Quantitative evaluation of longitudinal strain in layer-specific myocardium during normal pregnancy in China

Stretch-induced compliance mechanism in pregnancy-induced cardiac hypertrophy and the impact of cardiovascular risk factors

Pressure overload-induced hypertrophy compromises cardiac stretch-induced compliance (SIC) after acute volume overload (AVO). We hypothesized that SIC could be enhanced by physiological hypertrophy induced by pregnancy's chronic volume overload. This study evaluated SIC-cardiac adaptation in pregnant women with or without cardiovascular risk (CVR) factors. Thirty-seven women (1st trimester, 1stT) and a separate group of 31 (3rd trimester, 3rdT) women [healthy or with CVR factors (obesity and/or hypertension and/or with gestational diabetes)] underwent echocardiography determination of left ventricular end-diastolic volume (LVEDV) and E/e' before (T0), immediately after (T1), and 15 min after (T2; SIC) AVO induced by passive leg elevation. Blood samples for NT-proBNP quantification were collected before and after the AVO. Acute leg elevation significantly increased inferior vena cava diameter and stroke volume from T0 to T1 in both 1stT and 3rdT, confirming AVO. LVEDV and E/e' also increased immediately after AVO (T1) in both 1stT and 3rdT. SIC adaptation (T2, 15 min after AVO) significantly decreased E/e' in both trimesters, with additional expansion of LVEDV only in the 1stT. NT-pro-BNP increased slightly after AVO but only in the 1stT. CVR factors, but not parity or age, significantly impacted SIC cardiac adaptation. A distinct functional response to SIC was observed between 1stT and 3rdT, which was influenced by CVR factors. The LV of 3rdT pregnant women was hypertrophied, showing a structural limitation to dilate with AVO, whereas the lower LV filling pressure values suggest increased diastolic compliance.NEW & NOTEWORTHY The sudden increase of volume overload triggers an acute myocardial stretch characterized by an immediate rise in contractility by the Frank-Starling mechanism, followed by a progressive increase known as the slow force response. The present study is the first to characterize echocardiographically the stretch-induced compliance (SIC) mechanism in the context of physiological hypertrophy induced by pregnancy. A distinct functional adaptation to SIC was observed between first and third trimesters, which was influenced by cardiovascular risk factors.

The impact of echocardiographic indexation to evaluate cardiac reverse remodeling throughout pregnancy and postpartum

INTRODUCTION AND OBJECTIVES

Echocardiography guidelines suggest normalizing left ventricular (LV) volumes and mass (LVM) to body size. During pregnancy, continuous weight variation impacts on body surface area (BSA) calculation, limiting the longitudinal analysis of cardiac remodeling (CR) and reverse remodeling (RR) variables. Our aim was to identify the most common indexing methodologies in the literature on pregnant populations through a systematic review; and, to compare four scaling methods: (i) none (absolute values); (ii) indexing to the BSA before pregnancy; (iii) allomeric indexing; and (iv) indexing to BSA measured at the same day of cardiac assessment, using an illustrative example.

METHODS

We performed a systematic review of CR and RR during pregnancy and post-partum, using two databases. We included studies reporting longitudinal echocardiographic analysis of cardiac chamber volumes in humans. We used a prospective cohort study of healthy pregnant women who underwent four echocardiographic evaluations during pregnancy and postpartum, as an illustrative example.

RESULTS

Twenty-seven studies were included, most studies indexed to BSA measured at each evaluation moment (n=21). Within-subjects design was the most reported to analyse longitudinal data (n=17). Indexation to the pre-pregnancy BSA or application of allometric indexes revealed a higher effect than BSA measured at each evaluation and an equal effect to not indexing using within-subjects design. The within-subjects designs also revealed a higher effect size value than the between-subjects design for longitudinal analysis of LVM adaptations during pregnancy and postpartum.

CONCLUSION(S)

This study concludes that indexation methods do not impact the clinical interpretation of longitudinal echocardiographic assessment but highlights the need to harmonize normalization procedures during pregnancy.

Layer-specific fast strain-encoded cardiac magnetic resonance imaging aids in the identification and discrimination of acute myocardial injury: a prospective proof-of-concept study

BACKGROUND

Acute myocardial injury is a common diagnosis in the emergency department and differential diagnoses are numerous. Cardiac magnetic resonance (CMR) strain sequences, such as fast strain ENCoded (fSENC), are early predictors of myocardial function loss. This study assessed the potential diagnostic and prognostic benefits of a layer-specific approach.

