A common question in structural heart cardiology is “when do we know to intervene?” and recently released 25-year mitral regurgitation data might just have given us an answer.
- While we have access to structural metrics like regurgitant orifice area (ERO) for when to intervene, long-term prognosis and optimal MR treatment timing remain elusive.
- ERO is a way of measuring the size of the opening or “hole” left by a heart valve when it fails to close all the way, which is what allows blood to leak backward.
Using ERO as a North Star, researchers followed 449 asymptomatic degenerative MR patients for a median of 26 years, and used the metric to determine the severity of their MR progression, as well as when to move from medical therapy to surgery.
- As patients’ ERO got larger, medical therapy survival rates decreased.
- For example, the 5-year survival rate for the smallest ERO category was 88% versus 55% for the largest.
- During the follow-up, 57% of patients underwent mitral valve surgery.
When extending the follow-up to include post-surgery outcomes, the survival gap between operated and non-operated patients also widened as ERO increased.
- Critically, that divergence began at ERO values above 30 mm².
That’s below the current guideline directed threshold for severe MR (40 mm²), putting the benefit squarely in the upper-moderate range.
- Of course, there’s far more to defining when to intervene in MR than ERO.
- Rather, this cutoff discovery is most useful when combined with other echo parameters, and the broader heart’s response to therapy.
Zooming out a bit also gives us insight into a consistent structural heart trend, which is that earlier intervention is better than watchful waiting or medical therapy.
- That’s because past a certain point, the structural damage from a leaky mitral or aortic valve is irreversible.
The Takeaway
With the pace of modern cardiology, it’s pretty rare to get 25-year data for anything, and this study tells us that ERO serves as a mathematical cutoff for understanding how much the outcomes of MR surgery will be impacted by waiting too long.
