Diagnostic value of the myocardial performance index and doppler parameters in detecting fetal growth restriction in pregnancies complicated by hypertensive disorders

Introduction

Hypertensive disorders in pregnancy (HDP), such as gestational hypertension and preeclampsia, are among the most common complications affecting maternal and fetal health, occurring in approximately 5–10% of pregnancies worldwide (1). These conditions are associated with significant maternal and perinatal morbidity and mortality, primarily due to their adverse effects on placental function, leading to impaired fetal growth (2-4). One of the most concerning outcomes of hypertensive disorders is fetal growth restriction (FGR), a condition where the fetus fails to achieve its expected growth potential in utero (5,6). FGR is closely linked to perinatal complications, including preterm birth, stillbirth, and long-term neurodevelopmental and cardiovascular consequences for the offspring (7,8).

Hypertensive disorders disrupt placental blood flow, reducing oxygen and nutrient delivery to the fetus, which can impair fetal development and compromise organ function, including the heart (9,10). Previous research has demonstrated that fetuses with FGR often exhibit cardiac remodeling and dysfunction, with altered ventricular geometry and impaired systolic and diastolic performance (11,12). These changes may increase the risk of perinatal morbidity and even influence cardiovascular health later in life (13,14). However, there is still much to learn about the early detection of fetal cardiac dysfunction in pregnancies complicated by hypertensive disorders.

In recent years, fetal echocardiography has become a critical tool for evaluating fetal cardiac function, allowing clinicians to assess systolic and diastolic performance non-invasively. The myocardial performance index (MPI), also known as the Tei index, is an echocardiographic parameter that provides a comprehensive assessment of both systolic and diastolic function by measuring the ratio of isovolumetric contraction and relaxation times to the ejection time (ET) (15,16). The MPI is widely used due to its simplicity, reproducibility, and ability to detect subtle changes in cardiac function, even in the absence of overt structural abnormalities (17,18). Studies suggest that the MPI may be a valuable marker for identifying fetal cardiac dysfunction in pregnancies affected by FGR (19,20).

Additionally, studies report that other fetal blood flow spectral indices, including the umbilical artery pulsatility index (UA-PI), middle cerebral artery pulsatility index (MCA-PI), and ductus venosus pulsatility index (DV-PI), are valuable for assessing placental blood flow and fetal oxygenation status. The UA-PI reflects changes in placental vascular resistance, typically increasing in cases of FGR. The MCA-PI assesses cerebral blood flow, with a decrease often indicating “brain-sparing” due to fetal hypoxia (21). The DV-PI provides insights into fetal right heart function and venous return, with abnormal DV-PI suggesting potential risks of chronic hypoxia or heart failure (22). Therefore, the combined use of MPI with these spectral Doppler indices allows clinicians to more comprehensively assess fetal cardiac function and placental hemodynamics, offering a basis for timely intervention.

In summary, this study aimed to evaluate the diagnostic value of the MPI, in combination with the early (E) to late (A) diastolic filling (E/A) ratios of the mitral and tricuspid valves, and Doppler parameters of the umbilical artery, middle cerebral artery, and ductus venosus, in detecting FGR in pregnancies complicated by hypertensive disorders. By exploring the relationship between maternal hypertension, fetal cardiac function, and growth outcomes, we aimed to enhance early detection and improve management strategies for at-risk pregnancies. We present this article in accordance with the STROBE reporting checklist (available at https://qims.amegroups.com/article/view/10.21037/qims-2025-2056/rc).

Methods

Study population

A total of 284 pregnant women were recruited from the Department of Ultrasound Imaging at the Postgraduate Union Training Base of Xiangyang No. 1 People’s Hospital between April 2023 and October 2024. After applying the exclusion criteria, 202 participants were included in the study. Of the 202 participants, 95 were assigned to the control group, 75 to the HDP without FGR group, and 32 to the HDP with FGR group. Data collection included fetal biological indicators, Doppler blood flow indices, and clinical data, along with a comprehensive evaluation of fetal cardiac function. Statistical analyses were performed accordingly (Figure 1).

