Abstract 2203: Non-invasive Assessment of Pre-Fontan Patients Using Cardiac Magnetic Resonance Imaging Predicts Length of Stay Following Fontan Completion
Introduction Pts frequently undergo cardiac cath prior to Fontan operation due to limited echo windows in the region of the superior cavopulmonary connection (SCPC) and branch pulmonary arteries (BPA). Cardiac MRI (CMR) has unlimited imaging windows and can quantify the net BPA flow.
Hypothesis CMR data impacts surgical technique and outcome.
Methods We retrospectively reviewed 25 CMRs of pts (2.7 yrs, range of 1.3 to 4.0 yrs) referred prior to Fontan. CMR measured the cross-sectional area and flow across the SCPC and BPA. All pre-Fontan echo and cath data were reviewed. Length of stay post-Fontan was acquired from the medical record.
Results CMR identified narrowing of the SCPC or the BPA in 10 of 15 pts who subsequently underwent Fontan. CMR demonstrated moderate correlation (r = 0.69) between the BPA cross-sectional area and the net flow. In 8 of these 10 pts, CMR findings were addressed at surgery with an extended incision or homograft augmentation along the BPA. Echo could not assess either the SCPC or the BPA in 15 pts, and incorrectly remarked that a BPA was normal in five instances. Prolonged length of stay post-Fontan was observed among pts with <40% flow to one BPA (11.9 +/− 5.8 days vs. 7.5 +/− 1.7 days, p = 0.043) or with one BPA that is <25% of the total cross-sectional area (18.7 +/− 4.0 days vs. 8.4 +/− 2.8 days, p = 0.038). There is moderate correlation between the total BPA area and length of stay (r = −0.65). 10 of the 25 pts underwent diagnostic cardiac cath which did not reveal any new findings changing the patient’s clinical course.
Conclusions CMR non-invasively assesses the SCPC and BPA prior to Fontan. This data predicts which pts are more likely to experience a prolonged hospital course.