Long term survival in patients with cardiac amyloidosis. Prevalence and characterisation during follow-up.

ABSTRACT

BACKGROUND AND AIMS: Cardiac amyloidosis (CA) is usually characterised by a poor outcome in the short-term; clinical and instrumental features are heterogeneous and could characterise subgroups with different prognoses. The aim of our study was to describe a subgroup of patients with CA showing an impressive favourable long-term survival. METHODS: Out of 50 patients (males 65%, 63 ± 11 years) with an echocardiographic and bioptic diagnosis of CA observed from 1991 to 2009, we selected a subgroup of patients surviving more than 50 months from diagnosis (group 1). We described their features at enrolment and during follow-up, comparing them with patients surviving less than 12 months (group 2). RESULTS: We found seven patients (14%) belonging to group 1 and 26 (52%) to group 2. Four out of seven long term survivors suffered from AL amyloidosis, in one case the underlying aetiology was a chronic inflammatory disease, while in two cases remained unknown. At enrolment, group 1 patients showed higher systolic blood pressure with respect to group 2 (140 ± 25 vs. 112 ± 18 mmHg, respectively, p=0.011), and a less thick interventricular septum (IVS) (IVS thickness > 15 mm in 29% vs. 69% of patients, p = 0.049). No patient of group 1 presented left ventricular restrictive filling pattern (0 vs. 31% in group 1 and 2 respectively, p = 0.035), atrial fibrillation (0 vs. 35%, p = 0.024), or progression towards a more severe disease during follow-up. CONCLUSIONS: A not negligible proportion of patients with CA can have a long-term survival. They showed a less severe disease at diagnosis, with substantial stability over time. Further studies on larger populations are necessary to understand the mechanisms underlying this more favourable natural history of the disease.