A closer look at heart health

Your heart depends on careful coordination of its components, and even small disruptions can affect the whole system. One condition that troubles many people across the country is mitral valve stenosis - a narrowing of the valve that can restrict blood flow through the heart.

Two research teams - one at UC Irvine and one at Philadelphia-based Jefferson Health - have been collaborating to explore this condition in detail, and what they've discovered has important implications for how doctors understand and treat it. Their study helps explain why two causes of valve narrowing - one from immune damage and another from calcium buildup - affect the heart in very different ways.

Not all narrowing is the same

When doctors evaluate mitral valve stenosis, they usually rely on standards that were developed when the condition was overwhelmingly due to rheumatic disease. Rheumatic heart disease happens when untreated streptococcal infections damage the heart valves, especially the mitral valve. Over the last few decades, though, rheumatic disease has become uncommon, while another cause, mitral annular calcification, is increasingly encountered. The current research reveals that mitral valve stenosis due to MAC affects blood flow through the heart differently than does rheumatic disease and may be better understood with tailored criteria.

"For decades, mitral stenosis has been assessed using a one-size-fits-all approach," said senior co-author Dr. Arash Kheradvar, UC Irvine professor of radiological sciences, biomedical engineering and medicine. "But MAC-related stenosis behaves differently. The valve structure is different and blood flow patterns are different, and the relationship between anatomy and severity doesn't follow the same rules as seen in rheumatic disease."

Using cutting-edge 3D ultrasound imaging and patient-specific lab models, the team compared how valve structures and blood flows behave under different conditions. The researchers found that when calcification stiffens the valve:

• Valve size and volume may be smaller.
• Leaflet motion and structure shift in ways different from rheumatic valves. (Leaflets are flexible tissue flaps in heart valves that ensure blood flows in one direction without backflow.)
• Pressure differences and energy losses in the heart rise even when the valve opening looks relatively "normal."

"What's striking is that patients with MAC-related stenosis can appear to have a reasonably sized opening on imaging yet experience pressure gradients and energy losses that mimic much more severe obstruction," said senior co-author Dr. Gregg Pressman, Jefferson Health professor of medicine. "That mismatch between anatomy and hemodynamics helps explain why conventional thresholds can fail in this population."

What this means

Mitral valve narrowing affects people of all ages but particularly the elderly and those with poor kidney function. As our population grows older and lives longer, heart valve disease is becoming more common - and understanding its nuances is increasingly important.

By uncovering the biological differences behind these two causes of mitral valve stenosis, the collaborating UC Irvine and Jefferson Health teams are helping doctors move beyond a one-size-fits-all framework and toward more precise, individualized care. The findings could lead to improved interpretation of diagnostic tests and better-informed treatment decisions, with the potential to improve quality of life and long-term outcomes for patients and families alike.

Why this matters

• Closer to personalized care: Understanding how different causes of mitral valve stenosis behave can help doctors tailor diagnosis and treatment to an individual patient's needs.
• Brighter heart-health outlooks: The research underscores the need for better ways of finding and treating severe cases that traditional methods may fail to catch.
• Better patient outcomes: Improved methods of assessing the condition can lead to safer and more effective care in the long run.

This research was partially supported by the National Institutes of Health (National Heart, Lung, and Blood Institute) and the National Science Foundation.