Background: Intravenous thrombolysis is a high risk first line reperfusion therapy for acute ischaemic stroke. Recommended weight-based doses have been carefully selected to balance recanalization rates against the risk of intracranial haemorrhage. The literature suggests variable accuracy in the weight used to calculate thrombolysis dose, but Australian studies are lacking.
Aims: To evaluate weight acquisition methods for thrombolysis, compare the reported weight to in-hospital measurements, and assess whether weight overestimation correlates with haemorrhagic transformation.
Methods: Consecutive patients who received intravenous thrombolysis from January 2019 to June 2022 were identified from Box Hill Hospital’s stroke database. Variables including weight used, pre and post thrombolysis blood pressure were extracted from electronic records. A paired t-test was used to compare weight used acutely with measured weight. Multivariable regression was used to explore weight discrepancy associations with CT-proven intracranial haemorrhage at 24 hours. Patients who were transferred for endovascular clot retrieval were excluded from the haemorrhagic transformation analysis.
Results: Of 354 patients (median age 77, IQR 66-84; 54.8% male), patient or family-reported weight was used for thrombolysis dosing in 34 cases, and stroke team estimates in 153 cases. In 174 cases it was unknown if the weight was reported or estimated. Measured weight was missing in 92 patients. Although there was no statistical difference between weight used acutely and measured weight (N = 262, p=0.38), 74 patients had discrepancies over +/-5kg. No association was found between weight overestimation or blood pressure with haemorrhagic transformation (N = 44, missing radiology data = 21).
Conclusion: Documentation of patient’s weight can be improved, including methods of weight acquisition for thrombolysis dosing and post-admission measurements. Withstanding these limitations, 72% of patients were thrombolysed with weight within 5kg of their measured weight.