Medical Management of Patients With a Left Ventricular Assist Device for the Non-Left Ventricular Assist Device Specialist

JACC: HEART FAILURE

VOL.

ª 2017 BY THE AMERICAN COLLEGE OF CARDIOLOGY FOUNDATION

-, NO. -, 2017

ISSN 2213-1779/$36.00

PUBLISHED BY ELSEVIER

http://dx.doi.org/10.1016/j.jchf.2017.06.012

STATE-OF-THE-ART REVIEW

Medical Management of Patients With a Left Ventricular Assist Device for the Non-Left Ventricular Assist Device Specialist Adam D. DeVore, MD, MHS,a,b Priyesh A. Patel, MD,a Chetan B. Patel, MDa,b

ABSTRACT More than 2,400 continuous-flow left ventricular assist devices (LVADs) are implanted each year in the United States alone. Both the number of patients living with LVADs and the life expectancy of these patients are increasing. As a result, patients with LVADs are increasingly encountered by non-LVAD specialists who do not have training in managing advanced heart failure for general medical care, cardiovascular procedures, and other subspecialty care. An understanding of the initial evaluation and management of patients with LVADs is now an essential skill for many health care providers. In this State-of-the-Art Review, we discuss current LVAD technology, summarize our clinical experience with LVADs, and review the current data for the medical management of patients living with LVADs. (J Am Coll Cardiol HF 2017;-:-–-) © 2017 by the American College of Cardiology Foundation.

DURABLE LEFT VENTRICULAR ASSIST DEVICE USE IN 2017

As the LVAD patient population increases, so does the need for access to general medical and cardiovascular care. Providing care for patients with

Over the past decade, the use of continuous-flow left

continuous-flow LVADs is no longer restricted to

ventricular assist devices (LVADs) has increased

advanced HF specialists; however, there are limited

significantly. In the United States alone, approxi-

data and guidelines to assist non-LVAD specialists in

mately

annually

caring for these patients. In this State-of-the-Art

compared with only 459 in 2008 (1). More than 16,000

Review, we discuss current LVAD devices and

patients have received a continuous-flow LVAD in the

equipment and summarize initial management stra-

United States (2). These devices are a life-saving op-

tegies to assist non-LVAD specialists in providing care

tion for advanced heart failure (HF) patients who are

for these complex patients.

2,400

LVADs

are

implanted

either not eligible for a heart transplant or too ill to safely wait for a transplant on medical therapy alone.

CURRENT DURABLE LVADs AND EQUIPMENT

Survival post-LVAD implantation also continues to improve with 1-month survival estimates at 95%, and

There are currently 2 durable (i.e., able to be dis-

1- and 2-year survival estimates at 80% and 70%,

charged home) LVADs approved for adults by the U.S.

respectively (1).

Food and Drug Administration: the HeartMate II left

From the aDepartment of Medicine, Duke University School of Medicine, Durham, North Carolina; and the bDuke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina. The manuscript was funded by the Duke Clinical Research Institute. Dr. DeVore has received research funding from American Heart Association, Amgen, and Novartis; and consults for Novartis. Dr. C.B. Patel consults for Heartware/Medtronic and Thoratec/Abbott. Dr. P.A. Patel has reported that he has no relationships relevant to the contents of this paper to disclose. Manuscript received April 4, 2017; revised manuscript received June 11, 2017, accepted June 11, 2017.

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Management of LVAD for the Non-LVAD Specialist

ABBREVIATIONS

ventricular assist system (St. Jude Medical,

accurate in the case of physiologic derangements

AND ACRONYMS

St. Paul, Minnesota) and the HeartWare

(e.g.,

ventricular assist device system (HVAD)

including

(HeartWare, Framingham, Massachusetts).

controller measures temporal power fluctuations to

HeartMate 3 (St. Jude Medical) was recently

give an estimate of pulsatility through the pump,

compared to HeartMate II in a large, ran-

termed pulsatility index for HeartMate devices and

HF = heart failure

domized

represented graphically as the HVAD pump flow

LV = left ventricle

have improved outcomes at 6 months,

waveform for the HeartWare device. Table 1 de-

LVAD = left ventricular assist

although

scribes typical values for pump parameters informed

device

investigational (3).

AV = aortic valve BP = blood pressure CT = computed tomography

MAP = mean arterial pressure

clinical the

trial

device

and

found

currently

to

remains

by

This review considers the management of

aortic

clinical

insufficiency

pump

trial

or

thrombosis).

data

and

LVAD

dysfunction

Additionally,

experience

at

the

our

institution.

