title: Prognostic implication of relative regional strain ratio in cardiac amyloidosis.
abstract: Cardiac amyloidosis (CA) is a rapidly progressive disease that portends poor prognosis. Our objective was to evaluate the prognostic impact of relative regional strain ratio (RRSR, a measure of the relative apical sparing of longitudinal strain (LS)) in CA.
  
  
  
  This is a retrospective study evaluating 97 patients with CA from 2004 to 2013. Patients were included if they met criteria for CA based on endomyocardial biopsy or advanced imaging criteria coupled with either extracardiac biopsy or genetic analysis. Baseline clinical and imaging data were collected and compared between light-chain amyloidosis (AL) (n=59) and transthyretin amyloidosis (ATTR) (n=38) subtypes. RRSR was defined as the average apical LS divided by the sum of the average mid and basal LS values. A Cox proportional hazards model was used to assess the effects of clinical and echocardiographic characteristics, including RRSR, on the outcome of time to death or heart transplantation.
  
  
  
  Despite younger age, the AL subtype had a statistically significant association with the composite outcome as compared with ATTR (p=0.022). Log-transformed RRSR was independently associated with the composite outcome at 5 years (HR 2.45 (1.36 to 4.40), p=0.003). Patients with low ejection fraction and high RRSR had the worst prognosis. In multivariable analysis, RRSR remained predictive of the primary outcome (p=0.018). Addition of covariates related to systolic function (global LS and ejection fraction) to the model attenuated this effect.
  
  
  
  High RRSR is adversely prognostic in patients with cardiac amyloid. This novel tool is both diagnostic and prognostic and may have implications in management and suitability for treatment.
authors.affiliation: Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas, USA.
authors.forename: Alpana
authors.initials: A
authors.lastname: Senapati
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Brett W
authors.initials: BW
authors.lastname: Sperry
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Justin L
authors.initials: JL
authors.lastname: Grodin
authors.affiliation: Cardiovascular Medicine, Tokushima University Hospital, Tokushima, Japan.
authors.forename: Kenya
authors.initials: K
authors.lastname: Kusunose
authors.affiliation: Peter Munk Cardiac Center, Ted Rogers Program in Cardiotoxicity Prevention, Toronto General Hospital, University of Toronto, Toronto, Canada.
authors.forename: Paaladinesh
authors.initials: P
authors.lastname: Thavendiranathan
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Wael
authors.initials: W
authors.lastname: Jaber
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Collier
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Mazen
authors.initials: M
authors.lastname: Hanna
authors.forename: Zoran B
authors.initials: ZB
authors.lastname: Popovic
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Dermot
authors.initials: D
authors.lastname: Phelan
mesh_terms: D000368:Aged; D028227:Amyloid Neuropathies, Familial / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy; D001706:Biopsy; D009202:Cardiomyopathies / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy; D016009:Chi-Square Distribution; D018450:Disease Progression; D015150:Echocardiography, Doppler; D005260:Female; D016027:Heart Transplantation; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009200:Myocardial Contraction; D009206:Myocardium / Q000473:pathology; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013314:Stress, Mechanical; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left