CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 1, January/February 2013
AFRICA
29
was performed at 5.3
±
0.7 day of life. Mean blood lactate level prior
to iPBFR was 7.8
±
1.9 mmol/l, and mean arterial oxygen saturation
was 89.8
±
7.6%. Mean blood lactate level after iPBFR was 1.8
±
0.8
mmol/l, and mean arterial oxygen saturation was 77.8
±
5.3%. One
patient died 20 hours after the procedure due to progression of organ
dysfunction. The rest of the patients remained stable and underwent
the Norwood procedure at 5.6
±
2.8 days after the initial palliation.
Conclusions:
Invasive pulmonary blood flow restriction reduces
systemic hypoperfusion, improving the metabolic status and stabilis-
ing patients’ condition before the Norwood procedure.
652: LONG-TERM SURVIVAL IN PIGLETS AFTER
SECTIONING AND RE-SUTURING VESSELS MIMICKING
THE ARTERIAL-SWITCH PROCEDURE FOR TRANSPOSI-
TION OF THE GREAT ARTERIES
Cecilia Falkenberg, Stefan Hallhagen, Krister Nilsson, Boris Nilsson,
Peter Friberg, Ingegerd Östman-Smith
Sahlgrenska University Hospital, Sweden
Background:
Children born with transposition of the great arteries
undergo an arterial-switch operation (ASO) in the neonatal period.
The ASO sections the sympathetic nervous inflow along the aorta
and coronary arteries. Experiences of long-term follow up after ASO
indicate that the autonomic nervous system consequences of the ASO
need to be addressed. We developed a protocol for cardiopulmonary
bypass (CPB) surgery in piglets allowing long-term survival after
sectioning and re-suturing vessels as in the ASO. Post-operative care
without intensive care unit facilities was a challenge.
Methods:
Female piglets of Yorkshire–Hampshire crossbreed, aged
8.5 weeks were operated. Anaesthesia combining paediatric anaes-
thetic ICU and veterinarian experience included pre-operative seda-
tion with midazolam/ketamine, induction and maintenance with
propofol and fentanyl in combination with isoflurane inhalation.
Lidocaine was infused to prevent arrhythmias. Standards for neonatal
monitoring were applied. CPB equipment: oxygenators, circuit and
pumps, were adapted to the range of flow and venous drainage, and
cross-matched pig blood was added to the prime. The surgical tech-
nique had to be adapted to the different position of the the piglet’s
heart and large vessels. The protocol was approved by the local
animal research ethics committee. Animal welfare rules forbidding
division of the manubrium in pigs that must be able to stand after
the operation added surgical difficulties. Special rigging of the aortic
arch was necessary for cannulation and access. In addition, fragile
tissues resulted in suturing difficulties. Re-warming to body tempera-
ture of 38°C before extubating was essential.
Results:
Fourteen out of 19 piglets that underwent the mimicked
ASO survived for long-term follow up and later
in
vivo
and
in
vitro
analysis of the physiological consequences of sympathetic denerva-
tion of the heart caused by the sectioning of the large vessels and the
re-implantation of the coronaries.
Conclusions:
This model can be used to enhance the knowledge of
the short- and long-term consequences of paediatric cardiac surgery.
656: VARIABILITY IN RESPONSE TO AMLODIPINE IN
HYPERTENSIVE PAEDIATRIC CARDIAC TRANSPLANT
RECIPIENTS
Fatima Fazalullasha, Ashok Kumar Manickaraj, Paul Kantor, Seema
Mital
Hospital for Sick Children, Toronto, Canada
Background
: Fifty to 70% of paediatric cardiac transplant patients
develop late-onset hypertension. Amlodipine, a calcium channel
blocker, is the most commonly used first-line antihypertensive agent.
Objective
: To analyse the efficacy of amlodipine as first-line therapy
for hypertension in paediatric cardiac transplant recipients.
