Assessing Regurgitation Severity, Adverse Remodeling, and Fibrosis with CMR in Aortic Regurgitation.

PURPOSE OF REVIEW: Cardiac magnetic resonance (CMR) is emerging as a valuable imaging modality for the assessment of aortic regurgitation (AR). In this review, we discuss the assessment of AR severity, left ventricular (LV) remodeling, and tissue characterization by CMR while highlighting the latest studies and addressing future research needs. RECENT FINDINGS: Recent studies have further established CMR-based thresholds of AR severity and LV remodeling that are associated with adverse clinical outcomes, and lower than current guideline criteria. In addition, tissue profiling with late gadolinium enhancement (LGE) and extracellular volume (ECV) quantification can reliably assess adverse myocardial tissue remodeling which is also associated with adverse outcomes. The strengths and reproducibility of CMR in evaluating ventricular volumes, tissue characteristics, and regurgitation severity position it as an excellent modality in evaluating and following AR patients. Advanced CMR techniques for the detection of tissue remodeling have shown significant potential and merit further investigation.

Patient-specific, echocardiography compatible flow loop model of aortic valve regurgitation in the setting of a mechanical assist device.

Background: Aortic regurgitation (AR) occurs commonly in patients with continuous-flow left ventricular assist devices (LVAD). No gold standard is available to assess AR severity in this setting. Aim of this study was to create a patient-specific model of AR-LVAD with tailored AR flow assessed by Doppler echocardiography. Methods: An echo-compatible flow loop incorporating a 3D printed left heart of a Heart Mate II (HMII) recipient with known significant AR was created. Forward flow and LVAD flow at different LVAD speed were directly measured and AR regurgitant volume (RegVol) obtained by subtraction. Doppler parameters of AR were simultaneously measured at each LVAD speed. Results: We reproduced hemodynamics in a LVAD recipient with AR. AR in the model replicated accurately the AR in the index patient by comparable Color Doppler assessment. Forward flow increased from 4.09 to 5.61 L/min with LVAD speed increasing from 8,800 to 11,000 RPM while RegVol increased by 0.5 L/min (2.01 to 2.5 L/min). Conclusions: Our circulatory flow loop was able to accurately replicate AR severity and flow hemodynamics in an LVAD recipient. This model can be reliably used to study echo parameters and aid clinical management of patients with LVAD.

An Integrative, Multiparametric Approach to Mitral Regurgitation Evaluation: A Case-Based Illustration.

Echocardiography is the first-line modality for assessing mitral regurgitation (MR). In addition to evaluation of the MR jet characteristics, echocardiography can provide quantitative parameters of MR severity. This case series illustrates the importance of integrating multiple parameters in the evaluation of MR and the role of multimodality imaging. (Level of Difficulty: Advanced.).

Prosthetic Aortic Valve Regurgitation: The Story of a Missing Piece in the Puzzle.

A 65-year-old man presented with acute decompensated heart failure. He was found to have severe prosthetic aortic valve regurgitation caused by a fractured strut of a sutureless prosthetic aortic valve that embolized to the distal portion of the aorta. We highlight the importance of multimodality imaging in diagnosis and management. (Level of Difficulty: Intermediate.).

Diagnostic Value of 3-Dimensional Vena Contracta Area for the Quantification of Residual Mitral Regurgitation After MitraClip Procedure.

OBJECTIVES: The authors sought to define the feasibility and performance of 3-dimensional (3D) vena contracta area (VCA) measurement in evaluating total residual mitral regurgitation (MR) following percutaneous edge-to-edge clip (E-EC) mitral valve repair. BACKGROUND: Residual MR severity after percutaneous repair is not only a determinant of procedural success, but also a major prognostic factor. To date, no single echocardiographic method has been recommended for post-procedural MR quantification, with the evaluation currently relying on a complex, multiparametric appraisal. METHOD: The authors performed a retrospective study of patients undergoing the E-EC procedure, for which baseline and post-repair 3D color Doppler transesophageal echocardiogram datasets were available. Total VCA was recorded as the sum of individual VCAs (if more than 1) and compared with an expert multiparametric appraisal of MR severity as the reference standard. Receiver-operating characteristic analysis was performed. RESULTS: 155 patient studies were available for review. Total VCA correlated with hemodynamic parameters and was significantly reduced after E-EC. Receiver-operating characteristic analysis demonstrated a VCA threshold of 0.27 cm2 for identification of ≥moderate MR, with good diagnostic accuracy (area under the curve 0.81) and a negative predictive value of 92%. Smaller VCA was associated with clinical New York Heart Association functional class improvement at 30-day follow-up. CONCLUSIONS: Measurement of VCA is feasible using 3D color Doppler transesophageal echocardiography and provides reliable quantification of MR following E-EC transcatheter mitral valve repair.

Interobserver Variability in Applying American Society of Echocardiography/European Association of Cardiovascular Imaging 2016 Guidelines for Estimation of Left Ventricular Filling Pressure.

BACKGROUND: Assessment of left ventricular (LV) filling pressure is among the important components of a comprehensive echocardiographic report. Previous studies noted wide limits of agreement using 2009 American Society of Echocardiography/European Association of Echocardiography guidelines, but reproducibility of 2016 guidelines update in estimating LV filling pressure is unknown. METHODS: Echocardiographic and hemodynamic data were obtained from 50 patients undergoing cardiac catheterization for clinical indications. Clinical and echocardiographic findings but not invasive hemodynamics were provided to 4 groups of observers, including experienced echocardiographers and cardiology fellows. Invasively acquired LV filling pressure was the gold standard. RESULTS: In group I of 8 experienced echocardiographers from the guidelines writing committee, sensitivity for elevated LV filling pressure was 92% for all observers, and specificity was 93±6%. Fleiss κ-value for the agreement in group I was 0.80. In group II of 4 fellows in training, sensitivity was 91±2%, and specificity was 95±2%. Fleiss κ-value for the agreement in group II was 0.94. In group III of 9 experienced echocardiographers who had not participated in drafting the guidelines, sensitivity was 88±5%, and specificity was 91±7%. Fleiss κ-value for the agreement in group III was 0.76. In group IV of 7 other fellows, sensitivity was 91±3%, and specificity was 92±5%. Fleiss κ-value for the agreement in group IV was 0.89. CONCLUSIONS: There is a good level of agreement and accuracy in the estimation of LV filling pressure using the American Society of Echocardiography/European Association of Cardiovascular Imaging 2016 recommendations update, irrespective of the experience level of the observer.

Assessment of the severity of native mitral valve regurgitation.

Mitral regurgitation (MR) is a major cause of cardiovascular morbidity and mortality. MR is classified as primary (organic) if it is due to an intrinsic valve abnormality, or secondary (functional) if the etiology is because of remodeling of left ventricular geometry and/or valve annulus. Transthoracic echocardiography (TTE) is the initial modality for MR evaluation. Parameters used for the assessment of MR include valve structure, cardiac remodeling, and color and spectral Doppler. Quantitative measurements include effective regurgitant orifice area, regurgitant volume, and regurgitant fraction. Knowledge of advantages and limitations of echo-Doppler parameters is essential for accurate results. An integrative approach is recommended in overall grading of MR as mild, moderate, or severe since singular parameters may be affected by several factors. When the mechanism and/or grade of MR is unclear from the TTE or is discrepant with the clinical scenario, further evaluation with transesophageal echocardiography or cardiac magnetic resonance imaging is recommended, the latter emerging as a powerful MR quantitation tool.