INTRODUCTION — In patients with advanced heart failure (HF) refractory to optimal medical and device-based therapies, long-term mechanical circulatory support (MCS) with a ventricular assist device (VAD) or artificial heart may be an option. These devices can reduce the risk of death and improve quality of life . However, long-term MCS therapy requires frequent follow-up, testing, and self-care to manage residual HF symptoms, safely operate the MCS device, and prevent or treat common complications such as stroke, infection, and gastrointestinal bleeding.
This topic will discuss the evaluation and indications for MCS, types of devices, and the outcomes and complications of durable MCS therapy.
The management of patients with a long-term MCS device is discussed separately. (See "Management of long-term mechanical circulatory support devices".)
The management of cardiogenic shock with temporary MCS is discussed elsewhere. (See "Short-term mechanical circulatory assist devices" and "Intraaortic balloon pump counterpulsation" and "Short-term left ventricular mechanical circulatory support: Use of echocardiography during initiation and management".)
GOALS OF THERAPY — The primary goal of therapy with a durable MCS device is to prolong survival and improve quality of life in patients with advanced HF. In some patients who are eligible for heart transplantation, another goal of MCS therapy is to reduce the risk of mortality and to improve or maintain organ function until heart transplantation can be performed.
TYPES OF DURABLE MCS DEVICES — There are two basic types of long-term MCS devices:
Ventricular assist devices — A durable ventricular assist device (VAD) is the general term for a surgically implanted MCS device that is intended for use outside the hospital. The purpose of a VAD is to support patients with HF by increasing perfusion and reducing the filling pressures in the heart. However, VADs only assist the pumping action of the diseased ventricle, which can fill and contract, albeit at a reduced cardiac output. In patients with advanced HF who undergo VAD placement, the device augments but does not completely replace the function of the heart.
Typically, VADs consist of an "inlet cannula" (ie, a rigid metal tube) that directs blood from the left ventricle (LV) into an electrical motor, which continuously pumps blood (also known as continuous-flow VAD [CF-VAD]) into the aorta via a flexible "outflow graft" (figure 1 and figure 2). The VAD motor receives power via a "driveline" (ie, insulated cable) that extends through a tunnel in the skin to an external controller connected to batteries. The patient and their caregiver team use the controller to receive basic information about the pump’s settings, power consumption, and battery life. The controller also generates alarms indicating low battery power or other abnormalities that require the attention of the patient or their caregiver.
The two most common VADs in use are the HeartMate III device and the HeartWare device, though the HeartWare device was removed from the market in June 2021 and is no longer available for implant .
The long-term management of patients with a VAD is presented elsewhere. (See 'Education on MCS therapy and alternatives' below.)
Artificial hearts — An artificial heart is a surgically implanted MCS device that is used to treat refractory HF not amenable to treatment with a VAD. The artificial heart treats patients with HF by increasing cardiac output and reducing filling pressures. In contrast to a VAD, an artificial heart device completely replaces the function of the native heart; both ventricles and most of the atria are excised during artificial heart implantation. Compared with VADs, artificial hearts are used infrequently.
The artificial heart consists of two rigid "ventricles" that each have two valves (figure 3). One ventricle is connected between the vena cavae and pulmonary artery to pump blood to the pulmonary circulation, while the other ventricle is connected between the pulmonary veins and the aorta to pump blood to the systemic circulation. The most commonly used artificial heart rapidly shuttles air in and out of a polymer bladder contained inside the ventricles; this action creates a systolic pumping action and a diastolic "suction" effect (figure 3). Air travels to and from the patient via large pneumatic tubes ("drivers") that are tunneled through the skin to an external unit that contains a pneumatic pump, batteries, and the controller. The controller monitors the function of the pump, displays battery power and setting information, and generates alarms indicating low battery power or other abnormalities that require the attention of the patient or their caregiver.
The long-term management of patients with an artificial heart is presented elsewhere. (See 'Education on MCS therapy and alternatives' below.)
