P134. Assessment of Pulmonary Regurgitation in Adults with Repaired Tetralogy of Fallot — Comparison Between Doppler-Echocardiography and MRI
OBJECTIVE: To assess severity of pulmonary regurgitation seen in patients with repaired tetralogy of Fallot using Doppler echocardiography and MRI.
METHODS: We studied 50 asymptomatic patients (aged 31± 10 years, 23± 5 years after initial repair, 23 females). Right ventricular end-diastolic dimension was taken from a frozen image of the parasternal view. From the continuous wave Doppler trace, pulmonary regurgitation was classified as mild when pressure drop was maintained during diastole, moderate when equilibration between pulmonary artery and right ventricular pressures occurred in late-diastole and severe when in mid-diastole. The ratio between pulmonary regurgitation duration and total diastole was also measured to assess its severity; a ratio =>85% for mild, 60-85% for moderate and =<60% for severe. Pulmonary regurgitant fraction was assessed using MRI; 0-15% for mild, 15-30% for moderate, and =>30% for severe.
RESULTS: 24 patients were found to have severe regurgitation by the two techniques. Echo confirmed 5/6 patients with moderate regurgitation and the remaining had either no or mild regurgitation by the two techniques (r=0.64, p<0.01). Doppler pulmonary regurgitation duration/diastole ratio correlated with MRI regurgitant fraction (r=-0.71, P=0.005). Echo assessed right ventricular end-diastolic dimension correlated with MRI end-diastolic volume index (r=0.58, P=0.001) and end-systolic volume index (r=0.61, P=0.02).
CONCLUSION: Significant pulmonary regurgitation is commonly seen in asymptomatic patients with repaired tetralogy of Fallot. This and its effects on right ventricular dimensions can equally be assessed by echo and MRI techniques.