A new imaging technique used for measuring blood flow in the heart and vessels can diagnose a common congenital heart abnormality, bicuspid aortic valve, and could very well lead to better prediction of any future complications.
A Northwestern Medicine team reported their discoveries in the journal Circulation.
In the study, the researchers exhibited, for the first time a previously unknown relationship between heart valve abnormalities, blood flow changes in the heart, and aortic disease. They revealed that blood flow changes were caused by certain kinds of abnormal aortic valves, and they were able to directly link blood flow blueprints with aortic diseases.
"Blood flow in patients with bicuspid aortic valves was significantly different compared to that in patients with normal valves. We now have direct evidence that bicuspid valves induce changes in blood flow and that the type of flow abnormality may contribute to the development of different expressions of heart disease in these patients,” said senior author and associate professor of radiology at Northwestern University Feinberg School of Medicine, Michael Markl.
Bicuspid aortic valve is a heart condition in which the aortic valve only has two leaflets, instead of the usual three. It affects around one to two of every 100 Americans and is the most prevalent congenital cardiovascular abnormality. Regardless of the non-existence of symptoms, the condition can lead to major and potentially life-threatening complications, including enlargement of the blood vessel (aneurysm) and rupture. However, it is not known which patients are at the highest risk for complications and whether the condition's source is genetic or associated to changes in blood flow.
The 4D flow MRI (magnetic resonance imaging) employed during the course of the study has the potential for better predictive ability.
"The study demonstrated that new imaging techniques may help to determine patient-specific changes in blood flow to better understand which regional areas of the aorta are most prone to developing disease," said Markl.
"In addition, the knowledge of abnormal blood flow patterns could be important to better identify patients at risk for the development of heart disease."
Markl's team was quite taken aback when they saw such a clear distinction between individual expressions of aortic complications for different types of congenital valve disease. While the present data demonstrates evidence of this association, long-term observational studies are required to better understand the potential of 4D flow MRI to improve disease prediction ability.
A longitudinal follow-up study in patients with bicuspid aortic valves is currently being carried out at Northwestern.
"Ultimately, we hope that this imaging technique will facilitate early identification of high-risk blood flow patterns associated with progressive aortic enlargement, improving the allocation of health care resources in caring for patients with this prevalent condition," Markl concluded.