INITIAL EVALUATION — The evaluation for durable MCS device placement involves many steps and typically includes invasive testing. Thus, before proceeding with a comprehensive evaluation for durable MCS therapy, we review the following:
Diagnosis of advanced heart failure — Durable MCS devices should only be used to treat patients who have signs and symptoms of advanced HF despite optimal medical and cardiac implantable electronic device (CIED) therapy. In brief, some of the signs of advanced HF include:
●LV ejection fraction ≤25 percent and/or pulmonary capillary wedge pressure ≥25 mmHg
●Persistent New York Heart Association class IV symptoms
●Two or more recent HF hospitalizations or any recent inotrope use
●Intolerance to low doses of HF medications or refractoriness to diuretics
●Signs of poor perfusion (eg, tachycardia, worsening kidney dysfunction, hyponatremia, syncope)
●Objectively poor exercise tolerance (eg, peak VO2 <12 mL/kg/min)
●Refractory ventricular arrhythmias
A complete discussion of the diagnosis of advanced HF is discussed elsewhere. (See "Clinical manifestations and diagnosis of advanced heart failure".)
Education on MCS therapy and alternatives — In patients who have advanced HF, the next step in management is typically to educate the patient on the options available for the treatment of advanced HF and provide an overview of durable MCS device therapy:
●Alternatives to durable MCS therapy – In addition to discussing the risks and benefits of durable MCS device placement, we provide the patient with a general description of alternative therapies for advanced HF. Depending on the characteristics of the patient, these therapies may or may not be used as a bridge to transplantation (ie, therapy designed to support the patient until transplantation). The alternatives to durable MCS device placement include:
•Continued treatment with medical therapy. (See "Management of refractory heart failure with reduced ejection fraction", section on 'General management'.)
•Heart transplantation. (See "Heart transplantation in adults: Prognosis".)
•Inotropic support. (See "Management of refractory heart failure with reduced ejection fraction", section on 'Intravenous inotropes'.)
●Overview of durable MCS device therapy – While durable MCS device therapy can prolong survival and reduce symptoms associated with HF, all patients with a durable MCS device require life-long management of HF and device complications from a specialized team, meticulous self-management, and the continuous support of a dedicated caregiver. In general, long-term management consists of:
•Frequent follow-up to assess for device-related complications and residual HF
•Lifelong maintenance of anticoagulation and antiplatelet therapies
•Self-care such as battery management as well as driveline wound maintenance
•Optimal treatment of chronic conditions (eg, chronic kidney disease, depression)
•Appropriate assessment for heart transplantation
The specific outcomes and complications of durable MCS therapy and the details of management are discussed elsewhere. (See 'Prognosis and outcomes' below and "Management of long-term mechanical circulatory support devices", section on 'Complications of VADS'.)
Goals of care — After the patient receives education, we typically discuss goals of care with the patient to ensure that the risks and benefits of durable MCS device therapy align with the patient’s expectations. Details on the approach to goals of care discussion can be found elsewhere. (See "Palliative care for patients with advanced heart failure: Decision support and management of symptoms".)
Eligibility for heart transplantation — For all patients undergoing evaluation for durable MCS device placement, we consider the option of heart transplantation and evaluate for heart transplantation if appropriate; many patients eligible for MCS device placement will also be eligible for heart transplantation, and the patient’s decision to undergo MCS device placement can be influenced by the likelihood of future transplantation. (See 'Indications' below.)
The details of the transplant evaluation can be found elsewhere. (See "Heart transplantation in adults: Indications and contraindications".)
ADDITIONAL EVALUATION — In patients who have advanced HF and whose goals of care align with durable MCS device support, the next step is to determine whether relative or absolute contraindications to device therapy are present. While the exact criteria for relative and absolute contraindications vary between centers, the common goal of the presurgical evaluation is to identify relative and absolute contraindications to therapy and determine which type of device (if any) can be used for support.
Cardiovascular assessment — The cardiac assessment is focused on identifying conditions that pose a risk to the patient during the perioperative period or during the long-term phase of care.
●Right heart dysfunction – In patients who undergo LV assist device (LVAD) placement, the right ventricle (RV) can acutely fail due to the stress of surgery or fail over time as the result of the cardiomyopathic process or as the result of other factors (eg, pulmonary hypertension). RV failure of varying severity occurs frequently and is noted as a common cause of death and morbidity in patients implanted with LVAD [3,4].
Ideally, the assessment of RV function should occur at a time when the patient’s HF management is optimized. The risk of RV failure increases in the presence of one or more of the following factors:
•Central venous filling pressure ≥15 mmHg.
•RV stroke work index (RVSWI) <0.5 mmHg x L/m2 .
