Download Continuous Flow Left ventricular Assist Device

Cardiovascular Innovations and Applications
Vol. 1 No. 1 (2015) 107–118
ISSN 2009-8618
DOI 10.15212/CVIA.2015.0013
Review
Continuous Flow Left Ventricular Assist Device
Therapy: A Focused Review on Optimal P
­ atient
Selection and Long-Term Follow-up Using
­Echocardiography
Juan R. Vilaro, MD1,2, Anita Szady, MD2, Mustafa M. Ahmed, MD2, Jacqueline Dawson, MD3
and Juan M. Aranda Jr., MD2
North Florida/South Georgia Veterans Health System, Cardiology Section, Gainesville, FL, USA
University of Florida College of Medicine, Division of Cardiovascular Medicine, Gainesville, FL, USA
3
Western Kentucky Heart and Lung Associates, Division of Cardiology, Scottsville, KY, USA
1
2
Abstract
Despite widespread awareness and use of scientifically proven life-prolonging medical and device-based therapies
over the last two decades, heart failure remains a leading cause of morbidity, mortality, and health care expenditure
in the United States. Mechanical circulatory support with a continuous-flow left ventricular assist device (CF-LVAD),
either as a bridge to heart transplantation or as destination therapy, is an increasingly used treatment modality for patients with advanced heart failure syndromes that worsen despite their receiving standard therapies. CF-LVAD support
creates unique hemodynamic alterations that must be understood to provide appropriate care for these patients before
and after implantation. Echocardiography is essential in the evaluation of patients who are being considered for or are
mechanically supported by CF-LVADs. Here we provide a focused clinical review on the use of echocardiography in
two main aspects of the evaluation of these patients: (a) optimal patient selection for CF-LVAD support and (b) followup assessment of optimal pump function.
Keywords: echocardiography; continuous-flow left ventricular assist device; heart failure; decision making;
­outcomes
Introduction
Despite widespread awareness and use of scientifically proven life-prolonging medical and
device-based therapies over the last two decades,
heart failure remains a leading cause of morbidity, mortality, and health care expenditure in the
Correspondence: Juan R. Vilaro, MD, 1600 SW Archer
Rd, Box 100277, Gainesville, FL 32610-0277, USA,
Tel.: +1 (352) 273-9075, Fax: +1 (352) 846-0314,
E-mail: [email protected]
© 2015 Cardiovascular Innovations and Applications
United States [1]. Patients who have progressive
heart failure syndromes despite receiving standard
treatment, including medical therapy and cardiac
resynchronization, are being increasingly considered for implantation of continuous-flow left
ventricular (LV) assist devices (CF-LVADs). CFLVADs are effective in improving survival and
quality of life in patients with advanced heart failure, and can be used as destination therapy or as a
bridge to heart transplantation [2, 3]. The increasing incidence of CF-LVAD implantation over the
last decade mandates an effort from all practicing physicians, not just heart failure specialists,
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to understand the basic anatomic and physiologic
implications of these devices on cardiac structure
and function. Echocardiography plays an integral
role in the evaluation of patients with advanced
heart failure who are being considered for or are
mechanically supported by a CF-LVAD. Here
we provide a focused clinical review on the use
of echocardiography in two main aspects of the
evaluation of these patients: (a) optimal patient
selection for CF-LVAD support and (b) follow-up
assessment of optimal pump function.
events prevent optimal function of the CF-LVAD
as they automatically trigger speed decrements
and are frequently associated with ventricular
arrhythmias [7]. From a structural and functional
standpoint, hearts with a severely reduced LV
ejection fraction and moderate to severe degrees of
LV dilation are therefore likeliest to benefit from
­CF-LVAD support.
Optimal Patient Selection
Assessment of RV function is critical in patients
being considered for LV assist device (LVAD)
implantation. The hemodynamic effects of a CFLVAD on the right ventricle can be divergent. The
desired favorable effect is improvement in RV performance following unloading of the left side of the
heart and subsequent decongestion of the pulmonary circulation. However, several hemodynamic
consequences on the right ventricle following initiation of CF-LVAD support challenge the right side
of the heart. Three potentially detrimental effects
on right-sided heart function are (1) acute increase
in right ventricular preload (which requires an
equivalent increase in right-sided cardiac output),
(2) leftward septal deformation resulting from LV
unloading leading to worsening RV function, and
(3) worsening tricuspid regurgitation.
There are numerous validated echocardiographic
measures of RV structure and function [8]. This
review will focus on two indices that have been
studied in CF-LVAD patients, are reproducible, and
are easily obtainable: (a) tricuspid annular plane systolic excursion (TAPSE) and (b) heart rate–­corrected
duration of tricuspid regurgitation (TRDc).
