- Christoforidis G, Karakasis C, Mohammad Y, Caragine L, Yang M, Slivka A. Predictors of hemorrhage following intra-arterial thrombolysis for acute ischemic stroke: the role of pial collateral formation. AJNR Am J Neuroradiol. 2009;30:165-70 pubmed publisher..1) and platelets <200,000/microL (OR = 8.1) were statistically significant predictors of significant hemorrhage. Poor pial collateral formation is associated with higher incidence and larger size of hemorrhage following IAT. ..