Safety and Outcomes of Intravenous Thrombolysis in Acute Ischemic Stroke with Intracranial Artery Dissection

<b>Background: </b> Intravenous thrombolysis (IVT) for acute ischemic stroke (AIS) related to underlying intracranial artery dissection (IAD) poses potential risks, including the exacerbation of intramural hematoma and the rupture of the dissected arterial wall. However, the safety of IVT in this specific population remains uncertain. <b>Aims:</b> This study aimed to assess whether IAD is associated with an increased risk of intracranial hemorrhage (ICH) following IVT and to evaluate its impact on functional outcomes. <b>Methods: </b> This retrospective matched-pair cohort study used a nationwide inpatient database that includes discharge abstracts and administrative claims data in Japan. We included adult patients with AIS treated with IVT between July 2010 and July 2024. We excluded patients with carotid or vertebral artery dissections due to difficulties distinguishing between intracranial and extracranial involvement, those lacking premorbid/discharge modified Rankin Scale (mRS) data, and those who received intra-arterial thrombolysis. Patients with IAD were matched 1:4 with non-IAD controls based on age, sex, premorbid mRS, endovascular treatment (EVT), and teaching hospital status. We assessed ICH, functional independence at discharge (mRS 0–2), and in-hospital mortality using multivariable logistic regression with generalized estimating equations to account for clustering within matched pairs, adjusting for age, sex, premorbid mRS, body mass index, smoking history, hypertension, diabetes mellitus, atrial fibrillation, coagulopathy, Japan Coma Scale, EVT, and teaching hospital status. <b>Results:</b> Of 83,139 patients with AIS treated with IVT, 242 (0.3%) had underlying IAD (median age 54 [46–67] years; 34% women). These patients were matched with 968 non-IAD controls. IAD was associated with a higher risk of ICH (odds ratio [OR], 3.18; 95% confidence interval [CI], 1.26–8.06) and a lower likelihood of functional independence at discharge (OR, 0.51; 95% CI, 0.37–0.72), but not with increased in-hospital mortality (OR, 1.09; 95% CI, 0.50–2.38). <b>Conclusions:</b> Patients with underlying IAD may face an increased risk of ICH and a reduced chance of functional recovery following IVT compared to those without.