Evaluation of postoperative pulmonary regurgitation after surgical repair of tetralogy of Fallot: comparison between Doppler echocardiography and MR velocity mapping.

BACKGROUND: Pulmonary regurgitation is a common finding in patients after correction of tetralogy of Fallot (TOF). Right ventricular impairment and even ventricular arrhythmia have been ascribed to pulmonary valve insufficiency (PI), which is therefore an important issue in follow-up examinations.
OBJECTIVE: To compare PI measured by echocardiography (ECHO) with data provided by cardiac MRI (CMR).
MATERIALS AND METHODS: We studied 54 selected patients (18 female; median age 14.0 years, range 3.8-53.4 years) after surgical correction of TOF. To quantify pulmonary regurgitant fraction (PRF) by CMR, flow velocity mapping was performed. On Doppler ECHO, length, width and localization of regurgitant flow was measured. The severity of PI was categorized as mild, moderate or severe and compared to the data obtained by CMR.
RESULTS: On CMR the mean PRF was 29.2 +/- 13.4%. Patients with a transannular patch had a significantly higher PRF (39.9 +/- 11.6%) than patients with an intact annular ring (23.6 +/- 11.4%). Differentiation by Doppler ECHO between the categories mild, moderate and severe PI was confirmed by significant differences in PRF measured by CMR (mild vs. moderate P < 0.04; moderate vs. severe P < 0.014; mild vs. severe P < 0.001). Furthermore, PRF correlated with right ventricular end diastolic volume index (r = 0.45, P < 0.01) and right ventricular end systolic volume index (r = 0.39, P < 0.01).
CONCLUSION: Doppler ECHO can estimate the severity of PI after repair of TOF with acceptable results compared to CMR flow measurement. In univariate analysis there is only a weak influence of PRF on right ventricular volume.