Dimitrios Maragiannis

Functional 3D Printed Patient-Specific Modeling of Severe Aortic Stenosis

Computed tomography (CT) provides high-resolution images of the aortic valve with clear localization of calcium deposition. Three-dimensional (3D) stereolithographic printing can be used to convert these data into a physical model [(1,2)][1]. We hypothesized that patient-specific, multimaterial, 3D

Comparative Assessment of Mitral Regurgitation Severity by Transthoracic Echocardiography and Cardiac Magnetic Resonance Using an Integrative and Quantitative Approach

Although transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) are validated in quantitation of mitral regurgitation (MR), discrepancies may occur. This study assesses the agreement between TTE and CMR in MR and evaluates characteristics and clinical outcome of patients with discrepancy. From our institutional database, 70 subjects with MR underwent both TTE and CMR within 30 days (median 3 days). MR was evaluated semiquantitatively (n = 70) using a 4-grade scale and quantitatively (n = 60) with calculation of regurgitant volume (RVol) and regurgitant fraction (RF). Of the 70 subjects, qualitative assessment by TTE yielded 30 subjects with mild MR, 17 moderate, and 23 moderately severe or severe MR. Exact concordance in MR grade was seen in 50% and increased to 91% when considering concordance within one grade of severity (κ = 0.44). A modest correlation was observed for RVol and RF between both methods (r = 0.59 and 0.54, respectively, p <0.0001). Ten patients had a significant discrepancy in quantitative MR (difference in RF >20%); the frequency of secondary MR was higher (100% vs 46%; p = 0.003) in patients with discrepancy. Although interobserver variability in RF was higher with TTE compared with CMR (-5.5 ± 15% vs 0.1 ± 7.3%), patients with discrepancy were equally distributed by severity and clinical outcome without an overestimation by either method. In conclusion, there is a modest agreement between TTE and CMR in assessing MR severity. In patients with discrepancy, there is a higher prevalence of functional MR, without a consistent overestimation of MR severity by either method.

Echocardiographic Evaluation of Left Ventricular Diastolic Function: an Update

Echocardiographic evaluation of diastolic properties and assessment of hemodynamic status of the right and the left ventricle have been traditionally applied for many years in clinical practice. Establishment of diagnosis of diastolic dysfunction, grading, and estimation of filling pressures noninvasively adds prognostic information to the clinician, which may affect treatment management. Novel methods, including left atrium strain, left ventricular diastolic strain rate, and left ventricular untwisting rate, have been imported in clinical practice attempting to provide a more comprehensive and more accurate understanding of the mechanisms and diagnosis of diastolic dysfunction.

Clinical Utility of Multidetector Computed Tomography in Redo Valve Procedures.

Transesophageal echocardiography (TEE) is recommended for diagnosis in patients suspected of prosthetic valve dysfunction, but could be limited in its ability to identify the etiology of these dysfunctions and to assess extracardiac structures. Our objective is to examine the usefulness of multidetector computed tomography (MDCT) in establishing the etiology of the dysfunctions and its clinical utility in preoperative assessment in these patients.

Vortex Formation Time Index in Patients With Hypertrophic Cardiomyopathy

Vortex ring formation in early diastole helps with left ventricular (LV) filling without an increase in left atrial (LA) pressure. Vortex formation time (VFT) is a dimensionless parameter derived from LV geometry and indexes of LV systolic and diastolic performance [(1)][1]. The optimal range was

Association of Left Ventricular Diastolic Dysfunction with Subclinical Coronary Atherosclerotic Disease Burden Using Coronary Artery Calcium Scoring.

