How to image cardiac amyloidosis.

Abstract

A 74-year-old man presented with decreasing exercise tolerance and mild ankle edema. He was previously fit but was now breathless on climbing 2 flights of stairs. He had no history of angina, orthopnea, or paroxysmal nocturnal dyspnea. His medical history included non–insulin-dependent diabetes mellitus treated for 10 years and mild hypertension. Six years earlier he had been diagnosed with a monoclonal gammopathy of unknown significance. At that time, a bone marrow biopsy showed 30% overall cellularity with 5% to 10% plasmacytosis (normal <4%) and immunoglobulin light-chain restriction. Approximately 3 years ago, he developed deep vein thrombosis and was treated with low-molecular-weight heparin. A year later, leg swelling occurred and was attributed to venous insufficiency. The following year, he developed progressive fatigue on exertion, and an abnormal ECG (Figure 1) led to a treadmill test that was considered normal. An echocardiogram showed concentric wall thickening (Movie 1 in the Data Supplement), and the possibility of cardiac amyloidosis was raised. A fat pad biopsy was negative for amyloid deposits. The bone marrow biopsy performed in 2005 (when his monoclonal gammopathy of unknown significance was diagnosed) was restained and was negative for amyloid. At that time, serum-free λ light chains were 108.9 mg/L (normal range, 5.7–26.3) with κ light chains of 13 mg/L (normal, 3.3–19) and an abnormal ratio of 0.12 (normal, 0.26–1.65). His brain natriuretic peptide measured 275 pcg/mL. He was treated with oral diuretics, which improved leg swelling, but because of persistent symptoms, he sought medical care at our institution. On review of symptoms, he denied jaw claudication, symptoms of postural hypotension, easy bruising, or tongue swelling. He did give a history suggestive of neuropathy with a leathery feeling in his feet but no numbness in his hands. Medications included metformin 500 mg twice a day, aspirin 80 mg daily, lisinopril …