Optical Coherence Tomography Angiography (OCTA) to Assess Cardiac Output and Cerebral Perfusion at the Time of Children's Cardiac Surgery

Around 3500 children including 1,000 babies a year in the UK require heart surgery. Open-heart repairs involve the heart being stopped, while blood is pumped around the body using a cardiopulmonary bypass machine. Following complex operations, the patient may temporarily develop poor heart function, leading to reduced organ blood supply. Low heart output leads to post-operative complications or even death. The current methods to assess cardiac output and to see if vital organs, especially the brain, are receiving enough blood flow, are indirect and can be inaccurate. If we find a better way to detect and then avert or ameliorate periods of poor cardiac output and / or reduced brain perfusion, then this would be helpful for clinicians and could lead to better outcomes for children.

We believe that optical coherence tomography angiography (OCTA), a non-invasive way to image the blood vessels in the retina at the back of the eye, could help us to assess cardiac output and brain perfusion. The OCTA machine was approved for use in humans in 2019 and given a CE Marking, but it has previously been used mainly in the management of eye diseases. There is a small amount of experience with its use in critically ill adults. We plan a pilot study to see if it is possible to use the OCTA machine at key time points, before, during and after children's heart operations, in 30 patients. We will study the images taken with OCTA machine to see if they are of good quality and we will analyze the images to see whether or not the expected changes in cardiac output and brain perfusion that occur with heart surgery can be detected as changes in blood flow in the back of the eye. Depending on the success of this pilot, we will plan further studies.