Branch pulmonary artery growth after Blalock-Taussig shunts in tetralogy of Fallot and pulmonary atresia with ventricular septal defect: A retrospective, echocardiographic study

We performed a retrospective echocardiographic study in tetralogy of Fallot (TOF) or pulmonay atresia with ventricular septal defect (PA&VSD) to evalu ate the effects of Blalock-Taussig shunt on branch pulmonary artery growth. Then were 35 patients with TOF and 11 with PA&VSD. We measured the right a nd left pulmonary artery area index and also the combined pulmonary artery area index, both before and after shunt operation. The mean +/- SD of these three variables before the shunt operation in the TOF group were 63.5 +/- 22.5, 57.8 +/- 24.9, and 121.4 +/- 42.8 mm(2)/m(2); after shunt operation t hey were 98.5 +/- 33.6, 85.9 +/- 31.9, and 184.0 +/- 59.8 mm(2)/m(2), respe ctively (p values <0.0001, <0.0002, and <0.0001, respectively). In the PA&V SD group the comparable values before shunt operation were 66.5 +/- 16.0, 5 5.4 +/- 10.6, and 120.9 +/- 26.9 mm(2)/m(2) and after shunt operation were 90.5 +/- 22.9, 77.2 +/- 24.1, and 166.6 +/- 44.4 mm(2)/m(2), respectively ( p values <0.0006, <0.014, and <0.002, respectively). We also examined the e ffect of distensibility of pulmonary arteries by comparing the percentage c hange in size of the combined pulmonary artery area index in the first 4 mo nths after shunt with those after this time (p < 0.023). There were no sign ificant differences between left- and right-sided shunts, origin and distal pulmonary artery growth, and the TOF and PA&VSD groups.