HeartMate II, HeartWare, and HeartMate 3. These

KEY DIFFERERNCES AMONG CURRENT LVADs. Cur-

pumps

are

rent generation LVADs have analogous components,

differ

in

technical

design,

but

all

continuous-flow pumps and have the following

but there are clinically important differences among

analogous components: 1) an inflow cannula that is

devices. HeartMate II is an axial flow pump with a

surgically implanted into the left ventricular (LV)

larger profile than HVAD and HeartMate 3, conse-

apex, serving as a conduit for blood from the LV to the

quently implantation in a surgically created pre-

pump; 2) a pump enclosure which houses an impeller

peritoneal pocket is required (Online Figure 1).

that circulates blood; 3) an outflow graft that carries

HeartMate 3 and HVAD are centrifugal pumps with

blood from the pump to the systemic circulation; and

smaller profiles and are implanted directly opposing

4) a surgically tunneled driveline that connects the

the heart (Online Figures 2 and 3). HVAD and Heart-

pump to an external controller that operates and

Mate 3 provide more accurate cardiac output esti-

monitors the pump function. The external controller

mates during normal operation, given the centrifugal

is connected by 2 power cables to a battery powered

design, and by using the patient’s manually entered

source or a power module connected to an AC source

hematocrit to estimate the serum viscosity. Impor-

while batteries are charging. Batteries can last up to

tantly, centrifugal flow pumps (i.e., HVAD and

12 h, and remaining battery life is displayed on the

HeartMate 3) have a larger change in flow for a given

external controller. The pump will function properly

pressure gradient change across the pump (i.e.,

if only 1 power cable is connected to the external

afterload minus preload) than the axial flow Heart-

controller, but an alarm will sound. Additional device

Mate II. Therefore, centrifugal flow pumps are more

peripherals include a backup controller, spare batte-

sensitive to changes in preload and afterload, and

ries, chargers, and brand-specific system monitors

controlling hypertension is a key element of normal

that are used to program, interrogate, and trouble-

centrifugal flow pump function.

shoot LVADs (Online Figures 1 to 5).

Both the HVAD and HeartMate 3 have automated

BASIC LVAD FUNCTION. LVADs move blood from the

speed modulation capabilities to enhance washing of

LV apex to systemic circulation in a continuous

the pump and allow possible intermittent ejection

(nonpulsatile) manner. Pump speed is the funda-

through the native aortic valve (AV). These rapid

mental parameter that the provider can alter. As

speed modulations, termed “Artificial Pulse” for

pump speed increases, the impeller within the pump

HeartMate 3 and “Lavare Cycle” for HVAD (available

housing spins more rapidly and circulates a greater

through software update in Europe), entail slowing

volume of blood, thereby increasing LV unloading

the impeller and then accelerating the pump speed to

and cardiac output. Contemporary pump design and

the set speed or higher. Automatic speed modulation

operating software are unable to automatically

may have benefits in preventing pump thrombosis for

modulate speed or cardiac output based on physio-

HeartMate 3, as well as reducing AV insufficiency and

logic demand; therefore, they will operate at the

stroke for HVAD (3,4).

speed the provider sets, consuming as much power as needed to maintain that speed.

PATIENT ASSESSMENT

The system controller monitors power consumption and estimates cardiac output based on speed

Most clinical encounters will require an assessment for

and power consumption. This estimated flow is re-

normal LVAD function and an assessment of heart rate

ported on the system controller in liters per minute.

and blood pressure (BP). Later, we discuss unique as-

Notably, the flow is an estimated value based on

pects of a patient assessment and common and/or

power consumption at given speeds and may not be

serious

LVAD

complications.

