular access.Extracorporeal MCSEarly pulsatile, extracorporeal devices provided salvage support for patients in cardiogenic shock who otherwise faced an extremely high risk of mortality.19 These extracorporeal devices were implanted via a traditional sternotomy with an external pumping chamber and drive console (Figure 2). The first of these devices was the Abiomed BVS5000 (ABIOMED, Inc, Danvers, MA), a nondurable, extracorporeal, pulsatile, pneumatic device with a large external controller. It was approved by the US Food and Drug Administration (FDA) after a prospective, nonrandomized, multicenter trial of 55 patients with postcardiotomy shock. Fifty-five percent of patients were weaned from support, and 29% of patients survived to discharge.20 The following pulsatile pumps have been approved for rescue therapy: Abiomed AB5000 (ABIOMED, Inc) and the Thoratec Paracorporeal Ventricular Assist Device II (Thoratec Corp, Pleasanton, CA). Survival with the Paracorporeal Ventricular Assist Device was 48% in a nonrandomized trial of 29 patients with postcardiotomy shock.21–23 Finally, the CentriMag (Levitronix LLC, Waltham, MA) is a nondurable, extracorporeal, continuous, centrifugal-flow pump with a magnetically levitated rotor and external controller that is designed to support the left, right, or both ventricles.24,25 This system is capable generating flows up to 10 L/min under normal physiological conditions. The CentriMag may also be used to provide temporary right ventricular (RV) support after left VAD (LVAD) insertion and has FDA approval for use for up to 30 days for this indication. In a multicenter study, 38 patients with cardiogenic shock were supported with CentriMag, and overall 30-day survival was 47%.26 Several studies have reported support with the CentriMag system for >100 days without any instances of pump failure or thromboembolic events.27 Some centers are using the CentriMag device for ECMO support, allowing rapid initiation of biventricular support.Download figureDownload PowerPointFigure 2. Device diagrams. Reprinted with permission from Thoratec and from CardiacAssist.Percutaneous MCSThe TandemHeart (CardiacAssist, Inc, Pittsburgh, PA) is a nondurable, percutaneous, continuous-flow centrifugal pump with an external controller. It can be placed in the cardiac catheterization laboratory and generates up to 5 L/min of flow. This device uses transseptal left atrial inflow via a percutaneous femoral venous cannula and outflow via a contralateral femoral arterial cannula.28,29 Removal of the device is done at the bedside or at the time of durable MCS surgery or transplantation. The device was designed to temporarily support patients during high-risk percutaneous interventions in the cardiac catheterization laboratory and has been used successfully for postcardiotomy HF and cardiogenic shock. This device is appealing as an alternative in patients with refractory cardiogenic shock because it has the potential to avoid the morbidity and mortality associated with surgical device placement. Complications of this device include bleeding, thrombosis, leg ischemia, and dislocation of transseptal or atrial cannulas. Support with the TandemHeart is reported to improve cardiac indexes, blood pressure, and mixed venous oxygen saturation30 and to reverse the terminal hemodynamic compromise seen in patients with cardiogenic shock refractory to IABP and vasopressor support.31The Impella 2.5 (ABIOMED, Inc) is a nondurable, percutaneous, continuous-flow, axial pump with an external controller. The simple design is a significant advantage for this device, allowing straightforward percutaneous insertion and rapid initiation of circulatory support in the catheterization laboratory. This device rests across the aortic valve and pumps up to 2.5 L/min of blood from the left ventricle to the ascending aorta. The Impella 2.5 may be used to support high-risk coronary angioplasty and for patients with myocardial infarction complicated by cardiogenic shock.32 Compared with treatment with IABP, the Impella 2.5 device provided superior hemodynamic support and was both feasible and safe; however, there was no difference in 30-day mortality between the 2 groups. With a maximum flow of 2.5 L/min, the use of the Impella 2.5 may be limited in patients with a large body mass index (BMI) or in those who are in cardiogenic shock and require more flow. The Impella 5.0 is of the same design, is slightly larger, and is capable of delivering 5-L/min flow. The Impella 5.0 was approved