Subclinical systolic dysfunction detected by 2D speckle tracking echocardiography in adults with diabetes mellitus: systematic review and meta-analysis of 6668 individuals with diabetes mellitus and 7218 controls.

PURPOSE: Speckle tracking echocardiography (STE) can help to identify subclinical features of diabetic cardiomyopathy (DCM). There is, however, significant heterogeneity in the reported strain values in literature. We performed a systematic review and meta-analysis to compare cardiac systolic strain values assessed by 2D-STE in asymptomatic adults with diabetes mellitus (DM) and healthy controls. METHODS: Five databases were searched, and a total of 41 valid studies (6668 individuals with DM and 7218 controls) were included for analysis. Pooled mean in each group and mean difference (MD) for left ventricular global longitudinal strain (LVGLS), LV global circumferential strain (LVGCS), LV global radial strain (LVGRS), LV longitudinal systolic strain rate (LVSR), left atrial reservoir strain (LARS) and right ventricular GLS (RVGLS) were assessed. RESULTS: Patients with DM had overall 2 units lower LVGLS than healthy subjects 17.5% [16.8, 18.3], vs 19.5 [18.7, 20.4], MD = - 1.96 [- 2.27, - 1.64]. Other strain values were also lower in patients with DM: LVGCS (MD = - 0.89 [- 1.26, - 0.51]); LVGRS (MD = - 5.03 [- 7.18, - 2.87]); LVSR (MD = - 0.06 [- 0.10, - 0.03]); LARS (MD = - 8.41 [- 11.5, - 5.33]); and RVGLS (MD = - 2.41 [- 3.60, - 1.22]). Meta-regression identified higher body mass index (BMI) as the single contributor to worse LVGLS, LVGCS and LVSR. Those with higher Hemoglobulin A1c had worse RVGLS. CONCLUSION: Myocardial strains were reduced in whole heart in patients with DM. The largest reduction was observed in LA reservoir strain, followed by RVGLS and LVGLS. Higher BMI in patients with DM is associated with worse LV strain values.

Normal Ranges of Global Left Ventricular Myocardial Work Indices in Adults: A Meta-Analysis.

BACKGROUND: Recent studies have demonstrated that left ventricular myocardial work (MW) is incremental in diagnosis and prognostication compared with left ventricular ejection fraction and myocardial strain. The authors performed a meta-analysis of normal ranges of noninvasive MW indices including global work index, global constructive work, global wasted work, and global work efficiency and determined confounders that may contribute to variance in reported values. METHODS: Four databases (PubMed, Scopus, Embase, and the Cochrane Library) were searched through January 2021 using the key terms "myocardial work," "global constructive work," "global wasted work," "global work index," and "global work efficiency." Studies were included if the articles reported LV MW using two-dimensional transthoracic echocardiography in healthy normal subjects, either in a control group or comprising the entire study cohort. The weighted mean was estimated by using the random-effect model with a 95% CI. Heterogeneity across included studies was assessed using the I2 test. Funnel plots and the Egger regression test were used to assess potential publication bias. RESULTS: The search yielded 476 articles. After abstract and full-text screening, we included 13 data sets with 1,665 patients for the meta-analysis. The reported normal mean values of global work index and global constructive work among the studies were 2,010 mm Hg% (95% CI, 1,907-2,113 mm Hg%) and 2,278 mm Hg% (95% CI, 2,186-2,369 mm Hg%), respectively. Mean global wasted work was 80 mm Hg% (95% CI, 73-87 mm Hg%), and mean global work efficiency was 96.0% (95% CI, 96%-96%). Furthermore, gender significantly contributed to variations in normal values of global work index, global wasted work, and global work efficiency. No evidence of significant publication bias was observed. CONCLUSIONS: In this meta-analysis, the authors provide echocardiographic reference ranges for noninvasive indices of MW. These normal values could serve as a reference for clinical and research use.

Three-Dimensional Global Left Ventricular Myocardial Strain Reduced in All Directions in Subclinical Diabetic Cardiomyopathy: A Systematic Review and Meta-Analysis.

