Pulmonary Wild Type TTR Amyloidosis in a Post Orthotopic Heart Transplant Patient

Abstract

Introduction In patients with systemic amyloidosis with pulmonary involvement, the most common amyloid subtype is thought to be light chain (AL) amyloidosis. However, retrospective studies have shown wild-type ATTR (wtATTR) deposits to be an incidental finding at autopsy in 14% of patients despite being rarely symptomatic. Case Report A 70-year-old male presents with progressive NYHA II symptoms and worsening bilateral lower extremity neuropathy nearly three years following orthotopic heart transplantation for wtATTR cardiac amyloidosis. As the donor was low risk, his immediate post-operative course was uncomplicated save for mild coronary allograft vasculopathy and hypertriglyceridemia. Initial workup of his dyspnea revealed normal biventricular function. Given his history of amyloidosis, repeat cardiac biopsy was performed and failed to show evidence of amyloid deposition. A PYP scan was similarly performed without suggestion of cardiac involvement. After failing to improve clinically despite two rounds of antibiotics, he underwent a chest CT demonstrating a new left lower lobe ground-glass opacification with tree-in-bud nodules and PFTs showing mild obstructive disease. Follow-up bronchoscopy with endobronchial biopsy was without evidence of infection, sirolimus-related pneumonitis, or malignancy but curiously did reveal evidence of wtATTR, confirmed by mass spectroscopy. Summary At the present time, wtATTR stabilizers such as tafamidis are not approved in the United States for pulmonary wtATTR amyloidosis nor for amyloid-related polyneuropathy. It remains unknown whether his presenting symptoms are attributable to the wtATTR amyloid infiltrate. One must wonder whether treatment of his pulmonary wtATTR using off-label tafamidis would translate into symptomatic improvement and potentially improve his quality (and perhaps even quantity) of life.