The HAT Score: a simple grading scale for predicting hemorrhage after thrombolysis

Area of Science:

• Neurology
• Cardiovascular Medicine
• Medical Imaging

Background:

• Intracerebral hemorrhage (ICH) is a serious complication of ischemic stroke treatment with intravenous tissue-plasminogen activator (IV t-PA).
• Accurate prediction of ICH risk and prognosis is crucial for optimizing patient care and treatment decisions.

Purpose of the Study:

• To develop and validate a grading scale, the Hemorrhage After Thrombolysis (HAT) score, for predicting ICH risk and prognosis in patients receiving IV t-PA for ischemic stroke.
• To assess the scale's ability to stratify patients based on their likelihood of developing ICH and experiencing different functional outcomes.

Main Methods:

• A five-point HAT score was constructed using NIH Stroke Scale, CT hypodensity, baseline glucose, and diabetes history.
• The predictive performance of the HAT score was evaluated using c-statistics in two independent cohorts of patients treated with IV t-PA.

Main Results:

• The incidence of ICH increased with higher HAT scores, with symptomatic ICH rates ranging from 2% to 44%.
• The HAT score demonstrated good predictive ability for all hemorrhages (c-statistic 0.72), symptomatic hemorrhages (0.74), and fatal outcomes (0.79).
• The score also reasonably predicted good (mRS ≤ 2) and catastrophic (mRS ≥ 5) functional outcomes at 90 days.

Conclusions:

• The HAT score is a practical tool for risk stratification of ICH after IV t-PA in ischemic stroke patients.
• Further prospective validation in larger cohorts is needed to confirm the prognostic value and guide clinical decision-making regarding t-PA treatment benefits.