Statins Do Not Slow Growth of Intracranial Aneurysms
Based on the highest quality evidence, statins should not be used to prevent growth or rupture of unruptured intracranial aneurysms, as observational findings do not support their use for prevention. 1
Guideline Recommendations
The 2015 AHA/ASA Guidelines for Management of Unruptured Intracranial Aneurysms explicitly state that while statins may theoretically retard aneurysm formation through inhibition of nuclear factor-κB and other pathways, observational findings are not supportive of the use of statins for prevention. 1 This represents the most authoritative guidance on this specific question and directly addresses intracranial aneurysms.
Supporting Clinical Trial Evidence
The most recent randomized controlled trial data reinforces the guideline position:
The SAVE Study (2021) was the first multicenter randomized controlled trial specifically designed to test whether atorvastatin prevents growth of small unruptured intracranial aneurysms. 2 This study enrolled 231 patients with 275 target aneurysms and found no significant beneficial effects of statin therapy for the primary endpoint of aneurysm growth ≥0.5 mm, new bleb formation, or rupture (log-rank P = 0.359). 2
The trial compared 107 aneurysms in the statin group versus 140 aneurysms in the control group, with no aneurysm ruptures occurring in either group during follow-up. 2
Observational Data Shows No Protective Effect
A large Medicare database study of 28,931 patients with unruptured cerebral aneurysms (mean follow-up 30 months) found that current or recent statin use was not associated with any difference in subarachnoid hemorrhage risk (OR 1.03,95% CI 0.86-1.23). 3 Similarly, no association was found between statin use and the composite outcome of subarachnoid hemorrhage or aneurysm treatment (OR 0.94,95% CI 0.84-1.06). 3
Context: Distinction from Other Vascular Conditions
It is important to distinguish intracranial aneurysms from thoracic aortic aneurysms, where some evidence suggests potential benefit:
For thoracic aortic aneurysms, the 2022 ACC/AHA guidelines note that animal studies have shown reduction in thoracic aneurysm growth with statin therapy, possibly via regulation of MMP activity, and some observational human studies suggest slowing of aortic growth. 1
However, even for thoracic aortic disease, the 2010 ACC/AHA guidelines explicitly stated there are no clinical outcomes data that justify statin use to prevent expansion after thoracic aortic aneurysms have developed. 1
Clinical Implications
Do not prescribe statins with the expectation of preventing intracranial aneurysm growth or rupture. 1 If a patient with an unruptured intracranial aneurysm has other indications for statin therapy (such as atherosclerotic cardiovascular disease, diabetes, or elevated LDL cholesterol), statins should be prescribed for those standard indications—but not for aneurysm stabilization. 1
The focus for unruptured intracranial aneurysms should remain on established risk factor modification: smoking cessation, hypertension control, and appropriate surveillance imaging based on aneurysm size and location. 1