TAPSE represents the distance of longitudinal
motion of the tricuspid annulus during systole and
is a validated index of RV systolic function [8]. It is
obtained by M-mode imaging of the lateral tricuspid annulus obtained from an apical four-chamber
view. An example is illustrated in Figure 1. TAPSE
values below 7.5 mm have high specificity for
postoperative right-sided heart failure, and may
indicate a need for more aggressive preoperative
hemodynamic optimization and/or the need for
prolonged inotropic support following CF-LVAD
implantation [9].
In patients being considered for durable CF-LVAD
implantation, the preoperative echocardiogram is
a critical part of the evaluation and can be a powerful predictor of short-term and long-term clinical outcomes after implantation. The preoperative
echocardiogram should focus on the following:
• Detailed assessment of right ventricular (RV)
and LV size, structure, and function
• Presence of significant valvular regurgitation,
particularly of the aortic and tricuspid valves
• Presence of intracardiac thrombi
• Presence of intracardiac shunts
Left Ventricular Structure and
­Function
Patients being considered for CF-LVAD placement
almost invariably have severe reduction in their
LV systolic function. Consideration of mechanical
circulatory support, including CF-LVADs, is not
recommended if the LV ejection fraction is greater
than 25% [4]. Careful measurement of LV dimensions is also important, as the presence of relatively small LV cavities, specifically smaller than
63 mm, has been independently associated with
increased morbidity and mortality after CF-LVAD
implantation [5]. This is likely related to excessive
LV emptying and exaggerated leftward shift of
the interventricular septum due to its close proximity to the inflow cannula. This abnormal septal
deformation worsens RV function [6], and can also
cause direct physical contact of the septum with
the inflow cannula, termed a s­ uction event. Suction
Right Ventricular Structure
and Function
J.R. Vilaro et al., Continuous Flow LVAD Therapy: Echo Review
109
Aortic Regurgitation
Figure 1 Assessment of Right Ventricular Systolic
Function by Tricuspid Annular Plane Systolic Excursion (TAPSE) Measurement. The Longitudinal Motion of
the Lateral Tricuspid Annulus is 27 mm, Consistent with
­Normal Right Ventricular Systolic Function (Normal is
More Than 16 mm).
TRDc is a novel index described by Topilsky
et al. [5] in a large cohort of CF-LVAD patients
from the Mayo Clinic. One calculates it by measuring the duration of the tricuspid regurgitant Doppler jet and dividing it by the square root of the R-R
interval. TRDc is a heart rate–adjusted measure of
the time to pressure equalization between the right
ventricle and the right atrium during systole that
integrates right atrial compliance and the severity
of tricuspid regurgitation. In this regard, it can predict the hemodynamic impact of an acute volume
load increase on the right atrium, an expected result
of CF-LVAD implantation. Not surprisingly, it was
found on multivariate analysis to have a strong ability to predict rates of RV failure and death following
LVAD implantation. Patients with a TRDc of less
than 461 ms had an adjusted 2-year mortality odds
ratio of 2.3 compared with patients with a TRDc
longer than 461 ms. Examples of TRDc that would
predict low and high risks of RV failure and death
are illustrated in Figure 2.
Valvular Insufficiency
Accurate assessment of any underlying valvular
regurgitation, particularly of the aortic and tricuspid
valves, is crucial in the evaluation of patients being
considered for CF-LVADs, as it directly impacts
decisions to perform additional surgery at the time
of implantation.
There are several validated quantitative and qualitative methods for assessing the severity of aortic insufficiency (AI) [10]. Quantitative methods
include regurgitant orifice and regurgitant volume
calculation, which can be done with spectral Doppler imaging or the proximal isovelocity surface
area method, and vena contracta or jet width measurement. Qualitative measures include pressure
half-time and degree of descending aorta diastolic
flow reversal. A brief summary of quantitative
and qualitative estimates of AI severity is given in
Table 1. It is important to remember that in patients
with advanced heart failure, LV filling pressures are
almost invariably elevated and the pressure halftime method may overestimate the severity of AI
significantly [11]. The severity of any preexisting
AI will typically worsen to some degree following
initiation of CF-LVAD support [12]. Although CFLVAD support is in many cases well tolerated in
patients with minimal or mild AI, the presence of
moderate AI or worse can result in a physiologically
ineffective circuit (left ventricle → inflow cannula
→ outflow cannula → ascending aorta → left ventricle) owing to a large fraction of the blood volume
exiting the outflow graft regurgitating into the left
ventricle [13]. For this reason, any patient with AI
of more than mild severity should also undergo concomitant aortic valve closure at the time of LVAD
implantation. Repair with a single coaptation stitch
at the time of implantation provides effective and
durable repair of moderate or severe AI in patients
in whom a CF-LVAD has been implanted [14].
