Left atrial shortening fraction in fetuses with and without myocardial hypertrophy in diabetic pregnancies

Impact of maternal diabetes mellitus on fetal atrial strain

While Maternal Diabetes Mellitus (DM) is well known to affect the size and function of multiple fetal organ systems, effects on developing heart chamber function remain difficult to assess. We sought to determine the independent impact of maternal DM on fetal cardiac function in middle pregnancy. We prospectively recruited mothers with all categories of DM and non-diabetic healthy controls (NDC). Echocardiograms were optimized for chamber quantification and strain analysis. Left atrial area (LAA), LA strain (LAS), right atrial strain (RAS), global longitudinal ventricular strain (GLS) and Right ventricular free wall strain (RV FWS) were evaluated by 2 blinded operators. After excluding 9 mothers with poor fetal image quality, images from 104 mothers with DM and 47 NDC were analyzed. Mothers with DM and NDCs were well matched for age, blood pressure, smoking prevalence, and gestational age. Fetal heart rate (FHR) was significantly higher in fetuses of mothers with DM compared to NDC (147 ± 10 bpm vs. 144 ± 8, p = 0.04). LAA in fetuses of mothers with DM trended towards being larger in size (1.68 ± 0.4cm2 vs. 1.56 ± 0.4cm2, p = 0.08). Fetal septal diameters were larger in maternal DM compared to NDC (2.7 ± 0.5 cm vs. 2.5 ± 0.5 cm, p = 0.001). GLS was similar between the groups. Fetal LAS was lower in maternal DM (28.8 ± 8.8% vs. 33.3 ± 10.4%, p = 0.007) and was independently associated with maternal DM after adjusting for GLS and FHR. Fetal RAS was lower in maternal DM (27.7 ± 10.4% vs. 31.8 ± 10.3%, p = 0.007), however only determinates were estimated fetal weight and RV FWS. Maternal DM independently impairs fetal LA function in mid pregnancy. These early functional changes in the developing heart warrant future studies investigating impact on cardiovascular health.

Left atrial shortening fraction to predict fetal cardiac abnormalities and dysfunction in gestational diabetes mellitus

Objective

To evaluate the diagnostic efficiency of left atrial shortening fraction (LASF) in the detection of fetal cardiac abnormalities and dysfunction in patients with gestational diabetes mellitus (GDM).

Methods

In this study, we enrolled 256 pregnant women and divided them into GDM group (n = 156) and control group (n = 100). Fetal echocardiography was performed at 24-28 weeks of gestation to measure the LASF and interventricular septum (IVS) thickness. Based on IVS thickness, the GDM group was subdivided into the septal hypertrophy group (GDM I, n = 62) and non-septal hypertrophy group (GDM II, n = 94). LASF and IVS thickness were compared between the GDM and control groups and between GDM I and GDM II groups. Receiver operating characteristic (ROC) analysis was performed to determine the diagnostic accuracy of LASF in predicting septal hypertrophy.

Results

The GDM group had a larger IVS thickness (P < 0.05) but a lower LASF level (P < 0.001) than those of the control group. GDM I group had significantly lower LASF level than that in the GDM II group (P < 0.001). At 38.41% as the cutoff value, the LASF can predict septal hypertrophy with diagnostic sensitivity and specificity of 96.7% and 65.2%, respectively.

Conclusion

Fetal GDM are more likely to induce septal hypertrophy and ventricular dysfunction. LASF is a good indicator of septal hypertrophy or early diastolic dysfunction without septal hypertrophy.

Evaluation of cardiac function in fetuses of mothers with gestational diabetes

OBJECTIVE

The purpose of this study was to assess fetal cardiac function in normal fetuses (control group) compared to those who are exposed to gestational diabetes mellitus using different echocardiographic measurements, and to explore the application of left atrial shortening fraction in determination of fetal diastolic function with gestational diabetes mellitus.

METHODS

A total of 50 women with gestational diabetes and 50 women with a healthy pregnancy were included in the study. Fetal echocardiography was performed and structural as well as functional fetal cardiac parameters were measured. Data were compared between with or without fetal myocardial hypertrophy and the control group.

RESULTS

In the study group, out of 50 fetuses of gestational diabetic mothers, 18 had myocardial hypertrophy and 32 had normal septal thickness. Gestational age at time of examination did not differ significantly between the control and gestational diabetes group (p = 0.55). Mitral E/A ratio was lower in gestational diabetes group as compared to the control (p < 0.001). Isovolumetric relaxation and contraction times and myocardial performance index were greater in fetuses of gestational diabetic mothers (p < 0.001). In fetuses of gestational diabetic mothers with myocardial hypertrophy, left atrial shortening fraction was lower as compared to those without myocardial hypertrophy and those of the control group (p < 0.001).

CONCLUSIONS

The results of this study suggest that fetuses of gestational diabetic mothers have altered cardiac function even in the absence of septal hypertrophy, and that left atrial shortening fraction can be used as a reliable alternate parameter in the assessment of fetal diastolic function.

