INFLUENCE OF AGE ON THE EFFECT OF BIDIRECTIONAL CAVOPULMONARY ANASTOMOSIS ON LEFT-VENTRICULAR VOLUME, MASS AND EJECTION FRACTION

Objectives. We sought to identify age related differences in the ventr icular response of patients after bidirectional cavopulmonary anastomo sis (CPA) and to compare changes in the ventricular response among chi ldren <3 years of age who underwent CPA with that of age-matched contr ol subjects who had a systemic to pulmonary artery shunt alone, Backgr ound. Pre-Fontan CPA has;been advocated over a systemic to pulmonary a rtery shunt alone in patients with a single ventricle to facilitate ve ntricular volume unloading and minimize risk of the Fontan operation. Methods. Our study evaluated 23 patients who initially received a syst emic to pulmonary artery shunt as an initial procedure before subseque nt Fontan palliation. In eight of these patients (group I), bidirectio nal CPA was performed before age 3 years, and in four (group II), it,v as performed after age 10 years. The remaining 11 patients (group III, age and weight control group for group I) were maintained with their initial shunt until they underwent Fontan palliation. Serial echocardi ographic analysis was used retrospectively to evaluate left ventricula r volume and mass and systolic pump function (ejection fraction) befor e and after bidirectional CPA, Results. Through 10 months of follow-up , group I patients showed significant decreases in indexed end-diastol ic volume both after CPA (120 ml/m(1.5) body surface area vs, 78 ml/m( 1.5), p = 0.001) and in comparison with values in patients in groups I I and III, who showed no changes in end diastolic volume (p < 0.001). Indexed ventricular mass decreased moderately after bidirectional CPA in group I (from 228 g/m(1.5) body surface area to 148 g/m(1.5)) but r emained unchanged in groups II and III, The differences in trends betw een groups I and III were significant (p = 0.03). Ejection fraction de creased significantly in group II versus group I patients (0.48 to 0.2 7 vs. 0.51 to 0.52, p < 0.05) after CPA. Oxygen saturation measurement s before and after bidirectional CPA revealed a significant increase i n group I (73% to 86%, p < 0.001) and a decrease in group II (82% to 7 3%, p < 0.01). Conclusions. Bidirectional CPA facilitates ventricular volume unloading and promotes regression of left ventricular mass in y ounger children (<3 years) in preparation for a Fontan operation. In c ontrast, bidirectional CPA is of questionable value in older children as a staging procedure for Fontan palliation.