Cardiac amyloidosis presenting as right ventricular failure: a case report

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A 38-year-old lady was referred to cardiology for exertional dyspnoea. Medical history included granulomatosis with polyangiitis (GPA) in remission after immunosuppressive treatment, end-stage renal failure from GPA with renal transplant complicated by allograft nephropathy requiring re-initiation of haemodialysis, and hypertension. Transthoracic echocardiography showed a dilated right ventricle with impaired function, preserved left ventricular systolic function, severe tricuspid regurgitation and high echocardiographic probability of pulmonary hypertension (PH). Computed tomography pulmonary angiogram showed no pulmonary embolism. Left and right heart catheterisation demonstrated minor coronary artery disease, pre-capillary PH, no step-up to suggest shunting, and no features of chronic thromboembolic disease. Cardiac magnetic resonance was arranged to exclude arrhythmogenic right ventricular cardiomyopathy, after counselling on the risk of nephrogenic systemic fibrosis, which showed features of cardiac amyloidosis (CA). Cardiac Pyrophosphate scan returned negative for transthyretin (ATTR) CA. Serum myeloma panel demonstrated IgA/Lambda monoclonal gammopathy (anuric). Bone marrow aspiration and fat pad biopsy were unyielding. Endomyocardial biopsy showed characteristic congophilia and apple-green birefringence. Further tissue typing at Mayo Clinic demonstrated light chain (AL) lambda-type amyloid deposition. Haematology commenced her on systemic chemotherapy. Cardiac amyloidosis is a form of restrictive cardiomyopathy from deposition of insoluble amyloid. In AL-CA, circulating free light chains exert an additional cytotoxic effect. It is unusual for cardiac amyloidosis to present with isolated RV failure; thus, a high index of suspicion is required. Additionally, persistence in diagnostic evaluation with imaging and/or histology is key. With counselling, ESRF should not preclude gadolinium-based contrast imaging. Pursuance of histology is critical to initiate appropriate chemotherapy.

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