CONVERSION OF MODIFIED FONTAN PROCEDURE TO LATERAL ATRIAL TUNNEL CAVOPULMONARY ANASTOMOSIS

After modified Fontan procedures with atriopulmonary anastomoses or ri ght atrium-right ventricle conduits, some patients have progressive ex ercise intolerance, effusions, arrhythmias, or protein-losing enteropa thy. Theoretic advantages of a lateral atrial tunnel cavopulmonary ana stomosis and published clinical results suggest that conversion of oth er Fontan procedures to the lateral atrial tunnel may afford clinical improvement for some patients, Eight patients (8 to 25 years old) with tricuspid atresia (n = 4), double-inlet left ventricle (n = 3), and d ouble-outlet right ventricle (n = 1) underwent conversion to a lateral tunnel procedure between December 1990 and November 1994, An arbitrar y clinical score was assigned before the lateral tunnel procedure and at follow-up, Before conversion, patients had decreased exercise toler ance (n = 8), arrhythmias (n = 6), effusions (n = 4), and protein-losi ng enteropathy (n = 8), At catheterization, all had a low cardiac inde x (1.9 +/- 0.7 L . min(-1) . m(-2)), five had elevated pulmonary vascu lar resistance (>3 Wood units), and three had right pulmonary venous r eturn obstruction by compression of an enlarged right atrium, Fenestra ted lateral tunnel construction was undertaken 7.3 +/- 3.6 years after atriopulmonary anastomosis, with one early death related to low cardi ac output. After the lateral tunnel procedure, two patients had no cli nical improvement (no change in clinical score) but five patients had either marked or partial improvement, The right pulmonary vein compres sion present in three patients was resolved after conversion, The mean clinical scores improved from 4.5 +/- 1 to 3.0 +/- 2 (p < 0.04), In c onclusion, conversion to a lateral tunnel procedure led to clinical im provement in five of,eight patients at short-term follow-up and may be particularly indicated for patients with giant right atria or pulmona ry vein compression who have symptoms, Pulmonary vein compression shou ld be looked for in patients after modified Fontan procedures and can be relieved by conversion to the lateral tunnel procedure.