Evaluation of myocardial strain assessed by CMR tissue-tracking to predict adverse cardiovascular events in patients with cardiac amyloidosis
Authors: Fernandez Galera R , Dentamaro I , Belahnech Y , Cia X , Gutierrez L , Gonzalez-Alujas M T , Galian L , Teixido G , Casas G , Servato L , Gonzalez M T , Cuellar H , Burcet G , Guala A , Rodriguez-Palomares J F 
Published: October 2021

Abstract

Background
Cardiac affectation in amyloidosis is presented among 50% patients what implies worse prognostic. Early diagnosis and prognostic stratification is mandatory after the appearance of new therapies that could modify the course of the disease.

Purpose
The aim of our study was to assess the prognostic value of cardiac magnetic resonance parameters, including Tissue deformation, in cardiac amyloidosis patients.

Methods
We recruited patients (p) prospectively followed in our cardiomyopathy unit, for a mean period of 10 years (from 2010 to 2020) who were diagnosed with CA. Baseline clinical, laboratory and echocardiographic data were obtained. Contrast-enhanced CMR was performed on a 1.5 T clinical scanner. Routine analysis was performed with a semi-automatic software for volumetric analysis. When late gadolinium enhancement was present, percentage of area of enhancement (LGE) was calculated.All strain parameters were measured off-line using dedicated software. Left ventricular circumferential strain (CS) measurements were obtained using mid-ventricular level short-axis cine views. Longitudinal strain (LS) derived from cine SSFP of 2-, 3-, and 4-chamber long axis views.Finally we evaluated the CMR parameters related with the combined event of mortality and heart failure in the follow-up.

Results
A total of 98 p were included, with a mean age of 67.5±16.9 years old. Mean follow-up was 42,2±32 months. 22 p (24,4%) had light-chain amyloidosis (AL), 34 p (37,8%) wild type transthyretin amyloidosis (ATTRwt) and 34 p (37,8%) familiar transthyretin amyloidosis (ATTRm). 59p (60,8%) died or present heart failure during the follow-up. Patients who died or present heart failure in the follow-uo had lower left ventricular ejection fraction (48,25±12,2% vs 56,13±11,03%, p=0,003), higher myocardial mass (156,05±54,8g vs 120,84±56,1g, p=0,007), higher LGE (8,6±6,8% vs 4,4±2%), worst GLS (−14,76±6,1% vs −18,67±6,2%) and worst GCS (−23,3±9,7% vs −30,04±9,1%). Both, GLS and GCS were independently associated with the combined event of dead or heart failure when evaluated within a multivariate analysis in a Cox regression model, but GCS was the stronger predictor of events in the follow-up over other CMR parameters like LGE an myocardial mass (p&lt;0,001). Tertile distribution for GCS identified subgroups with different adverse events, particularly for the lowest-risk tertile: GCS &lt;−34%, who had a combinated event in 13,6% of cases, significantly lower than patients in the mid-risk tertile (41,5%) and highest-risk tertile (53,8%) (Log-rank p=0,02)

Conclusion
Mortality and appearance of heart failure in cardiac amyloid patients is high. The assessment of myocardial strain parameters by CMR tissue-tracking in this population is useful to predict adverse outcomes in the follow-up. Particularly, GCS, stratify patients in subgroups with different risk of events, with added value to classical CMR parameters.

Funding Acknowledgement
Type of funding sources: None. Death & Heart Failure by GCS