Predictors of outcome after the Fontan operation: is hypoplastic left heart syndrome still a risk factor?

OBJECTIVE This study was undertaken to evaluate factors contributing to a decrease in early mortality and morbidity after the Fontan procedure between January 1, 1992, and December 31, 1999. METHODS Outcomes evaluated were early survival, duration of pleural effusions, and duration of hospitalization. Potential predictors evaluated included anatomic diagnosis, presence of a common atrioventricular valve, preoperative pulmonary artery pressure, type of Fontan operation, type of intentional right-to-left shunt or baffle fenestration, and use of modified ultrafiltration. RESULTS The modified Fontan procedure was performed in 332 patients at a median age of 22 months (range, 11-380 months) and a median weight of 11 kg (range, 5.8-120 kg). Prior stage I reconstructive surgery for classic or variant hypoplastic left heart syndrome had been performed in 205 (53%) of 332 patients, and 318 (96%) had undergone an interim superior cavopulmonary connection. A lateral-tunnel Fontan operation was performed in 281 patients, and an extracardiac conduit Fontan operation was performed in 51 patients. An intentional right-to-left shunt was created in 298 (90%) patients. Between 1992 and 1999, the outcome after the modified Fontan operation improved significantly. Overall mortality was 6.6% (22/332), with only 2 deaths since 1994. Morbidity was also reduced, with a decreased duration of pleural effusions and decreased hospital stay. In a multivariable analysis of the entire cohort, only the presence of a common atrioventricular valve (odds ratio, 7.64; 95% confidence limits, 2.07-28.14; P =.0002) and increased preoperative pulmonary artery pressure (odds ratio, 1.46/1 mm Hg increase; 95% confidence limits, 1.2-1.78; P <.001) increased the risk of early death, whereas use of a single-punch fenestration in a lateral-tunnel Fontan (odds ratio, 0.06; 95% confidence limits, 0.01-0.65; P =.02) and use of modified ultrafiltration (odds ratio, 0.14; 95% confidence limits, 0.03-0.72; P =.019) decreased the risk of death. The risk of prolonged pleural effusions (>3 days) was increased in patients with hypoplastic left heart syndrome (odds ratio, 1.73; 95% confidence limits, 1.07-2.81; P =.03) and was decreased by use of a single-punch fenestration in a lateral-tunnel Fontan operation (odds ratio, 0.17; 95% confidence limits, 0.07-0.4; P <.001), as well as by the use of modified ultrafiltration (odds ratio, 0.25; 95% confidence limits, 0.15-0.40; P <.01). CONCLUSIONS In a contemporary series of Fontan operations performed largely in patients with hypoplastic left heart syndrome or variants, systemic ventricle morphology had no effect on mortality. Some patient characteristics, however, continue to influence outcome. The decrease in mortality and morbidity in the current era is attributed to changes in management strategies, specifically the use of modified ultrafiltration and baffle fenestration.