Schematics of the millisecond-scale SIPA process driving the arterial thrombus growth under pathologically high shear rates. (A) Under pathological high shear (∼10 000 s⁻¹), VWF elongates under high shear due to the elongational effect of shear flow. (B) Elongated soluble VWFs entangle many nonactivated platelets and form agglomerates in the flow, facilitated by the rotational flow. (C) The immobilized VWF at the wall captures agglomerates in milliseconds after an agglomerate traveling lag distance of >100 $μ$m. (D) Summary of the steps and features of SIPA described in current study.