People with severe aortic valve narrowing (aortic stenosis) suffer from chest pain and breathlessness, even though their coronary arteries are of normal size. Now a new paper published in JACC Cardiovascular Imaging has clarified the underlying mechanism for the reduced heart muscle blood supply which causes these symptoms.
The study, led by Dr Masliza Mahmod and Professor Stefan Neubauer, used donated tissues samples from 14 patients who were undergoing an aortic valve replacement to treat their severe aortic stenosis. Even though the aortic valve narrowing in these patients was serious enough to warrant heart surgery, the width of their coronary arteries, as they are visible on angiograms, was normal, (which meant that their symptoms were not caused by coronary artery narrowing.)
Before patients underwent surgery, the researchers also measured blood flow through the heart muscle in these patients, using the cutting-edge technology at OCMR.
The researchers found that compared to tissue samples from people with no heart disease, patients with severe aortic stenosis had fewer small arteries (which are too small to see on angiograms) in their heart muscle. What’s more, there was damage to the inner lining of the small arteries that were there.
This damage was the worst in patients with the most severe aortic valve narrowing, and it correlated with poorer heart muscle blood flow as well. This heart muscle blood flow also got better after surgery, as measured in the patients who came back six months after their surgery.
Our study provides evidence that detection of reduced blood supply by cardiac magnetic resonance scan could be used to select people who would benefit from aortic valve replacement, instead of relying on presence of symptoms which can be unreliable
- Dr Masliza Mahmod, OCMR Head of Clinical Trials and study first author
The results of this study suggests that reduced blood supply to the heart muscle of patients with severe aortic stenosis could be caused by damage to the inner lining of the small arteries of the heart muscle, and that this damage might be reversible.
Professor Stefan Neubauer, the senior author of the paper said, “Treatment to protect inner lining of small blood vessels of the heart muscle is a promising treatment target. This has the potential to delay onset of symptoms and timing of surgery. Future research in this area is therefore needed.”
Read the full paper.