Light chain and transthyretin cardiac amyloidosis: Clinical characteristics, natural history and prognostic factors

Abstract

Introduction and objectives: Light-chain amyloidosis (AL-CA) and transthyretin amyloidosis (ATTR-CA) are the most common types of cardiac amyloidosis (CA). We sought to study the clinical characteristics and prognosis of both diseases.

Methods: We conducted a single-centre, retrospective review of all patients diagnosed with CA between 1998 and 2018. Clinical characteristics, complementary tests, survival and other adverse clinical events were studied.

Results: We identified 105 patients with CA, 65 ATTR-CA and 40 AL-CA. Mean age was 74.4 years; 24.8% were women. In both groups, heart failure was the most frequent clinical presentation (55.2%). The most prevalent electrocardiographic findings were the pseudoinfarct pattern (68.5%) and a Sokolow-Lyon index < 1.5 mV (67.7%), with no differences between the two subtypes of CA. One-year, 3-year, and 5-year survival was 43.3%, 40.4% and 35.4%, respectively, in AC-AL patients, and 85.1%, 57.3% and 31.4% in AC-ATTR patients (p = 0.004). AL-CA subtype (HR 3.41; 95% CI 1.45-8.06; p = 0.005), previous admission for heart failure (HR 4.25; 95% CI 1.63-11.09; p = 0.003) and a NYHA class III-IV (HR 2.76; 95% CI; 1.09-7.03; p = 0.033) were independent predictors of mortality, while beta-blocker therapy was associated with longer survival (HR 0.23; 95% CI 0.09-0.59; p = 0.002).

Conclusions: Differences exist between the clinical presentation of AL-CA and ATTR-CA patients. Both diseases, particularly AL-CA, are associated with poor life prognosis.

Keywords: Amiloidosis cardíaca; Cadenas ligeras; Cardiac amyloidosis; Heart failure; Insuficiencia cardíaca; Light chain; Transthyretin; Transtirretina.