Use of the mitral valve–tricuspid valve distance as a marker of fetal endocardial cushion defects

Objective The purpose of this study was to compare the mitral valve–tricuspid valve distance in second-trimester fetuses with normal cardiac anatomy versus those fetuses with endocardial cushion defects. Study design We identified fetuses between 16 and 24 weeks of gestation. The distance between the insertions of the medial leaflets of the mitral and tricuspid valves were obtained. Linear regression curves were generated. Results The mean mitral valve–tricuspid valve distance for 86 fetuses with normal cardiac anatomy was 2.02 mm, compared with 0.37 mm in 13 fetuses with endocardial cushion defects (P = .0001). Linear regression curve correlating mitral valve–tricuspid valve distance with gestational age showed a gradual slope (R2 = 0.28; P< .0001). With a mitral valve–tricuspid valve distance <5th percentile as a marker for the diagnosis of endocardial cushion defect gave a sensitivity of 69.2%, a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 95.6%, and a false-positive rate of 0% (P = .0001). Conclusion The mitral valve–tricuspid valve distance is useful clinically in the detection of endocardial cushion defects in second-trimester fetuses.