What is the role of aspirin (acetylsalicylic acid) in managing patients with hypertension?

Role of Aspirin in Managing Hypertension

Low-dose aspirin (75-100 mg/day) should only be prescribed to hypertensive patients with high cardiovascular risk (≥20% 10-year risk or ≥5% cardiovascular death risk) and well-controlled blood pressure (<150/90 mmHg), as the benefits outweigh bleeding risks only in these specific populations. 1

Risk-Benefit Assessment for Aspirin Use

Aspirin therapy in hypertension requires careful consideration of both cardiovascular benefits and bleeding risks:

Benefits:

• Reduces major cardiovascular events by approximately 15% 1
• Reduces acute myocardial infarction by approximately 36% 1, 2
• No significant effect on stroke incidence 1, 2

Risks:

• Increases major hemorrhagic events by 65% 1, 2
• Approximately doubles the risk of major extracranial bleeding 1

Patient Selection Algorithm for Aspirin Therapy

Recommended for:

• Hypertensive patients <80 years with:
  • 10-year cardiovascular disease risk ≥20% OR
  • Cardiovascular death risk ≥5% (based on SCORE model) 1
  • Blood pressure controlled to <150/90 mmHg 1
  • Established cardiovascular disease (secondary prevention) 1

Specific high-benefit subgroups:

• Patients with elevated serum creatinine >115 μmol/l (1.3 mg/dl) 1, 3
• Patients with diabetes mellitus 4, 2
• Patients with higher baseline systolic (≥180 mmHg) or diastolic (≥107 mmHg) blood pressure 1, 3

Not recommended for:

• Patients with low cardiovascular risk where harm may outweigh benefits 1
• Patients with uncontrolled hypertension 1
• Patients with high bleeding risk without compelling cardiovascular indications 1

Dosing and Administration

• Optimal dose: 75-100 mg daily 1
• Timing: No specific recommendation for timing in hypertension management
• Duration: Long-term therapy for eligible patients 1

Important Clinical Considerations

Interaction with Antihypertensive Medications

• Low-dose aspirin does not interfere with blood pressure-lowering effects of antihypertensive medications, including ACE inhibitors 5
• No need to adjust antihypertensive medication doses when adding aspirin 5

Monitoring

• Regular reassessment of cardiovascular risk and bleeding risk 1
• Monitor for signs of gastrointestinal bleeding 1, 2
• Periodically reassess blood pressure control 1

Common Pitfalls to Avoid

1. Prescribing aspirin to all hypertensive patients regardless of risk: The benefit-risk ratio is favorable only in high-risk patients 1
2. Using aspirin for blood pressure control: Despite some claims, aspirin is not an antihypertensive medication and should not be used for blood pressure lowering 6
3. Ignoring bleeding risk factors: Age >70 years, history of GI bleeding, concurrent use of anticoagulants/NSAIDs, and uncontrolled hypertension increase bleeding risk 1, 4
4. Failure to ensure adequate blood pressure control: Uncontrolled hypertension may attenuate aspirin's cardiovascular benefits and increase bleeding risk 1

Special Populations

Diabetic Patients with Hypertension

• Aspirin therapy is recommended for diabetic hypertensive patients with established cardiovascular disease 4
• For primary prevention in diabetics, consider aspirin if 10-year CVD risk is >5-10% 4
• Particularly beneficial in diabetic patients with target organ damage 4

Elderly Patients

• Benefits may be greater due to higher baseline cardiovascular risk
• However, bleeding risk also increases with age
• Use with caution in patients >80 years 1

In conclusion, aspirin is not a treatment for hypertension itself but rather an adjunctive therapy for reducing cardiovascular events in selected high-risk hypertensive patients with well-controlled blood pressure.