Severe MS Without a Gradient: How the Tool Classifies It
MVA 1.2 cm² by planimetry in sinus rhythm, no mean gradient obtained. Does absent gradient downgrade reliable severe-range MVA?
Clinical scenario
MVA 1.2 cm² by 2D planimetry. Sinus rhythm. No mean gradient obtained (study terminated due to patient discomfort). How is this classified?
The patient is a 62-year-old woman with exertional dyspnea. Echo performed as part of pre-surgical workup. Planimetry shows MVA 1.2 cm². Gradient not obtained. No AF. No documented low-flow state. No PHT pitfalls applicable (planimetry used).
Tool output
severe_ms_pattern
MVA 1.2 cm² by planimetry (high confidence) is in the severe range (≥ 1.0, ≤ 1.5 cm²). No gradient confounders. Absent gradient = context absent, not a conflicting signal. Grade: severe_ms_pattern.
Why absent gradient does not downgrade
The tool grades MS severity on MVA. Mean gradient provides hemodynamic context — it is not a co-equal grading criterion. When gradient data is absent, the tool does not introduce uncertainty about the MVA. With a high-confidence planimetry measurement in the severe range and no confounders, the grade is severe_ms_pattern.
This is a deliberate design principle: absent gradient ≠ downgrade. The only way gradient absence shifts the grade is if MVA is in the moderate range and a high gradient would be needed to establish hemodynamic significance — but even then, the tool would grade on MVA first.
What happens if gradient was obtained?
If mean gradient ≥ 10 mmHg were documented, the tool would add a concordant hemodynamic finding flag. If gradient < 10 mmHg were documented, a low_gradient_context caution would be added — but the grade would remain severe_ms_pattern (not discordant, because MVA is 1.2 cm², not < 1.0 cm²). Discordant classification requires MVA < 1.0 cm².
Teaching points
- Absent gradient does not downgrade reliable severe-range MVA. The tool grades on MVA first.
- Gradient absence is captured as 'gradient_absent_or_unavailable' — a context flag, not a penalizing signal.
- Discordant MS hemodynamics (discordant_ms_hemodynamics) requires MVA in the very severe sub-range (< 1.0 cm²) — MVA 1.2 cm² is in the severe range and is not subject to the discordant check.
- High-confidence MVA methods (planimetry, 3DE, IVPG) are not subject to PHT pitfall downgrade — method confidence is high regardless of gradient.
Apply this in practice
Reproduce this case in the MS Severity Tool and observe how method confidence and gradient absence interact.
Try it in the tool