Tricuspid Regurgitation
A detailed assessment of tricuspid valve structure
and function is key in the preoperative assessment
of patients being considered for CF-LVAD implantation, particularly when there is any significant
degree of tricuspid regurgitation. Similarly to its
effects on overall RV function, the hemodynamic
effects of CF-LVAD support on tricuspid regurgitation may result in worsening, unchanged, or
improved tricuspid regurgitation severity [15, 16].
The acute increase in RV end-diastolic volumes
following CF-LVAD support can cause functional
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J.R. Vilaro et al., Continuous Flow LVAD Therapy: Echo Review
A
B
Figure 2 (A) Example of a Patient with a Heart Rate–corrected Tricuspid Regurgitation Duration (TRDc) Conferring a High
Risk of Postoperative Right-sided Heart Failure and Death (TRDc = 384 ms). (B) Example of a patient with a TRDc conferring
a low risk of right ventricular failure and death (TRDc = 519 ms).
Table 1 Echocardiographic Parameters Used in Grading the Severity of Aortic Regurgitation.
Parameter
Mild
Moderate
Severe
Vena contracta (cm)
Jet width (% of LVOT width)
Regurgitant volume (ml/beat)
EROA (cm2)
Descending aorta diastolic flow reversal
Pressure half-time (ms)
<0.3 cm
<25
<30
<0.1
Brief, early diastolic
>500
0.3–0.60
25–64
30–59
0.1–0.29
Intermediate
200–500
>0.6
>65
>60
>0.30
Holodiastolic
<200
EROA, effective regurgitant orifice area; LVOT, left ventricular outflow tract.
tricuspid regurgitation to worsen, leading to ineffective forward flow and a syndrome of progressive
RV failure. The severity of tricuspid ­regurgitation
at the baseline is associated with increased risk
of RV failure when it is moderate or worse on the
preoperative transthoracic echocardiogram [17].
J.R. Vilaro et al., Continuous Flow LVAD Therapy: Echo Review
A
111
B
Figure 3 (A) Example of severe tricuspid regurgitation by color Doppler imaging. Note the broad-based regurgitant jet reaching the posterior wall of the right atrium. (B) Pulsed-wave Doppler imaging demonstrating hepatic vein systolic flow reversal,
consistent with severe tricuspid regurgitation.
Table 2 Echocardiographic Parameters Used in Grading the Severity of Tricuspid Regurgitation.
Parameter
Mild
Moderate
Vena contracta (cm)
Jet area (cm)
Doppler profile
Hepatic vein flow Doppler
Not defined
<5
Soft, parabolic
Systolic dominant
Not defined, but <0.7
5–10
Dense, variable contour Systolic blunting
However, there are conflicting data regarding the
benefits of tricuspid valve repair at the time of CFLVAD implantation in patients with moderate or
severe tricuspid regurgitation, and the decision to
perform concomitant tricuspid valve repair is ultimately deferred to the performing surgeon [18–20].
Tricuspid regurgitation severity can be graded
quantitatively by vena contracta width or tricuspid
regurgitant jet area, or qualitatively by evaluation
of the Doppler profile of the hepatic vein (systolic
flow reversal implies severe tricuspid regurgitation)
[10]. An illustration of severe tricuspid regurgitation by color Doppler imaging as well as hepatic
vein systolic flow reversal is illustrated in Figure 3.
Table 2 briefly summarizes the parameters of tricuspid regurgitation severity.
Evaluation for Intracardiac Thrombi
Preoperative identification of intracardiac thrombus, particularly in the LV apex, which is not
uncommon with dilated cardiomyopathy and a
severely reduced LV ejection fraction, is also an
important part of preoperative planning before CF-
Severe
>0.7
>10
Dense, early peaking, triangular
Systolic flow reversal
LVAD ­implantation. Although the presence of an
apical thrombus does not contraindicate placement
of a CF-LVAD, it requires removal of the thrombus at the time of surgery before insertion of the
inflow cannula in the LV apex. One study reported
that of 100 patients in whom an LVAD has been
implanted over 3 years, six had an LV apical thrombus identified preoperatively or intraoperatively.
None of them experienced a neurological event,
pump thrombosis, or pump malfunction [21]. LV
thrombi can be readily detected by transthoracic
echocardiography, typically in the apical views. If
images are of limited quality, echocardiography
contrast agents should be used as they significantly
improve the sensitivity, specificity, and accuracy of
echocardiography in diagnosing LV thrombus [22].
