Assessment of late gadolinium enhancement-negative chronic total occlusion by longitudinal strain analysis using cardiac magnetic resonance imaging

Background Strain analysis has become commonly used in clinical practice in various heart diseases. Purpose To explore whether late gadolinium enhancement (LGE)-negative areas with coronary artery chronic total occlusion (CTO) appear normal when analyzed for longitudinal strain using cardiac magnetic resonance (CMR) imaging. Material and Methods A total of 16 patients and 31 healthy controls who underwent 1.5-T MR at our hospital between January 2015 and July 2017 were included in the study. The LGE-CMR of patients with CTO was negative. Left ventricular functional parameters, segmental longitudinal strain/strain rate, and perfusion parameters were measured using CVI42 software. Results For myocardial segments supplied by CTO vessels, systolic longitudinal strain rate (SLSR)was significantly lower than that of healthy controls, and diastolic longitudinal strain rate (DLSR) was significantly higher (1.19 1/s vs. 1.02 1/s; P = 0.018). Moreover, longitudinal strain (LS), SLSR, and DLSR did not differ between good and poor collateral circulation. Perfusion index of CTO territory segments was lower than non-CTO territory segments (0.20 vs. 0.22; P = 0.027). No correlation was found between longitudinal strain parameters and perfusion parameters. Conclusion Although LGE-CMR was negative in patients with CTO, the myocardial SLSR of CTO territory segments was significantly lower than that of healthy controls.

Abstract P364: Liraglutide Protects Against Angiotensin-induced Diastolic Dysfunction And Is Associated With Altered Acetyl-coa Metabolism

Background: The mechanisms underlying diastolic dysfunction remain complicated and poorly understood. Previously implicated mechanisms include increased interstitial fibrosis and oxidative damage, altered calcium handling, and mitochondrial dysfunction. In this study, we investigate changes in the cardiac metabolic profile from mice with Angiotensin-II (Ang)-induced diastolic dysfunction. Because treatment with the GLP-1 agonist liraglutide (Lira) relieves Ang-induced diastolic dysfunction, we examined altered metabolites in Ang and Ang+Lira mice to identify metabolic pathways involved. Methods: 8-wk mice were implanted with Ang pumps (1000 ng/kg/min) +/- Lira (0.2 mg/kg/day) therapy for 4 wks and compared to sham mice. Baseline and 4-wk echocardiography was performed. Hearts were collected for RNA-sequencing, Western blot, histology, radiolabeled palmitate assay, and targeted metabolomics by liquid chromatography-mass spectrometry to assess metabolic changes. Results: After Ang treatment, mice had significant diastolic dysfunction but only mild hypertrophy based on echo and histologic measures and no evidence of systolic change. Compared to sham mice, Ang mice had reduced E/A (Sham, 2.67±0.40; Ang, 1.71±0.11; p<0.05) and peak reverse longitudinal strain rate (rLSR;Sham, 8.48±0.65/s; Ang, 6.081±0.33/s; p<0.05, consistent with diastolic dysfunction. Ang+Lira mice had improved E/A (3.57±0.50, p<0.01 vs. Ang) and rLSR (8.65±0.68/s, p<0.01 vs Ang). Targeted metabolomic analysis of hearts found significantly increased accumulation of Acetyl-CoA in Ang mice (peak area 0.14±0.02) compared to sham (0.04±0.02 ,p<0.05) that is restored by Lira therapy (0.02±0.01 ,p<0.05 vs sham and Ang). A radiolabeled palmitate oxidation assay found decreased palmitate oxidation in both Ang and Ang+Lira mice compared to sham, but interestingly, also demonstrated significantly lower acid soluble metabolite oxidation in the Ang+Lira mice vs. Ang alone. Conclusions: We found that Ang-treated mice accumulate myocardial Acetyl-CoA, suggesting a defect in TCA flux. Lira resolves the increase in Acetyl-CoA and improved measures of diastolic dysfunction. This data may implicate a novel metabolic pathway in the development of diastolic disease.

A Method for Direct Estimation of Left Ventricular Global Longitudinal Strain Rate from Echocardiograms

We present a new method for measuring global longitudinal strain and global longitudinal strain rate from 2D echocardiograms using a logarithmic-transform correlation (LTC) method. Traditional echocardiography strain analysis depends on user inputs and chamber segmentation, which yield increased measurement variability. In contrast, our approach is automated and does not require cardiac chamber segmentation and regularization, thus eliminating these issues. The algorithm was benchmarked against two conventional strain analysis methods using synthetic left ventricle ultrasound images. Measurement error was assessed as a function of contrast-to-noise ratio (CNR) using mean absolute error and root-mean-square error. LTC showed better agreement to the ground truth for strain (𝑹𝟐 = 𝟎. 𝟗1) and strain rate (𝑹𝟐 = 𝟎. 85) as compared to conventional algorithms (strain (𝑹𝟐 = 𝟎. 07), strain rate (𝑹𝟐 = 𝟎. 07)) and was unaffected by CNR. A 200% increase in strain measurement accuracy was observed compared to the conventional algorithms. Subsequently, we tested the method using a 54-subject clinical cohort (20 subjects diseased with cardiomyopathy, 34 healthy controls). Our method distinguished between normal and abnormal left ventricular function with an AUC = 0.85, a 10% improvement over the conventional GLS algorithms.

Longitudinal evaluation of cardiovascular function in six healthy cats aged 1–8 years

Objectives The purpose of this study was to determine the impact of ageing on the cardiovascular system of healthy adult cats. Methods Six experimental cats were used. Echocardiography and measurements of systolic blood pressure (SBP) were performed every year for 8 years (from 1 year of age to 8 years of age) in all cats. Age-related changes to left ventricular (LV) structures, LV systolic and diastolic function, and SBP were assessed. Results There were no significant changes in LV structures and SBP. Peak longitudinal strain rate during systole was decreased at 8 years of age, and peak longitudinal strain rate during diastole was decreased from 6 years of age. Conclusions and relevance This study revealed that some measures of cardiac function recorded in six healthy cats from 1 to 8 years of age were affected as the cats got older; however, there were no structural changes or changes in measurements that are routinely assessed in clinical practice.