336 Part VII / Nitric Oxide and Cardiovascular Therapeutics
making it a particularly suitable paracorporeal device for the pediatric population. This
device is not available for use in the United States.
The Berlin Heart is a univentricular or biventricular air-driven device, with a unique
three-layered flexible polyurethane blood pump membrane encased within a semirigid
transparent polyurethane housing (Fig. 9). The three membranes are separated from
one another with a graphite powder lubricant to minimize friction. The innermost
membrane, which is the only one that comes in contact with blood, is smooth and
heparin coated. The Berlin Heart blood pumps are available in 80-, 60-, 30-, 25-, and
12-mL sizes. The adult-size pumps are supplied with monoleaflet tilting disk valves
(Sorin Biomedica, Turin, Italy) in the inflow and outflow sides, whereas the pediatric-
size pumps are supplied with heparin-coated polyurethane trileaflet valves, marked by
flat construction, which provides optimal washout behind the leaflets.
A variety of steel-reinforced silicone cannulae, available also in small diameters,
enable the paracorporeal blood pump to be connected to the heart and great vessels
(Fig. 9). The blood pump is operated by a variety of stationary or wearable electro-
pneumatic drive units, each containing redundant drive units for safety. All drive units
are equipped with rechargeable batteries to provide for patient’s mobility.
The Berlin Heart implantation techniques are identical to those of the Thoratec
VAD. Recently, as a left ventricular apical cannula became available, the device was
implanted in several patients who had undergone previous cardiac surgery. To avoid a
repeat sternotomy, the device was implanted by a left lateral thoracotomy using femo-
rofemoral bypass, with the outflow graft anastomosed to the descending aorta (18).
Adult patients assisted by the Berlin Heart are kept on warfarin, aspirin, and dipyri-
damole; pediatric patients are kept on intravenous heparin.
The largest experience with the Berlin Heart VAD has been accumulated at the
Deutsches Herzzentrum Berlin (19). By February 1999, the device had been implanted
in 346 patients, including 34 children under the age of 16 yr. A biventricular support
mode was chosen for 81%, isolated left ventricular support for 17%, and isolated right
ventricular support for 2%. The main indications for support were bridge to transplant
(59%), postcardiotomy heart failure (15%), and posttransplantation cardiac dysfunc-
tion (9%). The overall mean duration of support was 63 d, and the current longest sup-
port period was 525 d on biventricular assistance. Of the adult patients bridged to
transplant, 52% underwent transplantation and 74% of those were discharged. Of the
34 children assisted with the Berlin Heart (aged between 6 d and 16 yr, mean 7.5 yr),
19 (56%) were taken off the device either after complete cardiac recovery or at the time
of transplantation. Of the 14 transplanted children, 10 were discharged.
Intracorporeal Assist Systems
Currently there are two approved intracorporeal assist systems:
1. The HeartMate LVAD (Thoratec Corporation, formerly Thermo Cardiosystems Inc.,
Woburn, MA)
2. The Novacor LVAD (WorldHeart, Ottawa, Ontario, Canada)
THE HEARTMATE LVAD
The HeartMate LVAD is an implantable pulsatile blood pump that is available in
pneumatically driven (implantable pneumatic, or IP) or electrically powered (vented
electric, or VE) (Fig. 10) models. More than 2300 devices have been implanted since
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