The Cardiovascular
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HAT score (haemorrhage after thrombolysis)

Risk of symptomatic ICH after IV tPA in acute ischaemic stroke.

HAT score (haemorrhage after thrombolysis)
Baseline NIHSS
Serum glucose >200 mg/dL (>11.1 mmol/L) or history of diabetes
Hypodensity on baseline non-contrast CT
Result0 points

Risk of any intracerebral haemorrhage about 6 %; symptomatic haemorrhage about 2 %.

Any ICH
6 %
Symptomatic ICH
2 %

When to use

  • Estimating haemorrhagic risk before or after giving IV tissue plasminogen activator for acute ischaemic stroke.

Formula

Points: NIHSS <10=0, 10-20=1, >20=2; glucose >200 mg/dL or diabetes=1; CT hypodensity none=0, <=1/3 MCA=1, >1/3 MCA=2. Range 0-5.

Pearls and pitfalls

  • A higher score does not by itself contraindicate thrombolysis; it quantifies risk to inform shared decisions.

References

  1. Lou M, Safdar A, Selim M, et al. Neurology. 2008;71(18):1417-23.