Each

complication

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should also be evaluated with a targeted patient history, physical examination, and initial evaluation. HISTORY

AND

PHYSICAL

EXAMINATION. Unique

aspects of the patient assessment include evaluation

T A B L E 1 Typical LVAD Operating Parameters

Typical speed, rpm* Speed adjustment increment, rpm/increment

HeartMate II

HeartMate 3

HVAD

8,000–10,000

5,000–6,000

2,400–3,200

200

100

20 4–6

for normal LVAD function and for common (some-

Flow, l/min

4–7

4–6

times occult) complications. The history should

Power, W

5–8

4.5–6.5

3–7

include recent device parameters and alarms (Central

Pulsatility index (or HVAD, peak to trough)

5–8

3.5–5.5

2–4 l/min/beat

Illustration), symptoms of infection (including of the driveline) or HF, and signs of hemoglobinuria (e.g., dark urine) that could be a harbinger of LVAD thrombosis. We also evaluate tolerability to antithrombotic medications (most commonly aspirin and warfarin) and ask about signs and symptoms sug-

*Speeds at the lower range or below the clinical ranges shown above indicate a low level of support is needed and should prompt investigation of native contractility. Speeds above or near the high range described above should prompt investigation for adequate left ventricular unloading, including the possibilities of LVAD dysfunction or native valvular disease that could be affecting unloading. HVAD ¼ HeartWare ventricular assist device (system); LVAD ¼ left ventricular assist device; rpm ¼ revolutions per minute.

gestive of melena, because chronic bleeding from arteriovenous malformations in the gastrointestinal tract is a common complication. examination

for infection in patients, careful attention should be

include assessments of pulse, BP, auscultation of the

given to the driveline (Online Figures 1 to 3), as most

LVAD, examination of the driveline and device con-

LVAD infections involve the percutaneous driveline

Unique

aspects

of

the

physical

nections, and device interrogation for device param-

(6). Typical examination findings of a driveline

eters and alarms. A key aspect of measuring pulse and

infection include drainage or pus, presence of an ab-

BP is understanding that the degree of arterial pul-

scess, or cellulitis.

satility depends on multiple factors, as follows: 1)

ROUTINE LABORATORY TESTING AND IMAGING

underlying LV contractility; 2) AV function (i.e., the

STUDIES. In addition to usual laboratory testing,

AV can sometimes be intentionally oversewn for

most patients with LVADs require screening evalua-

management of aortic insufficiency); 3) LVAD pump

tion for anemia and subclinical hemolysis. Screening

speed; and 4) LVAD preload and afterload. For

for hemolysis may be done by either plasma-free

example, pulsatility decreases at increased pump

hemoglobin (hemolysis defined by concentration of

speeds (Central Illustration), consequently, assess-

>40 mg/dl) or lactate dehydrogenase (hemolysis is

ments of heart rate often require telemetry or elec-

typically defined as values 2.5
the upper limit of

trocardiography instead of palpation of a pulse, which

normal, >600 IU, or significantly above baseline)

is often absent. Similarly, current technology for

(5,7).

noninvasive BP measurement can be unreliable when

Multimodal imaging capabilities are essential for

there is decreased pulsatility, so Doppler ultraso-

the initial evaluation of LVAD patients, especially

nography is often necessary to measure BP. To mea-

echocardiography due to its ease of access and

sure, a manual BP cuff is inflated to occlude the

portability. Echocardiography can provide important

brachial artery, and a Doppler ultrasound probe is

insights regarding acquired valvular disease, inflow

used to auscultate the brachial artery on the medial

cannula position and orientation, right and left ven-

aspect of the antecubital fossa as the cuff is deflated.

tricular function, filling pressures, and effectiveness

The pressure at which the sound of blood flow returns

of LV unloading. Real-time feedback from echocar-

to the brachial artery is recorded and best described

diography is key for diagnosing and troubleshooting

as an opening or Doppler pressure, although in prac-

LVAD dysfunction, including imaging the response to

tice it is often called a mean arterial pressure (MAP). If

speed adjustments, provocative maneuvers (e.g.,

a patient has significant pulsatility, then the opening

Valsalva and positional changes), and pacing adjust-

pressure likely represents systolic BP. If there is low

ments. For example, newly identified AV opening or

pulsatility,

a

severe mitral regurgitation is suggestive of inade-

reasonable estimate of the MAP. The typical MAP

quate LV unloading from the pump, potentially from

target is #80 mm Hg to reduce stroke risk and mini-

a speed that is set too low or from LVAD dysfunction.

mize LVAD afterload (5).

Adjustment to a higher LVAD speed under echocar-

then

the

opening

pressure

gives

Cardiac auscultation can reveal the “hum” of an

diographic guidance can provide diagnostic informa-

LVAD, which is important if there is any concern for

tion regarding pump dysfunction while optimizing

pump dysfunction, as the hum can vary depending on

unloading (8). Importantly, echocardiography has

pump stress or pump stoppage. If there is any concern

inherent limitations due to acoustic shadowing from

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C E NT R AL IL L U STR AT IO N Unique Aspects of Evaluating a Patient With an LVAD

DeVore, A.D. et al. J Am Coll Cardiol HF. 2017;-(-):-–-.