Background Three-dimensional (3D) speckle tracking echocardiography can identify subclinical diabetic cardiomyopathy without geometric assumption and loss of speckle from out-of-plane motions. There is, however, significant heterogeneity among the previous reports. We performed a systematic review and meta-analysis to compare 3D strain values between adults with asymptomatic, subclinical diabetes mellitus (ie, patients with diabetes mellitus without known clinical manifestations of cardiac disease) and healthy controls. Methods and Results After systematic review of 5 databases, 12 valid studies (544 patients with diabetes mellitus and 489 controls) were eligible for meta-analysis. Pooled means and mean difference (MD) using a random-effects model for 3D global longitudinal, circumferential, radial, and area strain were calculated. Patients with diabetes mellitus had an overall 2.31 percentage points lower 3D global longitudinal strain than healthy subjects (16.6%, 95% CI, 15.7-17.6 versus 19.0; 95% CI, 18.2-19.7; MD, -2.31, 95% CI, -2.72 to -2.03). Similarly, 3D global circumferential strain (18.9%; 95% CI, 17.5-20.3 versus 20.5; 95% CI, 18.9-22.1; MD, -1.50; 95% CI, -2.09 to -0.91); 3D global radial strain (44.6%; 95% CI, 40.2-49.1 versus 48.2; 95% CI, 44.7-51.8; MD, -3.47; 95% CI, -4.98 to -1.97), and 3D global area strain (30.5%; 95% CI, 29.2-31.8 versus 32.4; 95% CI, 30.5-34.3; MD, -1.76; 95% CI, -2.74 to -0.78) were also lower in patients with diabetes mellitus. Significant heterogeneity was noted between studies for all strain directions (inconsistency factor [I2], 37%-78%). Meta-regression in subgroup analysis of studies using the most popular vendor found higher prevalence of hypertension as a significant contributor to worse 3D global longitudinal strain. Higher hemoglobulin A1c was the most significant contributor to worse 3D global circumferential strain in patients with diabetes mellitus. Conclusions Three-dimensional myocardial strain was reduced in all directions in asymptomatic diabetic patients. Hypertension and hemoglobin A1c were associated with worse 3D global longitudinal strain and 3D global circumferential strain, respectively. Registration URL: https://www.crd.york.ac.uk/prospero; unique identifier: CRD42020197825.

Pooled summary of native T1 value and extracellular volume with MOLLI variant sequences in normal subjects and patients with cardiovascular disease.

T1 mapping by cardiac magnetic resonance (CMR) allows detection of abnormal myocardium. A number of myocardial abnormalities affects the signal captured in T1 mapping. We performed a systematic review and meta-analysis of native T1 and extracellular volume (ECV) in subjects with and without cardiac disease (1) to determine the normal ranges of T1 values and ECV by sequences as well as parameters influencing them, and (2) to summarize the differences in T1 values and ECV of the diseases relative to the normal ranges. Three databases (EMBASE, SCOPUS, and MEDLINE) were systematically searched for native T1 time and ECV. Only human studies with a sample size of ≥ 20 subjects were included. A random effect model was used to pool data. The 69 selected articles included 1954 healthy subjects and 3186 with disease. T1 of normal healthy was different among MOLLI variants: in 1.5T sequences, ShMOLLI had the shortest (944 ms [95% confidence interval 925, 963]), followed by MOLLI 3(3)3(3)5 flip-angle 50°, 967 [959, 975] and flip-angle 35°, 969 [951, 988]. 3T had longer T1 than 1.5T by approximately 100-200 ms. ECV of the normal healthy was consistent among the studies (ranging from 25 to 27%), irrespective of subjects' factors, sequences, vendors, and contrast type. Many diseases demonstrated longer native T1 than normal subjects, but T1 was shorter in Fabry disease and iron overload. In contrast, all disease states showed either normal or increased ECV. Diagnostic accuracy of native T1 time was minimally affected by the difference in the sequences. ECV is less influenced by methodology than T1 time among normal subjects. Different myocardial diseases are associated with shorter or longer T1 times, whereas ECV is consistently increased independent of the underlying pathophysiology.

