Utility of Doppler Echocardiography to Estimate the Severity of Pulmonary Valve Regurgitation Fraction in Patients with Repaired Tetralogy of Fallot.

Abstract

In patients with repaired Tetralogy of Fallot (rTOF), pulmonary regurgitation (PR) leads to significant morbidity. Cardiac magnetic resonance imaging (CMR) is the gold standard to assess severity of PR in rTOF patients. We compared Doppler echocardiography derived indices of PR with CMR to find the best predictive parameter for hemodynamically significant (hs) PR. This is a retrospective analysis of echocardiogram and CMR measurements. Doppler indices obtained included: PR deceleration slope, pressure half time (PHT) and PR index. Receiver operating characteristic curve analysis was used to optimize the sensitivity and specificity of selected variables in predicting hsPR. Inter-observer variability of the Doppler parameters was assessed in a random sample of 25 Doppler spectral recordings. Our cohort (n = 96) comprised of 52 (54.2%) males. The mean (SD) age at CMR was 22.9 (10.3) years. 83.4% patients underwent complete repair with transannular patch. 78 (81%) patients had hsPR as defined by CMR PR > 20%. Doppler parameters with the values of; PR index of < 0.86, PR deceleration slope of > 375cm/s2 and a PHT < 130ms, demonstrated high sensitivity (93%) and high negative predictive values (98-99%). All the Doppler indices demonstrated minimal inter-observer variability (PHT = 0.9, 95% CI 0.69-0.97; PRi = 0.95, 95%CI 0.83-0.98). Our data, with its high negative predictive values, show that Doppler derived echocardiography indices have an ability to rule out hsPR, as measured by CMR. PHT, PR index and deceleration slope correlate with hsPR and can be used as screening tools for further testing.