Myocardial tissue Doppler assessment of diastolic function in the growth-restricted fetus

Myocardial tissue Doppler (MTD) is a technique for the measurement of myocardial velocities in systole and diastole. This study evaluates the use of MTD in the assessment of cardiac diastolic function in fetuses with intrauterine growth restriction (IUGR) with placental insufficiency and in appropriate-for-gestational age (AGA) fetuses with hypertensive mothers.

This study included 14 IUGR fetuses with placental insufficiency (Group 1), 13 AGA fetuses with hypertensive mothers (Group 2), and 29 AGA fetuses with healthy mothers (Group 3). Patients with other diseases were excluded. All fetuses had a gestational age of at least 25 weeks. MTD assessment was performed with the sample volume placed at the basal segment of the left ventricular side wall (LV), the interventricular septum (IVS) and the right ventricular free wall (RV). E'/A' ratios were calculated for each location. Mitral and tricuspid flows were assessed by conventional spectral pulsed Doppler.

Significant differences were found between groups for E'/A' at the IVS (P < 0.001) and LV (P = 0.009), with a higher mean (+/- SD) value in Group 1 (IVS: 0.92 +/- 0.28; LV: 0.85 +/- 0.19) than in Groups 2 (IVS: 0.62 +/- 0.09; LV: 0.68 +/- 0.14) and 3 (IVS: 0.71 +/- 0.14; LV: 0.69 +/- 0.15). In the RV, there was no statistically significant difference in the E'/A' ratio (P = 0.2). No differences were observed for mitral and tricuspid flow velocities and ratios.

Using MTD, the ratios between early and late diastolic myocardial velocities are higher in IUGR fetuses than in AGA fetuses at the IVS and the LV, regardless of the presence of maternal hypertension. MTD may be more sensitive than atrioventricular spectral Doppler for the detection of ventricular diastolic dysfunction in IUGR fetuses.