The bidirectional Glenn operation: a risk factor analysis for morbidity and mortality.

OBJECTIVE: Patients with single ventricle heart defects often undergo a palliative bidirectional Glenn operation. For this operation, we analyzed potential risk factors for morbidity and mortality. We also evaluated the effects of a persistent left superior vena cava by comparing the outcomes of unilateral and bilateral operations.
METHODS: We reviewed the clinical records of 270 consecutive patients who underwent a bidirectional Glenn operation between 2001 and 2007. A total of 226 patients underwent unilateral operations and 44 patients underwent bilateral operations. Patient characteristics included weight and age, single ventricle morphology, vena caval anatomy, and previous surgery. Operative details included cardiopulmonary bypass technique and duration, pulmonary artery management, hemi-Fontan construction, concomitant procedures, and hemodynamics. Outcome data included duration of chest tube drainage, lengths of intensive care unit and hospital stay, morbidity, and mortality (<30 days).
RESULTS: The median length of chest tube drainage was 2.4 days (range 1-20 days). Risk factors for prolonged drainage were elevated central venous pressure (P = .015) and transpulmonary gradient (P = .011). The median lengths of stay in the intensive care unit and hospital were 50 hours (range 20-1628 hours) and 5 days (range 2-83 days), respectively. Risk factors for both included prolonged cardiopulmonary bypass time, elevated central venous pressure and transpulmonary gradient, and right ventricular morphology. Overall, 72 of 270 patients (27%) had 116 postoperative complications. Risk factors included prolonged cardiopulmonary bypass time (P = .002) and elevated central venous pressure (P = .029). Mortality was 2 of 270 patients (0.7%). No risk factors for death were identified. Weight (median 6.8 kg vs 6.2 kg, P = .038) and age (median 186 days vs 159 days, P = .001) at the time of surgery were significantly greater in the bilateral bidirectional Glenn group compared with the unilateral group. However, there was no difference in any of the outcome variables.
CONCLUSION: Outcomes were adversely affected primarily by prolonged cardiopulmonary bypass time, elevated central venous pressure and transpulmonary gradient, and right ventricular morphology. Specifically, outcomes were unaffected by the presence of a left superior vena cava, cannulation strategy, or antegrade pulmonary blood flow. There were few differences between the unilateral and bilateral groups, none of which were postoperative outcomes.