The modified Fontan operation for asplenia and polysplenia syndromes.

From 1975 through 1986, 49 patients with asplenia (23 patients) or polysplenia (26 patients) syndromes underwent a modified Fontan operation. All patients had anomalous systemic venous return, and 43 (88%) had anomalous pulmonary venous return. The atrioventricular valve anatomy varied: 36 patients had a common atrial chamber and common atrioventricular valve, eight had mitral valve atresia, and five had severe mitral valve hypoplasia. Redirection of systemic venous return was accomplished by (1) atrial baffle (29 patients), (2) intraatrial conduit (19 patients), and (3) extraatrial conduit (one patient). There were 21 (43%) hospital deaths overall. However, since 1985, six of 22 patients (27%) have died. Increased mortality was seen in patients requiring atrioventricular valve repair or replacement (8/11, 73%) and in patients with asplenia (65%). Lower mortality was seen in patients with polysplenia (24%) and those receiving an intraatrial conduit (26%), although this decrease also represents the more recent experience. We conclude: (1) The Fontan operation for patients with asplenia or polysplenia syndromes has resulted in a significant (although recently declining) mortality; (2) mortality is higher in patients with asplenia; (3) patients with atrioventricular valve insufficiency requiring repair or replacement are at higher risk; and (4) intraatrial conduits seem to offer promise for successfully accomplishing this repair.