AIM Diastolic dysfunction is a common problem in patients with obesity, hypertension, diabetes, or coronary artery disease. The purpose of this study was to evaluate the association of left ventricular diastolic dysfunction with an abnormal coronary artery calcium score (CAC score). METHODS This study considered a cohort of patients ≥ 18 years of age with normal ejection fraction who were admitted to the hospital with chest pain. All patients underwent regadenoson myocardial perfusion stress imaging and had no evidence of ischemia or infarction. Patients then underwent cardiac CT for measurement of CAC score. Patients were excluded if they had prior history of coronary artery disease, ECG findings diagnostic of an acute coronary syndrome, an elevated troponin level, or hemodynamic instability. RESULTS A total of 114 patients were included and 52 (45.6%) patients had echocardiographic evidence of diastolic dysfunction. Patients with diastolic dysfunction were more likely to have an abnormal calcium score (79.6% vs 20%; OR 15.10, 95% CI 5.70 to 43.85; p ＜ 0.001). In multivariable analysis, the presence of diastolic dysfunction on echocardiogram was significantly associated with an abnormal calcium score (OR 13.82, 95% CI 5.57 to 37.37; p ＜ 0.001) after adjusting for Framingham Risk Score or clinical risk factors (age, gender, diabetes mellitus, dyslipidemia, and obesity; OR 19.06,95% CI 4.66 to 107.97; p ＜ 0.001). CONCLUSIONS Our study demonstrates that left ventricular diastolic dysfunction is associated with an abnormal CAC score even after adjusting for Framingham Risk Score or clinical risk factors. Patients without known coronary artery disease that present with chest pain and have normal perfusion imaging with evidence of abnormal diastolic function on echocardiogram may warrant more thorough evaluation for coronary atherosclerotic disease with CAC score assessment.

Quantification of Mitral Valve Regurgitation: New Solutions Provided by 3D Echocardiography

The accurate quantification of mitral regurgitation (MR) using 2D imaging tools is difficult due to its structural complexity; however, it is crucially important in clinical medicine as MR severity has prognostic consequences. Novel 3-dimensional (3D) echocardiography and 3-dimensional (3D) color Doppler methods can provide quantitative and qualitative classification of MR including measurement of the vena contracta area, regurgitant volume, regurgitant fraction, and effective regurgitant orifice area (EROA). Nevertheless, with so many conventional and developing techniques it can be difficult to decide which technique to use for selected patients. We suggest using an approach that is focused not only on the techniques and measurements but also combines imaging portability, availability, clinical efficiency, and accurate and reproducible assessments. In this review we discuss the established and emerging applications of 3D color Doppler for the quantification of MR severity.

Interventional imaging: the role of echocardiography.

Interventional echocardiography is a rapidly evolving field requiring imaging expertise. An increasing number of structural heart interventions now require real-time imaging guidance for device placement and immediate functional evaluation. Continuous 2- and 3-dimensional transesophageal echocardiography are now required by many heart teams during complex structural interventions, including percutaneous closure of atrial septal defects, left atrial appendage occlusion, transcatheter aortic valve replacement (TAVR), transcatheter repair of paravalvular regurgitation, and percutaneous mitral valve repair. In this review, we describe the role of echocardiography during the initial structural evaluation, throughout the device placement procedure, and for the assessment of acute device function and complications.

Echocardiographic Evaluation of Tricuspid Prosthetic Valves: An Update

This review focuses on the diagnostic value of novel echocardiographic techniques and the clinical application of recently described algorithms to assess tricuspid prosthetic valve function.

An in vitro validation of cardiac magnetic resonance 4D flow measurements with bioprosthetic mitral valve flow volumes quantification

Background Four dimensional flow MRI is a new methodology for evaluating the morphology of the heart using phase contrast cardiac magnetic resonance imaging not only in the usual three dimensions (x, y and z), but also across time. The full breadth of this new form of imaging has yet to be fully established. In order to evaluate this modality and its accuracy, we decided to use 4D flow MRI to quantify diastolic flow volumes across a bioprosthetic valve (BPV) in a controlled and reproducible in vitro system. Methods Three different sizes of BMV’s (27, 29, and 31 mm) were consecutively mounted in an MRI compatible flow loop where the flow conditions could be controlled using software that programmed a pump to generate pulsatile, physiologic ventricular ejection and filling simulations. The generated pulses were generated using each valve and mimicked diastolic flow volumes of about 70, 90 and 110 ml/beat at a rate of 70 bpm. An in-series ultrasonic flow transducer (UFT) was used to measure flow (L/min) by which diastolic flow volumes were determined. The acquisition of 3D cine (4D flow) phase contrast velocity data was acquired in a 1.5 Tesla MRI scanner (Avanto, Siemens Medical Solutions, Inc., Erlangen, Germany). The typical imaging parameters were: repetition time 45-48 ms, echo time 2.75 ms, flip angle 15°, slice thickness 1.5 mm, field of view 350 × 260 mm2, voxel size 1.5 × 1 × 1.25 mm3. The flow measurements were determined at 3 locations within the valve in post-imaging examination including at the valve base, leaflet tips, and midway between the base and the tips. Results