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.