Discussion:
There are several techniques described to create confluence and enlarge
LPA. Enlargement with autologous pericardium (fresh / pre-treated),
bovine pericardium, Gore-Tex patch / tube, Dacron grafts, homografts,
resection with end to end anastomosis have been
reported2. However, all these techniques have a high
rate of restenosis which is largely attributed to extension of ductal
tissue into the LPA, scarring, fibrosis and cicatrisation of autologous
pericardium3. Other rare but well-known complications
apart from re-stenosis are pulmonary artery-venous fistulas that require
re-operation4,5.
In our patient, the autologous tissue form the MPA was used to
accomplish the reconstruction. The pulmonary end of the transected MPA
was turned down as an extension to recreate tissue-tissue anastomosis
between the pulmonary arteries. In our patient, there was a normal MPA
above the atretic pulmonary valve and it continued as a normal RPA.
There was fairly good length of MPA that continued as a normal RPA. It
was critical that to avoid torsion while turning down the transected MPA
towards the left hilum and hence two marker sutures were placed in the
opposite directions for identification. Thus, transecting the MPA and
turning down to left hilum and connecting it to transected LPA did not
pose any difficulty and helped create a tension-free anastomosis. Being
native autologous tissue, it is resistant to infection and
calcification, free from autoimmune responses, has distensibility and
potential for growth unlike pericardium, bovine pericardium, synthetic
prosthetic materials. There is no loss of tissue with consequent tension
across the anastomosis as well unlike in direct transection and
anastomosis in the conventional way. Moreover, it just utilizes the MPA
that is present in the area and has no clinical value in these subsets.
However, this approach applies to very small subset of patients in whom
there is a well formed MPA in the setting of disconnected LPA – not a
frequent combination.