METHODS

For this prospective study, patients in the emergency department fulfilling rule-in criteria for non-ST-elevation myocardial infarction (NSTEMI) received an ultra-fast fSENC CMR. Volunteers without cardiac diseases (controls) were recruited for comparison. Measurements were performed in a single heartbeat acquisition to measure global longitudinal strain (GLS) and segmental longitudinal strain and dysfunctional segments. The GLS was measured in two layers and a difference (GLSdifference = GLSepicardial - GLSendocardial) was calculated. The performance of those strain features was compared to standard care (physical examination, cardiac biomarkers, electrocardiogram). According to the final diagnosis after discharge, patients were divided into groups and followed up for 2 years.

RESULTS

A total of 114 participants, including 50 controls, were included. The 64 patients (51 male) were divided into a NSTEMI (25), myocarditis (16), and other myocardial injury group (23). GLS served as a potent predictor of myocardial injury (area under the curve (AUC) 91.8%). The GLSdifference provided an excellent diagnostic performance to identify a NSTEMI (AUC 83.2%), further improved by including dysfunctional segments (AUC 87.5%, p = 0.01). An optimal test was achieved by adding fSENC to standard care (AUC 95.5%, sensitivity 96.0%, specificity 86.5%, p = 0.03). No death occurred in 2 years for patients with normal GLS and ≤5 dysfunctional segments, while three patients died that showed abnormal GLS or >5 dysfunctional segments.

CONCLUSIONS

Layer-specific strain is a potential new marker with high diagnostic performance in the identification and differentiation of acute myocardial injuries.

Cardiovascular risk factors during pregnancy impact the postpartum cardiac and vascular reverse remodeling

Pregnant women with cardiovascular risk (CVR) factors are highly prone to develop cardiovascular disease later in life. Thus, recent guidelines suggest extending the follow-up period to 1 yr after delivery. We aimed to evaluate cardiovascular remodeling during pregnancy and determine which CVR factors and potential biomarkers predict postpartum cardiac and vascular reverse remodeling (RR). Our study included a prospective cohort of 76 healthy and 54 obese and/or hypertensive and/or with gestational diabetes pregnant women who underwent transthoracic echocardiography, pulse-wave velocity (PWV), and blood collection at the 1st trimester (1T) and 3rd trimester (3T) of pregnancy as well as at the 1st/6th/12th mo after delivery. Generalized linear mixed-effects models was used to evaluate the extent of RR and its potential predictors. Pregnant women develop cardiac hypertrophy, as confirmed by a significant increase in left ventricular mass (LVM). Moreover, ventricular filling pressure (E/e') and atrial volume increased significantly during gestation. Significant regression of left ventricular (LV) volume, LVM, and filling pressures was observed as soon as 1 mo postpartum. The LV global longitudinal strain worsened slightly and recovered at 6 mo postpartum. PWV decreased significantly from 1T to 3T and normalized at 1 mo postpartum. We found that arterial hypertension, smoking habits, and obesity were independent predictors of increased LVM during pregnancy and postpartum. High C-reactive protein (CRP) and low ST2/IL33-receptor levels are potential circulatory biomarkers of worse LVM regression. Arterial hypertension, age, and gestational diabetes positively correlated with PWV. Altogether, our findings pinpoint arterial hypertension as a critical risk factor for worse RR and CRP, and ST2/IL33 receptors as potential biomarkers of postpartum hypertrophy reversal.NEW & NOTEWORTHY This study describes the impact of cardiovascular risk factors (CVR) in pregnancy-induced remodeling and postpartum reverse remodeling (up to 1 yr) by applying advanced statistic methods (multivariate generalized linear mixed-effects models) to a prospective cohort of pregnant women. Aiming to extrapolate to pathological conditions, this invaluable "human model" allowed us to demonstrate that arterial hypertension is a critical CVR for worse RR and that ST2/IL33-receptors and CRP are potential biomarkers of postpartum hypertrophy reversal.

