Chesnal D. Arepalli

Epicardial adipose tissue and coronary artery plaque characteristics

OBJECTIVE Epicardial adipose tissue (EAT) has been implicated in the pathogenesis of coronary atherosclerosis. The association of EAT volume with type of coronary artery plaque on computed tomography angiography (CTA) is not known. METHODS Coronary artery calcium (CAC) scoring and EAT volume measurement were performed on 214 consecutive patients (mean age 54+/-14 years) referred for coronary CTA. CAC was performed on non-contrast images, while EAT volume, the severity of luminal stenoses, and plaque characterization were assessed using contrast-enhanced CTA images. EAT volume was also indexed to body surface area (EAT-i). RESULTS EAT volume correlated with age, height, body mass index (BMI), and CAC score. EAT volume increased significantly with the severity of luminal stenosis (p<0.001), and in patients with no plaques, calcified, mixed, and non-calcified plaques (62+/-33mL, 63+/-22mL, 98+/-47mL, and 99+/-36mL, respectively, p<0.001). The EAT volume was significantly larger in patients with mixed or non-calcified plaques compared to patients with calcified plaques or no plaques (all p<0.01 or smaller). The trend remained significant after adjustment for traditional risk factors for coronary artery disease. In adjusted models EAT was an independent predictor of CAC [exp(B)=3.916, p<0.05], atherosclerotic plaques of any type [exp(B)=4.532, p<0.01], non-calcified plaques [exp(B)=3.849, p<0.01], and obstructive CAD [exp(B)=3.824, p<0.05]. The above results were unchanged after replacing EAT with EAT-i. CONCLUSION EAT volume was larger in the presence of obstructive CAD and non-calcified plaques. These data suggest that EAT is associated with the development of coronary atherosclerosis and potentially the most dangerous types of plaques.

Effect of intensive versus moderate lipid-lowering therapy on epicardial adipose tissue in hyperlipidemic post-menopausal women: a substudy of the BELLES trial (Beyond Endorsed Lipid Lowering with EBT Scanning).

OBJECTIVES This study sought to evaluate the effect of intensive and moderate statin therapy on epicardial adipose tissue (EAT). BACKGROUND EAT has been associated with coronary artery disease severity and outcome. It is currently unknown whether EAT volume changes over time when patients are exposed to statin therapy. METHODS Subanalysis of a randomized study of atorvastatin 80 mg/day versus pravastatin 40 mg/day for 1 year in a clinical trial designed to assess the progression of coronary artery calcium (CAC) in hyperlipidemic post-menopausal women. Patients underwent cardiac computed tomography scans at the start and end of the trial period. RESULTS Of 420 patients, 194 received atorvastatin and 226 pravastatin; the median low-density lipoprotein change was -53.3% and -28.3% with atorvastatin and pravastatin, respectively (p < 0.001). Baseline EAT correlated with age, body mass index, hypertension, diabetes mellitus, high-density lipoprotein, triglyceride levels, and CAC (p < 0.001). At the end of follow-up, EAT regressed more in the atorvastatin than in the pravastatin group (median, -3.38% vs. -0.83%, p = 0.025). The EAT percent change from baseline was significant in the atorvastatin, but not the pravastatin group (p < 0.001 and p = 0.2, respectively). There was no correlation between lipid lowering and EAT regression. CAC progressed significantly in both groups from baseline. CONCLUSIONS In hyperlipidemic post-menopausal women, statin therapy induced EAT regression, although intensive therapy was more effective than moderate-intensity therapy. This effect does not seem linked to low-density lipoprotein lowering and may be secondary to other actions of statins such as anti-inflammatory effects.

Automatic Delineation of the Myocardial Wall From CT Images Via Shape Segmentation and Variational Region Growing

Prognosis and diagnosis of cardiac diseases frequently require quantitative evaluation of the ventricle volume, mass, and ejection fraction. The delineation of the myocardial wall is involved in all of these evaluations, which is a challenging task due to large variations in myocardial shapes and image quality. In this paper, we present an automatic method for extracting the myocardial wall of the left and right ventricles from cardiac CT images. In the method, the left and right ventricles are located sequentially, in which each ventricle is detected by first identifying the endocardium and then segmenting the epicardium. To this end, the endocardium is localized by utilizing its geometric features obtained on-line from a CT image. After that, a variational region-growing model is employed to extract the epicardium of the ventricles. In particular, the location of the endocardium of the left ventricle is determined via using an active contour model on the blood-pool surface. To localize the right ventricle, the active contour model is applied on a heart surface extracted based on the left ventricle segmentation result. The robustness and accuracy of the proposed approach is demonstrated by experimental results from 33 human and 12 pig CT images.

Repair of Prosthetic Mitral Valve Paravalvular Leak Using an Off-Pump Transapical Approach

Patients who present with significant paravalvular regurgitation after mitral valve replacement remain a difficult patient population and high-risk surgical candidates. We present 3 cases of transapical closure of mitral valve paravalvular leak (PVL) after mitral valve replacement using Amplatzer closure devices (AGA Medical Corp, Plymouth, MN). All 3 patients experienced decreased regurgitation at the site of the closure as well as symptomatic improvement in their heart failure.

