Reference ranges for fetal tricuspid and mitral annular plane systolic excursions

Introduction

Echocardiography is the standard modality essential for evaluating fetal cardiac function. Evaluation of fetal cardiac function is particularly critical in cases of congenital fetal cardiac anomalies, fetal tumors [1], fetal anemia [2], fetal growth restriction (FGR) [3], twin-to-twin transfusion syndrome (TTTS) [4], 5], and placental tumors [1]. Various sonographic techniques are used to assess systolic, diastolic, and global cardiac functions. For instance, the E/A ratio is used to evaluate diastolic function, while parameters such as shortening fraction, ejection fraction, tricuspid annular plane systolic excursion (TAPSE), and mitral annular plane systolic excursion (MAPSE) are utilized for systolic function. The myocardial performance index provides an assessment of global cardiac function. However, no main method for functional assessment. This study will focus on measuring fetal systolic function [6], 7].

Fetal systolic function can be quantified using parameters including shortening fraction, ejection fraction, TAPSE, and MAPSE [6]. Although shortening and ejection fractions provide valuable data, they typically show changes in the late stages of fetal cardiac dysfunction. Moreover, the complexity of their calculation may be limited in specific situations. Conversely, TAPSE and MAPSE reflect the maximum vertical displacement of the lateral leaflet of the atrioventricular valve using M-mode, and their values can detect changes as early as the initial stages of cardiac dysfunction. These methods are simple and easy to perform and do not require advanced ultrasonography techniques. Moreover, TAPSE and MAPSE be measured using standard ultrasound equipment and are practical for routine clinical applications.

While the normal reference ranges for TAPSE and MAPSE have been extensively studied in adult [8], [9], [10] and pediatric [11], [12], [13], [14] populations, data regarding fetal reference ranges remain limited, particularly among Southeast Asian populations. As such, this study aimed to establish normal reference ranges for TAPSE and MAPSE in fetuses at 18 + 0 to 37 + 6 weeks’ gestation.

Materials and methods

Sonography

Examinations were performed using an ultrasound device (Voluson E10 or S8, GE Healthcare Ultrasound, Milwaukee, WI, USA) equipped with an XDclear wide-band convex probe C1-6-D, with a maximum bandwidth of 2–5 MHz. GA was determined based on the last menstrual period and was confirmed using ultrasonography in the first-trimester. All participants underwent fetal anomaly scans by J.K. according to the International Society of Ultrasound in Obstetrics and Gynecology Practice Guidelines for routine mid-trimester fetal ultrasound [16]. Fetal biometry was performed, and estimated fetal weight (EFW) was calculated using the equation described by Hadlock et al. [17].

Positional measurements of TAPSE (Figure 1A) and MAPSE (Figure 1B) were obtained using a four-chamber view with the fetal heart positioned at 12 or 6 o’clock. The image was adjusted and conventional M-mode was used. A cursor was placed through the lateral leaflets of the tricuspid and mitral valves, maintaining an insonation angle of <15° relative to the interventricular septum during maternal breath-holding and fetal rest. The maximum longitudinal displacement of atrioventricular valve motion was measured. Each evaluation was performed 3 times and the mean value was calculated and used in the analysis [18].

Figure 1:

Ultrasound images of the apical four-chamber view of the fetal cardiac demonstrated longitudinal atrioventricular valve motion measurement with the M-mode. (A) Tricuspid annular plane systolic excursion (TAPSE), (B) mitral valve annular plane systolic excursion (MAPSE). Longitudinal displacement measurement is demonstrated at the bottom of the image.

