title: Balloon angioplasty for obstructed modified systemic-pulmonary artery shunts and pulmonary artery stenoses.
abstract: OBJECTIVE
  The results of percutaneous balloon angioplasty for obstructed modified Blalock-Taussig (BT) or central shunts and pulmonary artery (PA) stenoses were studied to assess its role as an alternative to second shunt and surgical PA angioplasty.
  
  
  BACKGROUND
  Obstruction of a modified shunt and PA stenosis related to the shunt or ductus are not infrequent. A second shunt with or without PA angioplastv is required if the PA size, morphology or age of the patient is suboptimal for definitive surgery.
  
  
  METHODS
  From June 1994 to May 1999, balloon angioplasty for obstructed systemic-to-PA shunts was performed in 46 patients, with ages ranging from 1 month to 7.4 years (2.2 +/- 1.9 years). Among the 46 patients, 32 had modified BT shunts, 5 had bilateral shunts, 7 had modified central shunts, and 2 had both modified BT and central shunts. Stenoses were seen in 27 main branch PAs, and interruption was present in three. A concurrent balloon angioplasty was attempted in 28 main branch PAs, but it was performed in only 25 vessels.
  
  
  RESULTS
  Balloon dilation for obstructed modified shunts was considered to be effective in 42 patients (91%), while angioplasty for PA stenosis was effective in 14 vessels and not effective in 11 vessels. After balloon dilation angioplastv, oxygen saturation in the aorta increased from 74.4 +/- 4.3% to 80.8 +/- 3.6% (p < 0.01) in these 46 patients. One patient died of pneumonia. Eight patients required an additional modified BT shunt soon after the procedure because of severe stenosis or interruption at main branch PA. After a mean follow-up period of 11.6 +/- 5.4 months, 29 patients underwent a repeated imaging study to evaluate the morphology and size of the PAs. Of these 29 patients, 26 underwent open-heart surgery, with two mortalities.
  
  
  CONCLUSIONS
  When a second shunt is under consideration because of obstruction of the modified shunt, balloon angioplasty is a possible alternative procedure. Pulmonary artery stenosis, if present, can be simultaneously dilated.
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei. jkw@ha.mc.ntu.edu.tw
authors.forename: J K
authors.initials: JK
authors.lastname: Wang
authors.forename: M H
authors.initials: MH
authors.lastname: Wu
authors.forename: C I
authors.initials: CI
authors.lastname: Chang
authors.forename: I S
authors.initials: IS
authors.lastname: Chiu
authors.forename: H C
authors.initials: HC
authors.lastname: Lue
mesh_terms: D000800:Angioplasty, Balloon; D019917:Blood Vessel Prosthesis Implantation; D002648:Child; D002675:Child, Preschool; D003251:Constriction, Pathologic; D005260:Female; D006083:Graft Occlusion, Vascular / Q000628:therapy*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011651:Pulmonary Artery / Q000473:pathology*; D011859:Radiography; D013348:Subclavian Artery / Q000000981:diagnostic imaging