title: Transverse arch hypoplasia predisposes to aneurysm formation at the repair site after patch angioplasty for coarctation of the aorta.
abstract: OBJECTIVE
  This study used magnetic resonance imaging (MRI) to evaluate the morphology and pathophysiology of aneurysm formation after patch angioplasty for coarctation of the aorta.
  
  
  BACKGROUND
  Late aneurysm formation at the repair site is a well known and frequent complication after patch angioplasty. However, because the underlying mechanisms remain unresolved, postoperative outcome is unpredictable and adequate follow-up difficult.
  
  
  METHODS
  Seventy-three of 85 patients with patch angioplasty for coarctation of the aorta were screened for aneurysm formation. Magnetic resonance imaging was performed in all 33 patients with an aneurysm, and results were compared with those for 13 control patients and 10 normal subjects. Mean (+/- SD) time between operation and MRI was 12.0 +/- 2.0 years. Aneurysm was defined as the ratio of the diameter of the aorta at the repair site to the diaphragmatic aorta > or = 1.5. Hypoplasia of the transverse arch and recoarctation at the repair site were defined as a ratio < 0.9. Transverse arch ratios on MRI were compared with those on preoperative cineangiography and the pressure gradient between the patient's right and left arm.
  
  
  RESULTS
  All 33 patients with an aneurysm had a hypoplastic transverse arch. The 13 patients with a normal ratio at the repair site had a normal transverse arch ratio (chi square, p < 0.0001). Logarithmic regression showed a significant negative correlation (r = 0.62) between the repair site and transverse arch ratios. A significant pressure difference between the patient's right and left arm was found in patients with versus those without aneurysm (p = 0.0009). No significant difference was found between transverse arch ratios on preoperative cineangiography and postoperative MRI (mean 0.014 +/- 0.1, p = 0.4).
  
  
  CONCLUSIONS
  Aneurysm formation at the repair site is highly related to hypoplasia of the transverse arch. Sufficient catch-up growth of a hypoplastic transverse arch is rare after late patch angioplasty. Dynamic phenomena, such as flow acceleration and turbulence, originating in a narrow transverse arch, may contribute to aneurysm formation at the repair site after patch angioplasty.
authors.affiliation: Department of Radiology, University Hospitals, Catholic University of Leuven, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Bogaert
authors.forename: M
authors.initials: M
authors.lastname: Gewillig
authors.forename: F
authors.initials: F
authors.lastname: Rademakers
authors.forename: H
authors.initials: H
authors.lastname: Bosmans
authors.forename: J
authors.initials: J
authors.lastname: Verschakelen
authors.forename: W
authors.initials: W
authors.lastname: Daenen
authors.forename: A L
authors.initials: AL
authors.lastname: Baert
mesh_terms: D000293:Adolescent; D000328:Adult; D017130:Angioplasty / Q000379:methods; D001013:Aorta, Thoracic / Q000002:abnormalities*; D017545:Aortic Aneurysm, Thoracic / Q000209:etiology* / Q000503:physiopathology; D001017:Aortic Coarctation / Q000503:physiopathology / Q000601:surgery*; D015984:Causality; D002648:Child; D002675:Child, Preschool; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D015994:Incidence; D007223:Infant; D018810:Magnetic Resonance Angiography; D008297:Male; D011183:Postoperative Complications / Q000209:etiology*