Women with peripartum cardiomyopathy have normal ejection fraction, but abnormal systolic strain, during pregnancy

We report a case series of six women with peripartum cardiomyopathy (PPCM) who incidentally underwent echocardiography prior to the clinical presentation of PPCM. For comparison, we identified controls, matched 2:1 on age, race, body mass index, gestational age, and hypertensive disorder. Among the six cases, all were diagnosed with PPCM during the post‐partum period. Pre‐PPCM echocardiograms were performed between 17.7 weeks of gestation and 13 days post‐partum. Baseline left ventricular ejection fraction and size were normal and similar to the 12 matched controls (60% ± 6.6% vs. 61.4% ± 6.3%, P = 0.63) or left ventricular end‐diastolic dimension (4.6 cm ± 0.2 cm vs. 4.5 cm ± 0.4 cm, P = 0.689). There was a trend towards a less negative (more abnormal) mean global longitudinal strain in cases compared with controls (−14% ± 4% vs. −18.3% ± 4.5%, P = 0.0658). Mean global circumferential strain was significantly less negative (more abnormal) in cases compared with controls (−21.5% ± 5% vs. −29.3% ± 7.6%, P = 0.0329). We conclude that women who develop PPCM have normal left ventricular ejection fraction during gestation preceding PPCM, indicating that the disease develops acutely in the peripartum period. Abnormal strain can be detected, however, suggesting that strain imaging could represent a screening method in populations at high risk for PPCM if confirmed in future studies.

Layer-specific strain for assessing the effect of naringin on systolic myocardial dysfunction induced by sepsis and its underlying mechanisms

OBJECTIVE

This study aimed to investigate the protective effects of naringin on myocardial deformation and oxidative responses in rats with sepsis-induced myocardial dysfunction (SIMD).

METHODS

Global and segmental layer-specific longitudinal strain (LS) was assessed by speckle tracking echocardiography. Serum levels of creatine kinase, lactate dehydrogenase, superoxide dismutase, and malondialdehyde were measured. The activity of cleaved caspase-3 was determined by immunohistochemistry. Protein expression levels of Kelch-like ECH-related protein 1 (Keap1), nuclear erythroid factor 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) were measured by western blotting.

RESULTS

Naringin inhibited the lipopolysaccharide-induced decrease in global and layer-specific LS of the left ventricle. Naringin also increased superoxide dismutase expression and decreased malondialdehyde, creatine kinase, lactate dehydrogenase, and cleaved caspase-3 expression in rats with SIMD. Furthermore, naringin increased Nrf2 and HO-1 protein expression levels, and decreased Keap1 protein expression levels in rats with SIMD.

CONCLUSION

Layer-specific LS analysis of myocardial function by speckle tracking echocardiography can reflect early changes in myocardial systolic function. Naringin may possess a protective effect through moderating lipopolysaccharide-induced myocardial oxidative stress via the Keap1/Nrf2/HO-1 pathway in rats with SIMD.

Does layer-specific strain using speckle tracking echocardiography improve the assessment of left ventricular myocardial deformation? A review

An increasing number of studies of left ventricular myocardial deformation have been published. Layer-specific strain using speckle tracking echocardiography to evaluate left ventricular function is not recommended in clinical practice. However, evaluation of myocardial mechanics using longitudinal and circumferential layer-specific strain enables the detection of subclinical impairment of myocardial deformation in various diseases. Unfortunately, normal values for longitudinal and circumferential strain have not been clearly defined. In normal subjects, layer-specific strain decreases from the endocardial to the epicardial layer, and from the apex to the base of the left ventricle. Although various studies have tried to define normal values for each layer in healthy subjects, studies with more subjects are needed. This tool has good reproducibility in terms of intraobserver and interobserver variability, but, as with monolayer strain, it has poor intervendor variability. Efforts that aim for standardization between vendors will be required before widespread use of this technique can be advocated.

Incremental prognostic value of global left atrial peak strain in women with new-onset gestational hypertension

BACKGROUND

Left atrial strain and strain rate parameters, measured by bidimensional-speckle tracking echocardiography, have been proposed as predictors of atrial fibrillation, stroke, congestive heart failure and cardiovascular death. However, they have not yet been tested in hypertensive disorders of pregnancy. The aim of this study was to assess the prognostic role of global left atrial peak strain (GLAPS) in a population of pregnant women with new-onset hypertension in a medium-term follow-up.

METHODS

Twenty-seven consecutive women with new-onset hypertension after 20 weeks pregnancy and 23 age-matched, race-matched and gestational week-matched consecutive normotensive pregnant women were enrolled in this prospective study. All participants underwent a complete echocardiographic study with bidimensional-speckle tracking echocardiography and carotid examination. At 1-year follow-up, we evaluated the occurrence of persistent hypertension.