Methods
: Paediatric cardiac transplant recipients prospectively
enrolled through the heart centre biobank were studied. Twenty-four-
hour, daytime and night time mean systolic and diastolic blood pres-
sure (BP) were captured from serial ambulatory BP measurements.
Hypertension was defined as being above the 95th percentile in BP
for gender, age and height. Amlodipine dose and BP indexed to
amlodipine dose (in mg/kg/mmHg × 100) was assessed.
Results
: Of 124 heart transplant patients in the biobank, 53% were
male (mean age, 11.8 years at enrollment; 74% were white, 11%
Asian, 4% black, 10% other). Ninety-seven received amlodipine
during follow up. Of 97 patients in whom ambulatory BPs were avail-
able, 21 were analysed. Mean dose of amlodipine was 0.165 mg/kg/
day (range 0.054–0.355). The BP indexed to amlodipine dose was
highly variable.
Conclusions
: There was large variability in amlodipine dose require-
ments and dose-adjusted response to amlodipine in hypertensive
paediatric transplant patients. Genetic testing is underway to deter-
mine the contribution of pharmacogenetic variation to the amlodipine
response. This knowledge will help in optimising the choice and dose
of first-line antihypertensive therapy in this cohort.
661: PULMONARY VALVE IMPLANTATION USING SELF-
EXPANDING TISSUE VALVE
Stefano Marianeschi
1
, Nicola Uricchio
1
, Massimo Caputo
2
, Antonio
Amodeo
3
, Nicola Viola
4
, Ricardo Gomez
5
, Juan Comas
6
, Ozkan
Suleyman
7
, Simone Ghiselli
1
, Gabriele Vignati
8
1
Niguarda Hospital, Milan, Italy
2
Royal Children’s Hospital, Bristol, UK
3
Bambino Gesù Hospital, Rome, Italy
4
University Hospital, Southampton, UK
5
Ramon y Cajal Hospital, Madrid, Spain
6
12 de Octubre Hospital, Madrid, Spain
7
Baskent University Hospital, Ankara, Turkey
8
Niguarda Hospital, Milan, Italy
Introduction
: Significant pulmonary regurgitation is a common
problem after surgical or percutaneous treatment of congenital
cardiac defects such as tetralogy of Fallot, negatively affecting long-
term prognosis and necessitating re-interventions. The bio-integral
no-react injectable pulmonic (NRIP) valve allows pulmonary valve
replacement with or without cardiopulmonary bypass (CPB), mini-
mising the impact of surgery. The aim of the work was to describe
our multi-institutional experience with the clinical use of this device.
Methods
: Between January 2006 and June 2012, 35 symptomatic
patients, mean age 20.0
±
12.5 years, with severe pulmonary regur-
gitation and progressive right ventricular dysfunction after tetralogy,
received NRIP in 11 different European institutions. All patients
underwent magnetic resonance (MR) before and after the implant and
transoesophageal 2D echocardiography during the surgical procedure
and follow up.
Results
: Valve insertion, delivery and placement were successful
in all patients but two that required the repositioning of the same
valve in CPB. Of these, five patients implanted the valve in CPB to
allow repair of intracardiac defects. Early recovery was uneventful
and all the patients were discharged home after a mean length of
hospital stay of 6.3
±
2.4 days. Intra-operatively, transoesophageal
echocardiography was the unique tool to guide device positioning
and verify early surgical results. In three patients echo documented
a valve displacement after delivery and guided the repositioning. In
the postoperative course, serial echocardiographic and MR studies
documented right ventricle reverse remodelling and excluded later
complications. The mean follow up was 3.8 years.
Conclusions
: The NRIP valve allows safe and easy pulmonary valve
replacement without CPB in selected cases. Its mode of implantation
offers a less-invasive approach with less blood loss and shorter hospi-
tal stays. Transoesophageal echocardiography plays an important role
in the intra-operative management and the MR permits an adequate
selection of patients. Longer follow up is required to assess valve
performance.
