Pulmonary Vascular Disease in the Single-Ventricle Patient: Is it Really Pulmonary Hypertension and if So, How and When Should We Treat it?

Despite significant improvements in the surgical and postoperative care for patients with single-ventricle physiology culminating in the Fontan circulation, significant late morbidity and mortality remains. In the setting of passive (ie, non-“pump” driven) pulmonary blood flow, pulmonary vascular resistance (PVR) plays a key role in determining cardiac output, and even slight elevations in PVR may result in significant morbidity. There is now great interest to treat Fontan patients with pulmonary vasodilators in an attempt to “optimize” PVR (and by extension, quality of life) and/or improve an elevated PVR. This review discusses the hemodynamic implications of the Fontan circulation, the evidence for use of pulmonary vasodilator therapy, and possible target physiologic mechanisms.