RESULTS

In comparison with normotensive women, those hypertensive had a higher burden of cardiovascular risk factors, similar left atrial volume indexed (P = 0.14), but severely impaired left atrial strain (P < 0.0001) and strain rate values (P < 0.0001). At 1-year follow-up, persistent hypertension was documented in 59.3% of patients. At the univariate Cox analysis, the variables associated with the occurrence of the investigated outcome in all hypertensive pregnancies were SBP (hazard ratio 1.04, P = 0.04), DBP (hazard ratio 1.11, P = 0.01), mean arterial pressure (hazard ratio 1.09, P = 0.01) values and the GLAPS value (hazard ratio 0.85, P = 0.0019). The latter was significantly associated with the investigated outcome both in preeclamptic (hazard ratio 0.84, P = 0.02) and nonpreeclamptic pregnant women (hazard ratio 0.83, P = 0.04). The receiver operating characteristics curve analysis highlighted that a GLAPS value of 23.5% or less predicted persistent hypertension with sensitivity of 100% and specificity of 90.90%.

CONCLUSION

In hypertensive pregnant women a GLAPS value of 23.5% or less reveals a greater severity of atrial cardiomyopathy and might predict postpregnancy persistent hypertension.

A comprehensive echocardiographic study of the right ventricular systolic function in pregnant women with inherited thrombophilia

Impact of the gestational changes on cardiac contractility is not clearly defined. Our aim was to evaluate subtle changes of the right ventricular systolic function during pregnancy, assessed by new echocardiographic techniques, in a population tested for inherited thrombophilia. 87 pregnant women, with a mean age of 32 ± 4 years, genetically tested for inherited thrombophilia (22 with high-risk inherited thrombophilia and 65 control group) were included. All participants had four echocardiographic assessments, three during pregnancy (one in each trimester) and the forth at 6 months after giving birth. The right ventricular (RV) systolic function was assessed by fractional area change, ejection fraction (EF) by 3D echocardiography, tricuspid annular velocity by tissue Doppler, tricuspid annular plane systolic excursion, and strain by speckle tracking. Pulmonary artery pressure was estimated using the pressure gradient between right atrium and RV. Parameters of RV systolic function, at visits 2-4, had lower values compared with the first visit and were significantly lower in the high-risk thrombophilia group. Tricuspid regurgitation and pressure gradient between the right atrium and the RV had a significant increase during pregnancy for all subjects. At visit 1, there were no differences between groups, but at the next three visits there were higher values of the gradient in the high-risk thrombophilia group. High-risk inherited thrombophilia impacts the RV contractility, with higher pulmonary artery pressure. Further studies are needed to assess long-term impact on RV of high-risk inherited thrombophilia.

Behavior of fetal longitudinal myocardial fibers assessed by speckle tracking to obtain strain and strain rate values for low-risk pregnancies

Objective To analyze the behavior of fetal longitudinal myocardial fibers assessed by speckle tracking (STE) after fetal viability. Methods A cross-sectional study was performed in 156 women with normal singleton pregnancies from 22 to 31 weeks of gestation. Strain (S) and strain rate (SR) values were measured in both ventricles during the fetal cardiac cycle. The population was divided into five gestational age groups based on 2-week intervals. The correlations of maternal variables with the S and SR variables and intra-observer analysis were performed. Results There was a significant difference in the S and SR values of the left ventricle (LV) among the gestational age groups (P = 0.007). Significantly higher S and SR values were observed in early age groups demonstrating reductions in LV S and SR values at 26 weeks, followed by stabilization. For the right ventricle (RV), there was no significant difference between gestational age groups. Significant intra-observer agreement was observed for S values of the RV (P = 0.008) and LV (P = 0.0004) and SR values of the RV (P = 0.0001) and LV (P = 0.015). Conclusion Decreases in the S and SR values of the LV occurred after 26 weeks, followed by stabilization. No significant difference was observed in the S or SR value of the RV among the gestational age groups, and no significant association of any maternal variable evaluated with S and SR values was observed. Significant intra-observer agreement was obtained among the results.

Left Ventricular Layer-Specific Myocardial Strains in Children with Recovered Primary Dilated Cardiomyopathy: What Lies Beneath the Iceberg?

