Effect of Statin on Radiographic and Clinical Outcomes of Intracranial Aneurysms Treated Through Pipeline Embolization Device – a Propensity Score Matched Analysis

Introduction: Studies have shown that the use of statin can improve radiographic and clinical outcomes in patients receiving endovascular treatment for coronary artery or peripheral vascular stenosis. Statins are thought to be effective by reducing arterial wall inflammation. The same mechanism may have an influence on the efficacy of pipeline embolization device (PED). While this question has been of interest, there is lack of well controlled data in the literature.

Methods: Patients who underwent PED for unruptured intracranial aneurysms were identified. Patients on statin treatment versus those who were not were matched through propensity score by controlling for confounding factors including age, gender, diabetes, aneurysm morphology, volume, neck size, location of aneurysm, history of treatment for the same aneurysm, and elapsed time at last follow up. Occlusion status, incidence of in-stent stenosis and ischemic complications during the follow-up period were extracted for comparison.

Results: Among the included patients, 146 were on statin therapy, 346 were not. After one-to-one nearest neighbor matching, 57 cases in each group were compared for outcomes. At first follow up, 73.7% and 70.2% had complete obliteration in statin and non-statin groups respectively (p=0.76). At last follow-up, 45 cases (79%) in each group had complete occlusion (p=1). In-stent stenosis trended higher in the statin group compared to the non-statin group (17.5% vs 5.3%, p=0.074). However, it was not correlated with statin intensity (p=0.83). Despite having a difference of in-stent stenosis, no significant difference was found in the incidence of ischemic complications between the two groups (p=1).

Conclusion : Statin use does not affect occlusion rate or clinical outcomes in patients treated with PED treatment for unruptured intracranial aneurysms. However, the incidence of in-stent stenosis was actually higher in patients on statins. This may relate to baseline hyperlipidemia and more rigorous management of hyperlipidemia should be considered in this group of patients.