An example is shown in Figure 4.
Presence of Intracardiac Shunts and
Patent Foramen Ovale
The echocardiogram before CF-LVAD implantation
should include careful inspection for any evidence
of intracardiac shunting, including a patent foramen
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J.R. Vilaro et al., Continuous Flow LVAD Therapy: Echo Review
be closed at the time of surgery to eliminate the risk
of hypoxemia from right to left shunting.
Follow-up Echocardiographic
Assessment After ContinuousFlow Left Ventricular Assist
Device Placement
After surgical implantation of a CF-LVAD, echocardiography continues to be an essential clinical
tool for the ongoing evaluation and follow-up of
pump function, native cardiac function, and overall patient care. The key elements of an echocardiogram in the patient supported with a CF-LVAD
should focus on the following:
Figure 4 Apical Four-Chamber View Demonstrating Mural
Left Ventricular Apical Thrombus in a Patient with Recent
Anterior Transmural Myocardial Infarction.
ovale (PFO). A PFO are not uncommon and has a
reported prevalence of up to 25% in the general population [23]. Although it is typically noted incidentally and not felt to cause any significant shunting,
the acute lowering of left-sided intracardiac pressures resulting from CF-LVAD support can precipitate increased right to left interatrial shunting and
clinically important hypoxemia and cyanosis [24].
Preoperatively, transthoracic echocardiography can
identify atrial level communication with color Doppler imaging of the interatrial septum, or in the apical windows following intravenous administration
of agitated saline [25]. The appearance of agitated
saline bubbles in the left heart chambers within three
beats or less of their appearance in the right side of
the heart is typically felt to represent the presence
of an intracardiac shunt, most commonly a PFO. It
is, however, important to remember that in patients
with advanced heart failure and significantly elevated right-and left-sided atrial pressures there may
not be a high enough gradient between both atria to
cause a detectable shunt. Therefore, in addition to
preoperative inspection for shunting, the intraoperative transesophageal echocardiogram should be used
to confirm the presence or absence of any shunting,
including a PFO that may not have been detected by
transthoracic echocardiography. A PFO identified in
patients undergoing CF-LVAD implantation should
• Evaluation of adequate LV unloading:
• Frequency of aortic valve opening
• LV dimension and interventricular septal
morphology
• Inflow and outflow cannula velocities
• Detailed assessment of RV function, including
serial assessment over time
Evaluating Adequate Left Ventricular
Unloading in Patients Supported by
a Continuous-Flow Left Ventricular
Assist Device
There are multiple features of the echocardiogram
that can provide evidence of adequate LV unloading,
which is invariably the primary hemodynamic goal
of CF-LVAD support. These include the degree and
frequency of aortic valve opening, the change in LV
dimensions over time, and the cannula velocities.
Aortic Valve Opening
Evaluation of aortic valve opening by echocardio­
graphy is a simple, reliable way of determining adequate LV unloading in patients following CF-LVAD
implantation [26]. In patients with CF-LVAD support, the aortic valve typically should open not
every beat, but rather intermittently every two to
three beats, or not at all. The frequency of aortic
valve opening can be assessed by 2D imaging in the
parasternal long-axis and short-axis views, as well
J.R. Vilaro et al., Continuous Flow LVAD Therapy: Echo Review
as the apical three-chamber view. However, postsurgically image quality is frequently limited, and
M-mode imaging through the aortic valve plane can
assess the degree of leaflet opening and excursion
more definitively (Figure 5). An aortic valve that
opens consistently with each systole suggests that
the left ventricle is not adequately unloaded and LV
pressures remain significantly elevated. Common
causes of inadequate LV unloading include uncontrolled hypertension, intravascular hypervolemia,
any form of mechanical obstruction in the pump,
113
including thrombus or kinking of the outflow graft,
and the speed setting being too low. Table 3 summarizes the different clinical features of the most
common causes of poor LV unloading.
Septal Morphology and Ventricular
Dimensions
Follow-up echocardiographic assessment of LV
chamber dimensions, together with the morphology
Figure 5 M-mode Image of the Aortic Valve from Patient with Continuous-flow Left Ventricular Assist Device Support.
Note the minimal aortic leaflet excursion indicative of adequate unloading of the left ventricle.
Table 3 Causes of Poor Left Ventricular Unloading While the Patient has Continuous-flow Left Ventricular Assist Device
­Support.