Air pollution and telomere length: a systematic review of 12,058 subjects.

BACKGROUND: Over recent decades, adverse effects of ambient air pollution on the cardiovascular system have been clearly demonstrated. However, the underlying mechanisms are not fully elucidated. Air pollution may accelerates biological aging and thereby the susceptibility to cardiovascular diseases (CVDs). Telomeres are tandem repetitive DNA complexes that play a critical role in maintaining chromosome stability. There are, however, heterogeneities among the reported effects of air pollution on telomere. This study sought to evaluate the existing literature on the association between air pollution and telomere length (TL). METHODS: Two reviewers independently searched on electronic databases including PUBMED, EMBASE, SCOPUS, WEB OF SCIENCE and Ovid. The key terms were "air pollution" and "telomere" without language restriction. Articles relating to tobacco smoke were excluded. RESULTS: A total of 12,058 subjects from 25 articles remained for final review. All were observational studies: 14 cross-sectional, 6 cohort and 5 case-control studies. Nineteen (76%) assessed leukocyte telomere length (LTL) of which 15 found associations between air pollution and shorter TL, 2 with longer TL, 1 had mixed results, and a study of patients with type 2 diabetes found non-significant associations with TL. One found longer TL from saliva. The remaining studies were of placental cells, buccal cells or sperm and all reported shorter TL associated with air pollution. Particulate matter (PM) was investigated in 8 articles, and the remainder assessed black carbon (BC), benzene, lead, cadmium and polycyclic aromatic hydrocarbon (PAH). Geographically, 11 studies were conducted in Europe, with 10 in Asia and 4 in North America. While all followed Cawthon's protocol for TL assessment, discordance in the reporting formats did not allow us to perform a quantitative meta-analysis. CONCLUSIONS: Most of the studies support the association of shorter TL with air pollution. Uniform reporting format would be warranted for future studies to estimate true effect size of air pollution on TL.

MRI-Derived Myocardial Strain Measures in Normal Subjects.

OBJECTIVES: The aim of this study was to perform a systematic review and meta-analysis to estimate the normal ranges of magnetic resonance imaging (MRI)-based feature tracking (FT) and to identify sources of variations. Similar analyses were also performed for strain encoding, displacement encoding with stimulated echoes, and myocardial tagging. BACKGROUND: MRI-FT is a novel technique for quantification of myocardial deformation using MRI cine images. However, the reported 95% confidence intervals (CIs) from the 2 largest studies have no overlaps. METHODS: Four databases (EMBASE, SCOPUS, PUBMED, and Web of Science) were systematically searched for MRI strains of the left (LV) and right (RV) ventricles. The key terms for MRI-FT were "tissue tracking," "feature tracking," "cardiac magnetic resonance," "cardiac MRI," "CMR," and "strain." A random effects model was used to pool LV global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS), and RVGLS. Meta-regressions were used to identify the sources of variations. RESULTS: 659 healthy subjects were included from 18 papers for MRI-FT. Pooled mean of LVGLS was -20.1% (95% CI: -20.9% to -19.3%), LVGCS -23% (95% CI: -24.3% to -21.7%), LVGRS 34.1% (95% CI: 28.5% to 39.7%), and RVGLS -21.8% (95% CI: -23.3% to -20.2%). Although there were no publication biases except for LVGCS, significant heterogeneities were found. Meta-regression showed that variation of LVGCS was associated with field strength (ß = 3.2; p = 0.041). Variations of LVGLS, LVGRS, and RVGLS were not associated with any of age, sex, software, field strength, sequence, LV ejection fraction, or LV size. LVGCS seems the most robust in MRI-FT. Among the MRI-derived strain techniques, the normal ranges were mostly concordant in LVGLS and LVGCS but varied substantially in LVGRS and RVGLS. CONCLUSIONS: The pooled means of 4 MRI-derived myocardial strain methods in normal subjects are demonstrated. Differences in field strength were attributed to variations of LVGCS.