Mid-basal left ventricular longitudinal dysfunction as a prognostic marker in mutated transthyretin-related cardiac amyloidosis

Aim: Mutated transthyretin (TTRv) cardiac amyloidosis (CA) represents an uncommon form of CA. Our study aimed to assess the best echocardiographic prognostic parameter in the early stage of TTRv amyloidosis with cardiomyopathy. Methods: In total, 99 patients with TTRv in New York Heart Association class I or II and with no clinical history of previous cardiac disease were studied. Assessment with 99mTc-DPD whole-body scan showed CA in 46 patients. At the first medical contact, an echocardiographic examination was performed. In addition to conventional left ventricular (LV), echocardiographic measurements [ejection fraction (EF), dimensions and diastolic function, global longitudinal strain (GLS), longitudinal strain of the 4 apical segments, longitudinal strain of the 12 mid-basal segments (MBLS)] and their ratio [relative regional strain ratio (RRSR)] were obtained. Patient outcome was evaluated during a follow-up with an average duration of six years. Cardiac death and appropriate implantable cardiac defibrillator (ICD) shock were considered major events. Results: A higher value of LV thickness, E/E’, and RRSR and lower LV volumes, EF, GLS, MBLS were observed in patients with CA than the ones with only TTRv. During follow-up (median of 7.7 years), 25 major events (23 cardiac death and 2 appropriate ICD shocks) occurred. The logistic univariate analyses showed that LV EF, LV septal thickness, E/E’, GLS, and MBLS were all predictors of cardiovascular death. In multivariate analysis, MBLS was the only independent predictor of major events. A cut off of -14 of MBLS was selected as the best value to discriminate a worse prognosis on Kaplan-Meyer analysis. Conclusion: Longitudinal dysfunction is observed in the early stages of ATTRv amyloidosis with cardiomyopathy. Medio-basal LV longitudinal dysfunction is a strong independent echocardiographic predictor of cardiac death.