•Low pulmonary artery pressure index (PAPi) <2.0 .
•Pulmonary capillary wedge pressure to central venous pressure ratio >0.63 .
•Signs of liver congestion and coagulopathy (eg, elevated liver enzymes or international normalized ratio).
•Moderate to severe tricuspid regurgitation.
•Reduced RV systolic function by qualitative assessment or tricuspid annular plane systolic excursion (TAPSE) <1.4 cm/s .
•Ongoing or recent use of inotropes or temporary MCS devices.
Patients who have one or more of these risk factors are at risk for RV dysfunction after LVAD placement. Risk models that predict RV failure after LVAD placement have been proposed, but they lack accuracy and are not commonly used as the sole determinant of RV failure [8,9].
●Valve dysfunction – For patients who will undergo placement of a LVAD, normal or near normal function of the aortic valve is required, and abnormal function of the other valves may preclude or increase the risk of LVAD implantation.
•Aortic or pulmonic valve – In the presence of aortic valve regurgitation and LVAD support, blood can flow from the systemic circulation into the LV during diastole, which prevents the LVAD from unloading the LV. Thus, patients who will undergo durable MCS device placement with a LVAD must have normal or near-normal function of the aortic valve, and patients with more than mild aortic insufficiency should have a plan for surgical correction at the time of implant (ie, by aortic valve replacement with a bioprosthesis or oversewing of the aortic valve). Patients with aortic valve regurgitation that cannot be surgically repaired can undergo aortic valve bioprosthetic replacement.
Similar to aortic valve abnormalities, pulmonic valve abnormalities must be addressed if a VAD will be placed as an RV assist device (RVAD).
•Tricuspid valve – The presence of tricuspid valve regurgitation increases the risk of RV dysfunction after LVAD placement (see above). Whether tricuspid regurgitation represents a contraindication to LVAD placement or requires surgery at the time of LVAD implant is determined by the overall risk of RV failure and by the risk of tricuspid repair. (See 'Ancillary surgery during device placement' below.)
•Mitral valve – In the presence of a LVAD, blood must flow from the left atrium to the LV apex. Thus, mitral stenosis can prevent unloading of the left atrium, and moderate or severe mitral valve stenosis must be corrected at the time of LVAD implant. In patients who cannot undergo mitral valve surgery at the time of implant, moderate or severe mitral stenosis is a contraindication to LVAD support.
Mitral valve regurgitation is not a contraindication to LVAD placement; LVADs continuously unload the LV, which reduces mitral regurgitation and the effects of mitral regurgitation (ie, reduces left atrial pressure).
•Prosthetic valves – The presence of a prosthetic valve in the mitral or aortic position can increase the risk of stroke during LVAD support . In general, the presence of a mitral or aortic valve bioprosthesis or a mechanical mitral valve is a relative contraindication to LVAD placement. A mechanical aortic valve is an absolute contraindication to LVAD placement unless replaced with a bioprosthetic aortic valve, fixed in a closed position with sutures, or sewn over with a patch at the time of LVAD implantation.
●Rhythm disorders – For some patients, durable MCS placement is the treatment of choice for severe rhythm disorders (eg, ventricular tachycardia). However, patients who undergo LVAD placement require normal function of the RV, which can be diminished by ongoing ventricular tachycardia. Thus, patients with a high burden of ventricular tachycardia may require additional therapy for ventricular tachycardia at the time of LVAD surgery (eg, surgical ablation) or following LVAD surgery (eg, antiarrhythmic therapy, catheter-based ablation).
In general, atrial arrythmias are not a contraindication to VAD placement, though patients with atrial fibrillation who undergo VAD placement have an increased risk of stroke .
●Aortic calcification – Surgery for durable MCS device placement requires anastomosis of the device to the aorta. All patients undergoing durable MCS device placement should have an assessment for calcification of the great vessels with a chest radiograph or chest computed tomography (CT). Typically, the cardiac surgeon will assess whether the presence of aortic calcification represents a contraindication to durable MCS device placement.
●Cerebrovascular and peripheral vascular disease – Patients who undergo durable MCS device placement are at risk for stroke and peripheral vascular events during the initial implant surgery (eg, limb ischemia) and have an increased risk of stroke after device implantation. Thus, all patients under evaluation for durable MCS device placement should have an initial assessment with a focused history and neurologic examination, carotid ultrasonography, and ankle-brachial index measurement. Additional testing with brain CT or lower extremity ultrasound may be necessary if the initial evaluation reveals abnormalities.
