Discussion
The quest for an ideal conduit to establish RV to PA continuity began in
1964, when Rastelli et al implanted the first valveless pericardial tube
in a patient with pulmonary atresia. (4) It was soon realised that
competent RVOT has its advantages and Ross et al implanted the first
valved conduit in an eight year old boy with VSD pulmonary atresia. (5)
This was closely followed by Rastelli et al when two children with
transposition of great arteries, VSD and pulmonary stenosis underwent
the eponymous Rastelli’s operation. (6) Irradiated cryopreserved aortic
homografts were implanted in all three patients. However, the techniques
of cryopreservation were crude resulting in rapid degeneration of the
homografts. These were replaced by gluteraldehyde preserved porcine
aortic valves mounted in Dacron tube grafts. The midterm outcomes of
porcine xenografts are acceptable but the failure rate at 10 years as
demonstrated by Belli et al was high. (7) The freedom from re-operation
following a Hancock conduit was 98%, 81% and 32% at 1, 5 and 10 years
respectively. (7) By the mid-1980s, the techniques of cryopreservation
process had improved and once again Homografts became the conduit of
choice. Though, homografts had several advantages over Dacron mounted
xenografts, ease of handling being one of them, limited availability in
smaller sizes led to the emergence of another xenograft in the form of
bovine Jugular vein (Contegra, Medtronic Inc). (8,9) The bovine Jugular
vein has a trileaflet valve and it delivered outcomes comparable to
homografts with an added advantage of availability in smaller sizes.
(10) A multi-centre European study by Breymann et al involving 165
Contegra implants found that the results were comparable to homografts.
(11). Another study by Sandica et al involving 444 consecutive
implantation concluded that the bovine jugular veins in RVOT in patients
below 25 years had superior outcomes when compared with cryopreserved
homografts. (10)
The commercially available options to choose from are pulmonary or
aortic homograft, porcine valve in Dacron tube, Porcine valve in bovine
pericardial tube and bovine jugular vein. Though, commercially marketed
conduits are easily available, high cost precludes its wider use in
countries with limited financial resources. The surgeons are often
compelled to use conduits prepared in the operating room from e-PTFE,
Dacron and autologous or bovine pericardium. (12,13) The early and
midterm outcomes of these hand sewn counts have been satisfactory and
comparable with the commercially available options. (14,15)
The majority of the published series with hand sewn conduits have used
PTFE tube graft for the conduit. Our series is perhaps the first where
bovine pericardial sheet is used to construct the conduit. The bovine
pericardium is easy to handle and is haemostatic. One of the drawbacks
of the bovine pericardial conduit is that it calcifies and forms dense
adhesions with the surrounding structures which can complicate the
re-operations. The cost of hand sewn BPCTV is $300 which is one-sixth
of the cost of commercially available Contegra bovine jugular vein
conduit. This cost advantage makes BPCTV an attractive alternative in
low resource environments. The early and midterm results of BPCTV in our
series were acceptable with freedom from re-intervention of 86% at 30
months.