RESUMO
AIMS: Cardiac amyloidosis is a diffuse disease affecting all cardiac chambers. The value of right ventricular free-wall (RVfw) strain is uncertain as an echocardiographic red flag. We hypothesized that RVfw strain is of added value for diagnostic and prognostic purposes in patients with transthyretin cardiac amyloidosis (ATTR-CA). METHOD: ATTR-CA diagnosis required positive Tc-99m pyrophosphate (PYP) scintigraphy and negative serum clonal dyscrasia. Patients with left ventricular hypertrophy (LVH) (interventricular septal thickness ≥1.2cm) by echocardiography and negative PYP scintigraphy served as controls after exclusion of AL-CA. Longitudinal strain was computed with speckle tracking echocardiography. RESULTS: We studied, 108 subjects with ATTR-CA and 106 controls with LVH, retrospectively. RVfw strain was independently associated with the diagnosis of ATTR-CA after adjusting for classical echocardiographic parameters, namely, relative apical sparing (RAS), e' and E/e'. RVfw strain ≥-16% was incremental to LV RAS in the overall group and in the subgroup without extreme wall thickness (≤1.4 cm) (Harrell's-C, net reclassification improvement (NRI) = 0.213, p<0.001and NRI 0.463, p=0.015, respectively). Major adverse cardiovascular and cerebrovascular events (MACCE: heart failure hospitalization, stroke, death) occurred in 47 ATTR-CA patients, during follow-up (median: 38, range: 6-60 months). RVfw strain ≥-16% was associated with 3-fold increased risk of MACCE in ATTR-CA patients independently of age, comorbidities, BNP and tafamidis treatment. RVfw strain was additive to LVEF for risk stratification (X2 10.2, p =0.017). CONCLUSION: RVfw strain >-16% has incremental value to LV RAS for the differential diagnosis of ATTR-CA among LVH phenotypes, and is associated with poor prognosis.
