Average remission ADAMTS13 activity in patients without stroke (n = 43) and with stroke (n = 8). Median average remission ADAMTS13 activity was lower in patients with stroke vs those who did not develop stroke during follow-up (33% [IQR, 20%, 49%] vs 71% [IQR, 33%, 96%]; P = .021). The dashed line represents ADAMTS13 activity of 70%, where an arbitrary threshold of >70% is considered normal.