The presence of prior stroke, carotid artery stenosis, or severe peripheral vascular disease increase the risk of durable MCS device placement. Patients who have a severe stroke with residual motor dysfunction or peripheral vascular disease that results in an inability to ambulate or operate a durable MCS device have a contraindication to durable MCS device placement in most programs, while patients with lesser degrees of morbidity from a prior stroke or peripheral vascular disease are assessed by each center to determine whether the effects of their disease pose a contraindication to durable MCS device placement.
Noncardiac assessment — The noncardiac assessment is focused on identifying conditions that pose a risk to the patient during the perioperative period or during long-term phase of care. In addition to any other conditions that may be present (eg, cancer), we typically assess the function of the following organs as part of routine evaluation:
●Lung function – The presence of severe pulmonary disease can lead to death, postoperative complications (eg, pneumonia, prolonged intubation), or create a noncardiac exercise limitation. For all patients undergoing evaluation for long-term MCS device surgery, the preoperative assessment of pulmonary disease includes a chest radiograph and pulmonary function tests.
In general, contraindications to VAD placement include:
•Dependence on supplemental oxygen.
•Pulmonary limitation to exercise capacity.
•Forced expiratory volume in one second (FEV1) <1 L or diffusing capacity for carbon monoxide (DLCO) <25 percent of predicted that is not attributable to HF.
This approach to lung assessment is based on our experience; there are no high-quality studies that describe the association between lung function and VAD implantation outcomes.
●Kidney function – Patients who undergo durable MCS placement and develop kidney injury are more difficult to manage in the perioperative period, and patients who develop kidney failure that requires dialysis are at high risk of device infection and may not be able to receive outpatient dialysis due to the specialized care required during dialysis (eg, blood pressure monitoring, management of VAD alarms). Severe kidney injury (acute and chronic) associated with long-term MCS occurs in approximately 14 percent of patients [12,13].
In patients with advanced HF who may undergo long-term MCS device placement, we evaluate for the cause, severity, and reversibility of kidney dysfunction. Thus, the preoperative assessment of kidney function includes screening for chronic conditions associated with progressive kidney disease (eg, diabetes, polycystic kidney disease), signs of irreversible kidney disease (eg, proteinuria ≥1 g/day), and a hemodynamic assessment. These factors are used to estimate the likelihood of short-term and long-term kidney disease.
•Minimal kidney disease without risk factors for chronic kidney disease – In patients with minimal kidney disease (eg, estimated glomerular filtration rate [eGFR] >50 mL/min/1.73 m2) who are at low risk of acute or chronic kidney dysfunction (ie, do not have a progressive kidney disorder, do not have proteinuria, have normal kidney size), the risk of severe acute or chronic injury is average and is not a contraindication to long-term MCS device placement.
•Moderate kidney disease with risk factors for chronic kidney disease – If one or more of the following risk factors for acute or chronic kidney disease are present, the risk of acute or chronic injury is above average and may constitute a contraindication to long-term MCS device placement:
-Preexisting chronic kidney disease with eGFR ≤50 mL/min/1.73 m2 not caused by hypoperfusion from HF.
-Presence of a disease that may lead to progressive renal dysfunction or increase the risk of acute kidney injury (eg, diabetes, polycystic kidney disease).
-Signs of irreversible kidney disease (ie, proteinuria, reduced kidney size by ultrasound).
•Severe kidney disease – If the patient has an eGFR <30 mL/min/1.73 m2 despite optimal therapy or the patient is receiving dialysis and the probability of renal recovery is low (ie, not solely due to HF), the risk of complications from kidney disease is high and MCS device placement is typically contraindicated.
●Liver function – Some patients with chronic HF can develop transient congestive hepatopathy or more permanent forms of liver injury (eg, liver fibrosis, cirrhosis) that increase the risk of intra- and postoperative bleeding and that threaten long-term survival.
To evaluate liver function, we obtain liver function tests, and if abnormal, we obtain further screening with an abdominal ultrasound. If the abdominal ultrasound is abnormal (eg, rough echotexture, signs of portal hypertension), further assessment with a liver biopsy is often obtained if the information from a biopsy is expected to alter the decision to provide long-term MCS.
