Diagnostic Value of Color Flow Mapping and Doppler Echocardiography in the Quantification of Mitral Regurgitation in Patients with Mitral Valve Prolapse or Rheumatic Heart Disease

Multi-Modality Imaging in the Evaluation and Treatment of Mitral Regurgitation

OPINION STATEMENT

Mitral regurgitation (MR) is frequent and associated with increased mortality and morbidity when severe. It may be caused by intrinsic valvular disease (primary MR) or ventricular deformation (secondary MR). Imaging has a critical role to document the severity, mechanism, and impact of MR on heart function as selected patients with MR may benefit from surgery whereas other will not. In patients planned for a surgical intervention, imaging is also important to select candidates for mitral valve (MV) repair over replacement and to predict surgical success. Although standard transthoracic echocardiography is the first-line modality to evaluate MR, newer imaging modalities like three-dimensional (3D) transesophageal echocardiography, stress echocardiography, cardiac magnetic resonance (CMR), and computed tomography (CT) are emerging and complementary tools for MR assessment. While some of these modalities can provide insight into MR severity, others will help to determine its mechanism. Understanding the advantages and limitations of each imaging modality is important to appreciate their respective role for MR assessment and help to resolve eventual discrepancies between different diagnostic methods. With the increasing use of transcatheter mitral procedures (repair or replacement) for high-surgical-risk patients, multimodality imaging has now become even more important to determine eligibility, preinterventional planning, and periprocedural guidance.

Criteria for mitral regurgitation classification were inadequate for dilated cardiomyopathy

Background

Mitral regurgitation (MR) is common in patients with dilated cardiomyopathy (DCM). It is unknown whether the criteria for MR classification are inadequate for patients with DCM.

Objective

We aimed to evaluate the agreement among the four most common echocardiographic methods for MR classification.

Methods

Ninety patients with DCM were included. Functional MR was classified using four echocardiographic methods: color flow jet area (JA), vena contracta (VC), effective regurgitant orifice area (ERO) and regurgitant volume (RV). MR was classified as mild, moderate or important according to the American Society of Echocardiography criteria and by dividing the values into terciles. The Kappa test was used to evaluate whether the methods agreed, and the Pearson correlation coefficient was used to evaluate the correlation between the absolute values of each method.

Results

MR classification according to each method was as follows: JA: 26 mild, 44 moderate, 20 important; VC: 12 mild, 72 moderate, 6 important; ERO: 70 mild, 15 moderate, 5 important; RV: 70 mild, 16 moderate, 4 important. The agreement was poor among methods (kappa = 0.11; p < 0.001). It was observed a strong correlation between the absolute values of each method, ranging from 0.70 to 0.95 (p < 0.01) and the agreement was higher when values were divided into terciles (kappa = 0.44; p < 0.01)

Conclusion

The use of conventional echocardiographic criteria for MR classification seems inadequate in patients with DCM. It is necessary to establish new cutoff values for MR classification in these patients.

Usefulness of left ventricular systolic dyssynchrony by real-time three-dimensional echocardiography to predict long-term response to cardiac resynchronization therapy

Real-time 3-dimensional echocardiography (RT3DE) allows simultaneous timing of regional volumetric changes as a net result of longitudinal, radial, circumferential left ventricular (LV) contraction, hence LV systolic dyssynchrony. We sought to examine real-time 3-dimensional echocardiographically derived dyssynchrony for prediction of long-term response to cardiac resynchronization therapy (CRT) in a prospective study. Ninety consecutive patients with heart failure (mean age 60 +/- 12 years, 73% men, New York Heart Association class III in 97%) underwent clinical and echocardiographic assessments at baseline and at 12 months after CRT including real-time 3-dimensional echocardiographically derived LV systolic dyssynchrony index. The systolic dyssynchrony index (SDI) was defined as the SD of time to minimum systolic volume of the 16 LV segments, expressed in percent RR duration. CRT response was defined as a >15% decrease in LV end-systolic volume on real-time 3-dimensional echocardiogram. After 12 months of CRT, 68 patients (76%) were responders. Feasibility of the SDI was 94%. An SDI >10% predicted CRT response with good sensitivity (96%), specificity (88%), positive likelihood ratio (8), and negative likelihood ratio (0.05). Patients with an SDI >10% had mean change (-21%, -31%, 39% vs -13%, -10%, 10%) in LV end-diastolic volume, LV end-systolic volume, and LV ejection fraction, respectively, compared with baseline versus patients with an SDI <10% (p <0.01). Mean acquisition and analysis duration of single-patient RT3DE was 8 minutes (range 6 to 13). Interobserver variabilities of LV end-systolic volume and SDI were 5% and 11%, respectively. In conclusion, RT3DE provides accurate identification of reverse volumetric LV remodeling after CRT. From these accurate volumetric data, RT3DE provides more intuitive assessment of dyssynchrony and response to CRT as a simple, reproducible, and fast technique. CRT can be individually tailored using RT3DE and seems very effective in patients with heat failure with real-time 3-dimensional echocardiographic evidence of dyssynchrony.