Left atrial (LA) stiffness is linked to pulmonary congestion and exercise intolerance in patients with acquired form of heart failure but has not been studied in adults with coarctation of aorta (COA). We hypothesized that adults with COA had increased LA stiffness, and in turn, worse cardiac reserve, pulmonary congestion, and impaired aerobic capacity compared to controls, and that LA stiffness index was associated with the presence of these abnormalities in the COA group.

In this prospective study, 46 adults with repaired COA and 46 controls underwent exercise echocardiogram with expired gas analysis. LA stiffness was assessed at rest as the quotient for lateral E/e’ and LA reservoir strain (E/e’/LARS). Cardiac reserve was assessed by exercise-induced change in LA reservoir strain, right ventricular free wall strain/right ventricular systolic pressure (RV-PA coupling), and cardiac output (CO). Pulmonary congestion was assessed by lung ultrasound.

The COA group had higher LA stiffness index (0.47 ± 0.12 vs 0.14 ± 0.09, P < .001), and in turn, worse cardiac reserve, pulmonary congestion, and aerobic capacity compared to controls. Within the COA group, those with high LA stiffness index (>0.42) had worse cardiac reserve, pulmonary congestion, and aerobic capacity. The correlates of LA stiffness index were high pulsatile left ventricular (LV) afterload, LV hypertrophy, and atrial fibrillation.

These data suggest a mechanistic link between LA stiffness, pulmonary congestion, and exercise intolerance among patients with COA, and the correlates of LA stiffness index may provide viable targets for therapeutic interventions to improve outcomes in this population.