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Ambulatory Inotropes in Severe Heart Failure
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From
American Heart Journal
Continuous Home Ambulatory Intravenous
Inotropic Drug Therapy in Severe Heart
Failure: Safety and Cost Efficacy
Authors: Andrew P. Sindone, BMed (Rons), FRACP, Anne M. Keogh, MD, FRACP, Peter S.
Macdonald, PhD, FRACP, Cate J. McCosker, RN, BA, and Annemarie F. Kaan, RN, CTCNC,
From the Heart and Lung Transplant Unit, St. Vincent's Hospital, Sydney, Australia
O Abstract
Some patients with dilated cardiomyopathy who are inotrope
dependent but remain well by undergoing infusions can be
managed by ambulatory infusions at home. We report our results
in 20 patients awaiting heart transplantation, unable to be
weaned from intravenous inotropic therapy on 2 or more
occasions, but who were well while receiving inotropes and
received home ambulatory infusions. The patients were treated
with ACE inhibitors, digoxin. diuretics, vasodilators, close
electrolyte management, and low-dose amiodarone for those
with more than four-beat ventricular tachycardia. Infusions were
delivered by a tunneled subclavian catheter and syringe driver.
Thirteen patients received dopamine, four received dobutamine,
and three received both. Mean duration of inotropic therapy was
5 months with 70% of the time spent as an outpatient. Eleven
patients received transplants, two remain on the waiting list, and
seven died after being removed from the list because of general
deterioration or renal dysfunction. There were no sudden deaths.
Actuarial survival was 71% at 3 months, which is not less than
that expected for an inotrope-dependent population. All patients
with idiopathic dilated cardiomyopathy survived to
transplantation. In contrast, all three with right heart failure
caused by pulmonary vascular disease and four of seven with
ischemic cardiomyopathy died. Inpatient days were reduced by
70%, leading to considerable cost savings. Home ambulatory
inotropic therapy is safe, cost-effective, best suited to those with
idiopathic dilated cardiomyopathy, and dramatically reduces
inpatient hospital duration. [Am Heart J 134(5):889-900, 1998.
© 1997 Mosby-Year Book, Inc.]
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Contents
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Abstract
Introduction
Methods
Results
Discussion
References
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Ambulatory Inotropes in Severe Heart Failure
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Heart failure is an incapacitating and increasingly common cause
of cardiac morbidity and mortality.[1'3] Inotrope infusions can
improve the hemodynamic and symptomatic condition of
patients with severe heart failure.[4'9] Of those patients awaiting
cardiac transplantation in Australia, 8% depend on inotropic
drug therapy at the time of transplantation, t10] Some of these
patients cannot be weaned from inotropic therapy without
hemodynamic compromise yet remain relatively well while
therapy is maintained.[10] Because of the shortage of donor
organs, these patients spend extended periods in the hospital,
occupying valuable hospital beds at high cost.[10] Administration
of home inotropic infusions on an ambulatory basis can create
patient independence and satisfactory quality of life while
maintaining optimal hemodynamic stability and reducing
hospital bed occupancy and health resource use while patients
await heart transplantation.[1M8]
Use of long-term inotropic therapy is still viewed by many
physicians as being associated with development of tolerance
and increased mortality rate.[4'9>19"22] There are few reported
experiences of continuous administration of ambulatory
inotropic therapy. However, more contemporary literature gives
support to the notion that long-term inotropic therapy can be
usedsafelyJ11'18'23'24!
This report reviews our experience with home ambulatory
inotropic infusions in an attempt to assess the cost benefits of
such treatment and to identify which subgroups derive the most
clinical benefit.
Patient inclusion criteria
Twenty patients with New York Heart Association functional
class IV heart failure received home ambulatory inotropic
infusions (dopamine or dobutamine) between 1990 and 1995.
Seventeen patients were actively listed for heart transplantation,
and two of three patients with pulmonary vascular disease were
listed for heart-lung transplantation. All patients were unable to
be weaned from inotropic therapy on two or more occasions yet
were stable receiving inotropic therapy and fit enough to manage
at home. No patient had significant aortic stenosis or active
angina pectoris. Inotropes were introduced in the hospital with
electrical monitoring. Having decided on home ambulatory
inotropic therapy, the infusions were administered continuously
without attempt to wean the infusion (except in one case).
