Findings in animal studies, which are currently being tested for confirmation in humans, have found that naturally occurring variants of a novel "collateral gene", [[Rabep2]], result in large differences in the extent of anatomic collaterals and thus blood flow and infarct size in [[mice]] after [[stroke]]. The comprehension of [[collagerogenesis]] in humans and the evaluation of collateral status could aid in identifying patients who will benefit not only from [[mechanical thrombectomy]] in the extended time window, but also from any [[reperfusion]] strategy. 

Piedade et al. performed a literature review focused on radiographic, clinical and genetic aspects of the collateral circulation
((Piedade GS, Schirmer CM, Goren O, Zhang H, Aghajanian A, Faber JE,
Griessenauer CJ. Cerebral collateral circulation: A review in the context of
ischemic stroke and mechanical thrombectomy. World Neurosurg. 2018 Oct 17. pii:
S1878-8750(18)32363-5. doi: 10.1016/j.wneu.2018.10.066. [Epub ahead of print]
Review. PubMed PMID: 30342266.
)).