Condition
Clinical features
Management
Uncontrolled
hypertension
Hypervolemia
Elevated PI/power, high RTF, may have persistent/
worsening symptoms of left-sided heart failure
Elevated PI/power, JVD, peripheral edema, may
have persistent/worsening symptoms of left-sided
heart failure
Persistent/worsening symptoms of left-sided heart
failure, evidence of hemolysis is common (urine
discoloration, increased LDH concentration) if
secondary to thrombosis
Persistent/worsening symptoms of left-sided heart
failure
Increase vasodilator therapy
Mechanical
obstruction
Pump speed
too low
Intensify diuresis
CT angiography to evaluate the patient for the
site of obstruction; if thrombus is suspected,
intensify anticoagulation; urine alkalinization;
pump exchange may be indicated
Increase pump speed, ideally under
echocardiographic guidance
CT, computed tomography; JVD, jugular venous distention; LDH, lactate dehydrogenase; PI, pulsatility index;
RTF, return to flow.
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and shape of the interventricular septum, can also
provide information regarding the adequacy of LV
unloading. Following initiation of CF-LVAD support, LV dimensions typically decrease and slight
leftward motion of the interventricular septum
is expected, reflecting a moderate decrease in LV
pressures relative to RV pressures [27]. If, however,
there is an interval increase of the LV dimension, or
if there is a predominantly rightward motion of the
septum, this suggests increased LV pressure relative
to RV pressure, and is typically a sign of inadequate
LV unloading. The differential is similar to that of
an aortic valve that opens constantly, and workup
for all of the previously mentioned scenarios should
be pursued (Table 3).
Conversely, if the leftward septal shift is pronounced or associated with a dramatic reduction in
LV cavity size, this highly suggests excessive LV
decompression by the pump. Common causes of
this include the pump speed being too high, significant recovery of LV systolic function, or any scenario of reduced LV preload, including intravascular hypovolemia or right-sided heart failure. Table 4
summarizes a diagnostic approach to help distinguish between these different scenarios, as well as
potential therapeutic options.
A ramp study should be considered whenever
there is clinical evidence of poor LV unloading due
to suspected mechanical obstruction [28]. This consists in measuring echocardiographic LV dimensions
and the frequency of aortic valve opening while
serially increasing the CF-LVAD pump speed. An
inability to decrease LV dimensions or reduce the
frequency of aortic valve opening despite increasing pump speeds should raise concern for mechanical obstruction in the pump, including pump thrombosis.
Cannula Velocities
The echocardiogram in patients supported with CFLVADs should include attempts to measure blood
flow velocities through the inflow cannula and
outflow graft. However, Doppler measurements of
inflow and outflow velocities are rarely interpretable in centrifugal-flow CF-LVADs because of
multiple artifacts [29]. In axial-flow LVADs, inflow
velocities are best evaluated in the apical windows,
where flow is most parallel to the ultrasound beam.
Outflow graft velocities can be measured in the
parasternal long-axis window or the suprasternal
window as blood flows out of the pump into the
ascending aorta. There is no consensus on what the
normal range of cannula or graft velocities should
be. Ideally, there should be laminar flow by color
Doppler imaging, with minimal turbulence, which
suggests adequate alignment with mitral inflow. By
spectral Doppler imaging, velocities vary widely
depending on the patient and loading conditions,
typically ranging between 0.3 and 1.5 m/s [30].
Most patients have some degree of phasic variation
Table 4 Causes of Excessive Left Ventricular Decompression.
Condition
Clinical features
Management
Pump speed
too high
Hypovolemia
Frequent PI/suction events, low flow alarms,
ventricular arrhythmias
Frequent PI/suction events, ventricular
arrhythmias, dry skin turgor, flat JVP, low RTF,
preserved right ventricular function
JVD, peripheral edema, ascites with frequent
PI/suction events, low flow alarms, ventricular
arrhythmias, significant RV dilation/
hypokinesis, worsening tricuspid regurgitation
Frequent PI/suction events, PI and flow values
may vary, improved LVEF by echocardiography
Reduce pump speed, ideally under
echocardiographic guidance
Stop/reduce use of diuretics, encourage fluid
intake, IV fluids if severe
Right-sided
heart failure
Recovery of
LV function
Intensify use of diuretics, consider inotropes,
speed reduction can be considered, if listed
for transplant and meets criteria for status 1A
Consider weaning patient off CF-LVAD
support (over weeks to months). If tolerated
can consider explantation
CF-LVAD, continuous-flow left ventricular assist device; IV, intravenous; JVD, jugular venous distention; JVP, jugular venous
pressure; LV, left ventricular; LVEF, left ventricular ejection fraction; PI, pulsatility index; RTF, return to flow;
RV, right ventricular.
