Chang Hao-Chih, Kuo Ling, Chung Fa-Po, Yu Wen-Chung
Department of Medicine, Taipei Veterans General Hospital Taoyuan Branch, 100, Sec.3, Chenggong Road, Taoyuan District, Taoyuan 330023, Taiwan.
Cardiovascular Research Center, National Yang Ming Chiao Tung University, 155, Sec. 2, Linong Street, Beitou District, Taipei 112304, Taiwan.
Eur Heart J Case Rep. 2023 Jul 13;7(7):ytad308. doi: 10.1093/ehjcr/ytad308. eCollection 2023 Jul.
Using technetium (Tc)-labelled pyrophosphate (PYP) cardiac scintigraphy, a non-invasive diagnosis of transthyretin amyloid (ATTR) cardiomyopathy can be made without histopathological confirmation. In patients suspected of ATTR cardiomyopathy, however, atypical presentations may necessitate further investigation.
A 30-year-old man with hypertension and end-stage renal disease on peritoneal dialysis presented with progressive exertional dyspnoea. Left ventricular hypertrophy (LVH) with a maximal end-diastolic wall thickness up to 16 mm was detected on echocardiography. Speckle-tracking analysis revealed a reduced longitudinal strain of left ventricle with a relative apical sparing pattern. Although the absence of monoclonal gammopathy, a grade 3 myocardial uptake in Tc-PYP cardiac scintigraphy, and negative TTR gene mutation inferred the diagnosis of wild-type ATTR, the relative youth of the patient still raised concerns regarding the diagnosis. Under clinical doubt, he underwent further testing. In non-contrast cardiac magnetic resonance (CMR) with native T1 mapping, the native T1 myocardial value was within the normal range. In endomyocardial biopsy (EMB), there was no evidence of amyloid deposition, negative Congo red staining, and no immunohistochemical evidence of transthyretin expression. These results excluded the diagnosis of ATTR cardiomyopathy and prevented subsequent unnecessary treatments.
When patients with unexplained LVH meet the non-invasive diagnostic criteria for ATTR cardiomyopathy, an EMB should be considered in selected cases. Patients presenting at an atypical age for wild-type ATTR cardiomyopathy, absence of extracardiac symptoms/signs or classic electrocardiogram features for cardiac amyloidosis should be suspected of another diagnosis and require further CMR or EMB to confirm.
使用锝（Tc）标记的焦磷酸盐（PYP）心脏闪烁扫描术，无需组织病理学确认即可对转甲状腺素蛋白淀粉样变（ATTR）心肌病进行无创诊断。然而，在疑似ATTR心肌病的患者中，非典型表现可能需要进一步检查。
一名30岁患有高血压且正在接受腹膜透析的终末期肾病男性，出现进行性劳力性呼吸困难。超声心动图检测到左心室肥厚（LVH），最大舒张末期壁厚达16 mm。斑点追踪分析显示左心室纵向应变降低，呈相对心尖保留模式。尽管没有单克隆丙种球蛋白病，Tc-PYP心脏闪烁扫描术显示心肌摄取为3级，且TTR基因突变阴性提示野生型ATTR的诊断，但患者相对年轻仍对该诊断存在疑虑。在临床怀疑的情况下，他接受了进一步检查。在采用天然T1映射的非对比心脏磁共振（CMR）检查中，天然T1心肌值在正常范围内。在心内膜心肌活检（EMB）中，没有淀粉样蛋白沉积的证据，刚果红染色阴性，也没有转甲状腺素蛋白表达的免疫组化证据。这些结果排除了ATTR心肌病的诊断，避免了后续不必要的治疗。
当不明原因LVH的患者符合ATTR心肌病的无创诊断标准时，在某些选定病例中应考虑进行EMB。对于野生型ATTR心肌病发病年龄不典型、无心脏外症状/体征或心脏淀粉样变性的经典心电图特征的患者，应怀疑有其他诊断，需要进一步进行CMR或EMB以确诊。