Key aspects of evaluating a patient with an LVAD include assessing recent device parameters and alarms and for common and/or serious complications such as infection, heart failure, LVAD thrombosis, and gastrointestinal bleeding. The figure also displays the impact of continuous-flow LVAD speed on blood flow pulsatility. As LVAD speeds increase, more blood flows though the LVAD instead of being ejected through the aortic valve. Therefore, at higher pump speeds, there is a lower pulse pressure. Lower pulsatility has an impact on the assessment of pulse and blood pressure on physical examination. See Online Figures 1 to 5 for brand-specific images of device components. GI ¼ gastrointestinal; HF ¼ heart failure; HVAD ¼ HeartWare ventricular assist device; LVAD ¼ left ventricular assist device; RPM ¼ revolutions per minute.

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LVAD components, particularly for patients with apically-positioned centrifugal flow pumps (i.e.,

T A B L E 2 Suggested Approach to Suspected LVAD Infection

Initial Evaluation

HVAD or HeartMate 3), which can significantly limit 2-dimensional and spectral Doppler analysis from

Initial Management

Obtain local wound culture

Remove driveline dressing. Do not express wound immediately and clean exit site (typically with chlorhexidine soap). Irrigate the area until clean and then dry the area before expressing drainage and collecting specimen.

Obtain blood cultures. Consider other evaluations (e.g., urine culture if non-LVAD-related infection is also suspected).

Review prior culture data and consider empirical antibiotic therapy after blood cultures are obtained. The most common pathogens are Gram-positive organisms (e.g., coagulase-negative staphylococci and S. aureus), although Gram-negative organisms, fungal infections, and polymicrobial infections also occur. Many patients will also need warfarin held and bridging with unfractionated heparin if surgical intervention is necessary.

apical imaging windows. Comprehensive guidelines for echocardiographic imaging of LVAD patients are also available (9). Electrocardiogram-gated

computed

tomography

(CT) angiography and nuclear imaging also play important roles in the evaluation of LVAD patients. Contrast-enhanced gated CT scans timed for opacification of the LVAD inflow and outflow cannulas allow excellent visualization of LVAD components outside of the metallic pump housing, particularly the outflow graft, and can help with the diagnosis of

extent of infection.

If percutaneous driveline infection is Depending on results, surgical evaluation for driveline debridement and infectious suspected, obtain a chest and abdomen diseases consultation may be needed. ultrasonogram or CT to assess for abscess and/or driveline stranding. If bacteremia or sepsis is present, assess for the source of bacteremia by using a chest and abdomen CT and transthoracic or transesophageal echocardiogram.

COMMON AND/OR SERIOUS

CT ¼ computed tomography; LVAD ¼ left ventricular assist device.

cannula malposition and outflow graft narrowing, kinking, or thrombosis (10). In cases of suspected infection, nuclear imaging with radioisotope-tagged white blood cells can help identify the presence and

LVAD COMPLICATIONS Adverse events with contemporary, continuous-flow LVADs are

lower

than older,

pulsatile

LVADs,

The evaluation for infection includes driveline drainage

culture,

blood

cultures,

and

imaging

although the rate of adverse events remains unac-

(Table 2). In particular, blood cultures are important to

ceptably high (11). More than 50% of patients are

evaluate for occult bloodstream infections, because

readmitted for adverse events in the first 6 months

LVAD patients can present with atypical signs and

post-LVAD implant, and patients experience an

symptoms. Imaging the internal course of the driveline

average of 3.5 adverse events (most commonly

up to the pump can be accomplished with ultraso-

bleeding, infection, and/or arrhythmia) in the first

nography or CT. We prefer CT scans with or without

year post-implantation (1). By 2 years post-implant,

contrast to evaluate the extent of driveline and/or

approximately 80% of patients have experienced a

pump pocket infections. The most common pathogens

major adverse event (1). We focus here on common

are Gram-positive skin flora (e.g., coagulase-negative

and/or serious complications that occur outside of the

staphylococci and Staphylococcus aureus), although

perioperative period. The reader may refer to other

Gram-negative organism (e.g., Pseudomonas spp.

reviews and guidelines that discuss perioperative

and Enterobacteriaceae), fungal, and polymicrobial

medical management and complications (5,12). The

infections also can occur (6,14,15).

