Enoxiparin for long-term anticoagulation with the pediatric EXCOR ...

doi:10.1510/icvts.2005.114694
� 2005 Published by European Association for Cardio-Thoracic Surgery
ARTICLE IN PRESS
Interactive CardioVascular and Thoracic Surgery 4 (2005) 561–562
www.icvts.org
Case report - Assisted circulation
Enoxiparin for long-term anticoagulation with the pediatric EXCOR
left ventricular assist device
a, a b a
Daniele Camboni *, Christof Schmid , Georg Rellensmann , Tonny D.T. Tjan
aDepartment
of Thoracic and Cardiovascular Surgery, Klinik für Thorax-, Herz- und Gefäßchirurgie, Albert-Schweitzer Straße 33, D-48149 Münster, Germany
bDepartment
of Pediatric Cardiology, University Hospital Münster, Germany
Abstract
Received 9 June 2005; received in revised form 2 July 2005; accepted 4 July 2005
We report on an 8-month-old child with end-stage heart failure, which was successfully transplanted after 5 months of mechanical
circulatory support with the Excor Berlin Heart system using low molecular weight heparin instead of an oral anticoagulation.
� 2005 Published by European Association for Cardio-Thoracic Surgery. All rights reserved.
Keywords: Pediatric heart failure; LVAD; Anticoagulation
1. Introduction
In pediatric patients, end-stage heart failure is rare but
usually fatal. Cardiac transplantation remains the treatment
of choice in most cases, but unfortunately it cannot
be performed in many cases due to the tremendous shortage
of donor hearts w1x. To solve this problem mechanical
circulatory support devices were increasingly used to bridge
children to heart transplantation. In Germany, the Medos
device w2x and the Excor Berlin Heart have been introduced
into clinical practice w3x. We report on a child with endstage
heart failure, which was successfully bridged to
cardiac transplantation for more than 5 months with the
Excor Berlin Heart using low molecular weight heparin
instead of oral anticoagulants like e.g. phenprocoumon for
long-term anticoagulation.
2. Case report
An 8-month-old female child (7200 g, 74 cm, body surface
2
area 0.38 m ), with a previous normal development, presented
to a rural hospital with a two-week history of
vomiting, dehydration and acidosis. Soon after admission,
echocardiography revealed a dilated heart. The young
patient was immediately transferred to a specialized pediatric
cardiology department. Repeated echocardiography
confirmed dilative cardiomyopathy with a shortening fraction
of 10% and a left ventricle diastolic diameter of
48 mm. Despite the use of beta-blockers, diuretics, angiotensin-converting-enzyme-inhibitors
and digitalis the clinical
condition deteriorated and admission to an intensive
care unit with continuous inotropic support became necessary.
The little patient was transferred to our university
*Corresponding author. Tel.: q49 251 834 7402; fax: q49 251 834 8316.
E-mail address: daniele.camboni@ukmuenster.de (D. Camboni).
hospital for evaluation of cardiac transplantation. At admission,
the child was awake, had spontaneous breathing, with
systolic and diastolic heart murmurs under inotropic support
and with no signs of neurological impairment. Blood
tests were normal apart from a BNP (Brain Derived Natriuretic
Protein) of 22173 Uyl and slightly elevated liver
enzymes. No obvious cause for the severe heart disease
was found. When cardiovascular collapse mandating resuscitation
occurred, a paracorporeal pneumatically driven
Excor left ventricular assist device utilizing a 25 ml chamber
was placed (Berlin Heart AG, Berlin, Germany). During
extracorporeal circulation a 6-mm inflow cannula was
inserted into the left ventricular apex and a 6-mm outflow
cannula was connected to the ascending aorta. The pump
flow was adjusted to 2.4 lymin. Within a few days the girl
stabilized and she could be weaned from inotropic support.
The initial anticoagulation merely consisted of i.v. heparin
at a dosage of 400 units per kilogram body weight per day,
guided by the aPTT (60–80 s). After removal of chest tubes,
aspirin (5–30 mgyd) and clopidogrel (1–10 mgyd) were
added to the anticoagulation regime. Its dosage was titrated
to achieve a platelet inhibition of 70% or more during
¨
aggregometry (PAP-4, Molab, Berlin). On postoperative day
33 i.v. heparin was replaced by low molecular weight
heparin (LMWH) (enoxiparin 10–15 mgyd), subcutaneously,
once a day. The effect of LMWH was monitored by measurements
of anti-Xa levels, where a target range of 0.5 to
1.0 Uyml was considered optimal (Fig. 1).
The further postoperative course was uneventful until day
124, when a transient ischemic attack occurred manifestating
as an incomplete hemiplegia. The subsequently performed
cranial CT scan was normal. The pump chamber
was exchanged as a small thrombus deposition was evident
(Fig. 2). The little patient recovered totally without any

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562 D. Camboni et al. / Interactive CardioVascular and Thoracic Surgery 4 (2005) 561–562
Fig. 1. Time course of anti-Xa levels during mechanical circulatory support.
neurological impairment. A follow-up CT scan before discharge
revealed a small hypodense subcortical lesion less
than 1 cm in diameter. On day 154 of mechanical circulatory
support a suitable donor organ was found and a
successful orthotopic cardiac transplantation was
performed.
3. Discussion
Pediatric long-term mechanical support is challenging as
bleeding and thrombembolic complications frequently
occur w4x. This case offers different interesting information.
First of all, the pediatric Excor system allows mechanical
support beyond 100 days with an acceptable risk. A comparable
experience has been reported by the inventors of
the Berlin Heart, which supported 18 children for a mean
of 20 days w5x. We noticed a small thrombus deposition
inside the pump chamber, which may occur early. As a very
tiny thrombus deposition is empirically harmless and a
pump exchange associated with certain risks (thrombus and
air embolism!), we do not aggressively exchange pump
chambers. Instead, we optimize anticoagulation and antiaggregation.
Only in case of large thrombus formation or
after an adverse neurological event we exchange the pump
chamber. In our case, the latter could be easily performed
on the intensive care unit within a few minutes. Moreover,
this case proves the possibility of using subcutaneous
administered LMWH instead of coumadin or phenprocoumon
as oral anticoagulants. Its efficacy can be monitored by
measuring anti-Xa levels and kept rather stable over a long
Fig. 2. Exchanged pump chamber demonstrating a small thrombus deposition
(arrow) underneath the outflow valve.
period of time w6x. Additional platelet inhibition with aspirin
and clopidogrel does not interfere.
In conclusion, this case illustrates that LMWH could be a
simple and reliable alternative during long-term support
with the pediatric Excor system. Further experience in a
larger patient population is necessary to evaluate the safety
of this new approach in comparison to the established
anticoagulation strategies.
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