Results

Data from 280 pregnant women who fulfilled the inclusion and exclusion criteria for establishing a normal reference range were included. The demographic characteristics of the study population and perinatal outcomes are summarized in Table 1. The mean maternal age was 33.0 years, and the mean pre-pregnancy body mass index was 23.8 kg/m². Most participants were pregnant Thai women. The median GA at delivery was 38 weeks, with a mean birth weight of 3,081 g. A total of 135 and 145 pregnant women underwent vaginal and cesarean deliveries, respectively, with mean Apgar scores of 8 and 9 at 1 and 5 min. Normal reference ranges for TAPSE based on GA and EFW, respectively, are summarized in Tables 2 and 3. The mean TAPSE across GA ranged from 3.76 to 9.08 mm, while the mean TAPSE across EFW ranged from 3.42 to 9.30 mm. Scatterplots for TAPSE vs. GA and EFW, illustrating an increasing trend with gestational age, are presented in Figures 2 and 3. Normal reference ranges for the MAPSE based on GA and EFW are presented in Tables 4 and 5. The mean MAPSE across GA ranged from 3.10 to 6.34 mm, while the mean MAPSE across EFW varied from 2.71 to 6.60 mm. Scatterplots for MAPSE vs. GA and EFW, demonstrating an increase with GA, are presented in Figures 4 and 5. Both TAPSE and MAPSE exhibited significant positive correlations with GA and EFW. The optimal model for predicting these values was a logarithmic transformation that provided the best fit. Notably, the mean TAPSE values consistently exceeded the MAPSE values at all GAs.

Figure 2:

Scatterplots of tricuspid annular plane systolic excursion (TAPSE) based on gestational age (GA) in the study population. Estimated 1st, 2.5th, 5th, 10th, 25th, 50th, 50th, 75th, 90th, 95th, 97.5th, and 99th percentiles curves are shown.

Figure 3:

Scatterplots of tricuspid annular plane systolic excursion (TAPSE) based on estimated fetal weight (EFW) in the study population. Estimated 1st, 2.5th, 5th, 10th, 25th, 50th, 50th, 75th, 90th, 95th, 97.5th, and 99th percentiles curves are shown.

Figure 4:

Scatterplots of mitral annular plane systolic excursion (MAPSE) based on gestational age (GA) in the study population. Estimated 1st, 2.5th, 5th, 10th, 25th, 50th, 50th, 75th, 90th, 95th, 97.5th, and 99th percentiles curves are shown.

Figure 5:

Scatterplots of mitral annular plane systolic excursion (MAPSE) based on estimated fetal weight (EFW) in the study population. Estimated 1st, 2.5th, 5th, 10th, 25th, 50th, 50th, 75th, 90th, 95th, 97.5th, and 99th percentiles curves are shown.

The ICC between the two sonographers (i.e., J.K. and R.K.) for TAPSE was 0.94 (95 % CI 0.77–0.99) and 0.91 (95 % CI 0.65–0.98) for MAPSE. The ICC for two repeat measurements by J.K. was 0.91 (95 % CI, 0.74–0.97) for TAPSE and 0.88 (95 % CI, 0.65–0.96) for MAPSE. The Bland-Altman plots demonstrate the mean difference of repeated measurement by the same examiner (intra-observer) for TAPSE and MAPSE, which are 0.12 ± 0.65 mm and −0.12 ± 0.53 mm, respectively Figures 6 and 7. The mean difference between two examiners (inter-observer) for TAPSE and MAPSE were −0.03 ± 0.60 mm and 0.28 ± 0.70 mm, respectively, Figures 8 and 9.

Figure 6:

Bland–Altman plot demonstrating intra-observer agreement of tricuspid annular plane systolic excursion (TAPSE) measurements.

Figure 7:

Bland–Altman plot demonstrating intra-observer agreement of mitral annular plane systolic excursion (MAPSE) measurements.

Figure 8:

Bland–Altman plot demonstrating inter-observer agreement of tricuspid annular plane systolic excursion (TAPSE) measurements.

Figure 9:

Bland–Altman plot demonstrating inter-observer agreement of mitral annular plane systolic excursion (MAPSE) measurements.

Discussion

Several studies have established normal reference values for fetal TAPSE and MAPSE in various populations, including Israel, China, Australia, and Brazil [18], [19], [20], [21]. The reference values at corresponding gestational ages vary across these studies, suggesting that population-specific differences may influence these parameters. Currently, no studies have investigated these parameters in Southeast Asian populations. This study established normal reference ranges for TAPSE and MAPSE in fetuses between 18 + 0 and 37 + 6 weeks’ GA. TAPSE and MAPSE progressively increased with advancing GA and EFW, exhibiting a logarithmic correlation. Our results are similar to those reported by Herling et al. [22].

