Nuclear Medicine.
Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine.
Medicine (Baltimore). 2021 Apr 30;100(17):e25582. doi: 10.1097/MD.0000000000025582.
Patients with cardiac amyloidosis light chain (AL) present with negative Tc-99m pyrophosphate (PYP) scintigraphy (absent or mild heart uptake). On the contrary, patients with cardiac amyloidosis transthyretin (ATTR) present with positive Tc-99m PYP scanning (intensive heart uptake). We present a false positive Tc-99m PYP scintigraphy (grade 2, the heart-to-contralateral ratio is 1.65) in a patient with AL.
A 42-year-old Chinese man complained of effort intolerance, chest discomfort, and short of breath progressively over 1 year. New York Heart Association Class III. Physical examination showed legs swelling. Laboratory revealed elevated brain natriuretic peptide of 23,031 ng/mL (0-88) and Troponin-T of 273.4 ng/mL (0-14).
Cardiac amyloidosis light chain. Evidences: free light chains (FLCs): decreased serum free kappa/lambda ratio of 0.043 (0.31-1.56). Immunofixation electrophoresis: a positive lambda light chain monoclonal protein. Cardiac biopsy: HE: Ambiguity Congo red strain. Myocardial immunofluorescence: positive lambda light chain. Myocardial immunohistochemistry: positive lambda light chain, negative kappa light chain, and TTR.
Furosemide 40 mg qd, torasemide 20 mg qd, spirolactone 20 mg qd, potassium chloride 10 mL per 500 mL urine, atorvastatin calcium tablet 20 mg qd, aspirin enteric-coated tablets 100 mg qd during the 2-weeks in-hospital.
The patient died 2 months later after discharge.
False positive Tc-99m PYP scintigraphy may rarely presented in patients with cardiac amyloidosis light chain. So, the clonal plasma cell process based on the FLCs and immunofixation is a base to rule out AL cardiac amyloidosis when we interpret a positive Tc-99m PYP scintigraphy.
患有心脏轻链淀粉样变（AL）的患者 Tc-99m 焦磷酸盐（PYP）闪烁扫描呈阴性（心脏摄取缺失或轻微）。相反，患有心脏转甲状腺素淀粉样变（ATTR）的患者 Tc-99m PYP 扫描呈阳性（心脏摄取强烈）。我们报告了一例 AL 患者出现假阳性 Tc-99m PYP 闪烁扫描（2 级，心脏与对侧的比值为 1.65）。
一名 42 岁的中国男性，在 1 年内逐渐出现劳累不耐受、胸痛和呼吸困难。纽约心脏协会（NYHA）心功能分级为 III 级。体格检查发现下肢肿胀。实验室检查示脑利钠肽升高至 23031ng/ml（0-88），肌钙蛋白-T 升高至 273.4ng/ml（0-14）。
心脏轻链淀粉样变。依据：游离轻链（FLC）：血清游离κ/λ比值降低至 0.043（0.31-1.56）。免疫固定电泳：λ 轻链单克隆蛋白阳性。心脏活检：HE：刚果红染色阳性。心肌免疫荧光：λ 轻链阳性。心肌免疫组化：λ 轻链阳性，κ 轻链阴性，转甲状腺素（TTR）阴性。
呋塞米 40mg，qd；托拉塞米 20mg，qd；螺内酯 20mg，qd；氯化钾 10ml/500ml 尿量；阿托伐他汀钙片 20mg，qd；阿司匹林肠溶片 100mg，qd。住院期间共 2 周。
出院后 2 个月，患者死亡。
心脏轻链淀粉样变患者的 Tc-99m PYP 闪烁扫描可能很少出现假阳性。因此，当我们解释 Tc-99m PYP 闪烁扫描阳性时，基于 FLC 和免疫固定的克隆性浆细胞过程是排除 AL 心脏淀粉样变的基础。
