What is the step-by-step process to grade the severity of Mitral Regurgitation (MR) by Transthoracic Echocardiography (TTE)?

From the Guidelines

Grading mitral regurgitation (MR) severity by transthoracic echocardiography involves a comprehensive assessment using multiple parameters, with the most recent and highest quality study 1 providing the guidelines for assessment. To grade the severity of MR, the following steps can be taken:

• Perform color Doppler imaging to visualize the regurgitant jet in the left atrium, measuring the jet area and comparing it to the left atrial area.
• Assess the vena contracta width, which is the narrowest portion of the regurgitant jet; a width <3mm indicates mild MR, 3-7mm suggests moderate MR, and >7mm indicates severe MR, as per the guidelines 1.
• Measure the effective regurgitant orifice area (EROA) using the proximal isovelocity surface area (PISA) method; an EROA <20 mm² indicates mild MR, 20-29 mm² suggests moderate MR, and ≥40 mm² indicates severe MR, as stated in the study 1.
• Calculate the regurgitant volume; <30mL suggests mild MR, 30-59mL indicates moderate MR, and ≥60mL suggests severe MR, according to the guidelines 1.
• Evaluate for supportive findings such as left atrial enlargement, pulmonary vein flow reversal, and dense continuous-wave Doppler signal. Some key parameters to consider when grading MR severity include:
• Qualitative assessment of MV morphology, color flow MR jet, flow convergence zone, and CW signal of MR jet.
• Semi-quantitative assessment of VC width, pulmonary vein flow, mitral inflow, and TVI mit/TVI Ao.
• Quantitative assessment of EROA and R Vol. It is essential to note that a comprehensive approach using multiple parameters is necessary because each measurement has limitations, and integrating these findings provides the most accurate assessment of MR severity, as emphasized in the study 1.

From the Research

Step-by-Step Process to Grade Severity of Mitral Regurgitation by Transthoracic Echocardiography

• Step 1: Data Collection
  • Collect patient data using transthoracic echocardiography (TTE) to assess mitral regurgitation (MR) severity 2, 3, 4, 5, 6
• Step 2: Proximal Isovelocity Surface Area (PISA) Method
  • Use the PISA method to calculate the effective regurgitant orifice area, a measure of MR severity 2, 4, 5
  • Consider the limitations of the PISA method, including overestimation in patients with nonoptimal flow convergence or asymmetric flow convergence regions 2, 4
• Step 3: 2D and 3D Echocardiography
  • Use 2D and 3D TTE to assess MR severity and compare the results with the PISA method 4, 5
  • Consider the advantages of 3D TTE, including improved accuracy and reduced overestimation compared to 2D TTE 4, 5
• Step 4: Quantification of Regurgitation
  • Quantify MR severity using parameters such as regurgitant volume (RVol) and regurgitant fraction 3, 4, 5, 6
  • Compare the results with cardiac magnetic resonance imaging (CMR) to validate the accuracy of TTE 5, 6
• Step 5: Severity Grading
  • Grade MR severity based on the quantified parameters, such as RVol and regurgitant fraction 3, 4, 5, 6
  • Consider the limitations and variability of MR severity grading using TTE and CMR 6