However, previous studies reported a linear correlation, which differed slightly from our findings. These differences may be attributed to our study’s earlier GA range [19], [20], [21] and larger sample size compared with previous studies [18], 20]. Several studies evaluating TAPSE in healthy pediatric populations have demonstrated a positive correlation between TAPSE values and increasing weight and body surface area [11], [12], [13], consistent with our findings of a positive correlation between TAPSE and MAPSE with EFW.

TAPSE consistently exceeded MAPSE throughout gestation, reflecting a higher fetal cardiac output from the right ventricle than that from the left ventricle. This suggests that fetal right ventricular compliance was greater than left ventricular compliance [23]. These findings are consistent with those from previous studies [18], [19], [20], [21], [22]. Using TAPSE and MAPSE based solely on GA may not be appropriate, particularly in conditions such as FGR, in which fetal weight does not correspond to GA. EFW-based assessment provides a more accurate evaluation of fetal cardiac function. Our study provides percentile tables for TAPSE and MAPSE correlated with EFW, which may be clinically useful for fetuses diagnosed with these specific conditions.

TAPSE and MAPSE are widely used in various clinical contexts to evaluate fetal cardiac function. Several studies have assessed TAPSE and MAPSE under specific pathological conditions, including fetal anemia. Pre-intrauterine blood transfusion (IUT) measurements revealed annular plane systolic excursion values above the normal reference range, significantly decreasing post-IUT [2]. Similarly, a study involving 11 cases of placental tumors found that 8 of 11 fetuses exhibited TAPSE values above the normal reference range [1]. These findings suggest that the annular plane systolic excursion values in high cardiac output states tend to exceed the normal reference range.

Conversely, studies focusing on fetal heart failure have demonstrated significantly lower TAPSE, MAPSE, and myocardial performance index values than those of normal fetuses, often falling >2 standard deviations below the mean [24]. Furthermore, in fetuses with FGR, TAPSE values are significantly lower than those in normal fetuses [3]. Additional research investigating maternal preeclampsia has revealed a decrease in fetal TAPSE [25]. In TTTS, donor and recipient twins exhibit TAPSE values that are lower than those of the normal reference range [4], 5]. These findings underscore the clinical utility of TAPSE and MAPSE for assessing fetal systolic function under various conditions. Consequently, establishing robust reference ranges is crucial for the accurate diagnosis and effective monitoring of fetal systolic cardiac function.

To the best of our knowledge, our study represents the largest dataset of normal reference ranges in a Southeast Asian population. Data collection began at 18 weeks’ GA, earlier than in previous studies [19], [20], [21]. Establishing a reference for early GAs has significant advantages in the early detection of fetal cardiac dysfunction, which may benefit the early management of conditions, such as TTTS [4], 5] and early FGR [3], 26].

Currently, various methods are available to assess fetal cardiac function, including M-mode for TAPSE, MAPSE, and shortening fraction; and B-mode and pulse-wave Doppler (PWD) for stroke volume, cardiac output, and myocardial performance index. Despite these options, no standardized method for fetal cardiac assessment has been established [6]. Our study specifically focused on the annular plane systolic excursion using the M-mode due to its simplicity, ease of measurement and interpretation, and availability on all ultrasound devices. Additionally, it does not require advanced ultrasonography skills, making it a practical and sensitive tool for detecting cardiac dysfunction. Our study provided an ICC for inter-observer variability, indicating that the measurement method was reproducible.

A key consideration when using conventional M-mode is that the M-mode cursor must be parallel to the interventricular septum. Deviations from this alignment increase measurement errors. Previous studies comparing conventional M-mode to angular M-mode have shown that TAPSE and MAPSE values remain nearly identical when the cursor-interventricular septum angle is maintained <30° [19]. Our study optimized accuracy by maintaining an insonation angle <15°, which provides a reliable reference range.

Conclusions

In summary, the present investigation established normal reference ranges for TAPSE and MAPSE to assess fetal systolic cardiac function. TAPSE and MAPSE increased with advancing GA and fetal weight. These parameters are simple, easy to use, and convenient for evaluating ventricular systolic function. They can be used to assess fetal cardiac function in conditions such as FGR, congenital cardiac anomalies, fetal and placental tumors, fetal anemia, and TTTS.