management of LVAD complications should occur in

NONSURGICAL BLEEDING. Nonsurgical bleeding is a

consultation with advanced HF providers, although

common complication after LVAD implantation and a

the following discussion may assist with initial eval-

familiar cause for hospital readmission (16). There are

uation and management.

multiple

LVAD INFECTIONS. Most LVAD infections involve

example: 1) use of antithrombotic therapy; 2) acquired

reasons

for

nonsurgical

bleeding,

for

the percutaneous driveline (6) and can range in

coagulopathy, especially von Willebrand factor defi-

severity from a local skin infection to a systemic

ciency from degradation of high-molecular-weight von

infection that involves the LVAD pump. Patients and

Willebrand factor multimers as they move through and

caregivers are educated about specific instructions for

are sheared by the pump; and 3) formation of arterio-

regular dressing changes and monitoring for signs

venous malformations in the gastrointestinal tract,

and symptoms of infection at the driveline exit site.

nasopharynx, brain, and other tissues, which seems

Nevertheless, data suggest that many driveline in-

related to continuous blood flow and an associated

fections are unavoidable, resulting from trauma to

abnormal regulation of angiogenic factors (17).

the driveline exit site (e.g., accidentally dropping a controller or battery pack) (13).

Our general approach to treatment is to hold antithrombotic

therapy,

control

the

source

of

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F I G U R E 1 Evaluation and Management of Gastrointestinal Bleeding

Proposed approach to the initial evaluation and management of gastrointestinal bleeding. CT ¼ computed tomography; GI ¼ gastrointestinal; LVAD ¼ left ventricular assist device; RBC ¼ red blood cell.

bleeding, and transfuse blood products as needed

with atrial arrhythmias (20,21). Approximately one-

(while recognizing the potential for antibody sensiti-

half of all LVAD patients have atrial fibrillation in

zation

trans-

observational studies (22), and as many as 22% to 59%

plantation). Patients rarely need active reversal of

have reported ventricular arrhythmias (23). Impor-

antithrombotic

life-

tantly, many LVAD patients may tolerate ventricular

intracranial

tachycardia for hours due to continuous hemody-

hemorrhage. Gastrointestinal bleeding related to

namic support provided by the LVAD. Our initial

arteriovenous malformations is the most common

evaluation of LVAD patients with ventricular tachy-

presentation for nonsurgical bleeding and can occur at

cardia is similar to that of patients without an LVAD,

any time after implantation (18). Figure 1 outlines our

including an assessment of hemodynamic stability

general approach to evaluation and management.

with vital signs and obtaining an electrocardiogram if

Notably, many patients develop recurrent gastroin-

able. Cardioversion can be safely performed for pa-

testinal bleeding, and a review of prior endoscopic

tients requiring urgent therapy by placing external

procedures is an important aspect of the initial eval-

defibrillator pads in the usual locations, although

uation, although the diagnostic and therapeutic yield

pads should not be placed over the LVAD pump.

of

There is no need to stop or disconnect the LVAD

in

threatening

patients

considered

therapies,

hemorrhage

endoscopy

remains

for

unless such

high

heart

there as

with

is

repeated

in-

terventions (19).

before external cardioversion.

ATRIAL AND VENTRICULAR ARRHYTHMIAS. Both

cardia, the mechanism of arrhythmia is important to

When evaluating a patient with ventricular tachyatrial and ventricular arrhythmias are common post-

consider. For example, contact from the inflow can-

LVAD implantation. Approximately 20% of patients in

nula to the LV can occur when the LV is completely

the HeartMate II Destination Therapy trial presented

decompressed by continuous inflow, possibly from

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F I G U R E 2 Neurological Emergencies

Proposed approach to neurologic emergencies. ICH ¼ ischemic hemorrhage; LDH ¼ lactate dehydrogenase; SDH ¼ subdural hematoma; other abbreviations as in Figure 1.

dehydration or an excessively high speed (24).

secure, reviewing LVAD alarms, and evaluating LVAD

This scenario can be clarified by a history suggestive

flow and patient stability. Management of suspected

of hypovolemia and confirmed by echocardiogram

electrical malfunction typically requires consultation

and/or LVAD interrogation, which may demonstrate

with an LVAD specialist. If the provider and patient

low pulsatility index (HeartMate devices) or low

are put in the position of attempting to change a

HVAD

flow

waveform

(HeartWare

device).