•Acute reversible liver injury – Patients with mild cholestasis or transaminitis attributable to hypoperfusion from HF should undergo management to reverse the effects of acute liver injury before proceeding with MCS device implantation.
•Chronic liver injury – Patients with evidence of chronic liver injury should be evaluated for the cause and severity of liver dysfunction. Patients with liver fibrosis and preserved liver function have a relative contraindication to MCS device implantation, while patients with cirrhosis or liver fibrosis with signs of advanced liver dysfunction or portal hypertension have an absolute contraindication to MCS device implantation. Single-center studies suggest that the degree of liver fibrosis and other signs of liver dysfunction (eg, Model for End-Stage Liver Disease [MELD] score) can be used to assess the risk of VAD placement [14-16].
●Bleeding risk assessment – Patients with long-term MCS devices undergo systemic anticoagulation with heparin beginning shortly after surgery and are maintained on oral anticoagulation with a vitamin K antagonist (eg, warfarin) throughout the duration of MCS. In patients undergoing evaluation for long-term MCS surgery, we obtain a complete blood cell count, iron studies, protime, and prothrombin time. The following are relative contraindications to MCS surgery:
•History of warfarin intolerance or significant and untreatable bleeding with oral anticoagulation.
•Thrombocytopenia (ie, platelet count less than 100,000/microL).
•Microcytic anemia or iron deficiency without a clear explanation.
•Type 2 heparin-induced thrombocytopenia. (See "Management of heparin-induced thrombocytopenia (HIT) during cardiac or vascular surgery".)
Psychosocial assessment — Patients who undergo long-term MCS device implantation must be able to manage a complex regimen of appointments and testing, be capable of routine and emergency device operation, and have a companion who can assist with health maintenance and device operation. The approach to evaluation and the definition of sufficient support varies between centers. The absence of any one of the following factors can be an absolute contraindication to MCS device placement :
●Capacity to make decisions related to undergoing MCS surgery.
●Past history of reasonable self-care and adherence to medical recommendations.
●Adequate caregiver support, which generally requires near-constant supervision from an individual whose sole focus is the patient.
●Absence of a substance abuse disorder that may interfere with adherence or directly with medical therapies necessary for device support.
●Stable living situation with readily available power for charging batteries and an environment suitable for driveline dressing changes.
●Adequate financial support and insurance to assure that ongoing care does not create a financial hardship.
In addition to assessing individual characteristics, some programs use the Stanford Integrated Psychosocial Assessment for Transplantation (SIPAT) score as another measure of psychosocial health . This scoring system assesses psychosocial health in the domains of readiness level, social support system, psychological stability and psychopathology, lifestyle, and substance abuse domains. However, there is no clear cutoff for what represents a prohibitively high SIPAT score, and studies of the SIPAT score have arrived at varying conclusions:
●One study of 128 patients who had preoperative SIPAT score calculation found that the SIPAT score was associated with an increased risk of events (adjusted hazard ratio/10-unit increase in SIPAT score 1.31, 95% CI 1.09-1.58) and fewer days alive and outside the hospital (-7.0 days outside the hospital/1-unit increase in SIPAT score; 95% CI -12.7 to -1.3) .
●Another study of 115 patients who underwent bridge to transplantation (BTT) or BTT LVAD placement found that patients with a SIPAT score >20 points had a higher rate of unplanned health-care interactions (adjusted rate ratio 1.6, 95% CI 1.0-2.8) .
Bridge to transplantation — In patients with severe HF who are eligible for heart transplantation, a long-term MCS device can be used as a bridge to transplantation (BTT), which is often referred to as a "BTT strategy." In general, we offer placement of a durable MCS device to patients in whom the risks and benefits of device placement outweigh those of ongoing therapy and if durable MCS support is consistent with the patient’s goals of care. Thus, the decision to place a durable MCS device is influenced by the severity of HF, perioperative risk, likelihood of major complications, patient’s ability to maintain the device, and expected benefit of device therapy on survival and quality of life when compared with any alternative therapies.
●Outcomes among patients with an initial BTT strategy – There are no trials of durable MCS device placement versus continued medical therapy among transplant eligible patients. Examples of studies that describe transplant rates, survival, major complications, and changes in quality of life among patients undergoing BTT with durable MCS devices include:
•A 2021 registry study of United States patients who had a ventricular assist device (VAD) placed as BTT showed one-, two-, and three-year survival of 87, 78, and 71 percent, with a one-year transplant rate of 35 percent and a three-year transplant rate of 56 percent . The rates of complications were not separately reported for patients with a BTT strategy.