We aimed to detect residual cardiac dysfunction-if any-in children with recovered primary dilated cardiomyopathy (DCM) by using the left ventricular (LV) layer-specific myocardial strains. Fifty children with recovered primary DCM both clinically and echocardiographically were included as the patient group. Fifty healthy children of matched age and sex served as the control group. Echocardiographic evaluation was performed for all included children in the form of conventional echocardiography, tissue Doppler imaging (TDI), two-dimensional speckle tracking echocardiography (2D-STE), and LV layer-specific myocardial strain. Both LV systolic and diastolic functions measured by conventional echocardiography were similar in children with recovered DCM and the control group. There was a significant reduction in LV systolic and diastolic functions measured by TDI in the patient group. Moreover, there was a significant reduction of LV global longitudinal systolic strain (GLSS) by 2D-STE in children with recovered DCM. Interestingly, there was a significant reduction of LV layer-specific myocardial strain from endocardium to epicardium in children with recovered DCM compared to the healthy control. There was a significant positive correlation between different layer-specific myocardial strains and LV GLSS, LV ejection fraction, and LV peak systolic velocity. Left ventricular layer-specific myocardial strain can be a promising tool for early identifications of LV dysfunction in children with DCM. Subtle cardiac dysfunction is present in patients with recovered DCM, so long-term follow-up is recommended in these patients.

Left Ventricular Systolic Function in Pregnant Women with Inherited Thrombophilia

Objectives:The impact of the gestational changes on left ventricular contractility is not clearly defined. Our aim was to evaluate the subtle changes of left ventricular systolic function during pregnancy, assessed by new echocardiographic techniques, in a population tested for inherited thrombophilia. Material and methods:Eighty seven consecutive pregnant women, with a mean age of 32±4 years, genetically tested for inherited thrombophilia (22 with thrombophilic mutations and risk of thrombosis and 65 without significant mutations, considered as the control group) were included. All participants had four clinical and echocardiographyc visits: three during pregnancy (one in each trimester) and the forth six months after giving birth. Left ventricular (LV) systolic function was assessed from ejection fraction (EF) by 2D and 3D echocardiography, mitral annular velocities by tissue Doppler, and strain rate by 2D speckle tracking. Outcomes:There were no differences between groups for any of the echo parameters at each of the four visits. Comparing the third visit with the first one, all parameters of LV systolic function had significantly lower values at the end of pregnancy; EF decreased from 58% to 55% (2D echo), from 60% to 56% (3D TomTec), and from 58% to 55% (Auto4DLVQ), with p<0.001 for all three methods. Moreover, strain assessed by speckle traking decreased during pregnancy, with no differences between groups. In addition to this, mitral annular velocities obtained by tissue Doppler assessment decreased during the gestational period, with no differences between groups. At six months after giving birth, all values were normalized. Conclusion:During pregnancy, LV contractility has a slight decrease, with no criteria of systolic dysfunction. Thrombophilic mutations, with correct anticoagulant treatment, has no impact on LV systolic function.

Evaluation of myocardial viability in patients with acute myocardial infarction: Layer-specific analysis of 2-dimensional speckle tracking echocardiography

BACKGROUND

The value of layer-specific two-dimensional speckle tracking echocardiography (LS2D-STE) for evaluating viable myocardium (VM) in patients with acute myocardial infarction (AMI) was unclear, this study provides new insights into it and to make a comparison with dualisotope simultaneous acquisition single photon emission computed tomography ( DISA-SPECT).

METHODS

Forty hospitalized patients with AMI and left ventricular systolic dysfunction (left ventricular ejection fraction <50%) underwent LS2D-STE and DISA-SPECT before percutaneous coronary intervention (PCI). The longitudinal, circumferential, and radial peak systolic strains and the peak systolic strain rates of 3 myocardiallayers (endocardium, mid-myocardium, and epicardium), as well as the total wall thickness, were determined by LS2D-STE. Routine echocardiography was followedup at 1, 3, 6 months after PCI, with the improvement of the wall motion as the goldenstandard for evaluating VM.

RESULTS

The sensitivity, specificity and accuracy of DISA-SPECT for evaluating VM were 82.1%, 74.3%, and 79.3%, respectively. Among the layer-specific parameters, only endocardial (endo-) longitudinal strain (LS) and endo- longitudinal strain rate (LSr) were used as independent parameters for evaluating VM (P < .05), and the sensitivity, specificity and accuracy of endo-LS and endo-LSr in evaluation of VM were 77.1%, 65.4%, and 72.9% vs 72.9%, 65.4%, and 69.7%. Endo-LS and endo-LSr were superior to total wall thickness LS and LSr (AUC endo-LS 0.767 vs total-LS 0.669; endo-LSr 0.743 vs total-LSr 0.682). The parallel test and the serial test of combination of endo-LS and endo-LSr showed similar sensitivity, specificity and accuracy to DISA-SPECT (P > .05).

CONCLUSION

The endo-LS and endo-LSr analysis of LS2D-STE can evaluate the VM well, and its sensitivity, specificity and accuracy in detection of VM are similar to those of DISA-SPECT, resulting in LS2D-STE being a good option for the assessment of VM.