2.1 Study Population
This study enrolled 30 SLE patients (SLE group) treated from September
2019 to July 2020. The patients were further divided into subgroups
according to their SELENA-SLEDAI score: SELENA-SLEDAI ≤ 12
(mild-to-moderate group), SELENA-SLEDAI > 12 (severe
group). All patients met the diagnostic criteria of SLE established by
the American Rheumatology Association (ACR) in 1997. Blood samples were
obtained from all patients and laboratory investigations were performed:
complete blood count, fasting glucose, low-density lipoproteins (LDL),
anti-double stranded DNA (anti-dsDNA), complement component C3 (C3),
complement component C4 (C4) and high sensitivity-TropT (hs-TropT). At
the same time, 30 healthy people were selected as a control group. All
participants were examined using 3D-STI to obtain relevant parameters.
The inclusion and exclusion criteria are as follows: inclusion criteria:
(1) accorded with the SLE classification standard of the ACR; (2) left
ventricular ejection fraction (LVEF) > 55% in the SLE
group, and age, sex body mass index et al were matched to the control
group; (3) no cardiovascular risk factors and no history of heart
disease or other autoimmune diseases; (4) patients in the SLE group were
treated regularly and their condition was relatively stable. Exclusion
criteria: (1) coexisting hypertension, coronary heart disease, diabetes
mellitus, hyperlipidemia, valvular disease, pericardial disease, atrial
fibrillation, congenital heart disease, or kidney disease; (2) other
autoimmune diseases. All participants were informed of the aim of the
study and agreed to participate.
The participants signed an
informed consent form before the examination, and approval was obtained
from the Medical Ethics Committee.
Echocardiography
All participants underwent an
echocardiographic examination. The images were collected by ultrasound
diagnostic doctors with more than 10 years of experience. The
participant was instructed to take the left recumbent position and the
electrocardiograph was manually connected. Color Doppler ultrasonography
(GE Vivid E9, probe: 4V, frequency: 1.5–4.0 MHz) was used, and the
on-machine 3D-STI analysis software was used for post-processing. After
the patient was instructed to hold their breath to display a
two-dimensional image (clear apical four-chambers), the 4D mode was
selected, and three consecutive and stable complete cardiac cycles were
collected quickly and without interruption. The frame rate was then
adjusted to 40% of the participant’s maximal heart rate, and the image
was stored. In the 4D auto LVQ mode, the software automatically tracked
the boundaries of the left ventricular wall (endocardium and epicardium)
during the complete cardiac cycle. The following 3D routine parameters
were obtained: left ventricular
end-diastolic volume (LVEDV), left ventricular end systolic volume
(LVESV), left ventricular ejection fraction (LVEF), spherical index
(SPI), left ventricular end diastolic mass (LV EDmass), and left
ventricular end systolic mass (LV ESmass). Besides, the following 3D
strain parameters were obtained
simultaneously: global
longitudinal strain (GLS), global circumferential strain (GCS), left
ventricular twist angle (LVtw), torsion (Tor), and peak strain
dispersion (PSD), myocardial comprehensive index (MCI = GLS × LVtw).
Statistical Analysis
SPSS 22.0 software was used for statistical analysis, and
measurement data were expressed byχ ± s . Single factor
analysis of variance
(ANOVA ) was used for inter-group comparison and the LSD-tmethod was used for pairwise comparison. Receiver operating
characteristic (ROC ) curve analysis was used to evaluate the
diagnostic efficacy of the 3D-STI parameters on left ventricular
systolic function in patients with SLE, the best cut-off point was
determined, F and P values were calculated simultaneously.
The correlation between 3D-STI parameters and hs-TropT was analyzed
using Pearson’s correlation analysis.
Intra-group correlation
coefficients (ICC ) were calculated to assess repeatability
between and within observers. The difference was statistically
significant (P < 0.05).
Results
3.1 Baseline
characteristics and laboratory results
Baseline characteristics of the study population are given in Table 1:
compared with the mild-to-moderate
group, the SELENA-SLEDAI was significantly higher in the severe group
(P < 0.05). Laboratory results of the SLE patients are
given in Table 2: compared with the mild-to-moderate group, the
anti-dsDNA, C3, C4 and hs-TropT were significantly higher in the severe
group (P < 0.05).
Table1: baseline characteristics
of the study population