Investigation of the correlation between cardiac parameters and aortic diameter in patients with ascending aortic aneurysm

Background Aortic aneurysms (AA) are enlargement of the aorta silently until diagnosing, not detectable on physical examination, and usually incidentally discovered during radiologic scanning for other reasons. It can get bigger sizes and can result in life-threatening outcomes if not detected early on. In this study, we aimed to determine the relationship between ascending aortic diameter and cardiac parameters that can be detected with tomography or/and echocardiography. Newly diagnosed (n: 85) ascending AA patients and healthy individuals (n: 86) who have not any thoracic pathology in computed tomography (CT) scans included to the study. Echocardiographically determined left atrial dimension (LAD), left ventricular end-diastolic diameter (LVDd), left ventricular end-systolic diameter (LVDs), left ventricular ejection fraction (LVEF) and the left ventricular posterior wall thickness (LVPWd) values of each patient were recorded. The thorax diameters, ascending aorta diameters and cardiac volume values recorded from CT scans. The obtained findings were statistically compared. Results Positive correlation was found between aortic diameter and aging (p: 0.000). Increased thorax diameter and cardiac volume values were detected in ascending AA cases (p < 0.05). It was found to be ascending aortic diameter was positively correlated with thorax diameter and cardiac volume (0.50 < r ≤ 0.70) values and higher aortic diameter, cardiac volume, thorax diameter values were detected in male individuals when compared with the female gender. There was no significant correlation between LVEF, LVDd, and LVDs values and aortic diameter. Conclusions Cardiac volume and thorax diameter were found as strongly correlated with the diameter of the ascending aorta. The clarifying of these parameters with larger cohorts might be beneficial for the estimation of the progression of ascending AA.

Correlation between Volumes Determined by Echocardiography and Cardiac MRI in Controls and Atrial Fibrillation Patients

Aims: We aimed to compare cardiac volumes measured with echocardiography (echo) and cardiac magnetic resonance imaging (MRI) in a mixed cohort of healthy controls (controls) and patients with atrial fibrillation (AF). Materials and methods: In total, 123 subjects were included in our study; 99 full datasets were analyzed. All the participants underwent clinical evaluation, EKG, echo, and cardiac MRI acquisition. Participants with full clinical data were grouped into 63 AF patients and 36 controls for calculation of left atrial volume (LA Vol) and 51 AF patients and 30 controls for calculation of left ventricular end-diastolic volume (LV EDV), end-systolic volume (ESV), and LV ejection fraction (LV EF). Results: No significant differences in LA Vol were observed (p > 0.05) when measured by either echo or MRI. However, echo provided significantly lower values for left ventricular volume (p < 0.0001). The echo LA Vol of all the subjects correlated well with that measured by MRI (Spearmen correlation coefficient r = 0.83, p < 0.0001). When comparing the two methods, significant positive correlations of EDV (all subjects: r = 0.55; Controls: r = 0.71; and AF patients: r = 0.51) and ESV (all subjects: r = 0.62; Controls: r = 0.47; and AF patients: r = 0.66) were found, with a negative bias for values determined using echo. For a subgroup of participants with ventricular volumes smaller than 49.50 mL, this bias was missing, thus in this case echocardiography could be used as an alternative for MRI. Conclusion: Good correlation and reduced bias were observed for LA Vol and EF determined by echo as compared to cardiac MRI in a mixed cohort of patients with AF and healthy volunteers. For the determination of volume values below 49.50 mL, an excellent correlation was observed between values obtained using echo and MRI, with comparatively reduced bias for the volumes determined by echo. Therefore, in certain cases, echocardiography could be used as a less expensive, less time-consuming, and contraindication free alternative to MRI for cardiac volume determination.

