Capillary blush (or angiographic blush), arteriovenous shunting and early venous filling are terms variably used in digital subtraction cerebral angiography following reperfusion of thromboembolic ischemic stroke to denote the appearance of the reperfused tissue. They are related to each other and represent the abnormal response of affected tissue to a period of ischemia followed by reperfusion. Generally, they have been associated with worse outcomes, however, this depends somewhat on the exact definitions used 1-5.
Capillary blush
A capillary blush, also sometimes referred to as an angiographic blush, is seen immediately following successful recanalization of a large vessel occlusion (e.g. with endovascular clot retrieval) and refers to abnormally early and intense contrast enhancement of the affected tissue 4. This is often associated with early passage of contrast through the capillary bed and into the draining veins, in turn resulting in early venous filling (see below).
A capillary blush is a poor prognostic sign and indicates that the affected tissue has, or will go onto, ischemic infarction despite reperfusion 4.
It is important to distinguish this abnormally intense and persistent capillary blush from the normal capillary phase of angiograms. One area of potential confusion is distinguishing capillary blush from the capillary index score (CIS) used in a number of stroke trials which refers to a "capillary blush" on pretreatment angiograms to denote normal, or at least better-perfused, brain which in turn has a good prognosis 6-8.
Early venous filling
Early venous filling denotes early contrast opacification of the cerebral vein draining the affected tissue before the late arterial phase 2. It results from a failure of autoregulation of the microcirculation and results in excessive blood flow relative to metabolic requirements (which are actually reduced as the tissue is infarcted) through vasodilated capillaries, such that contrast passes through the capillary bed and into the venous circulation faster than normal 3. This can be thought of as the angiographic equivalent of luxury perfusion 3.
Early venous filling is, therefore, a surrogate marker of substantial ischemic damage and usually occurs in tissue that has, or will go on to, ischemic infarction 2,3. It has also been shown to increase the risk of post-reperfusion hemorrhagic transformation substantially 2-5.
Unable to process the form. Check for errors and try again.