Clinical Characteristics and Prognosis of Chinese Patients with Hereditary Transthyretin Amyloid Cardiomyopathy

Background: Hereditary transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly recognized progressive cardiomyopathy with heterogenous clinical manifestations that lead to its misdiagnosis and poor prognosis. This study was performed to describe the clinical characteristics and natural history of Chinese patients to improve clinical awareness of this condition.

Methods: In this study, we retrospectively investigated 23 patients with a confirmed diagnosis of hereditary ATTR-CM in Peking Union Medical College hospital from From January 1, 2000 to December 31, 2018.

Results: In all, 16 patients (69.6%) were males, the median age at disease onset was 45 (33,55) years old. The median duration from symptom onset to diagnosis was 30 (18,46) months. Phenotypes were classified as exclusively cardiac (n = 1, 4.3%) and mixed type (n = 22, 95.6%). The common mutations were Gly47Arg (7 patients [30.4%]) and Val30Ala (3 patients [13%]). Ventricular hypertrophy was observed in 23 (100%) patients, the mean thickness of the ventricular septum was 16.1 ± 3.9 mm, the mean thickness of the left ventricular posterior wall was 15.1 ± 2.8 mm. The mean left ventricle ejection fraction (LVEF) was 57.3 ± 11.9% and only 5 patients (21.7%) had LVEF < 50%. 18 (78.3%) patients had abnormal electrocardiography and the most common feature was pseudoinfarct pattern (56.5%). Overall survival at 12, 24, 36, 48, and 60 months after diagnosis was 77.8, 55.6, 38.9, 27.8, and 11.1%, respectively. Survival was better in patients with EF ≥50% than in those with EF < 50% [log Rank (Mantel-Cox), χ2 = 4.03, P = 0.045].

Conclusions: The clinical characteristics of ATTR are heterogeneous: men are more likely to be affected and onset symptoms are not obvious in the heart and mainly include peripheral neuropathy and autonomic neuropathy; however, LV hypertrophy, especially a thick ventricular septum and posterior wall with preserved LVEF, are often detected on echocardiography. Abnormal ECG manifestations are common. The prognosis is poor, and patients with EF > 50% have better survival. Clinicians should be more aware of the complex clinical profile of ATTR amyloidosis to avoid misdiagnosis in practice.