Choice of inotrope was at the discretion of the treating physician.
Right heart catheterization was performed before the
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commencement of inotropic therapy to establish baseline
hemodynamic status and was repeated within 1 month or sooner,
if clinically indicated.
Concomitant management All patients were on maximum
tolerated standard oral heart failure therapy (Table I).
Electrolytes were monitored regularly with the serum potassium
being maintained >4.0 mmol/L and magnesium >0.95 mmol/L.
No patients had implantable cardioverter defibrillators or
permanent pacemakers. Low dose amiodarone was instituted if
there was more than four-beat ventricular tachycardia at > 120
beats/min while receiving inotropic therapy.[25'29] Amiodarone
200 mg three times a day for 7 days was followed by 200 mg
twice a day for 7 days, then 200 mg daily maintenance therapy.
Patients were monitored for a minimum of 4 days after starting
amiodarone.[30'31J
Inotropic drug preparation and stability
Dopamine 800 mg or dobutamine 800 to 1000 mg was dissolved
in 100 ml of 5% dextrose after withdrawal of an equivalent
amount of 5% dextrose (making an almost "neat" solution); the
100 ml bag of stock solution was stored for up to 24 hours. The
infusion rate was set at 6 to 8 mm/hr. The 20 ml syringe of the
pump was reloaded by the patient every 6 to 8 hours. Average
dopamine dosage was 4.4 +/- 1.1 mcg/kg/min and dobutamine
5.9 +/- 2.8 mcg/kg/min.
Stability data exist for concentrations of dopamine up to 320
mg/100 ml of 5% dextrose.[32] At this concentration, only 5% of
activity was lost after 14 days at 5° C when protected from light.
Other studies have demonstrated that a concentration of 80
mg/100 ml is stable for up to 7 days at 5° CJ33'34^ There is no
solubility data for the concentration of dopamine 800 mg/100 ml
of 5% dextrose used in our study. There was, however, no
detectable drug precipitation at our higher dosage, even when
dopamine and dobutamine were combined.
Concentrations of dobutamine up to 800 mg/100 ml of 5%
dextrose may demonstrate a pale pink discoloration and a 4%
loss of dobutamine in 24 hours when exposed to light.[351 There
are no data for the concentration of 1000 mg/100 ml of 5%
dextrose used in our outpatient group, but again, no detectable
precipitation occurred.
Dopamine and dobutamine infusions are compatible in the same
syringe driver delivery system for 24 hours. Doses previously
studied include 100 mg of dobutamine combined with 160 mg of
dopamine dissolved in 100 ml of 5% dextrose[36'37] and also 172
mg of dobutamine combined with 550 mg of dopamine dissolved
in 100 ml of 5% dextroseJ38]
Technique
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Ambulatory Inotropes in Severe Heart Failure
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Administration was by a tunneled subclavian silastic catheter.
This technique enables safe insertion under local anesthesia,
even in patients who are fully anticoagulated. The soft 18F
silastic Vygon catheter (Vygon Corp, East Rutherford, NJ) is
flexible and comfortable with little skin trauma and is well
tolerated by the patients. The venous catheter was only changed
if a clinical problem arose to preserve central venous access
sites.
The syringe driver
Drug administration was by a 20 ml syringe mounted on a
Graseby medical syringe driver (model MS16A, Graseby
Medical Limited; Herts, United Kingdom) (Fig. 1), which was
set at 6 to 8 mm/hr. It is small, portable, simple to operate, and
weighs 280 gm when the infusion and battery are loaded. The
battery must be changed twice a week. Each syringe driver was
used on multiple occasions over many years. One pump costs
approximately $1850. It is accurate over an 8-hour infusion
period to within 20 minutes (4.2%) of the prescribed infusion
time (in-house quality control).
Figure 1. (click here to zoom) Patient loading
syringe pump into syringe driver.
