Can antihypertensive medication, such as Angiotensin-Converting Enzyme (ACE) inhibitors or Angiotensin II Receptor Blockers (ARBs), prevent the formation of a brain aneurysm?

Blood Pressure Medication and Brain Aneurysm Prevention

Treatment of hypertension with antihypertensive medication is recommended to prevent ischemic stroke, intracerebral hemorrhage, and other end-organ injury, but the relationship between blood pressure control and prevention of brain aneurysm formation remains uncertain. 1

Evidence for Hypertension as a Risk Factor

Hypertension is strongly associated with intracranial aneurysm development and rupture, though the exact mechanisms remain incompletely understood:

• Hypertension increases aneurysm rupture risk significantly, with odds ratios of 2.559 for hypertensive versus non-hypertensive patients 2
• The mean incidence of pre-existing hypertension in aneurysm patients is 43.5% compared to 24.4% in the normal population 3
• Untreated or poorly monitored hypertension carries the highest risk, with a 5-fold increased rupture risk compared to normotensive patients 2

Impact of Blood Pressure Control on Aneurysm Risk

While no randomized controlled trials have specifically examined whether antihypertensive treatment reduces aneurysm formation or rupture, observational evidence suggests benefit:

• Regular blood pressure monitoring in hypertensive patients significantly reduces rupture risk compared to unmonitored hypertension (OR = 2.893) 2
• Controlled hypertension has lower rupture risk than uncontrolled hypertension, though both remain elevated compared to normotensive patients 2
• Indirect evidence from a Finnish study showed antihypertensive medication use was more frequent in patients with unruptured aneurysms, while untreated hypertension was more common in those with ruptured aneurysms 1

Specific Medication Classes: RAAS Inhibitors

ACE inhibitors and ARBs show the strongest evidence for reducing aneurysm rupture risk independent of blood pressure control:

• RAAS inhibitors reduce rupture risk by approximately 50% compared to other antihypertensive medications (OR = 0.490) 4
• ACE inhibitors specifically reduce rupture risk (OR = 0.559) 4
• ARBs show even greater benefit (OR = 0.414) 4
• This protective effect persists even among patients with controlled hypertension, suggesting mechanisms beyond blood pressure reduction alone 4

The proposed mechanism involves RAAS effects on vascular wall inflammation, endothelial dysfunction, and matrix remodeling that contribute to aneurysm pathogenesis 5, 4

Clinical Recommendations

For patients with known intracranial aneurysms and hypertension:

• Treat hypertension aggressively with antihypertensive medications (Class I, Level A) 1
• Prioritize RAAS inhibitors (ACE inhibitors or ARBs) as first-line agents when treating hypertension in patients with known aneurysms 4
• Implement regular blood pressure monitoring, as irregular monitoring increases rupture risk 3-fold compared to regular monitoring 2
• Target blood pressure control, though specific thresholds for aneurysm prevention are not established 1

For primary prevention in patients without known aneurysms:

• Control hypertension to reduce overall cardiovascular risk, which may secondarily reduce aneurysm formation risk (Class I, Level B) 1
• The relationship between hypertension treatment and prevention of aneurysm formation specifically remains uncertain 1

Important Caveats

• No prospective studies demonstrate that blood pressure control prevents aneurysm development 1
• Evidence is derived from observational cohort studies and retrospective analyses, not randomized trials 1, 2, 4
• The protective effect of RAAS inhibitors requires confirmation in prospective randomized trials 4
• Patients with irregular antihypertensive medication use have significantly higher rupture risk than those with regular use 6

Additional Risk Factor Modification

Beyond blood pressure control, other modifiable factors should be addressed:

• Smoking cessation is reasonable to reduce SAH risk (Class IIa, Level B), particularly for those smoking >20 cigarettes daily 1, 6
• Excessive alcohol consumption should be avoided 1
• Adequate dietary antioxidants, B vitamins, and omega-3 fatty acids may reduce aneurysm risk 5