•In a substudy of a trial (MOMENTUM) that included 1068 patients randomly assigned to either the HeartMate II VAD or to the HeartMate III VAD, patients who were implanted with the HeartMate III device and whose initial goal was transplantation or BTT candidacy (see below) had a two-year mortality rate of approximately 15 percent and a two-year transplant rate of 40 percent . After 24 months of follow-up, major complications included disabling stroke (4 percent), gastrointestinal bleeding (18 percent), bleeding requiring surgery (7 percent), and pump thrombosis (0.5 percent). After 24 months of follow-up, the average six-minute walk distance improved from 134 m to 332 m.
•A study of patients implanted with an artificial heart reported heart transplantation in 53 percent of patients at one year and death in 34 percent at one year . After six months of follow-up, major complications included stroke (23 percent), major infection (70 percent), major gastrointestinal hemorrhage (20 percent), major device malfunction (7 percent), and device thrombosis (2 percent). Quality of life and functional status were not reported in this study.
Bridge to transplant candidacy — In selected patients who have a contraindication to heart transplantation that may resolve with additional management or as the result of better perfusion afforded by a durable MCS device, MCS therapy can be used as a "bridge to decision" or "bridge to candidacy" (BTD and BTC, respectively). In such patients, the decision to undergo durable MCS device placement is determined by the risks and benefits of device placement compared with ongoing therapy as well as the likelihood that contraindications to transplantation will resolve. Conditions that typically result in a BTC strategy include:
●Substance dependency or use disorders
There are no specific studies that describe the success of the BTC strategy for specific contraindications to transplant. The general outcomes among patients with an initial BTC strategy include the following:
●In one study that included patients initially listed as BTC, 29 percent had been listed for transplant after two years of follow-up. BTC patients who were classified as likely, not likely, or unlikely to be transplantation candidates underwent transplantation at rates of 50 percent, 15 percent, and 2 percent, respectively . At 24 months, survival was 70 percent.
●In the MOMENTUM trial, patients with a BTT or BTC indication were analyzed together; the complication rates and change in quality of life are described above. (See 'Bridge to transplantation' above.)
Destination therapy — Select patients with advanced HF who are not transplant candidates and who are unlikely to become candidates for transplantation may elect to undergo durable MCS placement as "destination therapy" (DT) rather than continue with medical therapy or inotropic therapy. Similar to other indications for long-term MCS, we offer long-term MCS as DT to patients in whom the benefits exceed the risk of therapy.
●Outcomes among patients with an initial DT strategy – Only one trial directly compared durable MCS device support with ongoing medical therapy; this trial used a device that is no longer implanted but showed that patients who received durable MCS support had improved survival compared with patients who received ongoing medical therapy (two-year survival 23 versus 8 percent) . Studies that followed this trial reported improved survival among patients supported with more contemporary devices. Artificial hearts are not approved for use as DT in the United States.
The trials and studies of DT include:
•In a large United States registry, patients implanted with VADs as destination therapy had one-, two-, and three-year survival of 80, 71, and 61 percent, respectively .
•In the subgroup of patients with a DT indication in the more recent MOMENTUM VAD trial, death occurred in approximately 22 percent of patients at two years, and approximately 14 percent of patients initially implanted as DT underwent transplantation . After 24 months of follow-up, major complications included disabling stroke (6 percent), gastrointestinal bleeding (29 percent), bleeding requiring surgery (11 percent), and device thrombosis (2 percent). After 24 months of follow-up, the average six-minute walk distance improved from 137 m to 320 m.
•In one study from a United States registry, approximately 5 percent of patients initially listed as DT had undergone transplant .
•A registry study that reported change in quality of life (visual analog scale [0-100] among patients with a DT VAD found that quality of life improved from approximately 35 points to approximately 75 points .
CHOICE OF DEVICE AND SURGICAL APPROACH
Device types for common patient groups — The presence of biventricular failure and LV dilation typically determine which type of device can be used for durable MCS:
●Predominant left heart failure with left ventricular dilation – In patients with advanced HF due to reduced LV function (HF with reduced ejection fraction) who have LV dilation and are otherwise eligible for long-term MCS, an LV assist device (LVAD) is the device of choice. LVADs are the most common type of durable MCS.
