Is intraprocedural intravenous aspirin safe for patients who require emergent extracranial stenting during mechanical thrombectomy?

BACKGROUND: Intraoperative antiplatelet therapy is recommended for emergent stenting during mechanical thrombectomy (MT). Most patients undergoing MT are also given thrombolysis. Antiplatelet agents are contraindicated within 24 hours of thrombolysis. We evaluated outcomes and complications of patients stented with and without intravenous aspirin during MT. METHODS: All patients who underwent emergent extracranial stenting during MT at the Royal Stoke University Hospital, UK between 2010 and 2020, were included. Patients were thrombolysed before MT, unless contraindicated. Aspirin 500 mg intravenously was given intraoperatively at the discretion of the operator. Symptomatic intracranial haemorrhage (sICH) and the National Institutes for Health Stroke Scale score (NIHSS) were recorded at 7 days, and mortality and functional recovery (modified Rankin Scale: mRS ≤2) at 90 days. RESULTS: Out of 565 patients treated by MT 102 patients (median age 67 IQR 57-72 years, baseline median NIHSS 18 IQR 13-23, 76 (75%) thrombolysed) had a stent placed. Of these 49 (48%) were given aspirin and 53 (52%) were not. Patients treated with aspirin had greater NIHSS improvement (median 8 IQR 1-16 vs median 3 IQR -9-8 points, p=0.003), but there were no significant differences in sICH (2/49 (4%) vs 9/53 (17%)), mRS ≤2 (25/49 (51%) vs 19/53 (36%)) and mortality (10/49 (20%) vs 12/53 (23%)) with and without aspirin. NIHSS improvement (median 12 IQR 4-18 vs median 7 IQR -7-10, p=0.01) was greater, and mortality was lower (4/33 (12%) vs 6/15 (40%), p=0.05) when aspirin was combined with thrombolysis, than for aspirin alone, with no increase in bleeding. CONCLUSION: Our findings based on registry data derived from routine clinical care suggest that intraprocedural intravenous aspirin in patients undergoing emergent stenting during MT does not increase sICH and is associated with good clinical outcomes, even when combined with intravenous thrombolysis.