by the FDA (April 2009) for providing temporary circulatory support; however, it requires a surgical cut-down on a peripheral artery for insertion. Complications of the Impella device include bleeding, thrombosis, and limb ischemia.33,34Withdrawal of Nondurable MCSPatients who receive nondurable MCS (either percutaneous or surgically placed) should always be evaluated for possible ventricular recovery, particularly in the setting of postcardiotomy shock, myocardial infarction, or myocarditis. Weaning can be performed by assessing clinical parameters (hemodynamics and echocardiographic left ventricular function) while MCS is temporarily reduced. Although uniform guidelines for weaning MCS do not exist, it is common practice to reduce flows by 0.5 L/min while simultaneously assessing the clinical status and hemodynamics. Ventricular recovery can be detected first by the presence of native ventricular ejection on the arterial or pulmonary artery wave forms. Subsequent confirmation of recovery of ventricular function is best performed by either transthoracic or transesophageal echocardiography. It is important to confirm the presence of adequate anticoagulation and to optimize hemodynamics with invasive monitoring before weaning MCS and explantation. Percutaneous MCS can be removed at the bedside unless a femoral cut-down is performed for placement. Surgically placed MCS devices are preferably removed in the operating room, although a variety of minimally invasive techniques are being developed to facilitate easier removal.Clinical Perspective: Bridge to RecoveryTo achieve the best short-term and long-term survival, MCS must be initiated in an appropriate and timely fashion.35 Often, the patient with cardiogenic shock may also have multisystem organ failure and demonstrate an uncertain neurological status at the time of evaluation for MCS. In this situation, implantation of durable MCS is associated with poor outcomes and is not cost-effective. Implantation of nondurable MCS as a bridge to decision allows support until the clinical situation justifies the implantation of a more permanent device.36An increasing number of centers are using nondurable MCS as a means to achieve clinical stability before transfer to a specialized advanced HF center for more definitive therapy. Quick and appropriate intervention with MCS can allow stabilization and facilitate safe patient transfer, ultimately improving patient survival in the setting of cardiogenic shock. A multidisciplinary approach and excellent communication between local hospitals and specialized MCS centers can make this an effective strategy.37 It is particularly important that the advanced HF center is involved in planning for definitive therapy as early as possible, particularly before the performance of high-risk invasive procedures involving coronary angioplasty, cardiac surgery, or ventricular tachycardia ablation.Two important questions must be considered in patients with acute cardiogenic shock who are potential candidates for permanent support: (1) Which patients will benefit from temporary MCS? (2) What modality of nondurable MCS should be used? Considering the ongoing rapid evolution of these devices with concomitant improvements in efficacy and safety, the recommendation is to use the device that is familiar to the team and can best serve the needs of the patient.Bridge to TransplantationThe development of durable, implantable MCS devices was initially conceived as permanent support of the heart as an alternative to heart transplantation. However, FDA concerns about the long-term performance and safety largely restricted the initial use of implantable MCS devices to patients eligible for heart transplantation, not for patients as DT. This bias by clinicians and the FDA to limit MCS to transplant-eligible patients set the early stage for what has become the BTT indication. It also led to the regulatory pathway by which most long-term, implantable MCS devices are evaluated today. Devices with FDA approval for BTT are listed in Table 3 and described below.Table 3. Devices Approved by the FDA for Long-Term MCSDeviceManufacturerMechanismPositionIndicationsPortableThoratec pVADThoratecPulsatileR, L, or bilateralBTT, BTRYesNovacorWorld HeartPulsatileLBTT, DTYesHeartmate XVEThoratecPulsatileLBTT, DTYesHeartmate IIThoratecAxial flowLBTT, DTYesAbiomed TAHABIOMEDPulsatileBilateralBTTYes/NoCardioWest TAHSyncardiaPulsatileBilateralBTTNoBerlin EXOR PediatricBerlinPulsatile/pneumaticR, L, or bilateralBTTNoDeBakey