Patient education
During the inpatient period, patients were instructed in aseptic
care of the central access site and line, daily inspection of the
intravenous site for signs of infection, loading of infusions and
use of the syringe driver (Fig. 2). Infusions were conducted
without home nursing supervision. Patients attended the
outpatient clinic weekly for review. The patients and their
families were encouraged to undertake dressing changes while in
hospital under supervision to gain confidence and proficiency
(Table II).
Figure 2. (click here to zoom) Syringe pump
connected to tunneled subclavion Vygon catheter.
Statistics
Inpatient and outpatient duration were calculated from the date
of insertion of the subcutaneous tunneled subclavian Vygon
catheter. All data are expressed as the mean +/- SD. Where
changes from baseline were normally distributed, t tests were
used to compare treatment groups. Nonparametrically distributed
changes were analyzed with the Wilcoxon rank-sum test. Results
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Ambulatory Inotropes in Severe Heart Failure
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were considered significant when/? < 0.05.
O Results
Table I lists baseline demographic, hemodynamic, and
biochemical characteristics of the patients. Thirty percent of the
patients were in chronic atrial fibrillation. There were no
significant differences in baseline data between groups according
to underlying disease process (apart from those with right
ventricular failure having a higher left ventricular ejection
fraction,/? < 0.03) or according to which inotrope was
administered. However, the patients with ischemic
cardiomyopathy were significantly older than the other
diagnostic groups (p < 0.04 vs patients with idiopathic
cardiomyopathy; p < 0.04 vs patients with right heart failure)
(XableJE).
Concomitant medical therapy did not significantly differ
between groups at baseline, nor did it significantly change over
the course of the inotropic drug treatment. Fifty percent of
patients received low-dose amiodarone on a medium to longterm basis. No abnormalities of thyroid function occurred during
low-dose amiodarone administration in this patient group.
Thirteen patients received dopamine (mean 4.4 +/- 1.1
mcg/kg/min, range 2.5 to 7 mcg/kg/min), four patients received
dobutamine (mean 5.9 +/- 2.8 mcg/kg/min, range 4 to 10
mcg/kg/min), and three patients received both drugs (mean
dopamine dosage 3.7 +/- 1.1 mcg/kg/min, range 3 to 5
mcg/kg/min; mean dobutamine dosage 5.3 +/- 0.6 mcg/kg/min,
range 5 to 6 mcg/kg/min).
Right heart catheterization after 1 week of therapy demonstrated
stability of hemodynamics. Serum creatinine, albumin, and
protein concentrations remained stable but there was a
significant improvement in serum gamma glutamyl
transpeptidase levels (p < 0.02) (Table III).
Patient outcomes
Of the 20 patients, 11 underwent transplantation, two remained
on the waiting list, and seven died (Table: III). Of the two on the
waiting list, one continues to receive home inotropic drug
therapy and one was weaned from dobutamine after 43 days and
remains in New York Heart Association class III 18 months after
cessation of the infusion. Nine (82%) of the 11 patients who
received transplantation survived to leave the hospital. Actuarial
survival for the entire group was 71% at 3 months (Fig. 3).
Figure 3. (click here to zoom) Cumulative survival
curve for the 20 patients who received intravenous
home ambulatory inotropic therapy.
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Mean duration of inotropic therapy was 150 +/-163 days per
patient (range 4 days to 17.5 months). Seventy percent of the
time receiving inotropic therapy (mean 104 days per patient) was
spent as an outpatient (Table III).
The 11 patients who underwent transplantation and two still
awaiting transplantation received inotropic support for 96 +/- 99
days per patient (range 4 days to 8.2 months). Sixty-seven
percent of the time receiving inotropic therapy (mean 64 days
per patient) was spent as an outpatient (Table III).
The seven patients who died were supported for a significantly
longer period (251 +/- 216 days per patient, range 24 days to
17.5 months;/? < 0.04) compared with those who underwent
transplantation or who were still waiting. Seventy-one percent of
the time receiving inotropic therapy was spent as an outpatient
(mean 6 months per patient). These seven patients died after
being removed from the list because of deterioration in general
state (n = 5) or irreversible renal dysfunction (n = 2). There were
no sudden deaths, but rather a gradual decline in clinical state
with increasing frequency of hospital readmissions and
consistent patient unwillingness in all cases to consider cessation
of inotropic therapy.
