New programme helps gauge blood flow during flow diverter treatment of aneurysms

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A new computer programme allows interventionalists to assess blood flow in real-time while they are using flow-diverter devices to treat intracranial aneurysms, suggests a pilot study presented at the 27th annual International Symposium on Endovascular Therapy (ISET, 31 January–5 February, Hollywood, USA).

The researchers set out to study the effect of flow diverter implantation on blood flow in the vicinity of treated aneurysms, and aimed to develop a computer programme for real-time, quantitative assessment of blood flow during flow diverter implantation procedures.

Flow diverters are a class of endovascular devices for treating brain aneurysms by reconstructing the path of arterial flow and excluding an aneurysm from the circulation. “Increasing experience with flow diverters worldwide has shown that adverse flow changes due to the treatment may lead to severe complications in patients. Flow diverters typically are used to treat large (2– 2.5cm) or giant (more than 2.5cm) aneurysms, or those with wide necks,” the authors reported in the abstract.

“Until now, there was no safe way to measure the blood flow in real-time, during the procedure, including flow reduction to the aneurysm and flow to the rest of the brain,” said Aichi Chien, assistant professor of interventional neuroradiology, University of California, Los Angeles, USA. “Because the programme quantifies blood flow automatically, doctors do not need to stop the procedure to get this information, which helps them make the best decisions during the procedure.”

The Intracranial Stent Flow Mapping computer programme – IS FlowMap – takes advantage of the standard digital subtraction angiography (DSA) imaging being taken during the procedure. The program analyses the standard images, compares the difference in blood flow image to image and calculates the changes within seconds, providing that information to the interventionalist during treatment. If blood flow is not optimal, the doctor may choose to use a different treatment, such as placing coils in the aneurysm.

In the study, 13 patients were treated, and the average reduction in blood flow entering the aneurysm was 48%. The flow diverter healed the aneurysm in 11 (85%) of the patients.

“This pilot study quantitatively comparing the flow before and after flow diverter treatment showed that treatment leads to a significant and immediate reduction in flow entering an aneurysm,” the authors noted. 

“There are many advances in devices to treat patients with aneurysms and other vascular disease, but the technology to see the effects of those devices is very limited,” said Chien. “The IS FlowMap provides a simple way to analyse the treatment without any additional procedures or risk. We will be able to use this information moving forward to compare treatments and determine what amount of blood flow change is optimal.”