Materials and methods
The institutional review board at Pusan National University Yangsan Hospital approved the present study, and the patient consent was waived for the retrospective data analysis (IRB No. 05-2018-178). We have adopted the posterior aortopexy technique to treat left PV obstruction caused by compression between the LA and the DA in five patients (three female) since August 2012. The median age and weight of the patients at the time of operation were 5.5 months (range, 1-131 months) and 5.2 kg (range, 4.2-29.5 kg), respectively. When the patient revealed a turbulence flow or peak pressure gradient (PG) of 10 mmHg or more, or showed a continuous, non-phasic flow pattern on the echocardiography, the condition was deem to be an obstruction of the corresponding PV1,10, and then the position and shape of the pulmonary vein obstruction was confirmed by using computed tomography (CT) angiography 11. All five patients but one were initially diagnosed with the left PV obstruction on the echocardiography. In one patient, the left PV obstruction was diagnosed with CT angiography and cardiac catheterization. This patient showed a distended inferior vena cava in follow-up echocardiography after the Fontan procedure. The CT angiography performed for further evaluation showed left PV obstruction between the LA and the DA (Fig. 1A). A sharp demarcation of the left PV flow at the DA border was also noticed in the levophase of pulmonary angiogram (Fig. 1B). The compressed PV pattern was identified on preoperative CT angiography: focal stenosis in three patients, focal and diffuse stenosis in one patient, and diffuse stenosis in one patient. The median preoperative peak PG across the obstructed left PV was 7.3 mmHg (range, 4-20 mmHg) in all five patients, and concomitant procedures were performed in two patients. Table 1 summarizes the baseline characteristics of the patients.
Posterior aortopexy was carried out through left thoracotomy (the fourth intercostal space (ICS) in one patient, the fifth ICS in three patients, and the sixth ICS in one patient). The DA was fixed to the posterior chest wall using Teflon pledget-buttressed 3-0 or 4-0 polypropylene sutures (Fig. 2A and B) 6,12. To evaluate the appropriateness of the posterior aortopexy technique, we measured the change in the angle between the DA and the vertebra on CT angiography before and after the operation. A horizontal line was made from the center of the vertebra, and the other line was drawn from the center of the vertebra to the center of the DA in the axial slice at the level of left PV obstruction (Fig. 3A, inlet). Subsequently, we checked the angle between the two lines before and after the operation on CT angiography, and the change in the angle (ㅿa) was calculated by using the formula mentioned below.
ㅿa = a – a’
a = preoperative angle between the DA and the vertebra (Fig. 3A)
a’ = postoperative angle between the DA and the vertebra (Fig. 3B)
If the value of ㅿa is positive, the posterior aortopexy is considered to be performed effectively.
The data were collected and managed with Microsoft Excel 2016 (Microsoft, Redmond, Wash) and the Statistical Package for Social Sciences, version 25 (SPSS, Inc., Chicago, Ill). The continuous variables are expressed as a median and range.