Severe MS can be defined by which combination?

Severe MS can be defined by which combination?

• A. Mild MS is defined by mean gradient >5 mmHg.
• B. Moderate MS is defined by PHT less than 150 ms.
• C. Severe MS can be defined by PHT ≥ 220 ms or mean gradient > 10 mmHg.
• D. PHT alone defines MS severity; mean gradient is not used.

Answer: (C)

Severe mitral stenosis is judged by how much the valve narrows the flow, which Doppler evaluates with two measurements: the pressure half-time (PHT) and the mean transmitral gradient. A longer PHT means slower filling across the narrowed valve, reflecting a smaller valve area, while a higher mean gradient shows greater resistance to flow. Clinically, severe MS is defined by either a PHT of 220 ms or greater, or a mean gradient of more than 10 mmHg. This approach recognizes that either criterion reaching a severe threshold indicates significant obstruction. The other statements aren’t correct because mild MS would not have a mean gradient above 5 mmHg, moderate MS is not defined by a PHT less than 150 ms, and severity isn’t determined by PHT alone—you also use the mean gradient to assess severity.

Severe mitral stenosis is judged by how much the valve narrows the flow, which Doppler evaluates with two measurements: the pressure half-time (PHT) and the mean transmitral gradient. A longer PHT means slower filling across the narrowed valve, reflecting a smaller valve area, while a higher mean gradient shows greater resistance to flow. Clinically, severe MS is defined by either a PHT of 220 ms or greater, or a mean gradient of more than 10 mmHg. This approach recognizes that either criterion reaching a severe threshold indicates significant obstruction. The other statements aren’t correct because mild MS would not have a mean gradient above 5 mmHg, moderate MS is not defined by a PHT less than 150 ms, and severity isn’t determined by PHT alone—you also use the mean gradient to assess severity.