Figure 1 Study recruitment flowchart. FGR, fetal growth restriction; HDP, hypertensive disorders of pregnancy.

HDP was diagnosed according to the International Society for the Study of Hypertension in Pregnancy (ISSHP) (23) criteria for pregnancies with elevated blood pressure, defined as a systolic blood pressure ≥140 mmHg and/or a diastolic blood pressure ≥90 mmHg. FGR was diagnosed using the following criteria: an estimated fetal weight (EFW) below the 3rd percentile, or an EFW below the 10th percentile with accompanying Doppler evidence of placental dysfunction. This Doppler evidence included an UA-PI exceeding the 95th percentile, the absence of umbilical artery end-diastolic flow (UAEDF), reverse UAEDF, or a cerebroplacental ratio (CPR) below the 5th percentile (Figure 2). The exclusion criteria included chronic systemic diseases, multiple gestations, chronic drug use, fetal congenital and chromosomal abnormalities, and coexisting pregnancy complications such as gestational diabetes mellitus, preeclampsia, chorioamnionitis, and premature rupture of membranes, and/or refusal to participate in the study.

Figure 2 Doppler assessment of umbilical artery blood flow. The figure shows Doppler measurements of the umbilical artery. The prefix Umb- denotes parameters pertaining to the umbilical artery. Key parameters include: Umb-PS, Umb-ED, Umb-S/D, Umb-PI, Umb-RI, Umb-MD, Umb-TAMax, Umb-HR, Umb-VTI. ED, end-diastolic velocity; HR, fetal heart rate; MD, minimum diastolic velocity; PI, pulsatility index; PS, peak systolic velocity; RI, resistance index; S/D, systolic/diastolic ratio; TAMax, time-averaged maximum velocity; VTI, velocity-time integral.

All demographic data were collected from medical records. Maternal characteristics, including maternal age (MA) at recruitment, gestational age (GA) at recruitment, and body mass index (BMI), were documented. Obstetric characteristics, such as EFW and GA at delivery, were recorded. The neonatal characteristics included the neonatal weight percentile and birth weight.

GA was calculated from the last menstrual period and verified with first-trimester ultrasound measurements. Ultrasound evaluations were conducted using VOLUSON E10 ultrasound machines with the RM6C or C5-1 transducer (GE Healthcare, Chicago, IL, USA) by a single investigator with 10 years of obstetric experience. Following fetal anatomical assessment, fetal biometric parameters, EFW, and Doppler parameters were measured, including the DV-PI, UA-PI, MCA-PI, and MPI, with additional parameters recorded for the isovolumic relaxation time (IRT), isovolumic contraction time (ICT), ET, mitral valve early (E) to late (A) diastolic filling velocity ratio (MV-E/A ratio), tricuspid valve early (E) to late (A) diastolic filling velocity ratio (TV-E/A ratio), and CPR, calculated by dividing the MCA-PI by the UA-PI.

The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethics Committee of Xiangyang No. 1 People’s Hospital, School of Medicine, Wuhan University of Science and Technology (No. 2021KYLX02). All participants provided written informed consent for fetal ultrasonography and were briefed on both the reliability and limitations of the procedure.

Measurement of fetal cardiac function

Initially, the apical four-chamber view of the fetal heart was obtained in a transverse section of the fetal thorax. From this view, the five-chamber perspective was achieved by cranially angulating the transducer. Once the aortic valve (AV) and mitral valve (MV) were clearly visible, a pulse Doppler sample gate was set to approximately 3–4 mm, ensuring it captured both the lateral wall of the ascending aorta and the internal leaflet of the MV. The angle of insonation was kept as low as possible, ideally aligned close to 0 degrees to the direction of blood flow, to minimize potential overestimation of the time intervals used for the MPI calculation. A high wall motion filter was calibrated to 300 Hz, and the Doppler gain was adjusted to minimize artifacts while clearly detecting valve clicks. Doppler waveforms representing the opening and closing of the MV and AV were recorded, with the Doppler sweep velocity set at 5 cm/s. The E wave (early ventricular filling) and A wave (active atrial filling) were identified, along with the flow pattern of the AV. The time cursor was placed at the onset of the clicks.

