UC Irvine and Jefferson Health researchers announced on Mar. 12 that their collaborative study has revealed important differences in how two causes of mitral valve stenosis affect the heart. The findings may change how doctors diagnose and treat this condition, which restricts blood flow through the heart.
Mitral valve stenosis is a narrowing of the heart’s mitral valve, which can disrupt normal blood flow. Traditionally, doctors have used standards developed for rheumatic disease-related cases, but another cause—mitral annular calcification (MAC)—is becoming more common as the population ages. The new research shows that MAC-related stenosis behaves differently from rheumatic disease, suggesting that tailored diagnostic criteria are needed.
“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.”
The teams used advanced 3D ultrasound imaging and patient-specific laboratory models to compare how valves function under different conditions. They found that calcification leads to smaller valve size and volume, changes in leaflet motion, and increased pressure differences—even when the valve opening appears normal on imaging.
“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.”
The study highlights the importance of understanding these biological differences to improve diagnosis and treatment for patients with mitral valve narrowing—especially as heart valve disease becomes more common among older adults. The research was partially supported by the National Institutes of Health (National Heart, Lung, and Blood Institute) and the National Science Foundation.
