title: In search of the ideal pulmonary blood source for the Norwood procedure: a meta-analysis and systematic review.
abstract: BACKGROUND
  A clear consensus regarding the optimal source of pulmonary blood flow in patients with hypoplastic left heart syndrome undergoing the Norwood procedure is lacking.
  
  
  METHODS
  A literature search was undertaken to identify relevant articles from 2005 to 2012 using "Norwood, stage 1 palliation," "Modified Blalock Taussig shunt (MBTS)," "right ventricle-to-pulmonary artery shunt (RV-PAS)" alone or in combination. Three end points were selected: early/stage 1 mortality, interstage mortality, and interstage total/shunt intervention.
  
  
  RESULTS
  A total of 20 articles, including 19 observational studies and 1 randomized trial (MBTS, n=1,343; RV-PAS, n=1,028), met the inclusion criteria. Mortality after stage 1 was 22% in the MBTS cohort and 16% in RV-PAS cohort. A pooled analysis showed no difference in early mortality between the two groups (risk ratio [RR], 1.20; 95% confidence interval [CI], 0.99 to 1.45; p=0.07). On pooling data from contemporary series (similar era) of 8 studies (MBTS, n=709; RV-PAS, n=631), to minimize variability in surgical and postoperative management practices, early mortality in both cohorts was comparable (RR, 1.14; 95% CI, 0.89 to 1.45; p=0.29). Interstage mortality was 13.8% and 4.6% in the MBTS and RV-PAS cohorts, respectively, and was significantly lower for RV-PAS (RR, 2.85; 95% CI, 1.65 to 4.89; p<0.00002). However, patients with MBTS had fewer shunt interventions (RR, 0.55; 95% CI, 0.44 to 0.68; p<0.001; I2=00%).
  
  
  CONCLUSIONS
  Our pooled analysis demonstrated no survival benefit for the MBTS or RV-PAS in patients undergoing the Norwood procedure. There appears to be an advantage with the RV-PAS with regard to interstage mortality at the cost of an increased rate of shunt intervention.
authors.affiliation: Division of Surgery, Wellspan York Hospital, York, Pennsylvania.
authors.forename: Vikas
authors.initials: V
authors.lastname: Sharma
authors.affiliation: Cardiovascular Surgery, Adventist Wockhardt Heart Hospital, Surat, Gujarat, India.
authors.forename: Salil V
authors.initials: SV
authors.lastname: Deo
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota.
authors.forename: Marianne
authors.initials: M
authors.lastname: Huebner
authors.affiliation: Division of Cardiothoracic Surgery, Mayo Clinic, Rochester, Minnesota.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Dearani
authors.affiliation: Division of Cardiac Surgery, University of Oklahoma Children's Hospital, Oklahoma City, Oklahoma. Electronic address: burkhart.harold@gmail.com.
authors.forename: Harold M
authors.initials: HM
authors.lastname: Burkhart
mesh_terms: D014943:Global Health; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000401:mortality / Q000503:physiopathology / Q000601:surgery; D058327:Norwood Procedures / Q000379:methods*; D011651:Pulmonary Artery / Q000503:physiopathology / Q000601:surgery*; D011652:Pulmonary Circulation / Q000502:physiology*; D012039:Regional Blood Flow; D015996:Survival Rate; D016896:Treatment Outcome