Patient symptoms
Nineteen of the 20 patients symptomatically improved. All 20
patients were initially in New York Heart Association functional
class IV. This status improved to 2.5 +/- 0.8 after a mean of 1
month of inotropic therapy. Four patients were fit enough while
receiving inotropic therapy to participate in a structured
gymnasium exercise program to reduce muscular
deconditioning, and 3 patients returned to their former
employment or education.
Outcome according to underlying disease
The six patients with idiopathic dilated cardiomyopathy spent a
mean of 122 +/- 124 days per patient as outpatients (78% of time
receiving inotropic therapy). All patients survived to
transplantation. The nine patients with ischemic cardiomyopathy
spent 58 +/- 102 days per patient as outpatients (54% of the time
receiving inotropic therapy); four of these seven patients died,
one from renal failure and three from general deterioration. None
was considered suitable for mechanical support. All four of the
patients who died were considered borderline candidates for
transplantation at the time of listing. The three patients with right
ventricular heart failure spent 290 +/- 247 days per patient as
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outpatients (85% of the time receiving inotropic therapy) with all
three patients ultimately dying from progressive right ventricular
failure. One of these three patients was not considered suitable
for heart-lung transplantation at the commencement of the
ambulatory inotropic infusion.
Outcome according to inotrope
The 13 patients who received dopamine spent 86 +/-146 days
per patient as outpatients (70% of the time receiving inotropic
drug therapy), and four (31%) of these 13 patients died. The four
patients who received dobutamine spent a mean of 90 +/- 130
days per patient as outpatients (66% of the time receiving
inotropic therapy), and one (25%) of these four patients died.
The three patients who received a combination of dopamine and
dobutamine spent a mean of 200 +/- 148 days per patient as
outpatients (70% of the time receiving inotropic therapy), and
two (67%) of these three patients died. Deaths were related to
the underlying diagnosis rather than the inotropic drug that was
used.
Readmissions
There were 54 readmissions overall, with an average of 2.7
readmissions per patient. Readmissions were required for
worsening of heart failure,[16] line changes,^221 treatment of
infected lines,[5] or intercurrent illness (10 total: respiratory tract
infection, 5; unstable angina pectoris, 2; transient neurological
ischemic attack, 1; cholecystitis, 1; and acute gout, 1).
The six patients with idiopathic dilated cardiomyopathy required
fewer readmissions (1.0 per patient) than did the nine patients
with ischemic cardiomyopathy (2.4 per patient, p = 0.69) or the
three patients with right ventricular heart failure (5.7
readmissions per patient,/? = 0.38).
The 13 patients who received dopamine required 2.2
readmissions per patient while the four patients who received
dobutamine required 2.2 readmissions per patient. The three
patients who received the combination of dopamine and
dobutamine required 5.3 readmissions per patient (p = 0.08).
There was a trend toward more readmissions in the seven
patients who ultimately died (4.3 per patient) than in the 10 who
received transplantation and the three who still await heart
transplantation (1.8 per patient,/? = 0.16).
Line changes
Line changes were required for infection, leakage, inadvertent
removal, or occlusion of the line. Twenty-two line changes were
required (1.1 per patient). The seven patients whose conditions
deteriorated and later died had more frequent line changes (1.6
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per patient) than the 10 who received transplantation and three
who await heart transplantation (0.6 per patient), but this was not
statistically significant (p = 0.1 1). The tunneled subclavian
silastic catheter frequently lasted up to 6 months without
problem.
Costs
The cost of therapy with dopamine is $35 per day, dobutamine
$45 per day, clinic visits $30 per visit, and disposables $10 per
day (including lines, fluid, batteries, dressings, etc.). The average
cost of 1 day on home inotropic therapy is therefore
approximately $60.
