Almost fifty years after its first clinical application, the modified Fontan operation is among the most frequently performed procedures in congenital heart disease surgery in children today. The objective of this review is to systematically summarize the international evolution of outcomes in regard to morbidity and mortality of patients with Fontan palliation. All studies published over the past five decades with more than 100 Fontan patients included were screened. In eligible studies, information concerning preoperative patients' characteristics, Fontan modifications employed, early mortality, long-term survival and frequency of relevant complications was extracted. Ultimately, thirty-one studies published by the largest surgical centers with an overall number of 9390 patients were included in this review. The extracardiac total cavopulmonary anastomosis is the most frequently used Fontan modification. Hemodynamic data demonstrate a rigorous overall adherence to suggested Fontan selection criteria. The analysis showed a clear trend toward improved early and long-term survival over the time period covered. Although inconsistently reported, severe complications such as arrhythmias, thromboembolic events and protein-losing enteropathy as well as reoperations and reinterventions were frequent. In conclusion, patients palliated for complex univentricular heart malformations nowadays benefit from the experience and technical developments of the past decades and have a significantly improved long-term prognosis. However, important issues concerning postoperative long-term morbidity and mortality are still unsolved and clear intrinsic limitations of the Fontan circulation are becoming evident as the population of Fontan patients ages.

Background-The role, interplay, and relative importance of the multifactorial hemodynamic and myocardial mechanisms causing dysfunction of the Fontan circulation remain incompletely understood. Methods and Results-Using an MRI catheterization technique, we performed a differential analysis of pulmonary vascular resistance and aortopulmonary collateral blood flow in conjunction with global ventricular pump function, myocontractility (end-systolic pressure-volume relation), and diastolic compliance (end-diastolic pressure-volume relation) in 10 patients with a Fontan circulation at rest and during dobutamine stress. Pulmonary and ventricular pressures were measured invasively and synchronized with velocity-encoded MRI-derived pulmonary and aortic blood flows and cine MRI-derived ventricular volumes. Pulmonary vascular resistance and end-systolic and end-diastolic pressure-volume relations were then determined. Aortopulmonary collateral flow was calculated as the difference between aortic and pulmonary flow. Compared to rest, dobutamine caused a small increase in mean pulmonary pressures (PϽ0.05). Collateral flow was significantly augmented (PϽ0.001) and contributed importantly to an increase in pulmonary flow (PϽ0.01). Pulmonary vascular resistance decreased significantly (PϽ0.01). Dobutamine did not increase stroke volumes significantly despite slightly enhanced contractility (end-systolic pressure-volume relation). Active early relaxation () was inconspicuous, but the end-diastolic pressure-volume relation shifted upward, indicating reduced compliance. Conclusions-In patients with a Fontan circulation, aortopulmonary collateral flow contributes substantially to enhanced pulmonary flow during stress. Our data indicate that pulmonary vascular response to augmented cardiac output was adequate, but decreased diastolic compliance was identified as an important component of ventricular dysfunction. (Circ Cardiovasc Imaging. 2010;3:623-631.)