Central pulmonary artery anatomy in right ventricular outflow tract obstructions

We reviewed the cine-angiograms of 190 patients with right ventricular outf low tract (RVOT) obstructions for size and anatomy of pulmonary arteries, p atent ductus arteriosus (PDA) acid major aorto pulmonary collateral arterie s (MAPCAs). Patients were grouped into three, Tetralogy of Fallot (TOF) wit h pulmonary atresia (group 1, N=86), TOF with pulmonary stenosis (group 2, N=97) and 7 cases of pulmonary atresia with intact interventricular septum (group 3). Out of 86 patients in group 1, 49 had PDA alone, 30 had MAPCAs a lone, six had both and one had none. In group 2, 31 patients had persistent PDA and one patient had MAPCAS and PDA. A discrete stenosis (DS) of pulmon ary artery was seen significantly more in patients with RVOT obstructions a ssociated with PDA compared to patients without PDA (67/84 vs. 5/96). Out o f the 84 cases with ducti, 53 had stenosis of the pulmonary artery at the s ite of ductus insertion. Thus presence of PDA was an important factor in th e development of DS. The likely cause of pulmonary artery stenosis in TOF w ith PDA may be the opposing flows through RVOT and PDA producing a watershe d effect at the ductus-pulmonary artery junction. Diffuse hypoplasia of pul monary arteries (DH) was seen more significantly in RVOT obstructions assoc iated with MAPCAs, compared to other patient groups (19/36 vs. 14/87). Thes e small pulmonary arteries had no discrete stenosis and this diffuse hypopl asia might be the result of inadequate blood flow during intrauterine life. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.