Modified Fontan operation in functionally univentricular hearts: preoperative risk factors and intermediate results

The modified Fontan operation has been proposed as definitive palliation for an increasing variety of hearts with complex univentricular anatomy. To eliminate the influence of different surgical strategies, only patients undergoing total cavopulmonary anastomosis were included in this retrospective study.

Seventy-two patients had been operated on at ages ranging from 7 to 219 months, with 29 patients younger than 4 years. Twenty-three patients had mean pulmonary artery pressures higher than 15 mm Hg, elevated pulmonary arteriolar resistances (> 3 U.m2), or elevated end-diastolic ventricular pressure (> 12 mm Hg). Associated systemic or pulmonary venous anomalies were present in 22 patients (30%), and atrioventricular valve incompetence was present in 21 patients (29%).

The overall mortality rate was 9.7% (7/72). Variables with significant effects on postoperative mortality were associated systemic or pulmonary venous anomalies, atrioventricular valve incompetence, mean pulmonary artery pressure greater than 15 mm Hg, and prolonged cardiopulmonary bypass time. Postoperative morbidity resulted mainly from atrial arrhythmia (20%). Clinical signs of protein-losing enteropathy or atrial thrombi were rare (3% and 6%, respectively). Postoperative hemodynamic data from 48 surviving patients (74%) revealed a mean transpulmonary gradient of 6.3 mm Hg, systemic venous pressure greater than 12 mm Hg in only 10 patients, and cardiac index less than 3 L.min-1.m-2 in 18 patients.

In a high proportion of hearts with complex univentricular anatomy, associated anomalies, and borderline hemodynamics, the Fontan operation can be performed as a total cavopulmonary anastomosis with acceptable intermediate postoperative morbidity and hemodynamic results.