Nomograms of Fetal Right Ventricular Fractional Area Change by 2D Echocardiography

Abstract

Objectives: Fetal right ventricular (RV) function assessment is challenging due to the RV geometry and limitations of in utero assessment. Postnatally, 2D echocardiographic RV fractional area change (FAC) is used to assess RV global systolic function by calculating the percentage of change in RV area from systole to diastole. Reports on FAC are scarce in prenatal life, and nomograms throughout pregnancy are not available. Our aims were (1) to study prenatal RV FAC feasibility and reproducibility and (2) to construct nomograms for RV FAC and end-diastolic (ED) and end-systolic (ES) RV areas from 18 to 41 weeks of gestation. Methods: Prospective cohort study including 602 low-risk singleton pregnancies undergoing a fetal echocardiography from 18 to 41 weeks of gestation. RV ED and ES areas were measured following standard recommendations for ventricular dimensions and establishing strict landmarks to identify the different phases of the cardiac cycle. RV FAC was calculated as: ([ED area -ES area]/ED area) × 100. RV FAC intra-and inter-observer reproducibility was evaluated in 45 fetuses by calculating the intraclass correlation coefficient (ICC). Parametric regressions were tested to model each parameter against gestational age (GA) and estimated fetal weight (EFW). Results: RV areas and FAC were successfully obtained in ∼99% of fetuses with acceptable reproducibility throughout gestation (RV ED area inter-observer ICC [95% CI] 0.96 [0.93-0.98], RV ES area 0.97 [0.94-0.98], and FAC 0.69 [0.44-0.83]). Nomograms were constructed for RV ED and ES areas and FAC. RV areas showed a quadratic and logarithmic increase with GA and EFW, respectively. In contrast, RV FAC showed a slight quadratic decrease throughout gestation (mean RV FAC ranged from 36% at 18 weeks of gestation [10-90th centiles: 25-47%, respectively] to 29% at 41 weeks [10-90th centiles: 18-40%, Guirado et al. respectively]). The best models for RV areas and FAC were a second-degree polynomial. Conclusions: RV FAC is a feasible and reproducible parameter to assess RV global systolic function in fetal life. We provide reference ranges adjusted by GA and EFW that can be used as normal references for the assessment of RV function in prenatal conditions.

Feasibility of 4D-Spatio Temporal Image Correlation (STIC) in the Comprehensive Assessment of the Fetal Heart Using FetalHQ®

“…We hypothesize that manual adjustment applied for improving the delineation of both ventricles, especially the RV, led to differences in the endocardial delineation, in particular variations of transverse diameters that compute for the SI and FS segmental analysis. In our study, we performed a manual adjustment of the semi-automatic tracking of both ventricles in most of our cases, especially for the RV, considering the endocardium and moderator band as part of the ventricular cavity [ 44 ]. Furthermore, SI and FS are calculated by a mathematical formula (SI: end-diastolic longitudinal diameter/end-diastolic transverse diameter, for each segment; FS: (end-diastolic transverse diameter-end-systolic transverse diameter)/end-diastolic transverse diameter, for each of the 24 segments), which may increase the error of both measures and explain the poorer reproducibility compared to other parameters that do not apply formulas.…”

“…Endocardial border was tracked semi-automatically, obtaining a speckle-tracking algorithm, along the cardiac cycle ( Figure 2 ). End-diastolic endocardial tracking was then adjusted if necessary, especially the RV, so that the endocardium, the muscular trabeculations and the moderator band were considered the RV cavity [ 44 ]. Both ventricles were divided into 24 segments automatically [ 27 ] to allow analysis of the base (segments 1–8), mid ventricle (segments 9–16) and apex (segments 17–24).…”

Prescriptive standards of echocardiographic morphometric and functional parameters in uncomplicated monochorionic diamniotic fetuses

“…We also demonstrated high feasibility and reproducibility for these measurements by 2D and M‐mode. These charts represent novel longitudinal charts constructed following current standardized landmarks to measure different cardiac morphometric and functional parameters 28–41 . Our group has previously demonstrated that uncomplicated MCDA twin fetuses present echocardiographic differences as a result of cardiac adaptation to volume/pressure overload when compared to singletons, 18 therefore, the use of our curves could help distinguish more accurately between adaptative or abnormal cardiovascular changes associated to MC pregnancy complications, optimizing the available therapeutic interventions.…”

“…FAC was calculated as = [(end‐diastolic RV area−end‐systolic RV area)/end‐diastolic RV area] × 100 37 . Manual tracing of the RV area is explained in the cardiac dimensions section 37 …”

“…Finally, right systolic function included the study of the fractional area change (FAC), which is a surrogate of ejection fraction and correlates with the RV ejection fraction better than other parameters. FAC was calculated as = [(end‐diastolic RV area−end‐systolic RV area)/end‐diastolic RV area] × 100 37 . Manual tracing of the RV area is explained in the cardiac dimensions section 37 …”