In our institution, the cost of 1 day in a step-down ward is $380
(excluding medical staff, investigations, and drug therapy).
Coronary intensive care beds cost $870 per day. The mean
proportion of occupancy of a coronary care bed by this group of
patients was 10% of the admission. The averaged bed cost
(ward/critical care unit ratio = 9:1) was therefore approximately
$430 per day. This cost yields a saving of $370 for every day of
home ambulatory inotropic drug therapy. The total amount saved
for all 20 patients, with more than 3000 days spent as
outpatients, was approximately $1,107,000, or an average of
$55,350 per patient.
This is the largest report of continuous home intravenous
inotropic therapy. Long-term, continuous home ambulatory
inotropic therapy is easily administered and can be given after a
brief period of instruction with few readmissions or significant
complications. Home ambulatory inotropic therapy allows
patients not previously able to leave the hospital to enjoy a more
normal lifestyle at home. It was associated with a 70% mean
reduction in hospital bed occupancy for patients with severe
heart failure. The time spent out of hospital lead to a savings of
more than $1 million and liberated hospital beds, allowing more
efficient use of health resources.
Those patients whose conditions deteriorate and are removed
from the waiting list for cardiac transplantation are able to
continue to receive this therapy—extending the proportion of the
terminal phase of their illness, which can be spent as an
outpatient. Those with idiopathic dilated cardiomyopathy
derived the greatest clinical benefit from home ambulatory
inotropic therapy, whereas those with primarily right ventricular
failure and older patients with ischemic cardiomyopathy
appeared to benefit least. This finding is not surprising because
the patients with idiopathic dilated cardiomyopathy were
younger and less likely to have concomitant vascular disease and
renal dysfunction at baseline.
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The patients and their families did not report anxiety about
preparing the infusions. The syringe pump was reloaded by the
patient every 6 to 8 hours, allowing adequate time for sleep. The
small inaccuracy of delivery by the syringe driver over an 8-hour
infusion period did not appear to be clinically important. These
patients were not critically inotrope dependent and could be
without the inotropic drug infusion for a few hours without
immediate deterioration;19'20'23'24'39'40]
Long-term inotropic therapy was not associated with sudden
death. We attribute this to the use of amiodarone in those with
ventricular tachycardia on monitoring. All seven deaths were
from progressive heart failure. The poor outcome in two of the
three patients with right heart failure was greatly affected by the
lack of a suitable heart-lung donor. Both patients received
intravenous inotropic therapy for more than 1 year and were on
the active transplant waiting list during this period. They may
have had a different outcome had a suitable donor been
available. The actuarial survival of 71% at 3 months is similar to
that of patients who are inotrope dependent.[28]
The technique of a tunneled subclavian silastic (Vygon) catheter
has now been adopted by our unit for all patients with heart
failure requiring inotrope or vasodilator infusions for more than
a few days. The procedure reduces the need for further line
changes, preserves central venous access and can be performed
safely under local anesthesia with a very low complication rate
and without cessation of anticoagulation. This also reduces costs
and inpatient duration. In contrast, most other studies used
Hickman catheters, which require general anesthesia for
insertion and temporary conversion from warfarin to
subcutaneous heparinJ11"18'243
Despite inotropic therapy improving hemodynamics after shortterm therapy in moderate to severe heart failure,[41] there is
concern that long-term use may increase ventricular ectopy,
predispose to arrhythmia, increase ventricular response rate in
atrial fibrillation, and exacerbate the functional valvular gradient
in aortic stenosis.[21>22'42"45] Earlier studies with ambulatory
inotropic therapy[16'17] preceded the era of angiotensin-converting
enzyme inhibitors and more effective antiarrhythmic therapy in
heart failure. Intermittent infusions may also predispose toward
increased mortality rate. Recent studies by Miller^11! and the
Loyola group[46] report no excess mortality rate in patients
treated with ambulatory inotropic therapy with current adjuvant
therapy including ACE inhibitors. The mortality rate in these
studies compares favorably with ours (Table V).
