Intracardiac Doppler assessment of left valve inflow in first-trimester fetuses with increased nuchal translucency: preliminary observations in trisomy 21.

OBJECTIVES

To perform a qualitative assessment of the pulsed Doppler waveform profile at the level of left atrioventricular valve inflow in first-trimester fetuses with increased nuchal translucency thickness (NT), in order to compare those with trisomy 21 and those with normal karyotype.

METHODS

This was a review of 285 consecutive fetuses with increased NT. Pulsed Doppler velocity waveforms of left atrioventricular valve inflow were recorded. The E-wave, A-wave and velocity profile in the aorta were displayed. Cases were classified into two patterns: Pattern A included those in which the E-wave velocity crossed the A-wave before the baseline in all waveforms; Pattern B included those in which the lowest E-wave velocity crossed the baseline but not the A-wave in at least one of the profiles. The karyotype was determined and the frequency of occurrence of Patterns A or B in fetuses with normal karyotype and those with trisomy 21 were compared.

RESULTS

Of the 285 cases, 230 were assigned to Pattern A and 55 to Pattern B. There were 47 cases of trisomy 21, 22 had other chromosomal abnormalities, and 212 had a normal karyotype; in four cases the karyotype was unknown. Among the 212 karyotypically normal fetuses, five had heart defects, five had other structural defects, three suffered spontaneous intrauterine death and one was terminated. Pattern A was found in 200/212 (94.3%) cases with normal karyotype, in 12/47 (25.5%) cases with trisomy 21, and in 17/22 (77.3%) cases with other chromosomal abnormalities. Pattern B was found in 12/212 (5.7%) cases with normal karyotype, in 35/47 (74.5%) cases with trisomy 21 (chi-square test, P < 0.001), and in 5/22 (22.7%) cases with other chromosomal abnormalities.

CONCLUSIONS

Intracardiac Doppler qualitative assessment of left valve inflow in first-trimester fetuses with increased NT shows differences between normal and trisomy 21 fetuses, probably reflecting differences in myocardial function.