Is a workup warranted in patients with aspirin (acetylsalicylic acid) sensitivity who experience bleeding?

Workup for Aspirin Sensitivity with Bleeding

For patients with aspirin sensitivity who experience bleeding, a diagnostic workup is warranted to identify the underlying mechanism and guide management decisions. 1

Assessment of Aspirin Sensitivity

Initial Evaluation

• Obtain a detailed history of bleeding events, including timing, severity, and relationship to aspirin use 1
• Document the type of bleeding (gastrointestinal, intracranial, etc.) and quantify blood loss when possible 1, 2
• Assess for concomitant use of other medications that may increase bleeding risk:
  • Anticoagulants
  • P2Y12 inhibitors (clopidogrel, prasugrel, ticagrelor)
  • NSAIDs
  • Selective serotonin reuptake inhibitors 2

Laboratory Testing

• Complete blood count to assess for anemia and thrombocytopenia 3
• Coagulation studies (PT/INR, aPTT) to rule out underlying coagulation disorders 3
• Consider platelet function testing:
  • VerifyNow aspirin assay can identify aspirin sensitivity/resistance 4, 5
  • Platelet aggregation studies in response to arachidonic acid, collagen, epinephrine, and ADP 3

Risk Stratification

Bleeding Risk Factors

• Age >60 years (increased risk) 1
• History of gastrointestinal bleeding 1, 2
• Concurrent use of anticoagulants or other antiplatelet agents 1
• Renal failure or severe liver disease 1
• Low platelet count (thrombocytopenia) 1

Thrombotic Risk Assessment

• Evaluate indication for aspirin therapy:
  • Primary prevention (lower thrombotic risk) 1
  • Secondary prevention (higher thrombotic risk) 1
• Recent acute coronary syndrome or coronary stent placement (high risk) 1
• History of stroke or transient ischemic attack 1

Management Considerations

For Patients with Acute Bleeding

• Withhold aspirin in patients with serious or life-threatening bleeding 1
• Consider alternative antiplatelet therapy based on indication and bleeding risk 1, 6
• For patients with high thrombotic risk, consult cardiology about the risk/benefit of discontinuing therapy 1

For Patients with History of Bleeding on Aspirin

• Consider lower dose aspirin (75-100 mg) for maintenance therapy 1
• Add proton pump inhibitor for patients with history of GI bleeding 1
• For patients requiring dual antiplatelet therapy with history of bleeding:
  • Continue aspirin and consult cardiology about P2Y12 inhibitor management 1
  • Consider shorter duration of dual antiplatelet therapy if appropriate 1

Special Considerations

Aspirin Desensitization

• For patients with true aspirin allergy but requiring therapy for high thrombotic risk, aspirin desensitization is preferred 1
• This should be performed under medical supervision with appropriate monitoring 1

Perioperative Management

• For high-risk endoscopic procedures:
  • Low thrombotic risk: discontinue aspirin 5 days before procedure 1
  • High thrombotic risk: continue aspirin and consult cardiology 1
• For cardiac surgery patients, preoperative platelet function testing may identify those at higher risk of perioperative bleeding 4

Monitoring After Workup

• Follow-up complete blood count to monitor for ongoing or recurrent bleeding 3
• Reassess need for aspirin therapy regularly, weighing thrombotic versus bleeding risks 1
• Consider alternative antiplatelet strategies if recurrent bleeding occurs despite preventive measures 1, 6

Remember that the absolute risk of major bleeding with low-dose aspirin ranges from 0.48-3.64 cases per 1000 person-years, with a relative risk of 1.4 compared to non-use 2. This risk must be carefully balanced against the cardiovascular benefits, particularly in primary prevention settings 1.