Two recent studies[25'29] indicate reduced mortality rate from
sudden death and progressive heart failure with low-dose
amiodarone. Amiodarone was used in 50% of our patients and
may have contributed to electrical stability.[25-31]
Adoption of home ambulatory inotropic therapy has been limited
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because of concern about an increased risk of arrhythmia or
sudden cardiac deathJ11-18] Most previous studies used either
intermittent home ambulatory inotropic infusions given for a few
days per week or attempted to wean the infusion at regular
intervals.[1M8] The intermittent use of inotropic therapy may,
however, heighten sympathetic activity by countering Badrenoreceptor downregulationJ4'5'8'9'19"23'39'41] This may increase
the response to inotropic agents but may also increase the
potential for arrhythmia and introduce the risk of weaning
therapy, possibly exacerbating the underlying heart failure.
[4,5,8,9,19-23,39-41] Conversely, chronic B-receptor downregulation
may also protect against arrhythmogenesis.[21~23'41'42] Although no
patients in our cohort were receiving B-adrenoreceptor blocking
agents, the B-blocking effects of amiodarone may afford some
protection from arrhythmias in this respect.[25'31]
It is difficult to determine whether tolerance developed. All 20
patients remained receiving a stable dosage of inotropes. In no
case was an increase in dosage required; however, there was no
significant change in hemodynamics after 7 days of inotropic
therapy. This may have been because of the small number of
patients in the study or because of tolerance. Seventy-five
percent of patients required readmission for progressive heart
failure (30% of all readmissions). Development of tolerance may
have caused deterioration in some of these patients. Our
impression, however, was that underlying progression of heart
failure was the major cause of deterioration rather than tolerance.
Use of long-term inotropic therapy remains a controversial issue.
Low-dose dopamine (<=4.5 mcg/kg/min) has been shown to
increase diuresis and cardiac output without vasoconstriction or
proarrhythmic effect and has been shown to be safe in the shortterm. t6'7'14'45! Higher doses of dopamine have been predominantly
used for contractile augmentation. The majority of patients in
this study received low-dose dopamine, which is in contrast to
other studies (TableJV). Low-dose dobutamine (<=5
mcg/kg/min) has been shown to exert a predominantly
vasodilatory effect, whereas higher doses exert an inotropic
effect.[6>7'14'45] Studies to date have used different drugs, dosages,
and administration schedules and their results require individual
consideration.
Miller et alJ12] treated 11 patients with continuous vasodilatory
doses of dobutamine (up to 5 mcg/kg/min) rather than the higher,
inotropic doses used in our study. Weaning, attempted at regular
intervals, was possible in seven of the 11 patients. Average
duration of inotropic therapy was 3.2 months (range 2.9 to 5.4
months). There were no sudden deaths or significant
arrhythmias. Four of the 11 patients died because of disease
progression. There was reduced hospital bed occupancy.[12]
In an expanded report by Miller et al.,[n 33] patients were treated
with continuous dobutamine for 2 weeks. They then attempted to
wean therapy by slowly reducing the number of days of
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inotropic support per week. The maximum duration of
intermittent inotropic therapy was 11 months (mean 4.1 months).
The dosage of dobutamine was lower than in our study and no
patient received more than 5 mcg/kg/min as an outpatient.[11]
Unlike previous studies, but as in ours, patients were actively
listed for transplantation at the time of inotrope commencement,
amiodarone was used for symptomatic high-grade ventricular
ectopy, and angiotensin-converting enzyme inhibitors and full
anticoagulant therapy were routinely used. There were two
sudden deaths in this study (neither of these patients received
antiarrhythmic therapy), and there were 2 deaths caused by
pulmonary thromboembolism from the central venous catheter.
[11]
Unlike our experience, this study used a home health nurse.
Krell et al.[17] treated 13 patients with dobutamine for 48 hours
per week (mean dose 7.5 mcg/kg/min) over a 26-week period
and found a 54% functional improvement. However, only 23%
survived the trial and 46% died suddenly^17! This group was not
as large as ours, used a higher infused concentration of
dobutamine, and the patients were not all receiving maximally
tolerated doses of ACE inhibitors, digoxin, vasodilators, and
amiodarone. This is particularly important because two of three
survivors were receiving amiodarone compared with none of
those who died.[17]
Applefield et al.[14] treated 11 patients with intermittent
dobutamine for 48 hours per week. An additional six patients
received continuous dobutamine and four patients received
continuous dobutamine plus dopamine over a 4-year period.