Cardiac Magnetic Resonance for Paravalvular Leaks in Post-Transcatheter Aortic Valve Replacement

An 80-year–old man with known coronary artery disease presented with progressively worsening shortness of breath over the past few weeks. On transthoracic echocardiography (TTE) examination he was found to have severe aortic stenosis with an aortic valve area of 0.8 cm2. Maximum aortic valve velocity was 4.25 m/s, peak gradient was 72.2 mm Hg with a mean gradient of 43.0 mm Hg, and mild aortic valve insufficiency was noted. He was deemed a surgical candidate and was randomly assigned to transcatheter aortic valve replacement (TAVR) as part of the Placement of Aortic Transcatheter Valve Trial II trial. An Edwards Sapien 29-mm XT bioprosthetic valve was placed through left-sided transfemoral access uneventfully. Within a day of the procedure, the patient reported worsening dyspnea. A postprocedural TTE revealed mild anterior and posterior paravalvular leak (PVL) by color Doppler (Figure 1 and Movie I in the online-only Data Supplement). Given the clinical and imaging findings, a higher-grade PVL was suspected, prompting further evaluation with cardiac magnetic resonance (CMR) imaging. Figure 1. Post-transcatheter aortic valve replacement transthoracic echocardiogram showing paravalvular defect and leak. A , B-mode parasternal long axis view showing 29-mm Sapien valve in the aortic position (yellow arrows). B …

Integrating Patient Digital Photographs with Medical Imaging Examinations

We introduce the concept, benefits, and general architecture for acquiring, storing, and displaying digital photographs along with medical imaging examinations. We also discuss a specific implementation built around an Android-based system for simultaneously acquiring digital photographs along with portable radiographs. By an innovative application of radiofrequency identification technology to radiographic cassettes, the system is able to maintain a tight relationship between these photographs and the radiographs within the picture archiving and communications system (PACS) environment. We provide a cost analysis demonstrating the economic feasibility of this technology. Since our architecture naturally integrates with patient identification methods, we also address patient privacy issues.

A Complete System for Automatic Extraction of Left Ventricular Myocardium From CT Images Using Shape Segmentation and Contour Evolution

The left ventricular myocardium plays a key role in the entire circulation system and an automatic delineation of the myocardium is a prerequisite for most of the subsequent functional analysis. In this paper, we present a complete system for an automatic segmentation of the left ventricular myocardium from cardiac computed tomography (CT) images using the shape information from images to be segmented. The system follows a coarse-to-fine strategy by first localizing the left ventricle and then deforming the myocardial surfaces of the left ventricle to refine the segmentation. In particular, the blood pool of a CT image is extracted and represented as a triangulated surface. Then, the left ventricle is localized as a salient component on this surface using geometric and anatomical characteristics. After that, the myocardial surfaces are initialized from the localization result and evolved by applying forces from the image intensities with a constraint based on the initial myocardial surface locations. The proposed framework has been validated on 34-human and 12-pig CT images, and the robustness and accuracy are demonstrated.

Cardiac MRI for evaluation of paravalvular leak after Transcather Aortic Valve Replacement

Background The most common complication of Transcathether Aortic Valve Replacement (TAVR) is aortic regurgitation (AR). Typically, this regurgitation is in the mild range, yet in a smaller subset AR could be in the moderate-severe range. Significant regurgitation is usually due to paravalvular leak due to undersizing of the valve or malposition inferiorly into the left ventricular outflow tract or superiorly into the aorta during deployment. Transthoracic Echocardiography (TTE) is first line test for the amount of regurgitation, but can be flawed due to poor acoustic windows and eccentricity of the paravalvular leak. Cardiac MRI (CMR) may be used to assess the aortic regurgitation when there is a discrepancy with echocardiography or imaging of the valve is in question.

Aortoiliofemoral Assessment: MRA

Transcatheter aortic valve replacement (TAVR) is an undergoing evaluation for the treatment of inoperable or high-risk severe aortic stenosis (AS) patients. Patients with symptomatic, severe AS are at high risk for conventional surgical aortic valve replacement procedures. One of the alternate ways of managing these patients is through TAVR. Several studies on post TAVR patients with a follow-up interval up to 2 years showed significant clinical benefit, improvements in exercise capacity and in quality of life. Proper patient selection is key to optimize successful clinical outcomes. A number of imaging modalities are available for patient screening. One of them is magnetic resonance imaging (MRI). MRI provides morphological information, functional status, pre-operative planning and thus plays a role in selection of patients. It is ideally suited for patients with renal insufficiency as evaluation could be done without contrast administration. MRI may prove to be a useful alternative for TAVR evaluation and is particularly beneficial to patients with underlying chronic kidney disease.

Epicardial adipose tissue measured by magnetic resonance imaging predicts abnormal adenosine stress cardiovascular magnetic resonance imaging and future adverse cardiovascular events

Background A growing body of evidence demonstrates a quantitative association between Epicardial Adipose Tissue (EAT), cardiometabolic risk factors and measures of coronary artery disease (CAD). It is still unclear, however, if EAT is predictive of abnormal functional stress tests and clinical outcomes. The aim of this study is to elucidate the relationship between the total volume of EAT, the detection of ischemia and/or infarct with Adenosine Stress Cardiovascular Magnetic Resonance imaging (AS-CMR), and combined future adverse cardiovascular events. Methods