title: Restrictive left atrial outflow adversely affects outcome after the modified Norwood procedure.
abstract: OBJECTIVE
  Moderate restrictive foramen ovale in neonates with hypoplastic left heart syndrome (HLHS) is considered to be favourable, reducing pulmonary overcirculation, before modified Norwood operation. However, some newborns with severe restriction of interatrial communication will have pulmonary vascular disease at birth, which correlates with increased perioperative mortality. This article studies the post-Norwood hemodynamic patterns and outcome for the particular group of HLHS newborns with restrictive left atrial outflow compared to other patients.
  
  
  METHODS
  Restrictive left atrial outflow is defined as mitral and/or aortic atresia with intact ventricular septum, and restrictive foramen ovale, with 3 mm diameter or less with mean interatrial pressure gradient more than 5 mmHg at preoperative echo-Doppler. Four neonates fulfilled these criteriae among 18 consecutive patients, who underwent Norwood procedure from October 2002 to December 2003. Mean arterial pressure, heart rate, mean common atrial pressure, urinary output, central venous and arterial oximetry data, serum lactate levels, and dosages of milrinone, phentolamine and norepinephrine were collected at 0, 6, 12, 18 and 24 h after operation. Data were summarized as mean+/-SEM. For univariate comparison of different variables, Student's t-test was used.
  
  
  RESULTS
  The postoperative hemodynamic pattern of patients with restrictive left atrial outflow was characterized by hypoxemia and low cardiac output. Arterial (66+/-3.0% vs 76+/-1.0%, P=0.01) and central venous (37+/-1.2 vs 52+/-1.1%, P=0.001) oxygen saturations were much lower than in patients without restriction. Arterio-venous oxygen saturation difference was wider (29+/-2.4% vs 23+/-0.9%, P=0.02) and serum lactate levels were higher (10.8+/-3.0 vs 2.8+/-0.2 mmol/l, P=0.03). Common atrial pressures were more elevated (12+/-0.8 vs 8+/-0.3 mmHg, P<0.001) and higher norepinephrine doses were needed (0.44+/-0.15 vs 0.06+/-0.01 microg/kg/min, P=0.03). The difference for the mean arterial pressures did not reach the significance level (48+/-2.0 vs 51+/-2.0 mmHg, P=0.2). Operative mortality was higher 75% (3/4) compared to 14.3% (2/14, P=0.04) for the other patients.
  
  
  CONCLUSIONS
  Restrictive left atrial outflow adversely affects outcome after modified Norwood procedure. Abnormal pulmonary vasculature leading to insufficient pulmonary perfusion is incriminated. To improve outcome, implantation of larger size modified Blalock-Taussig or right ventricle-to-pulmonary artery shunts and routine use of postoperative mechanical assist device should be considered.
authors.affiliation: German Paediatric Heart Centre, Deutsches Kinderherzzentrum, Arnold Janssen-Strasse 29, 53757 Sankt Augustin, Germany. photiadis@gmx.de
authors.forename: Joachim
authors.initials: J
authors.lastname: Photiadis
authors.forename: Andreas E
authors.initials: AE
authors.lastname: Urban
authors.forename: Nicodème
authors.initials: N
authors.lastname: Sinzobahamvya
authors.forename: Christoph
authors.initials: C
authors.lastname: Fink
authors.forename: Ehrenfried
authors.initials: E
authors.lastname: Schindler
authors.forename: Martin
authors.initials: M
authors.lastname: Schneider
authors.forename: Anne
authors.initials: A
authors.lastname: Marie Brecher
authors.forename: Boulos
authors.initials: B
authors.lastname: Asfour
mesh_terms: D001021:Aortic Valve / Q000002:abnormalities; D016009:Chi-Square Distribution; D006344:Heart Septal Defects, Atrial / Q000097:blood / Q000503:physiopathology / Q000601:surgery*; D006439:Hemodynamics; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000097:blood / Q000503:physiopathology / Q000601:surgery*; D007231:Infant, Newborn; D019344:Lactic Acid / Q000097:blood; D008943:Mitral Valve / Q000002:abnormalities; D009638:Norepinephrine / Q000627:therapeutic use; D010100:Oxygen / Q000097:blood; D011182:Postoperative Care; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D019344:Lactic Acid; D010100:Oxygen; D009638:Norepinephrine