Non Invasive CardiologyQuality Assurance Summit “3rd Quarter 2010”
Summit Agenda• Evaluation of Mitral Regurgitation: “American Society of Echocardiography Guidelines”• Quality Assurance Case Review• Interesting Case Study Review• “Technical Tips for Today’s Sonographers”• Open Discussion for Miscellaneous Topics• Adjournment
Recommendations for the Evaluation of the Severity of: “Native Valvular Regurgitation” With 2D Echocardiography and Doppler Mapping
Role of 2D Echocardiography and Doppler Mapping• Evaluation of Valvular Structure• Impact of Volume Overload on Chambers• Cardiac Remolding: Not Specific for the degree of Regurgitation• With significant Regurgitation perform serial 2D Echocardiograms with Doppler Mapping as the method of choice for Follow Up Evaluations• Idea of these Evaluations is the timing of Surgery (Critical)“Transesophageal Echocardiography may be used when Clinically necessary…….”
Doppler Method for the Evaluation of Regurgitation Modalities:• Color Doppler• Pulse Wave• Continuous Wave
Color Doppler Evaluation• Origin of the Regurgitant Jet• Width: Vena Contracta• Spatial Orientation of Regurgitant Jet Orifice• Flow convergence into the Regurgitant Orifice• Better than assessing the traditional Jet Area alone…….
Color Doppler EvaluationSize of Regurgitant Jet Area of Regurgitant Jet• Color Flow Mapping • Rapid Screening:• Temporal Resolution Eccentric Jets• Instrument Settings • Semi Quantitative (Gain, Output) Impinging Jets• Nyquist Limit • Underestimated Jets• Sample Volume Size • Sole Reliance: Misleading• Depth of the Sector
Technical Aspects• Pulse Repetition Frequency: The jet area is inversely related to the PRF……• Color Gain: Eliminate random Color Speckling from non – moving regions• Aliasing Velocity: 50 to 60 cm/second• Importance of measuring the Patient’s Blood Pressure: Contributes to the driving force across the Valves……
Vena Contracta• Narrowest portion of • Measure Cross the Jet at or just Sectional Area (EROA) downstream from the • Affected by changing Orifice Hemodynamics and• High Velocity Cardiac Cycles• Laminar Flow • Considerably less• Slightly smaller than sensitive to technical the anatomical factors such as PRF Regurgitant Orifice
Technical Aspects• It is often necessary to • Narrow the Color Flow angulate the Doppler Sector Transducer out of • Use the least Depth to normal Echo Planes maximize Lateral and• Optimize: Downstream Temporal Spatial expansion is Resolution distinguished……. • Small Errors in• Preferable Zoom Mode Measurements, larger Percentile Errors……
PROXIMAL ISOVELOCITY SURFACE AREA “PISA or Flow Convergence”
Hemodynamic PrincipleAs Regurgitant Flow approaches:• Increased Velocity• Concentric Hemispheric Shell• Decreased Surface Area• EROA = (6.28 r² x Aliasing Velocity) MR Velocity• MR Velocity is obtained with CW and measuring the Peak Velocity• EROA Measurement is slightly larger than other Method……..
Technical Aspects• Shift Baseline towards direction of Flow• Decrease Nyquist Limit• This technique is more accurate for Central Jets………
Pulse Wave Doppler Flow Method• Stroke Volume: Product of the Cross Sectional Area (CSA) and Velocity Time Interval (VTI)• Regurgitant Volume: SV of the Regurgitant Valve, SV of the Competent Valve• Regurgitant Fraction = SV Regurgitant Valve – SV Competent Valve Stoke Volume – Regurgitation• EROA = Regurgitant Volume VTI Regurgitant Jet
Technical Aspects• Proper Annular Measurement• Use the Velocity Trace Method, to calculate both a Maximum and Mean Velocity…….• Select the most “defined and brightest” Spectral Doppler Waveform• Position the Sample Volume with minimal angulation at the level of the Annulus