title: Hypoplastic aortic arch morphology pertinent to growth after surgical correction of aortic coarctation.
abstract: BACKGROUND
  Whether a hypoplastic transverse arch will grow after successful coarctectomy remains controversial.
  
  
  METHODS
  We studied 15 coarctation specimens with hypoplastic transverse arch. Eight patients were less than 1 month old and 7 were between 1 and 3 months. The diameter and length of the various segments of the aortic arch were measured. The number of elastin lamellae was determined histologically. Collagen density was quantified with a microdensitophotometer. Using immunohistochemistry, we determined alpha-actin-positive smooth muscle cells in the media of the ascending aorta and the hypoplastic transverse arch.
  
  
  RESULTS
  Despite a hypoplastic transverse arch, the ascending and descending aorta grew. The absolute number of elastin lamellae in the hypoplastic transverse arch was low, but when expressed as a ratio versus its diameter, this number was high (p < 0.05). Collagen density showed high absolute values in the descending aorta. In the older group, 4 of 7 showed no staining for alpha-actin in the hypoplastic transverse arch, whereas under 1 month of age, only 2 of 8 cases were negative.
  
  
  CONCLUSIONS
  The hypoplastic transverse arch is characterized by a relatively high number of elastin lamellae. Fewer alpha-actin-positive cells in the hypoplastic transverse arch occur in older specimens, which could indicate a diminished potential growth.
authors.affiliation: Department of Cardiovascular Pathology, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Machii
authors.forename: A E
authors.initials: AE
authors.lastname: Becker
mesh_terms: D000199:Actins / Q000032:analysis; D001013:Aorta, Thoracic / Q000002:abnormalities / Q000254:growth & development* / Q000378:metabolism / Q000601:surgery; D001017:Aortic Coarctation / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D003094:Collagen / Q000032:analysis; D004549:Elastin / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D008297:Male
chemical_list: D000199:Actins; D003094:Collagen; D004549:Elastin