Heart blood flow modelling could be used by cardiologists to study blood flow in the atrium of patients with heart disease to assess stroke risk, according to researchers at Johns Hopkins Medicine.
The researchers used specialized CT (Computed Tomography) scans to create computer visualizations of the ‘shape’ of blood flow through the left atrium in the heart.
The team was able to show that in a healthy heart blood flows in a corkscrew pattern out of the left atrium into the left ventricle and onwards round the body. This flow pattern is the most efficient way of moving blood through the heart.
The tight vortexes help to move blood out of the heart more quickly, which means blood remains in contact with the surface tissue of the atrium for less time. The slower the blood moves, the greater potential there is for a clot to form. The researchers discovered that in a patient with heart disease the corkscrew motion did not occur.
Previous studies have shown that enlargement of the left atrium is linked to an increased risk of stroke, in particular in patients with atrial fibrillation; however, until this study was conducted, little was known about how blood flow through the heart was affected. The researchers were able to show through their modelling that in diseased hearts, instead of vortexes, the blood appears to flow out of the atrium “in sheets”.
“Our study fills in a missing diagnostic link between heart function and fluid motion in our understanding of how each can affect stroke risk,” said Hiroshi Ashikaga, Johns Hopkins assistant professor and Heart and Vascular Institute member. He also explained that heart blood flow modelling shows exactly how a ‘floppy’ heart can lead to the formation of blood clots and increase the risk of patients experiencing a stroke.
The study was only performed on two patients, a 68-year old man with an enlarged heart and a 58-year old woman with a healthy heart, both of whom underwent a CT scan for the study.
The research team has now expanded their study and are now monitoring blood flow on a much larger sample of patients over a longer term. The team will also be monitoring the incidence of stroke among those patients.
The study – A Computational Framework for Personalized Blood Flow Analysis in the Human Left Atrium – was published in November 2016 edition of the Annals of Biomedical Engineering.