Despite the fact that PAI‐1 is the most effective natural inhibitor of t‐PA, to date, its role in the outcome of ischemic stroke thrombolytic therapy has not been fully elucidated.27 A major finding of this study is that PAI‐1 5G/5G genotype confers an independent, significant risk for post‐lysis ICH. The gene discussed is SERPINE1; the disease is ischemic stroke.