Genetically proxied prothrombin levels were significantly associated with increased risk of ischemic stroke (OR, 1.36 [95% CI, 1.17–1.57]; P=5.0×10−5) and CES (OR, 1.83 [95% CI, 1.31–2.57]; P=4.2×10−4) and were nominally associated with the risk of LAAS (OR, 1.63 [95% CI, 1.04–2.57]; P=0.03). Here, F2 is linked to ischemic stroke.