Saline Contrast Transesophageal Echocardiography in Fontan Patients: Assessment of the Presence, Type, and Size of Right to Left Shunts.

Right to left (R-L) shunts resulting in cyanosis or systemic embolization occur after the Fontan procedure. The primary modality of diagnosing these is angiography. Successful delineation of these shunts in Fontan patients using selective saline contrast transesophageal echocardiography (SCTEE) may allow for reduced radiation and contrast exposure. We hypothesized that SCTEE could accurately determine the presence, type, and semiquantitative shunt size of R-L shunts in Fontan patients. SCTEE was performed in Fontan patients undergoing angiography for clinical indications. Injections were performed in six sites: mid-Fontan, right and left pulmonary arteries, superior and inferior vena cavae, and innominate vein. R-L shunt size was subjectively graded as 0 = absent, 1 = small, and 2 = medium or large based on echo contrast density in the left atrium. SCTEE was compared to angiography. 33 patients with Fontan were studied with median age 15 years, median weight 50.1 kg, and median O2 saturation of 90% in the R-L shunt group and 95% in the no R-L shunt group. R-L shunt types included intracardiac shunts (ICS), veno-venous collaterals (VVCs), arteriovenous malformations (AVMs), and their combinations. SCTEE versus angiography results were the same for the presence, type, and size of R-L shunts in 79% (26/33). SCTEE identified shunts in 88% (29/33). Angiography identified shunts in 85% (28/33). Neither method missed any medium or large R-L shunts. SCTEE and angiography had similar accuracy. SCTEE accurately detected the presence, type, and size of R-L shunts in most Fontan patients in this study. This can be used to guide targeted angiography, reducing radiation exposure and contrast load.