Relationship between N-terminal B-type natriuretic propeptide and right ventricular performance assessed by tissue Doppler imaging and speckle tracking echocardiography in children after surgical repair of tetralogy of Fallot

Background and aim: The relationship between plasma levels of N-terminal B-type natriuretic propeptide (NT-proBNP) and parameters of right ventricular (RV) function was evaluated in patients after surgical repair of tetralogy of Fallot (ToF). Methods: 52 children comprised the study group (SG). The control group (CG) included 32 healthy children. Patient histories, measured NT-proBNP levels and transthoracic echocardiography parameters were analysed. Results: Tissue Doppler imaging (TDI) demonstrated significant differences (p < 0.01) between SG and CG in regard to the following systolic and diastolic function parameters: peak systolic myocardial velocity (S', 5.9 +/- 1.6 cm/s vs. 9.8 +/- 2.3 cm/s), peak early diastolic velocity (E', 6.6 +/- 2.9 cm/s vs. 11.6 +/- 3.1 cm/s), and peak atrial diastolic velocity (A', 3.8 +/- 1.6 cm/s vs. 6.6 +/- 2.8 cm/s). Mean values of peak longitudinal strain (e) were significantly higher (p < 0.01) in SG compared to CG, including basal lateral segment (BL, -32.8 +/- 12.1% vs. -51.5 +/- 15.5%), medial lateral segment (ML, -23.8 +/- 9.5% vs. -40.4 +/- 14.9%), and apical lateral segment (AL, -16.9 +/- 7.5% vs. -35.8 +/- 13.43%). Mean plasma NT-proBNP level also differed significantly (p < 0.01) between SG and CG (286.0 +/- 269.2 pg/mL vs. 153.1 +/- 170.5 pg/mL, respectively). NT-proBNP levels were significantly higher (p < 0.01) in SG subjects with reduced effort tolerance (639.2 +/- 357.1 pg/mL) compared to those with normal effort tolerance (181.8 +/- 97.2 pg/mL), and in patients in whom a transannular patch was used for surgical correction (488.9 +/- 317.19 pg/mL) compared to those treated without the use of a transannular patch (228.1 +/- 217.5 pg/mL). Significant correlations between plasma NT-proBNP level and S' (r = -0.40, p < 0.01), E' (r = -0.50, p < 0.01), BL e (r = 0.36, p < 0.05), and AL e (r = 0.35, p < 0.05) were found. Conclusions: 1. Increased plasma NT-proBNP levels in patients after surgical repair of ToF are related to RV systolic dysfunction, as determined by the S' wave velocity of the tricuspid annulus and longitudinal strain of the RV. 2. Children after surgical repair of ToF showed increased plasma NT-proBNP levels associated with RV diastolic dysfunction as evaluated by TDI.