Which Doppler technique correlates best with cath lab findings for mean pressure gradient?

• A. Continuous Wave Doppler Mean PG
• B. Pulsed Wave Doppler Mean PG
• C. Color Doppler Velocity
• D. Tissue Doppler

Answer: (A)

Capturing the full velocity waveform across the valve during systole is essential to estimate the mean pressure gradient noninvasively. The mean gradient is derived from how the pressure difference changes throughout the flow pulse, not just from a single velocity value. Continuous-wave Doppler provides a continuous velocity signal along the entire line of sight, so you get the complete velocity-time curve even with very high jets. This allows accurate calculation of the mean gradient, which tends to align well with what is measured invasively in the cath lab.

Pulsed-wave Doppler samples a specific depth and has a finite range and Nyquist limit, so it can miss peak velocities or underestimate the jet in severe stenosis, making the mean gradient less reliable. Color Doppler shows flow direction and presence but doesn’t provide the velocity data needed to compute gradients. Tissue Doppler measures myocardial tissue movement, not the blood flow across the valve, so it isn’t used for gradient estimation.