Oxytocin Protects Against Isoproterenol-Induced Cardiac Hypertrophy by Inhibiting PI3K/AKT Pathway via a lncRNA GAS5/miR-375-3p/KLF4-Dependent Mechanism

Cardiac hypertrophy is caused by cardiac volume or pressure overload conditions and ultimately leads to contractile dysfunction and heart failure. Oxytocin (OT), an endocrine nonapeptide, has been identified as a cardiovascular homeostatic hormone with anti-hypertrophic effects. However, the underlying mechanism remains elusive. In this study, we aimed to investigate the role and mechanism of OT in cardiac hypertrophy. The rats with cardiac hypertrophy induced by isoproterenol (ISO) were treated with or without oxytocin. Cardiac functional parameters were analyzed by echocardiography. The changes in cell surface area were observed using wheat germ agglutinin (WGA) or immunofluorescence staining. The expressions of cardiac hypertrophy markers (B-Natriuretic Peptide, BNP and β-myosin heavy chain, β-MHC), long non-coding RNA Growth (LcRNA) Arrest-Specific transcript 5 (lncRNA GAS5), miR-375-3p, and Kruppel-like factor 4 (Klf4) were detected by qRT-PCR. KLF4 protein and PI3K/AKT pathway related proteins were detected by Western blot. The interactions among lncRNA GAS5, miR-375-3p, and Klf4 were verified by dual-luciferase reporter assays. The findings showed that OT significantly attenuated cardiac hypertrophy, increased expressions of lncRNA GAS5 and KLF4, and decreased miR-375-3p expression. In vitro studies demonstrated that either knock-down of lncRNA GAS5 or Klf4, or over-expression of miR-375-3p blunted the anti-hypertrophic effects of OT. Moreover, down-regulation of lncRNA GAS5 promoted the expression of miR-375-3p and inhibited KLF4 expression. Similarly, over-expression of miR-375-3p decreased the expression of KLF4. Dual-luciferase reporter assays validated that lncRNA GAS5 could sponge miR-375-3p and Klf4 was a direct target gene of miR-375-3p. In addition, OT could inactivate PI3K/AKT pathway. The functional rescue experiments further identified OT regulated PI3K/AKT pathway through lncRNA GAS5/miR-375-3p/KLF4 axis. In summary, our study demonstrates that OT ameliorates cardiac hypertrophy by inhibiting PI3K/AKT pathway via lncRNA GAS5/miR-375-3p/KLF4 axis.

Temporal Registration of Cardiac Multimodal Images Using Locally Linear Embedding Algorithm

Purpose: Multimodal Cardiac Image (MCI) registration is one of the evolving fields in the diagnostic methods of Cardiovascular Diseases (CVDs). Since the heart has nonlinear and dynamic behavior, Temporal Registration (TR) is the fundamental step for the spatial registration and fusion of MCIs to integrate the heart's anatomical and functional information into a single and more informative display. Therefore, in this study, a TR framework is proposed to align MCIs in the same cardiac phase. Materials and Methods: A manifold learning-based method is proposed for the TR of MCIs. The Euclidean distance among consecutive samples lying on the Locally Linear Embedding (LLE) of MCIs is computed. By considering cardiac volume pattern concepts from distance plots of LLEs, six cardiac phases (end-diastole, rapid-ejection, end-systole, rapid-filling, reduced-filling, and atrial-contraction) are temporally registered. Results: The validation of the proposed method proceeds by collecting the data of Computed Tomography Coronary Angiography (CTCA) and Transthoracic Echocardiography (TTE) from ten patients in four acquisition views. The Correlation Coefficient (CC) between the frame number resulted from the proposed method and manually selected by an expert is analyzed. Results show that the average CC between two resulted frame numbers is about 0.82±0.08 for six cardiac phases. Moreover, the maximum Mean Absolute Error (MAE) value of two slice extraction methods is about 0.17 for four acquisition views. Conclusion: By extracting the intrinsic parameters of MCIs, and finding the relationship among them in a lower-dimensional space, a fast, fully automatic, and user-independent framework for TR of MCIs is presented. The proposed method is more accurate compared to Electrocardiogram (ECG) signal labeling or time-series processing methods which can be helpful in different MCI fusion methods.

Performance of Fetal Cardiac Volume Derived from VOCAL (Virtual Organ Computer-Aided AnaLysis) in Predicting Hemoglobin (Hb) Bart’s Disease