●Biventricular failure – In patients with severe biventricular systolic dysfunction or biventricular diastolic dysfunction (eg, restrictive cardiomyopathy), an artificial heart or placement of two VADs (eg, a left-sided and right-sided VAD [BiVAD]) can be used to provide long-term MCS. Due to patient morbidity at the time of placement and the complexity of biventricular MCS, patients who require a biventricular support typically have worse outcomes than patients who require LVAD support. These devices are intended for use as a bridge to transplant and not as destination therapy.
●Predominant right ventricular failure – An LVAD can be used off-label to treat isolated RV failure as an RV assist device (RVAD). RVADs are not appropriate for use in patients with pulmonary hypertension. Use of an isolated RVAD is rare, and survival after isolated RVAD support is low.
●Types of HF less amenable to MCS – In general, VADs are not designed to treat patients who have severe HF and a nondilated ventricle (eg, systolic HF immediately after myocardial infarction, HF with preserved ejection fraction, hypertrophic cardiomyopathy). In addition, patients who have severe aortic valve disease that cannot be repaired have a contraindication to placement of an VAD. Some patients with these diseases or characteristics may be supportable with an artificial heart.
Specific devices — The choice of a specific durable MCS device is typically determined by the features of the commercially available devices and the adverse event rates associated with the device.
●Ventricular assist devices – The HeartMate III device is the only VAD available for implant. The HeartWare device is no longer available for implant as of 2021 due to concerns of excessive stroke risk, though many patients have this device implanted. The outcomes with the HeartMate III device and HeartWare device are discussed elsewhere. (See 'Indications' above and 'Prognosis and outcomes' below.)
●Artificial hearts – The Total Artificial Heart (TAH) is the only artificial heart available for implant. The outcomes and adverse events associated with the TAH are discussed elsewhere. (See 'Indications' above and 'Prognosis and outcomes' below.)
Surgical approaches — The majority of durable MCS devices are placed via a median sternotomy, and a median sternotomy is the only surgical approach for patients undergoing artificial heart placement. An LVAD may be placed via a lateral thoracotomy incision with or without a mini-sternotomy incision (ie, bithoracotomy approach) . In theory, placement of an LVAD by a bithoracotomy approach may reduce bleeding at the time of surgery and reduce the risk of sternal reentry at the time of heart transplantation, but this approach has not been directly compared with a median sternotomy approach.
Ancillary surgery during device placement — The most common surgeries performed at the time of LVAD implantation are tricuspid valve surgery, mitral valve repair, and aortic valve surgery. The decision to pursue these surgeries is typically determined by the surgeon on a case-by-case basis.
PROGNOSIS AND OUTCOMES
Long-term survival — The long-term survival of patients who undergo durable MCS device placement is dependent on the patient’s characteristics at implant, whether the patient remains eligible for transplant, and the type of device.
●Patients with a ventricular assist device – Randomized trials and large registries report the long-term survival with a ventricular assist device:
•In a randomized trial that compared the HeartMate III device with the HeartMate II device, five-year survival free of a major stroke in the HeartMate III group was 58 percent .
•In a large registry (INTERMACS) that included patients with ventricular assist device (VAD) support, patients with an initial bridge to transplantation or bridge to candidacy implant strategy had five-year survival of 52 and 51 percent, respectively, and patients with an initial destination therapy strategy had a five-year survival of 44 percent .
●Patients with an artificial heart – Outcomes are worse with artificial hearts than with LV assist devices (LVADs), but in some patients with biventricular failure, an artificial heart may be the only option for durable MCS. In a large registry (INTERMACS) that included patients with artificial heart support and that reported outcomes up to two years after implant, 34 percent of patients died, 53 percent had undergone heart transplantation, and 13 percent were alive with their device in place .
Complications — The complications of durable MCS include stroke, major bleeding, major infection, device malfunction/pump thrombosis, and right HF . The risk of complications is based on patient risk factors, long-term management of the patient, and characteristics of specific devices.
