All patients who underwent a bidirectional Glenn for treatment of single ventricle physiology at Children’s Hospital, Denver between January 1995 and March 2007 were included in this study. While the modified Fontan procedure results in corrected physiology, the presence of a fenestration incompletely separates the pulmonary and systemic circulations. Accordingly, for the purpose of this study, both the bidirectional Glenn and Fontan procedures are considered palliative operations. A retrospective review of patient records was performed in accordance with a research protocol accepted by the Colorado Multi-Institutional Review Board. Because of the retrospective nature of the study, individual patient consent was waived.
122 patients were identified for this study. The median age at BDG was 6.6 months (range 1.4 months to 6.1 years). Prior palliative procedures were performed in 89 patients (73%). These are outlined in . The remaining 33 patients underwent primary BDG.
Palliative Procedures Performed Before Bidirectional Glenn
Bidirectional Glenn was performed using a median sternotomy and conventional cardiopulmonary bypass techniques. The superior vena cava was transected at the level of the right pulmonary artery (PA) and anastomosed to the superior border of the right pulmonary artery using continuous 7-0 polypropylene suture. As a routine, the main pulmonary artery was ligated at the time of BDG.
The Fontan operation was performed using cardiopulmonary bypass at normothermia. The majority of patients (46/52) underwent an extracardiac Fontan using an 18- or 20-mm ePTFE graft anastomosed to the undersurface of the MPA, offset to the left of the BDG. For patients who underwent a fenestration, a 4- to 5-mm fenestration was created between the Fontan conduit and the common atrial free wall. The remaining 6 patients underwent the lateral tunnel modification of the Fontan operation. A PTFE patch was fashioned in the common atrium to baffle the IVC return to the MPA. Additional patch enlargements of the branch pulmonary arteries were performed when needed.
Specific cardiac diagnoses are summarized in . The functional ventricle was the morphological left ventricle in 90 patients (74%) and the morphological right ventricle in 32 patients (26%).
Distributions of cardiac diagnoses. The functional single ventricle was the LV in 74% and the RV in 26%.
The altitude was recorded at the patient’s place of residence at time of BDG. Mean altitude was 1600±309 m (range, 310 to 2580 m). The altitude distribution is displayed in . Surgical procedures were performed at an altitude of 1604 m at Children’s Hospital, Denver.
Altitude distribution in the study population. Mean altitude was 1600±309 m.
Outcome End Points
Palliation failure (PF) was defined as death, BDG/Fontan takedown, need for cardiac transplantation, or Fontan revision. The marginal (MG) cohort was characterized as patients who demonstrated failure to thrive because of recurrent pleural effusions, persistent hypoxemia, multiple hospital admissions, or hemodynamic contraindications to proceed to Fontan completion.
Cardiac catheterization was performed to determine patient eligibility for cavopulmonary palliation by measurement of pulmonary arterial pressure (PAP), indexed pulmonary vascular resistance (PVRI), ventricular end-diastolic pressure (VEDP), transpulmonary gradient (TPG), atrioventricular valve function, and adequacy of pulmonary arterial anatomy. Catheterization data reported are those under baseline conditions.
Functional assessment of exercise tolerance was based on guidelines for New York Heart Association (NYHA) classification. Follow-up information was obtained from the most recent patient assessment by the pediatric cardiologist or referring pediatrician at a mean period of 3.4 years (range, 3 months to 10.7 years). Follow-up was complete in 97% of patients, with 4 of 122 patients lost to follow-up.
Statistical analysis was performed with Prism version 5.0 (Graphpad Inc). Continuous data are described as median with ranges or mean with standard deviation and analyzed by the 2-tailed Student t test. Survival and freedom from reoperation was determined by Kaplan–Meier methodology, and statistical differences were analyzed using the log-rank test. Probability values less than 0.05 were considered statistically significant.
Statement of Responsibility
The authors had full access to and take full responsibility for the integrity of the data. All authors have read and agree to the manuscript as written.