J.R. Vilaro et al., Continuous Flow LVAD Therapy: Echo Review
in ­velocity over the cardiac cycle, which reflects
changes in flow through the pump due to native
ventricular contraction and diastolic mitral inflow
(Figure 6). Although there is not an established
normal range of inflow cannula or outflow graft
velocities, any significant change in these velocities over time warrants further evaluation and
should be interpreted in the clinical context of the
individual patient.
Assessment of Right Ventricular
Function
As discussed previously, it is crucial for patients
­supported by CF-LVADs to have relatively ­preserved
RV function in order to maintain adequate rightsided cardiac output. Syndromes of right-sided
heart failure can occur acutely in the early postoperative period or can have a more chronic presentation several years after implantation [31, 32]. Any
interval worsening of RV dilation or the previously
described indices of RV function support the diagnosis of RV failure after CF-LVAD implantation in
the appropriate clinical context. In addition, echocardiography also provides a simple noninvasive
way of detecting hemodynamics suggestive of RV
decompensation.
115
Patients with right-sided heart failure after ventricular assist device (VAD) implantation typically
experience a syndrome of RV volume overload as
the right side of the heart struggles to match the
effective forward flow provided by a CF-LVAD.
As this progresses, the right ventricle becomes
progressively dilated, functional tricuspid regurgitation worsens, and right-sided filling pressures
become severely elevated. The echocardiographic
estimation of right atrial and RV systolic pressure
using the inferior vena cava diameter and tricuspid
regurgitant jet velocity are well validated [8]. These
methods appear to retain their accuracy in patients
following CF-LVAD implantation [33]. Significant
dilation of the inferior vena cava with minimal or no
inspiratory collapse together with a relatively low
tricuspid regurgitant jet velocity (less than 2.5 m/s
in the setting of a dilated inferior vena cava) is the
echocardiographic correlate of RV failure diagnosed by invasive hemodynamics, and highly suggests post–VAD implantation right-sided heart failure. The onset of RV failure after VAD implantation
portends a poor prognosis and increased mortality.
Treatment options are limited unless patients are
candidates for heart transplantation or biventricular
support [31]. Symptomatically, patients benefit from
intravenous diuretics and initiation of inotropes for
RV support. If septal morphology and ventricular
Figure 6 Inflow Cannula Velocity Measured from an Off-axis Apical Three-chamber View from a Patient with a Normally
Functioning Continuous-flow Left Ventricular Assist Device.
Note the relatively low velocities, 30–80 cm/s, with phasic variation throughout the cardiac cycle reflecting some degree of
native pulsatile flow.
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J.R. Vilaro et al., Continuous Flow LVAD Therapy: Echo Review
A
B
Figure 7 Tricuspid Regurgitation Doppler and Inferior Vena Cava M-mode Imaging from a Patient with Severe Right Ventricular Failure Following Continuous-flow Left Ventricular Assist Device Placement.
Note the combination of the low velocity of tricuspid regurgitation (A) and a severely dilated inferior vena cava with absence
of inspiratory collapse (B), consistent with high right atrial pressure and low right ventricular contractile function.
chamber dimensions suggest excessive LV emptying and severe asymmetric dilation of the right
ventricle relative to the left ventricle, a decrease in
pump speed can also be helpful. Figure 7 illustrates
images from a patient with post–VAD implantation
right-sided heart failure.
Conclusion and Take-Home Message
The incidence of advanced heart failure patients who
are potential candidates for mechanical ­support with
CF-LVADs is steadily increasing worldwide. Echocardiography is a simple, noninvasive, yet highly
useful diagnostic imaging modality that provides
easily interpretable information that is instrumental
in the care of patients supported by this relatively
complex technology. It is crucial to remember that
the utility of echocardiography is best when the
images are understood in the clinical context of
each individual patient, and decisions should never
be made solely on the basis of the results of a single
study.
J.R. Vilaro et al., Continuous Flow LVAD Therapy: Echo Review
117
Conflict of Interest
Funding
The authors declare no conflict of interest.
This research received no specific grant from any
funding agency in the public, commercial or notfor-profit sectors.
References
1.
Fonarow
GC,
Yancy
CW,
Hernandez AF, Peterson ED,
­
­Spertus JA, Heidenreich PA. Potential impact of optimal implementation of evidence-based heart failure
therapies on mortality. Am Heart J
2011;161:1024–30.e1023.
2.
Christiansen
S,
Brose
S,
Autschbach R. [Surgical therapy
­
of end-stage heart failure]. Herz
2003;28:380–92.
