Progressive stiffening and relatively slow growth of the dilated ascending aorta in long-term Fontan survivors-Serial assessment for 15 years

Background: A stiffened, dilated ascending aorta may represent an important predictor of cardiovascular mortality, and has been reported in patients with congenital heart disease, including single ventricle. However, the serial conformational changes and determinants of reduced distensibility in ascending aorta have not been clarified.

Methods: This retrospective study investigated 115 postoperative Fontan survivors (median age at Fontan: 3.7 years). All patients underwent cardiac catheterization before and 1, 5, 10, and 15 years after the Fontan operation. We measured Z-scores for diameters and stiffness indexes (β) of the ascending aorta and descending aorta from angiograms. We also reviewed the clinical profiles, hemodynamic parameters, and exercise capacities of patients and compared them with results from 47 control subjects.

Results: Fontan survivors displayed significantly larger Z-score and β of the ascending aorta from before to 15 years after surgery than controls, whereas values for the descending aorta were comparable. Z-score for the ascending aorta was decreased, but β was elevated significantly according to the trend test. In multivariable analysis, β of the ascending aorta at 15 years after Fontan operation and its increasing trend were associated with older age at Fontan operation and elevated ventricular end-diastolic pressure. Reduced exercise capacity also correlated with stiffening of the ascending aorta.

Conclusions: Fontan survivors showed progressive stiffening and relatively slow growth of the dilated ascending aorta. Progressive stiffening of the ascending aorta may be coupled to diastolic dysfunction and reduced exercise capacity, suggesting the importance of lifelong management of subclinical Fontan pathophysiology.