Background: Preoperative risk analysis for Fontan candidates is still less than optimal in that patients with apparently low risk can have poor surgical outcome-prolonged pleural effusion drainage, protein losing enteropathy, pulmonary thromboembolism and death. We hypothesized that pulmonary vascular compliance is a risk factor to predict surgical outcome in terms of the duration of the pleural effusion drainage. Methods: A retrospective review of 96 consecutive patients who underwent extracardiac Fontan procedure between January 2002 and May 2005 was performed. Patients who had extracardiac Fontan revision after conventional Fontan procedures were excluded from this study. Fontan risk score (FRS) was calculated including 12 preoperative variables. Pulmonary vascular compliance (PVC, mm짼/mmHg/m짼) was defined as pulmonary artery index (mm짼/m짼) divided by pulmonary vascular resistance (W.U쨌m짼) and pulmonary blood flow (L/min/m짼), based on the electrical circuit analogue of the pulmonary circulation. Chest tube indwelling time was log-transformed (Log indwelling time, LIT) to fit normal distribution, and the relationship between preoperative predictors and LIT was analyzed by multiple linear regression. Results: FRS, PVC, Cardiopulmonary bypass time (CPB) upon Fontan operation and central venous pressure at postoperative 12 hours were correlated with LIT by univariable analyses. By multiple linear regression, however, only PVC (p=0.0018) and CPB (p=0.0024) independently predicted the log-transformed indwelling time explaining 21.7% of the variation. The regression equation of LIT was as follows: LIT = 2.74 - 0.0158쨌PVC + 0.00658쨌CPB. Conclusion: Pulmonary vascular compliance is an important risk factor to predict pleural effusion duration after extracardiac Fontan operation.