RT Book, Section
A1 Kanani, Mazyar
A1 Elliott, Martin J.
A2 Yuh, David D.
A2 Vricella, Luca A.
A2 Yang, Stephen C.
A2 Doty, John R.
SR Print(0)
ID 1104595851
T1 Atrioventricular Septal Defects
T2 Johns Hopkins Textbook of Cardiothoracic Surgery
YR 2014
FD 2014
PB McGraw-Hill Education
PP New York, NY
SN 978-0-07-166350-2
LK accesssurgery.mhmedical.com/content.aspx?aid=1104595851
RD 2024/04/25
AB EpidemiologyThe  prevalence  of  atrioventricular  septal  defect  (AVSD)  is  0.19  per  1000  live  births,  accounting  for  2.9  percent  of  congenital  cardiac  malformations.  In  about  60  percent  of  these  cases,  shunting  is  confined  to  the  atrial  level.  Tetralogy  of  Fallot  (ToF)  is  associated  in  2  to  10  percent  of  cases  of  AVSD,  while  Down  syndrome  is  seen  in  75  percent  of  infants  with  complete  AVSD.MorphologyThis  is  variable,  according  to  extent  and  presence  of  atrial  and  ventricular  components;  however,  a  common  atrioventricular  valve  (AV)  and  displacement  of  the  AV  node  are  common  features.  These  defects  typically  fall  into  three  categories:  (A)  partial  (primum  component  only);  (B)  complete  atrial  septal  defect  (ASD)  and  ventricular  septal  defect  (VSD);  and  (C)  transitional  (restrictive  VSD).  Complete  AVSD  is  further  subdivided  according  to  the  degree  of  bridging  of  the  superior  leaflet.  Although  Rastelli  type  A  is  most  common  (70  percent  of  all  complete  AVSDs),  type  C  is  the  one  most  frequently  associated  with  ToF.PathophysiologyPathophysiology  varies  with  the  degree  of  shunting,  left  ventricular  AV  valve  regurgitation,  and  pulmonary  vascular  resistance,  as  well  as  with  associated  anomalies.Clinical  featuresLarger  left-to-right  shunts  (complete  AVSDs)  will  present  early  in  infancy  with  congestive  heart  failure  and  pulmonary  hypertension,  while  presentation  of  partial  and  transitional  AVSDs  (in  the  absence  of  significant  left  AV  valve  regurgitation)  will  present  later  and  have  a  similar  presentation  and  natural  history  as  ASDs.DiagnosisChest  x-ray  (CXR)  will  disclose  an  enlarged  cardiac  silhouette  and  increased  pulmonary  markings  in  large  shunts.  Echocardiography  is  diagnostic  and  defines  type  of  defect,  valvar  morphology  and  degree  of  regurgitation,  relative  ventricular  balance,  and  associated  anomalies.  Cardiac  catheterization  is  used  in  selected  cases  and  shows  the  characteristic  “gooseneck  deformity”  from  subaortic  elongation  of  the  left  ventricular  outflow  tract  (LVOT).TreatmentA  staged  approach  [pulmonary  artery  banding  (PAB)  followed  by  complete  repair]  is  relegated  to  selected  cases  of  complete  AVSD.  Most  cases  should  be  repaired  before  6  months  of  age,  whereas  partial  defects  without  valvar  regurgitation  and  defects  with  a  restrictive  VSD  component  can  be  repaired  between  2  and  4  years  of  age.OutcomesOperative  mortality  for  complete  AVSDs  is  currently  below  5  percent,  and  incomplete  defects  have  similar  morbidity  and  mortality  as  ASDs.  Long-term  prognosis  is  defined  by  long-term  valvar  completenvy  and  associated  lesions.