There was a significant improvement in functional class, but 20
of the 21 patients died (including four sudden deaths).
Concomitant therapy again was different from our group, and no
patients underwent transplantation.^ Our current policy is that
when commencing continuous, long-term home ambulatory
inotropic therapy, cardiac transplantation should be the goal-otherwise therapy may be prolonged beyond a continued highquality existence.
Dies et al.[16] conducted a multicenter, randomized, placebocontrolled, double-blinded trial of outpatient intermittent
dobutamine therapy (mean dose 8.1 mcg/kg/min, maximum dose
15 mcg/kg/min) in 60 patients, but the study was terminated
prematurely because of increased adverse outcomes; 40% of the
patients treated with dobutamine died (half of which were
sudden deaths) versus 22% of patients receiving placebo, despite
improvement in symptoms and exercise duration.[16] The patients
with significant arrhythmias during the initial "run-in" phase
were the patients who subsequently had the highest mortality
rate. No patients in this study received antiarrhythmic therapy.
The mortality rate in our study compares favorably with that of
these previous studies (TableJV), although our patients were
slightly younger because all were on the transplant waiting list.
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The financial advantage of home ambulatory inotropic therapy
may be currently lost in the United States, where discharge of
patients from the coronary care unit may lessen patient priority
for heart transplantation and reduce reimbursement. This is
likely to change as health providers explore new avenues for cost
containment. We believe that patients who remain listed for
transplantation should remain status 1 (highest priority). At
present, there is no indication that their survival is improved by
home inotropic therapy, and their progress can be considered to
be similar to that of patients with class IV heart failure requiring
intravenous inotropic support in the hospital.
When patients receiving home ambulatory inotropic therapy
become unsuitable for transplantation, it can be difficult to
withdraw therapy. In our experience under these circumstances,
the infusion has been continued at the patient's insistence. For
this reason, home ambulatory inotropic therapy is no longer
instituted in marginal patients with substantial renal dysfunction
or in older patients, who are more likely to become unsuitable.
At present there is insufficient evidence to recommend home
inotropic therapy as a treatment modality per se, except possibly
in patients with idiopathic dilated cardiomyopathy who respond
very well to ambulatory inotropic therapy.
A goal of our analysis was to identify which patients benefit
least from home ambulatory inotropic therapy. Patients with
right ventricular heart failure caused by pulmonary vascular
disease and older patients with ischemic cardiomyopathy appear
to have more extra-cardiac disorders, and careful consideration
of such therapy in these patients may prevent long and
complicated courses of therapy with a poor outcome. Patients
with idiopathic dilated cardiomyopathy appear to benefit most
from home inotropic therapy. These younger patients were more
likely to survive to transplantation and had less comorbidity. On
the basis of our results, we do not recommend this therapy for
patients with right ventricular heart failure. We carefully
consider older patients, particularly those with comorbid disease
or high-risk candidates for heart transplantation. We are
currently carrying out a controlled, randomized trial of inotropic
therapy against alternative therapies to assess the risks and
benefits of such treatment.
Because heart failure is a common and incapacitating
condition 1-3 and the hemodynamic and symptomatic status of
these patients can be improved with inotropic therapy, such
treatment may be vital in the management of these patients.[4'9]
The considerable relief gained by inotropic therapy of symptoms
such as breathlessness, dizziness, nausea, edema, and bloating
are of great relief to this debilitated group of patients and should
not be underestimated or necessarily withheld because of
theoretical concerns over possible adverse effects. Because a
certain subgroup of these patients will become "inotrope
dependent," the place of home ambulatory inotropic therapy is
an important link as a "bridge to transplant," particularly in view
http://www.medscape.com/mosby/AmHeartJ/1997/vl34.n05/ahjl345.08.sind/ahjl345.... 10/12/2001