Acyclovir Prophylaxis in Cardiac Transplant Recipients

Primary Recommendation

• The American College of Cardiology recommends that cardiac transplant recipients who are HSV-seropositive should receive acyclovir prophylaxis (or valacyclovir/famciclovir) starting at transplantation and continuing for at least 1 year post-transplant, with consideration for extension if ongoing immunosuppression is required 1

HSV Prophylaxis Strategy

Who Requires Prophylaxis

• HSV-seropositive cardiac transplant recipients require prophylaxis, as without it, 60-80% of seropositive immunosuppressed patients experience HSV reactivation 1
• HSV-seronegative recipients do not require acyclovir prophylaxis regardless of donor serostatus 2, 3, 4, 5, 6, 7
• Pre-transplant serologic testing for anti-HSV IgG is mandatory to guide prophylaxis decisions 2, 3, 4, 5, 7

Recommended Agents and Dosing

• First-line options for prophylaxis include acyclovir 400 mg PO twice daily, valacyclovir 500 mg PO twice daily, or famciclovir 250 mg PO twice daily 8, 1, 9
• For acyclovir-resistant HSV, foscarnet 40 mg/kg IV every 8 hours is necessary for all future prophylaxis 9

Duration of Prophylaxis

• The standard duration of prophylaxis is at least 1 year post-transplant 8, 1
• Extended prophylaxis beyond 1 year is indicated for patients requiring ongoing systemic immunosuppression, those with a history of frequent HSV reactivations pre-transplant, and those who develop HSV reactivation requiring treatment 8, 1

VZV Prophylaxis Strategy

Rationale for Extended Coverage

• The same acyclovir regimen used for HSV prophylaxis is also effective against VZV 2, 3, 4, 5, 10, 6
• VZV disease carries substantial morbidity and mortality in immunosuppressed patients 2, 3, 4, 5, 10, 6

VZV-Seronegative Patients

• VZV-seronegative patients must strictly avoid contact with anyone with active VZV infection or reactivation 2, 3, 4, 5, 10, 6
• VZV-seronegative patients should receive VZV immunoglobulin rapidly after exposure to potentially infected persons 2, 3, 4, 10, 6

Important Clinical Considerations

Consequences of HSV Reactivation Without Prophylaxis

• HSV reactivation causes significant mucosal damage, increased pain, limited ability to maintain oral hydration and nutrition, and increased risk of bacterial and fungal superinfections 1, 9, 8

Managing Acyclovir Resistance

• Suspect resistance when lesions persist despite standard acyclovir therapy 9
• Treatment approach for acyclovir-resistant HSV includes foscarnet 40 mg/kg IV every 8 hours for active infection, and topical cidofovir gel 1% once daily for 5 days for accessible mucocutaneous lesions 9

Common Pitfalls to Avoid

• Do not extend prophylaxis to day 100 only in cardiac transplant recipients—the evidence supports at least 1 year duration given ongoing immunosuppression 8
• Do not assume CMV prophylaxis covers all herpes viruses—letermovir requires separate HSV prophylaxis 8, 1, 9
• Do not use acyclovir for CMV prophylaxis—it has failed to prevent CMV disease 2, 3, 4, 5, 7
• Do not give prophylaxis to HSV-seronegative patients—it provides no benefit 2, 3, 4, 5, 6, 7