ChildMicroMedContinuousLBTT, BTRNoFDA indicates Food and Drug Administration; MCS, mechanical circulatory support; pVAD, percutaneous ventricular assist device, R, right; L, left; BTT, bridge to transplantation; BTR, bridge to recovery; DT, destination therapy; and TAH, total artificial heart.Extracorporeal MCSThe Thoratec Paracorporeal Ventricular Assist Device II received FDA approval for BTT in 1995. With its smaller portable external driver, patients may be discharged from the hospital to await heart transplantation.38 In a review of 84 patients in a single center, survival was reported to be 56%, with 79% of patients alive 1 year after heart transplantation.39A single option for BTT in the pediatric population is the Berlin EXCOR VAD (Berlin Heart, GmbH, The Woodlands, TX), which was recently approved by the FDA. This device is an extracorporeal, pulsatile, pneumatic pump for left or biventricular support. In a report on its use in 73 children,40 overall mortality was 23%, with younger age and need for biventricular support predicting mortality by multivariable analysis.Implantable MCSThe Thoratec HeartMate vented electric XVE (Thoratec Corp) and the Novacor LVAD system (Novacor LVAS, Baxter, Oakland, CA)41 were early implantable, pulsatile, pneumatic devices with small external controllers. These devices are largely historical and are not used today. Broad implementation of the pulsatile devices for BTT was limited by the large size of the implantable pumps and the risk of device failure (reported to be 35% at 24 months).42The next generation of implantable MCS technology brought smaller and more durable devices. The current era includes continuous-, axial-, and centrifugal-flow devices.43 The HeartMate II (Thoratec Corp) is an implantable, continuous, axial-flow device with a small external controller. This device has a single moving part and a much smaller profile than earlier HeartMate devices. The HeartMate II was approved by the FDA for BTT in April 2008. In a prospective, noncontrolled, multicenter trial including 281 patients, survival was 82% at 6 months and 73% at 12 months.44 At 6 months, there was significant improvement in the 6-minute walk test, with the majority (83%) of patients in New York Heart Association (NYHA) functional class I or II. Improvement in quality of life was also recorded in patients treated as BTT. This device showed improved durability, with pump replacement required in only 4% of patients.45The MicroMed DeBakey, a continuous, axial-flow pump, is not approved by the FDA for use in adults but is available for use in children 5 to 16 years of age. Because of its small size, the MicroMed DeBakey provides an important option for children for whom there are few alternatives for MCS.46Total Artificial HeartThe earliest successes in MCS technology occurred with the total artificial heart. The original Jarvik 7–100 was used to support patients with severe HF, but its clinical application was limited by large device size and a high rate of stroke and infection. The CardioWest total artificial heart (Syncardia Systems Inc, Tucson, AZ) is an implantable, pulsatile, pneumatic pump with an external controller. It received FDA approval as a BTT in 200447 and is a modern version of the original Jarvik 7. In a multicenter trial, survival to transplantation was 79% among 81 patients supported with this device compared with 46% in the 35-patient historical medical therapy alone control group. Posttransplantation survival was superior for patients supported with the CardioWest total artificial heart (86% at 1 year, 64% at 5 years) compared with control subjects (69% at 1 year, 34% at 5 years). A portable driver for this device that would allow discharge from the hospital on support is under investigation. Development of the total artificial heart was eclipsed by the rapid growth of VAD technology; currently, the total artificial heart is reserved for patients who have severe biventricular failure and require MCS.Clinical Perspective: BTTThe number of heart transplantations performed annually (2200 per year)48 is much less than the number of patients with advanced HF. The emergence of MCS as BTT has clearly affected patient care, with 43% of all listed heart transplant recipients receiving MCS while awaiting a donor organ (http://www.srtr.org).48Mortality among patients listed for heart transplantation is considerable, especially among the inotrope-dependent population, in
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