Pulmonary vascular compliance and pleural effusion duration after the Fontan procedure.

BACKGROUND: Preoperative risk analysis for Fontan candidates is still less than optimal in that patients with apparently low risks may have a poor outcome, such as prolonged pleural drainage, protein-losing enteropathy, pulmonary thromboembolism and death. We hypothesized that low pulmonary vascular compliance (PVC) is a risk factor for persistent pleural effusion after the Fontan operation.
METHODS: A retrospective review of 85 patients who underwent the extracardiac Fontan procedures (median age: 3.87 years) was performed. Fontan risk score (FRS) was calculated from 12 categorized preoperative anatomical and physiological variables. PVC (mm(2)/m(2) x mmHg) was defined as pulmonary artery index (mm(2)/m(2)) divided by total pulmonary resistance (Wood Unit x m(2)) and pulmonary blood flow (L/min/m(2)), based on the electrical circuit analogy of the pulmonary circulation. Chest tube indwelling time was log-transformed (log indwelling time, LIT) to fit normal distribution, and the relationship between perioperative predictors and LIT was analyzed by multiple linear regression.
RESULTS: Preoperative PVC, chest tube indwelling time and LIT ranged from 6 to 94.8 mm(2)/mmHg/m(2) (median: 24.8), 3 to 268 days (median: 20 days), and 1.1 to 5.6 (mean: 2.9, standard deviation: 0.8), respectively. FRS, PVC, cardiopulmonary bypass time (CPB) and central venous pressure at postoperative 12 h were correlated with LIT by univariable analyses. By multiple linear regression, PVC (p=0.002) and CPB (p=0.003) independently predicted LIT, explaining 22% of the variation. The regression equation was LIT=2.744-0.016 PVC+0.007 CPB.
CONCLUSION: Low pulmonary vascular compliance is an important risk factor for prolonged pleural effusion drainage after the extracardiac Fontan procedure.