Zurich – A team from the University of Zurich (UZH) has discovered that the risk of cerebral hemorrhage increases after a stroke if the brain is supplied with blood again too quickly after the blood clot has been removed. This happens when vascular bridges between neighboring arterial trees are blocked.
The success of treatment after a stroke depends on the so-called collateral network. This has now been discovered and published by a research group at UZH.
Collaterals are blood vessels that connect neighboring arterial trees. They can act as a bypass in the event of a narrowing or blockage of arteries that supply the brain with blood. This is particularly important after the medical or surgical removal of a blood clot in the brain. This is because "these vascular bridges maintain the self-regulation of the brain and enable a slower, gradual reperfusion, which leads to smaller infarcts," group leader Susanne Wegener is quoted as saying in a UZH report. She is a professor at UZH and a senior physician at the Department of Neurology at the University Hospital Zurich.
In experimental animals that had poor collaterals, the researchers saw that the arterial segments were dysfunctional and rigid after removal of the clot. "The subsequent excessive reperfusion led to bleeding and increased mortality in the mice," says Wegener.
The team was then able to confirm the results from the mouse model in stroke patients. A similarly rapid and excessive reperfusion of the brain area caused small hemorrhages in them and their recovery was worse.
So the conclusion is: the better the arterial connections, the better the recovery. According to Wegener, future therapeutic measures should therefore aim to "improve the function of the vascular bridges in order to enable a favorable, gradual reperfusion after the stroke". ce/mm