The prognostic value of right ventricular deformation derived from cardiac magnetic resonance tissue tracking for all-cause mortality in light-chain amyloidosis patients

Background: Early detection of right ventricular (RV) dysfunction is vital for determining the prognosis of light-chain amyloidosis (AL) patients. While few studies focused on RV deformation due to the limitation of research methods. The aim of this study was to determine the prognostic significance of RV myocardial strain in AL patients assessed by cardiac magnetic resonance (CMR) tissue tracking.

Methods: Sixty-four AL patients (28 females and 36 males, mean age 58±12.8 years old; range 25-81 years old) were enrolled from 1 October 2014 through 31 March 2017 and compared with 20 age- and sex-matched controls. Fifty-one AL patients met the criteria for cardiac amyloidosis (CA). Deformation parameters of both RV and left ventricle (LV) were measured by the CMR tissue tracking technique including myocardial global radial peak strain (GRPS), global circumferential peak strain (GCPS), and global longitudinal peak strain (GLPS). The follow-up time was 20 months or until the occurrence of death.

Results: Thirty-two (50%) had preserved RV ejection fraction (RVEF ≥45%). AL patients had significantly lower RV-GRPS (20.3±2.12 vs. 31.31±7.61), GCPS (-2.12±0.88 vs. -13.71±2.53), and GLPS (-5.33±0.64 vs. -14.239±2.99) than controls even RVEF remain preserved (all P<0.001). Compared with controls and patients without CA, RV-GRPS (12.26±1.26 vs. 29.72±3.54, P<0.001) and RV-GLPS (-3.78±2.25 vs. -5.66±2.08, P<0.05) were significantly lower in patients with CA. Cox multivariate analyses demonstrated that RV-GRPS [hazard ratio (HR) =0.93, 95% CI: 0.88-0.98, P=0.007] and Mayo stage were (HR =3.11, 95% CI: 1.30-7.41, P=0.01) predictors of mortality in AL patients.

Conclusions: CMR tissue tracking is a feasible and highly reproducible technique for the analysis of RV deformation and could aid in the early diagnosis of RV involvement in AL patients. RV-GRPS of RV strain and Mayo stage provides prognostic information about mortality in AL patients.