Gestational diabetes influences the expression of hypertrophic genes in left ventricle of rat's offspring

Objective(s):

Gestational diabetes increases the risk of congenital heart disease in the offspring, but the molecular mechanism underlying this process remains unclear. Therefore, the current study was conducted to assess the effects of induced gestational diabetes on expression of some involved genes in cardiac hypertrophy in the offspring of diabetic rats.

Materials and Methods:

Diabetes was induced in 40 adult Wistar rats by intraperitoneal injection of 45 mg/kg of streptozotocin. The day of appearance of the vaginal plug was assumed as day zero of gestation for inducing diabetes. After pregnancy, the offspring was maintained until they reach the age of 12 weeks. Then, their hearts were excised and were sectioned for molecular study. We analyzed the expression pattern of some hypertrophic genes by the quantitative real-time RT-PCR.

Results:

The mRNA expression levels of all studied genes including c-jun, c-fos, c-myc, alpha-myosin heavy chain (α-MHC), atrial natriuretic factor (ANF) and β-MHC, which are important in cardiomyocyte hypertrophy, were higher in the offspring of the diabetic group compared to controls. Significant differences were found for β-MHC and c-myc with P<0.01 and for α-MHC and c-fos with P<0.05.

Conclusion:

Gestational diabetes upregulates expression of c-jun, c-fos c-myc, α-MHC, ANF and β-MHC genes that are involved in cardiac hypertrophy in the offspring of diabetic rats.

Behaviour of the Foramen Ovale Flow in Fetuses with Intrauterine Growth Restriction

Background

Foramen ovale (FO) flow may be altered in IUGR. This study was designed to test this hypothesis.

Methods

Forty pregnant women (24–38 weeks) were divided into 3 groups: group I (IUGR), group II (adequate growth and maternal hypertension), and group III (normal controls). Impedance across the FO was assessed by the FO pulsatility index (FOPI): (systolic velocity − presystolic velocity)/mean velocity. Statistical analysis utilized ANOVA, Tukey test, and ROC curves.

Results

Mean FOPI in IUGR fetuses (n = 15) was 3.70 ± 0.99 (3.15–4.26); in the group II (n = 12), it was 2.84 ± 0.69 (2.40–3.28), and in the group III (n = 13), it was 2.77 ± 0.44 (2.50–3.04) (p=0.004). FOPI and UtA RI were correlated (r = 0.375, p=0.017), as well as FOPI and UA RI (r = 0.356, p=0.024) and, inversely, FOPI and MCA RI (r = −0.359, p=0.023).

Conclusions

The FO flow pulsatility index is increased in fetuses with IUGR, probably as a result of impaired left ventricular diastolic function.

Reference Ranges of Fetal Cardiac Biometric Parameters Using Three-Dimensional Ultrasound with Spatiotemporal Image Correlation M Mode and Their Applicability in Congenital Heart Diseases

To determine reference values for fetal heart biometric parameters using the spatiotemporal image correlation (STIC) M mode and their applicability in congenital heart diseases (CHDs). A cross-sectional prospective study was conducted with 300 singleton pregnancies between 20 and 33 + 6 weeks of gestation. Right ventricular wall thickness (RVWT), interventricular septum thickness (IVST), and left ventricular wall thickness (LVWT) were measured off-line using the STIC-M mode with the cursor perpendicular to the interventricular septum. Polynomial regressions adjusted with the coefficient of determination (R ²) were performed. The curves were applied to 14 fetuses with structural CHD. For the reproducibility calculations, the concordance correlation coefficient (CCC) was used. The mean RVWT, IVST, and LVWT were 0.34 ± 0.09 cm, 0.28 ± 0.09 cm, and 0.30 ± 0.07 cm, respectively. There was correlation between RVWT, IVST, and LVWT and gestational age (GA): RVWT = -0.002 + 0.013 × GA (R ² = 0.33), IVST = -0.011 + 0.011 × GA (R ² = 0.25), and LVWT = 0.056 + 0.009 × GA (R ² = 0.26). RVWT, IVST, and LVWT were altered (<5th or >95th percentile) in 5/14, 5/14, and 7/14 of the fetuses with CHD, respectively. For RVWT, IVST, and LVWT, intra-observer (CCC = 0.86, 0.85, and 0.87, respectively) and inter-observer (CCC = 0.86, 0.86, and 0.86, respectively) reproducibility were good/moderate. The reference ranges determined for fetal heart biometric parameters using STIC-M had good intra- and inter-observer reproducibility and were applicable to fetuses with CHD.

