Pathology of pulmonary venous obstruction after total anomalous pulmonary venous connection repair
Some authors indicate the following pathologies as the causes of PVO after conventional TAPVC repair: 1) thickened pulmonary vessel walls, 2) pulmonary lymphangiectasia, and 3) surgical anastomotic stricture (14,15). Although PVO is usually a serious condition that directly leads to death (1,2), our five patients of seven patients with postoperative PVO survived. All PVOs were local branch PVOs and did not show severe stenosis. The overall PV function was therefore maintained sufficiently for Fontan candidates except one patient who died after Fontan. The sutureless technique, using a large circular anastomosis, may have prevented the three abovementioned pathologies after conventional TAPVC repair. Although a single PVO is usually well tolerated, any minor PVOs may affect the long-term results of congenital heart disease.
In the present study, we hypothesized that the following two anatomical factors that narrow the space behind the heart were associated with postoperative PVO: 1) the anatomical relationship between the arch and apex, i.e., whether they are present on the same side or not, and 2) apex rotation into the thoracic cavity. Both factors may exaggerate the compression of PVs. Although our hypothesis 1) i.e., the anatomical relationship between the arch and apex, was denied, the relationship between heart apex and PVO was very likely. Furthermore, a change in the V-A angle, indicating apex rotation, was evident in the PVO group. We speculate the mechanism of apex rotation into the ipsilateral thorax and the relationship between apex rotation and postoperative PVO as follows: the apex rotation would be attributed to the fact that the pericardium was left open after surgery. Furthermore, the amount of the tissue surrounding the suture line may have affected PVO: especially, since sutureless technique needs a large anastomotic site, the area in contact with the surrounding tissue is also large. Thus, the suture line would be easily affected by surrounding tissue. In all six PVO cases, the lower PV branch in the apex side was diffusely stenotic as indicated in Fig. 1B.
Any modifications of the currently available techniques, e.g., more reduction of the surrounding tissue by resecting posterior wall of the atrium might decrease the incidence of postoperative PVO. Although we attempted to prevent the rotation of the apex into the thoracic cavity by fixing or closing the pericardium, we had to reopen the pericardium in all patients due to low cardiac function during or early after the surgery. We, therefore, could not prove the effectiveness of this strategy.