What is the role of blood thinners, such as aspirin (acetylsalicylic acid) or heparin, in the treatment of sudden sensorineural hearing loss (SSNHL)?

Blood Thinners in Sudden Sensorineural Hearing Loss (SSNHL)

Blood thinners such as aspirin or heparin should not be routinely prescribed for the treatment of sudden sensorineural hearing loss (SSNHL). 1, 2

Evidence Against Blood Thinners in SSNHL

The American Academy of Otolaryngology-Head and Neck Surgery provides a strong recommendation against the routine use of vasoactive substances, vasodilators, and thrombolytics (including blood thinners) for SSNHL treatment. This recommendation is based on:

• Systematic reviews of randomized controlled trials showing a preponderance of harm over benefit 1
• Lack of consistent evidence supporting vascular etiology as the primary cause of most SSNHL cases 1
• Potential serious side effects including bleeding, hypotension, arrhythmias, and drug interactions 1

The Cochrane Collaborative review of vasodilators and vasoactive substances for SSNHL found only three RCTs meeting inclusion criteria, all with high risk of bias due to poor methodology and small sample sizes. The heterogeneity in methodology and outcomes assessment prevented conclusive evidence of efficacy 1.

Vascular Theory and Blood Thinners

While vascular theories of SSNHL exist, the evidence remains contradictory:

• Some studies have demonstrated hypercoagulability in blood samples of SSNHL patients 1, 3
• Reduced perilymphatic oxygen tension has been observed in SSNHL patients 1
• However, histopathological and clinical evidence against the vascular theory exists 1

Despite these theoretical mechanisms, blood thinners and other vasoactive agents that have been tried include:

• Aspirin
• Heparin
• Prostaglandin E1
• Calcium antagonists
• Pentoxifylline
• Dextran
• Defibrinogenation therapy

None have shown consistent clinical benefit in well-designed studies 1.

Limited Evidence for Blood Thinners

Some older, smaller studies have suggested potential benefits:

• A 1979 study of 23 patients treated with intravenous heparin showed recovery in 69.6% of cases, but this was similar to the spontaneous recovery rate of 66%, and complications like priapism were reported 4
• Some small studies have explored extracorporeal treatments involving heparin for fibrinogen and LDL removal, but these remain experimental 3, 5

Current Standard of Care for SSNHL

The evidence-based approach to SSNHL management includes:

1. First-line treatment: Oral corticosteroids started promptly, ideally within the first 2 weeks of symptom onset 2, 6
2. Second-line/salvage treatment: Intratympanic steroid perfusion, typically offered 2-6 weeks after symptom onset if incomplete recovery 2
3. Optional adjunctive therapy: Hyperbaric oxygen therapy may be considered within 3 months of diagnosis 2

Prognostic Factors and Monitoring

Factors affecting prognosis include:

• Patient age
• Presence of vertigo at onset
• Degree of hearing loss
• Time between onset and treatment 2, 6

Audiometric evaluation should be performed:

• At the conclusion of treatment
• Within 6 months of completing treatment 2

Conclusion

Despite some theoretical basis for vascular mechanisms in SSNHL, current clinical guidelines strongly recommend against the routine use of blood thinners like aspirin or heparin for SSNHL treatment due to lack of proven efficacy and potential for harm. Corticosteroids remain the first-line treatment with the strongest evidence base for improving outcomes in SSNHL.