Researchers at UC Irvine and Jefferson Health announced on Mar. 12 that their collaborative study has revealed important differences in how two main causes of mitral valve stenosis affect the heart. The findings could 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 when rheumatic disease was the most common cause of this condition. However, as rheumatic disease has become less common and cases caused by mitral annular calcification (MAC) have increased, researchers say these older standards may not be suitable for all patients.
“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 research team used advanced 3D ultrasound imaging and patient-specific lab models to compare how valves affected by immune damage differ from those stiffened by calcium buildup. They found that MAC-related stenosis can lead to smaller valve size and volume, unique changes in leaflet motion, and higher 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 need for more personalized approaches to diagnosing and treating mitral valve stenosis as populations age and cases become more complex. The research was partially supported by the National Institutes of Health (National Heart, Lung, and Blood Institute) and the National Science Foundation.
