Hypersensitivity myocarditis and outcome after heart transplantation.

Background: Hypersensitivity myocarditis (HSM) is associated with the use of multiple drugs and has been occasionally observed in patients awaiting heart transplantation (HTx). However, whether HSM at the time of HTx affects long-term prognosis, including acute cellular rejection (ACR) and antibody-mediated rejection (AMR), after HTx remains unclear.

Methods: Between 2000 and 2010, 759 consecutive patients underwent de novo HTx at Columbia University Medical Center and were retrospectively reviewed. Clinical characteristics and pathologic findings of patients with a pre-HTx HSM diagnosed by histologic evaluation of the explanted heart were analyzed. Prognosis after HTx was compared between patients with and without pre-HTx HSM.

Results: HSM was observed in 21 patients (2.7%), but in no case was HSM clinically diagnosed. Twelve patients (57%) had received dobutamine infusions. HSM patients had varying degrees of perivascular or interstitial eosinophilic infiltrates with rare necrosis in the explanted heart. The number of biopsy specimens diagnosed with ACR (International Society for Heart and Lung Transplantation Grade ≥2R) was 11 (3.9%) in HSM patients and 197 (2.2%) in patients without HSM (p = 0.06) during the first year post-HTx, and 11 (3.8%) in HSM patients and 78 (1.5%) in patients without HSM (p = 0.006) after the second year post-HTx. Post-HTx survival did not differ in patients with or without pre-HTx HSM.

Conclusions: HSM at the time of HTx is associated with an increased frequency of late ACR after HTx. Post-HTx survival is not influenced by pre-HTx HSM.