Transplanting the unexpected: a case report of a heart allograft with wild-type transthyretin cardiac amyloid.

BACKGROUND: Cardiac amyloidosis is increasingly recognized as a cause of heart failure. Here we present a case of a heart transplant patient that inadvertently received an allograft with wild-type transthyretin amyloidosis.

CASE SUMMARY: A 62-year-old man with severe ischaemic biventricular dysfunction underwent an orthotopic heart transplantation. Donor heart details were limited to a report of moderate left ventricular hypertrophy, presumably from chronic hypertension. Post-operatively, the patient did well, but post-transplant imaging was suspicious for an underlying infiltrative cardiomyopathy. Endomyocardial biopsy confirmed that he had inadvertently received an allograft with wild-type transthyretin amyloidosis. Over the subsequent 7 years, he was followed in the Heart Transplant Clinic and was asymptomatic for 5 years post-transplantation. He then gradually developed signs of volume overload with serial imaging showing increased ventricular hypertrophy indicating progression of the cardiac amyloidosis. Subsequently, his condition deteriorated with multiple heart failure hospitalizations, ultimately favouring palliation, and died 7.5 years post-transplantation. Post-mortem autopsy analysis showed extensive allograft amyloid deposition without evidence of rejection or vasculopathy.

DISCUSSION: This is the first case report of a patient that inadvertently received an allograft with cardiac amyloidosis and provides insight into the natural history of this rare clinical scenario. Based on serial imaging and post-mortem histopathologic analysis, it was clear that there was progression of the underlying cardiac amyloidosis post-transplantation. We hypothesize that this occurred through the process of amyloid seeding. This case highlights the unique clinical and histopathologic findings of cardiac amyloidosis as well as the nuances regarding donor heart selection for transplantation.