Three key intervals in the cardiac cycle were defined: the ICT, IRT, and ET. The ICT was measured from the beginning of MV closure to the end of AV opening, while the IRT was measured from MV opening to AV closure. The ET was defined as the time from AV opening to closure. The MPI was then calculated using the following formula: MPI = (ICT + IRT)/ET. To ensure reproducibility, each measurement was repeated three times, and the average value was used for analysis (Figure 3).

Figure 3 Measurement of MPI by Doppler ultrasound. The image shows the Doppler echocardiographic assessment of left ventricular function using the MPI. The MPI was calculated using time intervals derived from Doppler waveforms. LVOT-ICT: isovolumetric contraction time; LVOT-IRT: isovolumetric relaxation time; LVOT-Eject Time: left ventricular ejection time; LVOT-TEI (ICT, IRT): The Tei Index or MPI, calculated as the sum of ICT and IRT divided by the ejection time, yielding a value of 0.60. LVOT, left ventricular outflow tract; MPI, myocardial performance index.

Statistical analysis

The statistical analyses were conducted using SPSS version 26.0. Continuous variables were presented as the mean ± standard deviation (SD). The Kolmogorov-Smirnov test was used to evaluate the relevance of the data to normal distribution. The Mann-Whitney U-test was used to compare the statistical significance between two independent groups according to the distribution ranges. Spearman correlation tests were performed to assess the association of quantitative variables based on the distribution ratios. Receiver operating characteristic (ROC) curve analysis was used to determine the predictive accuracy for FGR and HDP. A P value less than 0.05 was considered statistically significant.

Results

Participant selection and final study cohort

In this study, 284 pregnant women initially volunteered to participate. Based on the exclusion criteria, 17 were excluded for chronic systemic diseases, 13 for multiple gestations, 15 for chronic drug use, 12 for fetal congenital or chromosomal abnormalities, 17 for coexisting pregnancy complications other than HDP, and eight for refusal to participate. Ultimately, 202 women were included in the final analysis; 95 were assigned to the control group, 75 to the HDP without FGR group, and 32 to the HDP with FGR group (Figure 1).

Comparison of maternal characteristics and neonatal outcomes

There were no statistically significant differences in BMI among the control, HDP without FGR, and HDP with FGR groups (P>0.05). However, significant differences were observed in MA at recruitment, GA at recruitment, EFW, GA at delivery, neonatal weight percentile, and birth weight across the groups (P<0.05). Specifically, MA and GA at recruitment were significantly higher in the HDP without FGR group than in the control and HDP with FGR groups (P<0.05). Additionally, EFW and GA at delivery were significantly lower in the HDP with FGR group than in both the control and HDP without FGR groups (P<0.05). The neonatal weight percentile and birth weight were also significantly reduced in the HDP with FGR group compared to both other groups (P<0.05) (Table 1).

Comparison of fetal cardiac function

Comparison of fetal cardiac function findings among the three groups (control, HDP without FGR, and HDP with FGR) demonstrated statistically significant differences in several parameters (P<0.05). Specifically, the MPI, MV-E/A ratio, TV-E/A ratio, UA-PI, MCA-PI, DV-PI, and CPR values varied significantly across the groups. In particular, the MPI, MV-E/A ratio, TV-E/A ratio, UA-PI, and DV-PI values were higher in the HDP groups compared to the control group (P<0.05), while the CPR values were lower. Further, the HDP with FGR group showed significantly lower CPR values but higher MPI, UA-PI, and DV-PI values compared to the HDP without FGR group (P<0.05) (Table 2).