Maternal hyperglycemia leads to fetal cardiac hyperplasia and dysfunction in a rat model

Accelerated fetal myocardial growth with altered cardiac function is a well-documented complication of human diabetic pregnancy, but its pathophysiology is still largely unknown. Our aim was to explore the mechanisms of fetal cardiac remodeling and cardiovascular hemodynamics in a rat model of maternal pregestational streptozotocin-induced hyperglycemia. The hyperglycemic group comprised 107 fetuses (10 dams) and the control group 219 fetuses (20 dams). Fetal cardiac function was assessed serially by Doppler ultrasonography. Fetal cardiac to thoracic area ratio, newborn heart weight, myocardial cell proliferative and apoptotic activities, and cardiac gene expression patterns were determined. Maternal hyperglycemia was associated with increased cardiac size, proliferative, apoptotic and mitotic activities, upregulation of genes encoding A- and B-type natriuretic peptides, myosin heavy chain types 2 and 3, uncoupling proteins 2 and 3, and the angiogenetic tumor necrosis factor receptor superfamily member 12A. The genes encoding Kv channel-interacting protein 2, a regulator of electrical cardiac phenotype, and the insulin-regulated glucose transporter 4 were downregulated. The heart rate was lower in fetuses of hyperglycemic dams. At 13-14 gestational days, 98% of fetuses of hyperglycemic dams had holosystolic atrioventricular valve regurgitation and decreased outflow mean velocity, indicating diminished cardiac output. Maternal hyperglycemia may lead to accelerated fetal myocardial growth by cardiomyocyte hyperplasia. In fetuses of hyperglycemic dams, expression of key genes that control and regulate cardiomyocyte electrophysiological properties, contractility, and metabolism are altered and may lead to major functional and clinical implications on the fetal heart.

Myocardial hypertrophy and dysfunction in maternal diabetes

Diabetes in pregnancy, both pre-gestational and gestational, is a frequent cause of fetal myocardial hypertrophy, partly due to fetal hyperinsulinism. In fetal life, cardiac function may be impaired, especially during diastole, as a result of decreased left ventricular distensibility and altered left atrial dynamics secondary to myocardial hypertrophy. In neonates, the hypertrophy is a transient disorder, with spontaneous regression of the increased myocardial thickness during the first months of life. Nevertheless, cardiac hypertrophy may be associated with neonatal cardiomegaly and respiratory distress secondary to poor left ventricular compliance. The development of a number of new echocardiographic parameters discussed in this article, and primarily based on the pathophysiological consequences of myocardial hypertrophy, highlight an area of research priority: the assessment of diastolic function in fetuses of diabetic mothers with (and without) myocardial hypertrophy. A score for grading the severity of fetal diastolic dysfunction in these fetuses is proposed.

Influence of fetal respiratory movements on left atrial functional status

OBJECTIVE

Because fetal respiratory movements increase left ventricular compliance, we hypothesized that the left atrial shortening fraction increases during fetal respiratory motions.

METHODS

A group of 26 normal fetuses with gestational ages between 28 and 38 weeks were assessed in a prospective cross-sectional study. Left atrial telesystolic and presystolic diameters were measured during apnea and after five consecutive respiratory movements. Left atrial shortening fraction was obtained by the ratio: [maximal left atrium diameter (telesystolic) - minimal left atrium diameter (presystolic)]/maximal left atrium diameter (telesystolic). The mean of three measurements were considered. Two-tailed Student's t-test was used.

RESULTS

Mean gestational age was (mean ± SD) 30.7 ± 2.8 weeks. Mean left atrial telesystolic diameter in apnea was 10.6 ± 0.7 mm and during respiratory movements it was 10.5 ± 1.1 mm (p = 0.98). Presystolic left atrial diameter was 5.2 ± 0.1 mm in apnea and 4.4 ± 1.3 mm during respiratory movements (p < 0.001). Left atrial shortening fraction was 0.50 ± 0.05 in apnea and 0.58 ± 0.13 during respiratory movements (p < 0.001).

CONCLUSION

Left atrial shortening fraction is higher during respiratory movements as a result of increased left ventricular compliance and consequent optimization of left atrial functional status.

Behavior of pulmonary venous flow during fetal respiratory movements

OBJECTIVE

To test the hypothesis that fetal pulmonary venous flow pulsatility index is lower during fetal respiratory movements than in apnea.

DESIGN

Case control. SETTINGS/PATIENTS: Twenty-two normal fetuses of mothers without systemic disease were examined in apnea (controls) and in the presence of fetal respiratory movements (cases). Fetuses were examined by prenatal Doppler echocardiography with color flow mapping. The pulsatility index of the pulmonary vein was obtained by placing the pulsed Doppler sample volume over the right upper or left lower pulmonary vein, and calculating the ratio (maximum velocity [systolic or diastolic]-presystolic velocity/mean velocity).

RESULTS

Mean gestational age was 28.9 +/- 2.9 weeks. During fetal apnea, mean systolic, diastolic, and presystolic velocities were, respectively, 0.35 +/- 0.08 m/s, 0.26 +/- 0.07 m/s, and 0.09 +/- 0.03 m/s. In the presence of fetal respiratory movements, mean systolic, diastolic, and presystolic velocities were, respectively, 0.33 +/- 0.1 m/s, 0.28 +/- 0.08 m/s, and 0.11 +/- 0.04 m/s. Pulsatility index pulmonary vein in apnea was 1.25 +/- 0.23 (1.69 to 0.82), and during fetal respiratory movements it was 0.97 +/- 0.2 (1.53 to 0.61).

CONCLUSION

We showed a significant reduction in impedance of pulmonary venous flow, represented by pulmonary vein pulsatility index, during fetal respiratory movements, reflecting modifications of the left atrial dynamics and enhancement of left ventricular compliance.