●Ventricular assist device adverse events – The major complications of VAD therapy include :
•Stroke (0.12 events per patient-year [EPPY])
•Device malfunction/pump thrombosis (0.18 EPPY)
•Major bleeding (0.5 EPPY)
•Major infection (0.57 EPPY)
●Artificial heart adverse events – Major complications of artificial heart therapy include :
•Stroke (0.6 EPPY)
•Device malfunction (0.2 EPPY)
•Pump thrombosis (0.02 EPPY)
•Major bleeding (1.6 EPPY)
•Major infection (2.0 EPPY)
Recovery — In selected patients who undergo LVAD placement and who are managed with specialized management protocols, recovery of myocardial function allowing LVAD removal is possible, though recovery in unselected patients after LVAD implantation is not common. However, only small numbers of patients have been studied for recovery, and explantation protocols are not available at all LVAD centers.
●In a large series of patients recorded in a national registry (INTERMACs), the rate of LVAD explantation for recovery was one percent .
●In a prospective multicenter study (RESTAGE-HF) of 40 patients with nonischemic cardiomyopathy (NICM) implanted with the HeartMate II who received a protocol of medication and device optimization, 19 patients were explanted. The primary endpoint of LVAD explant within 18 months with freedom from MCS/heart transplantation at one year after explant occurred in 40 percent of patients .
●In a report from a single United Kingdom center that included 20 patients with NICM who were supported with the Heartmate II pump and treated with medical therapy (including the muscle growth agent clenbuterol), 12 patients were explanted . The explanted patients had a one-year transplant- and LVAD-free survival of 83 percent.
SUMMARY AND RECOMMENDATIONS
●Goals of therapy – The primary goal of therapy with a durable mechanical circulatory support (MCS) device is to prolong survival and improve quality of life in patients with advanced heart failure (HF). While durable MCS device therapy can prolong survival and reduce symptoms associated with HF, all patients with a durable MCS device require life-long management of HF and device complications from a specialized team, meticulous self-management, and the continuous support of a dedicated caregiver. (See 'Goals of therapy' above and 'Education on MCS therapy and alternatives' above.)
●Types of devices – There are two basic types of durable MCS devices: left ventricular assist devices (LVADs) that augment blood flow (figure 1 and figure 2) and artificial hearts that completely replace the pumping action of the heart (figure 3). (See 'Types of durable MCS devices' above.)
●Initial evaluation – The evaluation for durable MCS device placement involves many steps and may include invasive testing. Before proceeding with a comprehensive evaluation, we review the following:
•Confirm the diagnosis of advanced HF (see 'Diagnosis of advanced heart failure' above)
•Educate the patient on MCS therapy and its alternatives (see 'Education on MCS therapy and alternatives' above)
•Review the goals of care (see 'Goals of care' above)
•Establish heart transplantation eligibility (see 'Eligibility for heart transplantation' above)
●Evaluation – While the exact criteria for relative and absolute contraindications vary between centers, the common goal of presurgical evaluation is to identify risk factors for adverse events. The evaluation includes:
•Cardiovascular assessment (see 'Cardiovascular assessment' above)
•Noncardiac assessment (see 'Noncardiac assessment' above)
•Psychosocial assessment (see 'Psychosocial assessment' above)
●Choice of strategy – The initial therapeutic strategy is one of the following:
•Bridge to transplantation – Patients with an initial bridge to transplantation (BTT) strategy undergo durable MCS device placement with the intent of eventual heart transplantation. (See 'Bridge to transplantation' above.)
•Bridge to transplant candidacy – Patients with a bridge to candidacy (BTC) strategy undergo durable MCS device placement with the intent of resolving barriers to transplantation followed by transplantation. (See 'Bridge to transplant candidacy' above.)
•Destination therapy – Patients with a destination therapy (DT) strategy undergo durable MCS device placement without the prospect of eventual transplantation. (See 'Destination therapy' above.)
●Device types for common patient groups – The presence of LV failure, right ventricular failure, and LV dilation typically determine which type of device is most appropriate. (See 'Device types for common patient groups' above.)
●Prognosis and outcomes
•Long-term survival – The long-term survival with a durable MCS device depends on the patient characteristics and the type of device. (See 'Long-term survival' above.)
•Complications – Common device-related complications include stroke, device malfunction, bleeding, and infection. (See 'Complications' above.)
•Recovery – In selected patients who undergo LVAD placement and who are managed with specialized management protocols, recovery of myocardial function allowing LVAD removal is possible, though recovery in unselected patients after LVAD implantation is not common. (See 'Recovery' above.)
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