Is sildenafil (phosphodiesterase inhibitor) safe to use in patients with an ascending aortic aneurysm?

Safety of Sildenafil in Patients with Ascending Aortic Aneurysm

Sildenafil should be used with caution in patients with ascending aortic aneurysms due to its vasodilatory effects that could potentially increase wall stress on the aneurysm, though direct evidence specifically contraindicating its use is limited. 1

Mechanism of Concern

• Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor that causes vasodilation in tissues where PDE5 is expressed, including vascular smooth muscle 2
• The medication produces a mild decrease in systemic arterial pressure (approximately -8/-5.5 mmHg) in most patients 3
• Sildenafil enhances the relaxation induced by nitric oxide donors, suggesting it may potentiate vasodilatory effects on the vasculature 2
• These hemodynamic changes could theoretically increase wall stress on an already weakened aortic wall in patients with aneurysms 1

Evidence Related to Aortic Aneurysms

• There is a case report of a 28-year-old male who developed a type A aortic dissection potentially related to sildenafil use, though this patient also had a bicuspid aortic valve and ascending aortic aneurysm as underlying risk factors 1
• Current guidelines on aortic disease management do not specifically address PDE5 inhibitor use in patients with aortic aneurysms 4
• The 2024 ESC guidelines for peripheral arterial and aortic diseases recommend optimal cardiovascular risk management for patients with aortic aneurysms but do not specifically mention PDE5 inhibitors 4

Risk Assessment Considerations

• The risk of aortic dissection increases rapidly when ascending aortic diameter exceeds 55 mm 4
• Patients with ascending aortic aneurysms should be monitored regularly with imaging surveillance as recommended by guidelines 4
• The presence of risk factors such as uncontrolled hypertension, rapid aneurysm growth (≥10 mm per year or ≥5 mm per 6 months), or family history of acute aortic events should prompt more cautious management 4

Recommendations for Clinical Practice

• For patients with small to moderate ascending aortic aneurysms (<50 mm) without additional risk factors, sildenafil may be used with appropriate monitoring 4
• For patients with larger aneurysms (≥50 mm), consider alternative treatments for erectile dysfunction 4
• If sildenafil must be used in patients with aortic aneurysms:
  • Start with the lowest effective dose 3
  • Monitor blood pressure before and after administration 3
  • Educate patients about symptoms of aortic complications (sudden severe chest or back pain) that would warrant immediate medical attention 4
  • Avoid concomitant use with nitrates, which is absolutely contraindicated due to potentially severe hypotension 3

Special Considerations

• Patients with bicuspid aortic valves or connective tissue disorders (e.g., Marfan syndrome) may have inherently weaker aortic walls and could be at higher risk of complications with vasodilators 4, 1
• Patients with hypertension should have well-controlled blood pressure before considering sildenafil 4
• The decision to use sildenafil should take into account the size of the aneurysm, rate of growth, presence of symptoms, and overall cardiovascular risk profile 4

While there is limited direct evidence specifically addressing sildenafil use in patients with ascending aortic aneurysms, a cautious approach is warranted given the theoretical concerns and the case report of aortic dissection potentially associated with sildenafil use in a patient with predisposing aortic conditions 1.