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Valve Regurgitation. Echocardiographic Calculations Rami Khouzam, MD. Definitions/Equations:. Continuity equation: Flow (SV) = LVEDV - LVESV = A x TVI (SV:Stroke Volume, A: Area, TVI:Time Velocity Integral) Flow 1(SV) = Flow 2 (SV) A1 x TVI 1 = A2 x TVI2.
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Valve Regurgitation Echocardiographic Calculations Rami Khouzam, MD
Definitions/Equations: • Continuity equation: • Flow (SV) = LVEDV - LVESV • = A x TVI • (SV:Stroke Volume, A: Area, TVI:Time Velocity Integral) • Flow 1(SV) = Flow 2 (SV) • A1 x TVI 1 = A2 x TVI2
TVI • Time Velocity Integral = stroke distance (cm). • The distance over which blood travels in one cardiac cycle: the cycle velocity (cm/s) divided by time (s). Usually represents Mean gradient. • Different than V (Velocity): m/s or cm/s. • Usually represents Peak Instantaneous gradient.
Area • Area = r2 • = 3.14 r2 (radius) • = 0.785 d2 (diameter)
Flow 1(SV) = Flow 2 (SV) • A1 x TVI 1= A2 x TVI2 • Inflow = Outflow • A(MV)x TVI(MV)= A(LVOT)x TVI(LVOT)
Regurgitant Volume • Regurgitant Volume (mL) = • SV (Valve) - SV (systemic) • Regurgitant Fraction • Regurgitant Fraction (%) = • SV (Valve) - SV (systemic) / SV (Valve)
Examples • Mitral Regurgitation • d(MV) = 3.5 cmd(LVOT) = 2.0 cm • TVI (MV) = 10 cmTVI (LVOT) = 20 cm • Calculate the Regurgitant Volume? • A(MV)x TVI(MV)- A(LVOT)x TVI(LVOT) • = 96 - 62 • = 34 mL
Aortic Regurgitation • d(MV) = 3.5 cmd(LVOT) = 2.5 cm • TVI (MV) = 8 cmTVI (LVOT) = 25 cm • Calculate the Regurgitant Volume? • A(LVOT)x TVI(LVOT) - A(MV)x TVI(MV) • = 122 - 76 • = 46 mL
ERO • Effective Regurgitant Orifice area (cm2) = • Regurgitant Volume (mL) / TVI MR (cm) • Effective Regurgitant Orifice area (cm2) = • Flow (mL/s) / V MR (cm/s)
Example • Mitral Regurgitation • d(MV) = 3.5 cmd(LVOT) = 2.0 cm • TVI (MV) = 10 cmTVI (LVOT) = 20 cm • TVI (MR) = 120 cm • ERO (cm2) = RV (mL) / TVI MR (cm) • = 34/120 • = 0.28 cm2 • =28 mm2
Aortic Regurgitation • d(MV) = 3.5 cmd(LVOT) = 2.5 cm • TVI (MV) = 8 cmTVI (LVOT) = 25 cm • TVI (AR) = 188 cm • ERO (cm2) = RV (mL) / TVI AR (cm) • = 46/188 • = 0.38 cm2 • = 38 mm2
Tips • Inflow > Outflow : MR • Inflow < Outflow : AR
More Examples • A 65 yo M with NYHA class II symptoms. EF 55 %. • d MV = 4 cm d LVOT = 2 cm • TVI MV = 10 cm TVI LVOT = 20 cm • V Ao = 1.2 m/s • What’s next? • a) Operate for MR • b) Operate for AR • c) Observe MR • d) Observe combined AS/AR
Regurgitant Volume? • A(MV)x TVI(MV)- A(LVOT)x TVI(LVOT) • = 125.6 > 62.8 • = 62 mL • Inflow > Outflow: MR • Answer: a
A patient has: • d MV = 4 cm d LVOT = 2.5 cm • TVI MV = 4 cm TVI LVOT = 25 cm • V Ao = 2.5 • This patient should have: • a) Absent A2 • b) Opening snap • c) Quincke’s pulse • d) Large V-wave • e) Clubbing
A(MV)x TVI(MV)- A(LVOT)x TVI(LVOT) • = 50.2 < 122.6 • = 72 mL • Inflow < Outflow: AR • Answer: c