Objective: To determine the performance of fetal cardiac volume (CV) in the detection of fetal Hb Bart’s disease among fetuses at risk at 18–22 weeks of gestation and to compare the performance with those of cardiothoracic diameter ratio (CTR) and middle cerebral artery peak systolic velocity (MCA-PSV). Methods: Fetuses at risk of Hb Bart’s disease between 18 and 22 weeks of gestation prospectively underwent echocardiography with acquisition of the volume datasets (VDS) of fetal heart, using 4D-cardiac STIC. Subsequently, off-line analysis was blindly performed to measure cardiac volume using the VOCAL technique. Results: A total of 502 fetuses at risk meeting the inclusion criteria were included in the analysis, consisting of 117 (23.3%) fetuses with Hb Bart’s disease and 385 (76.7%) unaffected fetuses. The mean (±SD) gestational age at the time of ultrasound examination was 19.70 ± 1.3 weeks. In predicting fetal Hb Bart’s disease, CV, using a cut-off Z-score of 1.7, had a sensitivity of 94.9% and specificity of 94.0%. The performance of CV was slightly better than that of CTR but very superior to that of MCA-PSV (areas under curve: 0.988, 0.974 and 0.862, respectively). Conclusions: Fetal CV has a very high performance in predicting fetal Hb Bart’s disease at mid-pregnancy, comparable with CTR and much better than MCA-PSV.

Abstract P193: Effect Of Nitroglycerin And Sympathetic Withdrawal On Splanchnic Capacitance And Cardiac Blood Volumes

The splanchnic vasculature is the largest blood volume reservoir in the human body. Reduced capacitance of this vascular bed, in part due to sympathetic venoconstriction, is proposed to play a role in hypertension and heart failure. Thus, interventions that increase splanchnic capacitance or decrease sympathetic activity may be beneficial in these conditions. In a proof-of-concept study in healthy and hypertensive subjects, we evaluated whether venodilation with nitroglycerin (NTG; Study 1) or sympathetic withdrawal with trimethaphan (Study 2) increase splanchnic capacitance and reduce cardiac and stroke volumes. In Study 1 (n=10, 36±4 yrs, BMI 26.1±1.7, 4 men), abdominal and chest scintigrams, to measure regional blood volumes, were obtained before and after 0.6 mg sublingual NTG. Splanchnic capacitance (volume-pressure relationships, VPR) and compliance (VPR slope) were estimated by recording abdominal scintigrams during progressive escalation of intrathoracic pressure using continuous positive airway pressure (CPAP) at 0, 4, 8, 12, and 16 cm H 2 O, each for ≤2 min. We found that NTG increased splanchnic blood volume at rest (4%, IQR 1.81-9.95; P<0.01) resulting in a rightward parallel shift in splanchnic VPR (P slope =0.46 and P intercept =0.01), indicating an increase in splanchnic capacitance. This was associated with a decrease in cardiac blood volume (-9%, IQR 2.2-10.3; P<0.01). In Study 2, we measured blood pressure (BP) and stroke volume, used as a surrogate of venous return, during the same CPAP protocol before and during autonomic blockade with trimethaphan in 12 hypertensive subjects (49±2 yrs, BMI 29.9±1.7, 5 men). Sympathetic withdrawal decreased systolic BP (-27±14 mmHg) and produced a leftward parallel shift in VPR (i.e. reduced stroke volume; P slope =0.12 and P intercept <0.01), indicating a reduction in venous return likely due to an increase in splanchnic capacitance. In conclusion, venodilation with NTG increased splanchnic capacitance and decreased cardiac volume. Sympathetic withdrawal had similar hemodynamic effects. These findings highlight the importance of splanchnic capacitance in cardiovascular regulation.

Analysis of Ultrasonic Features Based on Absence of Pulmonary Artery

According to clinical features and ultrasonic imaging features of patients with absence of pulmonary artery, it is necessary to analyze ultrasonic imaging features of absence of pulmonary artery to provide clinical basis for improving the diagnostic value and prognosis. The data and color Doppler echocardiography of 45 patients with absence of pulmonary artery are collected, who are confirmed by cardiac catheterization, CTA and operation, and the clinical features and ultrasonic imaging features are studied. The research results show that 57% of the patients have left absence of pulmonary artery and 91% of them have other cardiovascular malformations, where ASD/PFO is the most common, PDA and VSD are the second. Patients with UAPA have changes of pulmonary artery, the incidence of pulmonary artery abnormalities in multiple malformations, changes of ASD/PFO, PDA and VSD are mainly pulmonary hypertension. The ejection fraction of patients with UAPA is normal. The main manifestation of pulmonary hypertension is the increase of right cardiac volume load, and the main manifestation of pulmonary stenosis is the increase of collateral circulation. Pulmonary hypertension and its associated cardiovascular malformations may be related to the prognosis of patients. Ultrasound doctors should understand such diseases to improve the diagnosis rate and the prognosis.