Correlation analysis of birth weight with gestational outcomes and fetal parameters

Spearman’s correlation tests revealed statistically significant positive correlations between birth weight and GA (r=0.634, P=0.012), as well as between birth weight and EFW (r=0.773, P=0.002). A significant negative correlation was observed between birth weight and MPI (r=–0.405, P=0.036), as well as birth weight and the UA-PI (r=–0.317, P=0.039). No statistically significant correlations were found between birth weight and other Doppler, clinical, and fetal cardiac parameters (Table 3).

ROC curve analysis

The ROC curve analysis comparing normal pregnancies and those with HDP revealed that the UA-PI had the highest discriminative power with an ROC of 0.91 [95% confidence interval (CI): 87.0–92.1]. The ROC values for other indicators were as follows: ICT, 0.74 (95% CI: 55.2–84.4); EFW, 0.84 (95% CI: 69.5–94.8); CPR, 0.72 (95% CI: 54.3–90.6); MPI, 0.78 (95% CI: 66.5–89.7); and MV-E/A, 0.75 (95% CI: 57.0–92.3) (Figure 4).

Figure 4 ROC curve to predict HDP. CPR, cerebroplacental ratio; EFW, estimated fetal weight; HDP, hypertensive disorders of pregnancy; ICT, isovolumic contraction period; MPI, myocardial performance index; MV-E/A ratio, mitral valve early (E) to late (A) diastolic filling velocity ratio; ROC, receiver operating characteristic; UA-PI, umbilical artery pulsatility index.

The ROC curve analysis comparing pregnancies with HDP and normal fetal growth, as well as pregnancies with HDP and FGR showed an area under the curve [AUC] of 0.86 (95% CI: 77.0–97.9%) for EFW, 0.72 (95% CI: 50.4–93.4%) for the CPR, 0.86 (95% CI: 73.8–97.1%) for the UA-PI, and 0.78 (95% CI: 62.0–94.4%) for the MPI (Figure 5).

Figure 5 ROC curve to predict HDP with FGR. CPR, cerebroplacental ratio; EFW, estimated fetal weight; FGR, fetal growth restriction; HDP, hypertensive disorders of pregnancy; MPI, myocardial performance index; ROC, receiver operating characteristic; UA-PI, umbilical artery pulsatility index.

Discussion

The study results highlight the critical relationship between HDP and FGR, emphasizing the importance of early detection and monitoring of fetal cardiac function. The significant increase in MPI observed in the HDP with FGR group compared to the control group suggests that hypertensive disorders may lead to increased cardiac workload in fetuses, which is consistent with previous literature indicating that FGR fetuses often exhibit cardiac dysfunction and remodeling (24). This finding aligns with studies that have shown that fetal cardiac performance is adversely affected by placental insufficiency, a common consequence of hypertensive disorders (25,26). The negative correlation between the MPI and EFW further underscores the notion that as cardiac workload increases, fetal growth is compromised, potentially leading to adverse outcomes such as preterm birth and long-term cardiovascular issues in offspring.

Moreover, the study findings regarding the Doppler parameters, particularly the UA-PI, reinforce the utility of these measurements in clinical practice. The lower UA-PI in the HDP with FGR group compared to the control group indicates impaired placental perfusion, which is a hallmark of FGR. This is consistent with existing literature that demonstrates that Doppler ultrasound can effectively assess placental blood flow and predict adverse perinatal outcomes (27). The high AUC for the UA-PI in the ROC analysis further supports its role as a reliable diagnostic tool in identifying FGR in pregnancies complicated by hypertensive disorders. Such findings advocate for the integration of Doppler assessments into routine prenatal care for high-risk populations, enabling timely interventions that could improve fetal outcomes.

The study results also contribute to the growing body of evidence suggesting that the MPI can serve as a valuable marker for fetal cardiac dysfunction in the context of hypertensive disorders. The simplicity and reproducibility of MPI measurements make it an attractive option for clinicians seeking to monitor fetal well-being non-invasively. Previous studies have shown the efficacy of the MPI as an indicator of both systolic and diastolic function, reinforcing its potential as a prognostic tool in pregnancies complicated by FGR. The current findings suggest that the MPI, in conjunction with traditional Doppler parameters, could enhance the diagnostic accuracy for identifying fetuses at risk for growth restriction, thereby facilitating better management strategies (28,29).