3. Miller LW, Pagani FD, Russell
SD, John R, Boyle AJ, Aaronson
KD, et al. Use of a continuousflow device in patients awaiting
heart transplantation. N Engl J Med
2007;357:885–96.
4. Yancy CW, Jessup M, Bozkurt B,
Butler J, Casey DE, Drazner MH,
et al. 2013 ACCF/AHA guideline
for the management of heart failure: a report of the American College of Cardiology Foundation/
American Heart Association Task
Force on Practice Guidelines. J Am
Coll Cardiol 2013;62:e147–239.
5. Topilsky Y, Oh JK, Shah DK,
­Boilson BA, Schirger JA, Kushwaha
SS, et al. Echocardiographic predictors of adverse outcomes after continuous left ventricular assist device
implantation. JACC Cardiovasc
Imaging 2011;4:211–22.
6. Neragi-Miandoab S, Goldstein D,
Bello R, Michler R, D’Alessandro
D. Right ventricular dysfunction
following continuous flow left ventricular assist device placement in 51
patients: predicators and outcomes.
J Cardiothorac Surg 2012;7:60.
7.Vollkron M, Voitl P, Ta J,
Wieselthaler G, Schima H. Suction events during left ventricular
support and ventricular arrhythmias. J Heart Lung Transplant
2007;26:819–25.
8. Rudski LG, Lai WW, Afilalo J,
Hua L, Handschumacher MD,
­Chandrasekaran K, et al. Guidelines
for the echocardiographic assessment of the right heart in adults: a
report from the American Society
of Echocardiography endorsed by
the European Association of Echocardiography, a registered branch
of the European Society of Cardiology, and the Canadian Society
of Echocardiography. J Am Soc
Echocardiogr 2010;23:685–713;
quiz 786-688.
9. Puwanant S, Hamilton KK, Klodell
CT, Hill JA, Schofield RS, Cleeton
TS, et al. Tricuspid annular motion
as a predictor of severe right ventricular failure after left ventricular
assist device implantation. J Heart
Lung Transplant 2008;27:1102–7.
10.Zoghbi WA, Enriquez-Sarano M,
Foster E, Grayburn PA, Kraft CD,
Levine RA, et al. Recommendations for evaluation of the severity of native valvular regurgitation
with two-dimensional and Doppler echocardiography. J Am Soc
Echocardiogr 2003;16:777–802.
11.Griffin BP, Flachskampf FA, Siu
S, Weyman AE, Thomas JD. The
effects of regurgitant orifice size,
chamber compliance, and systemic vascular resistance on aortic regurgitant velocity slope and
pressure half-time. Am Heart J
1991;122:1049–56.
12.Topilsky Y, Oh JK, Atchison FW,
Shah DK, Bichara VM, Schirger
JA, et al. Echocardiographic findings in stable outpatients with
properly functioning HeartMate II
left ventricular assist devices. J Am
Soc Echocardiogr 2011;24:157–69.
13.Gregory SD, Stevens MC, Wu E,
Fraser JF, Timms D. In vitro evalu-
ation of aortic insufficiency with a
rotary left ventricular assist device.
Artif Organs 2013;37:802–9.
14.McKellar SH, Deo S, Daly RC,
Durham LA, Joyce LD, Stulak JM,
et al. Durability of central aortic
valve closure in patients with continuous flow left ventricular assist
devices. J Thorac Cardiovasc Surg
2014;147:344–8.
15.Atluri P, Fairman AS, ­MacArthur
JW, Goldstone AB, Cohen JE,
Howard JL, et al. Continuous
flow left ventricular assist device
implant significantly improves
­pulmonary hypertension, right ventricular contractility, and tricuspid
valve competence. J Card Surg
2013;28:770–5.
16.Piacentino V, Williams ML, Depp
T, Garcia-Huerta K, Blue L, Lodge
AJ, et al. Impact of tricuspid valve
regurgitation in patients treated
with implantable left ventricular
assist devices. Ann Thorac Surg
2011;91:1342–6; discussion 1346–7.
17. Potapov EV, Stepanenko A, ­Dandel
M, Kukucka M, Lehmkuhl HB,
Weng Y, et al. Tricuspid incompetence and geometry of the right
ventricle as predictors of right
ventricular function after implantation of a left ventricular assist
device. J Heart Lung Transplant
2008;27:1275–81.
18.Piacentino V, Ganapathi AM,
Stafford-Smith M, Hsieh MK,
­
Patel CB, Simeone AA, et al. Utility of concomitant tricuspid valve
procedures for patients undergoing
implantation of a continuous-flow
left ventricular device. J Thorac Cardiovasc Surg 2012;144:1217–21.