In

controller, which results in an obligatory temporary

contrast, another possible mechanism is scar related

LVAD stoppage, then one must first determine the

to myocardial fibrosis. The initial treatment strategies

patient’s hemodynamic dependence on LVAD support

for these 2 scenarios can be quite different, ranging

(e.g., patients with an oversewn AV are more depen-

from optimization of fluid status to initiation of

dent on LVAD flow than patients with a normal func-

antiarrhythmic medications.

tioning AV). Controller exchange should be performed quickly by well-trained personnel to prevent compli-

LVAD MALFUNCTION OR FAILURE. LVAD malfunc-

cations related to lack of native ejection for these

tion or failure may result from a variety of causes,

patients during temporary pump stoppage.

including electrical malfunction and thrombosis. Me-

LVAD thrombosis can occur on the inflow cannula,

chanical pump failure is less common in continuous-

pump, or outflow graft. HeartMate II was noted to

flow

LVADs.

have higher-than-expected rates of thrombosis in a

Electrical malfunction typically presents with LVAD

devices

than

previous

generation

large observational study (25) and higher rates of

alarms or pump stoppage, and initial management

device malfunction requiring surgical replacement in

involves checking to ensure device connections are

clinical trials compared with HVAD (16.2% vs. 8.8%,

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F I G U R E 3 HF Profiles

Proposed heart failure profiles to guide initial evaluation and management. For refractory cases, consider extracardiac causes of volume overload such as a peripheral shunt, cirrhosis, or nephrotic syndrome. AI ¼ aortic valve insufficiency; BP ¼ blood pressure; DOE ¼ dyspnea on exertion; HF ¼ heart failure; IVC ¼ inferior vena cava; JVP ¼ jugular venous pressure; LV ¼ left ventricular; LVEDD ¼ left ventricular end-diastolic dimension; MCS ¼ mechanical circulatory support; MR ¼ mitral regurgitation; PCWP ¼ pulmonary capillary wedge pressure; PI ¼ pulsatility index; PND ¼ paroxysmal nocturnal dyspnea; RHC ¼ right heart cardiac catheterization; RV ¼ right ventricular.

respectively) (26) or HeartMate 3 (7.7% vs. 0.7%,

an annual incidence of approximately 9% (27).

respectively) (3). Thrombosis presents in various

Ischemic and hemorrhagic strokes cause significant

degrees of severity, including asymptomatic eleva-

morbidity and are associated with high rates of mor-

tions in plasma-free hemoglobin or lactate dehydro-

tality (28). The risk of stroke and death among patients

genase, clinical evidence of hemolysis, LVAD alarms

appears to be bimodal with highest risks in the peri-

for changes in power or flow, and isolated left-sided

operative period and increasing approximately 1 year

or biventricular HF. Initial management includes

later (29). Figure 2 displays our approach to managing

evaluating

strategies

neurological emergencies. Similar to stroke in non-

including international normalized ratio and anti-

LVAD patients, early patient recognition and urgent

platelet therapy dose, stabilizing the patient; and

medical evaluation, including brain and vascular im-

in select cases, planning for emergent surgical

aging, are key steps in the evaluation. One must also

interventions or thrombolytic agents. Echocardio-

consider whether LVAD thrombosis (i.e., evaluate

graphic ramp studies (8) may also be used to evaluate

LVAD pump parameters, evaluate for hemolysis, and

LVAD dysfunction related to thrombosis, and CT

obtain echocardiography) could be an embolic source

angiography may be performed to evaluate the

in patients with ischemic or hemorrhagic stroke.

current

antithrombotic

outflow graft.

HEART FAILURE. Acute right ventricular failure post-

NEUROLOGICAL EMERGENCIES. Ischemic and hem-

LVAD implantation is common and well described,

orrhagic strokes remain the most dreaded adverse

including associated risk factors and outcomes

events following LVAD implantation, occurring with

(30–32). Heart failure that occurs late after LVAD

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implantation is a distinct entity with an emerging

potential dislodgement of the inflow tract/outflow

evidence base, especially for late right HF (33–35).

graft during compressions; and 4) the initial patient

In an analysis of data from the HeartMate II Destina-

survey should consider the previously-mentioned

tion Therapy trial, patients with late right HF had

complications (e.g., infection, bleeding, neurological

worse outcomes at 2 years than those without,

emergencies).

