Functional state of patients with heterotaxy syndrome following the Fontan operation

Children born with heterotaxy syndromes have poorer outcomes compared with children born with comparable cardiac lesions requiring similar surgical palliation. Heterotaxy has been reported as a separate risk factor for mortality and increased morbidity in a series of Fontan operations reported from single centres. Little is known, however, about the functional state of surviving patients with heterotaxy following a Fontan operation.

In the multicentric cross-sectional study carried out by the Pediatric Heart Network of 546 survivors of the Fontan procedure, the patients, aged from 6 to 18 years, underwent evaluation by echocardiography, exercise testing, electrocardiography, magnetic resonance imaging, and functional health status questionnaires compiled by the patients and their parents. Heterotaxy was identified in 42 patients (8%). Medical and patient characteristics were compared between those with heterotaxy and the remaining 504 patients who did not have heterotaxy.

Patients with heterotaxy had their Fontan procedure performed at a later age, with a median of 3.9 years versus 2.8 years (p=0.001) and had volume-unloading surgery performed later, at a median age of 1.4 versus 0.9 years (p=0.008). These patients had significantly different ventricular and atrioventricular valvar morphology, as well as a higher incidence of systemic and pulmonary venous abnormalities. They had a higher incidence of prior surgery to the pulmonary veins, at 21 versus 0.4%. The type of Fontan procedure was different, but no difference was detected in length of stay in hospital, or the number of postoperative complications. Sinus rhythm was less common, at 44 versus 71%, (p=0.002), and history of atrial arrhythmias more common, at 19 versus 8%, (p=0.018) in those with heterotaxy. Echocardiography revealed a greater degree atrioventricular valvar regurgitation, lower indexed stroke volume, and greater Tei index. Exercise performance, levels of brain natriuretic peptide in the serum, and summary and domain scores from health status questionnaires, were not different from those not having heterotaxy.

The study illustrates a profile of characteristics, medical history, functional health state, and markers of ventricular performance in patients with heterotaxy after the Fontan procedure. Despite obvious anatomic differences, and some differences in echocardiography and heart rhythm, there were no important differences in exercise performance or functional health state between these patients and other survivors of the Fontan procedure.