19. Maltais
S,
Topi­lsky
Y,
­Tchantchaleishvili V, McKellar
SH, Durham LA, Joyce LD, et al.
118
J.R. Vilaro et al., Continuous Flow LVAD Therapy: Echo Review
Surgical treatment of tricuspid
valve insufficiency promotes early
reverse remodeling in patients with
axial-flow left ventricular assist
devices. J Thorac Cardiovasc Surg
2012;143:1370–6.
20.
Robertson JO, Grau-Sepulveda
MV, Okada S, O’Brien SM,
­Matthew Brennan J, Shah AS, et al.
Concomitant tricuspid valve surgery during implantation of continuous-flow left ventricular assist
devices: a Society of Thoracic Surgeons database analysis. J Heart
Lung Transplant 2014;33:609–17.
21.Engin C, Yagdi T, Balcioglu O,
Erkul S, Baysal B, Oguz E, et al. Left
ventricular assist device implantation in heart failure patients with
a left ventricular thrombus. Transplant Proc 2013;45:1017–9.
22.Thanigaraj S, Schechtman KB,
Pérez JE. Improved echocardiographic delineation of left ventricular thrombus with the use of intravenous second-generation contrast
image enhancement. J Am Soc
Echocardiogr 1999;12:1022–6.
23.
Meissner
I,
Whisnant
JP,
Khandheria BK, Spittell PC,
­
O’Fallon WM, Pascoe RD, et al.
Prevalence of potential risk factors
for stroke assessed by transesophageal echocardiography and carotid
ultrasonography: the SPARC study.
Stroke Prevention: Assessment of
Risk in a Community. Mayo Clin
Proc 1999;74:862–9.
24.Srinivas CV, Collins N, Borger
MA, Horlick E, Murphy PM.
Hypoxemia complicating LVAD
insertion: novel application of the
Amplatzer PFO occlusion device. J
Card Surg 2007;22:156–8.
25. Marriott K, Manins V, Forshaw A,
Wright J, Pascoe R. Detection of
right-to-left atrial communication
using agitated saline contrast imaging: experience with 1162 patients
and recommendations for echocardiography. J Am Soc Echocardiogr
2013;26:96–102.
26. Estep JD, Stainback RF, Little SH,
Torre G, Zoghbi WA. The role of
echocardiography and other imaging
modalities in patients with left ventricular assist devices. JACC Cardiovasc Imaging 2010;3:1049–64.
27.Liao KK, Miller L, Toher C,
Ormaza S, Herrington CS, Bittner
HB, et al. Timing of transesophageal echocardiography in diagnosing patent foramen ovale in patients
supported with left ventricular
assist device. Ann Thorac Surg
2003;75:1624–6.
28.Uriel N, Morrison KA, Garan
AR, Kato TS, Yuzefpolskaya M,
Latif F, et al. Development of a
novel echocardiography ramp
test for speed optimization and
diagnosis of device thrombosis
in continuous-flow left ventricular assist devices: the Columbia
Ramp Study. J Am Coll Cardiol
2012;60:1764–75.
29.Shah NR, Cevik C, Hernandez A,
Gregoric ID, Frazier OH, ­Stainback
RF. Transthoracic echocardio­
graphy of the HeartWare left ventricular assist device. J Card Fail
2012;18:745–8.
30.Topilsky Y, Maltais S, Oh JK,
­Atchison FW, Perrault LP, ­Carrier
M, et al. Focused review on transthoracic echocardiographic assessment
of patients with continuous axial
left ventricular assist devices. Cardiol Res Pract 2011;2011:187434.
31. Kormos RL, Teuteberg JJ, Pagani
FD, Russell SD, John R, Miller
LW, et al. Right ventricular failure
in patients with the HeartMate II
continuous-flow left v­entricular
assist device: incidence, risk factors, and effect on outcomes. J
Thorac Cardiovasc Surg 2010;139:
1316–24.
32. Takeda K, Takayama H, Colombo
PC, Jorde UP, Yuzefpolskaya M,
Fukuhara S, et al. Late right heart
failure during support with continuous-flow left ventricular assist
devices adversely affects posttransplant outcome. J Heart Lung
Transplant 2015;34:667–74.
33.Estep JD, Vivo RP, Krim SR,
Cordero-Reyes AM, Elias B,
Loebe M, et al. Echocardiographic
Evaluation of Hemodynamics in
Patients With Systolic Heart Failure Supported by a ContinuousFlow LVAD. J Am Coll Cardiol
2014;64:1231–41.