including worse quality of life, poorer functional capacity, increased rehospitalizations (median: 6 [range 2 to 19] vs. 3 [range 0 to 27], respectively), and decreased rate of survival (58  8% vs. 71  2%, respectively) (35). We propose 3 patient profiles as a conceptual framework to guide initial evaluation and management of LVAD patients presenting with HF (Figure 3). We use the patient’s history and physical examination, an echocardiogram, and/or an invasive hemodynamic

assessment

to

determine

if

HF

is

biventricular, isolated left-sided, or isolated rightsided. We also ensure accurate assessment of the MAP and evaluate for LVAD dysfunction. When evaluating HF, one must understand the role of continuous AV insufficiency, which can develop de novo or from exacerbation of underlying AV pathology and is more common with contemporary, continuous-flow LVADs than older, pulsatile LVADs (36). Aortic insufficiency most likely occurs due to commissural fusion of the AV leaflets from immobility with associated remodeling and/or trauma from highpressure continuous flow from the outflow cannula (37), resulting in a futile circuit from valvular insuf-

PROCEDURES FOR PATIENTS ON AN LVAD Because patients with LVADs live longer, more LVAD patients are requiring minor procedures and noncardiac surgery. These procedures should be coordinated with an LVAD specialist. Specific attention should be

given

to

the

perioperative

management

of

antithrombotic therapy and BP monitoring as the available data highlight an increased risk of bleeding, higher frequency of intraoperative hypotension, and a risk for acute kidney injury when these patients undergo noncardiac surgery (39,40). As mentioned previously, there

are multiple reasons for

the

increased risk of bleeding beyond the risks of antithrombotic therapy, and the risk may be underestimated by providers who are unfamiliar with LVADs. For example, in a study of patients who underwent noncardiac operations, including abdominal surgeries, thoracic surgeries, and endoscopic procedures at the Mayo Clinic, 15% of operations required red blood cell transfusions, 9% required fresh frozen plasma, and 6% required platelets (39).

CONCLUSIONS

ficiency that reduces LVAD efficiency and leads to HF symptoms. That is, blood travels from the LV through

The

the pump, into the aorta, back through the AV, and

increasing, as is their life expectancy. Non-LVAD

number

of

ambulatory

LVAD

patients

is

again into the LV. Due to the continuous nature of AV

specialists will increasingly encounter LVAD pa-

insufficiency, even a small regurgitant orifice can lead

tients and should be armed with the tools to provide

to a large volume of regurgitant blood flow. Aortic

initial assessment and management for these com-

insufficiency should be assessed by echocardiogra-

plex patients. Co-management of these patients will

phy; management typically involves BP control and

also become increasingly important as research and

evaluation for AV intervention (transcatheter or sur-

device innovations allow us to overcome the chal-

gical AV replacement or surgical oversewing).

lenges preventing expansion of LVAD therapy to more patients such as the high rate of adverse events, the care required for devices with external battery

UNRESPONSIVE PATIENTS AND

sources, and cost.

CARDIOPULMONARY RESUSCITATION

ACKNOWLEDGMENTS The

authors

thank

Erin

Care for an unresponsive LVAD patient requires unique

Campbell, MS, for editorial contributions and Jon-

considerations compared with the standard approach

athon Cook for assistance with images. Ms. Campbell

to advanced cardiovascular life support: 1) assessment

and Mr. Cook did not receive compensation for their

for normal LVAD power and function is essential

contributions. Ms. Campbell is an employee at the

(evaluate device connections, check device parame-

institution where this study was conducted.

ters and alarms, and auscultate for LVAD hum) (38); 2) assessment of pulse and BP is limited by continuous-

ADDRESS FOR CORRESPONDENCE: Dr. Adam D.

flow physiology; 3) there are limited data for the safety

DeVore, Department of Medicine, Duke Clinical Research

and efficacy of chest compressions in LVAD patients,

Institute, 400 Pratt Street, NP-8064, Durham, North

although

Carolina 27705. E-mail: [email protected].

device

manufacturers

caution

about

9

10

DeVore et al.

JACC: HEART FAILURE VOL.

-, NO. -, 2017 - 2017:-–-

Management of LVAD for the Non-LVAD Specialist

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KEY WORDS heart failure, left ventricular assist devices, mechanical circulatory support

29. Frontera JA, Starling R, Cho SM, et al. Risk factors, mortality, and timing of ischemic and

A PPE NDI X For supplemental figures, please see the online version of this article.