Further, the correlation analysis, which revealed a significant positive relationship between EFW and both the MPI and Doppler parameters, emphasized the interconnectedness of fetal growth and cardiac function. This relationship suggests that monitoring these parameters could provide insights into the overall health of the fetus, enabling the proactive management of pregnancies at risk for complications. The implications of these findings extend beyond immediate clinical applications; they also highlight the need for further research into the mechanisms underlying fetal cardiac dysfunction in the context of hypertensive disorders. Understanding these mechanisms could pave the way for developing targeted interventions aimed at improving fetal outcomes in affected pregnancies (30-32).

In addition to the clinical implications, the study raises important considerations regarding the potential long-term consequences of FGR on cardiovascular health. Research has indicated that individuals who experienced FGR are at an increased risk for developing cardiovascular diseases later in life (33,34). This underscores the importance of not only identifying FGR during pregnancy but also implementing follow-up strategies to monitor the long-term health of these individuals. The findings of this study could inform future research aimed at elucidating the long-term effects of FGR on cardiovascular health and the potential benefits of early interventions.

The limitations of this study must be acknowledged. First, the sample size, while adequate for preliminary observations, imposes constraints. The cohort was unevenly distributed, with a notably larger control group compared to the high-risk HDP with FGR group. This significant disparity, though reflective of the lower prevalence of the severe comorbid condition in the clinical population, reduces the statistical power for inter-group comparisons and increases the risk of Type II errors, potentially masking subtle but real differences. It may also limit the robustness of multivariate adjustments and the feasibility of meaningful subgroup analyses within the HDP + FGR cohort. Second, regarding the methodological scope, our functional assessment was confined to conventional Doppler velocimetry and MPI derived from pulsed-wave Doppler. We did not employ more innovative and potentially sensitive modalities, such as speckle tracking echocardiography (STE). Recent evidence suggests that STE-derived strain and strain rate analysis can detect subclinical myocardial dysfunction, and provide incremental diagnostic and prognostic information over conventional parameters both in fetuses and in pregnancies complicated by hypertensive disorders (35,36). Consequently, while our findings highlight the utility of accessible conventional tools, they may not capture the full spectrum of early cardiac dysfunction. These limitations underscore the need to interpret our results as preliminary and hypothesis-generating. They strongly advocate for the future validation of these parameters in larger, prospective, and ideally balanced multicenter cohorts. Further, they point clearly to a promising research direction: integrating advanced quantitative techniques like STE with conventional biomarkers to develop more sensitive and comprehensive predictive models for FGR in high-risk pregnancies.

Conclusions

The study findings underscore the critical role of the MPI and Doppler parameters in the early detection of FGR in pregnancies complicated by hypertensive disorders. The significant alterations in fetal cardiac function associated with these conditions highlight the need for vigilant monitoring and proactive management strategies. By integrating these diagnostic tools into clinical practice, healthcare providers can improve outcomes for both mothers and their infants, ultimately contributing to a reduction in perinatal morbidity and mortality associated with HDP.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://qims.amegroups.com/article/view/10.21037/qims-2025-2056/rc

Data Sharing Statement: Available at https://qims.amegroups.com/article/view/10.21037/qims-2025-2056/dss

Funding: The study was supported by Hubei Provincial Natural Science Foundation (No. 2025AFB845) and Graduate Innovation and Entrepreneurship Fund of Wuhan University of Science and Technology (No. JCX2024044).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-2025-2056/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethics Committee of Xiangyang No. 1 People’s Hospital, School of Medicine, Wuhan University of Science and Technology (No. 2021KYLX02). All participants provided written informed consent for fetal ultrasonography and were briefed on both the reliability and limitations of the procedure.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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(English Language Editor: L. Huleatt)